CN101590995B

CN101590995B - Same plane sensor

Info

Publication number: CN101590995B
Application number: CN200810108149A
Authority: CN
Inventors: 王传蔚; 李昇达
Original assignee: Pixart Imaging Inc
Current assignee: Pixart Imaging Inc
Priority date: 2008-05-27
Filing date: 2008-05-27
Publication date: 2012-09-05
Anticipated expiration: 2028-05-27
Also published as: CN101590995A

Abstract

The invention relates to a same plane sensor comprising a fixed structure and a movable structure, wherein the fixed structure comprises a fixed arm and a fixed end which are connected with each other, the fixed arm is provided with a supporting end and a suspended end, the supporting end is connected with the fixed end, and the suspended end is suspended; and the movable structure at least comprises a body and an extending arm which are connected with each other, and also comprises an extending body which is connected to the body through extending arm; wherein the supporting end of the fixed arm is closer to the body comparing with the suspended end.

Description

Same plane sensor

Technical field

The present invention relates to a kind of same plane sensor and preparation method, the particularly a kind of same plane sensor and preparation method that can reduce residual stress to technogenic influence.

Background technology

The effect of same plane sensor is the capacitance variation that is produced because of the plan range variation between sensing two electrodes, and to produce corresponding signal, it for example can be applicable to make accelerometer (accelerometer) or gyroscope (gyro sensor) or the like.The prior art of relevant same plane sensor or its preparation method for example can be consulted United States Patent (USP) the 5th, 326, and No. 726, the 5th, 847, No. 280, the 5th, 880, No. 369, the 6th, 877, No. 374, the 6th, 892, No. 576.

Above-mentioned each prior art all has identical problem, explains as follows.See also Fig. 1; This type of microcomputer electric component includes one or more fixed structures 50 and a moving structure 60 usually; Fixed structure 50 comprises a plurality of fixed arms (fixed finger) 52; 52 of each fixed arms are as suspension, but fix by stiff end 58, are connected conducting through stiff end 58 with connecting portion 56 each other between the fixed arm 52.Stiff end 58 is fixed on the matrix (not shown) of below.60 of moving structures comprise body (proof mass) 62, adjutage (extended finger or movable finger) 64, connecting portion 66 and stiff end (anchor) 68.Except that stiff end 68 (also being fixed on the matrix of below), other part (comprising body 62, adjutage 64, connecting portion 66) of moving structure 60 suspends, when integral member is moved; The suspension part of moving structure 60 can produce with respect to fixed structure 50 and relatively move; Distance between fixed arm 52 and the adjutage 64 is changed, and when fixed arm 52 and adjutage 64 were respectively two electrodes of electric capacity, its capacitance promptly changed; Therefore; Through detecting this capacitance variation, can calculate travel direction, speed, acceleration etc., its application is decided by the purpose of design of this microcomputer electric component.

See also Fig. 2 (this is the cutaway view from the past right-hand gained of looking of X--X section of Fig. 1); Because fixed arm 52 is suspension structure with adjutage 64; In semiconductor technology, be easy to cause prying, this moment, the overlapping area of fixed arm 52 and adjutage 64 significantly reduced, and effective capacitance value is descended.Therefore, be necessary to improve, to reduce the degree of influence of technology to the structure of this type of microcomputer electric component.

Summary of the invention

First purpose of the present invention is to overcome the deficiency and the defective of prior art, proposes a kind of same plane sensor that can reduce residual stress to technogenic influence.

Second purpose of the present invention is, proposes a kind of preparation method of same plane sensor.

For reaching above-mentioned purpose, with regard to one of them viewpoint of the present invention, a kind of same plane sensor is provided; Comprise: a fixed structure, this fixed structure comprises fixed arm connected to one another and stiff end, this fixed arm has the support end and the end that suspends; Support end is connected with stiff end, and the end that suspends is for suspending; And a moving structure, this moving structure comprises body connected to one another and adjutage at least, this moving structure also includes extension body, be connected with body via adjutage, wherein, the support end of this fixed arm than the end that suspends more near body.

