US20040214368A1 - Microlens array with improved fill factor - Google Patents

Microlens array with improved fill factor Download PDF

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US20040214368A1
US20040214368A1 US10/851,090 US85109004A US2004214368A1 US 20040214368 A1 US20040214368 A1 US 20040214368A1 US 85109004 A US85109004 A US 85109004A US 2004214368 A1 US2004214368 A1 US 2004214368A1
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layer
forming
microlens array
microlens
array
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Howard Rhodes
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144Devices controlled by radiation
    • H01L27/146Imager structures
    • H01L27/14601Structural or functional details thereof
    • H01L27/14609Pixel-elements with integrated switching, control, storage or amplification elements
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144Devices controlled by radiation
    • H01L27/146Imager structures
    • H01L27/14601Structural or functional details thereof
    • H01L27/14625Optical elements or arrangements associated with the device
    • H01L27/14627Microlenses
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144Devices controlled by radiation
    • H01L27/146Imager structures
    • H01L27/14683Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H01L27/14685Process for coatings or optical elements

Definitions

  • the present invention relates generally to a microlens array for use in a solid-state image sensor and in particular to a microlens array having an improved fill factor, and a method for producing the same.
  • Solid-state image sensors also known as imagers, were developed in the late 1960s and early 1970s primarily for television image acquisition, transmission, and display.
  • An imager absorbs incident radiation of a particular wavelength (such as optical photons, x-rays, or the like) and generates an electrical signal corresponding to the absorbed radiation.
  • semiconductor-based imagers including charge coupled devices (CCDs), photodiode arrays, charge injection devices (CIDs), hybrid focal plan arrays, and CMOS imagers.
  • Current applications of solid-state imagers include cameras, scanners, machine vision systems, vehicle navigation systems, video telephones, computer input devices, surveillance systems, auto focus systems, star trackers, motion detector systems, image stabilization systems and data compression systems for high-definition television.
  • These imagers typically consist of an array of pixel cells containing photosensors, where each pixel produces a signal corresponding to the intensity of light impinging on that element when an image is focused on the array. These signals may then be used, for example, to display a corresponding image on a monitor or otherwise used to provide information about the optical image.
  • the photosensors are typically phototransistors, photoconductors or photodiodes, where the conductivity of the photosensor or the charge stored in a diffusion corresponds to the intensity of light impinging on the photosensor. The magnitude of the signal produced by each pixel, therefore, is proportional to the amount of light impinging on the photosensor.
  • microlens array with an imager array, wherein the microlens array comprises a convex microlens for each pixel.
  • the microlenses refract incident radiation from the circuitry region of the pixel to the photosensor region, thereby increasing the amount of light reaching the photosensor and thereby increasing the fill factor of the pixels.
  • Other uses of microlens arrays include intensifying illuminating light on the pixels of a nonluminescent display device such as a liquid crystal display device to increase the brightness of the display, forming an image to be printed in a liquid crystal or light emitting diode printer, and as focusing means for coupling a luminescent device or a receptive device to an optical fiber.
  • microlens arrays Despite the use of microlens arrays, a large amount of light incident on an imager is not directed onto the photosensor due to the geometry of the microlens array. In particular, light incident on the space between individual lenses (the lens-lens space), and on the edges of the pixel beyond the edges of an individual lens remains uncaptured by the microlens, and never impacts the photosensor. Additionally, the typical practice of forming the microlens array on a separate substrate from the pixel array leads to problems of lens-pixel alignment that results in additional lost light.
  • microlens array having an improved fill factor formed on the same substrate as a pixel array.
  • a simple method of fabricating a microlens array having an improved fill factor is also needed.
  • the present invention provides a microlens array for use in a solid-state imager having a pixel array, wherein each microlens of the microlens array may correspond to a pixel cell of the imager pixel array.
  • Each microlens consists of two layers: a lower refractive layer, and an upper insulation layer.
  • the refractive layer is formed of transparent material with a suitable refractive index, which may be an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene, a polyimide, a thermoset resin such as an epoxy resin, a photosensitive gelatin, or a radiation curable resin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate.
  • the insulation layer is radiation-transparent and assists in capturing light at the edges of the pixel, thereby improving the fill factor of the microlens array.
  • Suitable materials for the insulation layer include silicon insulators such as silicon oxide, silicon nitride, or silicon oxynitride that have been formed by a low temperature process. Also provided are methods for forming the microlens array of the present invention.
  • FIG. 1 is a side cross-sectional view showing the principal elements of a solid-state imager having a microlens array according to one embodiment of the present invention.
  • FIG. 2 is a top view of the microlens array of FIG. 1.
  • FIG. 3 is a cross-sectional view of a CMOS imager pixel cell having a microlens constructed in accordance with an embodiment of the present invention.
  • FIG. 4 is a representative diagram of the CMOS imager pixel cell of FIG. 3.
  • FIG. 5 is a cross-sectional view of a semiconductor wafer undergoing the process of a preferred embodiment of the invention.
  • FIG. 6 shows the wafer of FIG. 5 at a processing step subsequent to that shown in FIG. 5.
  • FIG. 7 shows the wafer of FIG. 5 at a processing step subsequent to that shown in FIG. 6.
  • FIG. 8 shows the wafer of FIG. 5 at a processing step subsequent to that shown in FIG. 7.
  • FIG. 9 is an illustration of a computer system having an imager with a microlens array according to the present invention.
  • wafer and substrate are to be understood as including silicon-on-insulator (SOI) or silicon-on-sapphire (SOS) technology, doped and undoped semiconductors, epitaxial layers of silicon supported by a base semiconductor foundation, and other semiconductor structures. Furthermore, when reference is made to a “wafer” or “substrate” in the following description, previous process steps may have been utilized to form regions or junctions in the base semiconductor structure or foundation. In addition, the semiconductor need not be silicon-based, but could be based on silicon-germanium, germanium, or gallium arsenide.
  • pixel refers to a picture element unit cell containing a photosensor and transistors for converting electromagnetic radiation to an electrical signal.
  • CMOS imager pixel For purposes of illustration, a representative CMOS imager pixel is illustrated in the figures and description herein. However, this is just one example of the type of imagers and pixel cells thereof with which the invention may be used. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
  • FIGS. 1 and 2 a solid-state imager 20 containing an embodiment of the microlens array 22 of the present invention is shown in FIGS. 1 and 2.
  • the imager 20 comprises a microlens array or light condensing layer 22 formed over a pixel array 26 as part of the same substrate 30 , which may be any of the types of substrate described above.
  • the pixel array 26 is comprised of a plurality of pixel sensor cells 28 formed in the substrate, and is covered by a protective layer 24 that acts as a passivation and planarization layer for the imager 20 .
  • Protective layer 24 may be a layer of BPSG, PSG, BSG, silicon dioxide, silicon nitride, polyimide, or other well-known light transmissive insulator.
  • the microlens array or light condensing layer 22 is formed on the protective layer 24 , and is comprised of a plurality of microlenses 32 .
  • the microlens array 22 is formed so that a microlens 32 is formed above each pixel cell 28 .
  • the microlens array 22 is formed such that the focal point of the array is centered over the photosensitive elements in each pixel cell 28 .
  • the device also includes a spacer layer 25 under the mircolens array 22 .
  • spacer layer 25 is adjusted such that the photosensitive element is at a focal point for the light traveling through microlens array 22 .
  • the spacer layer 25 may have a thickness of from about 1 ⁇ m to about 20 ⁇ m.
  • a color filter, fluorescent material film, or other device for converting the wavelength of incident light may be used with the pixel array 26 by placing the device on top of the protective layer 24 and beneath the microlens array 22 .
  • each pixel sensor cell 28 contains a photosensor 34 , which may be a photodiode, photogate, or the like.
  • a photogate photosensor 34 is depicted in FIGS. 3 through 4.
  • An applied control signal PG is applied to the photogate 34 so that when incident radiation 100 in the form of photons strikes the photosensor 34 the photo-generated electrons accumulate in the doped region 36 under the photosensor 34 .
  • a transfer transistor 38 is located next to the photosensor 34 , and has source and drain regions 36 , 40 and a gate stack 42 controlled by a transfer signal TX.
  • the drain region 40 is also called a floating diffusion region or a floating diffusion node, and it passes charge received from the photosensor 34 to output transistors 44 , 46 and then to readout circuitry 48 .
  • a reset transistor 50 comprised of doped regions 40 , 52 and gate stack 54 is controlled by a reset signal RST which operates to reset the floating diffusion region 40 to a predetermined initial voltage just prior to signal readout.
