JPS5983159A - Formation of resist image - Google Patents

Abstract

PURPOSE:To form a resist image having a fine shape and improved resolution by developing a resist made of a polymer contg. aromatic rings or a resist made of a mixture of the polymer with a cross-linking agent using a specified developer. CONSTITUTION:A polymer film made of a polymer contg. aromatic rings or of a mixture of the polymer with a cross-linking agent is formed on a substrate, and it is irradiated with radiant rays such as electron beams, X-rays, ultraviolet rays or deep ultraviolet rays or corpuscular radiation such as ion beams or neutron beams to form a latent image. When the latent image is developed, a soln. contg. dimethylformamide is used as a developer. The developer is suitable for use in the development of a vinylnaphthalene polymer, and it produces a significant effect on a mixture of the polymer with a diazide cross-linking agent. The resist can be thoroughly developed without causing excessive swelling, and a resist image having a fine shape and practically improved resolution can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a resist image, and more particularly to a method for forming a resist image, and more particularly, a method for forming a resist image using radiation such as an electron beam, :Relating to a method for forming a fine resist image to be used.

Conventionally, photolithography technology, in which the entire resist pattern is formed by irradiating light, has been used to manufacture devices that require minute processing, such as integrated circuits and bubble memory devices, but the process accuracy Because there is a limit on the wavelength of
For irradiation with deep ultraviolet rays, X-rays, electron beams, ion beams, etc.↓
It is well known that techniques for forming even finer battens have been developed and are already being put into practical use.

In the early stages of research, photoresist was sometimes used as the resist used to form battens by full irradiation with electron beams, X-rays, deep ultraviolet rays, ultraviolet rays, or ion beams, but in recent years, electron beam Research and development of materials suitable for irradiation with X-rays, deep ultraviolet rays, ultraviolet rays, or ion beams has been carried out at home and abroad, and there are already many publications.

As is well known, there are two types of resist: positive type and negative type. Positive type resists become easily soluble in solvents when irradiated, and are dissolved and removed during development, leaving unirradiated areas behind. It is something that can be done.

In the negative type, the resist in the double irradiation area is difficult to dissolve or insoluble.
The development process changes the remaining double irradiated areas. In other words, when the same drawing board is irradiated, depending on whether the resist is negative or positive, an image of the irradiation button or its inverted image will be obtained, so it is advantageous to use both types of resist depending on the purpose. .

Many materials have been proposed for positive type electron beam resists, including polymethyl methacrylate, polybutene-1-sulfone, and polymethyl isopropenyl ketone, and for negative type materials, polyglycidyl Many materials have been proposed, including methacrylate, copolymers containing glycidyl methacrylate, epoxidized polybutadiene, and polydiallyl phthalate.

In general, positive resists have good resolution or are difficult to obtain with high sensitivity, while negative resists have high sensitivity, but are difficult to obtain if they have poor resolution. However, some of the materials mentioned above are already in practical use, and masks have already been manufactured by electron beam lithography. However, in recent years, dry processes such as ion milling, sputter etching,
Techniques such as flame etching have come to be used to etch resist images onto substrates, and resist materials are now required to have high resistance to these etching methods, that is, dry etching resistance. It has become. Conventionally, resists used mainly for mask manufacturing have been required to have sensitivity, resolution, and etching. For example, in the case of chrome mask manufacturing, resistance to ceric ammonium nitrate aqueous solution is required for wet etching of chromium. Resistance in the dry process was not considered.

As a result of research on the dry etching resistance of resist materials, it has been found that the resistance is significantly improved when a conjugated ring such as a phenyl group is included in the molecule. A is a photoresist
Z resist (trade name, manufactured by Shipley) has good dry etch resistance, but it also contains many phenyl groups.

In addition, polystyrene has been singled out as a typical polymer containing many phenyl groups, and polystyrene dryer.

It has been confirmed that polystyrene, polystyrene U4 (e.g. chloromethylated polystyrene,
Copolymers containing styrene or styrene derivatives have been investigated as resist materials. The inventors also discovered that polyvinylnaphthalene has even stronger dry etch resistance than polystyrene, and found that polyvinylnaphthalene, a polyvinylnaphthalene derivative, or a combination of vinylnaphthalene or a vinylnaphthalene derivative with a monomer that does not contain a naphthalene ring. It has already been proposed to use the polymer as an all-resist. In addition, in order to use these materials as resists and maintain a good resist, the development process, that is, the selection of the developer, is very important. , dichloroethane, etc. are not preferred, and tetrahydrofuran is suitable as a solvent, and it was devised to produce a resist image using tetrahydrofuran or a solution containing tetrahydrofuran.

Tetrahydrofuran is generally used by mixing it with an alcohol-based solvent, but since the mixing ratio differs from the result 1, it is necessary to find the best ratio, and also to keep the ingredients uniform from a storage perspective. It goes without saying that a single solvent is easier to handle. Furthermore, for systems consisting of a polymeric material and a low-molecular crosslinking agent, the developer must be capable of dissolving and removing both of them.

The inventors discovered dimethylformamide as a developing solvent that is suitable for vinylnaphthalene-based polymers and also shows excellent results for mixtures of vinylnaphthalene-based polymers and diazide crosslinking agents. As a result, we have achieved a practically significant invention.

