Fabrication method of sub-resolution pitch for integrated circuits

• US 6,867,116 B1
• Filed: 11/10/2003
• Issued: 03/15/2005
• Est. Priority Date: 11/10/2003
• Status: Active Grant

• Current Assignee: Macronix International Co., Ltd.
• Original Assignee: Macronix International Co., Ltd.
• Inventors: Chung, Henry
• Primary Examiner(s): Zarabian, Amir
• Assistant Examiner(s): Tran, Thanh Y.
• Application Number:
  US10/703,453
• Time in Patent Office: 491 Days
• Field of Search: 438/551, 438758-761, 438/734, 438/735, 438/736, 438/737, 438/738, 438/584, 438/585, 438/778
• US Class Current: 438/551
• 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: H01L 21/28123 Lithography-related aspects, e.g. sub-lithography lengths; Isolation-related aspects, e.g. to solve problems arising at the crossing with the side of the device isolation; Planarisation aspects
• CPC Class Codes: H01L 21/32139 using masks

Abstract

A method of manufacturing a semiconductor device using a scanner, wherein the scanner is capable of realizing a minimum pitch, wherein the minimum pitch is the smallest possible pitch for the scanner, the method including providing a semiconductor substrate, forming a first layer over the semiconductor substrate, forming a second layer over the first layer, patterning the second layer to form a plurality of second layer patterns, patterning the first layer to form a plurality of first layer patterns, performing a tone reversal to form a reversed tone for the second layer patterns, and etching the first layer patterns using the reversed tone as a mask, wherein the etched first layer patterns have a final pitch size, and wherein the final pitch is smaller than the minimum pitch.

Claims

1. A method of manufacturing a semiconductor device using a scanner, wherein the scanner is capable of realizing a minimum pitch, wherein the minimum pitch is the smallest possible pitch for the scanner, the method comprising:

providing a semiconductor substrate;

forming a first layer over the semiconductor substrate;

forming a second layer over the first layer;

patterning the second layer to form a plurality of second layer patterns;

patterning the first layer to form a plurality of first layer patterns, wherein a line width of the first layer patterns is greater than a line width of the second layer patterns, and each second layer pattern is located approximately over the center of a corresponding first layer pattern;

performing a tone reversal to form a reversed tone for the second layer patterns; and

etching the first layer patterns using the reversed tone as a mask, wherein the etched first layer patterns have a final pitch size, and wherein the final pitch is smaller than the minimum pitch.

2. The method of claim 1, wherein patterning the second layer comprises

depositing a layer of photoresist over the second layer;

patterning the photoresist to form a plurality of photoresist patterns using the scanner, wherein a line width of the photoresist patterns is approximately equal to half of the minimum pitch;

trimming the photoresist patterns, wherein the trimmed photoresist patterns have a line width substantially smaller than half of the minimum pitch; and

etching the second layer using the trimmed photoresist patterns as mask.

3. The method of claim 2, wherein the photoresist is removed before patterning the first layer.

4. The method of claim 1, wherein patterning the first layer comprises:

depositing a third layer over the second layer patterns and the first layer, wherein the third layer has a structure with a plurality of openings;

etching parts of the third layer at the bottom of the plurality of openings;

etching the first layer using the etched third layer as mask; and

removing the third layer.

5. The method of claim 4, wherein the third layer comprises polymer.

6. The method of claim 4, wherein patterning the second layer comprises depositing and patterning a layer of photoresist, and wherein the photoresist and the third layer are removed together.

7. The method of claim 1, wherein performing the tone reversal for the second layer patterns comprises

forming a layer of oxide over the second layer patterns and the first layer patterns;

polishing the oxide to expose the second layer patterns and to form a plurality of oxide patterns; and

etching the second layer patterns;

wherein the oxide patterns represent the reversed tone of the second layer patterns.

8. The method of claim 7, wherein the first layer patterns are etched using the oxide patterns as mask.

9. The method of claim 1, wherein the line width of the second layer patterns is approximately one fourth of the minimum pitch.

