Semiconductor device and its manufacturing method

• US 6,468,902 B2
• Filed: 01/24/2001
• Issued: 10/22/2002
• Est. Priority Date: 05/28/1998
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kawai, Hiroji
• Primary Examiner(s): Fourson, George
• Assistant Examiner(s): GARCIA, JOANNIE A
• Application Number:
  US09/768,480
• Publication Number:
  US 20010040245A1
• Time in Patent Office: 636 Days
• Field of Search: 438/47, 438/149, 438/151, 438/459, 438/667, 438/708, 438/734, 438/745, 438/940, 438/977, 438/FOR.117, 438/FOR.344, 438/FOR.333
• US Class Current: 438/667
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/0332 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/304 Mechanical treatment, e.g. grinding, polishing, cutting H01L21/30625 takes precedence
• CPC Class Codes: H01L 21/30612 Etching of AIIIBV compounds
• CPC Class Codes: H01L 21/76898 formed through a semiconductor substrate
• CPC Class Codes: H01L 29/66522 with an active layer made of a group 13/15 material H01L29/66446 takes precedence
• CPC Class Codes: H01L 29/812 with a Schottky gate H01L29/7725, H01L29/775, H01L29/778, H01L29/806 take precedence; with Schottky contact on top of heterojunction gate H01L29/802
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01S 2301/173 The laser chip comprising special buffer layers, e.g. dislocation prevention or reduction
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/0207 Substrates having a special shape
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/0217 Removal of the substrate
• CPC Class Codes: H01S 5/04254 characterised by the shape
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
• CPC Class Codes: Y10S 438/94 Laser ablative material removal

Abstract

After making a GaN FET by growing GaN semiconductor layers on the surface of a sapphire substrate, the bottom surface of the sapphire substrate is processed by lapping, using an abrasive liquid containing a diamond granular abrasive material and reducing the grain size of the abrasive material in some steps, to reduce the thickness of the sapphire substrate to 100 μm or less. Thereafter, the bottom surface of the sapphire substrate is processed by etching using an etchant of phosphoric acid or phosphoric acid/sulfuric acid mixed liquid to remove a strained layer by lapping followed by making a via hole by etching the bottom surface of the sapphire substrate by using a similar etchant.

Claims

1. A manufacturing method of a semiconductor device having a single-crystal substrate made of a material different from nitride III-V compound semiconductors and a first device made on a first surface of the single-crystal substrate by using III-V compound semiconductors, in which electrical connection to the first device is made through a via hole formed in the single-crystal substrate, comprising the step of:

forming the via hole by selectively etching a second surface of the single-crystal substrate by using an etchant containing phosphoric acid or phosphoric acid and sulfuric acid heated to 150 through 450°

C.

2. The manufacturing method of a semiconductor device according to claim 1 wherein an etching mask made of a first mask film of Cr, Ti or Ni and a second mask film of Pt, Pd or Au thereon is made on the second surface of the single-crystal substrate, and the via hole is made by etching the second surface of the single-crystal substrate using the etching mask.

3. The manufacturing method of a semiconductor device according to claim 1 wherein the second surface of the single-crystal substrate is etched by immersing only the second surface of the single-crystal substrate into the etchant.

4. The manufacturing method of a semiconductor device according to claim 1 wherein the single-crystal substrate is a sapphire substrate, spinel substrate, perovskite yttrium aluminate substrate or SiC substrate.

5. The manufacturing method of a semiconductor device according to claim 1 wherein the semiconductor device is a semiconductor laser using nitride III-V compound semiconductors.

6. The manufacturing method of a semiconductor device according to claim 1 wherein the semiconductor device is a FET using nitride III-V compound semiconductors.

7. A manufacturing method of a semiconductor device having a single-crystal substrate made of a material different from nitride III-V compound semiconductors and a first device made on a first surface of the single-crystal substrate by using III-V compound semiconductors, in which electrical connection to the first device is made through a via hole formed in the single-crystal substrate, comprising the steps of:

making a hole as deep as 10 μ

m or more but not reaching the first surface of the substrate by selectively irradiating laser light having a wavelength not shorter than 6 μ

m onto a second surface of the single-crystal substrate; and

making the via hole by etching the second surface of the single-crystal substrate by using an etchant containing phosphoric acid or phosphoric acid and sulfuric acid heated to 150 through 450°

C. so as to make the hole reach the first surface of the substrate.

8. The manufacturing method of a semiconductor device according to claim 7 wherein pulse laser light having the wavelength of 10.6 μ

m from a CO₂ laser is used as the laser light.

9. The manufacturing method of a semiconductor device according to claim 7 wherein the single-crystal substrate is a sapphire substrate, spinel substrate, perovskite yttrium aluminate substrate or SiC substrate.

10. The manufacturing method of a semiconductor device according to claim 7 wherein the semiconductor device is a semiconductor laser using nitride III-V compound semiconductors.

11. The manufacturing method of a semiconductor device according to claim 7 wherein the semiconductor device is a FET using nitride III-V compound semiconductors.