Methods Of Forming Patterns Utilizing Lithography And Spacers

• US 20100093175A1
• Filed: 10/09/2008
• Published: 04/15/2010
• Est. Priority Date: 10/09/2008
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Kiehlbauch, Mark, Niroomand, Ardavan, Sandhu, Gurtej S., Sills, Scott
• Granted Patent: US 8,039,399 B2
• Time in Patent Office: Days
• US Class Current: 438/694
• CPC Class Codes: H01L 21/0273 characterised by the treatment of photoresist layers
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/0338 Process specially adapted to improve the resolution of the mask
• CPC Class Codes: H10B 69/00 Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices

Abstract

Some embodiments include methods of forming patterns. A first set of features is photolithographically formed over a substrate, and then a second set of features is photolithographically formed over the substrate. At least some of the features of said second set alternate with features of the first set. Spacer material is formed over and between the features of the first and second sets. The spacer material is anisotropically etched to form spacers along the features of the first and second sets. The features of the first and second sets are then removed to leave a pattern of the spacers over the substrate.

Claims

1. A method of forming a pattern, comprising:

lithographically forming a first set of masking features over a substrate, a pair of features of the first set being adjacent to one another and being spaced from one another by a first gap;

lithographically forming a second set of masking features over the substrate, at least one of the features of said second set being within the gap between the adjacent features of the first set;

the masking features of the first and second sets being a plurality discrete features separated from one another by intervening spaces;

forming spacer material over and between the masking features of the first and second sets;

anisotropically etching the spacer material to form spacers along the masking features of the first and second sets; and

removing the masking features of the first and second sets to leave a pattern of the spacers over the substrate.

2. The method of claim 1 wherein the first and second sets of masking features are first and second sets of photoresist features, respectively, and further comprising laterally trimming photoresist of the first set of photoresist features prior to forming the second set of photoresist features.

3. The method of claim 2 further comprising laterally trimming photoresist of the second set of photoresist features prior to forming the spacer material.

4. The method of claim 1 wherein the first and second sets of masking features are first and second sets of photoresist features, respectively, and further comprising laterally trimming photoresist of the first and second sets of photoresist features in a common process step prior to forming the spacer material.

5. The method of claim 1 wherein the substrate is a semiconductor substrate.

6. A method of forming a pattern, comprising:

photolithographically forming a first set of photoresist features over the substrate;

photolithographically forming a second set of photoresist features, at least some of the features of said second set alternating with photoresist features of the first set along at least one cross-section extending through photoresist features of the first and second sets;

forming spacer material over and between the photoresist features of the first and second sets;

anisotropically etching the spacer material to form spacers along the photoresist features of the first and second sets; and

removing the photoresist features of the first and second sets to leave a pattern of the spacers over the substrate.

7. The method of claim 6 further comprising laterally trimming photoresist of the first set of photoresist features to narrow the photoresist features of the first set prior to forming the second set of photoresist features.

8. The method of claim 7 wherein the lateral trimming photoresist of the first set of photoresist features narrows the photoresist features of the first set by from about two-thirds to about three-quarters.

9. The method of claim 7 further comprising laterally trimming photoresist of the second set of photoresist features to narrow the photoresist features of the second set prior to forming the spacer material.

10. The method of claim 9 wherein the lateral trimming photoresist of the second set of photoresist features narrows the photoresist features of the second set by from about two-thirds to about three-quarters.

11. The method of claim 7 further comprising:

treating the narrowed photoresist features of the first set to render such narrowed photoresist features resistant to subsequent trimming,

after said treating, laterally trimming the second set of photoresist features to narrow said photoresist features prior to forming the spacer material.

12. The method of claim 11 wherein the treating comprises thermal treatment of the narrowed photoresist features of the first set to chemically alter at least exposed surfaces of the narrowed photoresist features of the first set.

13. The method of claim 11 wherein the treating comprises atomic layer deposition of a silicon-dioxide-containing material along exposed surfaces of the narrowed photoresist features of the first set.

14. The method of claim 6 further comprising laterally trimming photoresist of the first and second sets of photoresist features in a common process step prior to forming the spacer material.

15. A method of forming a pattern, comprising:

photolithographically forming a first set of photoresist features over the substrate;

the first set of photoresist features being spaced from one another by first gaps;

the photoresist features of the first set being at a first pitch, with said first pitch being a distance across a first photoresist feature and a first gap;

photolithographically forming a second set of photoresist features, at least some of the features of said second set being within the first gaps so that photoresist features of the second set alternate with photoresist features of the first set along at least one cross-section extending through photoresist features of the first and second sets;

the second set of photoresist features being spaced from one another by second gaps;

the photoresist features of the second set being at a second pitch, with said second pitch being a distance across a second photoresist feature and a second gap;

the second pitch being about the same as the first pitch;

forming spacer material over and between the photoresist features of the first and second sets;

anisotropically etching the spacer material to form spacers along the photoresist features of the first and second sets; and

removing the photoresist features of the first and second sets to leave a pattern of the spacers over the substrate.

