JP2012026038A - Plasma treatment apparatus and surface treatment method for base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treatment apparatus and a surface treatment method for a base material capable of reducing production cost.SOLUTION: The plasma treatment apparatus is equipped with a chamber 1, a base material holder 3 arranged in the chamber 1 and supporting a base material 2, a gas introduction path connected to the chamber 1 and introducing treating gas for etching into the chamber 1, and a high-frequency power source 4 for supplying high-frequency output of 50 to 500 kHz into the chamber 1, and produces plasma of the treating gas for etching in the chamber 1 by the high-frequency output supplied from the high-frequency power source 4 to remove a surface layer of the base material 2.

Description

  The present invention relates to a plasma processing apparatus and a substrate surface treatment method, and more particularly, to a plasma treatment apparatus and a substrate surface treatment method capable of reducing production costs, and also capable of reducing production costs and adhesion to a substrate. The present invention relates to an improved plasma processing apparatus and a substrate surface processing method.

  The diamond-like carbon (DLC) film has excellent characteristics not found in other hard films such as high hardness, low friction, low wear, and chemically inert. As a method for forming the DLC film, an ion vapor deposition method, a plasma CVD (chemical vapor deposition) method, a sputtering method, or the like is often used.

  However, since the mass production technique of the DLC film manufacturing method described above has not been sufficiently established, the production cost is high and it is currently used for special purposes. Furthermore, since the DLC film has a high internal stress by any of the film forming methods described above, it often causes a problem due to its low adhesion strength. Therefore, if mass production technology that can produce a DLC film with excellent adhesion strength at a low cost can be established, it will be possible to reduce the price of the DLC film by improving the production efficiency, and the market for the DLC film is expected to expand. .

  Recently, as a base treatment for products that form DLC films, which are hard films, on dies, machine parts, tools, etc., there is a composite curing process that improves the adhesion strength of films by ion nitriding, radical nitriding, radical carburizing, etc. Widely practiced (see, for example, Patent Documents 1 to 3).

JP 2005-068499 A JP 2004-250746 A JP 2000-120870 A

  However, the above-described ion nitriding, radical nitriding, and radical carburizing require a long process, and a DLC film needs to be formed using a PVD apparatus or a CVD apparatus that is different from the base treatment. . That is, in these composite curing processes, it is necessary to install a plurality of processing apparatuses, and each processing apparatus requires a long time for evacuation, heating, evacuation, film formation, and cooling. As a result, the production cost increases.

  Further, as described above, in the conventional method for manufacturing a DLC film, a mass production technique has not been sufficiently established, so that the production cost becomes high. For example, the conventional technique has a problem that the production cost increases because the deposition speed of the DLC film is low. Further, since the DLC film formed by any of the film forming methods described above has a high internal stress, there is a problem that its adhesion strength is low.

  The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a plasma processing apparatus and a substrate surface processing method capable of reducing production costs. Another object of the present invention is to provide a plasma processing apparatus and a substrate surface treatment method that can reduce the production cost and improve the adhesion to the substrate.

  The advantage of the plasma CVD method is that plasma can be formed with a simple structure of a vacuum exhaust system, a high-frequency power source, and a raw material gas supply device, and a good film formation is possible. Maintenance is also easier compared to the PVD method. is there. However, in a plasma CVD apparatus, a DC power supply or a high frequency power supply having a frequency of 13.56 MHz is generally used. However, both of them have advantages and disadvantages and are not easy to use industrially. Therefore, if a high frequency power source having a frequency of 50 to 500 kHz that combines the properties of a DC power source and a 13.56 MHz high frequency power source is used, it is considered that it is easy to handle industrially and mass production is facilitated. In addition, since the ion implantation effect can be expected with a high frequency power source of 50 to 500 kHz, the surface modification of the substrate can be performed with the same power source.

  The conventional technology is a method of curing the surface of a substrate such as a mold, a machine part, a tool, etc., and the surface layer is etched and removed to form a nitrided layer, a carburized layer, a carbonitrided layer, etc. In order to perform a composite curing process for forming a DLC film on the surface of the substrate after performing the above, a plurality of processing apparatuses are required. For example, it is necessary to form the DLC film with a processing apparatus different from the processing apparatus used for the surface modification. The reason for using a plurality of processing devices in this way is to use different power sources in each processing device. On the other hand, in the processing apparatus of the present invention, it is possible to perform processing with one processing apparatus (that is, one power supply) by using a high frequency power source of 50 to 500 kHz, excellent adhesion strength and productivity, and high quality. A DLC film can be manufactured at low cost.

  Further, in the plasma processing apparatus of the present invention, etching processing, ion implantation processing, film forming processing, and ashing processing can be performed by changing processing conditions with a single power source of 50 to 500 kHz.

In order to solve the above-described problems, a plasma processing apparatus according to the present invention includes a chamber,
A substrate holder disposed in the chamber and holding the substrate;
A gas introduction path connected to the chamber and introducing a processing gas into the chamber;
A high frequency power supply for supplying a high frequency output of 50 to 500 kHz in the chamber;
Comprising
Plasma treatment of the substrate is performed by generating plasma of the processing gas in the chamber by a high frequency output supplied from the high frequency power source.

