JPS60130829A - Formation of resist pattern - Google Patents

Abstract

PURPOSE:To enable to form submicron resist patterns in thick film, simply and easily by performing a developing only by a method wherein an exposure is performed with ultraviolet rays of a specific wavelength using a coated film of quinone diazide sulphonate. CONSTITUTION:A coated film 2 of quinone diazide sulphonate is adhered on the surface of a substrate 1 and a selective exposure is performed on only regions, wherein the coated film 2 should be remained as a resist pattern, with far ultraviolet rays L1 of 200-300nm through masks 3 for forming far ultraviolet ray irradiation regions 2a. The masks 3 are removed, a mask 4 is respectively adhered on the regions 2a, an exposure is selectively performed with ultraviolet rays L2 of a wavelength longer than 300nm and ultraviolet ray irradiation regions 2b are formed. A developing is performed on the resist coated film 2 and resist patterns 5 in an overhanging configuration are obtained. As a result, microscopic resist patterns, whose sectional configurations are suitable for processing by a lift-off technique, can be easily formed by performing a developing only.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for forming a resist I pattern for patterning a deposited layer of metal, insulator, etc. by lift-off during the manufacture of semiconductor devices and the like.

(Description of Prior Art) When manufacturing semiconductor devices and the like, there are two conventionally known methods for forming patterns on deposited layers of metals, insulators, etc.: an etching method and a lift-off method. The lift-off method is a simple method, is suitable for forming fine patterns without causing damage due to etching, and has the advantage that even metals that are difficult to etch can be easily patterned. However, the lift-off method requires strict conditions regarding the cross-sectional shape, heat resistance, solubility, adhesion, etc. of the resist film. for example,
In order to easily form a pattern by lift-off, it is necessary that the adhered layer on the resist film can be easily removed as the resist dissolves, and for this purpose, the cross-sectional shape of the patterned resist film must be must have an overhang shape. In addition, in order to improve the radical youthfulness of metals, etc., it is effective to heat the substrate during vapor deposition, so it is required that the resist has good heat resistance. Before and during vapor deposition, it is required that the resist has good adhesion to the substrate so that the resist layer does not peel off.
In order to form highly integrated fine patterns such as VLSI, the resist I is required to have high resolution.

By the way, at present, in order to form this overhang feature, a multilayer structure is used or a positive photoresist, for example, chlorobenzene treatment of AZ-1350J (trade name of a photoresist manufactured by Shipley) is used. These processes are complicated, have poor throughput, do not necessarily have good reproducibility, and are difficult to obtain submicron resolution.

(Object of the Invention) In view of the above-mentioned conventional drawbacks, an object of the present invention is to form a resist film forming a resist pattern into an overhang cross-sectional shape by only development, and to form a resist pattern with a thickness of submicron. An object of the present invention is to provide a method for forming a pattern of a lift-off resist, which allows simple and easy pattern formation of a film.

Furthermore, another object of the present invention is to provide excellent throughput;
An object of the present invention is to provide a method for forming a pattern of a lift-off resist with good reproducibility.

(Structure of the Invention) In order to achieve this object, according to the present invention, the skin 11 of quinone diazide sulfonic acid ester is used as a resist film, and the area of the resist film 11 to be left as a resist pattern is 200 to 300 ntn. Selectively expose to deep ultraviolet rays to remove 30 areas of resist peeling.
The gist is to expose to ultraviolet light with a longer wavelength than On+*.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A to 1C are process diagrams for explaining the resist pattern forming method of the present invention.

First, before explaining the method of the present invention, the resist material used in the present invention will be explained.

In order to solve the conventional drawbacks of the lift-off method, the inventors of this invention found that the cross-sectional shape of the resist pattern was made into an open shape based on the results of numerous experiments. I found it suitable.

Moreover, this material is soluble in the developer, but when this resist material is irradiated with ultraviolet rays, the solubility of the resist in the developer increases by about 5 times in the UV irradiated areas compared to the non-UV irradiated areas. It was found that the solubility of the compound in organic solvents was also very good. Furthermore, it has been found that when this resist material is irradiated with deep ultraviolet rays, only the vicinity of the surface layer of the resist film through which the far ultraviolet rays have passed becomes insoluble in the developer.

