Mask and method to pattern chromeless phase lithography contact hole

• US 20060147813A1
• Filed: 01/03/2005
• Published: 07/06/2006
• Est. Priority Date: 01/03/2005
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Globalfoundries Singapore Pte Limited (GlobalFoundries, Inc.)
• Inventors: Tan, Sya Kim, Lin, Qun Ying, Tan, Soon Yoeng, Hsia, Liang Choo, Chong, Hury Ming
• Granted Patent: US 7,655,388 B2
• Time in Patent Office: Days
• US Class Current: 430/5
• CPC Class Codes: G03F 1/34 Phase-edge PSM, e.g. chromeless PSM; Preparation thereof

Abstract

A chromeless phase shift mask and Method for making and using. The A chromeless phase shift mask is used to pattern contact holes. The chromeless phase shift mask preferably comprises: a first phase shift region and a second phase shfit region; the first region is comprised of a unit cell which is comprised of a rectangular center section and at least three rectangular sections (legs) outwards extending from the rectangular center section. The second region is adjacent to said first region. The interference between the first and second phase shift regions creates a contact hole pattern.

Claims

1. A phase shift mask comprising:

a mask comprised of a first phase shift region and a second phase shift region;

said first phase shift region and said second phase shift region are about 180 degrees out of phase;

said first phase shift region is comprised of at least a unit cell;

said unit cell is comprised of (a) a center section and (b) at least three rectangular sections extending outwards from said center section;

said center section has a rectangular shape;

said second phase shift region is adjacent to said first region;

the unit cell has a shape that when light passes through said mask, the destructive interference between said first phase shift region and a second phase shift region creates a contact hole pattern.

2. The phase shift mask of claim 1 wherein the center section is centered in the area where a via hole pattern is desired to be formed.

3. The phase shift mask of claim 1 wherein said first phase shift region has an orthogonal cross shape with said center section and four rectangular sections outwards extending from the center section.

4. The phase shift mask of claim 1 wherein said unit cell has an orthogonal cross shape with a square shaped center section and four rectangular sections outwardly orthogonally extending from the square center section.

5. The phase shift mask of claim 1 wherein said unit cell has an orthogonal cross shape with a square shaped center section and four square shaped rectangular sections outwards extending from the square center section;

the center section and the rectangular sections have the same length sides.

6. The phase shift mask of claim 1 wherein said phase shift mask is a chromeless phase shift mask.

7. The phase shift mask of claim 1 wherein said rectangular sections have a minimum length between 70 and 200% of the width of the center section.

8. The phase shift mask of claim 1 which further comprises a plurality of first regions arranged in a row and column formation whereby contact hole are formed in rows or column under the center sections.

9. The phase shift mask of claim 1 which further comprises a plurality of first regions arranged in a row and column formation whereby contact hole are formed in rows or column under the center sections.

10. The phase shift mask of claim 1 wherein said first phase shift region has a 180 degree shift and a second phase shift region has a zero degree shift.

11. The phase shift mask of claim 1 wherein said first phase shift region has a 0 degree shift and a second phase shift region has a 180 degree shift.

12. The phase shift mask of claim 1 wherein mask is thinner in said first phase shift region than in said second phase shift region.

13. The phase shift mask of claim 1 wherein said mask is comprised of a first area for defining contact holes and a second area for defining lines;

said first phase shift regions and said second phase shift regions are in said first area;

said second area does contain said unit cells.

14. The phase shift mask of claim 1 wherein over 90% of the area of the mask is comprised of said first phase shift regions and said second phase shift regions for forming contact hole patterns.

15. The phase shift mask of claim 1 which further includes a regulator feature having the same phase shift as the first region;

said regulator features positioned to create destructive interference in the background region.

16. The phase shift mask of claim 1 which further includes a regulator feature having about the same phase shift as the first phase shift region;

the regulator feature is positioned so that the edge of first phase shift region will interfere with the nearest edge of the regulator feature;

the regulator feature has a width between 1 to 2 times the width of the said center section;

the regulator feature is positioned with a spacing of at least 0.5 times the width of the center section.

17. The phase shift mask of claim 1 wherein shows at least two columns comprised of unit cells;

the two columns are spaced apart;

at least a regulator feature between the two columns.