A plasma processing apparatus according to the present invention includes a chamber,
A substrate holder disposed in the chamber and holding the substrate;
A first gas introduction path connected to the chamber and introducing a processing gas for ion implantation into the chamber;
A second gas introduction path connected to the chamber and introducing a processing gas for film formation into the chamber;
A high frequency power supply for supplying a high frequency output of 50 to 500 kHz in the chamber;
Comprising
Plasma treatment of the substrate is performed by generating plasma of the processing gas in the chamber by a high frequency output supplied from the high frequency power source.

In the plasma processing apparatus according to the present invention, the ion implantation process gas is any one of a nitriding process gas, a carburizing process gas, a carbonitriding process gas, and a silicon ion implantation process gas. , The film forming process gas is a DLC film forming process gas,
The plasma treatment is performed by generating plasma of the one processing gas in the chamber and nitriding, carburizing, carbonitriding, or silicon ion implantation on the surface of the base material, and then processing the DLC film forming gas into the chamber. It is also possible to form a DLC film on the surface of the base material by generating a plasma.
According to the plasma processing apparatus, since the high-frequency power source of 50 to 500 kHz is used, the deposition rate of the DLC film can be increased as compared with the prior art, and as a result, the production cost can be reduced.
The DLC film forming process gas may be a gas containing silicon, and the DLC film formed on the surface of the base material may be a silicon-containing DLC film.

In the plasma processing apparatus according to the present invention, the ion implantation process gas is any one of a nitriding process gas, a carburizing process gas, a carbonitriding process gas, and a silicon ion implantation process gas. The film forming process gas is a silicon compound gas and a DLC film forming process gas,
In the plasma treatment, plasma of the one processing gas is generated in the chamber, and after nitriding, carburizing, carbonitriding, or silicon ion implantation of the surface of the substrate, the plasma of the silicon compound gas is introduced into the chamber. Generating a silicon compound film on the surface of the base material, generating plasma of the silicon compound gas and the DLC film forming process gas, and forming a silicon-containing DLC film on the silicon compound film It is also possible.

A plasma processing apparatus according to the present invention includes a chamber,
A substrate holder disposed in the chamber and holding the substrate;
A gas introduction path connected to the chamber and introducing the first and second silicon compound gases and the DLC film forming process gas into the chamber;
A high frequency power supply for supplying a high frequency output of 50 to 500 kHz in the chamber;
Comprising
The first silicon compound gas plasma is generated in the chamber by the high frequency output supplied from the high frequency power source to form a silicon compound film on the surface of the substrate, and then the high frequency power supplied from the high frequency power source is supplied. Plasma processing for generating a silicon-containing DLC film on the silicon compound film by generating plasma of the second silicon compound gas and the DLC film forming process gas in the chamber by an output is performed. .
The second silicon compound gas may be the same gas as the first silicon compound gas or may be a different gas.

  The plasma processing apparatus according to the present invention may further include a third gas introduction path that is connected to the chamber and introduces an etching process gas into the chamber.

  The plasma processing apparatus according to the present invention may further include a fourth gas introduction path that is connected to the chamber and introduces a processing gas for ashing into the chamber.

  In the plasma processing apparatus according to the present invention, the high-frequency power source may supply a high-frequency power source of 300 kHz or less.

  The surface treatment method for a substrate according to the present invention is a process of any one of a processing gas for etching, a processing gas for ion implantation, a processing gas for film formation, and a processing gas for ashing with a high frequency output of 50 to 500 kHz. Plasma treatment is performed on the surface of the base material by generating gas plasma.

A surface treatment method for a substrate according to the present invention includes a first step of performing ion implantation on a substrate by generating plasma of a process gas for ion implantation with a high-frequency output of 50 to 500 kHz,
A second step of forming a thin film on the substrate by generating plasma of a processing gas for film formation with a high-frequency output of 50 to 500 kHz;
It is characterized by comprising.

The substrate surface treatment method according to the present invention is a high-frequency output of 50 to 500 kHz of plasma of any one of a nitriding treatment gas, a carburizing treatment gas, a carbonitriding treatment gas, and a silicon ion implantation treatment gas. A first step of performing nitriding or carburizing or carbonitriding or silicon ion implantation of the surface of the substrate by
A second step of forming a DLC film on the surface of the substrate by generating plasma of a processing gas for DLC film formation with a high frequency output of 50 to 500 kHz;
It is characterized by comprising.
The DLC film forming process gas may be a gas containing silicon, and the DLC film formed on the surface of the base material may be a silicon-containing DLC film.
The substrate surface treatment method according to the present invention is characterized in that silicon ions are implanted into the surface of a substrate by generating plasma of a treatment gas for silicon ion implantation with a high frequency output of 50 to 500 kHz.
The substrate surface treatment method according to the present invention is characterized in that a silicon compound film is formed on the surface of a substrate by generating plasma of a silicon compound gas with a high frequency output of 50 to 500 kHz.

