JP2004289170A - Cerium oxide polishing agent and method of polishing substrate - Google Patents
Cerium oxide polishing agent and method of polishing substrate Download PDFInfo
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- JP2004289170A JP2004289170A JP2004140115A JP2004140115A JP2004289170A JP 2004289170 A JP2004289170 A JP 2004289170A JP 2004140115 A JP2004140115 A JP 2004140115A JP 2004140115 A JP2004140115 A JP 2004140115A JP 2004289170 A JP2004289170 A JP 2004289170A
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- 229910000420 cerium oxide Inorganic materials 0.000 title claims abstract description 75
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 title claims abstract description 75
- 238000005498 polishing Methods 0.000 title claims abstract description 62
- 239000000758 substrate Substances 0.000 title claims description 35
- 239000003795 chemical substances by application Substances 0.000 title description 6
- 238000007517 polishing process Methods 0.000 title description 2
- 239000002245 particle Substances 0.000 claims abstract description 94
- 238000000034 method Methods 0.000 claims description 23
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 239000002270 dispersing agent Substances 0.000 claims description 7
- 239000002002 slurry Substances 0.000 abstract description 41
- 238000005229 chemical vapour deposition Methods 0.000 abstract description 2
- 230000037390 scarring Effects 0.000 abstract 1
- 239000000843 powder Substances 0.000 description 22
- 239000004065 semiconductor Substances 0.000 description 21
- 239000011164 primary particle Substances 0.000 description 19
- 238000005259 measurement Methods 0.000 description 12
- 230000003287 optical effect Effects 0.000 description 12
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 12
- 239000011802 pulverized particle Substances 0.000 description 12
- 238000002360 preparation method Methods 0.000 description 11
- 238000002441 X-ray diffraction Methods 0.000 description 9
- 239000011521 glass Substances 0.000 description 9
- 238000010298 pulverizing process Methods 0.000 description 9
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 7
- 238000009826 distribution Methods 0.000 description 7
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 7
- 229920000058 polyacrylate Polymers 0.000 description 7
- 238000003991 Rietveld refinement Methods 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 6
- 229910021641 deionized water Inorganic materials 0.000 description 6
- 229910052697 platinum Inorganic materials 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- -1 Na and K Chemical class 0.000 description 4
- 239000004744 fabric Substances 0.000 description 4
- 238000007561 laser diffraction method Methods 0.000 description 4
- 238000004062 sedimentation Methods 0.000 description 4
- 238000004438 BET method Methods 0.000 description 3
- 229910052684 Cerium Inorganic materials 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 3
- 150000001785 cerium compounds Chemical class 0.000 description 3
- KHSBAWXKALEJFR-UHFFFAOYSA-H cerium(3+);tricarbonate;hydrate Chemical compound O.[Ce+3].[Ce+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O KHSBAWXKALEJFR-UHFFFAOYSA-H 0.000 description 3
- 238000004518 low pressure chemical vapour deposition Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 3
- 238000001132 ultrasonic dispersion Methods 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 241000403354 Microplus Species 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 2
- 239000003082 abrasive agent Substances 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000008119 colloidal silica Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 239000002178 crystalline material Substances 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 150000002367 halogens Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 239000005304 optical glass Substances 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 239000012495 reaction gas Substances 0.000 description 2
- 239000010980 sapphire Substances 0.000 description 2
- 229910052594 sapphire Inorganic materials 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000000733 zeta-potential measurement Methods 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 1
- BFSVOASYOCHEOV-UHFFFAOYSA-N 2-diethylaminoethanol Chemical compound CCN(CC)CCO BFSVOASYOCHEOV-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- UEEJHVSXFDXPFK-UHFFFAOYSA-N N-dimethylaminoethanol Chemical compound CN(C)CCO UEEJHVSXFDXPFK-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- LHIJANUOQQMGNT-UHFFFAOYSA-N aminoethylethanolamine Chemical compound NCCNCCO LHIJANUOQQMGNT-UHFFFAOYSA-N 0.000 description 1
- 239000003945 anionic surfactant Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical group Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
Landscapes
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Abstract
Description
本発明は、酸化セリウム研磨剤及び基板の研磨法に関する。 The present invention relates to a cerium oxide abrasive and a method for polishing a substrate.
従来、半導体装置の製造工程において、プラズマ−ＣＶＤ、低圧−ＣＶＤ等の方法で形成されるＳｉＯ２絶縁膜等無機絶縁膜層を平坦化するための化学機械研磨剤として、コロイダルシリカ系の研磨剤が一般的に検討されている。コロイダルシリカ系の研磨剤は、シリカ粒子を四塩化珪酸を熱分解する等の方法で粒成長させ、アルカリ溶液でｐＨ調整を行って製造している。しかしながら、この様な研磨剤は無機絶縁膜の研磨速度が充分な速度を持たず、実用化には低研磨速度という技術課題がある。 2. Description of the Related Art A colloidal silica-based polishing agent has been conventionally used as a chemical mechanical polishing agent for planarizing an inorganic insulating film layer such as an SiO 2 insulating film formed by a method such as plasma-CVD or low-pressure CVD in a semiconductor device manufacturing process. Are generally considered. Colloidal silica-based abrasives are produced by growing silica particles by a method such as thermal decomposition of silicic acid tetrachloride and adjusting the pH with an alkaline solution. However, such a polishing agent does not have a sufficient polishing rate for the inorganic insulating film, and there is a technical problem of a low polishing rate for practical use.
一方、フォトマスクやレンズ等のガラス表面研磨として、酸化セリウム研磨剤が用いられている。酸化セリウム粒子は、シリカ粒子やアルミナ粒子に比べ硬度が低く、したがって研磨表面に傷が入りにくいことから仕上げ鏡面研磨に有用である。また、酸化セリウムは強い酸化剤として知られるように、化学的活性な性質を有している。この利点を活かし、絶縁膜用化学機械研磨剤への適用が有用である。しかしながら、ガラス表面研磨用酸化セリウム研磨剤は、不純物を多く含有するためそのまま半導体用研磨剤として適用することはできない。さらに、ガラス表面研磨用酸化セリウム研磨剤をそのまま無機絶縁膜研磨に適用すると、酸化セリウム粒子径（一次粒子や凝集粒子）が大きく、そのため絶縁膜表面に目視で観察できる研磨傷が入ってしまう。 On the other hand, cerium oxide abrasives have been used for polishing glass surfaces of photomasks, lenses, and the like. Cerium oxide particles have a lower hardness than silica particles and alumina particles and are therefore less likely to scratch the polished surface, and thus are useful for finish mirror polishing. Cerium oxide also has chemically active properties, as is known as a strong oxidizing agent. Taking advantage of this advantage, application to a chemical mechanical polishing agent for an insulating film is useful. However, a cerium oxide abrasive for polishing a glass surface contains a large amount of impurities, and therefore cannot be directly used as an abrasive for semiconductors. Further, when the cerium oxide abrasive for polishing the glass surface is applied to the polishing of the inorganic insulating film as it is, the cerium oxide particle diameter (primary particles or aggregated particles) is large, and thus the surface of the insulating film has polishing scratches that can be visually observed.