  • the gate stacks 42 , 54 of the pixel cell 28 include a silicon dioxide or silicon nitride insulator 56 on the substrate 30 , which in this example is a p-type substrate, a conductive layer 58 of doped polysilicon, tungsten, or other suitable material over the insulating layer 56 , and an insulating cap layer 60 of, for example, silicon dioxide, silicon nitride, or ONO (oxide-nitride-oxide).
  • a silicide layer 59 may be used between the polysilicon layer 58 and the cap 60 , if desired.
  • Insulating sidewalls 62 are also formed on the sides of the gate stacks 42 , 54 .
  • a field oxide layer 64 around the pixel cell 28 serves to isolate it from other pixel cells in the array.
  • a second gate oxide layer 57 may be grown on the silicon substrate and the photogate semi-transparent conductor 66 is patterned. In the case that the photosensor is a photodiode, no second gate oxide layer 57 and no photogate semi-transparent conductor 66 is required. Furthermore, for the case of a photodiode, a transfer gate is optional.
  • the microlens array 22 of a preferred embodiment is formed so that a microlens 32 is formed above each pixel cell 28 , as can be seen in FIGS. 3 through 5.
  • the microlens 32 has three transparent layers, a refractive layer 70 and an insulation layer 72 and spacer layer 25 .
  • the refractive layer 70 is fashioned from transparent material with a suitable refractive index which may be an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene, a polyimide, a thermoset resin such as an epoxy resin, a photosensitive gelatin, or a radiation curable resin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate.
  • a suitable refractive index which may be an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene, a polyimide, a thermoset resin such as an epoxy resin, a photosensitive gelatin, or a radiation curable resin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate.
  • an optical thermoplastic such as polymethylmethacrylate, polycarbon
  • the insulation layer 72 is also transparent, and is made from a silicon insulator such as silicon oxide, silicon nitride, or silicon oxynitride that has been formed by a low temperature process, such as a plasma enhanced chemical vapor deposition process conducted at a temperature within the range of approximately 200 to 400 degrees Celsius.
  • a silicon insulator such as silicon oxide, silicon nitride, or silicon oxynitride that has been formed by a low temperature process, such as a plasma enhanced chemical vapor deposition process conducted at a temperature within the range of approximately 200 to 400 degrees Celsius.
  • the shape of the microlens 32 as seen from above may be circular, lenticular, ovoid, rectangular, hexagonal or any other suitable shape.
  • the microlens 32 operates to refract incident radiation 100 from the circuitry region of the pixel cell 28 to the photosensor region.
  • the microlens 32 is a plano-convex lens having a generally semi-circular cross-section.
  • Light radiation 100 is typically perpendicularly incident to the pixel cell 28 , and if no microlens were used, light radiation not directed at the photosensor 34 would not ever strike it, i.e., light radiation directed at the reset gate 54 , for example, would strike the reset gate 54 and not the photosensor 34 .
  • microlens which because of its convex shape acts to condense or focus incident radiation 100 into a smaller area than that of the microlens 32 , enables light radiation not originally directed at the photosensor 34 to be redirected towards the photosensor 34 .
  • light radiation 100 incident on an outer edge of the microlens 32 is refracted as it passes through the microlens towards the optical axis of the microlens 32 , which is positioned over the photosensor 34 , and therefore strikes the photosensor 34 , whereas an unrefracted beam would not strike the photosensor 34 .
  • the present invention provides an insulation layer 72 covering the refractive layer 70 , thereby effectively expanding the area of the pixel cell 28 that is covered by a refractive surface, so that a greater proportion of radiation incident on the pixel cell 28 is directed to the photosensor 34 , thereby improving the fill factor of the pixel sensor cell 28 .
  • the microlens array 22 can be used in a CMOS imager 20 , as is shown in FIGS. 1, 3 and 4 , or may be used in a CCD imager.
  • the microlens array 22 is manufactured through a process described as follows, and illustrated by FIGS. 6 through 9.
  • a substrate 30 which may be any of the types of substrates described above, having a pixel array 26 , peripheral circuits, contacts and wiring formed thereon by well-known methods, is provided.
  • a protective layer 24 of BPSG, BSG, PSG, silicon dioxide, silicon nitride or the like is formed over the pixel array 26 to passivate it and to provide a planarized surface.
  • a spacing layer 25 is formed over the protective layer 24 .
  • a lens forming layer 80 is formed on the spacer layer 25 by spin-coating or other suitable means.
  • the lens forming layer 80 may be an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene, a polyimide, a thermoset resin such as an epoxy resin, a photosensitive gelatin, or a radiation curable resin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate.
  • an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene
  • a polyimide such as an epoxy resin
  • a photosensitive gelatin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate.
  • the lens forming layer 80 is patterned by conventional photolithography, or other suitable means, to form a plurality of lens forming regions 82 .
  • each lens forming region 82 overlies a pixel cell 28 , although alternative constructions in which a lens forming region 82 overlies multiple pixel cells 28 are foreseen.
  • the shape of the lens forming regions 82 as seen from above may be circular, lenticular, ovoid, rectangular, hexagonal or any other suitable shape.
  • the substrate 30 is then treated, by heat treatment or other suitable treatment, to form refractive lenses 70 from the lens forming regions 82 .
  • the treatment used to form the refractive lenses 70 depends on the material used to form the lens forming layer 80 . If the material of the lens forming layer 80 may be heat treated, then heat treatment processes such as baking may be used. If the material is extremely photosensitive, then special light exposure techniques may be used, as further described below.
  • Heat treatment relies on the use of flowable materials such as optical thermoplastics, polyimides, and thermoset resins, which may be melted at relatively low temperatures to produce a smooth-surfaced lens.
  • a typical baking process involves heating the substrate 30 at a temperature of approximately 100 to 350 degrees Celsius for a suitable length of time, such as 30 minutes.
  • the lens forming regions 82 melt and surface tension in the resultant liquid results in the formation of a smooth convex lens 70 with a semi-circular cross-section.
  • Certain photosensitive materials such as gelatin and radiation curable resins exhibit a phenomenon in which, when selectively exposed to light, unreacted compounds move from the unexposed regions to the exposed regions, resulting in a swelling of the exposed regions. This phenomenon may be used to form refractive lenses 70 from the lens forming regions 82 .
  • the lens forming regions 82 are selectively illuminated with light from a mercury lamp or the like through the top or bottom of the substrate, which has been masked with a photomask or other suitable device for creating a lens pattern.
  • the illumination time depends on the thickness of the lens forming regions 82 , the degree of parallelism of the light beams, and the intensity of the light used, but should be sufficient to cause the lens forming regions 82 to swell into smooth convex lenses 70 having a generally semi-circular cross-section.
  • FIG. 9 shows the next step of the process, in which a transparent insulation layer 72 is formed on the lenses 70 via a low temperature deposition process such as plasma enhanced chemical vapor deposition (CVD).
  • the low temperatures are within the range of approximately 200 to 400 degrees Celsius.
  • the transparent insulation layer 72 may be formed of a silicon insulator such as silicon oxide, silicon nitride, or silicon oxynitride that is transparent to radiation.
  • a CVD process is especially preferred if the transparent insulation layer 72 is formed from silicon oxide, because the CVD process permits the use of tetraethylorthosilicate (TEOS) as the silicon source, as opposed to silane, and therefore results in improved conformal deposition.
  • TEOS tetraethylorthosilicate
  • the microlens array 22 is essentially complete at this stage, and conventional processing methods may now be performed to package the imager 20 .
  • Pixel arrays having the microlens arrays of the present invention, and described with reference to FIGS. 1-9, may be further processed as known in the art to arrive at CMOS, CCD, or other imagers.
  • the imager 20 may be combined with a processor, such as a CPU, digital signal processor or microprocessor, in a single integrated circuit, and may be used in a processor system such as the typical processor-based system illustrated generally at 400 in FIG. 10.
  • a processor based system is exemplary of a system having digital circuits which could include CMOS or other imager devices.
  • such a system could include a computer system, camera system, scanner, machine vision system, vehicle navigation system, video telephone, surveillance system, auto focus system, star tracker system, motion detection system, image stabilization system and data compression system for high-definition television, all of which can utilize the present invention.
  • a processor system such as a computer system, for example, generally comprises a central processing unit (CPU) 444 , e.g., a microprocessor, that communicates with an input/output (I/O) device 446 over a bus 452 .
  • the imager 20 also communicates with the system over bus 452 .
  • the computer system 400 also includes random access memory (RAM) 448 , and, in the case of a computer system may include peripheral devices such as a floppy disk drive 454 and a compact disk (CD) ROM drive 456 which also communicate with CPU 444 over the bus 452 .
  • the imager 20 is preferably constructed as an integrated circuit, with or without memory storage, which includes a microlens array 22 having an improved fill factor, as previously described with respect to FIGS. 1 through 9.
  • the present invention encompasses a microlens array for use in a solid-state imager such as a CMOS imager or CCD imager.
  • the microlens array has an improved fill factor due to the presence of multi-layer lenses having an insulation layer over a refractive layer.