10. The method of claim 1, wherein the line width of the first layer patterns is approximately three fourths of the minimum pitch, and a space between the first layer patterns is approximately one fourth of the minimum pitch.

11. The method of claim 1, wherein the final pitch is approximately half of the minimum pitch.

12. The method of claim 1, wherein the first layer is a gate contact layer.

13. The method of claim 1, further comprising

forming a gate dielectric layer over the substrate;

and

forming a gate contact layer over the gate dielectric;

wherein the first layer is formed over the gate contact layer.

14. The method of claim 13, further comprising

etching the gate contact layer using the etched first layer patterns as a mask;

and

removing the first layer patterns.

15. A method of manufacturing a semiconductor device using a scanner, wherein the scanner is capable of realizing a minimum pitch, wherein the minimum pitch is the smallest possible pitch for the scanner, the method comprising:

providing a first layer;

depositing a layer of photoresist over the first layer;

patterning the photoresist to form a plurality of photoresist patterns, wherein the photoresist patterns have a line width approximately one fourth of the minimum pitch; and

etching a portion of the first layer using the trimmed photoresist patterns as mask, wherein the etched first layer includes a flat layer with a plurality of protrusions thereon, and wherein the protrusions have a line width approximately one fourth of the minimum pitch;

etching the flat layer to form a plurality of flat layer patterns, wherein a line width of the flat layer patterns is approximately three fourths of the minimum pitch, and wherein each protrusion is located approximately on top of the center of a corresponding flat layer pattern;

performing a tone reversal to form a reversed tone for the protrusions; and

etching the flat layer patterns, wherein the etched flat layer patterns have a final pitch size, and wherein the final pitch is approximately equal to a half of the minimum pitch.

16. The method of claim 15, further comprising

providing a gate contact layer, wherein the first layer is provided over the gate contact layer;

and

etching the gate contact layer using the etched flat layer patterns as mask.

17. The method of claim 15, wherein performing the tone reversal for the protrusions comprises

forming a layer of oxide over the protrusions and the flat layer;

polishing the oxide to expose the protrusions and to form a plurality of oxide patterns; and

etching the protrusions;

wherein the oxide patterns represent the reversed tone of the protrusions.

18. A method of manufacturing a semiconductor device using a scanner, wherein the scanner is capable of realizing a minimum pitch, wherein the minimum pitch is the smallest possible pitch for the scanner, the method comprising:

providing a semiconductor substrate;

forming a first layer over the semiconductor substrate;

depositing a layer of photoresist over the first layer;

patterning the photoresist to form a plurality of photoresist patterns using the scanner, wherein a line width of the photoresist patterns is approximately equal to a half of the minimum pitch;

trimming the photoresist patterns, wherein the trimmed photoresist patterns have a line width approximately one fourth of the minimum pitch;

etching a portion of the first layer using the trimmed photoresist patterns as mask, wherein the etched first layer includes a flat layer with a plurality of protrusions thereon, and wherein the protrusions have a line width approximately one fourth of the minimum pitch;

etching the flat layer to form a plurality of flat layer patterns, wherein a line width of the flat layer patterns is approximately three fourths of the minimum pitch, and wherein each protrusion is located approximately on top of the center of a corresponding flat layer pattern;

performing a tone reversal to form a reversed tone for the protrusions; and

etching the flat layer patterns, wherein the etched flat layer patterns have a final pitch size, and wherein the final pitch is approximately equal to a half of the minimum pitch.

19. The method of claim 18, further comprising

forming a gate dielectric layer over the semiconductor substrate;

forming a gate contact layer over the gate dielectric layer, wherein the first layer is formed over the gate contact layer;

etching the gate contact layer using the etched flat layer patterns as a mask; and

removing the first layer patterns.

20. The method of claim 18, wherein etching the flat layer comprises

depositing a layer of polymer over the flat layer and the protrusions, wherein the polymer has a structure with a plurality of openings;

etching the part of the polymer at the bottom of the openings;

etching the flat layer using the etched polymer as a mask; and

removing the polymer.