本発明は、ＳｉＯ２絶縁膜等の被研磨面を傷なく高速に研磨することが可能な酸化セリウム研磨剤および基板の研磨法を提供するものである。 The present invention provides a cerium oxide abrasive and a method of polishing a substrate, which can polish a surface to be polished such as a SiO 2 insulating film at high speed without scratches.
本発明の酸化セリウム研磨剤は、酸化セリウム粒子、分散剤、及び水を含むものである。酸化セリウムは炭酸塩、硝酸塩、硫酸塩、しゅう酸塩等のセリウム化合物を焼成または溶解−酸化することによって得られる。本発明の酸化セリウム研磨剤を構成する酸化セリウム粒子は、５００ｎｍ以上の粒子径の含有量が全酸化セリウム粒子の３〜４０体積％のもので、高速研磨が可能で研磨傷を防止できる。粒子径の中央値が１５０〜４５０ｎｍであることが好ましい。酸化セリウム粒子の粒子径は、レーザー回折法（例えば測定装置、Ｍａｌｖｅｒｎ Ｉｎｓｔｒｕｍｅｎｔｓ社製 Ｍａｓｔｅｒｓｉｚｅｒ Ｍｉｃｒｏｐｌｕｓ、光源Ｈｅ−Ｎｅレーザー、粒子の屈折率１．９２８５、吸収０で測定）で測定する。中央値は、体積粒子径分布の中央値であり、粒子径の細かいものからその粒子の体積割合を積算していき５０％になったときの粒子径を意味する。すなわち、ある区間Δの粒子径の範囲に体積割合Ｖｉ％の量の粒子が存在するとき、区間Δの平均粒子径をｄｉとすると粒子径ｄｉの粒子がＶｉ体積％存在するとする。粒子径ｄｉの小さい方から粒子の存在割合Ｖｉ（体積％）を積算していき、Ｖｉ＝５０％になったときのｄｉを中央値とする。酸化セリウム研磨剤中の酸化セリウム粒子は、９９体積％以上が３０００ｎｍ以下であることが好ましい。本発明の基板の研磨法は、上記の酸化セリウム研磨剤で所定の基板、例えばＳｉＯ２絶縁膜が形成された基板で研磨することを特徴とするものである。本発明は、粒子径を制御した酸化セリウム粒子を含む酸化セリウム研磨剤が、ＳｉＯ２絶縁膜等の被研磨面を傷なく高速に研磨することを見い出したことによりなされたものである。 The cerium oxide abrasive of the present invention contains cerium oxide particles, a dispersant, and water. Cerium oxide is obtained by calcining or dissolving and oxidizing cerium compounds such as carbonate, nitrate, sulfate and oxalate. The cerium oxide particles constituting the cerium oxide abrasive of the present invention have a particle diameter of 500 nm or more in a content of 3 to 40% by volume of the total cerium oxide particles, and can perform high-speed polishing and prevent polishing scratches. It is preferable that the median value of the particle diameter is 150 to 450 nm. The particle diameter of the cerium oxide particles is measured by a laser diffraction method (for example, a measuring device, Mastersizer Microplus manufactured by Malvern Instruments, a light source He-Ne laser, a refractive index of the particles is 1.9285, and the absorption is measured by zero absorption). The median value is the median value of the volume particle size distribution, and means the particle size when the volume ratio of the particles is integrated from the finer particle size to 50%. That is, when particles having an amount of volume ratio Vi% exist in the range of the particle diameter of a certain section Δ, if the average particle diameter of the section Δ is di, it is assumed that particles of the particle diameter di exist by Vi% by volume. The existence ratio Vi (volume%) of the particles is integrated from the smaller particle diameter di, and di when Vi = 50% is set as the median value. It is preferable that 99% by volume or more of the cerium oxide particles in the cerium oxide abrasive is 3000 nm or less. The substrate polishing method of the present invention is characterized in that a predetermined substrate, for example, a substrate on which an SiO 2 insulating film is formed is polished with the cerium oxide abrasive. The present invention has been made based on the finding that a cerium oxide abrasive containing cerium oxide particles having a controlled particle diameter polish a surface to be polished such as a SiO 2 insulating film at high speed without damage.
本発明の研磨剤により、ＳｉＯ２絶縁膜等の被研磨面を傷なく高速に研磨することが可能となる。 The polishing agent of the present invention enables a surface to be polished such as an SiO 2 insulating film to be polished at high speed without damage.
本発明の酸化セリウム研磨剤を構成する酸化セリウム粒子は、粒子径５００ｎｍ以上の含有量が５〜４０体積％であり、粒子径の中央値が１５０〜４５０ｎｍであることが好ましい。本発明の酸化セリウム研磨剤は、粒子径５００ｎｍ以上の含有量が５〜４０体積％とサブミクロンの粒子が多いために、自然沈降で測定すると測定時間が１か月以上となるため、沈降測定の場合は、遠心沈降法が好ましい。酸化セリウム研磨剤中の酸化セリウム粒子は、９９体積％以上が３０００ｎｍ以下であることが好ましい。また半導体チップ研磨に使用することから、アルカリ金属およびハロゲン類の含有率は、１０ｐｐｍ以下に抑えることが好ましい。 The cerium oxide particles constituting the cerium oxide abrasive of the present invention preferably have a content of a particle diameter of 500 nm or more of 5 to 40% by volume and a median particle diameter of 150 to 450 nm. The cerium oxide abrasive of the present invention has a content of 5 to 40% by volume of submicron particles having a particle diameter of 500 nm or more, and the measurement time is 1 month or more when measured by natural sedimentation. In this case, centrifugal sedimentation is preferred. It is preferable that 99% by volume or more of the cerium oxide particles in the cerium oxide abrasive is 3000 nm or less. Further, since it is used for polishing a semiconductor chip, the content of alkali metals and halogens is preferably suppressed to 10 ppm or less.
本発明において、酸化セリウム粉末を作製する方法として、焼成法またはセリウム化合物水溶液の酸化法が使用できる。焼成温度は、６００℃以上９００℃以下が好ましい。セリウム化合物水溶液中で酸化する方法としては、セリウム水溶液に硝酸等の酸及び過酸化水素水等の酸化剤を加える方法がある。上記の方法により製造された酸化セリウム粒子は凝集しているため、機械的に粉砕することが好ましい。粉砕方法として、ジェットミル等による乾式粉砕や遊星ビーズミル等による湿式粉砕方法が好ましい。ジェットミルは、例えば化学工学業論文集第６巻第５号（１９８０）５２７〜５３２頁に説明されている。 In the present invention, as a method of producing the cerium oxide powder, a firing method or an oxidation method of a cerium compound aqueous solution can be used. The firing temperature is preferably from 600 ° C to 900 ° C. As a method of oxidizing in a cerium compound aqueous solution, there is a method of adding an acid such as nitric acid and an oxidizing agent such as aqueous hydrogen peroxide to the cerium aqueous solution. Since the cerium oxide particles produced by the above method are agglomerated, it is preferable to mechanically pulverize the particles. As the pulverization method, a dry pulverization method using a jet mill or the like or a wet pulverization method using a planetary bead mill or the like is preferable. The jet mill is described, for example, in Chemical Engineering Transactions, Vol. 6, No. 5, (1980), pp. 527-532.