According to the substrate surface treatment method of the present invention, a silicon compound film is formed on the surface of a substrate by generating a plasma of the first silicon compound gas or a treatment gas for silicon ion implantation with a high frequency output of 50 to 500 kHz. A first step of forming a film or implanting silicon ions;
A second step of forming a silicon-containing DLC film on the silicon compound film or the substrate by generating a plasma of a second silicon compound gas and a DLC film forming process gas with a high frequency output of 50 to 500 kHz. When,
It is characterized by comprising.
Further, before the first step, a plasma of any one of a nitriding process gas, a carburizing process gas, a carbonitriding process gas, and a silicon ion implantation process gas is generated by a high frequency output of 50 to 500 kHz. It is possible to further comprise a step of performing nitriding, carburizing, carbonitriding, or silicon ion implantation on the surface of the base material.

  Moreover, in the surface treatment method for a substrate according to the present invention, the surface layer of the substrate is removed by generating plasma of an etching process gas with a high frequency output of 50 to 500 kHz before the first step. It is also possible to further include an etching process.

  Further, in the substrate surface treatment method according to the present invention, after the second step, an ashing step of removing the thin film by ashing by generating plasma of an ashing processing gas with a high frequency output of 50 to 500 kHz. Further, it can also be provided.

  As described above, according to the present invention, it is possible to provide a plasma processing apparatus and a substrate surface treatment method capable of reducing production costs. In addition, according to another aspect of the present invention, it is possible to provide a plasma processing apparatus and a substrate surface treatment method that can reduce the production cost and improve the adhesion to the base.

It is a block diagram which shows schematically the plasma processing apparatus by Embodiment 1 of this invention. It is a figure which shows the GDS analysis result of the base-material surface plasma-nitrided using a 250kHz high frequency power supply. It is a figure which shows the GDS analysis result of the base-material surface which carried out the plasma carburizing process using the 250kHz high frequency power supply. It is a figure which shows the influence of Knoop hardness of a DLC film | membrane, and the nitriding process of a base material. It is a figure which shows the influence of Knoop hardness of a DLC film, and the carbonitriding process of a base material. It is a figure which shows the result of having calculated | required the contact | strength intensity | strength of the DLC film and foundation | substrate in each of the presence or absence of nitriding treatment of a foundation | substrate, and the presence or absence of carbonitriding treatment using the scratch tester. It is a figure which shows the relationship between the friction coefficient which is a result of measuring the friction coefficient of each DLC film of the sample 31 without nitriding treatment, and the sample 32 with nitriding treatment, and a sliding distance. It is a figure which shows the relationship between the friction coefficient which is a result of measuring the friction coefficient of each DLC film of the sample 33 without a carbonitriding process, and the sample 34 with a carbonitriding process, and a sliding distance. It is a figure which shows the relationship between the friction coefficient of each of a silicon containing DLC film and an additive-free DLC film, and a slip distance. It is a figure which shows the GDS analysis result of the base-material surface which ion-implanted silicon using the high frequency power supply of 250 kHz.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram schematically showing a plasma processing apparatus according to Embodiment 1 of the present invention.

  This plasma processing apparatus has a processing chamber 1, and a base material holder 3 for holding a base material 2 is disposed in the processing chamber 1. A high frequency power source (RF power source) 4 of 50 to 500 kHz is connected to the base material holder 3 via a matching device (not shown), and the base material holder 3 also functions as an RF electrode. The high frequency power source 4 applies a high frequency to the base material 2 through the matching unit and the base material holder 3. That is, in this plasma processing apparatus, a high-frequency power source 4 supplies a high-frequency current of 50 to 500 kHz to the base material holder 3 through the matching device so as to generate plasma of the processing gas above the base material 2. It has become.

  In this embodiment, a high-frequency power source having a frequency of 50 to 500 kHz is used, but a high-frequency power source having a frequency of 300 kHz or less is more preferable, and a high-frequency power source having a frequency of 250 kHz or less is more preferable. When a high-frequency power source of 300 kHz or less is used, there is an advantage that matching can be achieved with a low-cost matching device using a matching transformer or the like. Further, when the frequency of the high-frequency power source is lower than 50 kHz, a problem that induction heating occurs in the base material occurs. Further, when the frequency of the high frequency power source exceeds 500 kHz, the bias applied to the base material is lowered, and there is a problem that it is difficult to form the insulator film.

  A heater 5 is disposed around the substrate holder 3, and the substrate 2 is heated by the heater 5. In addition, the base material 2 can use various materials and various shapes.

  The processing chamber 1 is provided with a gas inlet 10 for introducing a reaction gas. A gas introduction path (not shown) for introducing the reaction gas into the processing chamber 1 is connected to the gas introduction port 10. The gas introduction path has a gas pipe (not shown). The gas pipe is provided with a flow meter (not shown) for measuring the gas flow rate and a gas flow controller (not shown) for controlling the gas flow rate. Appropriate amounts of argon gas, nitrogen gas, methane gas, hydrocarbon gas, oxygen gas, and source gas are supplied into the processing chamber 1 from the gas inlet by the flow meter. The processing chamber 1 is connected to a vacuum pump 13 that evacuates the inside of the processing chamber 1. This pump is composed of a mechanical booster pump and a rotary pump that are inexpensive and easy to maintain, without using an expensive and troublesome turbo molecular pump or diffusion pump. A pump having such a simple configuration can only obtain a vacuum degree of about 1 Pa, but the method according to the present invention can produce a high-quality film even in such a low vacuum.

