CN1966548B - Polishing medium for chemical-mechanical polishing, and method of polishing substrate member - Google Patents
Polishing medium for chemical-mechanical polishing, and method of polishing substrate member Download PDFInfo
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- CN1966548B CN1966548B CN2006101418903A CN200610141890A CN1966548B CN 1966548 B CN1966548 B CN 1966548B CN 2006101418903 A CN2006101418903 A CN 2006101418903A CN 200610141890 A CN200610141890 A CN 200610141890A CN 1966548 B CN1966548 B CN 1966548B
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Abstract
This invention provides a polishing medium for chemical-mechanical polishing, comprising an oxidizing agent for a conductor, a protective-film-forming agent for protecting a metal surface, an acid, and. water; (1) the polishing medium having a pH of 3 or less, and the oxidizing agent being in a concentration of from 0.01 to 3% by weight, or (2) the polishing medium containing abrasive grains having an average particle diameter of 50 nm or less, and the abrasive grains having standard deviation of particle size distribution in a value of more than 5 nm.
Description
The application is to be on August 17th, 2000 applying date of original application, and application number is 200410048737.7, and denomination of invention is divided an application for the Chinese patent application of " cmp with the polishing of abrasive and substrate ".
Technical field
The present invention relates to be applicable to abrasive that the cmp that grinds in the formation cloth line procedures of semiconductor device is used and grind the method for substrate with its.
Technical background
In recent years, be accompanied by the highly integrated and high performance of semiconductor integrated circuit (following note is made LSI), developed novel trickle processing technology.Chemical mechanical milling method (following note is made CMP) is exactly wherein a kind of, be in LSI manufacturing process, particularly forming the interlayer dielectric in the multilayer wiring operation planarization, form metal plug, form in the buried wiring the frequent technology of utilizing.This technology is disclosed in as in No. 4944836 communique of United States Patent (USP).
Recently, in order to make the LSI high performance,, copper or copper alloy have been tried out as wiring material.Yet the frequent dry corrosion method of utilizing in the former formation aluminium alloy wiring is difficult to carry out trickle processing to copper or copper alloy.Mainly adopt so-called metallized thread (the ダ マ シ Application) method of knitting being pre-formed on the insulating film of ditch, piled up and imbed copper or copper alloy thin films, utilized CMP to remove copper or copper alloy thin films beyond the ditch portion, formed buried wiring.This technology is disclosed in as the spy and opens in the flat 2-278822 communique.
The general method of metal CMP such as copper or copper alloy, be that abrasive sheet is attached on the grinding plate (abrasive sheet) of figure, surface with abrasive dipping abrasive sheet, push the face of the formation metallic membrane of substrate, apply certain pressure (following note is made grinding pressure) from its back side, under this state, rotate grinding plate,, remove the metallic membrane of protuberance by the mechanical friction of abrasive and metallic membrane protuberance.
The abrasive that uses among the CMP is generally formed by oxygenant and abrasive material, also can add oxidized metal dissolving agent as required, protect and expand film formation agent.Utilize this CMP to carry out the basic mechanism of CMP with abrasive, think at first by oxygenant oxidation metallic film surface, by abrasive material this zone of oxidation is ground away again, the oxidation on metal surface layer of concave portion is not owing to can touch very much abrasive sheet, abrasive material can not produce ground effect, so when CMP carries out, removed the metal level of convex portion, formed smooth substrate surface.Be disclosed in " electrochemistry magazine " Journal ot Electrochemlcal Society about its detailed content) the 138th volume No. 11 (1991 distribution) on 3460-3464 pages or leaves.
In order to accelerate the grinding rate of CMP, it is effective adding oxidized metal dissolving agent.This can be construed to, and when the metal oxide microparticle by abrasive grinding is dissolved in the shape grinding agent (following note is corroded), has increased the effect of abrasive grinding.Yet when adding oxidized metal dissolving agent, the zone of oxidation of concave portion metallic film surface also is corroded (dissolving), and when exposing metallic film surface, oxygenant can film surface, further oxidized metal.When this process was carried out repeatedly, the corrosion of the metallic membrane of concave portion also can go on.Therefore, the surface of metal wiring middle body of imbedding after the grinding, (following note is done concavity corrosion (デ イ シ Application グ) and is impaired smooth effect as the hollow phenomenon as ware in appearance.
In order to prevent that phenomenon takes place here, in CMP further interpolation protective membrane formation agent in the metal grinding agent.Protective membrane forms agent and form protective membrane on the zone of oxidation of metallic film surface, can prevent that zone of oxidation from dissolving in abrasive.Can cut with abrasive material easily, and not reduce the grinding rate of CMP for this protective membrane, hope.
For concavity corrosion and the corrosion in the grinding that suppresses copper or copper alloy forms the high LSI wiring of reliability; promotion is as oxidized metal dissolving agent; can use aminoacetic acid or acid amides sulfuric acid such as glycine; form agent as protective membrane, can use the CMP abrasive of benzotriazole (following note BTA).This technology is documented in as the spy and opens in the flat 8-83780 communique.
Knit the metal of embolisms wirings (プ ラ グ) such as (ダ マ シ Application) wiring and formation tungsten imbeds in the formation at the metallized thread of what is called formation copper or copper alloy, when the grinding rate of the interlayer dielectric silicon dioxide film that forms beyond the inlet part during, produce the phenomenon of the cotton ginning (シ ニ Application グ) that is called the attenuation of wiring thickness at each interlayer dielectric near the grinding rate of metallic membrane.The result produces by increase of cloth line resistance and pattern density etc. and causes resistance deviation.For this reason, for the CMP abrasive, the relative metallic membrane that grinds, the grinding rate that requires so-called silicon dioxide film is little characteristic fully.Therefore, utilize acid to decompose the grinding rate that the negatively charged ion that produces can suppress silicon-dioxide, advocate the method for the PH of abrasive that make greater than pka-0.5.This technology is documented in as in No. 2819196 communique of Japanese Patent.
