JPH06138669A - Pattern forming method - Google Patents

Abstract

PURPOSE:To form a resist pattern with good shape by clarifying the contrast between an exposing part and an unexposing part at the time of sillylation. CONSTITUTION:On a substrate 1, a resist 2 consisting of naphthoquinone diazide and a resin is applied, and then a heating process for bridging mutual resins or naphthoquinone diazide and the resin, a pattern exposure process using a desired mask 4, a process for forming a mono-molecular layer containing Si on a pattern exposing part of the resist 2 and a process for forming a resist pattern 2A by selectively developing the resist 2 by dry etching are executed to form a pattern. By sillylation in which the contrast between the exposing part and the unexposing part is clarified, the pattern forming with good shape is realized and thereby an industrial production of the device in good yield is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine pattern forming method in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art Conventionally, a fine pattern forming method has been
Only the resist surface consisting of futoquinone diazide and resin
Of resist for high-resolution pattern formation using TiO2
And O ₂Etching method has been proposed (tato
For example, F. Coopmans et al., Proc. Of SPIE, vol.631,
p.34 (1986)). However, with this method, unexposed areas
It is said that the pattern shape deteriorates due to silylation.
Problems may occur.

An example of the conventional pattern forming method described above will be described below with reference to the drawings.

FIG. 2 is a process sectional view of a conventional pattern forming method. A resist composed of naphthoquinonediazide and resin (PLA manufactured by Japan Synthetic Rubber) is formed on the substrate 1.
SMASK301-U) 2 is formed by coating 1.5 μm (FIG. 2 (a)). Exposure 5 is performed using a KrF excimer laser stepper (NA 0.42) through the mask 4 (see FIG. 2).
(B)). And 180 with hexamethyldisilazane
Processing 6 of 90 ° C. is performed (FIG. 2 (c)). O ₂ RIE
The unexposed portion is removed at 7 to form a pattern 2C (FIG. 2D). However, since the unexposed portion 2D was also silylated, the 2D could not be completely removed by O ₂ RIE, and the pattern was deteriorated. Such a deteriorated pattern leads to a defect in a later process and eventually causes a reduction in the yield of the device.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a fine pattern forming method which prevents silylation of a resist unexposed area and makes full use of the characteristics of the silylation method.

[0006]

In order to solve the above problems, the pattern forming method of the present invention newly includes a step of heating such that the resins or the naphthoquinonediazide and the resin are crosslinked.

That is, according to the present invention, a step of applying a resist consisting of naphthoquinone diazide and a resin on a substrate and performing heating so that the resins or the naphthoquinone diazide and the resin are crosslinked, and a desired mask are used. A step of performing pattern exposure, and Si on the pattern exposed portion of the resist.
And a step of forming a resist layer by selectively developing the resist by dry etching to form a resist pattern.

[0008]

According to the present invention, when the resist film is formed by the above-mentioned method, the unexposed portions of the resist are crosslinked very efficiently by performing heating so that the resins in the resist or the naphthoquinonediazide and the resin are crosslinked. Moreover, the silylation reaction of the unexposed portion of the resist is prevented, only the exposed portion is silylated, and the unexposed portion is completely removed by O ₂ etching, so that a fine pattern having a good shape can be formed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pattern forming method according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a pattern forming method in an embodiment of the present invention. On the semiconductor substrate 1, a resist (PLASMASK301-U made by Japan Synthetic Rubber) 2 composed of naphthoquinonediazide and a resin is applied in a thickness of 1.5 μm (FIG. 1 (a)), and heating 3 at 130 ° C. for 90 seconds is performed (FIG. 1). (B)). Exposure 5 is performed using a KrF excimer laser stepper (NA 0.42) through the mask 4 (see FIG. 1).
(C)). Then, a process for forming a monomolecular layer containing Si on the surface of the resist 2 is performed. For example, a treatment with hexamethyldisilazane vapor 6 at 180 ° C. for 90 seconds is performed (FIG. 1 (d)). The unexposed portion 2B is removed by O ₂ RIE7 to form a pattern 2A (FIG. 1 (e)). Since the unexposed portion 2B was not silylated due to the crosslinking of the unexposed portion due to the heating after the application of the resist, it was completely selectively dry-developed by O ₂ RIE so that only the exposed portion pattern 2A remained. As a result, the pattern 2A could be a 0.25 μm pattern having a good shape with no pattern connection.

The heating is optional as long as the temperature and time are such that the resins or the naphthoquinonediazide and the resin are crosslinked. For example, the temperature is about 130 ° C. and the time is about 90 seconds. Not limited to this. The influence of the crosslinking on the exposed portion of the pattern exposure due to this heating can be ignored because the energy of the pattern exposure is higher.
Examples of the silylation method include coating and vapor deposition. Examples of silylation materials include, but are not limited to, disilazane compounds (eg, hexamethyldisilazane, tetramethyldisilazane, etc.) and trisilazane compounds. Examples of resins include, but are not limited to, novolac resins and phenol resins.

[0012]

As described above, according to the present invention, a pattern having a good shape can be formed by heating such that the resins in the resist or the naphthoquinonediazide and the resin are crosslinked during the formation of the resist film, and the yield of semiconductor elements can be improved. It greatly contributes to the improvement.

[Brief description of drawings]

FIG. 1 is a process sectional view of a pattern forming method in an embodiment of the present invention.

FIG. 2 is a process sectional view of a conventional pattern forming method.

[Explanation of symbols]

1 substrate 2 resist 3 heating 4 mask 5 KrF excimer laser light 6 hexamethyldisilazane vapor 7 O ₂ RIE 2A, 2C patterns 2B, 2D unexposed part

Claims (1)

[Claims] 1. A step of applying a resist comprising naphthoquinone diazide and a resin on a substrate and performing heating so that the resins or the naphthoquinone diazide and the resin are cross-linked.
A step of pattern exposure using a desired mask, a step of forming a monomolecular layer containing Si in the pattern exposed portion of the resist, and a step of selectively developing the resist by dry etching to form a resist pattern And a pattern forming method comprising: