JP2023141786A - Polishing slurry and polishing method - Google Patents
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- 238000005498 polishing Methods 0.000 title claims abstract description 109
- 239000002002 slurry Substances 0.000 title claims abstract description 42
- 238000000034 method Methods 0.000 title claims description 9
- 239000002245 particle Substances 0.000 claims abstract description 53
- 239000011164 primary particle Substances 0.000 claims abstract description 38
- 239000011163 secondary particle Substances 0.000 claims abstract description 24
- 239000011230 binding agent Substances 0.000 claims abstract description 23
- 239000007788 liquid Substances 0.000 claims abstract description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 20
- 239000012530 fluid Substances 0.000 claims description 12
- 238000003754 machining Methods 0.000 claims description 12
- 239000000377 silicon dioxide Substances 0.000 claims description 10
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 8
- 235000012239 silicon dioxide Nutrition 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 239000013078 crystal Substances 0.000 claims description 5
- 230000003746 surface roughness Effects 0.000 abstract description 21
- 239000000463 material Substances 0.000 abstract description 4
- 235000012431 wafers Nutrition 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 10
- 238000012360 testing method Methods 0.000 description 7
- 239000000654 additive Substances 0.000 description 4
- 239000002612 dispersion medium Substances 0.000 description 4
- 229910010271 silicon carbide Inorganic materials 0.000 description 4
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- 239000004640 Melamine resin Substances 0.000 description 1
- 229930182556 Polyacetal Natural products 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 239000012320 chlorinating reagent Substances 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000113 methacrylic resin Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
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Abstract
Description
本発明は研磨スラリー及び研磨方法に関する。 The present invention relates to a polishing slurry and a polishing method.
例えば、被研磨物としてのＳｉウェハをラップ加工する場合、Ｓｉウェハと研磨パッドとの間に研磨スラリーを介在させ、所定の面圧の下でＳｉウェハと研磨体とを相対移動させることにより、Ｓｉウェハを研磨する（特許文献１）。この研磨スラリーの一例が特許文献２に開示されている。この研磨スラリーは、加工液と、加工液に分散された無数の研磨粒子とを有している。 For example, when lapping a Si wafer as an object to be polished, a polishing slurry is interposed between the Si wafer and a polishing pad, and the Si wafer and polishing body are moved relative to each other under a predetermined surface pressure. A Si wafer is polished (Patent Document 1). An example of this polishing slurry is disclosed in Patent Document 2. This polishing slurry includes a machining liquid and countless abrasive particles dispersed in the machining liquid.
一般的な研磨スラリーでは、各研磨粒子は、シリカ、アルミナ等の粒状をなす一次粒子である。Ｓｉウェハをラップ加工で研磨する場合には、Ｓｉウェハのモース硬度が７であることから、各研磨粒子として、モース硬度が９のアルミナ又はシリコンカーバイドが用いられることが一般的である。加工液は、水等の分散媒と、添加剤とからなる。研磨スラリーが化学的機械研磨（Chemical Mechanical Polishing（ＣＭＰ））方法に用いられる場合には、添加剤として、硝酸第二鉄や過酸化水素水等の酸化剤等も用いられる。 In a typical polishing slurry, each polishing particle is a granular primary particle of silica, alumina, or the like. When polishing a Si wafer by lapping, since the Mohs hardness of the Si wafer is 7, alumina or silicon carbide, which has a Mohs hardness of 9, is generally used as each polishing particle. The processing liquid consists of a dispersion medium such as water and additives. When the polishing slurry is used in a chemical mechanical polishing (CMP) method, oxidizing agents such as ferric nitrate and hydrogen peroxide are also used as additives.
しかし、従来の研磨スラリーでは、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとの両立が困難である。すなわち、高い研磨レートを求めて粒径の大きな研磨粒子を採用すれば、研磨後の被研磨物の表面粗さが大きくなってしまう。また、この場合、研磨後の被研磨物にスクラッチや加工変質層等のダメージも生じ易い。一方、研磨後の被研磨物の表面粗さを小さくするために粒径の小さな研磨粒子を採用すれば、研磨レートが低すぎ、加工に長時間を要してしまう。 However, with conventional polishing slurries, it is difficult to achieve both a high polishing rate and a small surface roughness of the polished object after polishing. That is, if abrasive particles with a large particle size are employed in order to obtain a high polishing rate, the surface roughness of the polished object will increase after polishing. Furthermore, in this case, damage such as scratches and damaged layers is likely to occur on the polished object after polishing. On the other hand, if abrasive particles with a small particle size are used to reduce the surface roughness of the object to be polished after polishing, the polishing rate will be too low and processing will take a long time.