18. The phase shift mask of claim 1 wherein at least two columns comprised of unit cells;

the two columns are spaced apart and mis-aligned in an x or y direction;

at least a regulator feature between the two columns.

19. The phase shift mask of claim 1 which includes said first region comprised of a double cell comprised of at least two unit cells are joined and at least a first separate unit cell;

the double cell and the first unit cell are separated by at least a regulator feature.

20. A chromeless phase shift mask comprising:

a mask comprised of a first phase shift region and a second phase shift region;

said first phase shift region and said second phase shift region are about 180 degrees out of phase;

said first phase shift region is comprised of at least a unit cell;

said unit cell is comprised of (1) an center section and (2) at least three rectangular sections extending outwards from said center section;

said center section and said rectangular sections have a square shape;

said second phase shift region is adjacent to said first phase shift region;

whereby when light passes through said mask, the destructive interference between said first phase shift region and a second phase shift region creates a contact hole pattern.

21. The chromeless phase shift mask of claim 20 wherein the center section is centered in the area where a via hole pattern is desired to be formed.

22. The chromeless phase shift mask of claim 20 wherein said unit cell has an orthogonal cross shape with a square shaped center section and four square shaped rectangular sections outwards extending from the square center section;

the center section and the rectangular sections have about the same length sides.

23. The chromeless phase shift mask of claim 20 which further comprises a plurality of unit cells arranged in a row and column formation whereby contact holes are formed in rows or column under the center sections.

24. A chromeless phase shift mask comprising:

a mask comprised of a first phase shift region and a second phase shift region;

said first phase shift region and said second phase shift region are about 180 degrees out of phase;

said first phase shift region is comprised of unit cells, each unit cell comprised of (1) an center section and (2) four rectangular sections extending outwards from said center section;

said center section has a rectangular shape;

said unit cells are connected by adjacent rectangular sections to form a plurality of rows and columns;

said second phase shift region is adjacent to said first region;

whereby when light passes through said mask, the destructive interference between said first phase shift region and a second phase shift region creates a contact hole pattern.

25. The chromeless phase shift mask of claim 24 wherein said unit cell has an orthogonal cross shape with a square shaped center section and four square shaped rectangular sections outwards extending from the square center section;

the center section and the rectangular sections have the same length sides.

26. The chromeless phase shift mask of claim 24 wherein over 90% of the area of the mask is comprised of said first phase shift regions and said second phase shift regions for forming contact hole patterns.

27. The chromeless phase shift mask of claim 24 which further includes a regulator feature having the same phase shift as the first region;

said regulator features positioned to create destructive interference in the background region.

28. The chromeless phase shift mask of claim 24 which further includes a regulator feature having about the same phase shift as the first phase shift region;

the regulator feature is positioned so that the edge of first phase shift region will interfere with the nearest edge of the regulator feature;

the regulator feature has a width between 1 to 2 times the width of the said center section;

the regulator feature is positioned with a spacing of at least 0.5 times the width of the center section.

29. A method for projecting patterns onto a semiconductor substrate comprising:

providing an illumination source;

providing a phase shift mask that has a first phase shift region and a second phase shift region;

said first phase shift region and said second phase shift region are about 180 degree out of phase;

said first region comprised of a unit cell;

said unit cell comprised of (a) a center section and (b) at least three rectangular sections extending outwards from said center section;

said center section has a rectangular shape;

the unit cell has a shape that when light passes through said mask, the destructive interference between said first phase shift region and a second phase shift region creates a contact hole pattern;

projecting light from said illumination source thru said phase shift mask onto a semiconductor substrate.

30. The method of claim 29 wherein the dimension width of the rectangular sections are less than half the illuminating wavelength and low inner and outer sigma factors are used.

31. A method for projecting patterns onto a semiconductor substrate comprising:

providing an illumination source;

providing a phase shift mask that has a first phase shift region and a second phase shift region;

said first phase shift region and said second phase shift region are about 180 degree out of phase;

said first region comprised of a unit cell;

said unit cell comprised of (a) a center section and (b) at least three rectangular sections extending outwards from said center section;

said center section has a rectangular shape;

the unit cell has a shape that when light passes through said mask, the destructive interference between said first phase shift region and a second phase shift region creates a contact hole pattern;

providing a lens system that receives the pattern that is projected from the phase shift mask;

reducing the pattern in the lens system; and

projecting the reduced pattern onto a semiconductor substrate.

