JP2002249873A - Film forming method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film forming method, and an apparatus which enables film excellent in adhesion and has high dimensional accuracy forming. SOLUTION: This film forming method and device is provided with a vacuum chamber 1 which has an exhaust system 2 and a gas supply system 3, a plasma source 4 which generates plasma in the vacuum chamber 1, a bias power source 9 which applied a bias voltage to base bodies 10, a means 11 which monitors components generated by sputter cleaning and a controller 12 which controls the operation so as to selectively perform the sputter cleaning of the surface of the base bodies 10 and the film forming operation which forms a thin film on the surface of the base bodies. Further, this film forming method and device is constituted so as to stop the sputter cleaning and perform the film forming operation when the components generated by the sputter cleaning disappears and, at the same time, control a film forming time according to the time taken for the sputter cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a functional film such as a wear-resistant film on the surface of a mechanical part or the like.

[0002]

2. Description of the Related Art A conventional film forming method and apparatus will be described with reference to FIG. In FIG. 4, reference numeral 21 denotes a vacuum chamber, which includes an exhaust system 22 and a gas supply system 23. Reference numeral 24 denotes a plasma source for generating plasma, which in the illustrated example is formed of a coil disposed in the vacuum chamber 21 and is connected to a high-frequency power supply 25. Reference numeral 26 denotes a solid source for film formation, which emits metal atoms into the vacuum chamber 21 by sputtering or evaporation. In this conventional example, Ti is used as the metal. A power source 27 is connected to the solid source 26,
Energy required for sputtering and evaporation is supplied. 30
Is a substrate, which is placed on a support 28. Support stand 28
Is connected to a bias power supply 29 so that a bias voltage can be applied to the base 30 through the support 28.

Next, the operation will be described. The substrate 30 in this conventional example is a mechanical part made of an iron-based alloy used for a sliding portion, and the surface treatment is performed by forming a TiN film on the surface of the substrate 30 to improve wear resistance. It is assumed that. The film forming process includes a first step of removing an oxide film on the surface of the substrate 30 to improve the adhesion between the film and the substrate, and a second step of forming a TiN film.

First, the operation of the first step will be described. Argon gas is introduced from the gas supply system 23 and exhausted simultaneously from the exhaust system 22 to a predetermined pressure state.
When the power is supplied to the plasma source 24, the plasma P is generated. Next, a bias voltage is applied to the support 28 and the base 30 by the bias power supply 29.

As a result, the charged particles in the plasma P are accelerated by the bias voltage applied to the base 30, and collide with the base 30. The oxide film on the surface of the base 30 is removed by sputtering by the energy. This step is called sputter cleaning. The range of the thickness of the oxide film on the surface of the substrate 30 has been examined in advance, and
When the sputter cleaning is performed for a time sufficient for completely removing the oxide film on the surface of the first step, the first step is completed.

Next, the operation of the second step will be described. After the first step, when nitrogen is introduced from the gas supply system 23 and exhausted from the exhaust system 22 to a predetermined pressure state, and the high-frequency power supply 25 supplies power to the plasma source 24, plasma P is generated. Next, the power source 27 is turned on to supply energy to the solid source 26. Then, Ti
The atoms are released into the vacuum chamber 21 and the vacuum chamber 2
The Ti atoms released into 1 are ionized by the plasma P.

Next, a support 28 is supplied by a bias power supply 29.
Then, a bias voltage is applied to the base 30. The ionized Ti and nitrogen are attracted to the base 30, and a TiN film is formed on the surface of the base 30. After film formation for a certain period of time,
The step ends. Since the surface of the base 30 is cleaned in the first step, the formed TiN film and the base 30 have good adhesion.

As described above, the surface of the substrate 30 is subjected to a surface treatment having wear resistance. Substrate 30 after film formation
Is taken out, and the undeposited substrate 30 is set in the vacuum chamber 21.

[0009]

However, in the above-mentioned conventional method, there is a problem that the amount of the substrate 30 removed by cleaning varies depending on the state of the surface of the substrate 30, and the dimensions after film formation are not stable. This is because, when a group of substrates 30 that are simultaneously subjected to film formation processing is called a lot, the oxidation state of the surface of the substrate 30 varies depending on the manufacturing conditions and storage method of the substrate 30 for each lot, and the material of the substrate 30 and the oxide film This is due to the fact that the sputter rate differs between

[0010] For example, if a condition in which the oxide film can be removed by 0.5 μm in the first step is used for a lot having an oxide film of 0.2 μm, the oxide film of 0.2 μm and the substrate of 0.4 μm are removed. A dimensional change of 0.6 μm occurs. That is, a dimensional variation of 0.1 μm occurs between the lot of the oxide film 0.2 μm and the lot of the oxide film 0.5 μm. In the second step, a film having a constant thickness, for example, 5 μm is formed, so that this variation remains as a dimensional variation of the processed component. This problem is particularly important in the processing of mechanical parts and the like that require dimensional accuracy.