本発明は、上記従来の実情に鑑みてなされたものであって、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとの両立を行い易い研磨スラリーを提供することを解決すべき課題としている。また、本発明は、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとの両立を行い易い研磨方法を提供することを解決すべき課題としている。 The present invention has been made in view of the above-mentioned conventional situation, and the problem to be solved is to provide a polishing slurry that can easily achieve both a high polishing rate and a small surface roughness of the polished object after polishing. It is said that Another object of the present invention is to provide a polishing method that can easily achieve both a high polishing rate and a small surface roughness of the object to be polished after polishing.
発明者らは、従来の研磨スラリーにおいて、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとの両立が困難である理由について鋭意検討した。発明者らは、まず、研磨スラリーによる被研磨物の研磨メカニズムについて検討した。被研磨物の研磨は、被研磨物と各研磨粒子との相対移動中、被研磨物から個々の研磨粒子に反力が作用し、各研磨粒子が各反力に対抗することによって進行すると考えられる。粒径の大きな研磨粒子は、反力に強く対抗し、つまり被研磨物に対して攻撃性が高く、高い研磨レートを実現できる。他方、粒径の大きな研磨粒子を用いると、研磨後の被研磨物の表面粗さが大きくなり易いとともに、被研磨物がスクラッチ等を生じ易い。一方、粒径の小さな研磨粒子は、反力に対抗し難く、つまり被研磨物に対して攻撃性が低く、低い研磨レートしか実現できない。他方、粒径の小さな研磨粒子を用いると、研磨後の被研磨物の表面粗さを小さくすることができる。 The inventors have conducted extensive studies on the reason why it is difficult to achieve both a high polishing rate and a small surface roughness of the polished object in conventional polishing slurries. The inventors first studied the mechanism of polishing an object to be polished using a polishing slurry. It is believed that polishing of the object to be polished progresses by a reaction force acting on each abrasive particle from the object to be polished during relative movement between the object to be polished and each abrasive particle, and each abrasive particle resisting each reaction force. It will be done. Abrasive particles with a large particle size strongly resist reaction force, that is, are highly aggressive toward the object to be polished, and can achieve a high polishing rate. On the other hand, when abrasive particles with a large particle size are used, the surface roughness of the polished object tends to increase after polishing, and the polished object tends to be prone to scratches and the like. On the other hand, abrasive particles with a small particle size have difficulty resisting reaction force, that is, have low aggressiveness toward the object to be polished, and can only achieve a low polishing rate. On the other hand, if abrasive particles with a small particle size are used, the surface roughness of the polished object can be reduced.
従来の研磨スラリーにおいて、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとの両立が困難である理由は、各研磨粒子が粒状をなす一次粒子であり、個々の割れ難い研磨粒子が表面によって被研磨物を研磨することにあると考えた。そこで、各研磨粒子が二次粒子を有することを指向した。二次粒子は、無数の一次粒子と、各一次粒子を結合する結合材とからなる。特に、一次粒子が平板状をなしていることが好ましいと考えた。こうして得た研磨スラリーを用いて被研磨物を研磨する試験を行ったところ、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとの両立が得られることが実証された。これらの知見に基づき、本発明は完成された。 The reason why it is difficult for conventional polishing slurries to achieve both a high polishing rate and a small surface roughness of the polished object after polishing is that each abrasive particle is a granular primary particle, and each hard-to-break abrasive particle is The idea was to polish the object by its surface. Therefore, we aimed for each abrasive particle to have secondary particles. The secondary particles consist of countless primary particles and a binder that binds each primary particle. In particular, it was considered preferable that the primary particles have a tabular shape. A test was conducted to polish an object using the polishing slurry obtained in this way, and it was demonstrated that both a high polishing rate and a small surface roughness of the object after polishing could be achieved. Based on these findings, the present invention was completed.