Abstract

A microlens array for use in a solid-state imager having an improved fill factor. The microlens array includes a plurality of microlenses, each consisting of two layers: a lower refractive layer, and an upper insulation layer. The refractive layer is formed of transparent material with a suitable refractive index which may be optical thermoplastic, polyimide, thermoset resin, photosensitive gelatin, or radiation curable resin. The insulation layer is formed of transparent insulating material such as silicon oxide, silicon nitride, or silicon oxynitride. Due to the refraction of light through the insulation layer, more light at the pixel edges is captured by each microlens, thereby improving the fill factor of the microlens array. Also disclosed are methods for forming the microlens array.

Description

    FIELD OF THE INVENTION
  • The present invention relates generally to a microlens array for use in a solid-state image sensor and in particular to a microlens array having an improved fill factor, and a method for producing the same. [0001]
  • BACKGROUND OF THE INVENTION
  • Solid-state image sensors, also known as imagers, were developed in the late 1960s and early 1970s primarily for television image acquisition, transmission, and display. An imager absorbs incident radiation of a particular wavelength (such as optical photons, x-rays, or the like) and generates an electrical signal corresponding to the absorbed radiation. There are a number of different types of semiconductor-based imagers, including charge coupled devices (CCDs), photodiode arrays, charge injection devices (CIDs), hybrid focal plan arrays, and CMOS imagers. Current applications of solid-state imagers include cameras, scanners, machine vision systems, vehicle navigation systems, video telephones, computer input devices, surveillance systems, auto focus systems, star trackers, motion detector systems, image stabilization systems and data compression systems for high-definition television. [0002]
  • These imagers typically consist of an array of pixel cells containing photosensors, where each pixel produces a signal corresponding to the intensity of light impinging on that element when an image is focused on the array. These signals may then be used, for example, to display a corresponding image on a monitor or otherwise used to provide information about the optical image. The photosensors are typically phototransistors, photoconductors or photodiodes, where the conductivity of the photosensor or the charge stored in a diffusion corresponds to the intensity of light impinging on the photosensor. The magnitude of the signal produced by each pixel, therefore, is proportional to the amount of light impinging on the photosensor. [0003]
  • It is known in the art to use a microlens array with an imager array, wherein the microlens array comprises a convex microlens for each pixel. The microlenses refract incident radiation from the circuitry region of the pixel to the photosensor region, thereby increasing the amount of light reaching the photosensor and thereby increasing the fill factor of the pixels. Other uses of microlens arrays include intensifying illuminating light on the pixels of a nonluminescent display device such as a liquid crystal display device to increase the brightness of the display, forming an image to be printed in a liquid crystal or light emitting diode printer, and as focusing means for coupling a luminescent device or a receptive device to an optical fiber. [0004]
  • Despite the use of microlens arrays, a large amount of light incident on an imager is not directed onto the photosensor due to the geometry of the microlens array. In particular, light incident on the space between individual lenses (the lens-lens space), and on the edges of the pixel beyond the edges of an individual lens remains uncaptured by the microlens, and never impacts the photosensor. Additionally, the typical practice of forming the microlens array on a separate substrate from the pixel array leads to problems of lens-pixel alignment that results in additional lost light. [0005]
  • There is needed, therefore, a microlens array having an improved fill factor formed on the same substrate as a pixel array. A simple method of fabricating a microlens array having an improved fill factor is also needed. [0006]
  • SUMMARY OF THE INVENTION
  • The present invention provides a microlens array for use in a solid-state imager having a pixel array, wherein each microlens of the microlens array may correspond to a pixel cell of the imager pixel array. Each microlens consists of two layers: a lower refractive layer, and an upper insulation layer. The refractive layer is formed of transparent material with a suitable refractive index, which may be an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene, a polyimide, a thermoset resin such as an epoxy resin, a photosensitive gelatin, or a radiation curable resin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate. The insulation layer is radiation-transparent and assists in capturing light at the edges of the pixel, thereby improving the fill factor of the microlens array. Suitable materials for the insulation layer include silicon insulators such as silicon oxide, silicon nitride, or silicon oxynitride that have been formed by a low temperature process. Also provided are methods for forming the microlens array of the present invention. [0007]
  • Additional advantages and features of the present invention will be apparent from the following detailed description and drawings which illustrate preferred embodiments of the invention.[0008]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a side cross-sectional view showing the principal elements of a solid-state imager having a microlens array according to one embodiment of the present invention. [0009]
  • FIG. 2 is a top view of the microlens array of FIG. 1. [0010]
  • FIG. 3 is a cross-sectional view of a CMOS imager pixel cell having a microlens constructed in accordance with an embodiment of the present invention. [0011]
  • FIG. 4 is a representative diagram of the CMOS imager pixel cell of FIG. 3. [0012]
  • FIG. 5 is a cross-sectional view of a semiconductor wafer undergoing the process of a preferred embodiment of the invention. [0013]
  • FIG. 6 shows the wafer of FIG. 5 at a processing step subsequent to that shown in FIG. 5. [0014]
  • FIG. 7 shows the wafer of FIG. 5 at a processing step subsequent to that shown in FIG. 6. [0015]
  • FIG. 8 shows the wafer of FIG. 5 at a processing step subsequent to that shown in FIG. 7. [0016]
  • FIG. 9 is an illustration of a computer system having an imager with a microlens array according to the present invention.[0017]
  • DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
  • In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized, and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present invention. [0018]
  • The terms “wafer” and “substrate” are to be understood as including silicon-on-insulator (SOI) or silicon-on-sapphire (SOS) technology, doped and undoped semiconductors, epitaxial layers of silicon supported by a base semiconductor foundation, and other semiconductor structures. Furthermore, when reference is made to a “wafer” or “substrate” in the following description, previous process steps may have been utilized to form regions or junctions in the base semiconductor structure or foundation. In addition, the semiconductor need not be silicon-based, but could be based on silicon-germanium, germanium, or gallium arsenide. The term “pixel” refers to a picture element unit cell containing a photosensor and transistors for converting electromagnetic radiation to an electrical signal. For purposes of illustration, a representative CMOS imager pixel is illustrated in the figures and description herein. However, this is just one example of the type of imagers and pixel cells thereof with which the invention may be used. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. [0019]
  • Referring now to the drawings, where like elements are designated by like reference numerals, a solid-[0020] state imager 20 containing an embodiment of the microlens array 22 of the present invention is shown in FIGS. 1 and 2. The imager 20 comprises a microlens array or light condensing layer 22 formed over a pixel array 26 as part of the same substrate 30, which may be any of the types of substrate described above. The pixel array 26 is comprised of a plurality of pixel sensor cells 28 formed in the substrate, and is covered by a protective layer 24 that acts as a passivation and planarization layer for the imager 20. Protective layer 24 may be a layer of BPSG, PSG, BSG, silicon dioxide, silicon nitride, polyimide, or other well-known light transmissive insulator. The microlens array or light condensing layer 22 is formed on the protective layer 24, and is comprised of a plurality of microlenses 32. In a preferred embodiment, depicted in FIGS. 1 and 2, the microlens array 22 is formed so that a microlens 32 is formed above each pixel cell 28. The microlens array 22 is formed such that the focal point of the array is centered over the photosensitive elements in each pixel cell 28. The device also includes a spacer layer 25 under the mircolens array 22. The thickness of spacer layer 25 is adjusted such that the photosensitive element is at a focal point for the light traveling through microlens array 22. The spacer layer 25 may have a thickness of from about 1 μm to about 20 μm. If desired, a color filter, fluorescent material film, or other device for converting the wavelength of incident light may be used with the pixel array 26 by placing the device on top of the protective layer 24 and beneath the microlens array 22.
  • As can be seen in FIGS. 3 through 4, each [0021] pixel sensor cell 28 contains a photosensor 34, which may be a photodiode, photogate, or the like. A photogate photosensor 34 is depicted in FIGS. 3 through 4. An applied control signal PG is applied to the photogate 34 so that when incident radiation 100 in the form of photons strikes the photosensor 34 the photo-generated electrons accumulate in the doped region 36 under the photosensor 34. A transfer transistor 38 is located next to the photosensor 34, and has source and drain regions 36, 40 and a gate stack 42 controlled by a transfer signal TX. The drain region 40 is also called a floating diffusion region or a floating diffusion node, and it passes charge received from the photosensor 34 to output transistors 44, 46 and then to readout circuitry 48. A reset transistor 50 comprised of doped regions 40, 52 and gate stack 54 is controlled by a reset signal RST which operates to reset the floating diffusion region 40 to a predetermined initial voltage just prior to signal readout.
