METHOD FOR FORMING IDENTIFICATION MARKS ON REFRACTORY MATERIAL SINGLE CRYSTAL SUBSTRATE, AND REFRACTORY MATERIAL SINGLE CRYSTAL SUBSTRATE

• US 20140017447A1
• Filed: 07/09/2013
• Published: 01/16/2014
• Est. Priority Date: 07/10/2012
• Status: Active Grant

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: KONDO, Sadahiko
• Granted Patent: US 9,318,443 B2
• Time in Patent Office: Days
• US Class Current: 428/141
• CPC Class Codes: B29C 59/16 by wave energy or particle radiation , e.g. infrared heating B29C59/007 takes precedence
• CPC Class Codes: C30B 29/20 Aluminium oxides
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: H01L 2223/54433 containing identification or tracking information
• CPC Class Codes: H01L 2223/54453 for use prior to dicing
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]

Abstract

An identification mark formation method for forming an identification mark on a refractory material single crystal substrate that is made of one selected from the group consisting of sapphire, gallium nitride, aluminum nitride, diamond, boron nitride, zinc oxide, gallium oxide, and titanium dioxide is disclosed. The method includes: (a) scanning a principal surface of the refractory material single crystal substrate with a laser beam at a first energy density such that a groove is formed in the principal surface of the refractory material single crystal substrate, thereby forming an identification mark in the principal surface of the refractory material single crystal substrate; and (b) scanning an inside of the groove of the refractory material single crystal substrate with a laser beam at a second energy density that is lower than the first energy density.

Claims

1. A method for forming an identification mark on a refractory material single crystal substrate, the refractory material single crystal substrate being made of a single crystal which is formed by one selected from the group consisting of sapphire, gallium nitride, aluminum nitride, diamond, boron nitride, zinc oxide, gallium oxide, and titanium dioxide, the method comprising:

(a) scanning a principal surface of the refractory material single crystal substrate with a laser beam at a first energy density such that a groove is formed in the principal surface of the refractory material single crystal substrate, thereby forming an identification mark which is constituted of one or more grooves in the principal surface of the refractory material single crystal substrate; and

(b) scanning an inside of the groove formed in the principal surface of the refractory material single crystal substrate with a laser beam at a second energy density that is lower than the first energy density.

2. The method of claim 1, wherein a width of the groove is not less than 50 μ

m, and a depth of the groove is not less than 10 μ

m.

3. The method of claim 1, wherein the surface roughness Ra of an internal surface of the groove is not more than 1 μ

m.

4. The method of claim 1, further comprising

(c) after step (b), performing mechanical polishing on the principal surface of the refractory material single crystal substrate.

5. The method of claim 4 wherein, after step (c), gas phase etching is performed on the principal surface of the refractory material single crystal substrate.

6. The method of claim 1, wherein the surface roughness Ra of the principal surface of the refractory material single crystal substrate is not less than 0.1 nm and not more than 2.0 nm.

7. A refractory material single crystal substrate which has an identification mark on a principal surface, the identification mark being constituted of one or more grooves, and the refractory material single crystal substrate being made of a single crystal which is formed by one selected from the group consisting of sapphire, gallium nitride, aluminum nitride, diamond, boron nitride, zinc oxide, gallium oxide, and titanium dioxide,

wherein a width of the groove is not less than 50 μ

m and less than 0.5 mm, and a depth of the groove is not less than 10 μ

m, and

a surface roughness Ra of an internal surface of the groove is not more than 1 μ

m.

8. The refractory material single crystal substrate of claim 7, wherein the surface roughness Ra of the principal surface is not less than 0.1 nm and not more than 2.0 nm.

9. The refractory material single crystal substrate of claim 7, wherein a bottom surface of the groove is a solidified surface.

10. The refractory material single crystal substrate of claim 9, wherein the bottom surface of the groove has a striped pattern.

11. The refractory material single crystal substrate of claim 8, wherein a bottom surface of the groove is a solidified surface.

12. The refractory material single crystal substrate of claim 11, wherein the bottom surface of the groove has a striped pattern.