本発明の研磨スラリーは、加工液と、前記加工液に分散された無数の研磨粒子とを有し、被研磨物を研磨するための研磨スラリーにおいて、
各前記研磨粒子は、平板状をなす無数の一次粒子と、各前記一次粒子を結合する結合材とからなる二次粒子を有し、
前記加工液は前記結合材を溶解しないことを特徴とする。
The polishing slurry of the present invention includes a machining liquid and countless abrasive particles dispersed in the machining liquid, and is a polishing slurry for polishing an object to be polished.
Each of the abrasive particles has secondary particles consisting of countless plate-shaped primary particles and a binder that binds each of the primary particles,
The processing liquid is characterized in that it does not dissolve the binder.
本発明の研磨スラリーでは、各一次粒子が結合した粒径の大きな二次粒子において、一次粒子が対抗する反力よりも大きな反力に対抗し、つまり適度な攻撃性を発揮し、高い研磨レートを実現できると推察される。この際、各一次粒子は平板状をなしているため、各一次粒子の縁部が切れ刃となる。また、各一次粒子は平板状をなしているため、大きな反力では割れ、反力に強く対抗しない。このため、作用点に作用する局所的な圧力を低減させつつ、一次粒子の結合によって切れ刃が作用する頻度が高く、良好な研磨性を発揮すると推察される。 In the polishing slurry of the present invention, the secondary particles having a large particle size in which each primary particle is combined resist a reaction force larger than the reaction force opposed by the primary particles, that is, exhibit moderate aggressiveness, and have a high polishing rate. It is assumed that this can be achieved. At this time, since each primary particle has a tabular shape, the edge of each primary particle becomes a cutting edge. Furthermore, since each primary particle has a tabular shape, it will crack under a large reaction force and will not strongly resist the reaction force. Therefore, it is presumed that while the local pressure acting on the point of application is reduced, the cutting edge acts more frequently due to the bonding of the primary particles, and good polishing performance is exhibited.
そして、二次粒子に対し、二次粒子が対抗できない大きな反力が作用すると、結合が解かれ、一次粒子を生じる。加工液は結合材を溶解しないため、二次粒子は反力以外の力によっては解かれない。このため、研磨後の被研磨物の表面粗さを小さくすることができる。また、被研磨物がスクラッチ等を生じ難い。 When a large reaction force, which the secondary particles cannot resist, acts on the secondary particles, the bonds are broken and primary particles are generated. Since the machining fluid does not dissolve the binder, the secondary particles are not loosened by forces other than reaction force. Therefore, the surface roughness of the polished object after polishing can be reduced. In addition, the object to be polished is less likely to be scratched.
したがって、本発明の研磨スラリーによれば、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとを両立することができる。 Therefore, according to the polishing slurry of the present invention, it is possible to achieve both a high polishing rate and a small surface roughness of the polished object after polishing.
本発明の研磨方法は、被研磨物と研磨体との間に研磨スラリーを介在させ、所定の面圧の下で前記被研磨物と前記研磨体とを相対移動させることにより、前記被研磨物を研磨する研磨方法において、
前記研磨スラリーは、加工液と、前記加工液に分散された無数の研磨粒子とを有し、
各前記研磨粒子は、平板状をなす無数の一次粒子と、各前記一次粒子を結合する結合材とからなる二次粒子を有し、
前記加工液は前記結合材を溶解しないことを特徴とする。
In the polishing method of the present invention, a polishing slurry is interposed between the workpiece to be polished and the polishing body, and the workpiece to be polished and the polishing body are relatively moved under a predetermined surface pressure. In the polishing method of polishing
The polishing slurry includes a machining liquid and countless abrasive particles dispersed in the machining liquid,
Each of the abrasive particles has secondary particles consisting of countless plate-shaped primary particles and a binder that binds each of the primary particles,
The processing liquid is characterized in that it does not dissolve the binder.
本発明の研磨方法では、本発明の研磨スラリーを用いているため、高い研磨レートと、研磨後の被研磨物における小さな表面粗さとを両立することができる。 Since the polishing method of the present invention uses the polishing slurry of the present invention, it is possible to achieve both a high polishing rate and a small surface roughness of the object to be polished after polishing.