  The high-frequency power source of 50 to 500 kHz in the plasma processing apparatus combines the advantages of a DC power source and a high-frequency power source, and has the advantage of using an industrially easy-to-handle frequency of 50 to 500 kHz, and can be produced even at low vacuum. There is an advantage of superiority. In addition, in the case of a high frequency power source of 50 to 500 kHz, there is an advantage that the bias effect to the base material is enhanced as compared with the conventional high frequency power source of 13.56 MHz, and thereby, there is an advantage that low vacuum and high speed of the process can be realized. is there. This advantage leads to cost reduction.

  Next, a method for etching the substrate surface using the plasma processing apparatus of FIG. 1 will be described. In this plasma processing apparatus, for example, a high-frequency power source 4 having a frequency of 250 kHz is used, and argon gas is used as a processing gas.

  First, austenitic stainless steel (for example, SUS304, size: 60 mm × 100 mm × 1.5 mm) is prepared as the base material 2, and this base material 2 is subjected to ultrasonic cleaning in acetone for 30 minutes, and then the base material is prepared. Mount on the holder 3.

  Next, the substrate 2 is heated to 120 ° C. by the heater 5, the inside of the processing chamber 1 is exhausted to 1 Pa or less by the vacuum pump 13, and argon gas is introduced into the processing chamber 1 from the gas inlet 10 at a flow rate of 60 cc / min. To do. Next, an argon plasma is formed above the base material 2 by supplying a high frequency current of 250 kHz to the base material holder 3 using the high frequency power source 4 at an output of 300 W. Thereby, the surface of the base material 2 is ion-etched by the action of strong ions, and the oxide layer on the surface of the base material 2 is removed. The etching process time is 20 minutes.

  Generally, the outermost surface of stainless steel is covered with an oxide layer mainly composed of chromium oxide. In order to remove the oxide layer, a reduction removal method using active hydrogen gas or a pickling method using concentrated nitric acid is performed. These removal methods are dangerous to handle and require post-treatment. Also, conventional ion etching using a high frequency power supply with a frequency of 13.56 MHz cannot remove the oxide (oxide film) of stainless steel. On the other hand, in this embodiment, since it is strong ion etching using a high frequency power source of 50 to 500 kHz, the oxide film on the surface of the stainless steel substrate can be removed by a plasma etching method that is safe and does not require post-processing. It becomes possible.

(Embodiment 2) Nitriding treatment Hereinafter, a surface treatment method for a substrate according to Embodiment 2 of the present invention will be described. In this surface treatment method for a base material, a nitride layer is formed on the surface of the base material by using the plasma processing apparatus shown in FIG. The high-frequency power source 4 in this plasma processing apparatus uses, for example, a frequency of 250 kHz, and the processing gas is nitrogen gas, ammonia gas, a mixed gas of ammonia and hydrogen, or the like.

  First, the substrate 2 made of austenitic stainless steel similar to that in the first embodiment is subjected to ultrasonic cleaning in the same manner as in the first embodiment, and then the oxide layer on the surface of the substrate 2 is removed. Remove by etching.

  Thereafter, the temperature of the base material 2 is maintained at 120 ° C. by the heater 5, the pressure in the processing chamber 1 is maintained at 1 Pa or less by the vacuum pump 13, and nitrogen gas is processed from the gas inlet 10 at a flow rate of 60 cc / min. Introduce into chamber 1. Next, a high frequency current of 250 kHz is supplied to the base material holder 3 using the high frequency power source 4 at an output of 300 W, thereby forming nitrogen plasma above the base material 2. Thereby, nitrogen is ion-implanted into the surface of the base material 2, and the surface of the base material 2 is nitrided. Since the 250 kHz high frequency power source 4 exhibits characteristics closer to direct current than the conventionally used high frequency power source having a frequency of 13.56 MHz, the ionized nitrogen collides with the substrate surface in a high energy state and is further injected. A nitride layer is formed on the substrate surface. In addition, since the oxide film on the surface of the stainless steel substrate is sufficiently removed by powerful ion etching, it is easy to form a high-quality nitride layer on the substrate surface.

  When the above-described nitriding treatment (ion implantation) on the substrate surface was performed for 120 minutes, a nitride layer having a Knoop hardness (load 10 gf) of HK924 was formed on the substrate surface. FIG. 2 shows the result of measuring the nitrogen distribution on the substrate surface at this time by GDS (glow discharge emission spectrometry).

  FIG. 2 is a diagram showing the relationship between the distance from the substrate surface and the concentration of the contained element. As shown in this figure, it was confirmed that nitrogen was distributed from the surface of the base material made of austenitic stainless steel to near 0.7 μm, and the base material surface was nitrided.