An object of the present invention is to provide a film forming method and apparatus capable of forming a film with good adhesion and high dimensional accuracy of a substrate in view of the above conventional problems.

[0012]

According to the film forming method of the present invention, a plasma is generated in a vacuum chamber, the surface of the substrate is sputter-cleaned by ions in the plasma, and then a thin film is formed on the surface of the substrate. In the method, a component generated by sputter cleaning is monitored at the time of sputter cleaning, the sputter cleaning is stopped when the component disappears, and the film forming time is changed according to the time taken for sputter cleaning,
Sputter cleaning is performed only for the required time according to the state of the substrate, so that a film with good adhesion can be formed by proper sputter cleaning, and even if the dimensional change due to sputter cleaning is different, processing is performed by forming an amount that corrects the change. A film having high dimensional accuracy can be formed on a subsequent component.

The monitoring of the components generated by the sputter cleaning can be performed by emission spectroscopy or mass spectrometry.

Further, the film forming apparatus of the present invention comprises a vacuum chamber provided with an exhaust system and a gas supply system, a plasma source for generating plasma in the vacuum chamber, a power supply for applying a bias voltage to the substrate, and a sputtering system. A means for monitoring components generated by the cleaning; and a controller for selectively performing sputter cleaning of the surface of the substrate and a film forming operation for forming a thin film on the surface of the substrate. When the generated components disappear, the sputter cleaning is stopped and the film forming operation is performed, and the film forming time is controlled in accordance with the time taken for the sputter cleaning,
The effect can be obtained by implementing the above-described film forming method.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a film forming method and apparatus according to the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a vacuum chamber;
An exhaust system 2 and a gas supply system 3 are provided. Reference numeral 4 denotes a plasma source for generating plasma, which in the illustrated example is composed of a coil disposed in the vacuum chamber 1 and is connected to a high-frequency power supply 5. Reference numeral 6 denotes a solid source for film formation, which emits metal atoms into the vacuum chamber 1 by sputtering or evaporation. In the present embodiment, Ti is used as the metal. A power source 7 is connected to the solid source 6 to supply energy required for sputtering and evaporation. Reference numeral 10 denotes a base, and a support 8
Is placed on top. A bias power supply 9 is connected to the support 8 so that a bias voltage can be applied to the base 10 through the support 8.

Reference numeral 11 denotes monitoring means for monitoring components generated by sputter cleaning, and the detection signal is input to the controller 12. The monitoring means 11 may be based on emission spectroscopy,
Mass spectrometry may be used.

The controller 12, as shown in FIG.
The power supply 7 and the power supply 7 are controlled according to a command from the operation unit or the host controller or a detection result from a detection unit such as the monitoring unit 11.
The control unit 13 that controls each operation unit of the overall apparatus such as the bias power supply 9, the timer 14 that measures the sputter cleaning time, and the thickness of the oxide film that has been sputter cleaned with reference to the oxide film thickness-sputter time table 16. Oxide film thickness calculating means 15 for calculating, a desired film thickness provided by the control unit 13 and the calculated oxide film thickness, and a film formation time calculation for calculating the film formation time with reference to the film thickness-film formation time table 18 Means 17 are provided. The oxide film thickness-sputter time table 16 and the film thickness-film formation time table 18 are prepared and stored in advance.

Thus, the controller 12 stops the sputter cleaning by detecting the disappearance of the component generated by the sputter cleaning based on the signal from the monitoring means 11, and also sets the time from the start to the end of the sputter cleaning. The dimensions of the substrate 10 measured and reduced by the cleaning time are determined, and the film forming time is determined so that the dimensions after the film formation have a desired value.

Next, the operation will be described. The base 10 in the present embodiment is a mechanical part made of an iron-based alloy used for a sliding portion. The surface treatment is performed by forming a TiN film on the surface of the base 10 to improve wear resistance. It is assumed that. The film forming process includes a first step of removing an oxide film on the surface of the substrate 10 to improve the adhesion between the film and the substrate, and a second step of forming a TiN film.

