KR950004976B1 - Method of forming positive type resist pattern - Google Patents

Abstract

The method includes the steps of applying a photoresist (2) on a substrate (1) to expose the upper resist portion by a mask to convert the exposed resist region into an acid portion (9), performing an amine bake process by using amonia as a catalyst to form a decarboxylation reaction material region (11) not reacting with lights, exposing the whole resist surface to ultraviolet rays to convert the residual resist region into an acid portion (9), implanting silicon material into the acid portion (9), oxidizing the Si implanted resist region by an O2 plasma treatment to form a mask, and removing the residual region (11) and the lower resist (2) thereof, thereby using positive resist processes in a lithography process to form a microresist pattern (20).

Description

Portage resist formation method

1A to 1C are cross-sectional views showing a conventional resist pattern forming method.

1A is a sectional view of a state in which a resist is applied onto a substrate and then exposed to ultraviolet rays.

FIG. 1B is a cross-sectional view after silicide reaction. FIG.

1C is a cross-sectional view of a pattern formed by oxygen plasma processing.

2A to 2E are sectional views showing the resist pattern forming method of the present invention.

2A is a sectional view of a state in which a resist is applied onto a substrate and then exposed to ultraviolet rays.

Figure 2b is a sectional view after the amine baking step.

FIG. 2C is a cross-sectional view of the entire surface exposed state. FIG.

2d is a cross-sectional view after the silicide reaction.

FIG. 2E is a cross-sectional view of a pattern formed by oxygen plasma treatment. FIG.

* Explanation of symbols for main parts of the drawings

1 substrate 2 photoresist

2A: patterned resist 3: exposure area

4: mask 5: ultraviolet rays

6: silicon diffusion layer 6A: silicon diffusion layer swing pattern

7: oxide film 9: acid

10: negative resist pattern 11: new product

20: positive resist pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a positive resist pattern of a highly integrated semiconductor device, and more particularly, to a lithography process in which a positive resist pattern is formed on a substrate using a silylation reaction.

As the semiconductor devices are highly integrated, silicide reactions are frequently used to form fine resist patterns. However, in the conventional lithography process, a negative resist pattern is formed by a conventional resist pattern forming process. It is difficult to apply the method. However, the present invention can solve the above problems by forming a positive resist pattern using.

Referring to FIGS. 1A to 1C, a method of forming a resist pattern using a conventional silication reaction is described with reference to FIGS. 1A through 1C. The state where the surface of the resist 2 was exposed by ultraviolet ray 5 is shown.

The resist (2) contains diaazonaphthoquinone and Novolac Resin. When exposed to ultraviolet light (5), the diazona contained in the resist (2) in the exposure area (3) is exposed. The ptoquinone is changed to the acid 9, and at the same time, the mask boundary region is also exposed to the acid 9 by the light fading phenomenon, so that a swing pattern 6A is formed at the boundary region.

FIG. 1B shows a silicide reaction after the process of FIG. 1A. When the silicide reaction is carried out, the silicon contained in the silicide solvent diffuses only in the region where the acid 9 is changed on the resist 2, thereby swinging in the shape of a wing. The silicon diffusion layer 6 including the ching pattern 6A is formed.

In FIG. 1C, a resist pattern is formed by oxygen plasma treatment after the process in FIG. 1B. Here, the oxygen plasma etches the resist 2 in the non-exposed area and simultaneously reacts with the silicon deposition layer 6 in the exposed area to react with the oxide film 6 to form the oxide film 7, which is an oxide film 7. ) Serves as a mask for the oxygen plasma, thereby forming a negative resist pattern 10 in which the exposure area remains as a pattern.

At this time, when the resist 2 is dry developed with oxygen plasma, the swing pattern 6A generates an undercut in the lower resist 2 so that the profile of the negative resist pattern 10 is not constant. This makes it difficult to adjust the line width of the pattern.

Therefore, the negative resist pattern generated by the above process step is difficult to apply to the general resource-rape process because it is inevitable to change the mask fabrication and the process conditions in addition to the problem of the negative process itself, so that the positive resist that can solve all the problems It is an object of the present invention to provide a pattern forming method.

The resist pattern forming method using the silicide of the present invention will be described with reference to FIGS. 2A through 2E. FIG. 2A shows the resist 2 on the substrate 1 and then the upper part of the resist 2. It is sectional drawing which showed the state which changed the resist 2 of the exposed area | region to the acid 9 by putting the mask 4 on the surface, exposing with the ultraviolet-ray 5, and FIG.

At this time, the resist (2) is added to the existing resist containing diazonaphthoquinone and novolak resin further added Monazoline, imidazole, and triethanolamine. The diazonaptoquinone contained in the resist 2 of (3) is changed into the acid (9). Here, as shown in FIG. 1A, since the mask boundary region is exposed to a mountain, a swing pattern 6A is formed.

FIG. 2b shows an amine bake process using ammonia as a catalyst after the FIG. 2a process. When the amine bake process is performed, the acid 9 in the exposure area 3 of FIG. 2a generates carbon dioxide. A new product (11) that does not react with light, for example, is transformed into a decarboxylation reaction product. At this time, the resist 2 in the non-exposed area is not changed by the amine baking process and preserves the properties of the first resist 2 as it is.

FIG. 2C is a full exposure by ultraviolet light 5 after the process of FIG. 2B to change the predetermined thickness on the resist 2 in the non-exposed areas shown in FIG. 2A to acid 9, and FIG. It is shown that it is preserved as it is not affected by the ultraviolet rays of the new product 11 in the primary exposure area.

FIG. 2d shows the post-silation process of FIG. 2c, where the acid 9 is generated during the entire exposure to form the silicon diffusion layer 6, and the portion with the new product 11 is free of silicon diffusion. The state is shown.

FIG. 2E is a dry pattern developed by oxygen plasma after FIG. 2D process to form a resist pattern. The new product 11 and the resist 2 under the silicon that are not diffused are etched and the silicon diffusion layer 6 is present. The portion shown in FIG. 2 shows that an oxide film 7 is formed by reacting silicon with oxygen to serve as a mask for the plasma, thereby forming a positive resist pattern 20 in which the exposure area in the first exposure of FIG. 2a is etched.

Since the positive resist pattern formed by the present invention is most of the lithography process used in the manufacture of semiconductor devices, it is applicable to the actual process without changing the mask fabrication and process conditions as compared to the conventional negative process using the silicide. There is an advantage to this.

In addition, the conventional negative resist pattern is made of a resist profile undercut by a swinging pattern formed in the exposure area, whereas in this process, even if a swing pattern occurs in the exposure area, the non-exposed area remains as a pattern after oxygen plasma treatment. It is easy to control the line width because there is no undercut phenomenon caused by the pattern.

Claims (3)

In the resist pattern forming method, a resist is applied on a substrate, a mask is placed on top of the resist, and a predetermined thickness of the resist is exposed to change the exposed resist region to acid, and an amine catalyzed by ammonia. Performing a bake process to form the acid-converted resist into a new product that does not react with light; exposing ultraviolet light to the entire surface of the resist to convert the resist in the portion not formed with the new product into acid; Injecting silicon into the acid-converted resist by the silication reaction, and oxidizing the silicon-infused resist by oxygen plasma treatment to act as a mask, and remove the new product and the underlying resist not implanted Positive resist, characterized in that consisting of Pattern formation method. The method of claim 1, wherein the resist is a resist in which monazoline, imidazole, and treethanolamine are added to a conventional resist containing diazonaphthoquinone and novolak resin. The method of claim 1, wherein the new product is formed of a decarboxylation reaction product.