JPH02177318A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a fine pattern without using an expensive method by exposing the side face of a positive photoresist film so as to form a photosensitive layer, and forming a photoresist film which has fine patterns making use of the thickness of its photosensitive layer. CONSTITUTION:An Si oxide film 2 is formed on an Si substrate 1, and a positive photoresist film 3 is formed on the film 2, and is patterned. Next, the upper face and side face of the film 3 is exposed so as to form a photosensitive layer 4. Next, a positive photoresist film 5 is formed at the surface inclusive of the film 3 and film 4. Next, by development the film 5 on the layer 4 and the top of the layer 4 are removed, and at the same time the side of the layer 4 is removed so as to form an opening 6. Next, with the film 3 and 5 as masks, the film 2 and the substrate 1 are etched anisotropically in order and grooves 7 are formed. Hereby, fine patterns can be formed without using an expensive method unsuitable for mass-production.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming a fine pattern.

[Conventional technology]

Conventional semiconductor device manufacturing methods use reduction projection exposure methods, exposure methods using electron beams, and more recently exposure methods using lasers and accelerated particles to turn the photoresist layer for fine patterns to increase the width. A fine pattern of about 1 μm is formed.

[Problem to be solved by the invention]

In the conventional semiconductor device manufacturing method described above, when exposing a pattern using light, there is a limit to the resolution depending on the wavelength of the light, etc., so it is impossible to form a turn of 0.5 μm or less. When using accelerated particles such as a beam, it has better resolution than light, but when considering the cost of the equipment, throughput, etc., it is inefficient to use these methods in mass production processes. There is a point.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device that can form a fine pattern without using an expensive method that is unsuitable for mass production.

[Means to solve problems]

The method for manufacturing a semiconductor device of the present invention includes the steps of sequentially forming a film to be etched and a positive first photoresist film on a semiconductor substrate, and after buttering the first photoresist film, the first photoresist film is patterned. A step of exposing the photoresist film for a predetermined time to form a photosensitive layer on the top and side surfaces of the photoresist film, forming a positive second photoresist film on the entire surface including the photosensitive layer, and then forming a positive photoresist film on the entire surface including the photoresist film. removing the second photoresist film by development until the surface is exposed, and simultaneously removing the photosensitive layer on the side surface to form an opening;
The method includes a step of etching the film to be etched using the photoresist film as a mask.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(f) are cross-sectional views of a semiconductor chip shown in order of steps for explaining a first embodiment of the present invention,
This shows a case where the present invention is applied to groove separation.

First, as shown in FIG. 1(a), a silicon oxide film 2 is formed on a silicon substrate 1, and a positive type first photoresist film 3 with a thickness of 2 Lm is formed on the silicon oxide film 2. Form and butter.

Next, as shown in FIG. 1(b), the top and side surfaces of the first photoresist film 3 are exposed to a depth of 0.3 μm to form a photosensitive layer 4.

Next, as shown in 1[](c), a positive type second photoresist film 5 is formed on the surface including the first photoresist film 3 and the photosensitive material N4 by a coating method.

Next, as shown in FIG. 1(d), the second photoresist M5 on the photosensitive layer 4 and the photosensitive layer 4 on the top surface are removed by development, and at the same time, the photosensitive layer 4 on the side surfaces is removed to form the opening 6. Form. At this time, as the first photoresist pIA3,
For example, when using 0FPR800C (manufactured by Tokyo Ohka Kogyo Co., Ltd.), the dissolution rate of the unexposed area in a developer such as NMD-3 (manufactured by the same company) is about 0.1 μrn/min at room temperature, and the Similarly, although the dissolution rate is approximately 2 μm/min, if the thickness of the second photoresist film 5 on the photosensitive M4 is 1 μIn, a development time of 11 minutes is required. Here, before development, the second photoresist film 5 is coated one layer from the surface.
By exposing to the depth of the μr port, the development time can be shortened to 1.5 minutes.

Next, as shown in FIG. 1(e), using the first and second photoresist films 3 and 5 as masks, the silicon oxide film 2 and silicon substrate 1 are sequentially etched by RIE to a depth of 0. .3 μm groove 7 is formed.

Next, as shown in FIG. 1(f), after removing the first and second photoresist films 3 and 5, the trenches 7 are removed by thermal oxidation.
By forming the silicon oxide film 8 on the
m groove separation is completed. At this time, in addition to the thermal oxidation method, SOG method (spin-on glass) or LPC using silica film etc.
The VD method may also be used to fill the insulator or polysilicon to the full extent. Figures 2(a) to 2(e) show semiconductor chips in order of process for explaining the second embodiment of the present invention. A cross-sectional view,
This shows a case where the present invention is applied to flat wiring formation.

First, as shown in FIG. 2(a), after a device is formed on a silicon substrate 1, a silicon oxide film 2 is formed thereon, and a contact hole 9 is formed by sputtering aluminum WilO with a thickness of 1 μm over the entire surface. A positive type first photoresist II with a thickness of 2 μm is deposited on the zero-order aluminum film 1o deposited by ! Form 3 and butter.

Next, as shown in FIG. 2(b), after exposing the top and side surfaces of the first photoresist film 3 to a depth of Ojμ 1 to form a photosensitive layer 4, a second positive type film is coated on the entire surface. A photoresist M5 is formed by a coating method.

Next, as shown in FIG. 2(c), the second photoresist llll5 on the photosensitive layer 4 is removed by development, and at the same time, the photosensitive layer 4 is removed to form an opening 6.

Next, as shown in FIG. 2(d), using the first and second photoresist films 3 and 5 as masks, aluminum 110
After forming grooves 7 of 0.3 μm by anisotropic etching using the RIE method, the first and second photoresists WA3 are etched.
．． Remove 5.

Next, as shown in FIG. 2(e), the top and side surfaces of the aluminum film IO are coated with aluminum oxide pA by anodizing.
Change it to 11. At this time, when the aluminum changes to porous aluminum oxide, the volume expands approximately 1.3 times, so the groove 7 is filled with the aluminum oxide film 11. Although the anodic oxidation method is used here, the groove 7 may be filled with an insulator using an SOG method using a silica film, a plasma nitride film, or a plasma oxide film method.

〔Effect of the invention〕

As explained above, the present invention exposes the side surface of a positive photoresist film to form a photosensitive layer, and utilizes the thickness of the photosensitive layer to form a photoresist film having a fine pattern of 1 μm. Since grooves having the following fine patterns can be easily formed on the object to be etched, there is an effect that the degree of integration of semiconductor devices can be improved.

[Brief explanation of the drawing]

FIGS. 1(a)-(f) and FIGS. 2(a)-(e) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining the first and second embodiments of the present invention. 1... Silicon substrate, 2... Silicon oxide film, 3.
...first photoresist film, 4...photosensitive layer, 5...
- Second photoresist film, 6... opening, 7...
Groove, 8... silicon oxide layer, 9... contact hole,
10... Aminium film, 11... Aluminum oxide film.

Claims (1)

[Claims] A step of sequentially forming a film to be etched and a positive first photoresist film on a semiconductor substrate, and after patterning the first photoresist film, exposing the first photoresist film for a predetermined time to expose the upper surface thereof. and a step of forming a photosensitive layer on the side surface, and a step of forming a positive type second layer on the entire surface including the photosensitive layer.
After forming a photoresist film, removing the second photoresist film by development until the surface of the first photoresist film is exposed, and simultaneously removing the photosensitive layer on the side surface to form an opening; A method of manufacturing a semiconductor device, comprising the step of etching the film to be etched using the first and second photoresist films separated by an opening as a mask.