On the other hand, copper or lower floor such as copper alloy in wiring spread in interlayer dielectric in order to prevent copper, form barrier layer, as being formed by tantalum, tantalum alloy, tantalum nitride, other tantalum compound etc.Therefore, beyond the wiring portion of imbedding copper or copper alloy, need utilize CMP to remove the barrier layer that exposes.Yet, constitute the conductor of these barrier layers, because its hardness is higher than copper or copper alloy, the combination abrasive substance that copper or copper alloy are used, most cases are to can not get sufficient grinding rate.Therefore, 2 Ginding process that form by the 1st procedure that grinds copper or copper alloy and the 2nd procedure that grinds the barrier layer conductor have been studied.
Among the CMP as the barrier layer of the 2nd operation, need prevent to imbed the concavity corrosion of copper or copper alloy wiring portion,, think that the PH that reduces abrasive is a kind of negative effect for grinding rate and the corrosion speed that suppresses copper or copper alloy.
As tantalum, tantalum alloy and the tantalum compound (tantalum nitride) of barrier layer, chemical stabilization is difficult to corrosion, since the hardness height, easy mechanical mill unlike copper or copper alloy.For this reason, when improving abrasive hardness, on copper or copper alloy, produce sometimes and grind fault, form the bad reason of electroconductibility.When improving the particle concentration of abrasive material, can increase the grinding rate of silicon dioxide film, there is the so-called problem that produces cotton ginning.
Disclosure of the Invention
The purpose of this invention is to provide a kind of can suppress to produce spill burn into cotton ginning in the wiring of copper or copper alloy and grind fault, the high speed that realizes barrier layer under low abrasive concentration grinds, forms that the high metallic membrane of reliability imbeds that the CMP of pattern uses abrasive and with its Ginding process to substrate.
Present inventors have carried out deep research for reaching this purpose, found that, to grinding as conductor tantalum, tantalum alloy and the tantalum compound of barrier layer, under the occasion that PH is low and concentration oxygenant is low of abrasive, carry out easily, and so far finish the present invention.The 1st kind of abrasive that cmp is used that provides among the present invention contain these conductors oxygenant, the protective membrane of metallic surface is formed agent, acid and water, PH is below 3, and oxidant concentration is 0.01-3 weight %.The 1st kind of abrasive also can contain abrasive material.
When grinding barrier layer, improve abrasive hardness and make the copper alloy generation grind fault and form the bad reason of electroconductibility often, when improving the particle concentration of abrasive material, there is the grinding rate that increases silicon dioxide film again, produce the problem of so-called cotton ginning sometimes.
Present inventors find that to tantalum and tantalum alloy and tantalum nitride as barrier layer, the grinding of other tantalum compounds in low PH zone and suboxide agent concentration zone, is carried out easily.And, know when using this CMP to use abrasive that because oxidant concentration is in the enough low zone, generally the corrosion speed at low PH zone internal cause increase the becoming copper and copper alloy of problem causes the corrosion of wiring concavity, also can not form problem.
Present inventors find, in the grinding of the tantalum, tantalum alloy or the tantalum compound that are used as the barrier layer conductor, when abrasive size is excessive, the grinding rate of barrier layer can reduce and the grinding rate of silicon-dioxide can increase, and then, even abrasive size is very little, when the standard deviation of size distribution was too small, the grinding rate of silicon-dioxide also can increase.This phenomenon is remarkable especially when the abrasive low with PH, that oxidant concentration is low grinds tantalum, tantalum alloy or tantalum compound.
When using this abrasive, as can be known since oxidant concentration in enough low zone, generally the corrosion speed increase that becomes the copper and copper alloy of problem in low PH zone internal cause causes that the wiring concavity corrodes, and can not form problem yet, because abrasive concentration is low, corrodes also very little.
Therefore, the abrasive that provides among the present invention is the oxygenant that contains conductor, the protective membrane of metallic surface is formed the abrasive of agent, acid and water, and the median size that also contains abrasive material, this abrasive material is below 50nm, and the standard deviation value of size distribution is greater than 5nm.
This abrasive of the present invention, preferably PH is below 3, and the concentration of oxygenant is 0.01-3 weight %.By reducing PH and oxidant concentration, can suppress the generation of copper or copper alloy wiring concavity burn into cotton ginning and grinding fault, and can realize the high grinding rate of barrier layer with low abrasive concentration.
CMP abrasive of the present invention can contain water-soluble polymer, and the oxidant concentration of this moment is preferably 0.01-1.5 weight %.Select in the preferably following group of forming of water-soluble polymer at least a kind, that is, and polyacrylic acid or its salt, polymethyl acrylic acid or its salt, polyamic acid and salt thereof, polyacrylic acid amide, polyvinyl alcohol, polyvinylpyrrolidone.
The preferred organic acid of acid is preferably selected a kind at least from propanedioic acid, oxysuccinic acid, Tartaric acid, oxyacetic acid and citric acid.
The oxygenant of conductor is preferably selected a kind at least from hydrogen peroxide, nitric acid, periodic acid potassium, hypochlorous acid, ozone water.
Protective membrane forms agent, preferably selects at least from benzotriazole (BTA) and derivative thereof a kind (following note is made the BTA class).
Abrasive material is preferably selected a kind at least from silicon oxide, aluminum oxide, cerium oxide, titanium oxide, zirconium white, germanium oxide, silicon carbide, median size colloided silica or the present invention of colloidal alumina optimum below 50nm.The median size of abrasive material is preferably in below the 30nm, and the standard deviation of size distribution is preferably in more than the 10nm.That abrasive concentration is good is 0.05-10 weight %, 0.1-5 weight % more preferably, and especially good is 0.2～3 weight %.Preferably utilize the hydrolysis silicon alkoxide to make colloided silica, also can use water glass is made as raw material.
