Integrated process for etching and cleaning oxide surfaces during the manufacture of microelectronic devices

• US 20030087532A1
• Filed: 11/01/2001
• Published: 05/08/2003
• Est. Priority Date: 11/01/2001
• Status: Abandoned Application

• Current Assignee: FSI International, Inc. (Tokyo Electron Limited)
• Original Assignee: FSI International, Inc. (Tokyo Electron Limited)
• Inventors: Smith, Eugene, Wu, Biao, Olson, Erik David, Krishnaswamy, Ramkumar
• Application Number:
  US10/001,933
• Publication Number:
  US 20030087532A1
• Time in Patent Office: Days
• US Class Current: 438/745
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31138 by dry-etching

Abstract

The present invention provides integrated systems and methods for carrying out manufacturing steps relating to etching, photoresist stripping and optionally, particle removal. More specifically, the present invention provides integrated systems and methods which may be utilized to etch oxide with subsequent removal of photoresist using BOE solutions that are desirably blended on-line. Advantageously, systems and methods embodying features of the present invention include a single process chamber so that cycle time and individual step processing time are reduced, further resulting in increased productivity of the systems and methods.

Claims

1. A method of treating an in-process microelectronic device precursor, wherein the precursor comprises a substrate, a first oxide layer over at least a portion of the substrate and a patterned photoresist over the first oxide layer and exposing one or more portions of the first oxide layer, comprising the steps of:

(a) causing a first etchant comprising aqueous HF and a buffering amount of a fluoride salt to etch one or more of the exposed portions of the first oxide layer to expose one or more portions of the substrate; and

(b) causing a first oxidant comprising ozone to strip at least a portion of the patterned photoresist, and to form a second oxide layer on the portions of the substrate exposed by the etching step.

2. The method of claim 1, wherein the fluoride salt comprises ammonium fluoride.

3. The method of claim 1, wherein at least substantially all of the exposed portions of the first oxide layer are removed.

4. The method of claim 1, further comprising the step of providing a first etchant, prior to step (a), wherein the first etchant is provided by blending on-line ingredients comprising aqueous ammonium hydroxide and a molar excess of hydrofluoric acid in deionized water.

5. The method of claim 4, wherein the ammonium hydroxide is 29 weight percent aqueous ammonium hydroxide.

6. The method of claim 5, wherein the hydrofluoric acid is 49 weight percent aqueous hydrofluoric acid.

7. The method of claim 6, wherein the ammonium hydroxide is provided at a flow rate of from about 15 ml/min to about 300 ml/min, the hydrofluoric acid is provided at a flow rate of from about 15 ml/min to about 300 ml/min and the deionized water is provided at a flow rate of from about 500 ml/min to about 3000 ml/min.

8. The method of claim 1, further comprising a rinse step prior to step (b).

9. The method of claim 1, wherein the oxidant comprises ozone gas co-introduced with deionized water.

10. The method of claim 1, wherein the oxidant comprises ozonated water.

11. The method of claim 10, wherein the ozonated water comprises from about 1 ppm to about 500 ppm ozone.

12. The method of claim 11, wherein the ozonated water comprises from about 50 ppm to about 120 ppm ozone.

13. The method of claim 1, wherein the oxidant strips substantially all of the patterned photoresist.

14. A method of treating an in-process microelectronic device precursor, wherein the precursor comprises a substrate, a first oxide layer over at least a portion of the substrate and a patterned photoresist over the first oxide layer and exposing one or more portions of the first oxide layer, comprising the steps of

a. causing a first etchant to etch one or more of the exposed portions of the first oxide layer;

b. causing a first oxidant to strip at least a portion of the patterned photoresist, and to form a second oxide layer on the portions of the substrate exposed by the etching step; and

c. causing a second etchant to contact the device precursor under conditions effective to selectively remove at least a portion of the second oxide layer relative to the first oxide layer.

15. The method of claim 14, wherein the first etchant comprises an aqueous acid.

16. The method of claim 15, wherein the first etchant comprises aqueous hydrofluoric acid.

17. The method of claim 15, wherein the etchant further comprises a salt of the aqueous acid.

18. The method of claim 14, wherein the first etchant comprises a combination of etchants.

19. The method of claim 18, wherein the combination of etchants is caused to etch one or more of the exposed portions of the first oxide layer simultaneously.

20. The method of claim 18, wherein the combination of etchants is caused to etch one or more of the exposed portions of the first oxide layer in succession.

21. The method of claim 18, wherein the combination of etchants is caused to etch one or more of the exposed portions of the first oxide layer in an overlapping fashion.

