JPH04202655A - Method for preventing pollution in thin film forming apparatus and pollution preventing material used therefor - Google Patents

Abstract

PURPOSE:To prevent the particle pollution in a thin film at the time of thin film forming and to prevent the pollution in the inside of a device and an apparatus by forming a mesh material on the surface of parts and thermal-spraying the surface with a metal. CONSTITUTION:A mesh material made of a metal is fitted to the inner face of a thin film forming device or apparatus parts in the device by spot welding or the like. This surface is thermal-sprayed with a metal such as Mo to form a metal sprayed deposit. This metal sprayed deposit has tight bonding strength with a mesh material, but does not has a bonding strength substantially with the surface of the deposited part therebelow and can easily peel the metal sprayed layer from the surface of the deposited part. Thus, the recycle of parts (place) which have been coated with the metal sprayed deposit is permitted. As for the metal sprayed deposit, because the capturing capacity for deposited matter reduces when it is accumulated to a degree above the standard, it is peeled at suitable intervals, and after its application to a mesh material once more, metal spraying is executed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to the prevention of contamination of the inner surface and internal equipment of a thin film forming apparatus such as a sputtering apparatus due to scattered adhesion substances, and thin film particle contamination due to re-peeling of the adhesion substances. The present invention relates to a method for preventing contamination and a material for preventing contamination of a metal sprayed film with a mesh used therein. INDUSTRIAL APPLICABILITY The present invention is useful for improving the quality of semiconductor devices and other devices by vapor phase growth, and for maintaining equipment and equipment therefor.

(Background of the Invention) Conventionally, vapor phase growth technology has been used to form many thin films, such as thin films for electrodes and diffusion barriers in integrated circuits, magnetic thin films for magnetic recording media, and ITO transparent conductive films for liquid crystal display devices. ing. Thin film formation techniques using this vapor phase growth technique include thermal decomposition, hydrogen reduction, disproportionation reaction, chemical vapor deposition such as plasma CVD, sputtering, vacuum evaporation, ion beam method, discharge gravity There are legal and other options.

Although such a thin film formation process using the vapor phase growth method has been established as a mass production technology, there is a problem of contamination of the internal walls of the device or equipment within the device due to gas vapor scattering to areas other than the thin film forming area, and furthermore, In recent years, the problem of coarse particles called "particles" accumulating on the formed thin film has been highlighted.

These "particles" refer to the accumulation of fine particles that clustered during thin film formation, and these are often as thick as several micrometers. Therefore, when they are deposited on a substrate, for example, In the case of LSIs, problems such as short circuits or disconnections occur in the wiring, which causes an increase in the defect rate.These particles are caused by various factors such as those caused by the thin film formation method itself and those caused by the coating equipment. The current situation is that various efforts are being made to investigate the cause and take measures to reduce it.

Particles caused by the thin film forming equipment mentioned above include thin films caused by dissipated raw material vapor adhering to the inner walls of the equipment (furnace walls) and equipment around the substrate, such as shutters and shield plates. One of the major factors is that it peels off again, scatters and accumulates on the substrate, becoming a source of contamination.

(Prior art) Therefore, for the purpose of maintenance of the apparatus and internal equipment, and to prevent particles caused by re-peeling of such adhered substances, it is necessary to keep at least the inner walls and equipment of the thin film forming apparatus clean at all times. .

However, it is actually difficult to keep these inner walls and equipment clean at all times, and it takes a lot of time to completely clean them, and there are some parts of the inner walls and equipment that cannot be cleaned. There is also.

