JPH10298737A - Contamination preventing material for thin film forming device, thin film forming device and formation of thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the peeling of a film forming material from a contamination preventing agent even in a high temp. environment and to reduce the generation of particles, as metal foil used for a contamination preventing material, by selecting the material having a thermal expansion coefficient between the thermal expansion coefficient of the film forming material and the thermal expansion coefficient of the material in the part not required in film formation. SOLUTION: A contamination preventing material for the thin film forming device is formed by the material having a thermal expansion coefficient in the range between the thermal expansion coefficient of a film forming material and the thermal expansion coefficient of the member not required in film formation in the device. As this material, metal foil or bellows-shaped metal foil or metal foil in which plural projecting and recessing parts are formed by embossing is used. Preferably, the surface roughness Ra of this metal foil is regulated to 1 μm and the thickness to 10 to 500 μm. The forming of the metal foil into the shape of bellows is executed by forming by roll forming or the like. The formation of plural projecting and recessing parts by the embossing is executed by forming such as press working, roll forming or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus and a thin film forming method in which a pollution preventing material for preventing contamination and generation of particles in a device in the thin film forming apparatus is provided. is there.

[0002]

2. Description of the Related Art Today, thin films for electrodes and diffusion barriers of integrated circuits, magnetic thin films for magnetic recording media, and ITO for liquid crystal display devices are used.
2. Description of the Related Art Thin film forming techniques such as a sputtering method and a CVD method are used for forming many thin films such as a transparent conductive film. Current,
Such a thin film forming technique has been established as a mass production technique, but has a drawback that particles generally called particles are deposited on the formed film, and this problem has recently been highlighted.

[0003] The particles refer to particles obtained by depositing clustered fine particles of a coating material on a substrate. Many of the clustered fine particles have a diameter as large as about several micrometers, and these particles are deposited on the substrate. Then, for example, in the case of an LSI, a problem such as a short circuit of a wiring or a disconnection is caused, which causes an increase in a defective rate. These particles are caused by various factors such as those caused by the thin film forming means itself and those caused by contamination of the thin film forming apparatus, and various measures have been taken to investigate and reduce the causes. It is the current situation.

[0004] For example, as a particle originating from a sputtering apparatus, a sputtered thin film adhered to an internal device around a substrate or a target or an inner wall (furnace wall) of a chamber or the like peels off and scatters and deposits on the substrate to cause a contamination source. Is one of the major factors. In order to prevent particles due to such re-peeling of adhered substances, it is necessary to keep equipment and inner walls in the sputtering apparatus clean at all times.

However, it is actually very difficult to keep such internal equipment and the like clean at all times to prevent re-peeling. Measures that have been taken in the past include physical roughening of the equipment surface in the apparatus and the use of antifouling materials with disposable foils. In the former case, for example, in the case of a sputtering device, the surface is roughened by a method such as sand blasting, Al thermal spraying, Mo thermal spraying on the internal equipment around the substrate, the internal equipment around the target and the shutter, and the thin film formed on those internal equipment is formed. This is a method of preventing the scattering substance film from peeling. This method becomes ineffective when the thickness of the adhered product increases, the parts must be replaced frequently, and the method of regenerating the internal equipment is complicated. In the latter case, a flat Al foil or Fe foil is attached to an internal device or the like in advance, and the thin film is removed after the formation of the thin film. This is considered to be able to keep the internal device and the like in a clean state. . However, the thin film forming scattered material film deposited on these disposable foils is easy to peel off,
Particles on the substrate were still generated. When this disposable foil is used, the peeling phenomenon becomes more prominent as the thickness of the scattered substance is larger, and the product is formed of silicide or IT.
It is more likely to occur in the case of ceramics such as O (indium-tin oxide). In order to prevent this peeling, the foil had to be replaced frequently, and the operability of forming a thin film was significantly deteriorated.

On the other hand, there has been proposed a corrugated electrolytic copper foil, an electrolytic copper foil having a plurality of irregularities formed by embossing, an electrolytic Ni foil, or an electrolytic Ni foil having a plurality of irregularities formed by embossing. In recent years, for example, in the case of sputtering equipment, internal equipment and the like have been exposed to higher temperatures due to an increase in sputtering power. Insufficient strength has resulted in the tearing of the foil or the thin film-forming scattered substances deposited on the foil being easily peeled off, so that the expected effect of reducing particles cannot be obtained.

Conventionally, the peeling of the scattered substances forming the thin film has been caused by the film stress of the deposited film itself. However, in recent years, the film stress of the film itself has been considerably relaxed due to the film formation in a high temperature environment. It is considered that the difference in the thermal expansion coefficient between the thin film and the material to which the thin film adheres and the temperature cycle resulted in the occurrence of peeling due to the generated thermal stress. In other words, when a thin film-forming scattered substance adheres to the surface of an internal device made of a material such as stainless steel at a high temperature, the thermal expansion coefficient of the film is generally smaller than that of stainless steel (particularly in the case of a ceramic film). After film deposition below, when the temperature decreases, the amount of shrinkage of the device surface becomes larger than the amount of shrinkage of the film-formed product, causing stress and causing film peeling.