22. The method of claim 14, wherein the first oxidant comprises a combination of oxidants.

23. The method of claim 22, wherein the combination of oxidants contact the substrate simultaneously.

24. The method of claim 22, wherein the combination of oxidants is caused to contact the substrate in succession.

25. The method of claim 22, wherein the combination of oxidants is caused to contact the substrate in an overlapping fashion.

26. The method of claim 14, wherein the oxidant comprises SPM chemistry, APM chemistry, ozone gas, ozonated water, or a combination of these.

27. The method of claim 14, wherein the second etchant removes substantially all of the second oxide layer.

28. The method of claim 14, wherein the second etchant comprises dilute, aqueous hydrofluoric acid.

29. The method of claim 28, wherein the second etchant comprises an aqueous solution of less than 5 weight percent hydrofluoric acid.

30. The method of claim 29, wherein the second etchant comprises an aqueous solution of less than 1 weight percent hydrofluoric acid.

31. The method of claim 30, wherein the second etchant comprises an aqueous solution of from about 0.01 weight percent to about 3 weight percent hydrofluoric acid.

32. The method of claim 31, wherein the second etchant comprises an aqueous solution of from about 0.1 weight percent to about 1 weight percent hydrofluoric acid.

33. A method of treating an in-process microelectronic device precursor, wherein the precursor comprises a substrate, a first oxide layer over at least a portion of the substrate and a patterned photoresist over the first oxide layer and exposing one or more portions of the first oxide layer, comprising the steps of

a. causing a first etchant comprising aqueous HF and a buffering amount of a fluoride salt to etch one or more of the exposed portions of the first oxide layer to expose one or more portions of the substrate;

b. causing a first oxidant comprising ozone to strip at least a portion of the patterned photoresist, and to form a second oxide layer on the portions of the substrate exposed by the etching step; and

c. causing a second etchant comprising HF to contact the device precursor under conditions effective to selectively remove at least a portion of the second oxide layer relative to the first oxide layer.

34. A method of treating an in-process microelectronic device precursor, wherein the precursor comprises a substrate, a first oxide layer over at least a portion of the substrate and a patterned photoresist over the first oxide layer and exposing one or more portions of the first oxide layer, comprising the steps of

a. causing a first etchant to etch one or more of the exposed portions of the first oxide layer to expose one or more portions of the substrate;

b. causing a first oxidant to strip at least a portion of the patterned photoresist, and to form a second oxide layer on the portions of the substrate exposed by the etching step;

c. causing a second etchant to contact the device precursor under conditions effective to selectively remove at least a portion of the second oxide layer relative to the first oxide layer; and

d. causing a second oxidant to contact the device precursor under conditions effective to cause a third oxide layer to form on the device precursor.

35. The method of claim 34, wherein the third oxide layer is substantially devoid of metallic impurities.

36. The method of claim 34, wherein the second oxidant comprises ozone, ozonated water, deionized water, or a combination of these.

37. The method of claim 34, wherein the second oxidant comprises ozone gas co-introduced with deionized water.

38. The method of claim 34, wherein at least steps (a) and (b) are carried out within a single process chamber.

39. The method of claim 38, wherein at least steps (a), (b) and (c) are carried out within a single process chamber.

40. The method of claim 39, wherein at least steps (a), (b), (c) and (d) are carried out within a single process chamber.

41. The method of claim 34, wherein at least steps (b) and (c) are carried out within a single process chamber.

42. The method of claim 34, wherein at least steps (c) and (d) are carried out within a single process chamber.

43. The method of claim 34, wherein at least steps (b)(c) and (d) are carried out within a single process chamber.

44. A method of treating an in-process microelectronic device precursor, wherein the precursor comprises a substrate, a first oxide layer over at least a portion of the substrate and a patterned photoresist over the first oxide layer and exposing one or more portions of the first oxide layer, comprising the steps of

a. causing a first etchant comprising aqueous HF and a buffering amount of a fluoride salt to etch one or more of the exposed portions of the first oxide layer to expose one or more portions of the substrate;

b. causing a first oxidant comprising ozone to strip at least a portion of the patterned photoresist, and to form a second oxide layer on the portions of the substrate exposed by the etching step;

c. causing a second etchant comprising HF to contact the device precursor under conditions effective to selectively remove at least a portion of the second oxide layer relative to the first oxide layer; and

d. causing a second oxidant comprising ozone to contact the device precursor under conditions effective to cause a third oxide layer to form on the device precursor.