KR100220940B1 - Method of manufacturing fine pattern of semiconductor device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fine pattern of a semiconductor device, wherein a photoresist film pattern for lift-off is formed on an interlayer insulating film, and a dummy pattern is formed at a portion corresponding to the end of the pattern at a portion that is intended as a pattern on a wafer in an exposure mask. By selectively exposing using an exposure mask having an overcoat, the sidewall edge portion of the photoresist pattern is formed to have an overhang, thereby forming a fine pattern having a line width of less than four micros, which is stable in a lift-off process, and is advantageous for high integration of the device. The margin can be improved to improve process yield and device operation reliability.

Description

Manufacturing method of fine pattern of semiconductor device

1 is a plan view of an exposure mask used in a micropattern manufacturing process of a semiconductor device according to the prior art.

2 (a) to 2 (c) is a process chart showing a fine pattern of a semiconductor device according to the prior art.

3 is a plan view of an exposure mask used in the process of manufacturing a fine pattern of a semiconductor device according to the present invention.

4 (a) to 4 (c) is a fine pattern manufacturing process diagram of a semiconductor device according to the present invention.

* Explanation of symbols for main parts of the drawings

1,6: Exposure mask 2,7: Transparent substrate

3,8 exposure area 4,9 light blocking film pattern

10: dummy pattern 11; Interlayer insulation film

12 photosensitive film 13 conductive layer

14: overhang

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fine pattern of a semiconductor device, and in particular, dummy patterns are formed on both sides of an exposure area defined by a light blocking film pattern of an exposure mask for lift off, thereby preventing pattern defects during lift off. The present invention relates to a method of manufacturing a fine pattern of a semiconductor device which can easily form a fine pattern and improve process yield and device operation reliability.

Recently, the trend of high integration of semiconductor devices has been greatly influenced by the development of fine pattern formation technology, and the miniaturization of photoresist patterns, which are widely used as masks such as etching or ion implantation processes, are essential in the manufacturing process of semiconductor devices.

Looking at the manufacturing process of the photosensitive film pattern according to the prior art as follows.

First, a photoresist is formed by coating a photoresist in which a predetermined substructure is formed to form a curved pattern on the surface of the semiconductor substrate in which a photoresist and a resin are dissolved in a solvent having a predetermined ratio. By selectively irradiating light using an exposure mask having a light blocking film pattern formed at a position corresponding to a portion of the photoresist that is intended as a pattern on the transparent substrate, the portion intended to be polymerized is formed.

Then, the wafer subjected to the exposure process was subjected to a soft bake heat treatment process at a temperature of 80 to 120 ° C. for 60 to 120 seconds in a heat treatment apparatus, and then a weak alkaline developer containing TMAH (tetra methylammonium hydroxide) as a main material was used for the photosensitive film. The exposed / non-exposed areas are selectively removed, the wafer is washed with deionized water and then dried to form a photoresist pattern.

The resolution R of the photoresist pattern is proportional to the wavelength? And the process variable k of the light source of the reduction exposure apparatus, and inversely proportional to the numerical aperture NA of the exposure apparatus.

Here, the wavelength of the light source is reduced to improve the optical resolution of the reduced exposure apparatus. For example, the G-line and i-line reduced exposure apparatus having wavelengths of 436 and 365 nm have a process resolution of about 0.7 and 0.5 μm, respectively. Is the limit.

Therefore, in order to form a fine pattern of 0.5 μm or less, an exposure apparatus using a deep ultra violet, for example, a KrF laser having a wavelength of 248 nm or an ArF laser having a wavelength of 193 nm, may be used as a light source, or image contrast may be used. A contrast enhancement layer (CEL) method or a phase inversion mask may be used to form a separate thin film on the wafer.

However, there is a limit in converting the light source of the equipment to the fine wavelength, and the CEL method is complicated and the yield is low.

In addition, as another embodiment of the prior art, the TLR method in which an intermediate layer is interposed between two photoresist layers rather than the single layer resist method is capable of forming a fine pattern having improved resolution by about 30% compared to the single layer photoresist method due to the small process parameters. It is difficult to form patterns of about 0.2 to 0.25 µm, which is required for highly integrated semiconductor devices of 1G DRAM or more, and thus there is a limit to high integration of devices.

1 is a plan view of an exposure mask for a lift-off process used in a micropattern manufacturing process of a semiconductor device according to the prior art, wherein the exposure mask 1 is a pattern on a transparent substrate 2 made of a transparent material such as quartz or glass. The light blocking film pattern 4 defining the exposure areas 3 exposing the predetermined portions is formed of a light blocking material pattern such as Cr.

Here, the exposure mask 1 is a positive photoresist exposure mask 1 for forming a line width below the submicron by a lift-off method.

2 (a) to 2 (c) are microfabrication process diagrams of a semiconductor device according to the prior art, and are examples of using the exposure mask of FIG.

First, a lower structure of the device, for example, a MOS field effect transistor, a capacitor, a bit line, etc. are formed, and an interlayer insulating film 11 is formed on the entire surface of the structure, and then metal wiring is lifted from the interlayer insulating film 11. The photosensitive film 12 pattern which exposes a part is formed by exposing and developing using the exposure mask 1 shown in FIG. Here, the photosensitive film 12 is a positive photosensitive film 12 having a non-exposed area as a pattern (see also second (a)).

