JPS6237932A - Resist-pattern forming method - Google Patents

Abstract

PURPOSE:To form a very minute resist pattern, by forming a specified resist pattern having a specified shape on a substrate, projecting plasma including F or Cl, etching the resist with O2 gas in an anisotropic method, and thereafter immersing the pattern in an organic solution. CONSTITUTION:A resist pattern 2 is formed on a semiconductor substrate 1. Plasma is projected on the resist pattern 2 by using a cylindrical plasma etching device and a gas comprising C2HCl3/5% O2 at 0.4Torr for 1min at plasma generating power of 15W. Then, by using a reactive ion etching device, etching is performed with O2 gas, and the surface of the resist pattern 2 is removed by 0.1mum or more in an anisotropic mode. During this period, the etching is performed for 1min under the conditions of pressure of 15mTorr, RF power of 175W and O2 gas flow rate of 40secM. Finally the pattern is immersed (5) in isoamyl acetate for 10sec, and a very minute resist pattern 4, whose pattern width is 0.1mum, is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for forming ultra-fine resist patterns.

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2. Description of the Related Art As the demand for miniaturization of semiconductor devices increases, photolithography technology for forming fine patterns has become important. Photolithography technology includes processing steps such as photoexposure of resist, electron beam exposure, and X-ray exposure. Among these, light exposure is usually due to the influence of light diffraction.
It is not possible to form fine patterns of 0.5 μm or less. On the other hand, electron beam exposure and X-ray exposure are capable of forming fine patterns of 0.5 μm or less, but have the drawbacks of high equipment cost and low throughput.

Problems to be Solved by the Invention As stated above, when forming fine patterns of 0.6 μm or less, it was necessary to use electron beam exposure equipment or X-ray exposure equipment that is expensive and has low throughput. .

The present invention solves the above problems and uses light exposure to
The present invention provides a method for forming fine patterns of micrometers or less.

Means for Solving the Problems The present invention involves forming a resist pattern of a predetermined shape on a substrate, isotropically irradiating the resist pattern with plasma containing F4 or Cl, and then performing a reaction using 02 gas. This resist pattern forming method includes the steps of anisotropically etching the resist to a predetermined thickness using polar ion etching, and then immersing it in an organic solvent.

Function According to the present invention, the surface layer of the resist pattern is F-i
It is isotropically hardened and altered by irradiation with plasma containing C4 or C4, and then reactive ion etching
By anisotropically etching the same surface layer, it is possible to leave only the hardened and altered portions on the sides of the resist pattern, and thus, using the resist pattern formed by light exposure, the width corresponding to the thickness of the hardened and altered portions can be approximately 0.5 μm
The following ultra-fine patterns can be formed.

Embodiments Below, embodiments of the present invention will be described with reference to the drawings. First, a resist pattern 2 is formed on the semiconductor substrate &1. The resist pattern 2 can be formed, for example, through the following steps. A photoresist (manufactured by Tokyo Ohka Chemical Co., Ltd.) OFPR8oO is applied onto the substrate to a thickness of 1.2 μm, and prebaked at 86° C. for 20 minutes. Next, using a reduction projection exposure means, a so-called stepper, 100 mJ
Exposure was carried out at
Resist pattern 2 can be formed by developing for 1 minute using D-3. Then, as shown in FIG. 1a, the cyst pattern 2 was etched using a cylindrical plasma etching device using a gas of 15% C2HCl3 at 0.4 Torr and a plasma generation power of 15%.
Perform plasma irradiation with W for 1 minute. This plasma irradiation is performed for the purpose of hardening and altering the resist surface. next,
As shown in FIG. 2, etching is performed using O2 gas using a reactive ion etching apparatus to remove 0.1 μm or more of the surface of the resist pattern 2 anisotropically.

This process requires a pressure of 15 mTorr and an RF power of 5
Etching was performed for 1 minute under the conditions of 175W and 02 gas flow rate of 40 sccM. Finally, by immersing it in inamyl acetate for 10 seconds, the pattern width shown in Figure 1C is reduced to 0.
．． A fine resist pattern 4 of 1 μm can be formed.

In the above examples, the product name 0FPR manufactured by Tokyo Ohka Co., Ltd.
Although a positive photoresist made of a diazo novolak resin known as 800 has been described, patterns can be formed in the same manner with other resists. CF415 instead of C2HCl3102
The same effect can be obtained by using 02.

Effects of the Invention As detailed above, by using the present invention, for example, 0
．． Even ultra-fine resist patterns with a line width of 5 μm or less can be easily formed.

FIG.

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Claims (3)

[Claims] (1) Forming a resist pattern in a predetermined shape on the substrate,
After isotropically irradiating the same resist pattern with plasma containing F or Cl, the resist is anisotropically etched to a predetermined thickness by reactive ion etching using O_2 gas, and then immersed in an organic solvent. A resist pattern forming method characterized by comprising steps. (2) The resist pattern forming method according to claim 1, wherein the resist forming the predetermined shape is a diazo novolac resin. (3) The resist pattern forming method according to claim 1, wherein the organic solvent is isoamyl acetate.