(Embodiment 3) Carburizing treatment A substrate surface treatment method according to Embodiment 3 of the present invention will be described below. This surface treatment method of a base material forms a carburized layer on the surface of the base material by using the plasma processing apparatus shown in FIG. The high-frequency power source 4 in this plasma processing apparatus uses a frequency of, for example, 250 kHz, and a processing gas (raw material gas) uses a hydrocarbon gas such as methane gas or acetylene and an argon gas.

  First, the substrate 2 made of austenitic stainless steel similar to that in the first embodiment is subjected to ultrasonic cleaning in the same manner as in the first embodiment, and then the oxide layer on the surface of the substrate 2 is removed. Remove by etching.

  Thereafter, the temperature of the substrate 2 is maintained at 120 ° C. by the heater 5, the pressure in the processing chamber 1 is maintained at 1 Pa or less by the vacuum pump 13, methane gas at a flow rate of 10 cc / min from the gas inlet 10 and 20 cc / min. An argon gas having a flow rate of a minute is introduced into the processing chamber 1. Next, carbon plasma is formed above the substrate 2 by supplying a high frequency current of 250 kHz to the substrate holder 3 using the high frequency power source 4 at an output of 300 W. Thereby, carbon is ion-implanted on the surface of the base material 2, and the surface of the base material 2 is carburized. Since the 250 kHz high frequency power source 4 exhibits characteristics closer to direct current than the conventionally used high frequency power source having a frequency of 13.56 MHz, the ionized carbon collides with the substrate surface in a high energy state and is further injected. A carburized layer is formed on the substrate surface. In addition, since the oxide film on the surface of the stainless steel substrate is sufficiently removed by powerful ion etching, it is easy to form a high-quality carburized layer on the substrate surface.

  When the above-described carburizing treatment (ion implantation) on the substrate surface was performed for 120 minutes, a carburized layer having a Knoop hardness (load 10 gf) of HK773 was formed on the substrate surface. The result of measuring the carbon distribution on the substrate surface at this time by GDS is shown in FIG.

  FIG. 3 is a diagram showing the relationship between the distance from the substrate surface and the concentration of the contained element. As shown in this figure, although a 0.05 μm carbon-only layer is observed on the base material surface made of austenitic stainless steel, carbon is distributed to around 1.0 μm from that, and the base material surface is carburized. It was confirmed that

(Embodiment 4) Nitriding treatment / DLC film Hereinafter, a surface treatment method for a substrate according to Embodiment 4 of the present invention will be described. In this surface treatment method for a base material, a nitride layer is formed on the surface of the base material by using the plasma processing apparatus shown in FIG. 1, and a DLC film is formed on the nitride layer. The high-frequency power source 4 in this plasma processing apparatus uses a frequency of, for example, 250 kHz, nitrogen gas is used as the processing gas, and hydrocarbon gas is used as the source gas for the DLC film, but toluene gas and acetylene gas are easy to handle. .

  In this embodiment, (1) a nitride layer is formed on the surface of the base material, and a DLC film is formed on the nitride layer; and (2) a DLC film without forming a nitride layer on the surface of the base material. The hardness of the DLC film when the film is formed is compared.

(1) In the case of forming a nitride layer A base material made of austenitic stainless steel SUS304 and a base material made of SKH51 similar to those of the second embodiment are prepared.

  Next, after the oxide layers on the surfaces of the SUS304 base material and the SKH51 base material are removed by etching in the same manner as in Embodiment 2, a nitride layer is formed on the surfaces of the SUS304 base material and the SKH51 base material.

  Thereafter, the temperature of each of the SUS304 base material and the SKH51 base material is maintained at 120 ° C. by the heater 5, the pressure in the processing chamber 1 is maintained at 1 Pa or less by the vacuum pump 13, and the gas introduction port 10 is made of hydrocarbon gas. A source gas such as toluene is introduced into the processing chamber 1 at a flow rate of 5 cc / min. Next, by supplying a high frequency current of 250 kHz to the base material holder 3 using the high frequency power source 4 with an output of 300 W, a thickness of 2. on the nitride layer of each of the SUS304 base material and the SKH51 base material in 30 minutes. A 0 μm DLC film is formed. The film formation rate is about 1.1 nm / second, which is two to three times faster than the conventional DLC film formation method. This is presumably because hydrocarbon decomposition and ionization are promoted by the effect of a 250 kHz high-frequency current having a characteristic close to direct current. Thus, the production cost can be reduced by increasing the film formation rate.

  Subsequently, the Knoop hardness (load 10 gf, load 25 gf) of the DLC film formed on the surface of each of the SUS304 substrate and the SKH51 substrate was measured. The measurement results are shown in FIG.

(2) When a nitride layer is not formed First, a SUS304 base material and a SKH51 base material similar to the base material described above are prepared.

  Next, the oxide layers on the surfaces of the SUS304 base material and the SKH51 base material are removed by etching in the same manner as in the first embodiment.