本発明における酸化セリウムスラリーは、例えば上記の特徴を有する酸化セリウム粒子とポリアクリル酸アンモニウム塩を含む分散剤と水からなる組成物を分散させることによって得られる。ここで、酸化セリウム粒子の濃度に制限はないが、懸濁液の取り扱いやすさから０．５以上２０重量％以下の範囲が好ましい。また、分散剤として、半導体チップ研磨に使用することからＮａ、Ｋ等のアルカリ金属および、ハロゲン、イオウを含まないものとしてポリアクリル酸アンモニウム塩が好ましい。また、ポリアクリル酸アンモニウム塩と水溶性有機高分子類（ポリグリセリン脂肪酸エステル等）、水溶性陰イオン性界面活性剤（アルキルエーテルカルボン酸塩）、水溶性非イオン性界面活性剤（ポリエチレングリコールモノステアレート等）、水溶性アミン類（モノエタノールアミン等）から選ばれた少なくとも１種類を含む２種類以上の分散剤を使用してもよい。これらの分散剤添加量は、スラリー中の粒子の分散性および沈降防止、さらに研磨傷と分散剤添加量との関係から、酸化セリウム粒子１００重量部に対して０．０１以上２．０重量部以下の範囲が好ましい。ポリアクリル酸アンモニウム塩の分子量（重量平均分子量）は、１０００〜１００００が好ましく、３０００〜８０００がより好ましい。これらの酸化セリウム粒子を水中に分散させる方法としては、通常の撹拌機による分散処理の他にホモジナイザ−、超音波分散機、ビーズミル、遊星ボールミル、振動ミル等を用いることができる。分散後のスラリー中の大きな凝集粒子を分級により除去する方法としては、沈降分離法、液体サイクロン、フィルターろ過等を用いることができる。 The cerium oxide slurry in the present invention can be obtained, for example, by dispersing a composition comprising water and cerium oxide particles having the above characteristics, a dispersant containing ammonium polyacrylate, and water. Here, the concentration of the cerium oxide particles is not limited, but is preferably in the range of 0.5 to 20% by weight from the viewpoint of easy handling of the suspension. As a dispersant, an alkali metal such as Na and K, and ammonium polyacrylate are preferable because they do not contain halogen or sulfur because they are used for polishing semiconductor chips. In addition, ammonium polyacrylate and water-soluble organic polymers (such as polyglycerin fatty acid ester), water-soluble anionic surfactant (alkyl ether carboxylate), and water-soluble nonionic surfactant (polyethylene glycol monoester) Two or more dispersants including at least one selected from water-soluble amines (monoethanolamine and the like) may be used. These dispersants are added in an amount of 0.01 to 2.0 parts by weight based on 100 parts by weight of the cerium oxide particles in view of the dispersibility of the particles in the slurry and prevention of sedimentation, and the relationship between the polishing scratches and the amount of the dispersant added. The following ranges are preferred. The molecular weight (weight average molecular weight) of the ammonium polyacrylate is preferably from 1,000 to 10,000, more preferably from 3,000 to 8,000. As a method for dispersing these cerium oxide particles in water, a homogenizer, an ultrasonic disperser, a bead mill, a planetary ball mill, a vibration mill, or the like can be used in addition to the dispersion treatment using a normal stirrer. As a method of removing large aggregated particles in the slurry after dispersion by classification, a sedimentation separation method, a liquid cyclone, a filter filtration, or the like can be used.
本発明の酸化セリウム研磨剤は、上記スラリ−をそのまま使用してもよいが、Ｎ，Ｎ−ジエチルエタノ−ルアミン、Ｎ，Ｎ−ジメチルエタノ−ルアミン、アミノエチルエタノ−ルアミン等の添加剤を添加して研磨剤とすることができる。 As the cerium oxide abrasive of the present invention, the above slurry may be used as it is, but additives such as N, N-diethylethanolamine, N, N-dimethylethanolamine and aminoethylethanolamine are added. To make an abrasive.
本発明の酸化セリウム研磨剤が使用される無機絶縁膜の作製方法として、低圧ＣＶＤ法、プラズマＣＶＤ法等が挙げられる。低圧ＣＶＤ法によるＳｉＯ２絶縁膜形成は、Ｓｉ源としてモノシラン：ＳｉＨ４、酸素源として酸素：Ｏ２を用いる。このＳｉＨ４−Ｏ２系酸化反応を４００℃程度以下の低温で行わせることにより得られる。場合によっては、ＣＶＤ後１０００℃またはそれ以下の温度で熱処理される。高温リフローによる表面平坦化を図るために、リン：Ｐをドープするときには、ＳｉＨ４−Ｏ２−ＰＨ３系反応ガスを用いることが好ましい。プラズマＣＶＤ法は、通常の熱平衡下では高温を必要とする化学反応が低温でできる利点を有する。プラズマ発生法には、容量結合型と誘導結合型の２つが挙げられる。反応ガスとしては、Ｓｉ源としてＳｉＨ４、酸素源としてＮ２Ｏを用いたＳｉＨ４−Ｎ２Ｏ系ガスとテトラエトキシシラン（ＴＥＯＳ）をＳｉ源に用いたＴＥＯＳ−Ｏ２系ガス（ＴＥＯＳ−プラズマＣＶＤ法）が挙げられる。基板温度は２５０℃〜４００℃、反応圧力は６７〜４００Ｐａの範囲が好ましい。このように、本発明のＳｉＯ２絶縁膜にはリン、ホウ素等の元素がド−プされていても良い。 Examples of a method for manufacturing an inorganic insulating film using the cerium oxide abrasive of the present invention include a low-pressure CVD method and a plasma CVD method. In the formation of the SiO 2 insulating film by the low-pressure CVD method, monosilane: SiH 4 is used as a Si source, and oxygen: O 2 is used as an oxygen source. It can be obtained by performing this SiH 4 —O 2 -based oxidation reaction at a low temperature of about 400 ° C. or less. In some cases, heat treatment is performed at a temperature of 1000 ° C. or less after CVD. In order to surface planarization by high temperature reflow, phosphorus: when doped with P, it is preferable to use a SiH 4 -O 2 -PH 3 system reaction gas. The plasma CVD method has an advantage that a chemical reaction requiring a high temperature can be performed at a low temperature under normal thermal equilibrium. There are two types of plasma generation methods, a capacitive coupling type and an inductive coupling type. As a reaction gas, a SiH 4 -N 2 O-based gas using SiH 4 as a Si source and N 2 O as an oxygen source and a TEOS-O 2 -based gas (TEOS-) using tetraethoxysilane (TEOS) as a Si source are used. Plasma CVD method). The substrate temperature is preferably from 250 ° C. to 400 ° C., and the reaction pressure is preferably from 67 to 400 Pa. Thus, the elements such as phosphorus and boron may be doped in the SiO 2 insulating film of the present invention.
