Method of etching substrates

• US 20030190770A1
• Filed: 04/09/2002
• Published: 10/09/2003
• Est. Priority Date: 04/09/2002
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: Oriol, Inc.
• Inventors: Kim, Dong-woo, Sung, Youn-joon, Yeom, Geun-young, Urbanek, Wolfram, Yoo, Myung cheol, Jeong, Chang-hyun, Kim, Kyong-nam
• Granted Patent: US 6,818,532 B2
• Time in Patent Office: Days
• US Class Current: 438/113
• CPC Class Codes: C30B 29/20 Aluminium oxides
• 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 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination

Abstract

Thinning and dicing substrates using inductively coupled plasma reactive ion etching (ICP RIE). When dicing, a hard photo-resist pattern or metal mask pattern that defines scribe lines is formed on a sapphire substrate or on a semiconductor epitaxial layer, beneficially by lithographic techniques. Then, the substrate is etched along the scribe lines to form etched channels. An etching gas comprised of BCl₃ and/or BCl₃/Cl₂ gas is used (optionally, Ar can be added). Stress lines are then produced through the substrate along the etched channels. The substrate is then diced along the stress lines. When thinning, a surface of a substrate is subjected to inductively coupled plasma reactive ion etching (ICP RIE) using BCl₃ and/or BCl₃/Cl₂ gas, possibly with some Ar. ICP RIE is particularly useful when working sapphire and other hard substrates.

Claims

1. A method of separating individual semiconductor devices from a substrate, comprising:

procuring a substrate having a plurality of at least partially formed individual semiconductor devices;

forming a mask pattern having scribe lines over the substrate, wherein the scribe lines expose the substrate to reactive ion etching while the remainder of the mask pattern protects the substrate;

etching trenches in the substrate and along the scribe lines using inductively coupled plasma reactive ion etching (ICP RE); and

stressing the substrate to produce stress lines and separation of the substrate at the trenches to dice out at least one of the plurality of at least partially formed individual semiconductor devices.

2. The method of claim 1, wherein ICP RIE is performed using a reaction gas containing BCl₃.

3. The method of claim 2, wherein the reaction gas further contains Cl₂.

4. The method of claim 2, wherein the reaction gas further contains Ar.

5. The method of claim 1, wherein etching trenches produces trenches with notches.

6. The method of claim 1, wherein the step of forming the mask pattern includes forming a metal layer.

7. The method of claim 6, wherein the metal layer includes Cr.

8. The method of claim 6, wherein the metal layer includes Mo.

9. The method of claim 1, wherein the step of forming the mask pattern includes forming a photo-resist layer.

10. The method of claim 1, wherein the step of procuring a substrate includes obtaining a sapphire substrate having GaN semiconductor layers.

11. The method of claim 1, wherein the step of procuring a substrate includes obtaining a SiC containing substrate.

12. The method of claim 1, wherein the step of stressing the substrate includes rolling the substrate with a roller.

13. The method of claim 1, wherein the step of stressing the substrate includes forcing a knife-edge toward the trenches.

14. A method of forming semiconductor devices, comprising:

procuring a substrate;

forming a plurality of individual semiconductor devices on the substrate;

forming a mask pattern having scribe lines over the substrate, wherein the scribe lines expose the substrate between the individual semiconductor devices to reactive ion etching while the remainder of the mask pattern protects the substrate;

etching trenches in the substrate and along the scribe lines using inductively coupled plasma reactive ion etching (ICP RIE); and

stressing the substrate to produce stress lines and separation of the substrate at the trenches to dice out at a plurality of individual semiconductor devices.

15. The method of claim 14, wherein ICP RIE is performed using a reaction gas containing BCl₃.

16. The method of claim 15, wherein the reaction gas further contains Cl₂.

17. The method of claim 16, wherein the reaction gas further contains Ar.

18. The method of claim 15, wherein etching trenches produces trenches with notches.

19. The method of claim 14, wherein the step of forming the mask pattern includes forming a metal layer.

20. The method of claim 19, includes a metal from a group consisting of Cr and Mo.

21. The method of claim 14, wherein the step of forming the mask pattern includes forming a photo-resist layer.

22. The method of claim 14, wherein the step of procuring a substrate includes obtaining a substrate from a group consisting of sapphire, SiC, Si GaAs, InP, ZnSe, ZnO, and GaP.

23. The method of claim 22, wherein the step of forming a plurality of individual semiconductor devices includes forming a GaN containing semiconductor layer.

24. The method of claim 14, wherein the step of stressing the substrate includes rolling the substrate with a roller.

25. The method of claim 14, wherein the step of stressing the substrate includes forcing a knife-edge toward the trenches.

26. The method of claim 14, wherein the step of step of forming the mask pattern forms a mask pattern that is greater than 6 μ

m thick.

27. A method of forming semiconductor devices, comprising:

procuring a sapphire substrate;

forming a plurality of individual GaN semiconductor devices on the sapphire substrate;

forming a mask pattern having scribe lines over the sapphire substrate, wherein the scribe lines expose the sapphire substrate between the individual GaN semiconductor devices to reactive ion etching while the remainder of the mask pattern protects the sapphire substrate;

etching trenches in the sapphire substrate and along the scribe lines using inductively coupled plasma reactive ion etching (ICP RIE); and

stressing the sapphire substrate to produce stress lines and separation of the sapphire substrate at the trenches to dice out at a plurality of individual GaN semiconductor devices.

28. The method of claim 27, wherein ICP RIE is performed using a reaction gas containing BCl₃.

29. The method of claim 28, wherein the reaction gas further contains Cl₂.

30. The method of claim 28, wherein the reaction gas further contains Ar.

31. The method of claim 27, wherein etching trenches produces trenches with notches.

32. The method of claim 27, wherein the step of forming the mask pattern includes forming a metal layer.

33. The method of claim 32, the mask pattern includes depositing a metal from a group consisting of Cr and Mo.

34. The method of claim 32, wherein the step of forming the mask pattern includes forming a photo-resist layer.

35. The method of claim 27, wherein the individual GaN semiconductor devices are LEDs.

36. The method of claim 27, wherein the step of stressing the sapphire substrate includes rolling the sapphire substrate with a roller.

37. The method of claim 27, wherein the step of stressing the sapphire substrate includes forcing a knife-edge toward the trenches.

38. The method of claim 37, wherein the step of step of forming the mask pattern forms the mask pattern on a side of the sapphire substrate that is opposite a side having individual GaN semiconductor devices.

39. The method of claim 27, wherein the step of forming the mask pattern forms a mask pattern that is greater than 6 μ

m thick.

40. A method of thinning a substrate comprising:

locating a substrate on an electrode in a reactive ion chamber;

evacuating the chamber;

applying RF power and a DC bias to the electrode; and

etching the substrate by inductively coupled plasma reactive ion etching using an etching gas comprised of BCl₃.

41. The method of claim 40, wherein the etching gas further includes Cl₂.

42. The method of claim 41, wherein the etching gas further includes Ar.

43. The method of claim 42, wherein the etching gas is comprised of 20%Ar/40%Cl₂/40%BCl₃.

44. The method of claim 40, wherein the RF is about 800W of inductive power.

45. The method of claim 40, wherein the DC bias is about −

300V.

46. The method of claim 40, wherein the chamber is evacuated to about 4.0 Pa.

47. The method of claim 40, wherein a sapphire substrate is located in the reactive ion chamber.