When a metal thin film is disposed on the surface of an internal device,
The stress that causes film peeling and the stress that breaks the metal foil are affected by the difference in the thermal expansion coefficient between the metal foil and the internal device material, in addition to the difference in the thermal expansion coefficient between the metal foil and the film. That is, since the metal foil is fixed to the surface of the internal device by some method, a stress is generated due to a difference in thermal expansion like the film-metal foil. Therefore, in order to avoid peeling of the film and breakage of the metal foil, it is necessary to consider a combination of the three components of the film, the metal foil, and the material of the internal device.

[0009]

In order to solve the above-mentioned problems, the present inventors have prevented contamination in the thin film forming apparatus even in a high temperature environment in recent years, and have caused the re-peeling of scattered products. As a result of intensive studies as a material for suppressing particles, metal foil made of a material having a coefficient of thermal expansion within a range between a film forming material and a member of a portion of a thin film unnecessary part in the apparatus does not prevent contamination. It was found that it was very effective as a material.

That is, the present invention provides: In a contamination prevention material for a thin film forming apparatus, a metal foil made of a material having a coefficient of thermal expansion in a range between a coefficient of thermal expansion of a film and a coefficient of thermal expansion of a member of a thin film unnecessary part in the apparatus or Antifouling material for thin film forming equipment consisting of bellows-shaped metal foil or metal foil with multiple irregularities formed by embossing

2. Surface roughness R of metal foil used as pollution control material
a is 1 μm or more, wherein the contamination preventing material for a thin film forming apparatus according to 1 above,

3. The thickness of the metal foil used as a pollution control material is 10 ~
3. The antifouling material for a thin film forming apparatus according to the above 1 or 2, wherein the thickness is 500 μm.

4. The contamination preventing material for a thin film forming apparatus according to any one of the above 1 to 3 is disposed at a portion where the thin film is not required in the apparatus to prevent contamination of equipment in the apparatus and generation of particles during film formation. Thin film forming equipment

5. The contamination preventing material for a thin film forming apparatus according to any one of the above 1 to 3 is disposed at a portion where no thin film is formed in the apparatus to prevent contamination of equipment in the apparatus and generation of particles during film formation. It is intended to provide a method for forming a thin film.

By using the metal foil having a specific coefficient of thermal expansion according to the present invention as a contamination preventive material, contamination inside the thin film forming apparatus is eliminated and equipment such as a shutter, a substrate shield, a magnetic shield, and an inner wall is removed. The generation of particles due to the peeling off of the adhesion products of
It has become possible to form a good thin film.

In the present invention, the thin film forming means is a sputtering method, a thermal decomposition method, a hydrogen reduction method, a transport reaction method, a chemical vapor deposition method (CVD) such as a plasma CVD, a low pressure CVD, or a vapor deposition method. Epitaxy (VP
E), physical vapor deposition methods such as vacuum vapor deposition method and ion beam method (P
VD) and the like, and the present invention includes these. The metal foil used as the pollution control material of the present invention can be referred to as a particle getter in the sense that it captures particles that are the source of particles and prevents scattering.

The metal foil to be used for the anti-pollution material of the present invention is selected according to the thermal expansion coefficient of the film forming material and the thermal expansion coefficient of the material in the portion where film formation is unnecessary. That is, it is necessary to select a metal material having a coefficient of thermal expansion between the coefficient of thermal expansion of the film-forming material and the coefficient of thermal expansion of the material of the portion not requiring film-forming. This is because the stress that causes film peeling and the stress that breaks the metal foil are due to the difference in the coefficient of thermal expansion between the film deposited on the pollution control material and the metal foil, and the material of the metal foil and the unnecessary part of the film. This is because both are affected by the difference in the coefficient of thermal expansion. If the coefficient of thermal expansion of the metal foil is out of the range between the film forming material and the material of the film unnecessary portion, the difference in the coefficient of thermal expansion between the metal foil and the film forming material or the film unnecessary member becomes too large. This is not preferable because the stress is increased and the film is peeled or the metal foil is broken. Here, the case where the coefficient of thermal expansion of the metal foil is the same as that of one of the film-forming material and the member not requiring film-forming (for example, the case where a metal foil of the same material as the film-forming material is used) is included in the present invention.

Examples of special treatments to be formed on the surface of the metal foil include bellows, forming a plurality of irregularities by embossing, blasting, pickling, and plating of the surface of the metal foil. Those that increase the surface roughness are exemplified. By performing such treatment on the metal foil, the metal foil is given flexibility, and in the above case, it is possible to expand and contract in the wavy direction. ) And possessing a shape-correcting effect (improving a certain degree of rigidity), it is possible to prevent abnormal deformation due to warpage of the pollution control material itself and peeling of adhered products.