Furthermore, since this material has excellent heat resistance, it has been found that by heating the substrate during application of the adhesion layer, the adhesion of the resist and the adhesion layer to the substrate increases by one.

Therefore, in the method of the present invention, a resist pattern is formed by utilizing the property that when this resist is irradiated with ultraviolet rays or far ultraviolet rays, the solubility of the resist in a developer changes or becomes insolubilized. It is something.

That is, according to the present invention, quinonediazide sulfonic acid ester is used as the resist material (1)! As shown in FIG. 1(^), a film 2 of quinonediazide sulfonic acid ester is formed on the surface of a substrate 1. Next, after forming a mask 3 on this resist film +122'J-, selective irradiation with deep ultraviolet rays L1 is performed through this mask 3 only on the area where the resist film 2 is to remain as a resist pattern. The area irradiated with this far ultraviolet ray Ll is indicated by 28.

Next, as shown in FIG. The surface portion of the resist film 2 is exposed and exposed to ultraviolet light L2.
irradiate. This ultraviolet irradiation area is indicated by 2b, and
The area not irradiated with far ultraviolet rays L] and ultraviolet rays L2 is indicated by 2c.

Next, this resist film 2 is developed, and as shown in FIG.
), a resist pattern 5 having an overhanging cross section is obtained. In this case, the ultraviolet irradiation area 2b has about five times the solubility in the developer as compared to the non-irradiation area 2c, and the far ultraviolet irradiation area 2a does not dissolve in the developer, so this resist i/film cannot be developed. Accordingly, area 2
C is completely removed, region 2c is slightly dissolved, and region 2c is completely removed.
A is hardly dissolved, so that an overhang-shaped resist pattern 5 as shown in FIG. 1(C) is obtained.

Next, specific examples and comparative examples of the resist pattern forming method according to the present invention will be described.

Note that the embodiments described here are within the scope of this invention.
These examples are merely examples under specific conditions, and it is clear that the present invention is not limited only to these examples.

Examples A naphthoquinone-1,2-diazide-5-sulfonic acid ester (hereinafter referred to as LMR) of a novolak resin, which is a type of quinonediazide sulfonic acid ester of a novolak resin, was used as a resist material. in this case,
Considering that a low degree of polymerization is one of the reasons for improving resolution, a naphthoquinone-1,2-diazide-5-sulfonic acid ester of a novolac resin having a degree of polymerization of 1 to 10 was used.

First, this LMR was dissolved in methylcellosolve acetate and coated on a silicon substrate to a thickness of 2 cm.
A resist film 2 was formed. Next, after heat-treating (pre-baking) the substrate l having the resist film M2 at a temperature of 60°C for 30 minutes, this resist film 2 is
Hg wrap: 200-300 nm 17) Exposure was selectively performed with far ultraviolet light L1 for 5 seconds through a mask 3 to form a far ultraviolet irradiation region 2a.

Next, after removing this mask 3, an inverted mask 4 of this mask 3 is applied, and ultra-high pressure H is applied through this mask 4.
Selective exposure is performed for 60 seconds with ultraviolet light L2 with a wavelength longer than 300 nm from the g lamp, and the ultraviolet irradiation area 2b is
I got it. In this case, the solubility of the ultraviolet ray irradiation area 2b in the developer improves with the irradiation amount of the ultraviolet ray L2;
This ultraviolet irradiation effect appears after a few seconds of irradiation and becomes saturated in about 60 seconds.

Even when irradiated for long periods of time, such as 5 minutes and 10 minutes, the dissolution rate was almost the same as that obtained when irradiated for 60 seconds, and no effects or adverse effects of long-term irradiation appeared.

Next, this sample was heat-treated at a temperature of +oo'c for 30 minutes, and the next iteration was performed on the corresist skin 112 (2a, 2b, 2c).
) was developed for 60 seconds at a solution temperature of 23° C. using a solution in which water was saturated with 10 parts of isoamyl acetate to 5 parts of cyclohexane in a volume ratio.