32. The method of claim 31 wherein said illumination source is an off-axis type illumination source.

33. The method of claim 31 wherein said illumination source is a quasar type illumination source.

34. The method of claim 31 wherein the reduced pattern is projected onto a photosensitive layer over a semiconductor substrate.

35. The method of claim 31 wherein said semiconductor substrate comprises a photoresist layer and said reduced pattern forms a contact hole pattern on said photoresist layer.

36. The method of claim 31 wherein said semiconductor substrate comprises a photoresist layer and said reduced pattern forms a row or a column of contact hole patterns on said photoresist layer.

37. The method of claim 31 wherein said first phase shift region has a 180 degree shift and a second phase shift region has a zero degree shift.

38. The method of claim 31 wherein said first phase shift region has a 0 degree shift and a second phase shift region has a 180 degree shift.

39. The method of claim 31 wherein said first phase shift region has an orthogonal cross shape with said center section and four rectangular sections outwards extending from the center section.

40. The method of claim 31 wherein said unit cell has an orthogonal cross shape with a center section and four rectangular sections outwards extending from the rectangular center section.

41. The method of claim 31 wherein said unit cell has an orthogonal cross shape with a square shaped center section and four square shaped rectangular sections outwards extending from the square center section;

the center section and the rectangular sections have the same length sides.

42. The method of claim 31 wherein said phase shift mask is a chromeless phase shift mask.

43. The method of claim 31 wherein said rectangular sections have a minimum length between 70 and 200% of the width of the center section.

44. The method of claim 31 wherein said first region comprises a plurality of unit cells arranged in a row and column formation whereby contact holes are formed in rows or column under the center sections.

45. The method of claim 31 wherein further comprises a plurality of first regions arranged in a row and column formation whereby contact holes are formed in rows and column under the center sections.

46. A method for forming a phase shift mask for use in semiconductor device fabrication;

comprising;

providing a mask;

forming masking layer over said mask;

said masking layer has a pattern which can be used to etch said mask to form at least a first phase shift region and a second phase shift region which provides a phase shift for light passing there through;

said first phase shift region having a cross shape;

etch said mask through said masking layer to form said first phase shift region and said second phase shift region;

said first phase shift region is comprised of at least a unit cell;

said unit cell is comprised of (a) a center section and (b) at least three rectangular sections extending outwards from said center section;

said center section has a rectangular shape;

the unit cell has a shape that when light passes through said mask, the destructive interference between said first phase shift region and a second phase shift region creates a contact hole pattern.

47. The method of claim 46 wherein said first region is a 0 degree phase shift region and said second region is a 180 degree phase shift region.

48. The method of claim 46 wherein said first phase shift region is a 180 degree phase shift region and said second region is a 0 degree phase shift region.

49. The method of claim 46 wherein the etch forms a trench in said first phase shift region;

said first phase shift region is a 180 degree phase shift region and said second region is a 0 degree phase shift region.

50. The method of claim 46 wherein the etch forms a trench in said second phase shift region;

said first region is a 0 degree phase shift region and said second region is a 180 degree phase shift region.

51. The method of claim 46 wherein said masking layer is comprised of two or more layers;

said masking layer is comprised of a chrome layer and an overlying resist layer.

52. The method of claim 46 wherein said mask is comprised of quartz, silica glass and borosilicate glass.

53. The method of claim 46 wherein said mask which further includes a regulator feature having about the same phase shift as the first phase shift region;

the regulator feature is positioned so that the edge of first phase shift region will interfere with the nearest edge of the regulator feature;

the regulator feature has a width between 1 to 2 times the width of the said center section;

the regulator feature is positioned with a spacing of at least 0.5 times the width of the center section.

54. The method of claim 46 wherein said mask has at least two columns comprised of unit cells;

the two columns are spaced apart;

at least a regulator feature between the two columns.

55. The method of claim 46 wherein said mask has at least two columns comprised of unit cells;

the two columns are spaced apart and mis-aligned in an x or y direction;

at least a regulator feature between the two columns.

56. The method of claim 46 wherein said first region comprised of a double cell comprised of at least two unit cells are joined and at least a first separate unit cell;

the double cell and the first unit cell are separated by at least a regulator feature.