Moreover, with regard to another viewpoint of the present invention, a kind of same plane sensor is provided; Comprise: a fixed structure, this fixed structure comprises fixed arm connected to one another and stiff end, this fixed arm has the support end and the end that suspends; Support end is connected with stiff end, and the end that suspends is for suspending; And a moving structure, this moving structure comprises body, extension body and adjutage at least, body and extension body are connected to each other through adjutage.

In above-mentioned two kinds of same plane sensors, the continuous length on the arbitrary in length and breadth direction of this body should be not more than a higher limit, for example 60 μ m (micron)～100 μ m.

Moving structure in above-mentioned two kinds of same plane sensors can more include a spring, and this spring should have at least one tortuous place on its long direction.

In addition, for reaching above-mentioned purpose, with regard to another viewpoint of the present invention; A kind of preparation method of same plane sensor is provided; This same plane sensor comprises a fixed structure and a moving structure, and fixed structure comprises fixed arm connected to one another and stiff end, and moving structure comprises body connected to one another and adjutage at least; Preparation method comprises: a substrate is provided; On this substrate, deposited at least one deck contact layer and one deck metal level at least, and through this at least one deck contact layer and one deck metal level at least form the stiff end of this fixed structure, this stiff end treats that by first etching area is centered on; Deposition and definition metal level and channel layer to form the fixed arm of this fixed structure, reach the body and the adjutage of this moving structure, and the fixed arm of said fixed structure, and the body and the adjutage of moving structure treat that by second etching area is centered on; And remove this and first and second treat etching area.

In the said method, this first and second treats that etching area can once remove, or be divided into two or more multistep remove suddenly.

In the said method, this first and second treats that the step of etching area can comprise following steps this removal: deposition one deck overcoat; Deposition one deck shields firmly; Define the pattern of this hard shielding and overcoat; And etching this first and second treat etching area.In the above step, behind the pattern of this hard shielding of definition and overcoat, can deposit one deck shielding again.

Explain in detail through specific embodiment below, when the effect that is easier to understand the object of the invention, technology contents, characteristics and is reached.

Description of drawings

Fig. 1 marks an example of the same plane sensor structure of prior art;

Fig. 2 explains prior art problems;

Fig. 3 marks one embodiment of the present of invention;

Fig. 4 explains that the present invention can solve the problem of prior art;

Fig. 5 A, 5B mark two embodiment of the present invention;

Fig. 6 A, 6B, 6C mark three embodiment of the present invention;

Fig. 7 A-7H marks process implementing example of the present invention, and wherein figure 7A, 7C, 7E-7G are the profile along A--A section gained among Fig. 3; Fig. 7 B, 7D, 7H are the profile along B--B section gained among Fig. 3;

Fig. 8 A-8C, Fig. 9 A-9C mark two process implementing examples in addition of the present invention.

Symbol description among the figure

11 the 0th layers of silicon substrate

The 12a contact layer

The 12b-12f channel layer

The 13a-13f metal level

14 oxide areas (hollow area)

17 oxide areas (hollow area)

18 shieldings

The 18a overcoat

18b shields firmly

The 18c photoresistance

19 shieldings

30 fixed structures

32 fixed arms

The 32a end that suspends

The 32b support end

38 stiff ends

40 moving structures

42 bodies

43 extension bodies

44 adjutages

45 perforates

46,46 ' spring (connecting portion)

The tortuous place of 46a

48 fixed parts

50 fixed structures

52 fixed arms

56 connecting portions

58 stiff ends

60 moving structures

62 bodies

64 adjutages

66 connecting portions

68 stiff ends

100,200,300 micro electronmechanical zones

The specific embodiment

The icon of this specification all belongs to signal, and its dimension does not fully proportionally illustrate.

