JPS6188529A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a fine pattern by executing RIE using CF4 system gas to deep ultraviolet ray resist based on chloromethylstyrene (CMS) with a thin film of azide system ultraviolet ray resist used as a mask. CONSTITUTION:Aluminum 1 is coated with chloromethylstyrene CMS resist 2 and is baked and the surface is flattened. The CMS resist is not resistive to dry etching but is highly resistive to etching by C system gas plasma. Next, resist is coated with the azide system ultraviolet ray resist 3 in the thickness of about 1/3 of the thickness of resist 2 and is then exposed and developed. The resist 3 shows large resistivity to dry etching by CF4. Moreover, at the time of exposure, since the base is flat, the light is not reflected and a fine mask pattern of resist 3 can be obtained. With the CF4 gas, the CMS resist is dry-etched by RIE and thereby fine and vertical resist pattern can be obtained. According to this method, a problem of the stepped portion and thickness of resist which are not suitable for fining can be solved and fine pattern of 1mum or less can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for flattening a stepped portion on a semiconductor substrate and a method for forming a fine pattern.

[Conventional technology]

A semiconductor substrate on which a plurality of element regions are formed has a plurality of steps for an insulating layer for forming the element regions and a conductor layer led out from the element regions. This is extremely disadvantageous. - In microfabrication, reactive ion etching (hereinafter abbreviated as AID) is the mainstream), and a resist with good dry etching resistance is required.
The only way to form fine patterns is to use thick azide-based UV resists and wet develop them.

There is a limit.

Furthermore, since the shape of the resist affects microfabrication in IE, a vertical shape cannot be obtained by conventional wet development, and processing by dry etching is required.

[Problem that the invention seeks to solve]

In order to solve the above points, a multilayer resist method has been considered. Most conventional multilayer resists are based on a three-layer resist method with an intermediate layer.

This method is complicated in terms of process, and since 02 plasma is used to pattern the first resist layer, there is a problem in that it is difficult to obtain a vertical resist shape.

[Failure to solve the problem]

Therefore, according to the present invention, chloromethylstyrene (which has no dry etch resistance against CF4 plasma but has high dry etch resistance against chlorine gas plasma)
A deep ultra violet resist based on CM8 (hereinafter abbreviated as CM8) is used as the first layer, and an azide-based UV resist with high dry etch resistance against CF4 is used as the second layer.
This invention provides a two-layer resist method characterized in that the first layer CMS is patterned using a CF IE for the first layer.

〔Example〕

Embodiments of the present invention will be described below with reference to one drawing.

As shown in Fig. 1, KCM8 resist 2 is applied to the All surface to a thickness of 2 to 3 μm and baked to harden it (see figure).
. This makes it possible to soften the unevenness of the resist due to the step difference in Ae. As shown in FIG. 2, the CMS resist 2 has no dry etching resistance, but exhibits high dry etching resistance against chlorine gas plasma. After that, azide-based ultraviolet ray resist 2) is applied in a 3-minute step, exposed, and wet developed (Fig. 1 (uniform).Azide-based ultraviolet ray resist 2 is applied as shown in Fig. 2. High dry etching resistance against CF4.Next, the second layer of resist is applied and exposed, but at that time, the base is flat and there is no reflection, so forming a fil+pattern of the second layer of resist is extremely advantageous. .Next, CF
CM8 resist is dry-processed using R and IE using gas (Fig. 1 (q)). By using IE, a fine resist pattern can be created in a vertical shape. This has been a problem in the past. # Steps and resist thickness are disadvantageous to thinning.
This method solves the problem and allows formation of fine patterns of 1 μm or less.

〔Effect of the invention〕

In this embodiment, Ae patterning is performed, but it is particularly applicable to IE using chlorine-based gas. This resist called CMS is effective against IE using chlorine-based gas.

Ae because it shows particularly good dry etch resistance.

This method is effective not only for poly-8i but also for deep etching when performing isolation.

[Brief explanation of drawings]

1.4-(q is a sectional view showing the steps of an embodiment in which the present invention is applied to the Ae process, and FIG. 2 is a graph showing the etching rate of each resist. 1... Ae, 2...0MS resist,
3...Azide resist, 4...CF
4 Reactive ion etching, 5...
・Patterned Ae0 (C gloss hard

Claims (1)

[Claims] A step of using a thick chloromethylstyrene-based deep ultraviolet resist as a first layer on the semiconductor and a thin azide-based ultraviolet resist as a second layer, and using the second layer resist as a mask,
A method for manufacturing a semiconductor device, comprising the step of patterning the first layer by reactive ion etching using CF_4-based gas.