Greater than 1, and the grinding rate of tantalum or tantalum nitride and silicon dioxide film is than (Ta/SiO than (Ta/Cu, TaN/Cu) for CMP abrasive of the present invention, the grinding rate that preferably makes tantalum or tantalum nitride and copper (comprising copper alloy)
2, TaN/SiO
2) greater than 10.
, copper, copper alloy, cupric oxide are arranged and constitute the tantalum, tantalum alloy, tantalum compound (tantalum nitride) etc. of their barrier layer (for the layer of anti-copper atom diffusion) with the conductor (comprising semi-conductor) that abrasive grinds as the suitable CMP of the present invention of use.Provide in the present invention and used CMP abrasive of the present invention, grinding contains the Ginding process of the barrier layer of tantalum, tantalum alloy and tantalum compound (tantalum nitride etc.), and use CMP abrasive of the present invention, grind the Ginding process of the face that contains wiring layer (copper, copper alloy and/or their oxide compound) and its barrier layer (layer of anti-copper atom diffusion).
Description of drawings
Fig. 1 is the schematic illustration of substrate grinding step among the embodiment.
The optimal morphology that carries out an invention
Abrasive of the present invention, optimum grinding object is to form on the surface has the substrate of silicon-dioxide recess.Filling contains the substrate of barrier layer and copper or copper metallic membrane.Such substrate; for example obtain by following process; as shown in Figure 1; on silicon chip 10 (Fig. 1 (a)) surface, form silicon dioxide film 11 (Fig. 1 (b)); on this surface, form the protective film 12 (Fig. 1 (c)) of predetermined pattern; utilize dry corrosion on silicon dioxide film 11, to form recess 13; remove protective film (Fig. 1 (d)); utilize evaporation; the barrier layer 14 (Fig. 1 (e)) of metallic barrier films such as formation such as CVD tantalum; extending part with topped silicon dioxide film 11 surfaces and silicon chip 10; utilize evaporation again; plating or CVD make metal film forming formation wiring layers 15 (Fig. 1 (f)) such as copper in its surface.
The grinding rate that uses wiring layer (copper and/or copper alloy)/barrier layer is than enough big copper and copper alloy abrasive, when this substrate is carried out CMP, obtain barrier layer 14 exposing surfaces of substrate protuberance (that is the position of silica 11, is set), the desired conductive pattern (Fig. 1 (g)) that wiring layer (copper or tin-copper alloy film) 15 remains in recess.
When use can be ground this substrate with abrasive barrier layer 14 and the wiring layer 15 two-layer CMP that grind, as Fig. 1 (h)) shown in, the semiconductor substrate of silica 11 exposing surface obtained.
The 1st kind of CMP abrasive of the present invention; be the oxygenant that contains conductor, the protective membrane of metallic surface is formed the abrasive of agent, acid and water, adjust PH below 3, oxidant concentration is 0.01-3 weight %; as required, also can add water-soluble polymer, abrasive material.
When CMP played 3 with the PH of abrasive, the grinding rate of tantalum, tantalum alloy and/or tantalum compound was little.Addition by acid can be adjusted PH.Also can adjust by adding alkaline components such as ammonia, sodium hydroxide, halogenation tetramethyl-ammonium.
When the oxidant concentration of conductor during near 0.15 weight %, it is very big that the grinding rate of tantalum, tantalum alloy and/or tantalum compound reaches.Utilize oxygenant,, form the once oxidation layer that carries out mechanical mill easily, obtain very high grinding rate on electrically conductive film surfaces such as tantalum, tantalum alloy, tantalum compounds.
Say that generally PH was less than 3 o'clock, the corrosion speed of copper or tin-copper alloy film is big, and protective membrane forms agent and is difficult to suppress corrosion.Yet, among the present invention,, can suppress corrosion so protective membrane forms agent because the concentration of oxygenant is enough low.When oxidant concentration is excessive above 3 weight %, it is very big that the corrosion speed of copper or copper alloy becomes, not only be easy to generate the concavity corrosion phenomenon, and, on electrically conductive film surfaces such as tantalum, tantalum alloy, tantalum nitride, other tantalum compounds, formation causes grinding rate to reduce than the secondary oxidation layer of the more difficult grinding of once oxidation layer.When the concentration of oxygenant is lower than 0.01 weight %, owing to fully do not form zone of oxidation, so grinding rate diminishes phenomenon such as also can take place that tantalum film is peeled off.
The 1st kind of CMP abrasive of the present invention also can contain abrasive material, in order to improve dispersion stabilization, reduces and grinds the damage number of times, and its median size wishes to be preferably in below the 50nm below 100nm.
The 2nd kind of CMP abrasive of the present invention is to contain the conductor oxygenant, the protective membrane of metallic surface is formed the CMP abrasive of agent, acid and water, so contain below the median size 50nm and also the standard deviation of size distribution greater than the abrasive material of 5nm.The 2nd abrasive also preferably makes PH below 3 by adjustment, and the concentration of conductor oxygenant is 0.01～3 weight %.Also can add water-soluble polymer as required.The median size of abrasive material below 30nm, the standard deviation of its size distribution is greater than the abrasive material of 10nm, suitable especially the present invention.When median size was excessive above 50nm, the grinding rate of barrier tunic was very little, and the grinding rate of silicon dioxide film is very big.And find, even median size below 50nm, when the standard deviation of size distribution was lower than 5nm, the grinding rate of silicon dioxide film also was tending towards increasing.
