JPS6130662A - Thin film forming device - Google Patents

Abstract

PURPOSE:To prevent the exfoliation of a film material sticking to an antisticking plate, the resticking thereof onto a substrate for formation of a thin film and the consequent deterioration in the quality of the thin film by providing the antisticking plate consisting of a material having a small difference in surface energy from the film material in a vacuum vessel of a film forming device such as vacuum deposition device. CONSTITUTION:Te, etc. from a vapor source 5 stick to the inside surface of the vacuum vessel 3 in the stage of depositing the thin film by evaporation onto the substrate 4 in the chamber 3 from the vapor source 5 of the low-melting point compd. such as Te and the compd. thereof in a vacuum deposition method, sputtering method, etc. The sticking material exfoliates and resticks onto the substrate 4 thus deteriorating the quality of the thin Te film on the substrate 4. The antisticking plate 7 made of Al or tetrafluoroethylene material, etc. having the small difference in surface energy from the Te is installed in the vessel 3 in order to prevent such sticking. The Te sticking to the surface of the plate 7 exfoliates hardly and therefore the sticking of the Te to the surface of the substrate 4 and the deterioration in the quality of the Te film are obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film forming apparatus for vacuum evaporation, sputtering, etc.

Conventional configuration and its problems In conventional thin film forming equipment such as vacuum evaporation and sputtering, deposits made of thin film materials on the surfaces of chamber internal structures such as deposition prevention plates and shutters peel off and re-adhere to the substrate. However, the problem was that defects such as pinholes occurred. A conventional example will be described below with reference to FIG.

Deposit 2 on the surface of chamber internal structure 1 of thin film forming apparatus
When condensed and deposited on this surface, strain accumulates inside and internal stress occurs. When this internal stress exceeded the adhesion force of the deposit 2 to the surface of the internal structure 1, peeling occurred.

In addition, peeling occurred due to vibrations and shocks caused by exhaust gas in the chamber, etc. 3/, -7. To prevent the above deposit from peeling off, deposit 2
The surface of the internal structure 1 is roughened by sandblasting, etc., with the aim of increasing the anchoring effect and increasing the actual adhesion area by biting into the slits on the surface of the internal structure 1 like an anchor. Attempts have been made to heat the surface of the internal structure 1 in order to reduce the internal strain caused by the condensation of the deposit 2.

However, due to surface roughening, gas tends to be adsorbed on the surface of the internal structure 1, making it impossible to exhaust the chamber sufficiently, and requiring a complicated heating device to heat the surface of the internal structure 1. There were problems and there were no practical measures to prevent peeling.

In addition, in low melting point deposited materials such as Te (tellurium) and its compounds, compared to high melting point materials such as nickel and titanium, the effect of reducing internal strain due to heating is small, and peeling of the deposit 2 is prevented. A new method was needed.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks, the present invention provides a thin film forming apparatus in which the adhesion of the deposits is strengthened to prevent the deposits from peeling off and falling, thereby reducing re-adhesion to the substrate.

Structure of the Invention The present invention is a thin film forming apparatus in which a chamber internal structure is made of a material with a small difference in surface energy from a thin film material, and the thin film forming apparatus can form a thin film from a thin film material without performing processing such as sandblasting or heating on the surface of the chamber internal structure. By reducing the surface energy difference between the deposits and each structure, the surface chemical conditions for deposit adhesion are optimized, preventing the deposits from peeling off and reducing re-adhesion to the substrate. have an effect.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, 3 is a chamber whose interior can be evacuated, 4 is a substrate installed in the chamber and on which a thin film is formed, 6 is an evaporation source installed opposite to the substrate 3 and generates vapor of To and its compounds; 7 is a shutter that blocks the vapor flow from the evaporation source to the substrate 4 and controls thin film formation, and 7 is an adhesion prevention plate made of aluminum and its alloy installed on the surface of the shutter 6 facing the evaporation source and on the inner wall of the chamber 3. In Figure 3, 8
is the deposit on the anti-adhesion plate 7.

The operation of the thin film forming apparatus configured as above will be explained.