  • As can best be seen in FIG. 3, the [0022] gate stacks 42, 54 of the pixel cell 28 include a silicon dioxide or silicon nitride insulator 56 on the substrate 30, which in this example is a p-type substrate, a conductive layer 58 of doped polysilicon, tungsten, or other suitable material over the insulating layer 56, and an insulating cap layer 60 of, for example, silicon dioxide, silicon nitride, or ONO (oxide-nitride-oxide). A silicide layer 59 may be used between the polysilicon layer 58 and the cap 60, if desired. Insulating sidewalls 62 are also formed on the sides of the gate stacks 42, 54. These sidewalls may be formed of, for example, silicon dioxide, silicon nitride, or ONO. A field oxide layer 64 around the pixel cell 28 serves to isolate it from other pixel cells in the array. A second gate oxide layer 57 may be grown on the silicon substrate and the photogate semi-transparent conductor 66 is patterned. In the case that the photosensor is a photodiode, no second gate oxide layer 57 and no photogate semi-transparent conductor 66 is required. Furthermore, for the case of a photodiode, a transfer gate is optional.
  • The [0023] microlens array 22 of a preferred embodiment is formed so that a microlens 32 is formed above each pixel cell 28, as can be seen in FIGS. 3 through 5. The microlens 32 has three transparent layers, a refractive layer 70 and an insulation layer 72 and spacer layer 25. The refractive layer 70 is fashioned from transparent material with a suitable refractive index which may be an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene, a polyimide, a thermoset resin such as an epoxy resin, a photosensitive gelatin, or a radiation curable resin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate. The insulation layer 72 is also transparent, and is made from a silicon insulator such as silicon oxide, silicon nitride, or silicon oxynitride that has been formed by a low temperature process, such as a plasma enhanced chemical vapor deposition process conducted at a temperature within the range of approximately 200 to 400 degrees Celsius. The shape of the microlens 32 as seen from above may be circular, lenticular, ovoid, rectangular, hexagonal or any other suitable shape.
  • The [0024] microlens 32 operates to refract incident radiation 100 from the circuitry region of the pixel cell 28 to the photosensor region. As can be seen in FIG. 3, the microlens 32 is a plano-convex lens having a generally semi-circular cross-section. Light radiation 100 is typically perpendicularly incident to the pixel cell 28, and if no microlens were used, light radiation not directed at the photosensor 34 would not ever strike it, i.e., light radiation directed at the reset gate 54, for example, would strike the reset gate 54 and not the photosensor 34. Use of a microlens, which because of its convex shape acts to condense or focus incident radiation 100 into a smaller area than that of the microlens 32, enables light radiation not originally directed at the photosensor 34 to be redirected towards the photosensor 34. For example, light radiation 100 incident on an outer edge of the microlens 32 is refracted as it passes through the microlens towards the optical axis of the microlens 32, which is positioned over the photosensor 34, and therefore strikes the photosensor 34, whereas an unrefracted beam would not strike the photosensor 34.
  • As [0025] pixel sensor cells 28 decrease in size due to the demand for increased array density, complications in conventional photolithography and other patterning processes result in the formation of conventional microlenses that do not completely cover the pixel sensor cell 28. This can be seen mostly clearly in FIG. 3, wherein the refractive layer 70 extends across a large portion of the pixel cell 28, but due to the limitations of the patterning process does not cover the entire pixel cell 28. The present invention provides an insulation layer 72 covering the refractive layer 70, thereby effectively expanding the area of the pixel cell 28 that is covered by a refractive surface, so that a greater proportion of radiation incident on the pixel cell 28 is directed to the photosensor 34, thereby improving the fill factor of the pixel sensor cell 28. The microlens array 22 can be used in a CMOS imager 20, as is shown in FIGS. 1, 3 and 4, or may be used in a CCD imager.
  • The [0026] microlens array 22 is manufactured through a process described as follows, and illustrated by FIGS. 6 through 9. Referring now to FIG. 6, a substrate 30, which may be any of the types of substrates described above, having a pixel array 26, peripheral circuits, contacts and wiring formed thereon by well-known methods, is provided. A protective layer 24 of BPSG, BSG, PSG, silicon dioxide, silicon nitride or the like is formed over the pixel array 26 to passivate it and to provide a planarized surface. A spacing layer 25 is formed over the protective layer 24. A lens forming layer 80 is formed on the spacer layer 25 by spin-coating or other suitable means. The lens forming layer 80 may be an optical thermoplastic such as polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, or polystyrene, a polyimide, a thermoset resin such as an epoxy resin, a photosensitive gelatin, or a radiation curable resin such as acrylate, methacrylate, urethane acrylate, epoxy acrylate, or polyester acrylate.
  • Next, as shown in FIG. 7, the [0027] lens forming layer 80 is patterned by conventional photolithography, or other suitable means, to form a plurality of lens forming regions 82. In the exemplary embodiment illustrated, each lens forming region 82 overlies a pixel cell 28, although alternative constructions in which a lens forming region 82 overlies multiple pixel cells 28 are foreseen. The shape of the lens forming regions 82 as seen from above may be circular, lenticular, ovoid, rectangular, hexagonal or any other suitable shape.
  • Referring now to FIG. 8, the [0028] substrate 30 is then treated, by heat treatment or other suitable treatment, to form refractive lenses 70 from the lens forming regions 82. The treatment used to form the refractive lenses 70 depends on the material used to form the lens forming layer 80. If the material of the lens forming layer 80 may be heat treated, then heat treatment processes such as baking may be used. If the material is extremely photosensitive, then special light exposure techniques may be used, as further described below.
  • Heat treatment relies on the use of flowable materials such as optical thermoplastics, polyimides, and thermoset resins, which may be melted at relatively low temperatures to produce a smooth-surfaced lens. A typical baking process involves heating the [0029] substrate 30 at a temperature of approximately 100 to 350 degrees Celsius for a suitable length of time, such as 30 minutes. As a result of the heat applied, the lens forming regions 82 melt and surface tension in the resultant liquid results in the formation of a smooth convex lens 70 with a semi-circular cross-section.
  • Certain photosensitive materials such as gelatin and radiation curable resins exhibit a phenomenon in which, when selectively exposed to light, unreacted compounds move from the unexposed regions to the exposed regions, resulting in a swelling of the exposed regions. This phenomenon may be used to form [0030] refractive lenses 70 from the lens forming regions 82. The lens forming regions 82 are selectively illuminated with light from a mercury lamp or the like through the top or bottom of the substrate, which has been masked with a photomask or other suitable device for creating a lens pattern. The illumination time depends on the thickness of the lens forming regions 82, the degree of parallelism of the light beams, and the intensity of the light used, but should be sufficient to cause the lens forming regions 82 to swell into smooth convex lenses 70 having a generally semi-circular cross-section.
  • FIG. 9 shows the next step of the process, in which a [0031] transparent insulation layer 72 is formed on the lenses 70 via a low temperature deposition process such as plasma enhanced chemical vapor deposition (CVD). The low temperatures are within the range of approximately 200 to 400 degrees Celsius. The transparent insulation layer 72 may be formed of a silicon insulator such as silicon oxide, silicon nitride, or silicon oxynitride that is transparent to radiation. A CVD process is especially preferred if the transparent insulation layer 72 is formed from silicon oxide, because the CVD process permits the use of tetraethylorthosilicate (TEOS) as the silicon source, as opposed to silane, and therefore results in improved conformal deposition.
  • The [0032] microlens array 22 is essentially complete at this stage, and conventional processing methods may now be performed to package the imager 20. Pixel arrays having the microlens arrays of the present invention, and described with reference to FIGS. 1-9, may be further processed as known in the art to arrive at CMOS, CCD, or other imagers. If desired, the imager 20 may be combined with a processor, such as a CPU, digital signal processor or microprocessor, in a single integrated circuit, and may be used in a processor system such as the typical processor-based system illustrated generally at 400 in FIG. 10. A processor based system is exemplary of a system having digital circuits which could include CMOS or other imager devices. Without being limiting, such a system could include a computer system, camera system, scanner, machine vision system, vehicle navigation system, video telephone, surveillance system, auto focus system, star tracker system, motion detection system, image stabilization system and data compression system for high-definition television, all of which can utilize the present invention.
  • As shown in FIG. 10, a processor system such as a computer system, for example, generally comprises a central processing unit (CPU) [0033] 444, e.g., a microprocessor, that communicates with an input/output (I/O) device 446 over a bus 452. The imager 20 also communicates with the system over bus 452. The computer system 400 also includes random access memory (RAM) 448, and, in the case of a computer system may include peripheral devices such as a floppy disk drive 454 and a compact disk (CD) ROM drive 456 which also communicate with CPU 444 over the bus 452. The imager 20 is preferably constructed as an integrated circuit, with or without memory storage, which includes a microlens array 22 having an improved fill factor, as previously described with respect to FIGS. 1 through 9.
  • As can be seen by the embodiments described herein, the present invention encompasses a microlens array for use in a solid-state imager such as a CMOS imager or CCD imager. The microlens array has an improved fill factor due to the presence of multi-layer lenses having an insulation layer over a refractive layer. [0034]
  • It should again be noted that although the invention has been described with specific reference to imaging circuits having a pixel array, the invention has broader applicability and may be used in any imaging apparatus. Similarly, the process described above is but one method of many that could be used. The above description and drawings illustrate preferred embodiments which achieve the objects, features and advantages of the present invention. It is not intended that the present invention be limited to the illustrated embodiments. Any modification of the present invention which comes within the spirit and scope of the following claims should be considered part of the present invention.[0035]