The 1st kind or the 2nd kind of CMP of the present invention when containing water-soluble polymer, are preferably 0.01-1.5 weight % with the concentration of the conductor oxygenant in the abrasive.Because water-soluble polymer is adsorbed on the surface of tantalum, tantalum alloy, tantalum compound or its oxide film, diminishes so obtain the oxidant concentration scope of higher grinding rate.Particularly, so because water-soluble polymer is easy to be adsorbed on the grinding rate of nitride compound films such as nitrogenize tantalum film, titanium nitride on the surface of nitride compound films such as nitrogenize tantalum film, titanium nitride diminishes.On the other hand, water-soluble polymer has the effect that the metallic surface forms protective membrane, so improved holding property of planarization such as concavity corrosion and cotton ginning.
As conductor oxygenant of the present invention, hydrogen peroxide (H is arranged
2O
2) nitric acid, periodic acid potassium, hypochlorous acid, ozone water etc., wherein, hydrogen peroxide is best.Substrate is when containing the silicon substrate of unicircuit usefulness element, owing to do not wish to cause pollution by basic metal, alkaline-earth metal, halogenide etc., so preferably do not contain the oxygenant of nonvolatile component.Because ozone water is formed fierce in time the variation, so hydrogen peroxide is the most suitable.The substrate of applicable object is when not containing the glass substrate etc. of semiconductor element, even it is also harmless to contain the oxygenant of nonvolatile component.
As the acid of using among the present invention, preferably formic acid or organic acid (acetic acid, propionic acid, valeric acid, 2-methyl butyric acid, the n-caproic acid, 3,3-dimethyl butyric acid, 2-ethyl butyric acid, the 4-methylvaleric acid, the n-enanthic acid, 2 methyl caproic acid, n-is sad, 2 ethyl hexanoic acid, M-nitro benzoic acid, oxyacetic acid, Whitfield's ointment, R-Glyceric acid, oxalic acid, propanedioic acid, succsinic acid, Potenlini, hexanodioic acid, pimelic acid, toxilic acid, phthalandione, oxysuccinic acid, tartrate, Citric acid etc.), and then also can use their salt such as ammonia salt, sulfuric acid, nitric acid, ammonia, the ammonium salt class, for example, ammonium persulphate, ammonium nitrate, ammonium chloride, butyric acid etc. or their mixture etc.In these, obtain practical CMP grinding rate aspect from what is called and consider, preferably propanedioic acid, oxysuccinic acid, tartrate, oxyacetic acid and citric acid.
Protective membrane among the present invention forms agent; can from following material, select; promptly; benzotriazole (BTA), BTA derivative are (for example; benzotriazole-4 carboxylic acid, its methyl, ethyl, propyl group, butyl and octyl group ester etc. that hydrogen atom in the phenyl ring of BTA is replaced with methyl substituted tolytriazole, with carboxyl etc.), naphthalene triazole, naphthalene triazole derivative, or contain their mixture.
As the water-soluble polymer that uses among the present invention, polyacrylic acid is for example arranged, polyacrylic acid ammonia salt, polyacrylic acid sodium salt, polymethyl acrylic acid, polymethyl acrylic acid ammonia salt, sodium polymethacrylate salt, polyacrylic acid amide etc. will have the monomer of carboxyl as unitary polymkeric substance of basic comprising or basic salt, polyvinyl alcohol, polyvinylpyrrolidones etc. have the monomer of vinyl as the unitary polymkeric substance of basic comprising, when the substrate that is suitable for is a semiconductor integrated circuit with silicon substrate etc., owing to do not wish by basic metal, alkaline-earth metal, halogenide etc. cause pollution, so preferably sour or its ammonia salt.When substrate is glass substrate, without limits to it.By adding these water-soluble polymers, can improve by protective membrane and form the concavity corrosion that agent suppresses the corrosive effect generation.
In the present invention, greater than 1, and the grinding rate of tantalum or tantalum nitride and silicon-dioxide is than (Ta/SiO than (Ta/Cu, TaN/Cu) for the grinding rate that tantalum or tantalum nitride and copper (copper alloy) is provided
2, TaN/SiO
2) grind system greater than 10 CMP usefulness.
As previously mentioned; among the present invention; by making CMP use the PH of abrasive less than 3; make suboxide agent concentration (oxidant concentration is near 0.15 weight %); tantalum and tantalum alloy and tantalum nitride as barrier layer; and the grinding rate of other tantalum compounds can become very big; PH was less than 3 o'clock; the copper and copper alloy film corrosion speed become big; because oxidant concentration is enough low; so can form agent by protective membrane suppresses; if the colloided silica of the median size 50nm that the grinding rate of use silicon-dioxide diminishes; abrasive materials such as colloidal alumina; the grinding rate of tantalum or tantalum nitride and copper (copper-bearing alloy) is than (Ta/Cu; TaN/Cu) greater than 1; and the grinding rate of tantalum or tantalum nitride and silicon-dioxide is than (Ta/SiO
2, TaN/SiO
2) greater than 10.
As the abrasive material of CMP of the present invention with abrasive, can be any in the organism abrasive materials such as inorganics abrasive material, polystyrene, polyacrylic acid, polyvinyl chloride such as silicon oxide, aluminum oxide, cerium oxide, titanium oxide, zirconium white, germanium oxide, silicon carbide, but the dispersion stabilization in abrasive is fine, grinding damage (fault) number of times that is produced by CMP is seldom the time, preferably colloided silica, the colloidal alumina of median size below 50nm.The change of the grinding rate of barrier layer is big, the grinding rate change of silicon-dioxide hour, and median size is better below 30nm, and is especially good below 20nm.As colloided silica, for example can use by the ion-exchange of the hydrolysis of silicon alkoxide or water glass and make, as colloidal alumina, for example can use and make by the aluminum nitrate hydrolysis.
The 1st or 2CMP with the abrasive material addition in the abrasive, with respect to gross weight, that good is 0.01-10 weight %, more preferably 0.05-5 weight %.When this use level was lower than 0.01 weight %, the grinding rate when not containing abrasive material is big-difference too not, when surpassing 10 weight %, manyly also can not improve the CMP grinding rate again even add.
