Pattern forming method

Abstract

A pattern forming method including: (a) forming a porous layer above an etching target layer; (b) forming an organic material with a transferred pattern on the porous layer; (c) forming, by use of the transferred pattern, a processed pattern in a transfer oxide film that is more resistant to etching than the porous layer; and (d) transferring the processed pattern to the etching target layer by use of the transfer oxide film as a mask.

What is claimed is: 
     
       1. A pattern forming method comprising:
 (a) forming a porous layer above an etching target layer; 
 (b) forming an organic material with a transferred pattern on the porous layer; 
 (c) forming, by use of the transferred pattern, a processed pattern in a transfer oxide film that is more resistant to etching than the porous layer, wherein the (c) forming includes:
 (c1) forming the transferred pattern in the porous layer, and 
 (c2) forming, in the transfer oxide film, the processed pattern that is the same as the transferred pattern; and 
 
 (d) transferring the processed pattern to the etching target layer by use of the transfer oxide film as a mask, wherein the (a) forming includes:
 (a1) forming the transfer oxide film on the etching target layer, and 
 (a2) forming the porous layer on the transfer oxide film. 
 
 
     
     
       2. The pattern forming method according to  claim 1 , wherein the (c) forming includes:
 (c3) forming the transfer oxide film on the porous layer;   (c4) etching back the transfer oxide film until a top surface of the porous layer is exposed; and   (c5) removing the porous layer,   wherein the forming the transferred pattern in the porous layer is by use of the organic material as a mask.   
     
     
       3. The pattern forming method according to  claim 1 , wherein, at the (c1) forming, the transferred pattern is formed in the porous layer using, as a mask, the organic material reduced down by etching sidewall portions of the organic material laterally inward. 
     
     
       4. The pattern forming method according to  claim 3 , wherein the sidewall portions of the organic material are etched laterally inward by an isotropic etching technique. 
     
     
       5. The pattern forming method according to  claim 4 , wherein, at the (c1) forming, the transferred pattern is formed in the porous layer by dry-etching the porous layer with a CF-based gas. 
     
     
       6. The pattern forming method according to claim  2  1, wherein the porous layer is made of an oxide film having a lower density than an oxide film formed by an LPCVD method. 
     
     
       7. The pattern forming method according to  claim 3 , wherein the porous layer is made of an oxide film having a lower density than an oxide film formed by an LPCVD method. 
     
     
       8. The pattern forming method according to  claim 5 , wherein the porous layer is made of an oxide film having a lower density than an oxide film formed by an LPCVD method. 
     
     
       9. The pattern forming method according to  claim 1 , wherein the porous layer has a density of 1.8 g/cm 3  or lower. 
     
     
       10. The pattern forming method according to claim  2  1, wherein the porous layer has a density of 1.8 g/cm 3  or lower. 
     
     
       11. The pattern forming method according to  claim 3 , wherein the porous layer has a density of 1.8 g/cm 3  or lower. 
     
     
       12. The pattern forming method according to  claim 5 , wherein the porous layer has a density of 1.8 g/cm 3  or lower. 
     
     
       13. A pattern forming method comprising:
 (a) forming a porous layer above an etching target layer; wherein the (a) forming includes:
 (a1) forming a transfer film on the etching target layer, and 
 (a2) forming the porous layer above the transfer film; 
   (b) forming an organic material with a first transferred pattern by transferring a pattern formed on a template into the organic material;   (c) forming, based on the first transferred pattern, a processed pattern in the transfer film, wherein the (c) forming includes:
 (c1) forming a second transferred pattern in the porous layer based on the first transferred pattern, and 
 (c2) forming, in the transfer film, the processed pattern based on the second transferred pattern; and 
   (d) transferring the processed pattern to the etching target layer using the transfer film as a mask.   
     
     
       14. The pattern forming method according to claim 13, wherein the porous layer is made of a silicon oxide film. 
     
     
       15. The pattern forming method according to claim 14, wherein the porous layer is a laminate film. 
     
     
       16. The pattern forming method according to claim 13, wherein the porous layer is formed by a coating process. 
     
     
       17. The pattern forming method according to claim 14, wherein the porous layer is formed by a coating process. 
     
     
       18. The pattern forming method according to claim 15, wherein the porous layer is formed by a coating process. 
     
     
       19. The pattern forming method according to claim 13, wherein the porous layer has a lower density than an oxide film formed by an LPCVD method. 
     
     
       20. The pattern forming method according to claim 14, wherein the porous layer has a lower density than an oxide film formed by an LPCVD method. 
     
     
       21. The pattern forming method according to claim 16, wherein the porous layer has a lower density than an oxide film formed by an LPCVD method. 
     
     
       22. The pattern forming method according to claim 17, wherein the porous layer has a lower density than an oxide film formed by an LPCVD method. 
     
     
       23. The pattern forming method according to claim 13, wherein the transfer film includes a carbon film. 
     
     
       24. The pattern forming method according to claim 14, wherein the transfer film includes a carbon film. 
     
     
       25. The pattern forming method according to claim 16, wherein the transfer film includes a carbon film. 
     
     
       26. The pattern forming method according to claim 17, wherein the transfer film includes a carbon film. 
     
     
       27. The pattern forming method according to claim 23, wherein the carbon film is processed using the porous layer having the second transferred pattern as a mask. 
     