Claims (15)

What is claimed as new and desired to be protected by Letters Patent of the United States is:
1-59. (Cancelled).
60. A method of forming a microlens array for use in an imaging device, said method comprising the steps of:
providing a substrate having an array of pixel sensor cells formed thereon and a protective layer over the cells;
forming a spacer layer in contact with the protective layer;
forming a lens forming layer over and in contact with the spacer layer;
forming microlens array from said lens forming layer; and
forming a radiation transparent insulation layer on said microlens array for increasing the proportion of radiation incident on said pixel sensor cells, by extending the light-capturing capabilities beyond a periphery area surrounding each individual microlens of sand microlens array, wherein said insulation layer includes silicon insulator material.
61. The method of claim 60, wherein the substrate further comprises a CMOS pixel array formed thereon.
62. The method of claim 60, wherein the substrate further comprises a CCD pixel array formed thereon.
63. The method of claim 60, wherein said step of forming the lens forming layer comprises a spin-coating process.
64. The method of claim 60, wherein the lens forming layer is a layer of material selected from the group consisting of optical thermoplastic, polyimide, thermoset resin, photosensitive gelatin, and radiation curable resin.
65. The method of claim 64, wherein the optical thermoplastic is selected from the group consisting of polymethylmethacrylate, polycarbonate, polyolefin, cellulose acetate butyrate, and polystyrene.
66. The method of claim 64, wherein the radiation curable resin is selected from the group consisting of acrylate, methacrylate, urethane acrylate, epoxy acrylate, and polyester acrylate.
67. The method of claim 60, wherein the insulation layer is a layer of material selected from the group consisting of silicon oxide, silicon nitride, and silicon oxynitride.
68. The method of claim 60, wherein said insulation layer forming step comprises a chemical vapor deposition step.
69. The method of claim 60, wherein said insulation layer forming step comprises a low temperature plasma deposition step.
70. The method of claim 69, wherein said silicon insulator material is formed by a low temperature process operation within the range of approximately 200 to 400 degrees Celsius.
71. The method according to claim 60, further comprising forming a spacer layer under said microlens array.
72. The method according to claim 71, wherein said spacer layer has a thickness of from about 1 μm to about 20 μm.
73-99. (Cancelled).
US10/851,090 1999-07-19 2004-05-24 Microlens array with improved fill factor Abandoned US20040214368A1 (en)

