JPS5852330B2 - Manufacturing method of semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device using a synthetic resin, and particularly to a method for forming a silicon oxide film.

Conventionally, silicon oxide films have been formed at relatively high temperatures using vapor phase growth methods, thermal oxidation methods, etc., and therefore, when applied to semiconductor devices using low melting point metals such as aluminum oxide (μAt), there have been problems such as alloying.

The present invention provides a method for easily forming a silicon oxide film at a relatively low temperature, and is characterized by converting a silicon resin film into a silicon oxide film by irradiating oxygen plasma.

The present invention is based on the discovery that when a silicon resin film is irradiated with oxygen plasma, it is converted into a silicon oxide film.The effectiveness of the present invention will be clarified from the following experimental example.

Apply silicon resin to a thickness of about 2 cm on a substrate such as silicon semiconductor crystal.
,000 people, 900G for 15 minutes, 300g
Heat treatment is performed at ~450° C. for 10 to 30 minutes to harden the silicone resin film.

The silicone resin film thus treated is not etched by a hydrofluoric acid etching solution, which is normally an etching solution for silicon oxide films.

However, when the substrate is exposed to oxygen gas pressure I Torr and output ioo
When the film is left in an oxygen plasma atmosphere generated by W for about 15 minutes, the thickness of the film becomes about 1/2, i, oooλ, and is etched with a hydrofluoric acid etching solution.

The etching rate of the film is as follows:
Approximately 5,000 yen per minute, the same as phosphorus silicate glass
It is etched at the speed of 0 people.

When converting the entire surface of the silicone resin film into an oxide film, the thickness of the silicone resin film is preferably 2,000 Å or less.

If the thickness of the silicone resin film is 2.0 OOA or more, cracks will occur in the film that has been altered by oxygen plasma irradiation.

The maximum substrate temperature during oxygen plasma irradiation is 200°C,
Silicon oxide film can be obtained at low temperature.

Next, an embodiment in which the present invention is applied to an interlayer insulating film of a so-called multilayer wiring will be described with reference to the drawings.

Conventionally, this multilayer wiring is made by depositing aluminum (At) on a semiconductor substrate 1, forming a first layer wiring 2 with a desired wiring pattern by photo-etching, and then applying low-temperature etching on top of the first layer wiring 2, as shown in FIG. Silicon dioxide (S
102) After providing the insulating layer 3 and forming through holes etc. in the insulating layer, At is deposited again and the second layer wiring 4 of the desired wiring pattern is formed by photo-etching, and further etching is performed if necessary. Multilayer wiring was formed by repeating the above steps.

Therefore, the insulating layer 3 and the second wiring layer 4 at the corner portions of the first layer wiring 2 are thinner than the other portions due to the sharp stepped portions, which has the disadvantage that poor insulation and disconnection of the second layer wiring 4 are likely to occur. there were.

In order to eliminate this drawback, it is necessary to make the insulating layer 3 and the second layer wiring 4 thicker than necessary, which makes the unevenness even more severe. Once again, the above-mentioned drawbacks appeared, reducing the reliability of the bill.

Further, since At in the wiring layer is melted and alloyed at a relatively low temperature, the wiring interlayer insulating film must be formed at a relatively low temperature.

For this reason, methods using synthetic resins such as silicone resin and polyimide resin as interlayer insulating films have been proposed, but when forming contact windows by photo-etching,
Due to the strong alkaline etching solution for synthetic resins, the photoresist pattern becomes unclear and the At wiring and semiconductor substrates are contaminated with alkali ions.

If the present invention is applied to a wiring interlayer insulating film, the above-mentioned drawbacks can be solved.

That is, as shown in FIG. 2a, after aluminum (At) is deposited on the semiconductor substrate 11 and the first layer wiring 12 of a desired wiring pattern is formed by photoetching,
Applying silicone resin to cover the first layer wiring 12,
Heat treatment is performed at 90° C. for about 15 minutes to harden the silicone resin film 15.

Since the silicone resin is a viscous liquid, it compensates for the stepped portion of the fourth layer wiring 120 and forms a smooth surface as a whole.

Next, the substrate was subjected to an oxygen gas pressure of I Torr and an output of 100 W.
The silicone resin film 15 is converted into a silicon oxide film 16 by irradiating the silicone resin film 15 with oxygen plasma generated for about 15 minutes.

Next, as shown in Figure 2, phosphorus silicate
A glass (PSG) layer is grown in vapor phase or liquid phase silicon oxide 17 is applied.

This is because the altered silicon oxide film 16 is porous unlike a vapor-phase grown silicon oxide film, so by covering it with PSG or the like, reliability is improved.

Next, as shown in FIG. 2C, the PSG or silicon oxide film 17 and the silicon oxide film 1 formed by oxygen plasma
A photo film of ordinary silicon oxide film is applied to the insulating layer consisting of 6.
In the same manner as etching, a contact window 18 for wiring is formed, A4 is deposited, and a second layer wiring 14 having a desired wiring pattern is formed by photo-etching.

As described above, if the interlayer insulating film of the multilayer wiring is formed according to the present invention, contact windows in the wiring layer can be easily formed, and there are advantages that disconnection of the At wiring layer can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional multilayer wiring method, and FIG. 2 is a partial process diagram of a multilayer wiring according to the present invention. 11... Semiconductor substrate, 12... First layer wiring, 14... Second layer wiring, 15...
Silicon resin film, 16... Altered silicon oxide film, 17... PSG film is vapor phase grown silicon oxide film, 3... Vapor phase grown silicon oxide film.

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor device, which comprises converting a silicone resin film into a silicon oxide film by oxygen plasma irradiation.