See also Fig. 3, in the first embodiment of the present invention, include at least one fixed structure 30 and a moving structure 40 in the micro electromechanical structure 100 of same plane sensor.Moving structure 40 comprises body 42, adjutage 44, connecting portion 46 and fixed part 48, connects each other; Wherein body 42, adjutage 44, connecting portion 46 are suspension structure, and fixed part 48 is a fixed structure, and it is anticipated promptly, and except that fixed part 48 was fixed on the matrix (not shown) of below, body connected to one another 42, adjutage 44, connecting portion 46 were for suspending.Among embodiment, connecting portion 46 is a spring, can elastic telescopic therein.Fixed structure 30 comprises a plurality of fixed arms 32, and it has the end of suspension 32a and support end 32b to 32 of each fixed arms as suspension, and support end 32b fixes through being connected with stiff end 38.Between each stiff end 38, then can be by bottom matrix or the more next mutual conducting of interconnect (the conducting relation is represented by dotted lines) on upper strata.One of characteristics of the present invention are that support end 32b suspends end 32a more near body 42, and are positioned at the same side with body 42, and the end 32a that suspends then is positioned at opposite side.Therefore as shown in Figure 4; Even because of technological problems causes prying; Because the suspension end 32a of fixed arm 32 and the outer rim of adjutage 44 are positioned at the same side; The prying problem that technology causes is close to both degree of influence, so fixed arm 32 still has sizable overlapping area with adjutage 44, does not influence the capacitance that is originally designed.

Fig. 5 A marks another embodiment of the present invention, in the present embodiment, includes at least one fixed structure 30 and a moving structure 40 in the micro electromechanical structure 200 of same plane sensor equally.The characteristics of present embodiment are that moving structure 40 has also comprised extension body 43 except comprising body 42, adjutage 44, connecting portion 46 and fixed part 48.Because the existence of extension body 43 all is connected the two ends of adjutage 44 with big quality, therefore can increase quality.In the present embodiment, the support end 32b of fixed arm 32 can be positioned at the same side (as shown in the figure) with body 42, also can be positioned at the same side (not shown) with extension body 43.Other part in the present embodiment structure is similar, not elsewhere specified with a last embodiment.

Fig. 5 B marks another embodiment again of the present invention; Omit among the figure and illustrate fixed structure 30; In the micro electromechanical structure 300 of present embodiment; Extension body 43 not only is provided, and body 42 all is divided into some individually in the vertical with extension body 43, but all bodies 42 link together all with extension body 43.The effect of vertically cutting apart is to lower body 42 and extension body 43 continuous length in the vertical, and to reduce prying, the upper limit of said continuous length for example can be 60 μ m (micron)～100 μ m.

Fig. 6 A marks an embodiment more of the present invention, the body 42 that only draws among the figure, and other part is omitted.In the present embodiment, body 42 is not a complete monoblock mass, but comprises the large opening 45 of many hollow outs.First effect of perforate is: on technology, be convenient to the material layer that etching is positioned at body 42 belows; Second effect is: make mass vertically, laterally or on both (only design in the present embodiment in vertically on), be unlikely to have long length continuously.In detail, shown in Fig. 6 A, the longitudinal length Y of body 42 is divided into several paragraphs Y1, Y2 ..., the longitudinal length of each paragraph all is limited under certain length, and its upper limit for example is 60 μ m～100 μ m.It is to reduce prying that this kind arranged the purpose of mode, because continuous length is limited under the preset length, therefore the degree of prying just can reduce on this direction.Certainly, the position of perforate is not limited to shown in Fig. 6 A, and for example Fig. 6 B is feasible too.Among Fig. 6 A, 6B two embodiment, length restriction only designs on vertically, but those skilled in the art are from can be after announcement of the present invention, is applied to voluntarily laterally or in length and breadth on both.And this kind engraved structure not only can design on body 42, also can design on extension body 43 certainly.

In above each embodiment, the structure of spring 46 is not limited to for example ask for an interview Fig. 6 C shown in Fig. 3,5A, the 5B; Contrast shows the simple spring structure shown in Fig. 3,5A, the 5B (top spring 46 only illustrates right half of) among the figure, with spring structure (the below spring 46 ' than sophisticated types; Only illustrate right half of); Spring 46 ' is set up at least one tortuous 46a of place, to increase the actual effective length of spring on the long direction of spring 46 (directions X among the figure).Can reduce the coefficient of elasticity of spring thus, increase the sensitivity of sensor.

