JPS60204879A - Formation of film by utilizing vapor phase reaction - Google Patents

Abstract

PURPOSE:To form a local covering in short time at a low cost without post working by concealing the non-film part of a work with a cover and closing the spacing between the cover and the work by a difference in the coefft. of thermal expansion between said cover and material to be worked in the stage of forming the film. CONSTITUTION:The non-film part of a circular cylindrical material 5 to be worked is locally concealed by a cover 9. The cover 9 is formed of an ''Invar'' alloy and has he inside diameter slightly larger than the outside diameter of the material. Such material is set on the tray 7 in a reaction furnace and the inside of the furnace is heated. Only the gaseous H2 is passed until the reaction temp. is attained. The material 5 expands thermally in an equal direction but the cover 9 does not expand thermally. The spacing between the material 5 and the cover 9 is thereby closed and the part of the material 5 except the exposed part can be shut off from the reactive gaseous atmosphere. If the temp. is lowered after the formation of the film, the material 5 restores the original size and can be therefore easily removed from the cover 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for forming a coating using a gas phase reaction method, particularly to local coating.

[Prior art]

Conventionally, it was the first device to form a film using a gas phase reaction.
There was something about diagrams. In the figure, ■ is the raw material gas,
(2) is a reactor, and (3) is an exhaust gas treatment device. FIG. 2 is a sectional view showing the inside of the reactor (21) in detail. In the figure, (41 is a heater, 15 is a workpiece, and 16 is a
; is a raw material gas introduction pipe, (71 is a shelf, +8) is an exhaust gas pipe.

Next, the conventional method of forming a film using gas phase reaction is shown in Figure 2 (
I will explain based on 2. The reactor (21
Until the inside reaches the film forming temperature, among the raw material gases, H2 gas and the like for preventing oxidation of the workpiece 15) are flowed from the raw material gas introduction pipe (6) into the reactor (21).Next, Reactor (2) When the inside reaches the film forming temperature, all the raw material gases are introduced into the reactor, the raw material gases undergo a chemical reaction, and a film is formed on the surface of the workpiece.In the reactor (2) The workpiece (51) is simply placed on a shelf (7) or suspended. Exhaust gas consisting of unreacted gas and reaction by-products is passed through an exhaust gas pipe (8).
), and after being treated by an exhaust gas treatment device, it is released into the air. Thereafter, the workpiece (51) is taken out after waiting for the temperature of the reactor (21) to cool down to around room temperature.

Conventional film formation using gas phase reactions is processed using the method described above, so the entire workpiece is coated, and in order to create locally uncovered areas, after the film formation process, for example, lapping is performed. This method requires post-processing such as removing the coating, which takes time, and has the disadvantage of increasing processing costs.

[Summary of the invention]

This invention was made to eliminate the drawbacks of the conventional methods as described above, and is a method for forming a film on the surface of a workpiece using a gas phase reaction, in which a non-coated part is left on the workpiece. By using a cover to cover the material, the material of the cover is such that the gap between the workpiece and the cover population is closed during film formation due to the difference between the thermal expansion coefficient of the workpiece and the cover. The purpose is to perform local coating in a short time and at low cost without post-processing.

[Embodiment of the Invention] FIG. 3 is a partial sectional view mainly showing a workpiece and a cover according to an embodiment of the invention.

In the figure, consider the case where a coating is to be formed only on the shaded area of a cylindrical workpiece (51). (91 is a cover for local coating, here it is made of an invar alloy, and the workpiece is It has an inner diameter slightly larger than the outer diameter.

Hereinafter, a description will be given according to the film forming process procedure. Shelf at room temperature (
7), there is a slight gap between the workpiece 151 and the cover (9). The inside of the furnace is heated by the heater, but only H2 gas is flowed until the reaction temperature (= = reached).At this time, the cylindrical workpiece (5
) thermally expands uniformly with respect to the shaft as the temperature rises, but the cover +91 made of invar alloy does not thermally expand and its inner diameter does not change. The amount of expansion of the workpiece (51) can be calculated in advance using the coefficient of thermal expansion. By using a cover (91) whose inner diameter is large by this amount of expansion, the film forming temperature can be adjusted as shown in Figure 4. At the workpiece (
In 5), the parts other than the exposed parts can be shielded from the reaction gas atmosphere. In this state, the reaction gas is flowed to form a film, and then the temperature of the reactor is lowered. When the temperature drops and the workpiece (51) is taken out, the dimensions of the workpiece +51 return to the original size as shown in Figure 3, and the cover (91) is easily removed.
It can be removed from 1.

In the above example, the cover is made of an invar alloy, so that the cover does not thermally expand and only the workpiece expands thermally. A combination may be used in which the workpiece and the cover are closed during film formation due to the difference in thermal expansion coefficient between the workpiece and the cover. Note that since the portion of the cover that contacts the workpiece is not coated, this cover can be used repeatedly.

〔Effect of the invention〕

As described above, according to the present invention, in the method of forming a film on the surface of a workpiece using a gas phase reaction, a cover is used for the workpiece to cover the non-coated part, and the material of the cover is as described above. Since we used a material that closes the gap between the workpiece and the cover during film formation due to the difference in thermal expansion coefficient between the workpiece and the cover, post-processing can be omitted, resulting in a short and inexpensive process. This has the effect of enabling local coverage.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional film forming apparatus using a gas phase reaction, Fig. 2 is a partial sectional view showing a reactor of a conventional film forming apparatus using a gas phase reaction, and Fig. 3 is a block diagram of a conventional film forming apparatus using a gas phase reaction. FIG. 4 is an enlarged cross-sectional view of the inside of the furnace at room temperature, mainly showing the workpiece and cover according to one embodiment of the present invention, and FIG. FIG. 2 is an enlarged sectional view of the inside of the furnace. 111... Raw material gas, (21... Reactor, (31...
...Exhaust gas treatment system fil! , 141... heater, (5
1...Workpiece, (91...Cover) The same reference numerals in the drawings indicate the same or equivalent parts. Agent: Masuo Oiwa Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a method of forming a film on the surface of a workpiece using a gas phase reaction, a cover is used for the workpiece to cover the non-coated parts, and the material of the cover is determined by the coefficient of thermal expansion of the workpiece and the cover. A method for forming a film using a gas phase reaction, characterized in that a material is used that closes a gap between the workpiece and the cover material during film formation due to a difference in thermal expansion coefficients.