That is, the present invention employs a method for forming a resist image in which a resist made of a polymeric material containing an aromatic ring or a resist made of a mixture of a polymeric material containing an aromatic ring and a crosslinking agent is developed with a developer containing dimethylformamide. In the case of a material in which the aromatic ring is a naphthalene ring, it is particularly preferable, and the complete development process can be carried out without causing the resist to swell significantly, resulting in a resist image with a substantial improvement in resolution and excellent shape. Can be manufactured.

According to the present invention, electron beams, X-rays, ultraviolet rays, deep ultraviolet rays, etc. In the method of producing a resist image by irradiating with radiation or ions or particle beams such as neutron beams to form a replacement image, and then developing, the developer is a solution containing dimethylformamide. A method for forming a characteristic resist image is obtained.

All embodiments of the present invention will be described below.

Example 1 Molecular weight 7.79 million, polydispersity 1.31. Totally synthesized chloromethylstyrene-2vinylnaphthalene copolymer containing 9.1 mol of chloromethylstyrene. After dissolving 5% by weight of this polymer in xylene, it was filtered through a 02 μm filter to obtain a resist solution. Spin coating (200
0 times 7 minutes, 30 seconds) [jp8i No. 8i application, 10
A uniform coating film with a thickness of 0.44 microns was obtained by curing for 0.030 minutes. Using an electron beam exposure device with an accelerating voltage of 20 Kv, various dimensions were obtained with an exposure dose of 2.15 micron/cm2. After drawing the isomorphism of and creating a latent image,
Complete development was carried out by immersing it in dimethylformamide for 60 seconds, followed by rinsing with ethanol for 30 seconds to obtain a resist baton. To this board', heat tighten 160" for 030 minutes (
When the film thickness of the resist button part was measured, it was found to be 0.355 microns, which was 80 mm of the coating film thickness remaining. When the shape of this resist pattern was observed using a full-scanning electron microscope, it was found that a resist pattern with a width of 0.3 microns was completely formed, and its cross-sectional shape was almost rectangular, indicating excellent resolution. was. When benzene, xylene or dioxane was used as a developer, the swelling was severe and it was not possible to form a 1 micron line-and-space pattern.

Example 2 Poly 2-vinylnaphthalene P 2VN (Mw=800
,000゜Mw/Mn=1.5) Ic 4.4'-
5% by weight of diazitohyphenylsul7one was added and dissolved in benzonitrile to make approximately 4% solution 2. This is gold, it's the spin code method! After coating at a speed of 71,500 rpm to form a coating film with a thickness of approximately 2,000 mm, the film was baked at 80"O for 30 minutes.The film thus obtained was coated with electrons. After irradiating the line at 2 μC/Cm2 to completely form a latent image, it was developed with dimethylformamide for 60 seconds and rinsed with ethanol for 30 seconds.
Lines and spaces of 0.8 μm could be resolved.

Example 3 P2VN (Mw=800,000.Mw/Mn=1.
5) 4,4'-Diazidobiphenylsul7-eyed i5
．． was added and dissolved in benzonitrile to make a solution of about 4 g. Using this solution, by spin code method,
A coating film having a thickness of about 2000 angstroms was entirely formed at 1500 revolutions/minute. After baking at 80°C for 30 minutes, heat with a 200W deuterium lamp manufactured by Kouwick Shokai.
After irradiating for 0 seconds to form a latent image, it was developed with dimethylformamide for 90 seconds, and then rinsed with ethanol for 30 seconds, and a 0.8 μm line-and-space pattern was formed.

Example 4 P2VN (Mw=80QOOO, Mw/Mn=1.5)
Ic, 4,4'-diazidobiphenylsulfone 10
After making a benzonitrile solution of about 4% by weight.

The entire coating film was formed in the same manner as in Example 3 and exposed to deep ultraviolet light for '1r.
20+J) and developed with dimethylformamide for 90 seconds and rinsed with ethanol for 30 seconds.
A pattern with good resolution of 8 μm line and space was formed.

According to the present invention, complete development processing can be performed without causing the resist to swell significantly, and a resist image with excellent shape and substantial resolution can be formed.

Claims (5)

[Claims] (1) Radiation such as electron beams, Alternatively, in a method of forming a latent image by irradiating particles m+ with an ion beam or neutron beam, and then forming a resist image by a development process, the resist image is characterized in that the developer is a solution containing dimethylformamide. How to form. (2) The method for forming a resist image according to claim (1), wherein the polymeric material containing an aromatic ring is a polymeric material containing vinylnaphthalene or a derivative thereof as a constituent component. (3) The method for forming a resist image according to claim (2), wherein the polymeric material containing vinylnaphthalene derivatives as a constituent component is chloromethylated polyvinylnaphthalene. (4) The method for forming a resist image according to claim (2), wherein the polymer material containing vinylnaphthalene or a derivative thereof as a constituent component is a copolymer of vinylnaphthalene and chloromethylstyrene. (5) The method for forming a resist image according to claim (1), wherein the polymeric material containing an aromatic ring is polyvinylnaphthalene, and the crosslinking agent is a low-molecular compound having two azide groups.