Below will be with reference to Fig. 7 A-7H, and be the technology that example is explained same plane sensor of the present invention with Fig. 3.What need explanation is; Following technology is to be example with six layers of smithcraft; But the present invention is not limited to use six layers of smithcraft certainly, and its metal level can be any number of plies, and technology is certainly applicable to Fig. 5 A, 5B, 6A, 6B and all structures under notion of the present invention.See also Fig. 7 A, 7B, wherein Fig. 7 A is the profile along B--B section gained among Fig. 3 along A--A section, Fig. 7 B among Fig. 3.One the 0th layer crystal physa plate 11 at first is provided in the present embodiment, and this substrate 11 for example can be silicon substrate, with the CMOS process compatible.Follow on substrate 11 with (not shown) such as CMOS technology making transistor units; Make interconnect with technologies such as deposition, little shadow, etchings in regular turn again, like the contact layer 12a among Fig. 7 B, ground floor metal level 13a; Ground floor channel layer 12b; Second layer metal layer 13b, second layer channel layer 12c etc. also produce the stiff end 38 among Fig. 3 this moment simultaneously.Following square structure shown in the figure uses double layer of metal to make, and its contact layer and channel layer material for example can use tungsten, and before can first deposit spathic silicon or nitration case in deposits tungsten, and metal layer material then can be used aluminium, and dielectric material can use oxide such as silica.But certainly, it also is feasible using other conduction to make interconnect with dielectric material, and the metal level number can certainly change, and icon only is for example.In the pattern of each layer 12a-12c and 13a-13b, comprise overlapping oxide areas 14 (first treats etching area); Part outside the micro electromechanical structure zone 100 does not illustrate, in the hope of simplifying drawing.The material of oxide areas 14 for example can use silica.Unlikely other zone that undermines when asking following etching oxidation object area 14 should be enclosed in oxide areas 14 within the protective ring (not shown), and this protective ring can form when each layer 12a-12c and 13a-13b form pattern in the lump.

Next the interconnect structure of deposition several layers above substrate comprises channel layer 12d-12f and metal level 13c-13f.For the demand of electromechanical circuits function, must some zone be isolated from each other, the figure exemplified shows isolates with oxide areas 17, and this oxide areas 17 can form when forming channel layer 12d-12f and metal level 13c-13f in the lump.

Hookup 7A and 7B see also Fig. 7 C and 7D again, in a kind of therein preferable enforcement kenel; Can above substrate, deposit one deck shielding 18 and define pattern; Oxide areas 17 (second treats etching area) is come out, and this layer shielding 18 for example can be photoresistance, forms pattern with visualization way; Or also can adopt other material, for example metal level or amorphous silicon layer etc.Adopt metal level or amorphous silicon layer embodiment, hold the back explanation as shielding.

Hookup 7C then sees Fig. 7 E, under the covering of shielding 18, carries out oxide etching, removes the oxide in the zone 17.Etched mode for example can be anisotropic (anisotropic) reactive ion etch (RIE, reactive ion etch).In etching process, shielding 18 is haply near consume fully.

Note that above step, belong to option and inessential from Fig. 7 C to Fig. 7 E; That can omit and after Fig. 7 A, 7B step, directly be connected the step of Fig. 7 F.

Then see Fig. 7 F; No matter whether shield 18 consumes fully; Deposit one deck shielding 19 again, the material of this shielding for example is a photoresistance, and oxide areas 14 is carried out oxide etching; Its mode for example can be used hydrofluoric acid vapor etching (HF vapor etch) or monolith substrate immersed in the acid tank and carry out Wet-type etching with buffer oxide etch (BOE, buffered oxide etch) mode.

Shown in Fig. 7 G,

photoresistance

18,19 is removed simultaneously at last, can be obtained the microcomputer electric component desired, because the relation of profile position only can be seen moving structure 40 among the figure.Fig. 7 H shows along the being seen structure of B--B section among Fig. 3, can see the part (body 42) of fixed structure 30 (comprising fixed arm 32 and stiff end 38) and moving structure 40.