The deposited molecules of To and its compounds that fly from the evaporation source 6 are condensed and solidified on the deposition prevention plate 7 and deposited on the deposition prevention plate 7 . Here, if an aluminum plate having a small surface energy difference from 're is used as the deposition prevention plate 7, peeling of the deposit can be prevented for the reasons described below.

The adhesion between the deposit 8 and the adhesion prevention plate 7 is thought to be due to van der Waals force, that is, intermolecular force, or due to mutual diffusion. However, since the deposit 8 of To and its compounds in the present invention is formed at a relatively low temperature, interdiffusion is difficult to occur, and the adhesion of the deposit 8 to the adhesion prevention plate 7 is due to intermolecular force. Lord. Therefore, when considering measures to prevent peeling, the deposit 8 and the adhesion prevention plate 7 are
6. It is important to find the optimal conditions for adhesion due to intermolecular forces. This condition is to make the surface tension, that is, the surface energy of the adhesion prevention plate 7 and the deposit 8 equal (strictly speaking, their non-polar component and polar component are equal, respectively). Also,
The smaller the surface energy difference, the greater the adhesion force. As an example of Te and its compounds, the relationship between the surface energy difference and the adhesion strength of Te low oxide deposits to adhesion prevention plates made of various materials when using Te low oxide is shown in the fourth section. As shown in the figure.

Compared to conventional stainless steel anti-adhesion plates, the aluminum plate has a surface energy difference of approximately
By using about 400 dyn-cm-'), the adhesion strength of the deposit 8 to the adhesion prevention plate 7 is more than doubled,
Deposition of deposits was reduced. In addition, the aluminum plate has a small amount of adsorbed gas, and when used as a constituent material for a vacuum, it has performance equivalent to or better than stainless steel, so there was no problem that the chamber could not be sufficiently evacuated.

Also, plastic materials such as tetrafluoroethylene (hereinafter abbreviated as Teflon) used as conventional adhesion prevention plates have a surface energy difference of about 150 dyn-1yH-' compared to stainless steel, which is about 150 dyn-1yH-'. It became clear that the adhesion strength was almost the same as that of an aluminum plate. Therefore, Teflon is suitable as an anti-adhesion plate material when used at temperatures below 20°C.

Effects of the Invention As described above, the present invention prevents deposits from peeling off from the chamber internal structure and prevents them from re-adhering to the substrate by configuring the chamber internal structure with a thin film material and a material with a small surface energy difference. It is possible to reduce the amount and improve the yield, and its practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view showing the surface part of the internal structure of a conventional thin film forming apparatus, and FIG. 2 is a Te
A schematic diagram showing the outline of a low oxide thin film forming apparatus, FIG. 3 is an enlarged sectional view showing the surface portion of an adhesion prevention plate in an embodiment of the present invention, and FIG. 4 shows the surface energy dependence of the adhesion strength of deposits. It is a diagram. 1... Internal structure, 2... Sediment, 3
...Chamber, 4...Substrate, 5...
... Evaporation source, 6. River... Shutter, 7... Deposition prevention plate, 8... Sediment.

Claims (4)

[Claims] (1) A chamber whose interior can be evacuated, a thin film forming means provided in the chamber and capable of forming a thin film on a substrate, a holder for holding the substrate, and a thin film deposited on the chamber and the parts of the substrate where thin film formation is not required. A thin film forming apparatus comprising a chamber internal structure such as an adhesion prevention plate provided to prevent the formation of adhesion, and the chamber internal structure is formed of a material having a small surface energy difference with respect to the thin film material. (2) The thin film forming apparatus according to claim 1, wherein the surface of the internal structure of the chamber is coated with a material having a small difference in surface energy from the thin film material. (3) When forming tellurium and its compounds as a thin film, the thin film forming apparatus according to claim 1 or 2 uses aluminum and its alloy as a material having a small difference in surface energy from the thin film material. (4) The thin film forming apparatus according to claim 1 or 2, which uses a tetrafluoroethylene material when forming tellurium and its compounds as a thin film.