JPS60224776A - Thin film forming device - Google Patents

Abstract

PURPOSE:To provide a thin film forming device which suppresses contamination of an evaporating source and suppresses the evaporating rate from the evaporating source and the change of an evaporating component in the stage of forming a film contg. the material evaporating from the evaporating source as one component in a gas discharge atmosphere by disposing a cover member around said evaporating source. CONSTITUTION:Preferably a gas consisting essentially of hydrocarbon is supplied through a gas introducing pipe 3 into a vacuum vessel 1 and the gas is discharged by a coiled discharge electrode 5 to evaporate the evaporating source 7 consisting of a metal such as Ag, etc. or metalloid such as Te, etc. by resistance heating or electric heating with an electron gun in the gas discharge atmosphere. The evaporating molecules form the discharge polymerized film consisting of the org. metal on a substrate 8 facing the source 7. The cover member 9 made of a stainless steel or the like which has heat resistance and decreases adsorption and release of gas is disposed around the source 7 and a crucible 6 in this stage and the top surface 10 of the member 9 is made preferably of a meshed or perforated plate to prevent the contamination of the source 7.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a film forming apparatus suitable for forming a film in which one component is a substance evaporated from an evaporation source in an ionized or activated gas. In particular, the present invention relates to a film forming apparatus capable of suppressing changes in the evaporation rate of the substance.

[Prior art and its problems]

Traditionally, compounds such as carbides, oxides, nitrides, and sulfides have two problems: when their melting points are high, they are difficult to evaporate, and even when their melting points are low, there is a difference between the evaporation source composition and the formed film composition. For these reasons, it has been difficult to form a film by ordinary vacuum deposition. In order to overcome these difficulties, K.
, oxygen gas, nitrogen gas ionized or activated by discharge voltage.

BACKGROUND ART It has become common practice to evaporate metals or semimetals in an atmosphere of sulfur gas or hydrocarbon gas to form films of oxides, nitrides, sulfides, carbides, or the like. It was the last time.
By such a method, for example, a film in which gold 6 or a metalloid is dispersed in a polymerized film.

It has become possible to form films with structures that cannot be obtained with normal vacuum evaporation.

By the way, when using the above-mentioned film formation method, the discharge voltage promotes reactions between gas molecules and evaporated molecules, as well as reactions between gas molecules, resulting in a high-quality film. There may be reactions between molecules and the evaporation source, and between gas molecules and the heating mechanism of the evaporation source. Furthermore, reaction products in the gas may adhere to the evaporation source and its heating mechanism. Contamination by these reaction products of the evaporation source changes the evaporation rate and evaporation components from the evaporation source.

This causes the problem of deterioration of film quality. Also, in film forming equipment, contamination due to reaction products of the heating mechanism,
Furthermore, deterioration becomes a problem.

[Purpose of the invention]

An object of the present invention is to overcome the problem of contamination caused by the reaction products mentioned above by disposing a cover member around the evaporation source and its heating mechanism, and to suppress changes in the evaporation rate and evaporation components from the evaporation source. It is in.

[Summary of the invention]

Reaction products that contaminate the evaporation source and its heating mechanism are generated in the plasma of the electrical discharge body or at the contact portion between the solid and the plasma. Therefore, the above object of the present invention can be achieved by installing a cover member near the evaporation source to shield the evaporation source and its heating mechanism from plasma.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Embodiments of the invention]

FIG. 1 is a schematic cross-sectional view of a film forming apparatus for deposition in a gas discharge field. In this apparatus, a vacuum chamber 1 is connected to a vacuum pump A (not shown) via an exhaust pipe 2, and is evacuated to an initial pressure of 1X10-5 Torr or less.

Next, hydrocarbon gas is supplied through a gas introduction pipe 3 leading into the vacuum chamber 1, and a main pulp 4 provided in the middle of the exhaust pipe 2 is supplied with hydrocarbon gas.
Adjust the exhaust capacity by
Xl0'Torr K is set. This pressure is 10
' Below Torr, the discharge becomes unstable and l To
Above rr, it becomes difficult for the evaporated molecules to reach the substrate. The introduced gas C is heated to 1 by a high frequency power source B (not shown).
Coiled discharge electrode 5 energized with a high frequency of 356MHz
This causes a discharge and active gas plasma spreads within the vacuum chamber.

A resistance-heated crucible 6 and a metal or metalloid evaporation source 7 are installed in advance in the vacuum chamber, and evaporated molecules from the crucible 6 pass through active gas plasma and reach the substrate 8 .

By such a method, for example, C as the gas to be introduced.
When Ag or Te is selected as H, gas, or evaporation source, alkyl Ag or alkyl T is formed in the methane polymer film on the substrate 8.
e, and an odor in which Ag atoms or Te atoms are mixed is formed. These are hereinafter referred to as organometallic discharge polymerized films.

This organometallic discharge polymerized film has high performance as an optical information recording medium for recording and reading information using laser light, and is particularly known for its high sensitivity and long-term stability.