  Thereafter, a DLC film is formed on the surface of each of the SUS304 base material and the SKH51 base material under the same conditions as those of the DLC film forming method described above.

  Subsequently, the Knoop hardness (load 10 gf, load 25 gf) of the DLC film formed on the surface of each of the SUS304 substrate and the SKH51 substrate was measured. The measurement results are shown in FIG.

  FIG. 4 is a diagram showing the Knoop hardness of the DLC film when the nitriding process is performed and when the nitriding process is not performed in order to investigate the influence of the nitriding process. As shown in this figure, it was confirmed that in both the SUS304 base material and the SKH51 base material, the Knoop hardness of the DLC film formed after the nitriding treatment was increased about twice. In particular, in the case of a SUS304 base material, the hardness of the base material itself before the treatment (load 10 gf) is only about HK 250, so even if a DLC film is formed without nitriding treatment, the hardness (load 10 gf) However, when the SUS304 base material is nitrided, the hardness (load 10 gf) of the DLC film reaches HK2000 or more. In the SUS304 base material having a load of 25 gf, the effect of the present invention is remarkable, and the hardness of the DLC film formed after the nitriding treatment reaches three times or more when not nitriding. Therefore, it has been clarified that the hardness of the DLC film is dramatically improved by forming the DLC film continuously without performing the nitriding process using the high frequency power source having a frequency of 250 kHz without opening to the atmosphere. .

  In the fourth embodiment, a nitride layer is formed on the surface of the base material, and a DLC film is formed on the nitride layer. However, a carburized layer as in the third embodiment is formed on the surface of the base material. However, it is also possible to form a DLC film on this carburized layer.

(Embodiment 5) Carbonitriding / DLC film Hereinafter, a surface treatment method for a substrate according to Embodiment 5 of the present invention will be described. In this substrate surface treatment method, a carbonitriding layer is formed on the surface of the substrate by using the plasma processing apparatus shown in FIG. 1, and a DLC film is formed on the carbonitriding layer. The high frequency power supply 4 in this plasma processing apparatus uses a frequency of, for example, 250 kHz, methane gas and nitrogen gas are used as the processing gas, and the same source gas as that of the fourth embodiment is used as the DLC film source gas.

  In the present embodiment, (1) when only the carbonitriding layer is formed on the surface of the base material, and (2) the carbonitriding layer is formed on the surface of the base material, and the DLC film is formed on the carbonitriding layer. The hardness of the DLC film in the case and (3) the case where the DLC film is formed without forming the carbonitriding layer on the surface of the substrate are compared.

(1) In the case where only the carbonitriding layer is formed on the surface of the base material A base material 2 made of austenitic stainless steel SUS304 similar to that of the first embodiment is prepared, and the base material 2 is prepared in the same manner as in the first embodiment. The oxide layer on the surface is removed by etching.

  Thereafter, the temperature of the substrate 2 is maintained at 120 ° C. by the heater 5, the pressure in the processing chamber 1 is maintained at 1 Pa or less by the vacuum pump 13, and methane gas at a flow rate of 3 cc / min from the gas inlet 10 and 60 cc / min. Nitrogen gas at a flow rate of minutes is introduced into the processing chamber 1. Next, a high frequency current of 250 kHz is supplied to the base material holder 3 by using the high frequency power source 4 at an output of 300 W, thereby forming a plasma composed of carbon and nitrogen above the base material 2. Thereby, carbon and nitrogen are ion-implanted into the surface of the base material 2, and the surface of the base material 2 is carbonitrided. Since the 250 kHz high frequency power source 4 exhibits characteristics closer to direct current than the conventionally used high frequency power source having a frequency of 13.56 MHz, the ionized carbon and nitrogen collide with the surface of the substrate in a high energy state and further injected. Therefore, a carbonitriding layer is formed on the substrate surface.

  Next, the Knoop hardness (load 10 gf, load 25 gf) of the carbonitrided layer formed on the substrate surface was measured. The measurement results are shown in FIG.

(2) When forming a DLC film after forming a carbonitriding layer After forming a carbonitriding layer on the substrate surface as described in (1) above, the carburizing conditions are the same as in the fourth embodiment. A DLC film is formed on the nitride layer with a film formation time of 60 minutes.

  Next, the Knoop hardness (load 10 gf, load 25 gf) of the DLC film formed on the substrate surface was measured. The measurement results are shown in FIG.

(3) When a DLC film is formed without forming a carbonitriding layer First, a base material 2 made of austenitic stainless steel SUS304 similar to that in Embodiment 1 is prepared, and the same method as in Embodiment 1 is used. The oxide layer on the surface of the substrate 2 is removed by etching. Thereafter, a DLC film is formed on the surface of the substrate 2 under the same film formation conditions as in the fourth embodiment.

  Next, the Knoop hardness (load 10 gf, load 25 gf) of the DLC film formed on the substrate surface was measured. The measurement results are shown in FIG.

