JPH0160816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a resist image, and more particularly, to a method for producing a resist image using electron beams, X-rays, ultraviolet rays, or
The present invention relates to a method for producing a fine resist image using radiation such as the following deep violet radiation or a particle beam such as an ion beam or a neutron beam.

Conventionally, photolithography technology, which forms a resist pattern by irradiating light, has been used to manufacture devices that require minute processing, such as integrated circuits and bubble memory devices. It is well known that, because of the limitations on the wavelength order, techniques for forming even finer patterns by irradiation with deep ultraviolet rays, X-rays, electron beams, ion beams, etc. have been developed and are already being put into practical use.

In the early stages of research, photoresists were sometimes used as resists for pattern formation by irradiating 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 is being 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 processing, resulting in a pattern with unirradiated areas remaining. It is something that can be done. In the negative type, the resist in the irradiated area becomes poorly soluble or insoluble, and a pattern in which the irradiated area remains is obtained by development. In other words, when the same pattern is irradiated, an image of the irradiation pattern or its inverse image can be obtained depending on whether the resist is negative or positive, and both types of resist can be used depending on the purpose. That is advantageous.

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

In general, positive resists have excellent resolution but are difficult to obtain with high sensitivity, while negative resists are easy to obtain with high sensitivity but have difficulty in 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 have become more
i.e. ion milling, sputter etching,
As techniques such as plasma etching are used to etch resist images onto substrates, resist materials are required to have high resistance to these etching methods, that is, dry etching resistance. I'm getting used to it. Conventionally, resists used primarily for mask manufacturing have been required to have sensitivity, resolution, and etching resistance. For example, for chrome mask manufacturing, resists have been required to have resistance to ceric ammonium nitrate aqueous solution for wet etching of chromium, and dry etching has been required. Resistance in the 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. AZ resist, a photoresist (Shitsupray Co., Ltd.,
(trade name) has good dry etch resistance, but it also contains many phenyl groups. In addition, polystyrene has been taken up as a typical polymer containing many phenyl groups, and it has been confirmed that polystyrene has good dry etch resistance.
Polystyrene derivatives (eg, chloromethylated polystyrene, polychlorostyrene) and 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 copolymerization of polyvinylnaphthalene, polyvinylnaphthalene derivatives, or vinylnaphthalene or vinylnaphthalene derivatives with monomers that do not contain a naphthalene ring We have already proposed using objects as resists. In addition, in order to obtain a good resist image using these materials as a resist, the development process, that is, the selection of the developer, is very important.
The inventors have already discovered that benzene, xylene, chlorobenzene, dichloroethane, etc. are not preferable for styrene-based resists, and that tetrahydrofuran is suitable as a solvent, and they have proposed that a resist image can be manufactured using tetrahydrofuran or a solution containing tetrahydrofuran. Proposed.

Tetrahydrofuran is generally used by mixing it with an alcohol-based poor solvent, but since the results vary depending on the mixing ratio, it is necessary to find the best ratio and to keep the components uniform from a storage perspective. Needless to say, it is easier to handle.

The inventor conducted further research and found chlorobenzene, which was not necessarily suitable for styrene-based resists, as a developing solvent that was suitable for vinylnaphthalene-based polymers and also showed excellent results even with a single composition. By discovering chlorine-containing solvents such as 1,2-dichloroethane, trichlorethylene, and tetrachlorethylene, the present invention, which is of practical significance, was achieved.

That is, the present invention provides a method for producing a resist image, in which a resist made of a polymeric material containing naphthalene rings is developed with a developer containing a chlorine-containing solvent. According to the present invention, a complete development process can be performed without causing the resist to swell significantly, and a resist image with substantially improved resolution and excellent shape can be produced.

The invention will be explained in detail below using examples.

Example 1 Chlormethylstyrene with a molecular weight of 779,000, a polydispersity of 1.31, and a chloromethylstyrene content of 9.1 mol% ~
2-vinylnaphthalene copolymer was synthesized. After dissolving 5% by weight of this polymer in xylene, 0.2μm
The resist solution was obtained by passing it through a filter. It was applied onto a Si substrate by spin coating (2000 rpm, 30 seconds) and hardened at 100°C for 30 minutes to obtain a uniform coating film with a thickness of 0.44 microns. Using an electron beam exposure device with an accelerating voltage of 20KV, 2.15 microcoulombs/
After creating a latent image by drawing figures of various dimensions with an exposure dose of cm ² , it was developed by immersing it in tetrachloroethylene for 60 seconds, followed by methyl ethyl ketone 1
Volume: A resist pattern was obtained by rinsing for 30 seconds with a mixed solution of 1 volume of ethanol. This board is heated to 160℃.
After 30 minutes of hardening (post-bake), the film thickness of the resist pattern area was measured and found to be 0.355 microns, with 80% of the coating film remaining. When the shape of this resist pattern was observed using a 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. .
When benzene, xylene, or dioxane was used as a developer, the swelling was so severe that even a 1 micron line-and-space pattern could not be formed.

