Method for forming a hard mask in a layer on a planar device
First Claim
1. A method for forming a hard mask in a first layer on a planar device, which comprises the steps of:
- depositing a second layer on the first layer;
using a lithographic projection process for forming at least one elevated first structure from the second layer disposed above the first layer;
conformally depositing a third layer on the elevated first structure and on the first layer;
etching back the third layer for forming a first spacer structure and a second spacer structure each disposed on a respective side area of the elevated first structure; and
etching the second layer selectively with respect to the first and third layers to remove the elevated first structure disposed between the first and second spacer structures, resulting in the hard mask being formed from the first and second spacer structures.
5 Assignments
0 Petitions
Accused Products
Abstract
A hard mask is produced from spacer structures. The spacer structures are formed from a conformal deposition on elevated structures produced lithographically in a projection process. The conformal deposition is etched back laterally on the elevated structures resulting in the spacer structures. The elevated structures between the spacer structures are subsequently etched away, so that the spacer structures remain in an isolated fashion as sublithographic structures of a hard mask with a doubled structure density compared with that originally produced in lithographic projection. In a regularly disposed two-dimensional array of structures in the hard mask for forming trenches—for instance for trench capacitors—the method achieves a doubling of the structure density in the array. A further iteration step is formed by forming further spacer structures on the first and second spacer structures, thereby achieving an even higher increase in structure density in the hard mask. REL/rit
-
Citations
27 Claims
-
1. A method for forming a hard mask in a first layer on a planar device, which comprises the steps of:
-
depositing a second layer on the first layer;
using a lithographic projection process for forming at least one elevated first structure from the second layer disposed above the first layer;
conformally depositing a third layer on the elevated first structure and on the first layer;
etching back the third layer for forming a first spacer structure and a second spacer structure each disposed on a respective side area of the elevated first structure; and
etching the second layer selectively with respect to the first and third layers to remove the elevated first structure disposed between the first and second spacer structures, resulting in the hard mask being formed from the first and second spacer structures. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A method for forming a hard mask in a first layer on a planar device, which comprises the steps of:
-
depositing a fourth layer on the first layer;
using a lithographic projection process for forming a hole structure in the fourth layer;
conformally depositing a third layer;
etching back the third layer for forming a first spacer structure and a second spacer structure on a respective side area of the hole structure;
depositing and filling the hole structure with a second layer;
planarizing the second layer;
etching the fourth layer selectively with respect to the first, second and third layers for forming an elevated first structure enclosed by the first and second spacer structures on the side areas; and
etching the second layer selectively with respect to the first and third layers for removing the elevated first structure between the first and second spacer structures, resulting in the hard mask being formed from the spacer structures. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
-
Specification