所定の基板として、半導体基板すなわち回路素子と配線パターンが形成された段階の半導体基板、回路素子が形成された段階の半導体基板等の半導体基板上に、ＳｉＯ２絶縁膜層が形成された基板が使用できる。このような半導体基板上に形成されたＳｉＯ２絶縁膜層を、上記酸化セリウム研磨剤で研磨することによって、ＳｉＯ２絶縁膜層表面の凹凸を解消し、半導体基板全面に渡って平滑な面とする。ここで、研磨する装置としては、半導体基板を保持するホルダーと研磨布（パッド）を貼り付けた（回転数が変更可能なモータ等を取り付けてある）定盤を有する一般的な研磨装置が使用できる。研磨布としては、一般的な不織布、発泡ポリウレタン、多孔質フッ素樹脂等が使用でき、特に制限がない。また、研磨布には、スラリーが溜まる様な溝加工を施すことが好ましい。研磨条件には制限はないが、定盤の回転速度は、半導体が飛び出さない様に１００ｒｐｍ以下の低回転が好ましく、半導体基板にかける圧力は、研磨後に傷が発生しない様に１ｋｇ／ｃｍ２以下が好ましい。研磨している間、研磨布にはスラリーをポンプ等で連続的に供給する。この供給量には制限はないが、研磨布の表面が常にスラリーで覆われていることが好ましい。 As a predetermined substrate, a semiconductor substrate such as a semiconductor substrate in which a circuit element and a wiring pattern are formed, and a semiconductor substrate in which a circuit element is formed, such as a semiconductor substrate, is provided with a SiO 2 insulating film layer formed thereon. Can be used. The SiO 2 insulating film layer formed on such a semiconductor substrate is polished with the above-mentioned cerium oxide abrasive to eliminate irregularities on the surface of the SiO 2 insulating film layer and to provide a smooth surface over the entire surface of the semiconductor substrate. I do. Here, as a polishing apparatus, a general polishing apparatus having a holder holding a semiconductor substrate and a platen on which a polishing cloth (pad) is attached (mounted with a motor or the like capable of changing the number of rotations) is used. it can. As the polishing cloth, general nonwoven fabric, foamed polyurethane, porous fluororesin and the like can be used, and there is no particular limitation. Further, it is preferable that the polishing cloth is subjected to groove processing such that the slurry is accumulated. The polishing conditions are not limited, but the rotation speed of the platen is preferably low rotation of 100 rpm or less so that the semiconductor does not jump out, and the pressure applied to the semiconductor substrate is 1 kg / cm 2 so that scratches are not generated after polishing. The following is preferred. During polishing, the slurry is continuously supplied to the polishing cloth by a pump or the like. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the slurry.
研磨終了後の半導体基板は、流水中で良く洗浄後、スピンドライヤ等を用いて半導体基板上に付着した水滴を払い落としてから乾燥させることが好ましい。このようにして平坦化されたＳｉＯ２絶縁膜層の上に、第２層目のアルミニウム配線を形成し、その配線間および配線上に再度上記方法により、ＳｉＯ２絶縁膜を形成後、上記酸化セリウム研磨剤を用いて研磨することによって、絶縁膜表面の凹凸を解消し、半導体基板全面に渡って平滑な面とする。この工程を所定数繰り返すことにより、所望の層数の半導体を製造する。 After the polishing, the semiconductor substrate is preferably washed well in running water, and then dried using a spin drier or the like to remove water droplets attached to the semiconductor substrate. On this way, the SiO 2 insulating film layer which is flattened, forming an aluminum wiring of the second layer, again by the above method on the inter-wiring and the wiring, after forming the SiO 2 insulating film, the oxide By polishing using a cerium abrasive, unevenness on the surface of the insulating film is eliminated, and a smooth surface is formed over the entire surface of the semiconductor substrate. By repeating this process a predetermined number of times, a desired number of semiconductor layers is manufactured.
本発明の酸化セリウム研磨剤は、半導体基板に形成されたＳｉＯ２絶縁膜だけでなく、所定の配線を有する配線板に形成されたＳｉＯ２絶縁膜、ガラス、窒化ケイ素等の無機絶縁膜、フォトマスク・レンズ・プリズム等の光学ガラス、ＩＴＯ等の無機導電膜、ガラス及び結晶質材料で構成される光集積回路・光スイッチング素子・光導波路、光ファイバ−の端面、シンチレ−タ等の光学用単結晶、固体レ−ザ単結晶、青色レ−ザＬＥＤ用サファイア基板、ＳｉＣ、ＧａＰ、ＧａＡｓ等の半導体単結晶、磁気ディスク用ガラス基板、磁気ヘッド等を研磨するために使用される。このように本発明において所定の基板とは、ＳｉＯ２絶縁膜が形成された半導体基板、ＳｉＯ２絶縁膜が形成された配線板、ガラス、窒化ケイ素等の無機絶縁膜が形成された基板、フォトマスク・レンズ・プリズム等の光学ガラス、ＩＴＯ等の無機導電膜、ガラス及び結晶質材料で構成される光集積回路・光スイッチング素子・光導波路、光ファイバ−の端面、シンチレ−タ等の光学用単結晶、固体レ−ザ単結晶、青色レ−ザＬＥＤ用サファイア基板、ＳｉＣ、ＧａＰ、ＧａＡｓ等の半導体単結晶、磁気ディスク用ガラス基板、磁気ヘッド等を含む。 The cerium oxide abrasive of the present invention can be used not only for an SiO 2 insulating film formed on a semiconductor substrate, but also for an SiO 2 insulating film formed on a wiring board having predetermined wiring, an inorganic insulating film such as glass and silicon nitride, Optical glass such as masks, lenses, prisms, etc., inorganic conductive films such as ITO, optical integrated circuits, optical switching elements, optical waveguides made of glass and crystalline materials, optical fiber end faces, scintillators, etc. It is used for polishing single crystals, solid laser single crystals, sapphire substrates for blue laser LEDs, semiconductor single crystals such as SiC, GaP, GaAs, glass substrates for magnetic disks, magnetic heads and the like. Thus the predetermined substrate in the present invention, SiO 2 semiconductor substrate on which an insulating film is formed, SiO 2 insulating film is formed wiring board, a glass substrate an inorganic insulating film such as silicon nitride is formed, the photo Optical glass such as masks, lenses, prisms, etc., inorganic conductive films such as ITO, optical integrated circuits, optical switching elements, optical waveguides made of glass and crystalline materials, optical fiber end faces, scintillators, etc. Includes single crystals, solid laser single crystals, sapphire substrates for blue laser LEDs, semiconductor single crystals of SiC, GaP, GaAs, etc., glass substrates for magnetic disks, magnetic heads, and the like.
