JPS63293832A - Low-temperature formation of thin film - Google Patents

Abstract

PURPOSE:To increase the deposition rate of a film, to improve the step coverage of the film and to shorten the treating time for forming the film by a method wherein the temperature of a substrate at the time of formation of the film is held at low temperature of 0 deg.C or less. CONSTITUTION:Gas is introduced in a vacuum container, the gas is brought in a plasma state by AC power and a film deposition 3 is performed on a substrate 1 by the generated plasma. At that time, the substrate 1 is held at low temperature of 0 deg.C or less. Whereupon, the adsorption rate of reaction particles, being incident into the substrate 1 from the plasma, to the surface of the substrate 1 is increased. Especially, the adsorption rate is increased at the corners of the step parts. Thereby, the deposition rate of a film is increased, the step coverage of the film is improved and the treating time for forming the film is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to film formation using plasma, and particularly to a method for forming a thin film with excellent surface coverage.

[Conventional technology]

In the conventional plasma CVD method, as described in Chapter 6, Section 3 of rMO8LSI Manufacturing Technology (published by McGraw-Hill), protection after AQ wiring is performed with the substrate temperature kept above room temperature and below 500°C. Formation of films and interlayer insulating films was carried out.

Formation of organic films using plasma polymerization is discussed in ``Proceedings of the 1983 Dry Process Symposium, Tokyo, p. 51.''

[Problem that the invention seeks to solve]

In the conventional method described above, film formation was performed at a temperature of room temperature or higher and 500° C. or lower. However, in that temperature range,
There was a drawback that the adsorption coefficient of the nine gaseous atoms to the substrate was small, resulting in a low deposition rate. Also,
In high step portions such as those seen in the submicron device formation process, surface coverage often deteriorates, resulting in a problem of low throughput.

An object of the present invention is to provide a film forming method that has a high deposition rate and has excellent coverage of stepped portions or deep grooves.

[Means for solving problems]

The above object is achieved by keeping the substrate temperature at a low temperature of 0° C. or lower during film formation.

[Effect]

When the substrate is cooled and kept at a low temperature of 0° C. or lower, the rate of adsorption of reactive particles incident on the substrate from the plasma onto the substrate surface increases, particularly at the edges of the stepped portions. Therefore, the deposition rate becomes high and the film is deposited quickly on the stepped portion, so that the coating rate is increased and the coverage is improved.

[Example] <Example 1> An example of the present invention will be described below with reference to FIG. 1. This example shows the temperature dependence of the film formation rate.

The apparatus used was a parallel plate plasma CVD apparatus, in which a substrate was placed on an anode electrode, and the electrode was cooled to bring the substrate to a low temperature. The gases introduced were 5111m and 02 gases to form 5iOzllll. As a result, it was found that when the gas pressure was maintained at 10 orr, the deposition rate increased when the substrate temperature was below 130°C. Further, in the temperature range of −30° C. or lower, the coverage of the one-step difference portion is also extremely good. An example of this is shown in FIG. It can be seen that the thickness of the deposited film is particularly thick at the stepped portions, and the coverage is improved.

As shown in Figure 2, if the film formation time is further increased, the flat 5
It was found that an i02 surface was obtained with extremely excellent coverage. The effective temperature range for deposition is gas pressure.

Varies depending on AC power. However, in either case, 13
It was effective at temperatures below 0°C, and was also effective at 10°C when the power was small and the deposition rate was relatively slow. That is, it is effective even at temperatures below 10°C.

Results of SiN film formation using a similar device.

Similar to the formation of 5iot, it was found that increased deposition rates and improved coverage could be achieved at low temperatures. In other words, not only in 5ins but also in the formation of SiN,
Fast film deposition is possible at sub-freezing temperatures. Further, according to the present invention, similar results were obtained in a CVD apparatus using microwave discharge.

<Example 2> Lowering the substrate temperature is also effective in increasing the formation rate of a polymer film using plasma.

A mixed gas of Ar, trimethyl methacrylate, and styrene was introduced into a quartz glass container in a capacitively coupled plasma generator to generate plasma, and a polymer film was deposited on a cooled substrate.

The deposition rate is 574 times that at room temperature at -10°C, -30
It was found that the temperature increases by 774 times at low temperatures. That is, the effect of cooling became greater at temperatures below 0°C.

【Effect of the invention〕

According to the present invention, it is possible to increase the deposition rate and improve step coverage, which is effective in shortening processing time and reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram of the dependence of film deposition rate on substrate temperature according to an embodiment of the present invention, and FIG. 2 is a sectional view of a substrate showing the shape of a film formed according to an embodiment of the present invention.

Claims (1)

[Claims] 1. In a film deposition method in which gas is introduced into a reduced pressure container, the gas is turned into plasma by AC power, and a film is deposited on the substrate by the generated plasma, the substrate is maintained at a low temperature of 0° C. or lower. A low-temperature thin film forming method characterized by: 2. The low-temperature thin film forming method according to claim 1, wherein the film-depositing substrate is placed in afterglow without being in direct contact with plasma.