JPH0745510A - Pattern formation method - Google Patents

Abstract

(57) [Summary] [Structure] After forming a resist pattern, a resin 4 is applied to the entire surface, and then the resist 2 is fluidized by heat treatment to make the pattern fine. [Effect] Since the heat flow of the resist is caused after the resin is applied, excessive flow can be prevented, and the dimensions can be stabilized.
It is possible to realize the miniaturization of the hole pattern for taking out electrodes of the VLSI, which is difficult to miniaturize.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for finely processing an element by a lithography method.

[0002]

2. Description of the Related Art In recent years, elements have been miniaturized, and further miniaturization has been required for lithography. In particular, the hole pattern for electrode formation is more difficult to be miniaturized than the wiring pattern due to the resolution characteristics of the stepper, and development of miniaturization technology is required. As a method for making the hole pattern finer, as described in JP-A-1-307228, there is a method of making the pattern fine by heat-flowing the resist after forming the resist pattern and then performing heat treatment at a temperature higher than the resist softening point. . However, this method has problems that the inclination angle of the side wall of the resist pattern becomes gentle, a sufficient mask action cannot be obtained in the next substrate processing, and the dimensional controllability is poor.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pattern miniaturization method which is free from the problem of the above-mentioned prior art, that is, the side wall of the resist pattern and the deterioration of the dimensional controllability. .

[0004]

To solve the above problems, after forming a resist pattern, a resin immiscible with the resist (such as a water-soluble resin) is applied to the entire surface, and then heat treatment is performed to cause heat flow of the resist. After that, it is achieved by the step of removing the resin applied on the resist.

[0005]

Since the resin is coated on the resist pattern and heat flow is caused, the resin embedded in the resist serves as a stopper for resist flow, and pattern collapse due to excessive flow can be prevented. Further, it is possible to prevent the sidewall of the resist pattern from dripping.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. 1A to 1C are sectional views showing steps of the present invention. Figure 1
As shown in (a), the resist 2 was applied onto the substrate 1 to be processed. Here, a resist containing a positive novolac resin as a main component was used. Next, as shown in FIG. 1B, the resist in a desired portion was selectively removed by ordinary lithography. Next, as shown in FIG.
Water-soluble resin 4 was applied to the entire surface. Next, as shown in FIG. 1D, heat treatment was performed at a temperature equal to or higher than the softening point of the resist. Next, as shown in FIG. 1E, the water-soluble resin 4 was removed by washing with water.

Through the above steps, the resist removal region 3 formed by lithography is miniaturized and the resist removal region 5 is miniaturized.
Could be formed. The planar shape of the miniaturized pattern is a hole pattern, a linear pattern, or the like. As the resist 2, a resist containing a positive novolac resin as a main component was used, but a negative resist or a main component containing isoprene rubber, epoxy, polystyrene, acrylate, etc.
Any material that causes heat flow can be used. The resin 4 does not necessarily have to be water-soluble. It is necessary that the two do not mix when the resin 4 is applied onto the resist 2. The resin 4 can be replaced with an inorganic film. It is also necessary not to dissolve the resist 2 when removing the resin 4.

The method of removing the resin 4 is not limited to the wet method. It may be dry. For example, a method of removing it as a pretreatment of the dry etching of the substrate to be processed is also possible.

The softening point of the resin 4 is preferably higher than that of the resist 2. The temperature at which the novolac-based resist used here causes thermal flow is 120 ° C. or higher.

FIG. 2 shows the relationship between heat treatment time and hole diameter. A novolac-based resist is used for resist 2 and the film thickness is 1 μm
And Polyvinyl alcohol was used as the resin 4, the coating film thickness was set to 0.6 μm and 0.2 μm, the heat treatment time was changed and the change in the hole diameter was examined. The heat treatment temperature was 150 ° C. The hole diameter before heat treatment is 0.5 μm.

When the heat treatment time is 3 minutes and the film thickness of polyvinyl alcohol is 0.6 μm, the hole diameter is about 0.4 μm.
When the film thickness of polyvinyl alcohol was 0.2 μm, the hole diameter was about 0.3 μm. However, when the heat treatment time was further increased to 6 minutes and the polyvinyl alcohol film thickness was 0.6 μm, the hole diameter was about 0.4 μm, which was the same as that at 3 minutes. Polyvinyl alcohol film thickness is 0.2 μm
In the case of No. 2, the hole diameter was about 0.2 μm, but at the upper part of the hole, the hole diameter was widened and the side wall of the hole was sagging. In such a state, a sufficient mask action cannot be obtained in processing the substrate, which is a problem. It was possible to reduce the heat treatment time dependence of the hole diameter by increasing the film thickness of polyvinyl alcohol. As a result of examining various conditions, when the film thickness of the resist 2 is set to 1, the film thickness of the resin 4 is 0.3 to 1.
Particularly good results were obtained at 0 μm. Although increasing the heat treatment temperature tends to reduce the hole diameter, forming the resin layer can prevent the hole diameter from becoming too small. Here, polyvinyl alcohol was used as the resin 4, but as a result of experiments using other resins, data showing almost the same tendency was obtained.

[0012]

According to the present invention, a fine pattern exceeding the resolution limit can be formed by a simple process. In particular, it is possible to realize the miniaturization of the hole pattern for taking out electrodes of the VLSI, which is difficult to miniaturize, and the VLSI can be manufactured by using optical lithography.

[Brief description of drawings]

FIG. 1 is a sectional view showing a pattern forming process according to an embodiment of the present invention.

FIG. 2 is a graph showing the effect of the present invention.

[Explanation of symbols]

1 ... Substrate to be processed, 2 ... Resist, 3 ... Resist removal region, 4 ... Resin, 5 ... Miniaturized resist removal region.

Claims (4)

[Claims] 1. A step of forming a resist pattern on a substrate, a step of forming a resin immiscible with the resist on the entire surface or a part thereof, a heat treatment step, and a step of removing the resin immiscible with the resist. A method for forming a pattern characterized by the above. 2. The pattern forming method according to claim 1, wherein the resin immiscible with the resist is a water-soluble resin. 3. The pattern forming method according to claim 1, wherein the heat treatment step is performed at a temperature equal to or higher than a limit at which heat flow of the resist occurs or a temperature equal to or higher than a softening point. 4. A pattern forming method, wherein the resist pattern is a hole pattern.