CMP abrasive of the present invention is specially adapted to (for example, the grinding of the conductor (comprising semi-conductor) of tantalum, tantalum alloy, tantalum compound (tantalum nitride etc.) of copper, copper alloy, cupric oxide and their barrier layer.
The use level of acid in the abrasive of the present invention, for oxygenant, acid, protective membrane formation agent, water-soluble polymer and the water of total amount 100g conductor, that good is 0.0001-0.05mol, more preferably 0.001-0.01mol.When this use level surpassed 0.05mol, the corrosion of copper or copper alloy was tending towards increasing.
The protective membrane of abrasive of the present invention forms the agent use level, and for oxygenant, acid, protective membrane formation agent, water-soluble polymer and the water of total amount 100g conductor, that good is 0.0001-0.01mol, more preferably 0.005-0.005mol.When this use level was lower than 0.0001mol, the corrosion of copper or copper alloy was tending towards increasing, and when surpassing 0.01mol, effect does not change.
Also can add water-soluble polymer among the present invention, the use level of water-soluble polymer, for oxygenant, acid, protective membrane formation agent, water-soluble polymer and the water of total amount 100g conductor, good is 0.001-0.5 weight %, more preferably 0.01-0.2 weight.When this use level is lower than 0.001 weight %, in suppressing the concavity corrosion, be tending towards not occurring forming with protective membrane the combined effect of agent, when surpassing 0.5 weight %, the grinding rate that is caused by CMP is tending towards reducing.
The method of using CMP of the present invention to grind substrate with abrasive be with CMP with on the abrasive sheet on the abrasive grinding plate, and contacted by abrasive surface, make by abrasive surface and abrasive sheet and do relative movement, the Ginding process that grinds.As milling apparatus, can use to have to keep having by clampers and the general milling apparatus that posts (motor of variable revolution is installed) grinding plate of abrasive sheet such as the semiconductor substrates of abrasive surface.As abrasive sheet, can use general non-woven fabrics, polyurathamc, porous fluoride resin etc., there is not particular restriction.Grinding condition also without limits, the speed of rotation of grinding plate does not fly out with substrate and is as the criterion, and is preferably in the following low speed rotation of 200rpm.To have the pressure of being pressed to abrasive sheet by the semiconductor substrate of abrasive surface (by grinding film), that good is 9.8-98.1kpa (100-1000gf/cm
2), satisfy unilateral interior homogeneity and pattern flatness, more preferably 9.8-49.0kpa (100-500gf/cm in order to make grinding rate
2).During the grinding, continuously CMP is supplied with abrasive sheet with abrasive with pump.This feed rate without limits, but the most handy abrasive covers the surface of abrasive sheet frequently.After grind finishing, with semiconductor substrate with running water wash after clean, the most handy rotatory drier etc. is disposed attached to behind the water droplet on the semiconductor substrate, carries out drying again.
Embodiment
Below utilize embodiment to specify the present invention.The present invention is not limited by these embodiment.
(1) modulates the abrasive that cmp is used
As shown in table 1; to sour 0.4 weight %, (embodiment 1 does not add abrasive material; embodiment 2-9 adds 1 weight part; embodiment 10-13 adds 1 weight %), water-soluble polymer 0.05 weight part (embodiment 4 just; 6; 7 add) and protective membrane form among agent (BTA) the 0.2 weight %; add entry (embodiment 1-9 is that 98.85 weight parts, embodiment 10-13 are 97.9 weight %); dissolve; oxygenant as conductor; add aquae hydrogenii dioxidi (reagent superfine, 30% aqueous solution), gains are as the CMP abrasive.The abrasive material that adds is that to make the latter made median size of tetrem oxosilane hydrolysis in ammonia solution be the colloided silica of 20-60nm.The oxysuccinic acid that uses and the pka of oxyacetic acid are respectively 3.2.
Table 1
| Embodiment | Acid | Concentration of hydrogen peroxide (weight %) | pH | Abrasive material (colloided silica) | Water-soluble polymer | |
| Particle diameter (nm) | Size-grade distribution standard deviation (nm) | |||||
| 1 | Oxyacetic acid | 0.15 | 2.58 | - | - | Do not have |
| 2 | Oxysuccinic acid | 0.15 | 2.50 | 20 | 10 | Do not have |
| 3 | Oxysuccinic acid | 1.5 | 2.49 | 20 | 10 | Do not have |
| 4 | Oxysuccinic acid | 0.15 | 2.80 | 20 | 10 | Ammonium polyacrylate |
| 5 | Oxyacetic acid | 0.15 | 2.58 | 20 | 10 | Do not have |
| 6 | Oxyacetic acid | 0.15 | 2.95 | 20 | 10 | Ammonium polyacrylate |
| 7 | Oxysuccinic acid | 1.8 | 2.76 | 20 | 10 | Ammonium polyacrylate |
| 8 | Oxysuccinic acid | 3.3 | 2.45 | 20 | 10 | Do not have |
| 9 | Oxysuccinic acid | 0.15 | 3.25 | 20 | 10 | Do not have |
| 10 | Oxysuccinic acid | 0.15 | 2.50 | 25 | 10 | Do not have |
| 11 | Oxysuccinic acid | 0.15 | 2.50 | 40 | 14 | Do not have |
| 12 | Oxysuccinic acid | 0.15 | 2.52 | 60 | 13 | Do not have |
| 13 | Oxysuccinic acid | 0.15 | 2.51 | 30 | 5 | Do not have |
(2) grind
The CMP that use obtains implements CMP with abrasive.Grinding condition is as follows.