When the results were observed using a scanning electronic LLI microscope, it was confirmed that a resist pattern 5 with an overhang cross section as shown in FIG. It was confirmed that a line and space of 0.5 and a line of 0.5 end were obtained.

Next, on the substrate surface including this resist pattern, for example, N is vacuum-deposited to a thickness of 1.5 layers /AirL,
After forming an adhesion layer using , the sample was immersed in an organic solvent such as an acetone solution to perform lift-off. When the results were observed with a scanning electron microscope, it was confirmed that the lift-off was completed completely, and a line and space of 0.5 gm and a line of 0.5 gm were obtained.

Comparative Example A resist film similar to that of the above-mentioned example was exposed to ultraviolet rays from a 500W Xe-Hg lamp without being irradiated with ultraviolet rays using the ultra-high-pressure Hg lamp in this example.
selectively exposed to 300 nm deep ultraviolet Ll for 5 seconds through a mask, and then
After heat treatment was performed at a temperature of 00° C. for 30 minutes, development was performed with a solution in which cyclohexane 2 was saturated with water in a volume ratio of isoamyl acetate IO to isoamyl acetate IO.

When the results were observed with a scanning electron microscope, it was found that 1.5
It turned out that the lines and spaces of the pot ys could be obtained, but the resolution on the order of submicrons, i.e. 0.5
It was confirmed that line and space of pmaro and Igm could not be obtained.

(Effects of the Invention) As is clear from the above, according to the method for forming a resist pattern according to the present invention, a quinonediazide sulfonic acid ester film is used as the resist I film,
The part of the resist that is to remain is exposed to deep ultraviolet light, and then the reverse pattern is exposed to ultraviolet light using a one-inversion pattern, so that only development is required to produce submicron particles with an overhang cross-sectional shape that is suitable for lift-off. The advantage is that a fine resist pattern can be formed in a thick film simply and easily by cooling.

Further, according to the present invention, after the resist film 11 is deposited, it is possible to perform selective exposure with far ultraviolet rays and ultraviolet rays in mutually inverted patterns, and then perform development processing. According to the method described above, the processing is simple, the throughput is excellent, and the compatibility is also good.

Furthermore, since this resist material has excellent heat resistance, there is an advantage that the adhesion of the resist and the adhering layer to the substrate can be improved by heating the substrate during adhesion and adhesion of the layer.

The pattern forming method of the present invention is to make the resist insoluble (negative) in a developer by selective irradiation with far ultraviolet rays, to accelerate the dissolution rate by irradiating ultraviolet rays, and to reduce the light absorption of the resist in the wavelength region of far ultraviolet rays. is large Regis I
・Light only passes through the vicinity of the surface layer, and
This method takes advantage of the phenomenon that in the ultraviolet wavelength range, light can penetrate and reach the substrate surface even if the film is thick, so the method of this invention can be applied to any resist that satisfies this requirement, and is similar to the method described above. It is clear that excellent effects can be achieved.

The resist pattern forming method of the present invention is suitable for use in manufacturing semiconductor devices, magnetic bubble elements 1 surface acoustic wave devices, and the like.

[Brief explanation of the drawing]

FIGS. 1A to 1C are process diagrams for explaining the resist pattern forming method of the present invention, and are schematic cross-sectional views showing the state of a sample at main process steps. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Resist film 2a...Deep ultraviolet ray irradiation area 2b...Ultraviolet irradiation area 2c...Unirradiated area of resist film 19 3...Mask 4 . . . Reversal of mask 3 Mask 5 . . . Resist pattern Ll (with an overhanging cross section)... Far ultraviolet rays, L2 ... Ultraviolet rays. Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] JIA 200-300 of quinonediacid sulfonic acid ester formed as a resist film on the substrate surface
The method is characterized by comprising a step of selectively exposing to ultraviolet rays with a wavelength longer than 30'0 nm, and a step of exposing all of the unexposed portions of the resist film that have not been selectively exposed to the far ultraviolet rays with ultraviolet rays having a wavelength longer than 30'0 nm. How to form a resist pattern.