First, the operation of the first step will be described. Argon gas is introduced from the gas supply system 3 and simultaneously the exhaust system 2
When the air is further exhausted to a predetermined pressure state and the power is supplied to the plasma source 4 by the high frequency power supply 5, the plasma P is generated. Next, the support 8 and the base 10 are
Is applied with a bias voltage.

As a result, the charged particles in the plasma P are accelerated by the bias voltage applied to the substrate 10, and collide with the substrate 10. The oxide film on the surface of the substrate 10 is removed by sputtering by the energy. The components removed by sputtering are monitored by monitoring means 1.
1 and the sputter cleaning of the first step is completed by its disappearance.

FIG. 3 shows an example in which the emission intensity of oxygen that has been beaten out of the substrate 10 by sputtering and excited by the plasma P is monitored. Monitoring was performed at 777.1 nm, 777.4 nm, 777.5 nm.
At the wavelength of A is a monitoring curve at the time of sputtering the oxide film 0.2 μm, B is a monitoring curve at the time of sputtering the oxide film 0.5 μm, and the time Ta
At Tb and Tb, oxygen disappears, and it can be determined that cleaning has been completed.

Next, the operation of the second step will be described. After the end of the first step, when nitrogen is introduced from the gas supply system 3 and exhausted from the exhaust system 2 to a predetermined pressure state, and the high-frequency power source 5 supplies power to the plasma source 4, plasma P is generated. Next, the power source 7 is turned on and the solid source 6 is turned on.
Supply energy to Then, Ti atoms are released into the vacuum chamber 1 and T atoms released into the vacuum chamber 1
The i atoms are ionized by the plasma P.

Next, a bias voltage is applied to the support 8 and the base 10 by the bias power supply 9. Ionized T
i and nitrogen are attracted to the base 10 and a TiN film is formed on the surface of the base 10. Here, the film formation time is reduced by the substrate 10 reduced by the sputter cleaning in the first step.
Is determined, and the controller 12 adjusts the dimension after film formation to a desired value.

For example, if the time required for the sputter cleaning is Ta, it is determined that the thickness of the oxide film is 0.2 μm, and a 5.2 μm film is formed in the second step. Also, the time taken for sputter cleaning is Tb
In this case, it is determined that the thickness of the oxide film is 0.5 μm, and a 5.5 μm film is formed in the second step. The relationship between the time required for the sputter cleaning and the thickness of the oxide film is taken in advance. The same applies to the relationship between the film formation time and the film thickness in the second step. As described above, the surface of the substrate 10 is subjected to a surface treatment having wear resistance.

In the above-described embodiment, an example has been described in which the plasma source 4 is composed of a coil. However, if the plasma can be generated and maintained by an AC or DC bias power supply 9 for biasing the support 8, Can be considered as a plasma source.

[0028]

According to the film forming method and apparatus of the present invention, the components generated by sputter cleaning during sputter cleaning as described above are monitored, and when the components disappear, the sputter cleaning is stopped. Since the film formation time is changed according to the time taken for cleaning, it is possible to properly perform sputter cleaning only for the required time according to the state of the substrate, and to form a film having good adhesion,
Further, even if the dimensional change due to sputter cleaning is different, by forming a film by an amount that corrects it, a film having high dimensional accuracy of the processed component can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a film forming apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a controller in the embodiment.

FIG. 3 is an explanatory diagram of a monitoring state in the embodiment.

FIG. 4 is a schematic configuration diagram of a conventional film forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Exhaust system 3 Gas supply system 4 Plasma source 9 Bias power supply 10 Substrate 11 Monitoring means 12 Controller

Claims (4)

[Claims] In a film forming method, a plasma is generated in a vacuum chamber, and a surface of a substrate is sputter-cleaned by ions in the plasma, and then a thin film is formed on the surface of the substrate. A sputter cleaning is stopped when the component disappears, and a film forming time is changed according to a time taken for the sputter cleaning. 2. The film forming method according to claim 1, wherein the components generated by the sputter cleaning are monitored by emission spectroscopy. 3. The film forming method according to claim 1, wherein the components generated by the sputter cleaning are monitored by mass spectrometry. 4. A vacuum chamber provided with an exhaust system and a gas supply system, a plasma source for generating plasma in the vacuum chamber, a power supply for applying a bias voltage to the substrate, and monitoring of components generated by sputter cleaning. And a controller for selectively performing a sputter cleaning of the surface of the substrate and a film forming operation for forming a thin film on the surface of the substrate. A film forming apparatus configured to stop the sputter cleaning to perform a film forming operation and to control a film forming time according to a time taken for the sputter cleaning.