     
       28. The pattern forming method according to claim 24, wherein the carbon film is processed using the porous layer having the second transferred pattern as a mask. 
     
     
       29. The pattern forming method according to claim 25, wherein the carbon film is processed using the porous layer having the second transferred pattern as a mask. 
     
     
       30. The pattern forming method according to claim 26, wherein the carbon film is processed using the porous layer having the second transferred pattern as a mask. 
     
     
       31. The pattern forming method according to claim film 23, wherein the processed pattern is transferred to the etching target layer using the carbon film as a mask. 
     
     
       32. The pattern forming method according to claim film 24, wherein the processed pattern is transferred to the etching target layer using the carbon film as a mask. 
     
     
       33. The pattern forming method according to claim film 25, wherein the processed pattern is transferred to the etching target layer using the carbon film as a mask. 
     
     
       34. The pattern forming method according to claim film 26, wherein the processed pattern is transferred to the etching target layer using the carbon film as a mask. 
     
     
       35. The pattern forming method according to claim 13, wherein the etching target layer includes silicon. 
     
     
       36. The pattern forming method according to claim 14, wherein the etching target layer includes silicon. 
     
     
       37. The pattern forming method according to claim 16, wherein the etching target layer includes silicon. 
     
     
       38. The pattern forming method according to claim 23, wherein the etching target layer includes silicon. 
     
     
       39. The pattern forming method according to claim 27, wherein the etching target layer includes silicon. 
     
     
       40. The pattern forming method according to claim 31, wherein the etching target layer includes silicon. 
     
     
       41. A pattern forming method comprising:
 forming a transfer film on an etching target layer;   forming a first layer above the transfer film, wherein the first layer has a lower density than at least one of: the transfer film or a film formed by a low-pressure chemical vapor deposition (LPCVD) process;   forming an organic material with a first transferred pattern by transferring a pattern formed on a template into the organic material;   forming a second transferred pattern in the first layer based on the first transferred pattern;   forming, in the transfer film, a processed pattern based on the second transferred pattern; and   transferring the processed pattern to the etching target layer using the transfer film as a mask.   
     
     
       42. The pattern forming method according to claim 41, wherein the first layer has the lower density than the transfer film. 
     
     
       43. The pattern forming method according to claim 41, wherein the first layer is made of a silicon oxide film. 
     
     
       44. The pattern forming method according to claim 41, wherein the first layer is formed by a coating process. 
     
     
       45. The pattern forming method according to claim 42, wherein the first layer is formed by a coating process. 
     
     
       46. The pattern forming method according to claim 41, wherein the transfer film includes a carbon film. 
     
     
       47. The pattern forming method according to claim 42, wherein the transfer film includes a carbon film. 
     
     
       48. The pattern forming method according to claim 45, wherein the transfer film includes a carbon film. 
     
     
       49. The pattern forming method according to claim 41, wherein the etching target layer includes silicon. 
     
     
       50. The pattern forming method according to claim 42, wherein the etching target layer includes silicon. 
     
     
       51. The pattern forming method according to claim 46, wherein the etching target layer includes silicon. 
     
     
       52. A pattern forming method comprising:
 (a) forming a first layer above an etching target layer; wherein the (a) forming includes:
 (a1) forming a transfer film on the etching target layer, and 
 (a2) forming the first layer above the transfer film, the first layer having a lower density than at least one of: the transfer film or a film formed by a low-pressure chemical vapor deposition (LPCVD) process; 
   (b) forming an organic material with a first transferred pattern by transferring a pattern formed on a template into the organic material;   (c) forming, based on the first transferred pattern, a processed pattern in the transfer film, wherein the (c) forming includes:
 (c1) forming a second transferred pattern in the first layer based on the first transferred pattern, and 
 (c2) forming, in the transfer film, the processed pattern based on the second transferred pattern; and 
   (d) transferring the processed pattern to the etching target layer using the transfer film as a mask.   
     
     
       53. The pattern forming method according to claim 52, wherein the first layer has the lower density than the transfer film. 
     
     
       54. The pattern forming method according to claim 52, wherein the transfer film includes a carbon film. 
     
     
       55. The pattern forming method according to claim 53, wherein the transfer film includes a carbon film. 
     
     
       56. The pattern forming method according to claim 52, wherein the etching target layer includes silicon. 
     
     
       57. The pattern forming method according to claim 52, wherein the film formed by the CVD process includes silicon. 
     
     
       58. The pattern forming method according to claim 52, wherein the first layer has a density of 1.8 g/cm3 or lower. 
     
     
       59. The pattern forming method according to claim 52, wherein the first layer is formed by a coating process. 
     
     
       60. The pattern forming method according to claim 59, wherein the first layer is formed by the coating process at temperature of 300° C. to 350° C. 
     
     
       61. The pattern forming method according to claim 41, wherein the first layer has a density of 1.8 g/cm3 or lower. 
     
     
       62. The pattern forming method according to claim 54, wherein the carbon film is processed using the first layer having the second transferred pattern as a mask. 
     
     
       63. The pattern forming method according to claim 42, wherein the first layer has a density of 1.8 g/cm3 or lower. 
     
     
       64. The pattern forming method according to claim 53, wherein the first layer has a density of 1.8 g/cm3 or lower.