加工液としては、被研磨物に応じ、分散媒と、添加剤とを採用することができる。分散媒としては、水の他、油、アルコール等を採用することができる。添加剤としては、分散剤、界面活性剤、酸化剤、塩化剤等を採用することができる。 As the processing fluid, a dispersion medium and additives can be used depending on the object to be polished. As the dispersion medium, in addition to water, oil, alcohol, etc. can be used. As additives, dispersants, surfactants, oxidizing agents, chlorinating agents, etc. can be employed.
本発明に係る研磨粒子は二次粒子を有している。二次粒子は、一次粒子と、各一次粒子を結合する結合材とからなる。一次粒子は、無機物であっても、有機物であっても、無機成分と有機成分とのハイブリッドであってもよい。無機物としては、シリカ、アルミナ、シリコンカーバイド、ジルコニア、セリア、ＣＢＮ、ダイヤモンド、ガラス等を採用することができる。有機物としては、メタクリル樹脂、フェノール樹脂、ユリア樹脂、メラミン樹脂、ポリスチレン、ポリアセタール、ポリカーボネート、アクリル等を採用することができる。無機成分と有機成分とのハイブリッドとしては、これら無機物の成分と有機物の成分とが任意で結合した粒子を採用することができる。本発明に係る研磨粒子は、二次粒子だけであってもよく、一次粒子を含んでいてもよい。 The abrasive particles according to the present invention have secondary particles. The secondary particles consist of primary particles and a binder that binds each primary particle. The primary particles may be inorganic, organic, or a hybrid of inorganic and organic components. As the inorganic material, silica, alumina, silicon carbide, zirconia, ceria, CBN, diamond, glass, etc. can be used. As the organic substance, methacrylic resin, phenol resin, urea resin, melamine resin, polystyrene, polyacetal, polycarbonate, acrylic, etc. can be employed. As a hybrid of an inorganic component and an organic component, particles in which these inorganic components and organic components are optionally combined can be used. The abrasive particles according to the present invention may be only secondary particles or may include primary particles.
本発明に係る一次粒子は平板状をなしている。平板状の一次粒子としては、アルミナの板状結晶粒等を採用することができる。また、薄板状に固化したガラスを粉砕したものを採用することもできる。 The primary particles according to the present invention have a tabular shape. As the plate-shaped primary particles, plate-shaped crystal grains of alumina or the like can be used. Further, it is also possible to use a material obtained by pulverizing glass that has been solidified into a thin plate.
加工液は結合材を溶解しないものとして選択される。加工液が水性、油性、アルコール質である場合には、結合材として、二酸化珪素を含むガラス質、金属等を採用することができる。加工液が水性である場合には、結合材として、樹脂等を採用することもできる。発明者らは、加工液が水であり、一次粒子はアルミナの板状結晶粒であり、結合材が二酸化珪素を含むガラス質である場合について効果を確認している。 The processing fluid is selected so as not to dissolve the binder. When the processing fluid is aqueous, oily, or alcoholic, a glassy substance containing silicon dioxide, metal, or the like can be used as the binder. When the processing fluid is aqueous, a resin or the like may be used as the binder. The inventors have confirmed the effect when the processing fluid is water, the primary particles are alumina plate-shaped crystal grains, and the binder is glassy containing silicon dioxide.
発明者らの試験結果によれば、各二次粒子は、ＢＥＴ比表面積が１．４９ｍ2／ｇ以上、２．１０ｍ2／ｇ以下であり、かつ、かさ密度が０．７０ｇ／ｃｍ3以上、０．９５ｇ／ｃｍ3以下であるであることが好ましい。この場合、研磨レートが十分高く、研磨後の被研磨物の表面粗さが十分小さい。 According to the inventors' test results, each secondary particle has a BET specific surface area of 1.49 m 2 /g or more and 2.10 m 2 /g or less, and a bulk density of 0.70 g/cm 3 or more. , 0.95 g/cm 3 or less. In this case, the polishing rate is sufficiently high and the surface roughness of the polished object after polishing is sufficiently small.
