JPS60196754A - Resist developing solution - Google Patents

Abstract

PURPOSE:To enable a fine resist image to be formed without swelling by incorporating dimethylformamide in a developing soln. for a resist made of a polymer contg. a specified trioxaspiro compd. as structural units. CONSTITUTION:The developing soln. of a resist contg. as structural units a trioxaspiro compd. represented by the formula, n being 1-5, incorporates dimethylformamide. This solvent perfectly dissolves the unexposed parts of the resist without leaving the residue, and moreover, it causes extremely small swelling during the development. The swelling can be more suppressed by mixing a poor solvent, such as propylene glycol, with such a soln., and using this mixture, thus permitting a resist image good in resolution to be formed and used for semiconductor integrated circuits, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a developer used in a resist image forming method;
More specifically, the present invention relates to a developer used in a resist image forming method using an electron beam or x, *'4.

[Problems with conventional technology]

Conventionally, in the manufacture of semiconductor devices, a process of coating a photosensitive resin (photoresist) on a substrate, forming a fine pattern by exposing and developing it, and then wet-etching the parts not covered by the resist pattern. He used the law. However, this method has a limited resolution of approximately 1 micron due to light diffraction, and mixed etching is not suitable for microfabrication of 1 micron or less due to side etching and the effects of etchant impurities. do not have.

Recently, with the demand for higher density semiconductor integrated circuits, plasma etching has been replaced by wet etching by forming fine patterns using radiation such as X-rays and electron beams, which have even shorter wavelengths than light. Dry etching methods using gas, reactive sputtering, ion milling, etc. are now becoming mainstream methods for forming highly accurate fine patterns.

Therefore, the resist used in such a microfabrication method is required to have not only high sensitivity to radiation but also high resistance to plasma gas, reactive sputtering, and ion milling.

The present inventor has already proposed a resist material containing a trioxaspiro compound represented by the general formula (nFi, representing an integer from 1 to 5) as a constituent element, which enables the formation of a high-sensitivity and good resist image. I showed what I can do.

However, compounds containing trioxaspiro compounds as constituents are mainly composed of commonly used solutions of ketones such as tethohydrolanomethylethylketone and methylisobutylketone, and solutions of esters such as methylethyl acetate and celso μ-deacetate. A developing solution containing the above had the disadvantage that it swelled rapidly during development, making it difficult to form a fine resist image.

[Purpose of the invention]

The present invention aims to improve these drawbacks and provide a developer that does not cause swelling and is capable of forming fine resist materials.

[Korea of invention]

The present inventor investigated various solvents as a developer for a resist material containing a trioxaspiro compound as a component, and found that a developer containing dimethylformamide was particularly excellent.

[Structure of the invention]

The present invention relates to a resist developer comprising a polymer containing a trioxaspiro compound represented by the general formula (where n represents an integer from 1 to 5) as a constituent, which contains dimethylformamide. It is a developer.

[Detailed explanation of configuration]

That is, the developer of the present invention applies an electron beam to a resist made of a polymer containing a trioxaspiro compound as a component.
This method uses a method in which a resist image is formed by irradiating the resist with X-rays, etc. to make it insolubilized, and then dissolving and removing the unirradiated areas.
It consists of a solution containing dimethylformamide.

After comparing various solvents, we found that dimethylformamide dissolves the unirradiated areas very well without leaving any residue. Moreover, it was found that the swelling during development was extremely small. Therefore, when developed with a solution containing dimethylformamide as a main component, a fine resist image can be formed without leaving any residue. Although dimethylformamide may be used alone, swelling can be further suppressed by mixing with a poor solvent.

Examples of the poor solvent to be mixed include isoglobil alcohol and ethyl alcohol. If necessary, after processing with a developer, it may be rinsed with a poor solvent. In the developing solution, it is desirable that the zero proportion of dimethylformamide is equal to or greater than the added volume %. If it is less than this, the solubility will not be sufficient and the unirradiated portion will not be completely dissolved.

〔Example〕

The present invention will be explained below using Examples.

(Example 1.) Acrylonitri/l//)rioxaspiro compound (n
=5) =80/20 Average weight molecular weight 70,000
A copolymer having a dispersity of 2.2 was dissolved in benzonitrile to obtain a 15% by weight resist solution. The obtained resist solution was also applied by spin coating (2000 rotations/rotation button) and baked at 801'C for 80 minutes to obtain a uniform coating film with a thickness of 0.6 micrometers. Acceleration voltage GOICV.

After forming a latent image by drawing patterns of various dimensions with a radiation dose of 1Oμc/d, it was developed for 90 seconds with a mixed solvent of dimethyμformamide:isoderopyl alcohol lva:i.

When the obtained resist image was observed, a resist pattern with a width of 0.8 microns was formed, indicating excellent resolution.

(Reference Example) For comparison with the present invention, a conventional example similar to Example 1 was prepared using tetrahydrofuran:isoderopiμalco-/L'
When developed for 90 seconds with a mixed solvent of 8:l, a resist image with a width of 2 capes was formed, but no higher resolution was achieved. In addition, residues were present in some places.

(Example 2) The same resist solution used in Example 1 was applied by spin coating (6000 times for 1 minute) and baked at 80°C for 80 minutes to form a uniform coating film with a thickness of 0.48 microns. Obtained. After exposure with an accelerating voltage of 20 KV and a irradiation dose of 2011c/eJ, it was exposed with dimethylformamide for 90 seconds (1, rinsed with Ingropyl alcohol μ for 80 seconds. Iil measurement showed that a resist image with a width of 0.6 microns was well formed. It was done.

(Example 8.) Acrylonitrile/L//trispirooμso compound (n
= 8) = 56/44 average weight molecular weight 110,0
A copolymer having a 0.00 dispersity of 2.8 was dissolved in benl nitrile to form a 15% by weight resist solution. This resist solution was spin-coated (at 8000 revolutions/min) to form a coating film of 0.5 micron. Acceleration voltage 20KV, 12μ
The film was exposed to light at a dose of c/d, developed for 90 seconds with a mixed solution of dimethic μformamide:isopropyl alcohol/L'l:l, and then rinsed with isoglobin μ alcohol for 80 seconds.

As a result of observation, a resist image with a width of 0.8 microns was well formed, showing excellent resolution.

〔Effect of the invention〕

As described above, the present invention has the effect of greatly reducing swelling during development of a resist containing the dimethylformamide xaspiro compound as a component and forming a resist image with good resolution.

Patent applicant: NEC Corporation

Claims (1)

[Claims] (1) A resist developer comprising a polymer containing a trioxaspiro compound represented by the general formula (where n represents an integer from 1 to 5) as a constituent, characterized by containing dimethylformamide. Resist developer 0