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060067607A1 (en) * 2004-09-30 2006-03-30 Stmicroelectronics, Inc. Method and system for vertical optical coupling on semiconductor substrate
US20060071149A1 (en) * 2004-09-30 2006-04-06 Stmicroelectronics, Inc. Microlens structure for opto-electric semiconductor device, and method of manufacture
US20060097244A1 (en) * 2004-11-09 2006-05-11 Chintamani Palsule Optical enhancement of integrated circuit photodetectors
WO2006111486A1 (en) * 2005-04-19 2006-10-26 Dkfz Deutsches Krebsforschungszentrum Optical imaging detector
US20070018213A1 (en) * 2004-06-22 2007-01-25 Dongbuanam Semiconductor Inc. CMOS image sensor and method of fabricating the same
US20080019168A1 (en) * 2006-07-24 2008-01-24 Cha-Hsin Lin Memory structure and data writing method thereof
US20080274580A1 (en) * 2007-05-03 2008-11-06 Chung-Kyung Jung Method for manufacturing image sensor
US20110068351A1 (en) * 2004-04-01 2011-03-24 Matthew Donofrio Method of Forming Three Dimensional Features on Light Emitting Diodes for Improved Light Extraction
US20110284875A1 (en) * 2004-09-22 2011-11-24 Cree, Inc. High efficiency group iii nitride led with lenticular surface
US20120050599A1 (en) * 2010-08-25 2012-03-01 Pixart Imaging Inc. Image sensing device
CN102931201A (en) * 2011-08-11 2013-02-13 中国科学院微电子研究所 Infrared focal plane array (IRFPA)-based energy-gathering micro lens array and manufacturing method thereof
US11760046B2 (en) 2019-12-31 2023-09-19 Semiconductor Components Industries, Llc Multi-layered microlens systems and related methods

Families Citing this family (56)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6376868B1 (en) * 1999-06-15 2002-04-23 Micron Technology, Inc. Multi-layered gate for a CMOS imager
JP2001195901A (en) * 2000-01-14 2001-07-19 Nippon Sheet Glass Co Ltd Illumination apparatus
JP4123667B2 (en) * 2000-01-26 2008-07-23 凸版印刷株式会社 Manufacturing method of solid-state imaging device
KR20030042305A (en) * 2001-11-22 2003-05-28 주식회사 하이닉스반도체 The method of fabrication for CMOS image sensor
JP3675402B2 (en) * 2001-12-27 2005-07-27 セイコーエプソン株式会社 OPTICAL DEVICE AND ITS MANUFACTURING METHOD, OPTICAL MODULE, CIRCUIT BOARD AND ELECTRONIC DEVICE
JP4095300B2 (en) * 2001-12-27 2008-06-04 セイコーエプソン株式会社 OPTICAL DEVICE AND ITS MANUFACTURING METHOD, OPTICAL MODULE, CIRCUIT BOARD AND ELECTRONIC DEVICE
US6638786B2 (en) * 2002-10-25 2003-10-28 Hua Wei Semiconductor (Shanghai ) Co., Ltd. Image sensor having large micro-lenses at the peripheral regions
CN100350270C (en) * 2003-01-28 2007-11-21 皇家飞利浦电子股份有限公司 X-ray detector
US6953925B2 (en) * 2003-04-28 2005-10-11 Stmicroelectronics, Inc. Microlens integration
US20040223071A1 (en) * 2003-05-08 2004-11-11 David Wells Multiple microlens system for image sensors or display units
US20050045927A1 (en) * 2003-09-03 2005-03-03 Jin Li Microlenses for imaging devices
US7420233B2 (en) * 2003-10-22 2008-09-02 Micron Technology, Inc. Photodiode for improved transfer gate leakage
US7572385B2 (en) * 2003-11-17 2009-08-11 Micron Technology, Inc. Method of forming micro-lenses
US7333267B2 (en) * 2003-11-26 2008-02-19 Micron Technology, Inc. Micro-lenses for CMOS imagers
KR100593162B1 (en) * 2004-03-22 2006-06-26 매그나칩 반도체 유한회사 Image sensor and method for fabricating the same
US20050211665A1 (en) * 2004-03-26 2005-09-29 Sharp Laboratories Of America, Inc. Methods of forming a microlens array
US7158181B2 (en) * 2004-05-04 2007-01-02 Andrew G. Cartlidge System and methods for increasing fill-factor on pixelated sensor arrays
US7738026B2 (en) * 2005-05-02 2010-06-15 Andrew G. Cartlidge Increasing fill-factor on pixelated sensors
JP4838501B2 (en) * 2004-06-15 2011-12-14 富士通セミコンダクター株式会社 Imaging apparatus and manufacturing method thereof
US7508431B2 (en) * 2004-06-17 2009-03-24 Hoya Corporation Solid state imaging device
FR2872590B1 (en) * 2004-07-02 2006-10-27 Essilor Int METHOD FOR PRODUCING AN OPHTHALMIC GLASS AND OPTICAL COMPONENT SUITABLE FOR CARRYING OUT SAID METHOD
PT1763699E (en) * 2004-07-02 2011-11-24 Essilor Int Method for producing a transparent optical element, an optical component involved into said method and the thus obtained optical element
US7235431B2 (en) * 2004-09-02 2007-06-26 Micron Technology, Inc. Methods for packaging a plurality of semiconductor dice using a flowable dielectric material
FR2879757B1 (en) * 2004-12-17 2007-07-13 Essilor Int METHOD FOR PRODUCING A TRANSPARENT OPTICAL ELEMENT, OPTICAL COMPONENT INVOLVED IN THIS METHOD AND OPTICAL ELEMENT THUS OBTAINED
TWI251931B (en) * 2004-12-29 2006-03-21 Advanced Chip Eng Tech Inc Imagine sensor with a protection layer
KR100649006B1 (en) * 2004-12-30 2006-11-27 동부일렉트로닉스 주식회사 method for manufacturing of CMOS image sensor
KR100672706B1 (en) * 2004-12-30 2007-01-22 동부일렉트로닉스 주식회사 Image sensor comprising a protected inner lens
US20060238545A1 (en) * 2005-02-17 2006-10-26 Bakin Dmitry V High-resolution autostereoscopic display and method for displaying three-dimensional images
KR100782463B1 (en) * 2005-04-13 2007-12-05 (주)실리콘화일 Separation type unit pixel of image sensor having 3 dimension structure and manufacture method thereof
US20080296644A1 (en) * 2005-05-02 2008-12-04 Samsung Electronics Co., Ltd. Cmos image sensors and methods of fabricating same
KR100672812B1 (en) * 2005-05-02 2007-01-22 삼성전자주식회사 Image sensor and method of manufacturing the same
US20060261385A1 (en) * 2005-05-23 2006-11-23 Micron Technology, Inc. Phase shift transparent structures for imaging devices
US7522341B2 (en) * 2005-07-12 2009-04-21 Micron Technology, Inc. Sharing of microlenses among pixels in image sensors
FR2888951B1 (en) * 2005-07-20 2008-02-08 Essilor Int RANDOMIZED PIXELLIZED OPTICAL COMPONENT, METHOD FOR MANUFACTURING THE SAME, AND USE THEREOF IN THE MANUFACTURE OF A TRANSPARENT OPTICAL ELEMENT
FR2888947B1 (en) * 2005-07-20 2007-10-12 Essilor Int OPTICAL CELL COMPONENT
FR2888950B1 (en) * 2005-07-20 2007-10-12 Essilor Int TRANSPARENT PIXELLIZED OPTICAL COMPONENT WITH ABSORBENT WALLS ITS MANUFACTURING METHOD AND USE IN FARICATION OF A TRANSPARENT OPTICAL ELEMENT
FR2888948B1 (en) 2005-07-20 2007-10-12 Essilor Int PIXELLIZED TRANSPARENT OPTIC COMPONENT COMPRISING AN ABSORBENT COATING, METHOD FOR PRODUCING THE SAME AND USE THEREOF IN AN OPTICAL ELEMENT
US7808023B2 (en) * 2005-08-24 2010-10-05 Aptina Imaging Corporation Method and apparatus providing integrated color pixel with buried sub-wavelength gratings in solid state imagers
KR100790225B1 (en) * 2005-12-26 2008-01-02 매그나칩 반도체 유한회사 Image sensor and method for manufacturing the same
US7352511B2 (en) * 2006-04-24 2008-04-01 Micron Technology, Inc. Micro-lenses for imagers
US7393477B2 (en) * 2006-08-15 2008-07-01 United Microelectronics Corp. Method of fabricating microlens structure
FR2907559B1 (en) * 2006-10-19 2009-02-13 Essilor Int ELECRO-COMMANDABLE OPTICAL COMPONENT COMPRISING A SET OF CELLS
FR2910642B1 (en) * 2006-12-26 2009-03-06 Essilor Int TRANSPARENT OPTICAL COMPONENT WITH TWO CELL ARRAYS
JP5030215B2 (en) * 2007-01-17 2012-09-19 国立大学法人 東京大学 Microdevice and manufacturing method thereof
FR2911404B1 (en) * 2007-01-17 2009-04-10 Essilor Int TRANSPARENT OPTICAL COMPONENT WITH CELLS FILLED WITH OPTICAL MATERIAL
JP4931160B2 (en) * 2007-09-05 2012-05-16 国立大学法人東北大学 Solid-state image sensor
US7923298B2 (en) 2007-09-07 2011-04-12 Micron Technology, Inc. Imager die package and methods of packaging an imager die on a temporary carrier
US7531373B2 (en) * 2007-09-19 2009-05-12 Micron Technology, Inc. Methods of forming a conductive interconnect in a pixel of an imager and in other integrated circuitry
US7968923B2 (en) * 2008-03-12 2011-06-28 Omnivision Technologies, Inc. Image sensor array with conformal color filters
US7894143B2 (en) * 2008-11-12 2011-02-22 Visera Technologies Company Limited Image capture lens
KR20120029727A (en) * 2010-09-17 2012-03-27 엘지이노텍 주식회사 Light emitting device package
US8602308B2 (en) * 2011-12-22 2013-12-10 Symbol Technologies, Inc. Imaging device having light field sensor
US9128218B2 (en) * 2011-12-29 2015-09-08 Visera Technologies Company Limited Microlens structure and fabrication method thereof
TWI500926B (en) * 2012-11-23 2015-09-21 Innocom Tech Shenzhen Co Ltd Flat panel x-ray detector
US10249661B2 (en) * 2014-08-22 2019-04-02 Visera Technologies Company Limited Imaging devices with dummy patterns
TWI664722B (en) * 2016-12-20 2019-07-01 精材科技股份有限公司 Semiconductor structure and method for manufacturing semiconductor structure

Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5118924A (en) * 1990-10-01 1992-06-02 Eastman Kodak Company Static control overlayers on opto-electronic devices
US5298366A (en) * 1990-10-09 1994-03-29 Brother Kogyo Kabushiki Kaisha Method for producing a microlens array
US5300263A (en) * 1992-10-28 1994-04-05 Minnesota Mining And Manufacturing Company Method of making a microlens array and mold
US5384231A (en) * 1993-08-24 1995-01-24 Eastman Kodak Company Fabricating lens array structures for imaging devices
US5420634A (en) * 1991-04-01 1995-05-30 Olympus Optical Co., Ltd. Solid state imaging device
US5453876A (en) * 1988-08-30 1995-09-26 Sharp Kabushiki Kaisha Microlens array
US5479049A (en) * 1993-02-01 1995-12-26 Sharp Kabushiki Kaisha Solid state image sensor provided with a transparent resin layer having water repellency and oil repellency and flattening a surface thereof
US5559336A (en) * 1994-07-05 1996-09-24 Santa Barbara Research Center Integrated LPE-grown structure for simultaneous detection of infrared radiation in two bands
US5610390A (en) * 1994-10-03 1997-03-11 Fuji Photo Optical Co., Ltd. Solid-state image pickup device having microlenses each with displaced optical axis
US5666175A (en) * 1990-12-31 1997-09-09 Kopin Corporation Optical systems for displays
US5691548A (en) * 1993-09-28 1997-11-25 Sharp Kabushiki Kaisha Solid state imaging device having high sensitivity and exhibiting high degree of light utilization and method of manufacturing the same
US5693967A (en) * 1995-08-10 1997-12-02 Lg Semicon Co., Ltd. Charge coupled device with microlens
US5701008A (en) * 1996-11-29 1997-12-23 He Holdings, Inc. Integrated infrared microlens and gas molecule getter grating in a vacuum package
US5796154A (en) * 1995-05-22 1998-08-18 Matsushita Electronics Corporation Solid-state imaging device with dual lens structure
US5844289A (en) * 1996-05-21 1998-12-01 Nec Corporation Solid-state image sensor with microlens and optical fiber bundle
US5887049A (en) * 1996-11-12 1999-03-23 California Institute Of Technology Self-triggered X-ray sensor
US5997621A (en) * 1992-10-06 1999-12-07 Minnesota Mining And Manufacturing Co. Coating composition having anti-reflective and anti-fogging properties
US6040591A (en) * 1997-03-25 2000-03-21 Sony Corporation Solid state imaging device having refractive index adjusting layer and method for making same
US6071443A (en) * 1996-11-27 2000-06-06 Dai Nippon Printing Co., Ltd. Method of producing lens sheet and projection screen
US6104021A (en) * 1997-04-09 2000-08-15 Nec Corporation Solid state image sensing element improved in sensitivity and production cost, process of fabrication thereof and solid state image sensing device using the same
US6171883B1 (en) * 1999-02-18 2001-01-09 Taiwan Semiconductor Manufacturing Company Image array optoelectronic microelectronic fabrication with enhanced optical stability and method for fabrication thereof
US6274917B1 (en) * 1999-10-12 2001-08-14 Taiwan Semiconductor Manufacturing Company High efficiency color filter process for semiconductor array imaging devices
US6583438B1 (en) * 1999-04-12 2003-06-24 Matsushita Electric Industrial Co., Ltd. Solid-state imaging device
US6617189B1 (en) * 2002-02-07 2003-09-09 United Microelectronics Corp. Method of fabricating an image sensor