発明者らの試験結果によれば、被研磨物がＳｉウェハの場合、研磨スラリーを被研磨物のラップ加工に用いることで実用可能である。 According to the test results of the inventors, when the object to be polished is a Si wafer, it is practical to use the polishing slurry for lapping the object to be polished.
「試験」
以下の加工液及び研磨粒子を準備した。
（加工液）
分散媒：水
（研磨粒子）
実施例１：二次粒子（結合材は二酸化珪素を含むガラス質、ＢＥＴ比表面積は１．４９ｍ2／ｇ、かさ密度は０．７６ｇ／ｃｍ3）
実施例２：二次粒子（結合材は二酸化珪素を含むガラス質、ＢＥＴ比表面積は１．６４ｍ2／ｇ、かさ密度は０．９５ｇ／ｃｍ3）
実施例３：二次粒子（結合材は二酸化珪素を含むガラス質、ＢＥＴ比表面積は１．８４ｍ2／ｇ、かさ密度は０．７０ｇ／ｃｍ3）
実施例４：二次粒子（結合材は二酸化珪素を含むガラス質、ＢＥＴ比表面積は２．１０ｍ2／ｇ、かさ密度は０．７９ｇ／ｃｍ3）
比較例１：一次粒子（平均粒径３０μｍ、ＢＥＴ比表面積は０．２２ｍ2／ｇ、かさ密度は１．７６ｇ／ｃｍ3）
比較例２：一次粒子（平均粒径３μｍ、ＢＥＴ比表面積は１．８２ｍ2／ｇ、かさ密度は１．３０ｇ／ｃｍ3）
比較例３：二次粒子（結合材は二酸化珪素を含むガラス質、ＢＥＴ比表面積は１．１９ｍ2／ｇ、かさ密度は０．５０ｇ／ｃｍ3）
実施例１～４及び比較例３の二次粒子を構成する一次粒子はアルミナの板状結晶粒であり、比較例１、２の一次粒子はアルミナの粒状結晶粒である。各研磨粒子のＢＥＴ比表面積及びかさ密度を表１に示す。
"test"
The following machining liquid and abrasive particles were prepared.
(processing fluid)
Dispersion medium: water (abrasive particles)
Example 1: Secondary particles (binder is glassy containing silicon dioxide, BET specific surface area is 1.49 m 2 /g, bulk density is 0.76 g/cm 3 )
Example 2: Secondary particles (binder is glassy containing silicon dioxide, BET specific surface area is 1.64 m 2 /g, bulk density is 0.95 g/cm 3 )
Example 3: Secondary particles (binder is glassy containing silicon dioxide, BET specific surface area is 1.84 m 2 /g, bulk density is 0.70 g/cm 3 )
Example 4: Secondary particles (binder is glassy containing silicon dioxide, BET specific surface area is 2.10 m 2 /g, bulk density is 0.79 g/cm 3 )
Comparative Example 1: Primary particles (average particle size 30 μm, BET specific surface area 0.22 m 2 /g, bulk density 1.76 g/cm 3 )
Comparative Example 2: Primary particles (
Comparative Example 3: Secondary particles (binder is glassy containing silicon dioxide, BET specific surface area is 1.19 m 2 /g, bulk density is 0.50 g/cm 3 )
The primary particles constituting the secondary particles of Examples 1 to 4 and Comparative Example 3 are plate-shaped crystal grains of alumina, and the primary particles of Comparative Examples 1 and 2 are granular crystal grains of alumina. Table 1 shows the BET specific surface area and bulk density of each abrasive particle.
実施例３で用いた研磨粒子の１０００倍のＳＥＭ写真を図１に示す。また、実施例１～４及び比較例３で用いた研磨粒子の拡大模式図を図２に示す。図２に示すように、実施例１～４及び比較例３で用いた研磨粒子１は、平板状をなす無数の一次粒子３が結合した二次粒子である。この二次粒子は、一次粒子３と、各一次粒子３を結合する結合材５とからなる。結合材５は、ガラス質であり、水に溶解しない。
A SEM photograph of the abrasive particles used in Example 3 at a magnification of 1000 times is shown in FIG. Further, an enlarged schematic diagram of the abrasive particles used in Examples 1 to 4 and Comparative Example 3 is shown in FIG. As shown in FIG. 2, the abrasive particles 1 used in Examples 1 to 4 and Comparative Example 3 are secondary particles in which countless plate-shaped
加工液としての水に１０質量％の研磨粒子を混合し、実施例１～４及び比較例１～３の研磨スラリーを準備した。 Polishing slurries of Examples 1 to 4 and Comparative Examples 1 to 3 were prepared by mixing 10% by mass of abrasive particles with water as a processing fluid.