16. The method of claim 15 wherein photoresist features of the first set of photoresist features comprise about three-eighths of the first pitch.

17. The method of claim 15 further comprising laterally trimming photoresist of the first and second sets of photoresist features prior to forming the spacer material.

18. The method of claim 17 wherein the laterally trimming of the photoresist of the first and second sets of photoresist features occurs in a single process step.

19. The method of claim 17 wherein the laterally trimming of the photoresist of the first set of photoresist features occurs in a separate process step from the lateral trimming of the photoresist of the second set of photoresist features.

20. A method of forming a pattern, comprising:

photolithographically forming a first set of photoresist features over the substrate;

individual features of the first set of photoresist features having widths of from about 3×

to about 4× and

being spaced from one another by first gaps;

the first gaps having widths of from about 4×

to about 5×

;

laterally trimming the individual features of the first set of photoresist features to form trimmed first photoresist features;

the trimmed first photoresist features having widths of about x;

the trimming of the first photoresist features extending the widths of the first gaps to about 7×

;

treating the trimmed first photoresist features to render the trimmed first photoresist features resistant to subsequent lateral trimming and/or solvent casting;

after treating the trimmed first photoresist features, photolithographically forming a second set of photoresist features over the substrate, at least some of the features of said second set being within the extended first gaps so that photoresist features of the second set alternate with photoresist features of the first set along at least one cross-section extending through photoresist features of the first and second sets;

individual features of the second set of photoresist features having widths of from about 3×

to about 4× and

being spaced from the trimmed first photoresist features by intervening gaps having widths of from about x to about 2×

;

laterally trimming the individual features of the second set of photoresist features to form trimmed second photoresist features;

the trimmed second photoresist features having widths of about x;

the trimming of the second photoresist features extending the widths of the intervening gaps to from about 3×

to about 4×

;

forming spacer material over and between the trimmed first and second photoresist features;

anisotropically etching the spacer material to form spacers along the trimmed first and second photoresist features, the spacers having widths of about x; and

removing the trimmed first and second photoresist features to leave a pattern of the spacers over the substrate, the pattern comprising spacers of width x spaced from one another by distances of width x.

21. The method of claim 20 wherein the treating of the trimmed first photoresist features comprises forming a protective material along surfaces the trimmed first photoresist features.

22. The method of claim 21 wherein the forming of the protective material comprises atomic layer deposition.

23. The method of claim 21 wherein the protective material extends along the substrate within the first gaps, and wherein the photoresist features of the second set are formed over the protective material.

24. The method of claim 20 wherein the treating of the trimmed first photoresist features comprises thermal treatment of the trimmed first photoresist features to induce a chemical change throughout the trimmed first photoresist features.

25. The method of claim 20 wherein the treating of the trimmed first photoresist features comprises chemical treatment of outer surfaces of the trimmed first photoresist features to induce a chemical change along the outer surfaces of the trimmed first photoresist features.

26. The method of claim 20 wherein the substrate is a semiconductor substrate, and wherein the spacers consist of silicon dioxide.

27. A method of forming a pattern, comprising:

photolithographically forming a first set of photoresist features over the substrate;

individual features of the first set of photoresist features having widths of about 3× and

being spaced from one another by first gaps;

the first gaps having widths of about 5×

;

photolithographically forming a second set of photoresist features over the substrate, at least some of the features of said second set being within the first gaps so that photoresist features of the second set alternate with photoresist features of the first set along at least one cross-section extending through photoresist features of the first and second sets;

individual features of the second set of photoresist features having widths of about 3× and

being spaced from the first photoresist features by intervening gaps having widths of about x;

laterally trimming the individual features of the first and second sets of photoresist features to form trimmed first and second photoresist features;

the trimmed first and second photoresist features having widths of about x;

the trimming of the first and second photoresist features extending the widths of the intervening gaps to about 3×

;

forming spacer material over and between the trimmed first and second photoresist features;

anisotropically etching the spacer material to form spacers along the trimmed first and second photoresist features, the spacers having widths of about x; and

removing the trimmed first and second photoresist features to leave a pattern of the spacers over the substrate, the pattern comprising spacers of width x spaced from one another by distances of width x.

28. The method of claim 27 further comprising transferring the pattern of the spacers into the substrate with one or more etches.

29. The method of claim 28 wherein the substrate is a semiconductor substrate comprising one or more materials utilized for fabrication of memory architecture, and wherein the transferring the pattern into the substrate patterns said one or more materials into structures of memory architecture.

30. The method of claim 29 wherein the memory architecture is NAND.

31. The method of claim 29 wherein the memory architecture is DRAM.

32. The method of claim 29 wherein the memory architecture comprises cross-point memory cells.

33. The method of claim 28 wherein the spacers consist of silicon dioxide.