JPH0342658B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for forming a negative resist pattern during the manufacture of semiconductor devices and the like.

(Prior art) The requirements for higher integration of semiconductor devices have become extremely strict in recent years, and in order to meet these demands, resist patterns are formed using electron beams (EB), etc., and ions, plasma, etc. are used for microfabrication. There is a need for a method of accurately transferring these onto a substrate by dry etching.

By the way, a resist material used for such microfabrication is naturally required to have high resolution and high dry etching resistance.

The inventors first used naphthoquinonediazide sulfonic acid ester (hereinafter referred to as LMR) of novolak resin as a resist material, irradiated the film with a high-energy beam, and developed it with a solution containing acetate ester or alkyl ketone. He proposed a method for forming fine resist patterns with high resolution and excellent dry etching resistance, and achieved great results (Japanese Patent Application No. 19582-1982;
(See Publication No. 146047).

In other words, in this method, a fine rectangular pattern can be obtained by using a high-energy beam such as an electron beam (EB), and a high-resolution pattern with an optimal overhang for lift-off can be obtained by using deep UV light. It was possible to form it. As mentioned above, the developer used in this method was a solution mainly containing acetic acid ester, alkyl ketone, and cyclohexanone.

(Problems to be Solved by the Invention) However, with the above-mentioned developer, if a multilayer resist is used as a base in a multilayer structure, the base resist will dissolve during development, and other problems may occur that hinder good patterning. Problems could not be avoided.

(Means for Solving the Problems) The present inventors have conducted intensive research to solve these problems, and have found that, in patterning using the above-mentioned LMR as a resist, in particular, using LMR as an upper layer and using other photoresists. We have discovered a highly sensitive developing solution that enables good LMR patterning in multilayer resists having the same underlying layer as the underlayer, without damaging the underlying resist in any way.

That is, in the present invention, a film of naphthoquinonediazide sulfonic acid ester of novolac resin is formed on a substrate, a pattern is exposed by selective irradiation with ionizing radiation, and the unexposed areas are developed with a solution containing 50% or more of monochlorobenzene. This is a method for forming a negative resist pattern.

The present invention is characterized in that a monochlorobenzene solution is used as the developer as described above, but a mixed solution with isopropyl alcohol, cyclohexane, etc. may also be used. In this case, it is necessary that the above-mentioned monochlorobenzene be contained at least at 50° C., and if the amount is less than this, the object of the present invention cannot be sufficiently achieved.

(Function) In the present invention, monochlorobenzene in the developer has high sensitivity and high resolution, and also functions to prevent unnecessary damage to the underlying resist.

(Example) The present invention will be specifically described below with reference to Examples.

Example 1 LMR was coated on a Si substrate to a thickness of 0.5 μm, and this was baked at 80° C. for 20 minutes. After that, a pattern was drawn using a 20 KV electron beam at a dose of 30 μc/cm ² , and then a solution of monochlorobenzene and cyclohexane at a volume ratio of 10/2 was used at 23°C.
When developed for 30 seconds, a 0.3 μm line and space negative pattern was resolved.

Example 2 An LMR film was formed on a Si substrate in the same manner as in Example 1, and contact exposure was performed using deep ultraviolet rays at a dose of 40 mJ/cm ² . Thereafter, development was carried out in the same manner as in Example 1, and a 0.5 μm line-and-space negative pattern was obtained. When the cross section of the formed resist was observed using a scanning electron microscope, it was found that a good overhang was formed in the cross section.

The figure shows the sensitivity characteristics of the above developer in the far ultraviolet rays of the above LMR. According to the same figure, the dose amount that gave a 100% residual film rate was 30 mJ/cm ² , which was significantly higher than the conventional developer solution of isoamyl acetate and cyclohexane with a volume ratio of 10/2 shown for comparison. It can be seen that the sensitivity is high.

Example 3 AZ, which is a positive photoresist, was deposited on a Si substrate.
-1350J (manufactured by Shippray) was coated with a thickness of 1.0 μm and baked at 80° C. for 20 minutes. On this resist, LMR dissolved in monochlorobenzene was applied.
After coating to a thickness of 0.5 μm and baking at 80° C. for 20 minutes, contact exposure was performed with far ultraviolet rays at a dose of 40 mJ/cm ² . Thereafter, development was performed at 23° C. for 20 seconds with a mixed solution of monochlorobenzene and isopropyl alcohol at a volume ratio of 10/3.
As a result, the pattern was resolved with lines and spaces of 0.5 μm, and moreover, the AZ−
1350J was completely undamaged.

Example 4 ODUR-, a deep UV resist, was deposited on a Si substrate.
1014 (manufactured by Tokyo Ohka Co., Ltd.) to a thickness of 0.7 μm and baked at 120°C for 20 minutes. Coat LMR on this resist to a thickness of 0.4μm and heat it at 80℃.
After baking for 20 minutes, 30mJ/cm ² with deep ultraviolet rays
Contact exposure was performed at a dose of . After that,
When developed for 20 seconds at 23°C with the same developer as in Example 1, an LMR of 0.5 μm line and space was obtained.
pattern was resolved. The above ODUR of the lower layer −
The 1014th layer was not affected by development at all.

Comparative example AZ- on a Si substrate in exactly the same manner as in Example 3
LMR was further coated on 1350J and exposed in the same manner. Then, when it was developed with a mixture of isoamyl acetate and cyclohexane at a volume ratio of 10/2 at 23°C for 20 seconds, the lower layer AZ-1350J was dissolved.
A good LMR pattern could not be formed.

(Effects of the Invention) As explained above, the present invention provides LMR on a Si substrate.
When a negative resist pattern is obtained by pattern exposure and development using ionizing radiation, remarkable high sensitivity and high resolution are achieved by using a liquid mixture containing 50% or more of monochlorobenzene as a developing solution. It has the advantage that it can be patterned even with resists, and is particularly suitable for use in patterning resists for highly integrated semiconductor devices, and has extremely great industrial value.

[Brief explanation of drawings]

The figure shows the LMR sensitivity curve.

Claims (1)

[Claims] 1 A film made of naphthoquinonediazide sulfonic acid ester of novolac resin is formed on the substrate, a pattern is exposed by selective irradiation with ionizing radiation, and the unexposed areas are developed with a solution containing 50% or more of monochlorobenzene. A method for forming a negative resist pattern.