実施例１～４及び比較例１～３の研磨スラリーを用い、以下の加工試験条件でＳｉＣウェハを研磨加工して、研磨レート（μｍ／分）及び表面粗さ（Ｓａ）（ｎｍ）を調べた。 Using the polishing slurries of Examples 1 to 4 and Comparative Examples 1 to 3, SiC wafers were polished under the following processing test conditions, and the polishing rate (μm/min) and surface roughness (Sa) (nm) were examined. Ta.
＜試験条件＞
試験機：ウェハ研磨装置（Engis EJW-380）
ワーク（被研磨物）：ＳｉＣベアウェハ（４インチ）
加工圧：２０ｋＰａ
定盤／ワーク回転数：６０／６０ｒｐｍ
ラップ盤寸法：直径３０ｃｍ
研磨スラリーの供給量：１０ｍＬ/分
定盤に固定した研磨体：ポリウレタン系パッド
加工時間：３０分間
<Test conditions>
Testing machine: Wafer polishing equipment (Engis EJW-380)
Workpiece (object to be polished): SiC bare wafer (4 inches)
Processing pressure: 20kPa
Surface plate/work rotation speed: 60/60 rpm
Lap board dimensions: 30cm in diameter
Supply amount of polishing slurry: 10 mL/min Polishing body fixed on surface plate: Polyurethane pad Processing time: 30 minutes
研磨レートは、０．３μｍ／分以上を〇とし、０．２μｍ／分以上、０．３μｍ／分未満を△とし、０．２μｍ／分未満を×として評価した。表面粗さは、白色干渉顕微鏡（２００μｍ角視野のＳａ）にて、６５ｎｍ以下を〇とし、６５ｎｍ超、１１０ｎｍ以上を△とし、１１０超を×として評価した。また、加工中の研磨スラリーにおいて、研磨粒子の分散状態を目視で判断した。各研磨粒子が沈降して塊になっておれば×、各研磨粒子が沈降せずに分散しておれば〇として評価した。結果を表２に示す。 The polishing rate was evaluated as 0.3 μm/min or more as ○, 0.2 μm/min or more and less than 0.3 μm/min as Δ, and less than 0.2 μm/min as ×. The surface roughness was evaluated using a white interference microscope (Sa with a 200 μm square field of view) when 65 nm or less was rated as ○, when it was more than 65 nm and 110 nm or more, it was Δ, and when it was more than 110 was evaluated as ×. In addition, the dispersion state of the abrasive particles in the abrasive slurry during processing was visually determined. If each abrasive particle settled and became a lump, it was evaluated as ×, and if each abrasive particle was dispersed without settling, it was evaluated as ○. The results are shown in Table 2.
表２から、実施例１～４の研磨スラリーによれば、高い研磨レートと、研磨後のＳｉウェハにおける小さな表面粗さとを両立できることがわかる。換言すれば、実施例１～４の研磨スラリーを用いてＳｉウェハを研磨すれば、高い研磨レートと、研磨後のＳｉウェハにおける小さな表面粗さとの両立を行い易い。実施例１～４の研磨スラリー中の研磨粒子は、ＢＥＴ比表面積が１．４９ｍ2／ｇ以上、２．１０ｍ2／ｇ以下であり、かつ、かさ密度が０．７０ｇ／ｃｍ3以上、０．９５ｇ／ｃｍ3以下であることから、ＢＥＴ比表面積とかさ密度とがこれらの範囲であれば、研磨レートが十分高く、研磨後の被研磨物の表面粗さが十分小さいこともわかる。特に、実施例３、４の研磨スラリーによれば、研磨レートが十分高く、研磨後のＳｉウェハの表面粗さが十分小さい。 Table 2 shows that the polishing slurries of Examples 1 to 4 can achieve both a high polishing rate and a small surface roughness of the polished Si wafer. In other words, by polishing a Si wafer using the polishing slurries of Examples 1 to 4, it is easy to achieve both a high polishing rate and a small surface roughness of the Si wafer after polishing. The abrasive particles in the polishing slurries of Examples 1 to 4 have a BET specific surface area of 1.49 m 2 /g or more and 2.10 m 2 /g or less, and a bulk density of 0.70 g/cm 3 or more and 0. Since it is .95 g/cm 3 or less, it can be seen that if the BET specific surface area and bulk density are within these ranges, the polishing rate is sufficiently high and the surface roughness of the polished object after polishing is sufficiently small. In particular, according to the polishing slurries of Examples 3 and 4, the polishing rate was sufficiently high and the surface roughness of the Si wafer after polishing was sufficiently small.