Patent Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5453876A (en) * 1988-08-30 1995-09-26 Sharp Kabushiki Kaisha Microlens array
US5118924A (en) * 1990-10-01 1992-06-02 Eastman Kodak Company Static control overlayers on opto-electronic devices
US5298366A (en) * 1990-10-09 1994-03-29 Brother Kogyo Kabushiki Kaisha Method for producing a microlens array
US5666175A (en) * 1990-12-31 1997-09-09 Kopin Corporation Optical systems for displays
US5420634A (en) * 1991-04-01 1995-05-30 Olympus Optical Co., Ltd. Solid state imaging device
US5997621A (en) * 1992-10-06 1999-12-07 Minnesota Mining And Manufacturing Co. Coating composition having anti-reflective and anti-fogging properties
US5300263A (en) * 1992-10-28 1994-04-05 Minnesota Mining And Manufacturing Company Method of making a microlens array and mold
US5479049A (en) * 1993-02-01 1995-12-26 Sharp Kabushiki Kaisha Solid state image sensor provided with a transparent resin layer having water repellency and oil repellency and flattening a surface thereof
US5384231A (en) * 1993-08-24 1995-01-24 Eastman Kodak Company Fabricating lens array structures for imaging devices
US5691548A (en) * 1993-09-28 1997-11-25 Sharp Kabushiki Kaisha Solid state imaging device having high sensitivity and exhibiting high degree of light utilization and method of manufacturing the same
US5559336A (en) * 1994-07-05 1996-09-24 Santa Barbara Research Center Integrated LPE-grown structure for simultaneous detection of infrared radiation in two bands
US5610390A (en) * 1994-10-03 1997-03-11 Fuji Photo Optical Co., Ltd. Solid-state image pickup device having microlenses each with displaced optical axis
US5796154A (en) * 1995-05-22 1998-08-18 Matsushita Electronics Corporation Solid-state imaging device with dual lens structure
US5693967A (en) * 1995-08-10 1997-12-02 Lg Semicon Co., Ltd. Charge coupled device with microlens
US5844289A (en) * 1996-05-21 1998-12-01 Nec Corporation Solid-state image sensor with microlens and optical fiber bundle
US5887049A (en) * 1996-11-12 1999-03-23 California Institute Of Technology Self-triggered X-ray sensor
US6071443A (en) * 1996-11-27 2000-06-06 Dai Nippon Printing Co., Ltd. Method of producing lens sheet and projection screen
US5701008A (en) * 1996-11-29 1997-12-23 He Holdings, Inc. Integrated infrared microlens and gas molecule getter grating in a vacuum package
US6040591A (en) * 1997-03-25 2000-03-21 Sony Corporation Solid state imaging device having refractive index adjusting layer and method for making same
US6104021A (en) * 1997-04-09 2000-08-15 Nec Corporation Solid state image sensing element improved in sensitivity and production cost, process of fabrication thereof and solid state image sensing device using the same
US6171883B1 (en) * 1999-02-18 2001-01-09 Taiwan Semiconductor Manufacturing Company Image array optoelectronic microelectronic fabrication with enhanced optical stability and method for fabrication thereof
US6583438B1 (en) * 1999-04-12 2003-06-24 Matsushita Electric Industrial Co., Ltd. Solid-state imaging device
US6274917B1 (en) * 1999-10-12 2001-08-14 Taiwan Semiconductor Manufacturing Company High efficiency color filter process for semiconductor array imaging devices
US6617189B1 (en) * 2002-02-07 2003-09-09 United Microelectronics Corp. Method of fabricating an image sensor

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8263995B2 (en) * 2004-04-01 2012-09-11 Cree, Inc. Three dimensional features on light emitting diodes for improved light extraction
US20110068351A1 (en) * 2004-04-01 2011-03-24 Matthew Donofrio Method of Forming Three Dimensional Features on Light Emitting Diodes for Improved Light Extraction
US7554143B2 (en) * 2004-06-22 2009-06-30 Dongbu Electronics Co., Ltd. CMOS image sensor and method of fabricating the same
US20070018213A1 (en) * 2004-06-22 2007-01-25 Dongbuanam Semiconductor Inc. CMOS image sensor and method of fabricating the same
US8692267B2 (en) * 2004-09-22 2014-04-08 Cree, Inc. High efficiency Group III nitride LED with lenticular surface
US20110284875A1 (en) * 2004-09-22 2011-11-24 Cree, Inc. High efficiency group iii nitride led with lenticular surface
US8878209B2 (en) 2004-09-22 2014-11-04 Cree, Inc. High efficiency group III nitride LED with lenticular surface
US20060071149A1 (en) * 2004-09-30 2006-04-06 Stmicroelectronics, Inc. Microlens structure for opto-electric semiconductor device, and method of manufacture
US20060067607A1 (en) * 2004-09-30 2006-03-30 Stmicroelectronics, Inc. Method and system for vertical optical coupling on semiconductor substrate
US7389013B2 (en) 2004-09-30 2008-06-17 Stmicroelectronics, Inc. Method and system for vertical optical coupling on semiconductor substrate
US20080206919A1 (en) * 2004-09-30 2008-08-28 Stmicroelectronics, Inc. Method of manufacture of a microlens structure for opto-electric semiconductor device
US7704780B2 (en) 2004-11-09 2010-04-27 Aptina Imaging Corporation Optical enhancement of integrated circuit photodetectors
US20090081822A1 (en) * 2004-11-09 2009-03-26 Aptina Imaging Corporation Optical enhancement of integrated circuit photodetectors
GB2455224A (en) * 2004-11-09 2009-06-03 Micron Technology Inc Integrated circuit photodetector with an embedded microlens
US7459733B2 (en) 2004-11-09 2008-12-02 Aptina Imaging Corporation Optical enhancement of integrated circuit photodetectors
GB2420224B (en) * 2004-11-09 2009-09-09 Agilent Technologies Inc Integrated circuit photodetectors
GB2455224B (en) * 2004-11-09 2009-11-18 Micron Technology Inc Integrated circuit photodetetectors
US20070158696A1 (en) * 2004-11-09 2007-07-12 Chintamani Palsule Optical enhancement of integrated circuit photodetectors
US7208783B2 (en) 2004-11-09 2007-04-24 Micron Technology, Inc. Optical enhancement of integrated circuit photodetectors
US20060097244A1 (en) * 2004-11-09 2006-05-11 Chintamani Palsule Optical enhancement of integrated circuit photodetectors
US20090032714A1 (en) * 2005-04-19 2009-02-05 Deutsches Krebsforschungszentrum Stiftung des öffentlichen Rechts Optical imaging detector
JP2012237759A (en) * 2005-04-19 2012-12-06 Deutsches Krebsforschungszentrum Stiftung Des Offentlichen Rechts Optical imaging detector
WO2006111486A1 (en) * 2005-04-19 2006-10-26 Dkfz Deutsches Krebsforschungszentrum Optical imaging detector
US8227754B2 (en) 2005-04-19 2012-07-24 Deutsches Krebforschungszentrum Stiftung Des Oeffentlichen Rechts Optical imaging detector
US20080019168A1 (en) * 2006-07-24 2008-01-24 Cha-Hsin Lin Memory structure and data writing method thereof
US20080274580A1 (en) * 2007-05-03 2008-11-06 Chung-Kyung Jung Method for manufacturing image sensor
US20120050599A1 (en) * 2010-08-25 2012-03-01 Pixart Imaging Inc. Image sensing device
CN102931201A (en) * 2011-08-11 2013-02-13 中国科学院微电子研究所 Infrared focal plane array (IRFPA)-based energy-gathering micro lens array and manufacturing method thereof
US11760046B2 (en) 2019-12-31 2023-09-19 Semiconductor Components Industries, Llc Multi-layered microlens systems and related methods

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