JPS58155722A - Manufacture of inorganic thin film - Google Patents

Abstract

PURPOSE:To make it possible to manufacture an inorganic thin film locally containing a metallic impurity without the need for a treatment with aqua regia, by locally exposing a metal thin film laminated on an inorganic thin film. CONSTITUTION:An inorganic thin film is formed on a substrate, and a metal thin film is laminated on the inorganic thin film. Then, the metal thin film is subjected to a local exposure having an intensity sufficient for the metal forming the metal thin film to move. As a result, the metal forming the metal thin film in the non-exposed region is absorbed in the inorganic thin film in the exposed region, so that the metal is absorbed in almost only the inorganic thin film in the exposed region. By this method, it is possible to manufacture an inorganic thin film locally containing a metallic impurity without the need for a treatment with aqua regia which may damage the whole of the inorganic thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an inorganic thin film locally containing metal impurities.

Conventionally, the following method has been used to produce an inorganic thin film locally containing metal impurities.

Inorganic thin films such as As-S and Se-■ are produced by laminating a metal thin film on top of the inorganic thin film and irradiating the metal thin film with local light.
The metal that formed the metal thin film in the irradiated area is 1 in the inorganic thin film.
2 absorption properties are known. This is a method that utilizes this property to remove an inorganic thin film that has a region where local metal has been absorbed as described above.

The reason why wet processing is performed to remove the metal thin film in the non-irradiated area is that it is impossible to remove only the metal thin film on the inorganic thin film using current dry processing.

However, in the above-described method, since the entire inorganic thin film is treated with water, there is a drawback that the entire inorganic thin film including the irradiated area may be damaged.

In order to solve these drawbacks, the present invention makes use of the properties that metal on an inorganic thin film becomes possible with exposure to light, and uses local exposure to expose unexposed areas forming a metal thin film on an inorganic thin film. This method produces an inorganic thin film that absorbs metal into the inorganic thin film in the exposed area.

That is, the present inventors discovered that as the exposure amount was increased, the metal thin film on the inorganic thin film was deformed. Further detailed examination revealed that the metal in the non-exposed area forming the metal thin film was absorbed into the inorganic thin film in the exposed area.

FIG. 1 clarifies the relationship between exposure amount and metal absorption in the present invention. Ag with a thickness of 50A on an inorganic thin film of SeGe with a thickness of about 3000A
A thin film was provided, a plurality of 50 μmφ patterns were provided on the Ag thin film, and local exposure was performed at the center of the Ag pattern with a 10 μmφ pattern and a 20 μmφ pattern while changing the exposure amount. Here, exposure was performed using a Cr mask,
UV light of mW/cm2 was used. In FIG. 1, an Ag pattern was formed when the inorganic thin film was subjected to CF4 plasma etching for 40 seconds immediately after exposure. It also shows the exposure dose dependence of the residual film rate of the inorganic thin film in the non-exposed area. The remaining film rate in the non-exposed area is related to Ag absorption from the following points. That is, Se with a Ag thin film provided on the upper layer
The Ge thin film and the SeGe thin film absorbed by Ag are not etched by the plasma etching process. The fact that the SeGe thin film in the non-exposed region is thinner than this indicates that the elements in the metal thin film in the non-exposed region (1) are reduced by exposure.

In Figure 1, when a pattern of 20 μmφ was exposed, the exposure amount was about 0.7 J/cm2, and the SeG
The e-thin film has completely disappeared, and when a 10 μmφ pattern is exposed, the Ag forming the SeGe thin film in the non-exposed area moves by about 1 S μm at an exposure dose of approximately 1 J/cm2, and is absorbed into the SeGe thin film in the exposed area. This means that it has been done.

Further, when the Ag thin film was set to 100 A, a pattern of 50 μmφ was formed, and a pattern of 10 μmφ was exposed at the center, the SeGe thin film patterned with Ag at about 1.3 J/cm 2 completely disappeared. Furthermore, 30% of Ag thin film was added.
A, when the exposure pattern is 10μmφ, 0.6J/c
At m2, the SeGe thin film under the Ag pattern completely disappeared.

However, when using a 30A Ag thin film, the film thickness was slightly thinner in the exposed area as well. This occurred because the total amount of Ag in the exposed area was small. Also, when Cn was used as the metal thin film, results similar to those obtained with the Ag thin film were obtained. Furthermore, when an inorganic thin film made of As2s3 with a thickness of 3000A was exposed to a pattern of 10 μmφ in the same manner as described above, the As2s3 thin film in the unexposed area under the metal pattern was completely exposed at approximately 1.5 J/cm2. lost.

The above results were obtained by exposing a patterned metal thin film to clarify the exposure dose dependence of the amount of metal movement, but even if local exposure was performed to a metal thin film formed entirely on the main surface. It is clear that similar results are obtained.

Using these results, it is possible to obtain thin films with locally different orientations by only local light irradiation. The film quality is due to the fact that it contains metal elements, and has etching resistance, reflection, etc.

Depending on these differences in membrane pressure, it can be applied to the following areas.

(1) Completely dry semiconductor pattern formation using inorganic resist.

This utilizes the enhanced etching resistance of the inorganic thin film due to its metal content.

(2) Selective diffusion source to the semiconductor substrate.

This uses locally absorbed metal as a diffusion source.

(3) Optical memory film.

This utilizes the difference in reflectance and transmittance between regions that contain metal and regions that do not.

Claims (1)

[Claims] 1. Forming an inorganic thin film on a substrate, laminating a metal thin film on top of the inorganic thin film, and subjecting the metal thin film to local exposure with sufficient intensity to move the metal forming the metal thin film. The process is characterized in that the metal in the non-exposed area of the metal thin film is absorbed into the inorganic thin film in the exposed area to form an inorganic thin film in which the metal is absorbed substantially only in the inorganic thin film in the exposed area. A method for producing an inorganic thin film.