By the way, when forming these organometallic discharge polymerized films,
As mentioned above, the problem is that the evaporation source 7 and the crucible 6 are contaminated by reaction products. Therefore, in the present invention, a cover member grounded around the evaporation source 7 and the crucible 6 is used. 9 was placed.

A detailed sectional view thereof is shown in FIG.

The upper surface 10 of the cover member located above the evaporation source needs to be in the shape of a pressure line or a perforated plate in order for the evaporated molecules to pass through. In addition, in order to prevent plasma from entering, the opening diameter of each hole in the upper surface 10 of the cover member, the opening diameter of the hole through which the resistance heating conduction path (not shown) is passed, and the distance between the inner walls of the cover member must be adjusted. It is desirable that the ductility is the same as or less than the mean free path of the gas in the vacuum chamber. The material of the hippopotamus has heat resistance, adsorption of gas,
It is desirable to choose a material that releases less emissions, such as stainless steel. As long as the above requirements are met, the same effect can be produced no matter what shape the cover member has or even if the entire cover member is made of the same material in the form of a mesh or a perforated plate. However, since evaporated molecules solidify on the inside of the upper surface 10 of the cover member, it is desirable to have a structural pressure that can be easily removed to remove deposits.

Below, an example of the results of an experiment investigating the effect of this cover member will be described. CH as introduced gas.

This is a case where an organometallic discharge polymerized film was formed using gas, Ag as an evaporation source, and stainless steel mesh as a cover member. In the experiment, Ag was evaporated while keeping the temperature constant in CH4 gas introduced in advance and set at a pressure of 5 mTorr, and the evaporation rate of Ag was successively measured. Third
The figure shows the experimental results when the discharge power was 200 W, where the horizontal axis is time and the vertical axis is the evaporation rate of Ag. When the cover material is not used (dotted chain line a), the evaporation rate decreases to less than half within 1 minute after the start of discharge, whereas when the cover material is installed (solid line b), the evaporation rate is reduced to less than 1/2 after 20 minutes after the start of discharge. Small fruits with no change in evaporation rate were observed. One reason for this is thought to be that when a cover member is not used, a film of carbon or carbide is formed on the surface of the evaporation source when discharge starts (point 0). First, the lifespan of the crucible has increased dramatically.

As described above, by using the cover member 9 to suppress contamination of the evaporation source, a more homogeneous and better quality organometallic polymer film can be formed, and deterioration of the heating means of the evaporation source can be suppressed. This method uses not only Ag as an evaporation source but also metals such as At, Au, and In, or Te, Bi, and S.
It is also effective for semimetals such as e, Si, Ge, etc.
Also, CH is introduced as a gas.

It is effective not only for gases but also for hydrocarbon gases or mixtures of hydrocarbon gases and inert gases.

Although the present invention has been exemplified above, the embodiments described above can be modified in many ways based on the technical idea of the present invention. For example, the effect of the cover material is not limited to the evaporation source and its heating means, but also to other parts in the vacuum chamber where contamination with reaction products is a problem, such as the shutter and the substrate. It can also be applied to rotation mechanisms, etc. In addition, the heating means for the evaporation source can be not only resistance heating but also an electron gun heating device, the electrode for causing the discharge can be installed outside the vacuum chamber, and the electrode shape can also be a counter electrode. Of course there is.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an example of an apparatus suitable for implementing the film forming method according to the present invention. FIG. 2 is a partially enlarged sectional view of the vicinity of the evaporation source in FIG. 1. FIG. 3 is an experimental example showing the effects of the present invention. 1... Vacuum chamber, 2 - Exhaust pipe, 3... Gas introduction pipe,
4... Main pulp, 5... Coiled discharge electrode, 6...
7... Evaporation source, 8... Substrate, 9... Cover member, 10... Upper surface of cover member. Agent: Patent attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2 1ρ / Figure 3 Keiyaki←Toge

Claims (1)

[Scope of Claims] (1) An evaporation source, a substrate facing the evaporation source, a waste introduction tube, etc. are arranged under an internal pressure of an empty chamber, and the gas introduced into the vacuum chamber is discharged, and the evaporation source is placed in the gas discharge atmosphere. 2. The thin film forming apparatus according to claim 1, wherein the heating means of the evaporation source (2) comprises a resistance heating device to form a film containing a substance that has been evaporated as a component. (3) The thin film forming apparatus according to claim 1, wherein the heating means for the evaporation source comprises an electron gun heating device. (4) A means for discharging gas is arranged at least either inside the vacuum chamber or outside the vacuum chamber, and the counter electrode or the coiled box 1
2. The thin film forming apparatus according to claim 1, comprising a discharge device having a pole. (5) The thin film forming apparatus according to claim 1, wherein the portion of the cover member on the substrate side when viewed from the evaporation source has a mesh shape or a perforated plate shape. (6) Claim 1, characterized in that the evaporation source is one of metals such as Ag, At, At+, In, or metalloids such as Te, Bi, Se, Si, Oe, etc. thin film forming equipment. (7) The iWv! according to claim 1, characterized in that the gas introduced into the vacuum chamber and discharged is a hydrocarbon gas or a mixture thereof with an inert gas! Forming device.