JPH06204164A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve step coverage of a second layer electrode in the electrode two-layered structure of a transistor. CONSTITUTION:Photoresist 4 is turned into a smooth form by baking, and subsequently turned into a form wherein the taper angle is gentle by anisotropically etching an interlayer insulating film 2. The step coverage of film thickness of a second layer electrode 3 is improved by 50%. Wire disconnection failure due to that the film is thinned down can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device having an improved through hole portion structure of a transistor electrode two-layer structure.

[0002]

2. Description of the Related Art A sectional view of an electrode two-layer structure portion of a semiconductor device having a conventional electrode two-layer structure is shown in FIG. 4 and a process sectional view thereof is shown in FIG.

FIG. 4 shows an interlayer insulating film 2 on the first layer electrode 1.
The second layer electrode 3 is formed via the. Next, the manufacturing method will be described with reference to FIG. First, as shown in FIG. 3A, an interlayer insulating film 2 which is a film to be etched is formed on the first layer electrode 1 to a film thickness of about 1.8 ± 0.3 μm, and an etching mask is formed thereon. . The photoresist film 4 is formed to a film thickness of about 2.0 μm. Next, as shown in FIG. 3B, the photoresist film 4 is opened by a known photolithography technique.

Next, as shown in FIG. 3C, baking (temperature 135 ° C., time 50 minutes) is performed to improve the adhesion between the interlayer insulating film 2 and the photoresist 4. Next, FIG.
As shown in (d), isotropic etching is performed by dry etching using the photoresist film 4 as a mask.

Next, as shown in FIG. 3 (e), the photoresist film 4 is removed, and the second layer electrode 3 is formed by vapor deposition to a thickness of about 2.0 μm by a known technique. )
It is obtained as a structure shown in.

[0006]

In the conventional method for manufacturing a semiconductor device described above, since the shape of the interlayer insulating film 2 is sharply cut at the end of the through hole portion, the step coverage of the electrode film of the second layer electrode 3 is covered. However, there was a problem of disconnection failure due to deterioration of the film thickness and thin film thickness.

An object of the present invention is to provide a method of manufacturing a semiconductor device having a two-layer structure of electrodes which does not cause disconnection failure.

[0008]

According to the method of manufacturing a semiconductor device of the present invention, the photoresist temperature is increased by increasing the baking temperature of the opened photoresist film on the interlayer insulating film formed on the lower first electrode. By smoothing the shape of the opening end of the mask, and by anisotropically etching the interlayer insulating film using the photoresist film having the smoothed opening end as a mask, the taper angle of the through hole is formed smoothly, and the upper layer first layer is formed. It is configured by forming two electrodes.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a through-hole manufacturing process of a two-layer electrode structure of a transistor according to an embodiment of the present invention, and FIG. 2 is a cross-section of the two-layer electrode structure of a semiconductor device manufactured according to an embodiment of the present invention. It is a figure.

As shown in FIG. 1A, an interlayer insulating film 2 which is a film to be etched is formed on the first layer electrode 1 to have a film thickness of about 1.8 μm ± 0.3 μm, and an etching mask is formed thereon. A photoresist film 4 having a thickness of about 2.0 μm is formed. Next, as shown in FIG. 1B, the photoresist film 4 is opened by a known photolithography technique. Then, as shown in FIG. 1C, baking is performed at a temperature of 16
The photoresist film 4 is formed into a smooth shape at 0 ° C. for 50 minutes.

Next, as shown in FIG. 1D, RIE is performed using the photoresist film 4 having a smooth shape as a mask.
Then, by anisotropically etching the interlayer insulating film 2 in the vertical direction, the etching shape becomes almost the same as that of the smoothed photoresist film 4. The interlayer insulating film 2 formed as a result has a smooth taper angle as illustrated.

Next, as shown in FIG. 1 (e), after removing the photoresist film 4, a second layer electrode 3 is vapor-deposited by a known technique to a thickness of about 2.0 μm as shown in FIG. 1 (f). To form.

According to the above steps, since the taper angle of the shape of the interlayer insulating film 2 is smooth, the film thickness of the second layer electrode 3 becomes thin as shown in FIG. There is no disconnection or vapor deposition formation, step coverage is improved, and there is no disconnection failure due to a thin film thickness.

Table 1 shows the results of step coverage for the electrode windows formed by the conventional method and the embodiment of the present invention.

[0015]

[Table 1]

From the results of Table 1, the step coverage is about 50% compared with the conventional example even if the interlayer insulating film thickness fluctuates within the standard.
Improvements have been obtained from experimental data.

[0017]

As described above, according to the present invention, in the two-layer structure of the electrode of the transistor, the photoresist is made into a smooth shape by baking, and the interlayer insulating film is anisotropically etched to form a smooth taper angle. Thereby, the step coverage of the film thickness of the second layer electrode can be improved by about 50%, and the disconnection defect due to the thin film thickness can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an electrode two-layer structure portion of a transistor, which is shown in order of steps for explaining an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a two-layer structure of electrodes of a transistor formed according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of the electrode two-layer structure portion of the transistor shown in the order of steps for explaining an example of the conventional method for manufacturing a semiconductor device.

FIG. 4 is an electrode 2 of a transistor formed by a conventional example.
It is sectional drawing of a layer structure part.

[Explanation of symbols]

 1 First Layer Electrode 2 Interlayer Insulation Film 3 Second Layer Electrode 4 Photoresist Film

Claims (1)

[Claims] 1. A step of forming a first layer electrode and the first step
A step of forming an interlayer insulating film on the layer electrode, a step of forming a photoresist film on the interlayer insulating film and forming an opening in the photoresist film, and a step of forming the opening-formed photoresist film at a high temperature. Baking and smoothing the shape of the opening end of the photoresist; and anisotropic etching of the interlayer insulating film in the vertical direction by RIE using the photoresist as a mask to taper the interlayer insulating film to the same shape as the photoresist. A step of forming a through hole with smooth corners,
A step of forming a second layer electrode after removing the photoresist, a method of manufacturing a semiconductor device.