JPH0784374A - Fine pattern forming method - Google Patents

Abstract

PURPOSE:To prevent the degradation of fidelity (halation) and the degradation of dimensional accuracy caused by standing wave effect without generating the fall and exfoliation of photoresist at the time of forming a fine photoresist pattern. CONSTITUTION:At the time of exposing and developing photoresist 5 applied onto a semiconductor substrate 1 to form a photoresist pattern, an exposure light absorbent is contained in the lower layer of the photoresist 5, and an organic film 7 is interposed to make dissolution proceed in the anisotropic state at the time of being submerged in a photoresist developer, water or an organic solvent. The lowering of contact area between the organic film 7 and the photoresist 5 after developing is thereby suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming a fine pattern, and more particularly to a technique effectively applied to the manufacture of a semiconductor integrated circuit device, a display device, a printed wiring board and the like using a photolithography technique.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process (wafer process), a fine pattern is formed on a semiconductor substrate by an etching technique using a photoresist pattern as a mask. However, as a problem in exposing a photoresist on a semiconductor substrate to form a fine photoresist pattern, deterioration of pattern fidelity due to sneak of exposure light reflected on the surface of the semiconductor substrate to a light shielding portion (halation). Also, it has been pointed out that the dimensional accuracy is deteriorated due to the standing wave effect.

Various multi-layer resist methods have been proposed as countermeasures, but among them, as a simple method, an exposure light absorber is contained between the semiconductor substrate and the photoresist,
There is known a technique of interposing an organic film soluble in a developer or water and preventing the above-mentioned halation and the like by the exposure light absorber in the organic film (for example, Japanese Patent Publication No. 3-76740).

[0004]

However, in the above-mentioned conventional technique, when the organic film is dissolved in a developing solution or the like, the dissolution proceeds isotropically. Therefore, as shown in FIG. The organic film 6 is undercut, and the contact area between the organic film 6 and the photoresist 5 is reduced. As a result, when a particularly fine photoresist pattern is to be formed, there arises a problem that the photoresist 5 falls over or peels off. Note that FIG.
Reference numeral 1 is a semiconductor substrate, 2 and 4 are insulating films, and 3 is a conductive film such as a polycrystalline silicon film.

An object of the present invention is to provide a technique capable of preventing deterioration of pattern fidelity (halation) and deterioration of dimensional accuracy due to a standing wave effect without causing the photoresist to fall or peel. It is in.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0007]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

The method for forming a fine pattern according to the present invention is
When forming a photoresist pattern on a substrate, first, an organic film that contains an exposure light absorber and is anisotropically dissolved when immersed in a photoresist developing solution, water or an organic solvent is formed. After coating, a photoresist is coated on this organic film, and exposure and development are performed.

[0009]

According to the above means, when the photoresist after exposure is developed, the organic film interposed between the substrate and the photoresist is anisotropically dissolved, so that the organic film and the photoresist come into contact with each other. Since the reduction of the area is suppressed, it is possible to prevent the photoresist from falling or peeling. Further, the exposure light absorber contained in this organic film can prevent halation and the like.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

Example 1 As shown in FIG. 1, an organic film 7 and a photoresist 5 were applied on a semiconductor substrate 1 on which an insulating film 2, a polycrystalline silicon film 3 and an insulating film 4 were sequentially formed.

That is, an organic film 7 made of a positive photoresist in which a novolac resin containing naphthoquinonediazide as a photosensitive group and an exposure light absorber are dissolved in cyclohexanone which is a polar solvent is formed on the insulating film 4 to a thickness of about 0.1 μm. After spin coating to a film thickness, baking was performed on a hot plate at 90 ° C. for 2 minutes. Next, a novolak resin containing naphthoquinonediazide as a photosensitive group, bis (4-t-butylphenyl) iodonium triflate which is a catalyst for generating an acid upon exposure, and THP-M (protecting polyvinylphenol with a tetrahydropyranyl group). And a photoresist 5 in which xylene is dissolved in xylene on the organic film 7 to a thickness of about 0.7 μm.
After spin coating to a film thickness of m, apply 80 on a hot plate.
Bake at ℃ for 2 minutes.