  FIG. 5 is a diagram showing Knoop hardness when carbonitriding is performed, when carbonitriding is not performed, and when only carbonitriding is performed in order to examine the influence of carbonitriding. As shown in this figure, it was confirmed that even with the carbonitriding process alone, HK1500 was reached in the measurement with a load of 10 gf. Further, it was confirmed that the hardness of the DLC film showed a value close to HK2000 at a load of 10 gf and reached HK1000 or more even at a load of 25 gf even if the carbonitriding treatment was not performed on the base material. Furthermore, it was confirmed that when the DLC film was formed by performing carbonitriding on the base material, the hardness became astonishing about HK3000 at a load of 10 gf and about HK2000 at a load of 25 gf. Therefore, it is clear that the hardness of the DLC film is drastically improved by performing the carbonitriding process using a high frequency power source having a frequency of 250 kHz and continuously forming the DLC film without opening to the atmosphere. It was.

(Sixth Embodiment) Adhesion Strength of DLC Film Prepare a sample in which a DLC film is formed after nitriding the surfaces of SUS304 base material and SKH51 base material by the same method as in (4) of the fourth embodiment. . In addition, a sample is prepared in which a DLC film is formed on the surface of each of the SUS304 base material and the SKH51 base material without nitriding by the same method as in (2) of the fourth embodiment.

  A sample in which a DLC film is formed after carbonitriding is performed on the surfaces of the SUS304 base material and the SKH51 base material by the same method as in (2) of the fifth embodiment is prepared. In addition, a sample is prepared by forming a DLC film on the surface of each of the SUS304 base material and the SKH51 base material without performing carbonitriding by the same method as in (3) of the fifth embodiment.

  The above eight samples, ie, SUS304 base material without nitriding sample 21, SUS304 base material with nitriding treatment sample 22, SKH51 base material without nitriding treatment sample 23, SKH51 base material with nitriding treatment sample 24, SUS304 base Adhesion between the DLC film and the underlayer of Sample 25 without carbonitriding on the material, Sample 26 with carbonitriding on the SUS304 base, Sample 27 without carbonitriding on the SKH51 base, and Sample 28 with carbonitriding on the SKH51 base The strength was measured using a scratch tester, and the measurement results are shown in FIG.

The measurement method using a scratch tester is as follows.
The diamond indenter was pulled at a load rate of 100 N / min while being pressed at 10 mm / min, and the critical load (Lc value) at which the film was broken was determined by AE sensor and microscopic observation.

  FIG. 6 is a diagram showing the results of using a scratch tester to determine the adhesion strength between the DLC film and the base in the presence or absence of the nitriding treatment of the base and the presence or absence of the carbonitriding treatment. As shown in this figure, in the case of the SUS304 base material, the adhesion strength is small, but for both the SUS304 base material and the SKH51 base material, the nitriding treatment is performed as compared with the case where the DLC film is formed on the untreated base material. Alternatively, it was confirmed that the adhesion strength was greater when carbonitriding was performed. Therefore, since the DLC film is continuously formed without releasing the air after performing nitriding or carbonitriding using a high frequency power source with a frequency of 250 kHz, the interface between the DLC film and the base is not soiled. It has been clarified that the adhesion strength between the film and the substrate is dramatically improved.

(Seventh Embodiment) Friction / Wear Characteristics of DLC Film A sample in which a DLC film is formed after nitriding the surface of a SUS304 substrate by the same method as in (1) of the fourth embodiment is prepared. A sample in which a DLC film is formed on the surface of the SUS304 base material without nitriding is prepared by the same method as in (2) of the fourth embodiment.

  A sample in which a DLC film is formed after carbonitriding on the surface of the SUS304 base material by the same method as in (2) of the fifth embodiment is prepared. A sample in which a DLC film is formed on the surface of the SUS304 base material without performing carbonitriding by the same method as in (3) of the fifth embodiment is prepared.

  The above four samples, that is, SUS304 base material without nitriding treatment sample 31, SUS304 base material with nitriding treatment sample 32, SUS304 base material without carbonitriding sample 33, SUS304 base material with carbonitriding treatment sample 34, respectively 7 and 8 show the results of measuring the friction / wear characteristics of the DLC film using a ball-on-disk type friction / wear tester with a measurement load of 5 N, a ball SUJ2, and no lubrication.

FIG. 7 shows the relationship between the friction coefficient and the sliding distance, which is the result of measuring the friction coefficient of the DLC film of each of the non-nitriding sample 31 and the nitriding sample 32 in order to investigate the influence of the nitriding treatment on the friction coefficient. FIG.
FIG. 8 shows the friction coefficient and sliding distance, which are the results of measuring the friction coefficient of the DLC film of the non-carbonitriding sample 33 and the carbonitriding sample 34 in order to investigate the influence of the carbonitriding process on the friction coefficient. It is a figure which shows the relationship.

  As shown in FIGS. 7 and 8, it was confirmed that the DLC film formed on the base material subjected to the nitriding treatment or carbonitriding treatment can reduce the friction coefficient more than the DLC film formed on the untreated base material. It was. It is considered that the DLC film formed on the substrate having high hardness has a smaller friction coefficient because the contact area of the ball is smaller.