実施例１
（酸化セリウム粒子の作製１）
炭酸セリウム水和物２ｋｇを白金製容器に入れ、８００℃で２時間空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末をＸ線回折法で相同定を行ったところ、酸化セリウムであることを確認した。焼成粉末粒子径は３０〜１００μｍであった。焼成粉末粒子表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム一次粒子径を測定したところ、その分布の中央値が１９０ｎｍ、最大値が５００ｎｍであった。焼成粉末についてＸ線回折精密測定を行い、その結果についてリートベルト法（ＲＩＥＴＡＮ−９４）による解析で、一次粒子径を表わす構造パラメーター：Ｘの値が０．０８０、等方的微少歪みを表わす構造パラメーター：Ｙの値が０．２２３であった。酸化セリウム粉末１ｋｇをジェットミルを用いて乾式粉砕を行った。粉砕粒子について走査型電子顕微鏡で観察したところ、一次粒子径と同等サイズの小さな粒子の他に、１μｍから３μｍの大きな粉砕粒子と０．５から１μｍの粉砕粒子が混在していた。これらの粉砕粒子は、一次粒子の凝集体ではない。粉砕粒子についてＸ線回折精密測定を行い、その結果についてリートベルト法（ＲＩＥＴＡＮ−９４）による解析で、一次粒子径を表わす構造パラメーター：Ｘの値が０．０８５、等方的微少歪みを表わす構造パラメーター：Ｙの値が０．２６４であった。この結果、粉砕による一次粒子径変量は殆どなく、また粉砕により粒子に歪みが導入されていた。さらに、ＢＥＴ法による比表面積測定の結果、１０ｍ２／ｇであることがわかった。
Example 1
(Preparation of cerium oxide particles 1)
2 kg of cerium carbonate hydrate was placed in a platinum container and calcined at 800 ° C. for 2 hours in air to obtain about 1 kg of a yellow-white powder. When this powder was subjected to phase identification by X-ray diffraction, it was confirmed that the powder was cerium oxide. The particle diameter of the calcined powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, grain boundaries of cerium oxide were observed. When the primary particle diameter of cerium oxide surrounded by the grain boundaries was measured, the median of the distribution was 190 nm and the maximum was 500 nm. X-ray diffraction precision measurement is performed on the calcined powder, and the result is analyzed by the Rietveld method (Rietan-94). As a result, a structure parameter representing the primary particle diameter: a value of X of 0.080, a structure showing isotropic micro-strain Parameter: The value of Y was 0.223. 1 kg of cerium oxide powder was dry-ground using a jet mill. When the pulverized particles were observed with a scanning electron microscope, large pulverized particles of 1 μm to 3 μm and pulverized particles of 0.5 to 1 μm were mixed together with small particles having a size equivalent to the primary particle diameter. These ground particles are not aggregates of primary particles. X-ray diffraction precision measurement is performed on the pulverized particles, and the result is analyzed by the Rietveld method (Rietan-94). The structure parameter representing the primary particle diameter: the value of X is 0.085, and the structure represents isotropic micro-strain. Parameter: The value of Y was 0.264. As a result, there was almost no variation in the primary particle diameter due to the pulverization, and distortion was introduced into the particles by the pulverization. Further, the specific surface area measured by the BET method was found to be 10 m 2 / g.
（酸化セリウム粒子の作製２）
酸化セリウム粒子の作製１で用いたのと同じ炭酸セリウム水和物２ｋｇを白金製容器に入れ、７５０℃で２時間空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末をＸ線回折法で相同定を行ったところ、酸化セリウムであることを確認した。焼成粉末粒子径は３０〜１００μｍであった。焼成粉末粒子表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム一次粒子径を測定したところ、その分布の中央値が１４１ｎｍ、最大値が４００ｎｍであった。焼成粉末についてＸ線回折精密測定を行い、その結果についてリートベルト法（ＲＩＲＴＡＮ−９４）による解析で、一次粒子径を表わす構造パラメーター：Ｘの値が０．１０１、等方的微少歪みを表わす構造パラメーター：Ｙの値が０．２２３であった。酸化セリウム粉末１ｋｇをジェットミルを用いて乾式粉砕を行った。粉砕粒子について走査型電子顕微鏡で観察したところ、一次粒子径と同等サイズの小さな粒子の他に、１μｍから３μｍの大きな粉砕粒子と０．５から１μｍの粉砕粒子が混在していた。これらの粉砕粒子は、一次粒子の凝集体ではない。粉砕粒子についてＸ線回折精密測定を行い、その結果についてリートベルト法（ＲＩＥＴＡＮ−９４）による解析で、一次粒子径を表わす構造パラメーター：Ｘの値が０．１０４、等方的微少歪みを表わす構造パラメーター：Ｙの値が０．３１５であった。この結果、粉砕による一次粒子径変量は殆どなく、また粉砕により粒子に歪みが導入されていた。さらに、ＢＥＴ法による比表面積測定の結果、１６ｍ２／ｇであることがわかった。
(Preparation of cerium oxide particles 2)
2 kg of the same cerium carbonate hydrate used in Preparation 1 of the cerium oxide particles was placed in a platinum container and calcined at 750 ° C. for 2 hours in the air to obtain about 1 kg of a yellow-white powder. When this powder was subjected to phase identification by X-ray diffraction, it was confirmed that the powder was cerium oxide. The particle diameter of the calcined powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, grain boundaries of cerium oxide were observed. When the primary particle size of cerium oxide surrounded by the grain boundaries was measured, the median value of the distribution was 141 nm and the maximum value was 400 nm. X-ray diffraction precision measurement is performed on the calcined powder, and the result is analyzed by the Rietveld method (RIRTAN-94). As a result, a structure parameter representing the primary particle diameter: a value of X of 0.101, a structure showing isotropic micro-strain Parameter: The value of Y was 0.223. 1 kg of cerium oxide powder was dry-ground using a jet mill. When the pulverized particles were observed with a scanning electron microscope, large pulverized particles of 1 μm to 3 μm and pulverized particles of 0.5 to 1 μm were mixed together with small particles having a size equivalent to the primary particle diameter. These ground particles are not aggregates of primary particles. X-ray diffraction precision measurement is performed on the pulverized particles, and the result is analyzed by the Rietveld method (Rietan-94). The structure parameter representing the primary particle diameter: the value of X is 0.104, and the structure represents isotropic micro-strain. Parameter: The value of Y was 0.315. As a result, there was almost no variation in the primary particle diameter due to the pulverization, and distortion was introduced into the particles by the pulverization. Furthermore, the specific surface area measured by the BET method was found to be 16 m 2 / g.
