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JP-7855523-B2 - Polishing composition for silicon wafers and its use

JP7855523B2JP 7855523 B2JP7855523 B2JP 7855523B2JP-7855523-B2

Inventors

  • 後藤 修
  • ▲高▼間 大輝
  • 土屋 公亮

Assignees

  • 株式会社フジミインコーポレーテッド

Dates

Publication Date
20260508
Application Date
20211124
Priority Date
20201130

Claims (9)

  1. It contains a basic compound, a surfactant, water, and a water-soluble polymer . The water-soluble polymer is one or more selected from the group consisting of modified polyvinyl alcohol, cellulose derivatives, and polymers containing nitrogen atoms. A polishing composition for silicon wafers, wherein the surfactant is a compound represented by the following formula (1). (In formula (1), R1 to R4 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R5 and R6 are each independently a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, m is an integer of 1 or more, n is an integer of 0 or more, and m + n ≤ 50.)
  2. It contains a basic compound, a surfactant, and water. A silicon wafer polishing composition wherein the surfactant is a compound represented by the following formula (1) and has a molecular weight of 300 or more. (In formula (1), R 1 ~R 4 Each is independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R 5 , R 6 Each of these is independently a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, m is an integer greater than or equal to 1, n is an integer greater than or equal to 0, and m + n ≤ 50.
  3. The silicon wafer polishing composition according to claim 2, wherein in formula (1), m and n satisfy 15 ≤ m + n ≤ 50.
  4. The silicon wafer polishing composition according to claim 2 or 3 , further comprising a water-soluble polymer.
  5. The polishing composition for silicon wafers according to any one of claims 1 to 4 , further comprising abrasive particles.
  6. The abrasive composition for silicon wafers according to claim 5 , comprising silica particles as the abrasive grains.
  7. The polishing composition for silicon wafers according to any one of claims 1 to 6 , wherein the pH of the polishing composition is 8.0 or more and 12.0 or less.
  8. A method for polishing a silicon wafer, comprising the step of polishing a silicon wafer using a silicon wafer polishing composition according to any one of claims 1 to 7 .
  9. A concentrated solution of the silicon wafer polishing composition according to any one of claims 1 to 7 .

Description

The present invention relates to a polishing composition for silicon wafers and a method for polishing silicon wafers using the polishing composition. This application claims priority to Japanese Patent Application No. 2020-198395, filed on 30 November 2020, the entire contents of which are incorporated herein by reference. Conventionally, precision polishing has been performed on the surfaces of materials such as metals, metalloids, nonmetals, and their oxides using polishing compositions. For example, the surface of a silicon wafer used as a component of semiconductor products is generally finished to a high-quality mirror surface through a lapping process (rough polishing process) and a polishing process (precision polishing process). The above polishing process typically includes a pre-polishing process (preliminary polishing process) and a finish polishing process (final polishing process). Japanese Patent Application Publication No. 2008-147651 Preferred embodiments of the present invention will be described below. Matters other than those specifically mentioned herein but necessary for carrying out the present invention can be understood as design matters for those skilled in the art based on the prior art. The present invention can be carried out based on the contents disclosed herein and common technical knowledge in the art. <Surfactant A> The polishing composition disclosed herein is characterized by containing a surfactant (hereinafter also referred to as "surfactant A" for convenience) which is an acetylene glycol type compound having one acetylene group in one molecule and further having an alkylene oxide added to it. Polishing using the polishing composition containing surfactant A of the above specific structure allows for good chemical polishing action by the basic compound described later, and maintains or improves the surface quality of the polished surface. This is because surfactant A of the above specific structure, by simultaneously having an acetylene structure and an alkylene oxide structure, protects the substrate surface without excessively suppressing alkaline etching by the basic compound. The action of surfactant A is not limited to the above action. From the viewpoint of improving surface quality, a nonionic surfactant A is more preferable as surfactant A. Surfactant A can be used alone or in combination of two or more types. A preferred example of surfactant A is a compound represented by the following general formula (1). In formula (1) above, R1 to R4 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. The number of carbon atoms in the alkyl groups R1 to R4 may be 1 or more, 2 or more, 3 or more, 20 or less, 18 or less, 16 or less, 12 or less, 10 or less, 8 or less, or 5 or less. Specific examples of alkyl groups include methyl group, ethyl group, propyl group, iso-propyl group, butyl group, iso-butyl group, sec-butyl group, tert-butyl group, pentyl group, iso-pentyl group, neo-pentyl group, tert-pentyl group, hexyl group, octyl group, nonyl group, decyl group, lauryl group, myristyl group, palmityl group, stearyl group, etc. R1 to R4 may be the same or different. In formula (1) above, R5 and R6 are each independently a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms. The number of carbon atoms in the alkylene groups that become R5 and R6 may be 1 or more, 2 or more, 3 or more, 4 or less, or 3 or less. Specific examples of alkylene groups include ethylene, propylene, butylene, and pentylene groups. R5 and R6 may be the same or different. In equation (1) above, m is an integer greater than or equal to 1, n is an integer greater than or equal to 0, and m + n ≤ 50. m + n may be greater than or equal to 1, greater than or equal to 3, greater than or equal to 5, greater than or equal to 10, greater than or equal to 15, greater than or equal to 20, and may be less than or equal to 50, less than or equal to 30, less than or equal to 22, less than or equal to 16, less than or equal to 12, less than or equal to 8, or less than or equal to 4 (for example, less than or equal to 3). m and n may be the same or different. Furthermore, since it is difficult to completely control m and n in the above formula (1), surfactant A can be used in a manner that includes multiple compounds with different m+n values. Also, surfactant A can be used in a manner that further includes a compound having the structure m=n=0. In these cases, the average value of m+n (hereinafter also referred to as the "average number of added moles") may be 1 or more, 3 or more, 5 or more, 10 or more, 15 or more, 20 or more, 50 or less, 30 or less, 22 or less, 16 or less, 12 or less, 8 or less, or 4 or less (for example, 3 or less). The surfactant A used has a suitable molecular weight that exerts its effect in the abrasive composition and is not limited to a specific molecular weight. The molecular weight of surfactant A is typically 25