The metal foil is formed into a bellows shape by forming such as roll forming. It is desirable that the wave height is 0.1 to 5 μm and the bending angle θ is 10 ° to 150 ° (more desirably, 30 ° to 100 °), but the shape of the wave does not need to be particularly limited.

In order to form a plurality of irregularities on the metal foil by embossing, the metal foil is formed by forming such as press working and roll forming. Various shapes such as random unevenness and regular unevenness are conceivable, but the shape of the unevenness may be selected according to the shape of the device and need not be particularly limited.

The method for roughening the surface roughness of the metal foil includes blasting with SiC, alumina beads, zirconia beads and the like, pickling with a hydrogen fluoride solution, etching, plating and the like. It does not limit. By performing such a roughening treatment, the surface area of the metal foil is greatly increased, and the effect of capturing particles serving as a particle generation source and preventing scattering is also increased.

The thickness of the metal foil serving as the contamination preventing material is 10 to 50.
Although a thickness of 0 μm can be used, it is preferably 30 to 250 μm, and particularly preferably 70 to 150 μm. If the metal foil is too thin, the strength of the metal foil itself is small and rigidity is insufficient, and it is difficult to bend and emboss in a bellows shape. Also,
If the metal foil is too thick, the rigidity becomes too high with work hardening, the flexibility is lost, and the metal foil is liable to peel off from the adhered product, and particles are generated.

The surface roughness of the metal foil serving as a contamination preventing material is required to be 1 μm or more in terms of Ra in order to capture particles serving as particles and prevent the particles from hardening. Preferably, Ra should be in the range of 1 to 7.5 μm. Due to the presence of the projections due to the roughness, the adhesion to the film formed by the attachment of the scattered substance due to the anchor effect is improved, and the occurrence of peeling can be greatly reduced.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. (Example 1) Using a high-purity Ti target (3 inches in diameter), a contamination preventive material made of various metal foils shown in Table 1 was mounted on a SUS substrate, a Ti substrate, and a silicon nitride substrate of a sputtering apparatus, and placed in a nitrogen atmosphere. Reactive sputtering was performed. By heating the substrate, the temperature of the metal foil during film formation
The temperature was adjusted to 400 ° C. Table 1 shows the results of taking out and observing the foil after the end of sputtering.

[0025]

[Table 1]

(Example 2) Using a high-purity ITO target (3 inch diameter), a contamination preventive material composed of various metal foils shown in Table 2 was mounted on a SUS substrate, a Ti substrate and a silicon nitride substrate of a sputtering apparatus. Sputtering was performed. The temperature of the metal foil during film formation was adjusted to 250 ° C. by heating the substrate. Table 2 shows the results of taking out and observing the foil after the end of sputtering.
Shown in

[0027]

[Table 2]

In the examples of the present invention, the film formed after sputtering did not peel off from the contamination preventive material made of metal foil.
Also, almost no deformation or breakage of the metal foil after the sputtering test was observed. On the other hand, in the comparative example, the film was often peeled off after the sputtering, and deformation or breakage was observed in the metal foil after the sputtering test.

[0029]

According to the present invention, a metal foil or bellows made of a material having a coefficient of thermal expansion in a range between the coefficient of thermal expansion of a film and the coefficient of thermal expansion of a member not requiring thin film formation in a thin film forming apparatus. The use of a metal foil or a metal foil having a plurality of concavities and convexities formed by embossing makes it possible to suppress peeling of a film from the metal pollution control material even in a high-temperature environment. Therefore, by using the anti-contamination material of the present invention, it is possible to prevent the contamination inside the thin film forming apparatus, and to significantly reduce the generation of particles due to the detachment of the adhered products from the equipment inside the apparatus. It is possible to carry out thin film formation.

Claims (5)

[Claims] 1. A pollution control material for a thin film forming apparatus,
A plurality of metal foils or accordion-shaped metal foils made of a material having a coefficient of thermal expansion in a range between the coefficient of thermal expansion of a film and the coefficient of thermal expansion of a member of a thin film forming unnecessary part in the apparatus, or a plurality of metal foils formed by embossing. Anti-pollution material for thin film forming equipment consisting of metal foil with irregularities. 2. The antifouling material for a thin film forming apparatus according to claim 1, wherein the surface roughness Ra of the metal foil serving as the antifouling material is 1 μm or more. 3. The thickness of a metal foil serving as a pollution control material is 10 to 500.
The contamination preventive material for a thin film forming apparatus according to claim 1, wherein the thickness is μm. 4. The thin film forming apparatus according to claim 1, wherein the anti-contamination material for a thin film forming apparatus is disposed in a portion where no thin film is formed in the apparatus to prevent contamination of equipment in the apparatus and generation of particles during film formation. A thin film forming apparatus characterized in that: 5. The thin film forming apparatus according to claim 1, wherein the anti-contamination material for a thin film forming apparatus is disposed in a portion where no thin film is formed in the apparatus to prevent contamination of equipment in the apparatus and generation of particles during film formation. A thin film forming method.