Surface machining method for single crystal SiC substrate, manufacturing method thereof, and grinding plate for surface machining single crystal SiC substrate

• US 9,620,374 B2
• Filed: 02/13/2014
• Issued: 04/11/2017
• Est. Priority Date: 02/13/2013
• Status: Active Grant

• Current Assignee: Resonac Corp. (Resonac Holdings Corp.)
• Original Assignee: Showa Denko KK
• Inventors: Kido, Takanori, Kato, Tomohisa
• Primary Examiner(s): Lu, Jiong-Ping
• Application Number:
  US14/765,875
• Publication Number:
  US 20160035579A1
• Time in Patent Office: 1,153 Days
• Field of Search: None
• CPC Class Codes: B24B 37/245 Pads with fixed abrasives
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: C30B 33/00 After-treatment of single crystals or homogeneous polycrystalline material with defined structure C30B31/00 takes precedence
• CPC Class Codes: H01L 21/02013 Grinding, lapping
• CPC Class Codes: H01L 21/02024 Mirror polishing
• CPC Class Codes: H01L 21/30625 With simultaneous mechanical treatment, e.g. mechanico-chemical polishing
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 29/1608 Silicon carbide

Abstract

A surface machining method for a single crystal SiC substrate, including: a step of mounting a grinding plate which includes a soft pad and a hard pad sequentially attached onto a base metal having a flat surface, a step of generating an oxidation product by using the grinding plate, and a step of grinding the surface while removing the oxidation product, wherein abrasive grains made of at least one metallic oxide that is softer than single crystal SiC and has a bandgap are fixed to the surface of the hard pad.

Claims

1. A surface machining method for a single crystal SiC substrate, comprising:

a step of mounting a grinding plate which includes a first pad and a second pad harder than said first pad sequentially attached onto a base metal having a mounting surface,

a step of generating an oxidation product by using the grinding plate, and

a step of grinding a surface of the single crystal SiC substrate while removing the oxidation product,

wherein abrasive grains made of at least one metallic oxide that is softer than single crystal SiC and has a bandgap are fixed to a grinding surface of the second pad, and wherein a rotation direction of a table for a substance to be machined in the inverse direction of the rotation direction of the grinding plate, the second pad is segmented, and the rotation speed of the table for a substance to be machined is in a range of 30 rpm to 300 rpm.

2. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein pure water is used as a coolant.

3. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein a coolant is not used or the supply rate of pure water used as the coolant is greater than 0 ml/min and less than or equal to 100 ml/min.

4. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein the metal oxide is one or more selected from cerium oxide, titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, zinc oxide, and tin oxide.

5. The surface machining method for a single crystal SiC substrate according to claim 4,

wherein the metal oxide includes at least cerium oxide.

6. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein the abrasive grains have a specific surface area in a range of 0.1 m²/g to 300 m²/g.

7. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein the first pad is a non-woven fabric or suede-based pad.

8. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein the second pad is a foamed polyurethane-based pad.

9. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein the abrasive grains are fixed by using a binding agent and/or an adhesive.

10. The surface machining method for a single crystal SiC substrate according to claim 1,

wherein the abrasive grains are fixed by attaching an abrasive grain-fixed film to the hard pad.

11. A manufacturing method for machining a single crystal SiC substrate, comprising:

a step of mounting a grinding plate which includes a first pad and a second pad harder than said first pad sequentially attached onto a base metal having a mounting surface,

a step of generating an oxidation product by using the grinding plate, and

a step of grinding a surface of the single crystal SiC substrate while removing the oxidation product,

wherein abrasive grains made of at least one metallic oxide that is softer than single crystal SiC and has a bandgap are fixed to a grinding surface of the second pad, wherein a rotation direction of a table for a substance to be machined is the inverse direction of the rotation direction of the grinding plate, the second pad is segmented, and the rotation speed of the table for a substance to be machined is in a range of 30 rpm to 300 rpm, and wherein the surface of the single crystal SiC substrate to be ground is a C plane of a (0001) plane of the SiC substrate.