Fig. 8 A hookup 7A; Show and adopt metal level or amorphous silicon layer as the embodiment that shields; In the present embodiment; Should be on topmost metal layer 13f deposition overcoat 18a (overcoat can be the double-decker that nitration case or oxide layer add nitration case) earlier, deposit hard screen layer 18b (hard screen layer can be metal level or amorphous silicon layer) afterwards above that.In icon embodiment, hard screen layer 18b and overcoat 18a are earlier through a pattern definition, with the zone 100 of opening micro electromechanical structure.Owing to be provided with hard shielding 18b, so photoresistance 18c must not need, and visual technology is required and whether decision deposits photoresistance 18c again, and icon is an example with deposition photoresistance 18c, in other words need twice define pattern in this practice.Plant the practice but the present invention is not limited thereto, also can directly once define its pattern, shown in Fig. 9 A.

Then see Fig. 8 B and 9B, carry out the etching of once oxidation thing earlier, to remove the oxide in the zone 17.Etched mode for example can be anisotropy (anisotropic) reactive ion etch (RIE, reactive ion etch).In the etching process, the photoresist 18c has largely been nearly complete depletion, but yet have retained a hard shield 18b.Likewise, this etching step belongs to option, can omit and directly carry out the step of Fig. 8 C and 9C.

Then see Fig. 8 C and 9C; Oxide areas 14 is carried out oxide etching; Its mode for example can be used hydrofluoric acid vapor etching (HF vapor etch) or monolith substrate immersed in the acid tank and carry out Wet-type etching with buffer oxide etch (BOE, buffered oxide etch) mode.So, can obtain the microcomputer electric component desired, wherein the difference of Fig. 8 C and 9C is in the zone 100, and whether the top of micro electromechanical structure retains overcoat 18a and hard shielding 18b.If necessary, can be again with the removal of photoresistance etch process, and remove the outer hard shielding 18b in zone 100, its step will not be given unnecessary details.

Above technology is example with construction drawing 3 structures, but certainly also can be in order to the structure of construction drawing 5A, 5B, 6A, 6B etc.

Below the present invention is described to preferred embodiment, the above, be merely make those skilled in the art be easy to understand content of the present invention and, be not to be used for limiting interest field of the present invention.To those skilled in the art, when can in spirit of the present invention, thinking immediately and various equivalence variation.For example, except that Fig. 6 A, 6B, reach same purpose, the mode of various perforates can be arranged.And for example, spring can be other any structure except that two kinds of structures shown in Fig. 6 C.For another example, with silica example though the said metal of embodiment is example, dielectric material with aluminium, the present invention also can use copper and advanced low-k materials is made.Except that the above, also other has the possibility that various equivalences change.So all according to a notion of the present invention and spirit impartial for it a variation or modification, all should be included in the scope of claims of the present invention.

Claims

1. a same plane sensor is characterized in that, comprises:

One fixed structure, this fixed structure comprises fixed arm connected to one another and stiff end, and this fixed arm has the support end and the end that suspends, and support end is connected with stiff end, and the end that suspends is for suspending; And

One moving structure, this moving structure comprises body connected to one another and adjutage at least, this moving structure also includes extension body, is connected with body via adjutage,

Wherein, the support end of this fixed arm is held more near body than suspending.

2. same plane sensor as claimed in claim 1, wherein, this moving structure also comprises connecting portion and fixed part, and body is connected with fixed part via connecting portion, and this fixed part and the same substrate that is fixed in of fixed structure.

3. same plane sensor as claimed in claim 2, wherein, this connecting portion is a spring.

4. same plane sensor as claimed in claim 3, wherein, this spring has at least one tortuous place on its long direction.

5. same plane sensor as claimed in claim 1, wherein, this body has perforate.

6. same plane sensor as claimed in claim 1, wherein, the length at least one in length and breadth direction of this body is not continuous through cutting.

7. same plane sensor as claimed in claim 1 wherein, has perforate on this extension body.

8. same plane sensor as claimed in claim 1, wherein, this moving structure includes a plurality of bodies and a plurality of extension body, links into an integrated entity via adjutage.