Then, after forming a conductive layer 13 made of a material, for example, polysilicon or metal, to form a pattern on the entire surface of the structure (see also the first (b)), the photosensitive film pattern 12 ) And the upper conductive layer 13 are removed by a lift-off method to form conductive wiring in a pattern of the conductive layer 13 (see also first (c)).

In the method of manufacturing a fine pattern of a semiconductor device according to the prior art as described above, when the pattern is formed by the lift-off method, the micro pattern is exposed to an appropriate exposure value that compensates for various effects, so that the photosensitive film 12 pattern has a vertical sidewall shape. The conductive layer 13 is applied to the sidewalls of the photosensitive film 12 pattern, so that the lift-off may not be properly performed when the conductive portions 13, which are the patterns and the upper and lower conductive layers 13, which are lifted off are connected to each other. As a result, a pattern defect is generated, which is severely generated at the end portion of the exposure area 3 of the exposure mask, making it difficult to integrate a device and reducing the process yield and reliability of device operation.

In order to solve the above problems, there is a method of forming an overhang on the upper sidewall of the photoresist pattern by performing overexposure during the exposure process for forming the photoresist pattern. There is no problem that can form a fine pattern.

The present invention is to solve the above problems, an object of the present invention is to form a dummy pattern on the portion corresponding to the end of the portion that is intended as a pattern in the exposure mask for lift-off part during the exposure and development process A method of manufacturing a fine pattern of a semiconductor device that can form a fine line width pattern easily by forming an overhang on the photoresist pattern of the semiconductor layer, and is advantageous for high integration of the device, and improves process yield and reliability of device operation. In providing.

According to an aspect of the present invention, there is provided a method of manufacturing a fine pattern of a semiconductor device, the method including forming an interlayer insulating film on the entire surface of a semiconductor substrate having a predetermined structure, applying a photosensitive film on the interlayer insulating film, Exposing the photosensitive film, and exposing the photosensitive film with an exposure mask having a dummy pattern at a portion corresponding to a portion scheduled as the end of the pattern; developing the exposed photosensitive film and having an overhang on an upper sidewall of the pattern. Forming a pattern, forming a conductive material layer to form a pattern on the entire surface of the structure, and removing the photosensitive film pattern and the conductive material layer thereon by a lift-off method to form the interlayer insulating film. It is to form a conductive material layer pattern.

Hereinafter, a method of manufacturing a fine pattern of a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a plan view of an exposure mask used in a micropattern manufacturing process of a semiconductor device according to the present invention, which is a lift-off exposure mask for forming a positive photoresist pattern having a line width of submicro.

First, the exposure mask 6 includes a light blocking film pattern 9 that defines exposure areas 8 exposing portions intended as a pattern on a transparent substrate 7 made of a transparent material such as quartz or glass. The light blocking material pattern is formed, and dummy patterns 10 for overhanging are formed at both ends of the exposure area 8.

4 (a) to 4 (c) are fine-pattern manufacturing process diagrams of a semiconductor device according to the present invention, which is an example of a lift-off method using the exposure mask of FIG.

First, an interlayer insulating film 11 is formed on a semiconductor substrate (not shown) having a predetermined structure, and a photosensitive film 12 is formed on the interlayer insulating film 11, and then the photosensitive film 12 is formed in FIG. The photosensitive film 12 pattern is exposed to the exposure mask 6 including the dummy pattern 10 and developed to have an overhang 14 at the edge of the sidewall, and to expose the portion where the pattern is to be raised in the interlayer insulating film 11. (See also fourth (a)).

Then, after applying a conductive layer 13 such as a silicon layer or a conductive material such as a metal to the entire surface of the structure (see also fourth (b)), the photosensitive film 12 pattern and the conductive layer thereon (13) is removed by a lift-off method to form conductive wiring in a pattern of the conductive layer 13. At this time, the lift-off of the conductive layer 13 pattern is smoothly performed by the overhang 14 without a short circuit or the like (see also fourth (c)).

In the above description, the exposure mask using the positive photoresist film has an example of having a dummy pattern in which an exposure area is extended. However, in the case of a negative photoresist film, the present invention can be applied using an exposure mask having an inverted image. Of course.

As described above, the method for manufacturing a fine pattern of a semiconductor device according to the present invention forms a photoresist film pattern for lift-off on an interlayer insulating film, and corresponds to the end of the pattern at a portion that is intended as a pattern on a wafer in the exposure mask. By selectively exposing using an exposure mask having a dummy pattern in the portion to form an overhang in the sidewall edge portion of the photosensitive film pattern, a fine pattern having a line width of submicro or less stable by the lift-off process was formed. Advantageously, there is an advantage that the process margin can be improved to improve process yield and reliability of device operation.

Claims (1)

Forming an interlayer insulating film on the entire surface of the semiconductor substrate having a predetermined structure; applying a photosensitive film on the interlayer insulating film; and exposing the photosensitive film to a portion corresponding to a portion intended to be the end of the pattern. Exposing with an exposure mask having a pattern; developing the exposed photoresist to form a photoresist pattern having an overhang on an upper sidewall of the pattern; and a conductive material layer to form a pattern on the entire surface of the structure. Forming a conductive material layer pattern formed on the interlayer insulating film by removing the photoresist pattern and the conductive material layer thereon by a lift-off method.