Substrate:
Form the silicon substrate of the thick tantalum film of 200nm
Form the silicon substrate of the thick nitrogenize tantalum film of 100nm
Form the silicon substrate of 1 μ m thick silicon dioxide film
Form the silicon substrate of 1 thick copper film
Abrasive sheet: foaming polyurethane resin with separated foam
Grinding pressure: 250gf/cm
2
The speed of relative movement of substrate and grinding plate: 18m/ minute
(3) grinding object assessment item
To implementing the grinding object of CMP, with regard to following every the evaluation.
The grinding rate that CMP forms:
The film thickness of being tried to achieve film CMP front and back by the resistance value conversion is poor.
Corrosion speed:
It is poor with the copper layer thickness before and after the dipping of abrasive to be tried to achieve at 25 ℃ of cmps that stir with 100rpm by the resistance value conversion.
The concavity etching extent
In silicon-dioxide, form the dark ditch of 0.5 μ m, utilize known sputtering method to form the thick nitrogenize tantalum film of 50nm, as barrier layer, it is cured to form copper with sputtering method equally, utilizes known thermal treatment, and the silicon substrate of imbedding is used as substrate, carrying out 2 times grinds, with contact pin type step difference meter,, obtain the wiring metal part film reduction of insulating film part relatively from the wide wiring metal of 100 μ m portion, the wide insulation membranous part of 100 μ m side by side the surface shape of drafting department of formation linear alternately.The 1st abrasive of using as copper, the abrasive that use is used than enough big copper and copper alloy with respect to the copper grinding rate of tantalum nitride, grind after 1 grinding, be made into substrate sample, on the insulation membranous part, expose the concavity etching extent of measuring under the state of barrier layer and reach 50nm, use above-mentioned cmp to carry out grinding for 2 times till the insulation membranous part does not have barrier layer with abrasive.
The cotton ginning amount
Surface shape to the linear drafting department of the wide 45 μ m of wiring metal portion that form on substrate at above-mentioned concavity corrosion evaluation, beam overall 2.5mm that the wide 5 μ m of insulation membranous part replace flat raft, utilize contact pin type step difference meter to measure, obtain film reduction with respect near the insulating film part pattern central authorities of the insulating film zone portion of linear pattern periphery.Be made into substrate sample after 1 grinding, exposing the cotton ginning amount of measuring under the state of barrier layer on the insulation membranous part is 20nm, uses above-mentioned cmp to carry out grinding for 2 times till not having barrier layer on the insulating film part with abrasive.
(4) evaluation result
The grinding rate that is formed by CMP among each embodiment is shown in table 2.Concavity etching extent and cotton ginning amount are shown in table 3.
Table 2
| Embodiment | CMP grinding rate (nm/ branch) | Copper corrosion speed (nm/ branch) | |||
| Copper | Tantalum | Tantalum nitride | Silicon-dioxide | ||
| 1 | 4.0 | 5.0 | 0 | 0.5 | |
| 2 | 36.2 | 54.7 | 0.8 | 0.8 | |
| 3 | 24.9 | 44.9 | 1.3 | 3.2 | |
| 4 | 34.9 | 24.9 | 1.2 | 0.3 | |
| 5 | 33.0 | 61.5 | 1.3 | 0.7 | |
| 6 | 20.0 | 25.0 | 1.3 | 0.6 | |
| 7 | 1.1 | 5.5 | 1.7 | 0.4 | |
| 8 | 10.5 | 17.3 | 1.2 | 6.7 | |
| 9 | 2.0 | 3.0 | 0.7 | 0.1 | |
| 10 | 11.4 | 36.2 | 54.7 | 0.8 | |
| 11 | 3.2 | 28.8 | 43.2 | 0.8 | |
| 12 | 13.0 | 22.0 | 43.4 | 6.7 | |
| 13 | 23.4 | 30.4 | 57.7 | 9.5 |
Table 3
| Embodiment | |||||||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | |
| Concavity etching extent (nm) | 40 | 55 | 70 | 45 | 55 | 45 | 65 | 100 | 55 | 40 | 40 | 60 | 55 |
| Cotton ginning amount (nm) | 20 | 30 | 35 | 30 | 35 | 30 | 70 | 55 | 70 | 20 | 20 | 60 | 100 |
Embodiment 1-13 has obtained good concavity corrosion and cotton ginning characteristic.Particularly oxidant concentration be 0.01-3 weight %, PH at the embodiment 1-6 below 3, the grinding rate of tantalum and tantalum nitride is very big, concavity etching extent, cotton ginning amount are all very little, and be desirable especially.Among the embodiment 10,11, because the grinding rate of the tantalum nitrogenize tantalum film of barrier layer conductor is very big, the grinding rate of silicon dioxide film is smaller, so obtained good concavity corrosion and cotton ginning characteristic.
Particularly use water-soluble polymer, oxidant concentration is the embodiment 4,6 in the 0.01-1.5 weight % scope, compares with the more embodiment 7 of oxygenant addition (1.8 weight %), and is fine, and concavity etching extent, cotton ginning amount are very little.When using water-soluble polymer, the concentration of oxygenant preferably is taken as 0.01-1.5 weight %, addition than it more for a long time, the grinding rate of tantalum and tantalum nitride is tending towards reducing, the increase of cotton ginning amount.
Oxidant concentration below 3 weight %, PH is at the embodiment below 32, the embodiment 8 that surpasses 3 weight % with oxidant concentration compares, the corrosion speed of copper is slow, surpass 3 embodiment 9 compares with PH, the grinding rate of tantalum and tantalum nitride is accelerated, because concavity etching extent, cotton ginning amount are very little, so very desirable.