また、実施例１～４の研磨スラリーでは、比較例１、２の研磨スラリーに比べ、研磨粒子が加工液内で長期間に亘って分散しており、研磨粒子が沈降し難いことがわかる。このため、実施例１～４の研磨スラリーは、分散剤を過度に加える必要がなく、研磨後の研磨スラリーの処理が容易になり、製造コストの低廉化を実現できるとともに、環境負荷も小さくすることが可能である。 Furthermore, in the polishing slurries of Examples 1 to 4, compared to the polishing slurries of Comparative Examples 1 and 2, the abrasive particles were dispersed in the processing fluid for a long period of time, and it was found that the abrasive particles were less likely to settle. Therefore, in the polishing slurries of Examples 1 to 4, there is no need to add an excessive amount of dispersant, making it easier to process the polishing slurry after polishing, reducing manufacturing costs and reducing environmental impact. Is possible.
以上において、本発明を実施例１～４に即して説明したが、本発明は上記実施例１～４に制限されるものではなく、その趣旨を逸脱しない範囲で適宜変更して適用できることはいうまでもない。 In the above, the present invention has been explained based on Examples 1 to 4, but the present invention is not limited to Examples 1 to 4, and can be applied with appropriate changes without departing from the spirit thereof. Needless to say.
本発明は半導体デバイスの製造方法、製造装置等に利用可能である。 INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing method of a semiconductor device, a manufacturing apparatus, etc.
１…研磨粒子
３…一次粒子
５…結合材
1...
Claims (5)
各前記研磨粒子は、平板状をなす無数の一次粒子と、各前記一次粒子を結合する結合材とからなる二次粒子を有し、
前記加工液は前記結合材を溶解しないことを特徴とする研磨スラリー。 A polishing slurry for polishing an object to be polished, which includes a machining fluid and countless abrasive particles dispersed in the machining fluid,
Each of the abrasive particles has secondary particles consisting of countless plate-shaped primary particles and a binder that binds each of the primary particles,
A polishing slurry characterized in that the processing liquid does not dissolve the binder.
前記一次粒子はアルミナの板状結晶粒であり、
前記結合材は、二酸化珪素を含むガラス質である請求項１記載の研磨スラリー。 the processing fluid is water;
The primary particles are plate-shaped crystal grains of alumina,
The polishing slurry according to claim 1, wherein the binder is vitreous containing silicon dioxide.
前記被研磨物のラップ加工に用いられる請求項１乃至３のいずれか１項記載の研磨スラリー。 The object to be polished is a Si wafer,
The polishing slurry according to any one of claims 1 to 3, which is used for lapping the object to be polished.
前記研磨スラリーは、加工液と、前記加工液に分散された無数の研磨粒子とを有し、
各前記研磨粒子は、平板状をなす無数の一次粒子と、各前記一次粒子を結合する結合材とからなる二次粒子を有し、
前記加工液は前記結合材を溶解しないことを特徴とする研磨方法。 A polishing method for polishing the object to be polished by interposing a polishing slurry between the object to be polished and the polishing body and relatively moving the object to be polished and the polishing body under a predetermined surface pressure,
The polishing slurry includes a machining liquid and countless abrasive particles dispersed in the machining liquid,
Each of the abrasive particles has secondary particles consisting of countless plate-shaped primary particles and a binder that binds each of the primary particles,
A polishing method characterized in that the processing liquid does not dissolve the binder.
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