Example 2 Experiments and evaluations were conducted in the same manner as in Example 1, using trichlorethylene instead of tetrachlorethylene in the developing solution in Example 1. Similar good results were obtained using trichlorethylene.

Example 3 Similar experiments and evaluations were conducted using carbon tetrachloride instead of the developer tetrachlorethylene in Example 1. Similar good results were obtained, but the development time was longer than 300 seconds.

Example 4 Almost the same good results were obtained by using 1,2-dichloroethane in place of the developer tetrachloroethylene in Example 1.

Example 5 Almost the same good results were obtained by using chlorobenzene in place of the developer tetrachloroethylene in Example 1.

Examples 6 to 10 Chlormethylstyrene with a molecular weight of 171,000, polydispersity of 2.67, and a chloromethylstyrene content of 25 mol% ~2
A vinylnaphthalene copolymer was produced, dissolved in xylene at 5% by weight, and passed through a 0.2 micron filter to prepare a resist solution. However, the appropriate coating film thickness was 0.22 microns by spin coating (2000 revolutions/minute, 30 seconds) and the appropriate exposure dose was 6.0 microcoulombs/cm ² .

The developing solutions used in Examples 1 to 5, namely, tetrachloroethylene, trichloroethylene, carbon tetrachloride, 1,2-dichloroethane, and chlorobenzene, all showed the same good results as Examples 1 to 5.

Examples 11 to 13 Poly2-vinylnaphthalene having a molecular weight of 809,000 and a polydispersity of 1.47 was evaluated in the same manner as described in Example 1. However, the exposure amount is 17.0 microcoulombs/
^cm2 was appropriate. As the developer, tetrachlorethylene, trichloroethylene, and 1,2-dichloroethane were used, and the same good results as in Example 1 were obtained in all cases.

Examples 14 to 18 Chloromethylated poly-2-vinylnaphthalene having a molecular weight of 51,000, a polydispersity of 3.0, and a chloromethylation rate of 10.5% was produced by chloromethylation of poly-2-vinylnaphthalene. This material was evaluated in the same manner as described in Example 1. However, the appropriate coating thickness was 0.22 microns by spin coating (1000 revolutions/minute, 60 seconds), and the appropriate exposure dose was 25 microcoulombs/cm ² .

The developing solutions used in Examples 1 to 15, ie, tetrachloroethylene, trichloroethylene, carbon tetrachloride, 1,2-dichloroethane, and chlorobenzene, all showed good results.

As described above in detail, a solvent having chlorine in its molecule is extremely excellent as a developing solvent for a resist material having a naphthalene ring in its molecule.

Optimal development conditions (solvent, time, etc.) vary depending on the material. In general, the higher the molecular weight of the resist polymer, the more desirable the solvent is to have strong dissolving power, and as the content of chloromethyl groups in the polymer increases, the solubility tends to increase. It is determined from Solvents containing chlorine are suitable for resists containing naphthalene rings. In addition to tetrachloroethylene, trichloroethylene, carbon tetrachloride, 1,2-dichloroethane, and chlorobenzene mentioned in the examples, many solvents such as dichlorobenzene, chloroform, chlorobutadiene, chloropropylene, and chloramyl can be used. As a developer, it is desirable that it is easily available and inexpensive, and chloride is more desirable than bromide.

As mentioned earlier, the optimal developing solvent may be a single composition of these solvents, a mixture of the solvents listed, or, if weaker solvent power is desired, a naphthalene ring. It is also possible to use alcohols, etc., which are non-solvents, mixed with the polymer containing .

Claims (1)

[Claims] 1. A polymer film formed on a substrate and made of a polymer material containing vinylnaphthalene or its derivatives as a component is exposed to radiation such as electron beams, X-rays, ultraviolet rays or deep ultraviolet rays, or ion beams or neutrons. A method of producing a resist image by forming a latent image by irradiating it with a particle beam such as a beam, and then performing a development process, the resist being characterized in that the developer is a solution containing a chlorine-containing solvent. How to make statues. 2. The manufacturing method according to claim 1, wherein the polymer containing vinylnaphthalene or a derivative thereof as a constituent component is chloromethylated polyvinylnaphthalene. 3. The manufacturing method according to claim 1, wherein the polymer containing vinylnaphthalene or a derivative thereof as a constituent component is a copolymer of vinylnaphthalene and chloromethylstyrene. 4. The manufacturing method according to claim 1, wherein the chlorine-containing solvent is chlorobenzene, dichlorobenzene, 1,2-dichloroethane, trichloroethylene, tetrachloroethylene, or carbon tetrachloride.