The embodiment 12 that embodiment 10,11 and abrasive size are big compares, and the grinding rate of barrier tunic (particularly tantalum film) grinding rate very fast, silicon dioxide film is very little, and is very good with regard to concavity corrosion and cotton ginning characteristic aspect.The embodiment 13 that embodiment 10,11 and size-grade distribution standard deviation are little compares, and the grinding rate of barrier tunic (particularly tantalum film) is identical, and the grinding rate of silicon dioxide film is very little, so concavity corrosion and cotton ginning characteristic good.
Industrial application
As mentioned above, according to the present invention, can effectively grind tantalum as barrier layer, tantalum alloy, tantalum compound etc., and can suppress the concavity burn into cotton ginning of copper or copper alloy wiring, grind the generation of fault, can form the high pattern of imbedding metal film of reliability.
Claims (36)
1. a cmp abrasive is characterized in that,
Contain abrasive material, conductor oxygenant, the protective membrane of metallic surface is formed agent, acid and water,
Above-mentioned cmp is 2.45～3 with the pH of abrasive,
The median size of above-mentioned abrasive material below 50nm,
The size distribution standard deviation value of above-mentioned abrasive material is greater than 5nm.
2. according to the cmp abrasive of claim 1 record, the oxidant concentration that it is characterized in that above-mentioned conductor is 0.01-3 weight %.
3. according to the cmp abrasive of claim 1 record, it is characterized in that above-mentioned abrasive material is at least a kind that selects from silicon oxide, aluminum oxide, cerium oxide, titanium oxide, zirconium white and germanium oxide.
4. according to the cmp abrasive of claim 3 record, it is characterized in that above-mentioned abrasive material is colloided silica or colloidal alumina.
5. according to the cmp abrasive of each record among the claim 1-4, the use level that it is characterized in that above-mentioned abrasive material is 0.1-5 weight %.
6. according to the cmp abrasive of claim 1 record, it is characterized in that also containing water-soluble polymer.
7. according to the cmp abrasive of claim 6 record, it is characterized in that above-mentioned water-soluble polymer is at least a kind that selects from the group that polyacrylic acid, polyacrylate, polymethyl acrylic acid, poly-methyl acrylate, polyamic acid, polyamic acid salt, polyacrylic acid amide, polyvinyl alcohol and polyvinylpyrrolidone are formed.
8. according to the cmp abrasive of claim 6 or 7 records, the concentration that it is characterized in that the oxygenant of above-mentioned conductor is 0.01-1.5 weight %.
9. according to the cmp abrasive of claim 1 record, it is characterized in that above-mentioned acid is organic acid.
10. according to the cmp abrasive of claim 9 record, it is characterized in that above-mentioned acid is at least a kind that selects from propanedioic acid, oxysuccinic acid, tartrate, oxyacetic acid and citric acid.
11., it is characterized in that it is select at least a that said protection film forms agent from the benzotriazole or derivatives thereof according to the cmp abrasive of claim 1 record.
12. according to the cmp abrasive of claim 1 record, the oxygenant that it is characterized in that above-mentioned conductor is at least a kind that selects from hydrogen peroxide, nitric acid, periodic acid potassium, hypochlorous acid and ozone water.
13. the cmp abrasive according to claim 1 record is characterized in that above-mentioned conductor is at least a kind that selects from copper, copper alloy, copper oxide and copper alloy oxide compound.
14., it is characterized in that above-mentioned conductor is the barrier layer that prevents the copper atom diffusion according to the cmp abrasive of claim 1 record.
15. the cmp abrasive according to claim 14 record is characterized in that above-mentioned barrier layer contains tantalum, tantalum alloy or tantalum compound.
16. the cmp abrasive according to claim 1 record is characterized in that pH is 2.49-2.95.
17. the cmp abrasive according to claim 1 record is characterized in that,
The grinding rate of tantalum and copper or copper alloy than Ta/Cu greater than 1,
The grinding rate of tantalum nitride and copper or copper alloy than TaN/Cu greater than 1.
18. the cmp abrasive according to claim 1 record is characterized in that,
Tantalum compares Ta/SiO with the grinding rate of silicon-dioxide
2Greater than 10,
Tantalum nitride compares TaN/SiO with the grinding rate of silicon-dioxide
2Greater than 10.
19. the Ginding process of a substrate is characterized in that, for the face that contains the barrier layer that comprises tantalum, tantalum alloy or tantalum compound, uses cmp to grind with abrasive,
Described cmp with abrasive contain abrasive material, conductor oxygenant, the protective membrane of metallic surface is formed agent, acid and water; and pH is 2.45～3; the median size of above-mentioned abrasive material is below 50nm, and the size distribution standard deviation value of above-mentioned abrasive material is greater than 5nm.
20. according to the Ginding process of the substrate of claim 19 record, the oxidant concentration that it is characterized in that above-mentioned conductor is 0.01-3 weight %.
21. the Ginding process according to the substrate of claim 19 record is characterized in that above-mentioned abrasive material is at least a kind that selects from silicon oxide, aluminum oxide, cerium oxide, titanium oxide, zirconium white and germanium oxide.
22. the Ginding process according to the substrate of claim 21 record is characterized in that above-mentioned abrasive material is colloided silica or colloidal alumina.
23. according to the Ginding process of the substrate of each record among the claim 19-22, the use level that it is characterized in that above-mentioned abrasive material is 0.1-5 weight %.
24. the Ginding process according to the substrate of claim 19 record is characterized in that also containing water-soluble polymer.
25. the Ginding process according to the substrate of claim 24 record is characterized in that above-mentioned water-soluble polymer is at least a kind that selects from the group that polyacrylic acid, polyacrylate, polymethyl acrylic acid, poly-methyl acrylate, polyamic acid, polyamic acid salt, polyacrylic acid amide, polyvinyl alcohol and polyvinylpyrrolidone are formed.
26. according to the Ginding process of claim 24 or 25 substrates of putting down in writing, the concentration that it is characterized in that the oxygenant of above-mentioned conductor is 0.01-1.5 weight %.