（酸化セリウムスラリーの作製）
上記作製１、２の酸化セリウム粒子１ｋｇとポリアクリル酸アンモニウム塩水溶液（４０重量％）２３ｇと脱イオン水８９７７ｇを混合し、撹拌しながら超音波分散を１０分間施した。得られたスラリーを５μｍフィルターでろ過をし、さらに脱イオン水を加えることにより３ｗｔ％研磨剤を得た。スラリーｐＨは８．３であった。スラリー粒子の粒度分布をレーザー回折法（測定装置：Ｍａｌｖｅｒｎ Ｉｎｓｔｒｕｍｅｎｔｓ社製 Ｍａｓｔｅｒｓｉｚｅｒ Ｍｉｃｒｏｐｌｕｓ、光源Ｈｅ−Ｎｅレーザー、粒子の屈折率１．９２８５、吸収０で測定）を用いて調べたところ、中央値が酸化セリウム粒子の作製１によるスラリーは２００ｎｍ、酸化セリウム粒子の作製２によるスラリーは２８０ｎｍであった。５００ｎｍ以上の粒子の含有量は、酸化セリウム粒子の作製１によるスラリーが１３．４体積％、酸化セリウム粒子の作製２によるスラリーが３７．８体積％、最大粒子径は共に１９５０ｎｍであった。スラリーの分散性およびスラリー粒子の電荷を調べるため、スラリーのゼータ電位を調べた。両側に白金製電極を取り付けてある測定セルに酸化セリウムスラリーを入れ、両電極に１０Ｖの電圧を印加した。電圧を印加することにより電荷を持ったスラリー粒子は、その電荷と反対の極を持つ電極側に移動する。この移動速度を求めることにより、粒子のゼータ電位を求めることができる。ゼータ電位測定の結果、それぞれマイナスに荷電し、−３８ｍＶ、−５５ｍＶと絶対値が大きく分散性が良好であることを確認した。
(Preparation of cerium oxide slurry)
1 kg of the cerium oxide particles prepared in Preparations 1 and 2, 23 g of an aqueous solution of ammonium polyacrylate (40% by weight), and 8977 g of deionized water were mixed and subjected to ultrasonic dispersion for 10 minutes while stirring. The obtained slurry was filtered with a 5 μm filter, and 3 wt% abrasive was obtained by adding deionized water. The slurry pH was 8.3. When the particle size distribution of the slurry particles was measured using a laser diffraction method (measurement device: Mastersizer Microplus manufactured by Malvern Instruments, light source He-Ne laser, refractive index of the particles 1.9285, measured with zero absorption), the median value was oxidized. The slurry from the preparation 1 of the cerium particles was 200 nm, and the slurry from the preparation 2 from the cerium oxide particles was 280 nm. The content of the particles having a particle diameter of 500 nm or more was 13.4% by volume for the slurry obtained from the preparation 1 of the cerium oxide particles, 37.8% by volume for the slurry obtained from the preparation 2 of the cerium oxide particles, and the maximum particle diameter was 1950 nm. In order to examine the dispersibility of the slurry and the charge of the slurry particles, the zeta potential of the slurry was examined. The cerium oxide slurry was placed in a measurement cell having platinum electrodes attached to both sides, and a voltage of 10 V was applied to both electrodes. When a voltage is applied, the charged slurry particles move to the electrode side having the opposite polarity to the charge. By determining the moving speed, the zeta potential of the particles can be determined. As a result of the measurement of zeta potential, it was confirmed that each was negatively charged, and the absolute values were large at −38 mV and −55 mV, and the dispersibility was good.
（絶縁膜層の研磨）
保持する基板取り付け用の吸着パッドを貼り付けたホルダーに、ＴＥＯＳ−プラズマＣＶＤ法で作製したＳｉＯ２絶縁膜を形成させたＳｉウエハをセットし、多孔質ウレタン樹脂製の研磨パッドを貼り付けた定盤上に、絶縁膜面を下にしてホルダーを載せ、さらに加工荷重が３００ｇ／ｃｍ２になるように重しを載せた。定盤上に、上記の酸化セリウムスラリー（固形分：３重量％）を５０ｃｃ／ｍｉｎの速度で滴下しながら、定盤を３０ｒｐｍで２分間回転させ、絶縁膜を研磨した。研磨後ウエハをホルダーから取り外して、流水で良く洗浄後、超音波洗浄機によりさらに２０分間洗浄した。洗浄後、ウエハをスピンドライヤーで水滴を除去し、１２０℃の乾燥機で１０分間乾燥させた。光干渉式膜厚測定装置を用いて、研磨前後の膜厚変化を測定した結果、この研磨によりそれぞれ６２０ｎｍ、６４０ｎｍ（研磨速度：３１０ｎｍ／ｍｉｎ、３２０ｎｍ／ｍｉｎ）の絶縁膜が削られ、ウエハ全面に渡って均一の厚みになっていることがわかった。また、光学顕微鏡を用いて絶縁膜表面を観察したところ、明確な傷は見られなかった。
(Polishing of insulating film layer)
A Si wafer on which a SiO 2 insulating film formed by a TEOS-plasma CVD method was formed was set on a holder to which a suction pad for attaching a substrate to be held was attached, and a polishing pad made of porous urethane resin was attached. The holder was placed on the board with the insulating film side down, and a weight was placed so that the processing load was 300 g / cm 2 . While the cerium oxide slurry (solid content: 3% by weight) was dropped on the platen at a rate of 50 cc / min, the platen was rotated at 30 rpm for 2 minutes to polish the insulating film. After polishing, the wafer was removed from the holder, washed well with running water, and further washed with an ultrasonic cleaner for 20 minutes. After the washing, water droplets were removed from the wafer with a spin drier, and the wafer was dried with a dryer at 120 ° C. for 10 minutes. As a result of measuring the change in film thickness before and after polishing using an optical interference type film thickness measuring device, the insulating films of 620 nm and 640 nm (polishing speed: 310 nm / min, 320 nm / min) were respectively removed by this polishing, and the entire surface of the wafer was removed. It was found that the thickness became uniform over the entire range. When the surface of the insulating film was observed using an optical microscope, no clear scratch was found.