For this reason, (1) Placing shielding plates in the form of flat plates, cylinders, or other shapes and replacing them as appropriate; (2) Physical roughening by forming a sprayed metal film on parts of the equipment where flying debris is likely to adhere. (3) attach disposable metal foils such as aluminum, iron, copper, etc. to the inner walls of the device and remove them after the thin film forming operation is completed; Measures have been taken to:

(Problem to be solved by the invention) Inside the thin film forming apparatus, there are relatively many parts that have complicated contours formed by combining steps and protrusions, and parts with complicated shapes, such as substrate shield plates, are used. There are many things. A shielding plate of a simple shape such as a flat plate is not very useful for such a part because it cannot cover the complex shape. The method of pre-forming a sprayed metal film on parts of equipment where flying debris is likely to adhere is useful for complex-shaped parts such as these, but if the amount of flying debris adheres above a certain level, the adhered thin film tends to peel off. Although it is necessary to re-form the sprayed film, it is extremely difficult to recycle the parts. Metal thermal spraying on the inner walls of the equipment is difficult to remove, so it cannot be repeated many times, and its useful life is short.

The use of metal foil is a very simple method, but the material of the metal foil is limited, and it is not necessarily useful in harsh conditions such as high temperatures, high melting point metal sputtering, and close proximity to the plasma generation site. do not have. Although metal foil is thin, it is easy to tear when bent or pressed along a complex shape, or when attached by spot welding or brazing, making it troublesome to handle. It has also been found that the thin film of scattered particles adhering to the foil is likely to be peeled off again.

In the case of complex parts, metal foil is produced by creating a mold according to the shape of the target part and press-forming using this mold. In the case of complex shapes, molding itself is impossible.

The object of the present invention is to be able to apply it to parts or parts with complex shapes inside a thin film forming apparatus, and to be able to easily remove them therefrom, while eliminating the drawbacks of metal foil in terms of durability, ease of handling, and ease of installation. The objective is to establish measures to prevent particle contamination of thin films during thin film formation and contamination of the inside of the device and equipment.

(Means for Solving the Problems) The metal sprayed film basically has an excellent ability to capture scattered adhering substances without peeling due to its rough surface properties, and can be formed from a heat-resistant material. In order to solve the above-mentioned problems while taking advantage of the advantages of this metal sprayed film, we came up with the idea of using a mesh material in combination with the metal sprayed film. It was found that when metal is thermally sprayed onto the surface of a adhered part, the sprayed film can be easily peeled off from the surface of the part when it is replaced, making it possible to recycle the part. A pollution prevention material in which a metal sprayed film with a mesh material, which is obtained by depositing a mesh material on a metal plate, thermally spraying a metal onto the mesh material, and then separating the metal sprayed film with a mesh material from a metal plate, etc., replaces metal foil. It has also been found that it is very useful as a metal spray coating.The metal spray coating with a mesh material can be formed into complex shapes. This combination solves the conventional problems.

Based on these findings, the present invention provides the following: l) In a thin film forming apparatus using vapor phase growth, in order to prevent contamination of the inner surface and internal equipment of the apparatus by scattered adherent substances and thin film particle contamination due to re-peeling of the adhered substances, A method for preventing contamination in a thin film forming apparatus, characterized in that a mesh material is applied to the surface of a target adhesion part, and a metal is thermally sprayed onto the surface of the adhesion part covered with the mesh material to form a metal sprayed film. ) In a thin film forming device using vapor phase growth, a mesh material is applied onto a metal plate, etc. in order to prevent contamination of the inner surface and internal equipment of the device by scattered adherent substances and thin film particle contamination due to re-peeling of the adhered substances. , spraying metal onto the mesh material, and then separating the metal sprayed film with the mesh material from the metal plate, etc., and attaching the metal sprayed film with the mesh material to the surface of the target attachment part in the thin film forming apparatus. 3) A method for preventing contamination in a thin film forming apparatus characterized by: and 3) preventing contamination of the inner surface and internal equipment of the apparatus by scattered adherent substances and thin film particle contamination due to re-peeling of the adhered substances in a thin film forming apparatus using vapor phase growth. The purpose of the present invention is to provide a contamination preventive material used for this purpose, which is characterized by being made of a metal sprayed film having a mesh material on one surface.

