Method of forming self-aligned double pattern

Abstract

Mask patterns used for forming patterns or trenches may include first mask patterns, which may be formed by a typical photolithography process, and second mask patterns, which may be formed in a self-aligned manner between adjacent first mask patterns. A sacrificial layer may be deposited and planarized such that the tops of the first mask patterns and the second mask patterns have planar surfaces. After the planarization of the sacrificial layer, the remaining the sacrificial layer may be removed by an ashing process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects of example embodiments will be apparent from the more detailed description and the accompanying drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of example embodiments.

FIGS. 1A through 1H are cross-sectional views illustrating a method of forming a self-aligned double pattern according to an example embodiment of the present invention.

FIGS. 2A through 2H are cross-sectional views illustrating a method of forming an isolation trench according to an example embodiment of the present invention.

Claims

1. A method of forming a self-aligned double pattern, comprising: providing a substrate;forming an underlying layer on the substrate;forming a first mask pattern on the underlying layer;forming a first sacrificial layer on the first mask pattern and the underlying layer;forming a second mask pattern on the first sacrificial layer;etching the first sacrificial layer to form a first sacrificial pattern;forming a second sacrificial layer on the first mask pattern, the second mask pattern, and the underlying layer;planarizing the second sacrificial layer such that top surfaces of the first mask pattern and the second mask pattern are planar;removing the second sacrificial layer; andforming an underlying layer pattern by etching the underlying layer using the first mask pattern, the second mask pattern, and the first sacrificial pattern as an etching mask.

2. The method according to claim 1, wherein forming the first mask pattern includes: forming an etch stop layer on the underlying layer;forming a first mask layer on the etch stop layer;forming a photoresist pattern on the first mask layer; andanisotropically etching the first mask layer using the photoresist pattern as an etch mask.

3. The method according to claim 1, wherein forming the second mask pattern includes: forming a second mask layer on the first sacrificial layer, including filling spaces in the first sacrificial layer; andplanarizing the second mask layer.

4. The method according to claim 1, further comprising: prior to forming the underlying layer pattern, removing the second sacrificial layer that remains between the first and second mask patterns after the planarization of the second sacrificial layer.

5. The method according to claim 1, wherein the first mask pattern is formed of a material having the same etch rate as the second mask pattern, and the underlying layer is formed of a material having a different etch rate from the first mask pattern.

6. The method according to claim 1, wherein the first and second mask patterns are formed of the same material, and a material having a different etch selectivity from the first sacrificial layer.

7. The method according to claim 1, wherein the second sacrificial layer is an organic sacrificial layer selected from the group consisting of a Novolak-based I-line photoresist, a PHS (poly hydroxystyrene)-based KrF photoresist, an Acrylate-based ArF photoresist, and a methacrylate-based ArF photoresist.

8. The method according to claim 1, wherein the second sacrificial layer is anti-reflection coating (ARC) layer or an amorphous carbon layer.

9. A method of forming a self-aligned double pattern, comprising: providing a substrate;forming a first mask pattern on the substrate;forming a first sacrificial layer on the first mask pattern and the substrate;forming a second mask pattern on the first sacrificial layer;etching the first sacrificial layer to form a first sacrificial pattern;forming a second sacrificial layer on the first mask pattern, the second mask pattern, and the substrate;planarizing the second sacrificial layer such that top surfaces of the first mask pattern and the second mask pattern are planar;removing the second sacrificial layer; andforming a trench by an etching process using the first mask pattern and the second mask pattern as an etching mask.

10. The method according to claim 9, wherein forming the first mask pattern comprises: forming an etch stop layer on the substrate;forming a first mask layer on the etch stop layer;forming a photoresist pattern on the first mask layer; andanisotropically etching the first mask layer using the photoresist pattern as an etch mask.

11. The method according to claim 9, wherein forming the second mask pattern includes: forming a second mask layer on the first sacrificial layer, including filling spaces in the first sacrificial layer; andplanarizing the second mask layer.

12. The method according to claim 9, further comprising: prior to forming the trench, removing the second sacrificial layer that remains between the first and second mask patterns after the planarization of the second sacrificial layer.

13. The method according to claim 9, wherein the first and second mask patterns are formed of polycrystalline silicon, and the first sacrificial layer is formed of oxide.

14. The method according to claim 9, wherein the first and second mask patterns are formed of oxide, and the first sacrificial layer is formed of polycrystalline silicon.

15. The method according to claim 10, further comprising: forming a sacrificial oxide layer on the etch stop layer.

16. The method according to claim 15, wherein the sacrificial oxide layer remains after the first mask layer is anisotropically etched.

17. The method according to claim 9, wherein the second sacrificial layer is an organic sacrificial layer selected from the group consisting of a Novolak-based I-line photoresist, a PHS (poly hydroxystyrene)-based KrF photoresist, an Acrylate-based ArF photoresist, and a methacrylate-based ArF photoresist.

18. The method according to claim 9, wherein the second sacrificial layer is anti-reflection coating (ARC) layer or an amorphous carbon layer.

19. The method according to claim 9, wherein planarizing the second sacrificial layer includes an etch back process or a chemical mechanical polishing process.