METHOD OF FORMING PATTERN OF SEMICONDUCTOR DEVICE

Abstract

A method of forming a pattern of a semiconductor device includes forming a hard mask layer over a semiconductor substrate and forming a photoresist film pattern over the hard mask layer. An outer portion of the photoresist film pattern is converted into an oxide layer having a first vertical wall, a second vertical wall, and a horizontal wall, wherein an inner portion of the photoresist film pattern is enclosed within the converted oxide layer. At least a portion of the horizontal wall is removed to expose the photoresist film pattern remaining within the converted oxide layer. The exposed photoresist film pattern is removed to form first and second oxide patterns corresponding to the first and second vertical walls, respectively, of the oxide layer. The hard mask layer is patterned using the first and second oxide patterns as etch masks. The semiconductor substrate is etched using the patterned hard mask layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 7A are cross-sectional views showing a cell region, sequentially shown to illustrate a method of forming a pattern of a semiconductor device according to an embodiment of the present invention; and

FIGS. 1B to 7B are perspective views showing a connection of a peripheral region, sequentially shown to illustrate a method of forming a pattern of a semiconductor device according to an embodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

FIGS. 1A to 7A are cross-sectional views showing a cell region, sequentially shown to illustrate a method of forming a pattern of a semiconductor device according to an embodiment of the present invention. FIGS. 1B to 7B are perspective views showing a connection of a peripheral region, sequentially shown to illustrate a method of forming a pattern of a semiconductor device according to an embodiment of the present invention.

Referring to FIGS. 1A and 1B, hard mask 11 is formed over a semiconductor substrate 10 of a cell region and of a peripheral region, respectively. Photoresist film 12 is formed over the hard mask 11, respectively.

The hard mask 11 may be formed using poly (i.e., methyl methacrylate), polymer, novolacs, sulfone polymer or the like. The photoresist film 12 may be formed using a chemical amplification type sensitizer.

Referring to FIGS. 2A and 2B, photoresist film pattern 12a is formed by performing an etch process using a mask (not shown) on the photoresist film 12 (refer to FIGS. 1A and 1B). The etch process may be performed using KrF, ArF, F2 or EUV light source.

Assuming that the sum of the width A of the photoresist film pattern 12a and the distance B of the photoresist film pattern 12a is the pitch of the photoresist film pattern 12a, the photoresist film pattern 12a is formed in such a manner that the pitch of the photoresist film pattern 12a is twice the pitch that is finally formed. Alternatively, the width A of the photoresist film pattern 12a may be three times the distance B of the photoresist film pattern 12a. However, the present invention is not limited to the above, the width A of the photoresist film pattern 12a and the distance B of the photoresist film pattern 12a may be changed by taking into consideration the final size of the pattern to be formed.

Referring to FIGS. 3A and 3B, a silylation reagent including silicon is coated on the photoresist film pattern 12a (refer to FIGS. 2A and 2B), thus silylating the sides and top surface of the photoresist film pattern 12a. Exposure or baking is performed in separate steps, or exposure and baking are performed simultaneously on the photoresist film pattern 12a whose surfaces have been silylated, thereby changing the sides and top surface of the photoresist film pattern 12a into oxide layer 13. The oxide layer 13 may be SiO₂. Meanwhile, photoresist film 12b, which is the remaining part of the unchanged photoresist film pattern 12a, remain at the center of the oxide layer 13.

The formed thickness of the oxide layer 13 may be changed by adjusting temperature and time of the exposure or baking process. The thickness C of the oxide layer 13 is chosen to have the same thickness as the thickness of the target pattern. Alternatively, the thickness C of the oxide layer 13 may be identical to the distance B of the oxide layer 13.

The silylation reagent may be used as a liquid phase or a gas phase, and may contain 3 to 70% silicon. The silylation reagent may use one of the following; hexamethyl disilazane (HMDS), tetramethyl disilazane (TMDS), bisdimethyl amino methylsilane (BDMAMS), bisdimethyl amino dimethylsilane, dimethylsilyl dimethylamine, dimethylsilyl diethylamine, trimethylsilyl diethylamine or dimethyl amino pentamethylsilane.

Referring to FIGS. 4A and 4B, photoresist 14 is formed over the entire surface of the hard mask 11. Etch hole 15 are formed so that given regions of the oxide layer 13, formed in the semiconductor substrate 10 of the peripheral region, are exposed. Exposure and development processes are performed through the etch hole 15, thus cutting the given regions of the oxide layer 13. Accordingly, connectors of the peripheral region formed in a subsequent process can be separated from each other.

Referring to FIGS. 5A and 5B, the photoresist 14 (refer to FIGS. 4A and 4B) is removed. The top surfaces of the oxide layer 13 (refer to FIGS. 4A and 4B) is removed through anisotropic etch so that the remaining photoresist film 12b (refer to FIGS. 4A and 4B) is exposed. The anisotropic etch may be dry etched. The remaining photoresist film 12b is removed using a well-known technique, thus forming oxide layer pattern 13a. Accordingly, the width of the oxide layer pattern 13a becomes half that of the photoresist film pattern 12a (refer to FIGS. 2A and 2B), thereby forming an even smaller micro patterns.

Referring to FIGS. 6A and 6B, an anisotropic etch process using the oxide layer pattern 13a (refer to FIGS. 5A and 5B) as etch masks is performed to form hard mask pattern 11a. In other words, the oxide layer pattern 13a is used as hard masks for forming the underlying hard mask pattern 11a. The oxide layer pattern 13 is removed using a well-known technique.