Next, the photoresist 5 and the organic film 7 under it were exposed by an exposure device using a KrF excimer laser as a light source, baked at 100 ° C. for 2 minutes, and then developed with an alkali developing solution. As shown in, the organic film 7 was anisotropically dissolved. As a result, the photoresist 5
Of the exposure light absorber in the organic film 7 to prevent pattern fidelity deterioration (halation) and dimensional accuracy deterioration due to the standing wave effect. I was able to.

Example 2 A novolak resin containing naphthoquinonediazide as a photosensitive group, an exposure light absorber, and TH
An organic film 7 made of a positive resist in which PM and PM were dissolved in xylene was spin-coated on the insulating film 4 to a thickness of about 0.1 μm and baked at 90 ° C. for 2 minutes on a hot plate. Next, a photoresist 5 having the same composition as that used in Example 1 was spin-coated on the organic film 7 to a film thickness of about 0.7 μm, and baked at 80 ° C. for 2 minutes on a hot plate.

Next, after exposing the photoresist 5 and the organic film 7 below it with an exposure device using a KrF excimer laser as a light source, the photoresist 5 is baked at 110 ° C. for 2 minutes so that the photoresist contained in the photoresist 5 is exposed. (4-t-Butylphenyl) iodonium triflate was diffused and permeated into the lower organic film 7. Next, when the photoresist 5 and the organic film 7 were developed with an alkaline developer, the organic film 7 was anisotropically dissolved. As a result, it is possible to prevent the photoresist 5 from collapsing or peeling, and to prevent deterioration of pattern fidelity (halation) and deterioration of dimensional accuracy due to the standing wave effect.

The invention made by the inventor of the present invention has been specifically described above based on the embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

In the above embodiment, the case where a fine photoresist pattern is formed on the semiconductor substrate has been described. However, when the fine photoresist pattern is formed on a substrate for manufacturing a liquid crystal display device, a printed wiring board, or the like. Can also be applied to.

[0018]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

Exposing the photoresist coated on the substrate,
When forming a photoresist pattern by development, an exposure light absorber is contained between the substrate and the photoresist, and an organic film which is anisotropically dissolved when immersed in a developer or water is interposed. This makes it possible to prevent deterioration of pattern fidelity (halation) and deterioration of dimensional accuracy due to the standing wave effect without causing the photoresist to fall or peel.

[Brief description of drawings]

FIG. 1 is a fragmentary cross-sectional view of a semiconductor substrate showing a method for forming a fine pattern according to an embodiment of the present invention.

FIG. 2 is a fragmentary cross-sectional view of a semiconductor substrate showing a method of forming a fine pattern according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a main portion of a semiconductor substrate showing a conventional technique of forming a fine pattern.

[Explanation of symbols]

 1 semiconductor substrate 2 insulating film 3 polycrystalline silicon film 4 insulating film 5 photoresist 6 organic film 7 organic film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03F 7/095 7/11 503 7/26 511 7124-2H 7/38 511 7124-2H H01L 21 / 027 7352-4M H01L 21/30 569 F (72) Inventor Takumi Ueno 1-280 Higashikoigakubo, Kokubunji, Tokyo Metropolitan Research Center, Hitachi, Ltd.

Claims (3)

[Claims] 1. A method for forming a fine pattern, which comprises at least the following steps (a) to (c) in forming a photoresist pattern by exposing and developing a photoresist applied on a substrate. (a) A step of applying an organic film containing an exposure light absorber on a substrate and anisotropically dissolving when immersed in the developer for photoresist used in the step (b), water or an organic solvent. , (B) a step of applying a photoresist on the organic film, and (c) a step of exposing and developing the photoresist to form a photoresist pattern. 2. The organic film is a positive photoresist in which a novolac resin containing naphthoquinonediazide as a photosensitive group is dissolved in a polar solvent, and the photoresist applied on the organic film contains naphthoquinonediazide as a photosensitive group. Novolac resin, THP-M, and bis (4-t
The method for forming a fine pattern according to claim 1, which is a positive photoresist in which -butylphenyl) iodonium triflate is dissolved in a nonpolar solvent. 3. The organic film is a positive photoresist in which a novolak resin containing naphthoquinonediazide as a photosensitive group and THP-M are dissolved in a polar solvent, and the photoresist coated on the organic film is naphtho Novolak resin containing quinonediazide as a photosensitive group, and THP-M
And a bis (4-t-butylphenyl) iodonium triflate dissolved in a non-polar solvent, wherein the positive photoresist is exposed, baked, and then developed. The method for forming a fine pattern according to claim 1.