(Detailed Description of the Invention) The device for forming a thin film by vapor phase growth according to the present invention is a method for forming a thin film using a chemical method such as a thermal decomposition method, a hydrogen reduction method, a disproportionation reaction method, a transport reaction method, a plasma CVD method, or a low pressure CVD method. Vapor phase growth method (CV
D) refers to equipment that forms thin films using vapor phase epitaxy (VPE), sputtering, vacuum evaporation, molecular beam epitaxy (MBE), ion beam method, discharge polymerization, and other vapor phase growth methods. .

In such a vapor phase growth thin film forming apparatus, raw material vapor inevitably scatters to the surroundings other than the thin film forming part, and adheres to the inner walls, shutters, shields, and other equipment inside the apparatus.
It contaminates them and impairs their function, and the deposits are peeled off again, causing the particle contamination of the thin film described above. Therefore, in connection with the present invention, there is a double contamination problem: contamination of the device/equipment itself and particle contamination of the thin film.

Therefore, in the present invention, the surface of a part or region (referred to as an adhesion part) where flying debris tends to adhere is shielded to prevent flying debris from adhering there, and the debris that has adhered to itself is firmly captured so that it does not peel off. Contamination prevention methods are implemented to ensure that:

In the first method of the present invention, a mesh material made of a metal such as stainless steel or nickel is attached to the target inner surface of the device or a component in the device, such as a complex-shaped component such as a substrate shield plate, by spot welding or the like. The mesh size may be fine to some extent, for example, in the range of 200 to 400 meshes. Then, metal is thermally sprayed from above to form a metal sprayed film. In this case, in consideration of recycling (reproduction) of the target parts or parts, it is preferable that the target surface does not have irregularities like a sandblasted surface. If this is done, the metal sprayed film deposited on the mesh material will have strong bonding strength with the mesh material, but will have virtually no bonding strength with the surface of the attached part below, and the metal sprayed film will be bonded to the mesh material together with the mesh material. It can be easily peeled off from the surface of the attached part. Therefore, it becomes possible to recycle (regenerate) the parts (parts) covered with the metal sprayed film. Since the ability of the metal sprayed film to capture deposits decreases when the deposits accumulate above a certain level, the film is peeled off at appropriate intervals, and the metal spraying is performed again after applying the mesh material.

In the second method, a metal plate or the like made of aluminum or other suitable material is provided and the mesh material is secured thereon, for example by clamping the ends. In addition to the metal plate, a mold or the like may be used. The material of the mesh material and the mesh dimensions are the same as before. Then, metal is thermally sprayed from above to form a metal sprayed film. For the reasons stated above, the metal spray coating can be easily peeled off together with the mesh material. The peeled metal sprayed film with mesh is attached to the surface of the target part or part by spot welding or the like. The metal sprayed film with a mesh material has good flexibility and can be easily attached to a complex-shaped part. The mesh material performs a peeling function and a reinforcing function.

As described above, the present invention provides a contamination prevention material that is used to prevent contamination of the inner surface and internal equipment of the device by scattered adhesion substances and thin film particle contamination due to re-peeling of the adhesion substances, and a mesh material is coated on one surface. It is characterized in that the metal sprayed film is applied to the target surface either integrally or as a separate member.

The metal to be thermally sprayed is appropriately selected depending on the type of equipment and the installation location, but high melting point metals such as molybdenum and tungsten, nickel, aluminum, etc. are used. In particular, it is preferable to use a high melting point metal such as molybdenum or tungsten under severe conditions such as high temperatures, high melting point metal sputtering, and close proximity to the plasma generation site.

The thickness of the metal spray coating ranges from 200 to 300 μm and is produced by gas or plasma spraying. The thermal spraying conditions may be those for forming a normal thermal spray coating film. In order to enhance the ability to capture deposits, the surface is made to have an appropriate roughness.

Regarding the metal used, any method can be used as long as it provides a smooth surface condition to the extent that the sprayed film will not adhere. For example, sand vapor finishing is one useful method.

It is also beneficial to use two methods depending on the site within one device.

(Example 1) Substrate shield inside sputtering equipment After temporarily polishing its surface with sandpaper, a 300-mesh stainless steel mesh was attached by spot welding along the shield plate, and molybdenum was gas-sprayed on top of it. . Thermal spraying was carried out using an oxygen-acetylene burner at a pressure of 5 kg/+nm2 (compressed air). The thickness of the sprayed film was 200 to 300 LLm.

The substrate shield plate on which the molybdenum sprayed film was formed in this manner was set in a sputtering device, and W-Till* was formed by sputtering.

The W-Ti film sputtering conditions were as follows: Varnish batter power: 5.5 W/cm2Ar partial pressure/l
Distance between Pa shield and target: 15 mm W-Ti deposition rate: Approx. 25 μm/hr W -T
After applying the i-film to a thickness of 200 μm, the condition of the mesh mesh molybdenum film was investigated, and the amount of deformation was less than 1 mm, and no peeling was observed.

(Example 2) Using an aluminum mold, 3
A stainless steel mesh of 00 mesh was clamped and molybdenum was gas sprayed onto it. The thermal spraying conditions were the same as in Example 1.

The molybdenum-attached mesh could be easily peeled off. This was attached to a shield plate, which is a component inside a sputtering apparatus for forming a W-Ti film, by spot welding. After attaching a 200 μm W-Ti film under the same conditions as in Example 1, the state of the mesh molybdenum film was investigated, and the amount of deformation was less than 1 mm, and no peeling was observed.

(Comparative example) When attaching a rolled pure aluminum foil with a thickness of 200 μm to a substrate shield, it is impossible to bend it by hand and deform it in a tight state along the shape of the shield plate.
First, a mold was made to match the shape of the shield plate, and this mold was used to perform press working.

After attaching the aluminum foil molded product thus produced to the shield plate inside the sputtering device for forming a W-Ti film by spot welding,
- A Ti film was formed to a thickness of 200 μm by sputtering. The amount of deformation was 1 mm or more, and peeling of the film was observed.

When the outer shape of the shield plate is intricate and complicated, it is practically impossible to form the shield plate itself.

(Effects of the invention) A thin film that can be applied to parts or parts with complex shapes that are placed under harsh conditions inside a thin film forming apparatus, can be easily removed from there, and has excellent durability, ease of handling, and ease of installation. We succeeded in establishing measures to prevent particle contamination of thin films during formation and contamination of the inside of the device and equipment. The metal sprayed film contamination prevention material with a mesh material of the present invention has a greater degree of freedom in molding than conventional metal foils, is excellent in attaching and detaching, especially easy to attach, and is low in cost involved in attaching.

Claims (1)

[Claims] 1) In a thin film forming apparatus by vapor phase growth, in order to prevent contamination of the inner surface and internal equipment of the apparatus by scattered adherent substances and thin film particle contamination due to re-peeling of the adhered substances, target adhesion 1. A method for preventing contamination in a thin film forming apparatus, characterized in that a mesh material is attached to the surface of the part, and a metal is sprayed onto the surface of the attached part covered with the mesh material to form a metal sprayed film. 2) In a thin film forming device using vapor phase growth, a mesh material is coated on a metal plate, etc. to prevent contamination of the inner surface and internal equipment of the device by scattered adherent substances and thin film particle contamination due to re-peeling of the adhered substances. Then, the metal is sprayed onto the mesh material, and then the metal sprayed film with the mesh material is separated from the metal plate, etc., and the metal sprayed film with the mesh material is attached to the surface of the target attachment part in the thin film forming apparatus. A method for preventing contamination in a thin film forming apparatus, characterized in that: 3) In a thin film forming apparatus by vapor phase growth, it is a contamination prevention material used to prevent contamination of the inner surface and internal equipment of the apparatus by scattered adhering substances and thin film particle contamination due to re-peeling of the adhering substances. A pollution prevention material comprising a metal sprayed film having a mesh material.