実施例２
（酸化セリウム粒子の作製）
炭酸セリウム水和物２ｋｇを白金製容器に入れ、８００℃で２時間空気中で焼成することにより、黄白色の粉末を約１ｋｇ得た。この粉末をＸ線回折法で相同定を行ったところ、酸化セリウムであることを確認した。焼成粉末粒子径は３０〜１００μｍであった。焼成粉末粒子表面を走査型電子顕微鏡で観察したところ、酸化セリウムの粒界が観察された。粒界に囲まれた酸化セリウム一次粒子径を測定したところ、その分布の中央値が１９０ｎｍ、最大値が５００ｎｍであった。焼成粉末についてＸ線回折精密測定を行い、その結果についてリートベルト法（ＲＩＥＴＡＮ−９４）による解析で、一次粒子径を表わす構造パラメーター：Ｘの値が０．０８０、等方的微少歪みを表わす構造パラメーター：Ｙの値が０．２２３であった。酸化セリウム粉末１ｋｇをジェットミルを用いて乾式粉砕を行った。粉砕粒子について走査型電子顕微鏡で観察したところ、一次粒子径と同等サイズの小さな粒子の他に、１μｍから３μｍの大きな粉砕粒子と０．５から１μｍの粉砕粒子が混在していた。これらの粉砕粒子は、一次粒子の凝集体ではない。粉砕粒子についてＸ線回折精密測定を行い、その結果についてリートベルト法（ＲＩＥＴＡＮ−９４）による解析で、一次粒子径を表わす構造パラメーター：Ｘの値が０．０８５、等方的微少歪みを表わす構造パラメーター：Ｙの値が０．２６４であった。この結果、粉砕による一次粒子径変量は殆どなく、また粉砕により粒子に歪みが導入されていた。さらに、ＢＥＴ法による比表面積測定の結果、１０ｍ２／ｇであることがわかった。
Example 2
(Preparation of cerium oxide particles)
2 kg of cerium carbonate hydrate was placed in a platinum container and calcined at 800 ° C. for 2 hours in air to obtain about 1 kg of a yellow-white powder. When this powder was subjected to phase identification by X-ray diffraction, it was confirmed that the powder was cerium oxide. The particle diameter of the calcined powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, grain boundaries of cerium oxide were observed. When the primary particle diameter of cerium oxide surrounded by the grain boundaries was measured, the median of the distribution was 190 nm and the maximum was 500 nm. X-ray diffraction precision measurement is performed on the calcined powder, and the result is analyzed by the Rietveld method (Rietan-94). As a result, a structure parameter representing the primary particle diameter: a value of X of 0.080, a structure showing isotropic micro-strain Parameter: The value of Y was 0.223. 1 kg of cerium oxide powder was dry-ground using a jet mill. When the pulverized particles were observed with a scanning electron microscope, large pulverized particles of 1 μm to 3 μm and pulverized particles of 0.5 to 1 μm were mixed together with small particles having a size equivalent to the primary particle diameter. These ground particles are not aggregates of primary particles. X-ray diffraction precision measurement is performed on the pulverized particles, and the result is analyzed by the Rietveld method (Rietan-94). The structure parameter representing the primary particle diameter: the value of X is 0.085, and the structure represents isotropic micro-strain. Parameter: The value of Y was 0.264. As a result, there was almost no variation in the primary particle diameter due to the pulverization, and distortion was introduced into the particles by the pulverization. Further, the specific surface area measured by the BET method was found to be 10 m 2 / g.
（酸化セリウムスラリーの作製）
上記の酸化セリウム粒子１ｋｇとポリアクリル酸アンモニウム塩水溶液（４０重量％）２３ｇと脱イオン水８９７７ｇを混合し、撹拌しながら超音波分散を１０分間施した。得られたスラリーを１μｍフィルターでろ過をし、さらに脱イオン水を加えることにより３ｗｔ％研磨剤を得た。スラリーｐＨは８．３であった。スラリー粒子の粒度分布をレーザー回折法を用いて調べたところ、中央値が２００ｎｍ、５００ｎｍ以上の含有量は５．１体積％、最大粒子径は７８０ｎｍであった。スラリーの分散性およびスラリー粒子の電荷を調べるため、スラリーのゼータ電位を調べた。両側に白金製電極を取り付けてある測定セルに酸化セリウムスラリーを入れ、両電極に１０Ｖの電圧を印加した。電圧を印加することにより電荷を持ったスラリー粒子は、その電荷と反対の極を持つ電極側に移動する。この移動速度を求めることにより、粒子のゼータ電位を求めることができる。ゼータ電位測定の結果、マイナスに荷電し、−５０ｍＶと絶対値が大きく分散性が良好であることを確認した。
(Preparation of cerium oxide slurry)
1 kg of the above-mentioned cerium oxide particles, 23 g of an aqueous solution of ammonium polyacrylate (40% by weight) and 8977 g of deionized water were mixed and subjected to ultrasonic dispersion for 10 minutes while stirring. The obtained slurry was filtered through a 1 μm filter, and 3 wt% abrasive was obtained by adding deionized water. The slurry pH was 8.3. When the particle size distribution of the slurry particles was examined using a laser diffraction method, the median value was 200 nm, the content of 500 nm or more was 5.1% by volume, and the maximum particle size was 780 nm. In order to examine the dispersibility of the slurry and the charge of the slurry particles, the zeta potential of the slurry was examined. The cerium oxide slurry was placed in a measurement cell having platinum electrodes attached to both sides, and a voltage of 10 V was applied to both electrodes. When a voltage is applied, the charged slurry particles move to the electrode side having the opposite polarity to the charge. By determining the moving speed, the zeta potential of the particles can be determined. As a result of zeta potential measurement, it was confirmed that the sample was negatively charged, had a large absolute value of −50 mV, and had good dispersibility.
（絶縁膜層の研磨）
保持する基板取り付け用の吸着パッドを貼り付けたホルダーに、ＴＥＯＳ−プラズマＣＶＤ法で作製したＳｉＯ２絶縁膜を形成させたＳｉウエハをセットし、多孔質ウレタン樹脂製の研磨パッドを貼り付けた定盤上に、絶縁膜面を下にしてホルダーを載せ、さらに加工荷重が３００ｇ／ｃｍ２になるように重しを載せた。定盤上に、上記の酸化セリウムスラリー（固形分：３重量％）を５０ｃｃ／ｍｉｎの速度で滴下しながら、定盤を３０ｒｐｍで２分間回転させ、絶縁膜を研磨した。研磨後ウエハをホルダーから取り外して、流水で良く洗浄後、超音波洗浄機によりさらに２０分間洗浄した。洗浄後、ウエハをスピンドライヤーで水滴を除去し、１２０℃の乾燥機で１０分間乾燥させた。光干渉式膜厚測定装置を用いて、研磨前後の膜厚変化を測定した結果、この研磨により６００ｎｍ（研磨速度：３００ｎｍ／ｍｉｎ）の絶縁膜が削られ、ウエハ全面に渡って均一の厚みになっていることがわかった。また、光学顕微鏡を用いて絶縁膜表面を観察したところ、明確な傷は見られなかった。
(Polishing of insulating film layer)
A Si wafer on which a SiO 2 insulating film formed by a TEOS-plasma CVD method was formed was set on a holder to which a suction pad for attaching a substrate to be held was attached, and a polishing pad made of porous urethane resin was attached. The holder was placed on the board with the insulating film side down, and a weight was placed so that the processing load was 300 g / cm 2 . While the cerium oxide slurry (solid content: 3% by weight) was dropped on the platen at a rate of 50 cc / min, the platen was rotated at 30 rpm for 2 minutes to polish the insulating film. After polishing, the wafer was removed from the holder, washed well with running water, and further washed with an ultrasonic cleaner for 20 minutes. After the washing, water droplets were removed from the wafer with a spin drier, and the wafer was dried with a dryer at 120 ° C. for 10 minutes. As a result of measuring the change in film thickness before and after polishing using an optical interference type film thickness measuring device, this polishing removes an insulating film of 600 nm (polishing rate: 300 nm / min), and has a uniform thickness over the entire surface of the wafer. It turned out that it was. When the surface of the insulating film was observed using an optical microscope, no clear scratch was found.
