JPS63287019A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the breakdown of the upper metal layer of a contact part and to facilitate the manufacture of a semiconductor device, when a contact window is opened, by removing a reaction product, which is attached to the sidewall of the contact window, by reactive ion etching using oxygen as etching gas. CONSTITUTION:An insulating film 2 such as an oxide film is formed on a semiconductor substrate 1. Photo resist 3 is formed thereon in a desired pattern. With the pattern of the resist 3 as a mask, the insulating film 2 at an unnecessary part is removed by reactive ion etching using plasma 4. At this time, a reaction product 5 called a sidewall is attached to the side part of a contact. A part of the resist 3 and the reaction product 5 are removed by reactive ion etching using O2 plasma 6. The resist 3 is further removed with organic solvent. A wiring metal layer 7 comprising aluminum and the like is deposited by a vacuum evaporation method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and relates to a method of forming contact holes by reactive ion etching.

[Conventional technology]

Conventionally, a method for manufacturing this type of semiconductor device has been carried out as follows.

FIGS. 3(a) to 3(d) are cross-sectional views of a semiconductor chip shown in order of steps to explain an example of a conventional method of manufacturing a semiconductor device.

First, as shown in FIG. 3(a)K, the top K of the semiconductor substrate 21 is
For example, an insulating film 22 such as an oxide film is formed, and then a desired pattern is formed using a photoresist 23.

Next, as shown in FIG. 3(b)K, using the pattern of the photoresist 23 as a mask, remove unnecessary portions of the insulation [22] using, for example, (CF4+H,) plasma 24. At this time, the side wall of the contact window is removed. A reaction product 25 called a sidewall is attached.

Subsequently, as shown in FIG. 3(C), photoresist 2
3 is removed, for example, with an organic solvent. At this time, since the reaction product 25 cannot be removed with an organic solvent, it remains attached to the side wall of the contact window.

Finally, as shown in FIG. 3 (d3), a wiring metal 27 such as aluminum is deposited on the surface by vacuum deposition.

[Problem that the invention seeks to solve]

In the conventional semiconductor device manufacturing method described above, since the reaction product 25 remains on the side wall of the contact window, for example, when heat treatment is performed, gas is generated from the reaction product 25.
There is a drawback that the upper layer wiring metal 27 is pressed, and if the pressure is excessive, the upper layer wiring metal 27 may be disconnected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device that solves the above-mentioned drawbacks and prevents the occurrence of an accident in which the upper layer metal wiring is disconnected.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes a step of forming an insulating film on a semiconductor substrate, a step of forming a photoresist in a predetermined pattern on the insulating film, and a step of forming a first photoresist using the photoresist as a mask. A step of removing the insulating film and opening a contact window by reactive ion etching, and a second reactive ion etching process using oxygen as an etching gas, remove a portion of the photoresist and the contact window. The method is characterized in that it includes a step of removing a reaction product.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIGS. 1(a) to 1(e) are cross-sectional views of a semiconductor chip showing a method for manufacturing a semiconductor device according to a first embodiment of the present invention in order of steps.

First, as shown in FIG. 1(a), an insulating film 2 such as an oxide film is formed on the semiconductor substrate 1, and then a photoresist 3 is formed.
is formed into a desired pattern.

Next, as shown in FIG. 1Cb), using the pattern of the photoresist 3 as a mask, unnecessary parts of the insulating film 2 are removed, for example (Cb).
F, +112) Remove the holes by reactive ion etching using plasma 4. At this time, the side wall of the contact window is etched.
A reaction product 5 called a sidewall is attached.

After this, the photoresist 3 is etched by reactive ion etching using 02 plasma 6 as shown in FIG.
and reaction product 5 are removed.

Subsequently, as shown in FIG. 1(d), the photoresist 3 is removed using an organic solvent.

Finally, as shown in FIG. 1(e), a wiring metal 7 made of, for example, aluminum is deposited by vacuum evaporation.

FIGS. 2(a) to 2(e) are cross-sectional views of a semiconductor chip showing a method for manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps.

First, as shown in FIG. 2(a), first, as shown in FIG.
For example, an insulating film 12 such as an oxide film is formed, and then a photoresist 13 is formed in a desired pattern.

Next, as shown in FIG. 2(b), using the pattern of the photoresist 13 as a mask, unnecessary portions of the insulating film 12 are removed by reactive ion etching using, for example, (CF4+H2) plasma 14. At this time, a reaction product 15 called a sidewall adheres to the sidewall of the contact window.

Thereafter, as shown in FIG. 2(c)K, a part of the photoresist 13 and the 1 reaction product 15 are removed by reactive ion etching using 02 plasma 16. Then the second
As shown in Figure (d), the photoresist 13 is removed using an organic solvent.

Finally, as shown in FIG. 2(e)K, a wiring metal 17, such as aluminum, is deposited by vacuum evaporation.

〔Effect of the invention〕

As explained above, the present invention uses reactive ion etching using oxygen as an etching gas to remove reaction products that adhere to the side walls of the contact window when opening the contact window. This has the effect of preventing disconnection of the upper metal at the contact portion.

[Brief explanation of drawings]

1(a) to 1(e) are cross-sectional views of a semiconductor substrate showing the manufacturing method of a semiconductor device according to the first embodiment of the present invention in the order of steps, and FIGS. 2(a) to 2(e) e) is the second aspect of the present invention.
FIGS. 3(a) to 3(d) are cross-sectional views of a semiconductor substrate showing a conventional method for manufacturing a semiconductor device in order of steps. 1.11.21...Semiconductor substrate, 2,12.22...
・Insulating film, 3, 13.23... Photoresist, 4, 1
4,24...(CF4+H2) plasma, 5,15.
25...reaction product, 6,16...02 plasma,
7.17, 27.18... Wiring metal. Agent: Susumu Uchihara, patent attorney
(C) (!A)
(d) (e) Figure 1 Figure 22 <(1')(C') Figure j

Claims (1)

[Claims] A method for manufacturing a semiconductor device in which a contact hole is formed in a semiconductor substrate, which includes the steps of forming an insulating film on the semiconductor substrate, forming a photoresist in a predetermined pattern on the insulating film, and masking the photoresist. A step of partially removing the insulating film and opening a contact window by a first reactive ion etching process, and a second reactive ion etching process using oxygen as an etching gas to partially remove the photoresist. and a step of removing reaction products adhering to the contact window.