JPS63146439A - Forming method for electrode of semiconductor device - Google Patents

Abstract

PURPOSE:To form the rounded part of a contact port by a simple process by forming a hole for opening a contact at a resist, then heat treating it to round the corners of the resist and then etching back it by RIE. CONSTITUTION:After a resist 21 is patterned to form a contact, the corners of the resist are rounded by heat treating at approx. 100-200 deg.C. An interlayer film, such as a silicon oxide film 22 is etched to a base, such as aluminum 23 by etch-back RIE to transfer the resist shape rounded at its corners to the silicon oxide film, thereby rounding a contact port. Thereafter, a wiring material, such as aluminum is deposited, and patterned to form an electrode. The base uses to be considered, in addition to the aluminum, Si, silicide or other alloy, etc.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for forming a semiconductor device.

(Merocrystalline technique) As semiconductor devices become smaller, the contact size decreases, but the thickness and size of interlayer films do not decrease significantly, so the ratio of the vertical length to the horizontal length of the contact hole (aspect ratio) becomes larger. Therefore, simply make a straight hole and fill it with a wiring material such as IJ.
f: When deposited, the M coverage on the bottom and side surfaces of the contact is low <, good; contact cannot be maintained. Figure 1 shows the conventional method used to improve this. First, remove the contact part of resist 11 (
a), 810212 using isotropic plasma etching
Etching only a part of the upper surface of Q)), then anisotropic etching (RIE) to make the base AA! By etching up to 13 and 81, a contact with an open side is formed ((C) to (e)). If the etching rate of plasma etching is significantly low, it is not possible to expand the contact depth.

(Problems to be Solved by the Invention) This invention improves the above-mentioned drawbacks of the conventional semiconductor device forming method, and enables rounding of contact holes through a simple process, even on films for which isotropic plasma etching cannot be used. The purpose is to

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a method of rounding the corners of the resist by applying heat treatment after forming holes for contact openings in the resist, and then performing etchmection RI.
A feature is that a rounded portion of the contact opening is formed by performing E.

(Function) The corners of the resist can be easily rounded by performing heat treatment for a short time at a relatively low temperature (more than 100 degrees Celsius).

Therefore, if the RIE etching selectivity between the resist and the interlayer film can be made sufficiently low, the shape of the resist can be directly transferred to the interlayer film. In particular, in the present invention, since the resist is fully rounded, its shape can be controlled by simple heat treatment, and the contact depth can be expanded even for interlayer films that are hardly etched by isotropic plasma etching. . Further, since the resist is completely removed by etchback RIE, no special process for removing the resist is required, which simplifies the process.

(Example) Next, reference will be made to the drawings for an embodiment of the present invention.

Explain in detail. FIGS. 2(a) to 2(e) are cross-sectional views for schematically explaining a method for forming a semiconductor device according to the present invention.

After patterning the resist 21 for contact formation (a), the corners are rounded by heat treatment (approximately 100 to 200°0), and the resist is used to form an interlayer film, such as a silicon oxide film, by etch-mec RIE. 2
By etching 2 to the base material, for example, A123, the resist shape with rounded corners is transferred to the silicon oxide film, and the contact area is rounded ((c), (d))
. After that, a wiring material such as Al is deposited.

and patterning to form an electrode (e). In addition to M, Sib silicide and other alloys may be used as the base.

〔Effect of the invention〕

According to the present invention, even for an interlayer film that is hardly etched by isotropic glazma etching, the contact hole can be rounded by a simple process and a good electrode can be formed.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the conventional electrode formation method. FIG. 2 is an explanatory diagram showing the electrode forming method in the present invention. 11...Resist 12...Silicon oxide film 13...Base A1 14...Upper layer Al 21...Resist

Claims (1)

[Claims] When forming electrodes of a semiconductor device, a resist with holes for contact holes is reflowed by heat treatment, its corners are rounded, and then the shape of the resist is transferred to an interlayer film for contact openings using etchback RIE. A method for forming an electrode of a semiconductor device, characterized in that contact rounding is thereby performed.