比較例１
実施例２で用いたのと同じ酸化セリウム粒子１ｋｇとポリアクリル酸アンモニウム塩水溶液（４０重量％）２３ｇと脱イオン水８９７７ｇを混合し、撹拌しながら超音波分散を１０分間施し、さらに脱イオン水を加えることにより３ｗｔ％研磨剤を得た。スラリーｐＨは８．２であった。スラリー粒子の粒度分布をレーザー回折法を用いて調べたところ、中央値は６００ｎｍ、５００ｎｍ以上の含有量は５６体積％、最大粒子径は３３００ｎｍであった。スラリーの分散性およびスラリー粒子の電荷を調べるため、スラリーのゼータ電位を調べた。両側に白金製電極を取り付けてある測定セルに酸化セリウムスラリーを入れ、両電極に１０Ｖの電圧を印加した。電圧を印加することにより電荷を持ったスラリー粒子は、その電荷と反対の極を持つ電極側に移動する。この移動速度を求めることにより、粒子のゼータ電位を求めることができる。ゼータ電位測定の結果、マイナスに荷電し、−３５ｍＶと絶対値が大きく分散性が良好であることを確認した。
Comparative Example 1
1 kg of the same cerium oxide particles as used in Example 2, 23 g of an aqueous solution of ammonium polyacrylate (40% by weight) and 8977 g of deionized water were mixed, subjected to ultrasonic dispersion with stirring for 10 minutes, and further deionized water. Was added to obtain a 3 wt% abrasive. The slurry pH was 8.2. When the particle size distribution of the slurry particles was examined using a laser diffraction method, the median value was 600 nm, the content of 500 nm or more was 56% by volume, and the maximum particle size was 3300 nm. In order to examine the dispersibility of the slurry and the charge of the slurry particles, the zeta potential of the slurry was examined. The cerium oxide slurry was placed in a measurement cell having platinum electrodes attached to both sides, and a voltage of 10 V was applied to both electrodes. When a voltage is applied, the charged slurry particles move to the electrode side having the opposite polarity to the charge. By determining the moving speed, the zeta potential of the particles can be determined. As a result of zeta potential measurement, it was confirmed that the sample was negatively charged, had a large absolute value of −35 mV, and had good dispersibility.
（絶縁膜層の研磨）
保持する基板取り付け用の吸着パッドを貼り付けたホルダーに、ＴＥＯＳ−プラズマＣＶＤ法で作製したＳｉＯ２絶縁膜を形成させたＳｉウエハをセットし、多孔質ウレタン樹脂製の研磨パッドを貼り付けた定盤上に、絶縁膜面を下にしてホルダーを載せ、さらに加工荷重が３００ｇ／ｃｍ２になるように重しを載せた。定盤上に、上記の酸化セリウムスラリー（固形分：３重量％）を５０ｃｃ／ｍｉｎの速度で滴下しながら、定盤を３０ｒｐｍで２分間回転させ、絶縁膜を研磨した。研磨後ウエハをホルダーから取り外して、流水で良く洗浄後、超音波洗浄機によりさらに２０分間洗浄した。洗浄後、ウエハをスピンドライヤーで水滴を除去し、１２０℃の乾燥機で１０分間乾燥させた。光干渉式膜厚測定装置を用いて、研磨前後の膜厚変化を測定した結果、この研磨により７８０ｎｍ（研磨速度：３４０ｎｍ／ｍｉｎ）の絶縁膜が削られ、ウエハ全面に渡って均一の厚みになっていることがわかった。光学顕微鏡を用いて絶縁膜表面を観察したところ、幅の狭い傷がウエハ前面にわたって無数に見られた。
(Polishing of insulating film layer)
A Si wafer on which a SiO 2 insulating film formed by a TEOS-plasma CVD method was formed was set on a holder to which a suction pad for attaching a substrate to be held was attached, and a polishing pad made of porous urethane resin was attached. The holder was placed on the board with the insulating film side down, and a weight was placed so that the processing load was 300 g / cm 2 . While the cerium oxide slurry (solid content: 3% by weight) was dropped on the platen at a rate of 50 cc / min, the platen was rotated at 30 rpm for 2 minutes to polish the insulating film. After polishing, the wafer was removed from the holder, washed well with running water, and further washed with an ultrasonic cleaner for 20 minutes. After the washing, water droplets were removed from the wafer with a spin drier, and the wafer was dried with a dryer at 120 ° C. for 10 minutes. As a result of measuring a change in film thickness before and after polishing using an optical interference type film thickness measuring device, an insulating film having a thickness of 780 nm (polishing speed: 340 nm / min) was removed by the polishing, and a uniform thickness was obtained over the entire surface of the wafer. It turned out that it was. When the surface of the insulating film was observed using an optical microscope, countless narrow scratches were found over the front surface of the wafer.
比較例２
実施例と同様にＴＥＯＳ−ＣＶＤ法で作製したＳｉＯ２絶縁膜を形成させたＳｉウエハについて、市販シリカスラリー（キャボット社製、商品名ＳＳ２２５）を用いて研磨を行った。この市販スラリーのｐＨは１０．３で、ＳｉＯ２粒子を１２．５ｗｔ％含んでいるものである。研磨条件は実施例と同一である。その結果、研磨による傷は見られず、また均一に研磨がなされたが、２分間の研磨により１５０ｎｍ（研磨速度：７５ｎｍ／ｍｉｎ）の絶縁膜層しか削れなかった。
Comparative Example 2
The Si wafer on which the SiO 2 insulating film was formed by the TEOS-CVD method in the same manner as in the example was polished using a commercially available silica slurry (trade name: SS225, manufactured by Cabot Corporation). This commercial slurry had a pH of 10.3 and contained 12.5 wt% of SiO 2 particles. The polishing conditions are the same as in the embodiment. As a result, no scratches were found due to the polishing, and the polishing was performed uniformly, but only 150 nm (polishing rate: 75 nm / min) of the insulating film layer could be removed by polishing for 2 minutes.
Claims (4)
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009028814A (en) * | 2007-07-25 | 2009-02-12 | Sumitomo Metal Mining Co Ltd | Sapphire substrate polishing method |
| US8062547B2 (en) | 2005-06-03 | 2011-11-22 | K.C. Tech Co., Ltd. | CMP slurry, preparation method thereof and method of polishing substrate using the same |
| CN1818002B (en) * | 2004-12-16 | 2013-04-10 | K.C.科技股份有限公司 | Abrasive particles, polishing slurry, and producing method thereof |
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2004
- 2004-05-10 JP JP2004140115A patent/JP2004289170A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1818002B (en) * | 2004-12-16 | 2013-04-10 | K.C.科技股份有限公司 | Abrasive particles, polishing slurry, and producing method thereof |
| US8062547B2 (en) | 2005-06-03 | 2011-11-22 | K.C. Tech Co., Ltd. | CMP slurry, preparation method thereof and method of polishing substrate using the same |
| JP2009028814A (en) * | 2007-07-25 | 2009-02-12 | Sumitomo Metal Mining Co Ltd | Sapphire substrate polishing method |
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