Referring to FIGS. 7A and 7B, an etch process using the hard mask pattern 11a (refer to FIGS. 6A and 6B) as etch masks is performed to form semiconductor substrate pattern 10a. The hard mask pattern 11a is removed using a well-known technique.

In accordance with the method of forming a pattern of a semiconductor device according to the present invention, the surfaces of photoresist are changed to oxide layers. Patterns are formed using the oxide layers formed on the sides of the photoresist patterns. Accordingly, even smaller micro patterns can be formed. This enables higher-integration and smaller micro devices to be formed.

While the present invention has been described with reference to the particular illustrative embodiments, it is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention and appended claims. For example, in the present embodiment, it has been described that the method is applied to form the connector patterns in the peripheral region. However, it would be evident to those skilled in the art that the method may be applied to form independently formed patterns.

Claims

1. A method of forming a pattern of a semiconductor device, the method comprising: forming a hard mask layer over a semiconductor substrate;forming a photoresist film pattern over the hard mask layer;converting an outer portion of the photoresist film pattern into an oxide layer having a first vertical wall, a second vertical wall, and a horizontal wall, wherein an inner portion of the photoresist film pattern is enclosed within the converted oxide layer;removing at least a portion of the horizontal wall to expose the photoresist film pattern remaining within the converted oxide layer;removing the exposed photoresist film pattern to form first and second oxide patterns corresponding to the first and second vertical walls, respectively, of the oxide layer;patterning the hard mask layer using the first and second oxide patterns as etch masks; andetching the semiconductor substrate using the patterned hard mask layer.

2. The method of claim 1, wherein the converting step comprises: coating a silylation reagent on the photoresist film pattern; andthermally treating the coated photoresist film pattern.

3. The method of claim 1, wherein the oxide layer includes SiO2.

4. The method of claim 1, wherein the removing-at-least-a-portion-of-the-horizontal-wall step involves an etch back step.

5. The method of claim 1, wherein the removing-at-least-a-portion-of-the-horizontal-wall step involves a chemical mechanical polishing step.

6. The method of claim 2, wherein the silylation reagent includes at least one selected from the group consisting of hexamethyl disilazane (HMDS), tetramethyl disilazane (TMDS), bisdimethyl amino methylsilane (BDMAMS), bisdimethyl amino dimethylsilane, dimethylsilyl dimethylamine, dimethylsilyl diethylamine, trimethylsilyl diethylamine and dimethyl amino pentamethylsilane.

7. A method of forming a pattern of a semiconductor device, the comprising: forming a hard mask layer over a semiconductor substrate;forming a photoresist pattern over the hard mask layer;converting an outer portion of the photoresist pattern into a layer of different material, the converted layer having first, second, and third portions that together enclose an inner portion of the photoresist pattern, the first and second portions extending vertically and the third portion extending horizontally;removing the third portion of the converted layer to expose the photoresist pattern remaining within the converted layer;removing the exposed photoresist pattern to obtain first and second patterns corresponding to the first and second portions, respectively, of the converted layer; andpatterning the hard mask layer using the first and second patterns.

8. The method of claim 7, wherein the converted step comprises: coating a silylation reagent on the photoresist pattern; andbaking the coated photoresist pattern.

9. The method of claim 7, wherein the converted layer is an oxide including SiO2.

10. The method of claim 7, further comprising etching the substrate using the patterned hard mask layer.

11. The method of claim 7, wherein the hard mask layer includes nitride.

12. The method of claim 8, wherein the silylation reagent includes at least one selected from groups consisting of hexamethyl disilazane (HMDS), tetramethyl disilazane (TMDS), bisdimethyl amino methylsilane (BDMAMS), bisdimethyl amino dimethylsilane, dimethylsilyl dimethylamine, dimethylsilyl diethylamine, trimethylsilyl diethylamine and dimethyl amino pentamethylsilane.

13. A method of forming a pattern of a semiconductor device, the method comprising: providing a semiconductor substrate having a target layer;forming a photoresist pattern having a pitch;converting an outer portion of the photoresist pattern into an oxide layer;removing a portion of the oxide layer to expose the photoresist pattern remaining within the converted oxide layer;removing the remaining photoresist pattern to form first and second patterns, each having a pitch that is smaller than the pitch of the photoresist pattern; andetching the target layer using the first and second patterns as etch masks.

14. The method of claim 13, wherein the oxide layer includes SiO2.

15. A method of forming a pattern on a substrate, the comprising: forming a mask layer over a semiconductor substrate;forming a first pattern over the mask layer, the first pattern being of first material;converting an outer portion of the first pattern into a layer of second material, the converted layer having first, second, and third portions that together enclose an inner portion of the first pattern of the first material, the first and second portions extending vertically and the third portion extending horizontally;removing the third portion of the converted layer to expose an inner portion of the first pattern remaining within the converted layer;removing the exposed inner portion of the first pattern to obtain second and third patterns of the second material; andpatterning the mask layer using the second and third patterns.

16. The method of claim 15, wherein the second and third patterns correspond to the first and second portions, respectively, of the converted layer.

17. The method of claim 16, wherein the first material includes photoresist.

18. The method of claim 17, wherein the second material includes oxide, wherein the second and third patterns together comprises a pattern.

19. The method of claim 17, further comprising: etching the semiconductor substrate using the patterned mask layer, wherein the mask layer is a hard mask layer.

20. The method of claim 17, wherein the converting step comprises: coating a silylation reagent on the first pattern; and baking the coated first pattern.