JPS60196755A - 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 trioxabicyclo compd. as structural units. CONSTITUTION:The developing soln. of a resist contg. as structural units a trioxabicyclo compd. represented by the formula, R being alkyl, 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 electron beams or X-rays.

[Prior art]

Conventionally, in the manufacture of semiconductor devices, a photosensitive resin (PhotoL/Syst) is applied onto a substrate, exposed and developed to form a fine pattern, and the areas not covered by the resist pattern are wet-etched. A processing method was used. However, this method has a limited resolution of approximately 1 micron due to light diffraction, and KM etching is not suitable for microfabrication of 1 micron or less due to side etching and the effects of etchant impurities. .

Recently, with the demand for higher densification of semiconductor integrated circuits, fine patterns have been formed using radiation such as X-rays and electron beams with shorter wavelengths instead of light, and plasma gas and Dry etching methods such as reactive sputtering and ion milling are becoming mainstream to form highly accurate fine patterns.

Therefore, resists used in such microfabrication methods are required to have high sensitivity to radiation as well as high resistance to plasma gas reactive sputtering and ion milling.

The present inventor has already proposed a resist material containing a trioxabicyclo compound represented by the general formula as a constituent, and has shown that it is possible to form a highly sensitive and good resist image.

However, compounds containing a trioxabicyclo compound as a constituent are the commonly used tetraxabicyclo compound.
Developers containing solutions of ketones such as ethyl ketone and methyl isobutyl ketone, and solutions of esters such as methyl ethyl acetate and 7-solp acetate as main components cause severe swelling during development, making it difficult to form fine resist images. There was a drawback.

[Purpose of the invention]

The present invention improves these drawbacks and provides a developer that is free from swelling and capable of forming fine resist images.

The inventor investigated various solvents as a developer for a resist material containing a trioxabicyclo compound as a component, and found that a developer containing dimethylformamide was particularly excellent, and thus arrived at the present invention.

[Structure of the Invention] The present invention is a resist developer comprising a polymer containing a trioxabicyclo compound represented by the general formula as a constituent, which is characterized by containing dimethylformamide.

[Detailed explanation of configuration]

The developer of the present invention irradiates a resist made of a polymer containing a trioxabicyclo compound as a component with electron beams, X-rays, etc. to make it insolubilized, and then dissolves and removes the unirradiated portions to form a resist image. method and 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 isopropyl alcohol and ethyl alcohol. If necessary, after processing with a developer, rinsing may be performed with a poor solvent. In the developer, the proportion of dimethylformamide is desirably 20% by volume or more. 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.) Acrylonitrile/L//trioxabicyclo compound (R
=C21h) = 80/20 average weight molecular weight 8
A copolymer having a dispersity of 2.8 was dissolved in pengnitrile to obtain a 16% by weight resist solution. The obtained resist solution was applied by spin coating (gooo rotations/min) and baked at 800°C for 80 minutes.
A uniform coating film with a thickness of J3 microns was obtained. Acceleration voltage 20KV
After forming a latent image by drawing patterns of various dimensions with an irradiation dose of 10 μc/ej, it was developed for 90 seconds with a mixed solvent of dimethyl formamide:isoprobil acetate/l/8:l.

Observation of the resulting resist image revealed that a resist pattern with a width of 0.8 microns was formed and exhibited excellent resolution.

(Reference Example) For comparison with the present invention, a conventional example similar to Example 1 was prepared using tetofhydrofuran:isopropyl alcohol/L'
When developed in a 3:l mixed solvent for a few seconds, a resist image two doors wide was formed, but no higher resolution was achieved.

In addition, residues were present in some places.

(Example 2.) Example 1. The same resist solution as that used in was applied by spin coating (6000 times for 1 minute) and baked at 80° C. for 80 minutes to obtain a uniform coating film with a thickness of 0.48 microns. After exposure at an accelerating voltage of IKV and a dose of goμc/14, the film was developed with dimethylformamide for 90 seconds and rinsed with Ingropyraμco for 80 seconds.

As a result of observation, a resist image with a width of 0.6 microns was successfully formed.

(Example 8.) Acrylonitrile IL//trioxabinclo compound (R
= CHa ) = 62/88 average weight molecular weight igo,
A copolymer having a dispersity of 2.4 was dissolved in benzonitrile to obtain a 14% by weight resist solution. This resist solution was applied by spin coating (8000 revolutions/min) to
A micron coating film was formed. Acceleration voltage 20KV, 12
The film was exposed to light at a dose of μc/d, developed for 90 seconds with a mixed solution of dimethylhopamide:isoderopyl alcohol/I/1:l, and then rinsed with isopropyl alcohol for 80 seconds.

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

〔Effect of the invention〕

As described above, if the developer of the present invention containing dimethymu-formamide is used, the swelling during development of the resist containing the trioxabicyclo compound as a component can be extremely reduced, resulting in fine resist images with good resolution. It has the effect of being able to form.

Patent applicant: NEC Corporation

Claims (1)

[Scope of Claims] (l) - A resist developer comprising a polymer containing a trioxabicyclo compound represented by the general formula % as a constituent, characterized in that it contains dimethyμhopamide. developer solution.