27. the Ginding process according to the substrate of claim 19 record is characterized in that above-mentioned acid is organic acid.
28. the Ginding process according to the substrate of claim 27 record is characterized in that above-mentioned acid is at least a kind that selects from propanedioic acid, oxysuccinic acid, tartrate, oxyacetic acid and citric acid.
29. the Ginding process according to the substrate of claim 19 record is characterized in that it is select at least a that said protection film forms agent from the benzotriazole or derivatives thereof.
30. according to the Ginding process of the substrate of claim 19 record, the oxygenant that it is characterized in that above-mentioned conductor is at least a kind that selects from hydrogen peroxide, nitric acid, periodic acid potassium, hypochlorous acid and ozone water.
31. the Ginding process according to the substrate of claim 19 record is characterized in that above-mentioned conductor is at least a kind that selects from copper, copper alloy, copper oxide and copper alloy oxide compound.
32. the Ginding process according to the substrate of claim 19 record is characterized in that above-mentioned conductor is the barrier layer that prevents the copper atom diffusion.
33. the Ginding process according to the substrate of claim 32 record is characterized in that above-mentioned barrier layer contains tantalum, tantalum alloy or tantalum compound.
34. the Ginding process according to the substrate of claim 19 record is characterized in that pH is 2.49-2.95.
35. the Ginding process according to the substrate of claim 19 record is characterized in that,
The grinding rate of tantalum and copper or copper alloy than Ta/Cu greater than 1,
The grinding rate of tantalum nitride and copper or copper alloy than TaN/Cu greater than 1.
36. the Ginding process according to the substrate of claim 19 record is characterized in that,
Tantalum compares Ta/SiO with the grinding rate of silicon-dioxide
2Greater than 10,
Tantalum nitride compares TaN/SiO with the grinding rate of silicon-dioxide
2Greater than 10.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1999230930 | 1999-08-17 | ||
| JP23093099 | 1999-08-17 | ||
| JP1999-230930 | 1999-08-17 | ||
| JP1999308665 | 1999-10-29 | ||
| JP1999-308665 | 1999-10-29 | ||
| JP30866599 | 1999-10-29 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 00811731 Division CN1203529C (en) | 1999-08-17 | 2000-08-17 | Polishing compound for chemimachanical polishing and method for polishing substrate |
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| CN1966548A CN1966548A (en) | 2007-05-23 |
| CN1966548B true CN1966548B (en) | 2011-03-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 00811731 Expired - Lifetime CN1203529C (en) | 1999-08-17 | 2000-08-17 | Polishing compound for chemimachanical polishing and method for polishing substrate |
| CN2006101418903A Expired - Lifetime CN1966548B (en) | 1999-08-17 | 2000-08-17 | Polishing medium for chemical-mechanical polishing, and method of polishing substrate member |
| CN 200410048737 Pending CN1626567A (en) | 1999-08-17 | 2000-08-17 | Polishing compound for chemimachanical polishing and method for polishing substrate |
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| CN 00811731 Expired - Lifetime CN1203529C (en) | 1999-08-17 | 2000-08-17 | Polishing compound for chemimachanical polishing and method for polishing substrate |
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| CN 200410048737 Pending CN1626567A (en) | 1999-08-17 | 2000-08-17 | Polishing compound for chemimachanical polishing and method for polishing substrate |
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| JP4336550B2 (en) * | 2003-09-09 | 2009-09-30 | 花王株式会社 | Polishing liquid kit for magnetic disk |
| WO2007055278A1 (en) * | 2005-11-11 | 2007-05-18 | Hitachi Chemical Co., Ltd. | Polishing agent for silicon oxide, liquid additive, and method of polishing |
| US7820067B2 (en) * | 2006-03-23 | 2010-10-26 | Cabot Microelectronics Corporation | Halide anions for metal removal rate control |
| TWI614093B (en) * | 2013-01-04 | 2018-02-11 | 福吉米股份有限公司 | Polishing composition, alloy material, method for polishing alloy material, and method for producing alloy material |
| CN104152107B (en) * | 2013-05-13 | 2016-08-17 | 深圳清华大学研究院 | Ceramic material grinding agent |
| US9982351B1 (en) * | 2017-01-31 | 2018-05-29 | GM Global Technology Operations LLC | Chemical mechanical polishing for improved contrast resolution |
| CN106878912A (en) * | 2017-03-03 | 2017-06-20 | 瑞声科技(新加坡)有限公司 | The method of the oxide layer mat surface planarization of Electret Condencer Microphone semi-finished product |
| SG10201904669TA (en) | 2018-06-28 | 2020-01-30 | Kctech Co Ltd | Polishing Slurry Composition |
| US20200198090A1 (en) * | 2018-12-13 | 2020-06-25 | Xia Tai Xin Semiconductor (Qing Dao) Ltd. | Cmp apparatus and method of performing ceria-based cmp process |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4789648A (en) * | 1985-10-28 | 1988-12-06 | International Business Machines Corporation | Method for producing coplanar multi-level metal/insulator films on a substrate and for forming patterned conductive lines simultaneously with stud vias |
-
2000
- 2000-08-17 CN CN 00811731 patent/CN1203529C/en not_active Expired - Lifetime
- 2000-08-17 CN CN2006101418903A patent/CN1966548B/en not_active Expired - Lifetime
- 2000-08-17 CN CN 200410048737 patent/CN1626567A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4789648A (en) * | 1985-10-28 | 1988-12-06 | International Business Machines Corporation | Method for producing coplanar multi-level metal/insulator films on a substrate and for forming patterned conductive lines simultaneously with stud vias |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1371528A (en) | 2002-09-25 |
| CN1966548A (en) | 2007-05-23 |
| CN1626567A (en) | 2005-06-15 |
| CN1203529C (en) | 2005-05-25 |
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