(Embodiment 8) Nitriding treatment / silicon-containing DLC film Hereinafter, a surface treatment method for a substrate according to Embodiment 8 of the present invention will be described. In this surface treatment method for a base material, a nitride layer is formed on the surface of the base material by using the plasma processing apparatus shown in FIG. 1, and a silicon-containing DLC film is formed on the nitride layer. The high-frequency power source 4 in this plasma processing apparatus uses, for example, a frequency of 250 kHz, nitrogen gas is used as the processing gas, and silicon compound gas and hydrocarbon-based gas are used as the raw material gas for the silicon-containing DLC film. As the silicon compound gas, it is preferable to use hexamethyldisilazane or hexamethyldisiloxane (hereinafter collectively referred to as HMDS) which can be easily handled and can be formed at a low temperature.

  A base material made of the same austenitic stainless steel SUS304 as in Embodiment 2 is prepared.

  Next, after the oxide layer on the surface of the SUS304 base material is removed by etching in the same manner as in Embodiment 2, a nitride layer is formed on the surface of the SUS304 base material.

Thereafter, the temperature of the SUS304 base material is maintained at 120 ° C. by the heater 5, the pressure in the processing chamber 1 is maintained at 1 Pa or less by the vacuum pump 13, and toluene gas and 2 cc at a flow rate of 5 cc / min from the gas inlet 10. Hexamethyldisilazane (C ₆ H ₁₉ NSi ₂ ) at a flow rate of / min is introduced into the processing chamber 1. Next, by supplying a high frequency current of 250 kHz to the base material holder 3 using the high frequency power source 4 at an output of 300 W, a silicon-containing DLC film having a thickness of 4 μm is formed on the nitride layer of the SUS304 base material in a film formation time of 60 minutes. It is formed. The film formation rate is about 1.1 nm / second, which is two to three times faster than the conventional DLC film formation method. This is presumably because hydrocarbon decomposition and ionization are promoted by the effect of a 250 kHz high-frequency current having a characteristic close to direct current.

In the eighth embodiment, the same effect as in the fourth embodiment can be obtained.
In the present embodiment, since silicon is contained in the DLC film, the friction and wear characteristics can be improved as compared with the DLC film not containing silicon.

  Next, the friction / wear characteristics of the silicon-containing DLC film on the SUS304 substrate produced as described above were measured using a ball-on-disk type friction / wear tester with a measurement load of 5 N and a ball diameter of 6 mm, SUJ2, FIG. 9 shows the results of measurement with a slip rejection reason of 300 m.

  FIG. 9 is a diagram comparing the friction coefficients of the silicon-containing DLC film and the additive-free DLC film in order to investigate the influence of the friction coefficient due to the inclusion of silicon in the DLC film. As shown in FIG. 9, the normal DLC film without addition of silicon has a coefficient of friction of about 0.17, whereas the silicon-containing DLC film has a coefficient of friction reduced to about 0.06. It was confirmed that the frictional characteristics were improved by adding.

  In the eighth embodiment, a nitride layer is formed on the surface of the base material, and a silicon-containing DLC film is formed on the nitride layer. However, the carburized layer as in the third embodiment is formed on the surface of the base material. It is also possible to form a silicon-containing DLC film on the carburized layer, and to form a carbonitriding layer as in the fifth embodiment on the surface of the base material, and to form silicon on the carbonitriding layer. It is also possible to form a containing DLC film. Even in these cases, the friction coefficient of the silicon-containing DLC film can be reduced.

(Ninth Embodiment) Nitriding Treatment / Intermediate Layer / Silicon-Containing DLC Film Hereinafter, a surface treatment method for a substrate according to a ninth embodiment of the present invention will be described. A detailed description of the same parts as those in the eighth embodiment is as follows. Omitted.

  In the ninth embodiment, an intermediate layer for increasing the adhesion strength is formed between the step of forming the nitride layer on the surface of the substrate in the eighth embodiment and the step of forming the silicon-containing DLC film on the nitride layer. Add a process to form. Except this point, the second embodiment is the same as the eighth embodiment.

  Specifically, an intermediate layer including a metal such as a chromium nitride layer (CrN layer) is formed on the nitride layer, and a silicon-containing DLC film is formed on the intermediate layer including the metal. The intermediate layer containing the metal may be other than the chromium nitride layer as long as it has high hardness and excellent adhesion strength. The reason for using such an intermediate layer containing a metal with high hardness is to make the silicon-containing DLC film stronger against shearing force and impact resistance due to external stress.

  In the ninth embodiment, a nitride layer is formed on the surface of the base material, and an intermediate layer is formed on the nitride layer. However, a carburized layer as in the third embodiment is formed on the surface of the base material. It is also possible to form an intermediate layer on this carburized layer, and also to form a carbonitrided layer as in Embodiment 5 on the surface of the substrate, and to form the intermediate layer on this carbonitrided layer. It is also possible.

  In the ninth embodiment, the nitride layer, the carburized layer, or the carbonitrided layer is formed on the surface of the substrate. However, the nitrided layer, the carburized layer, or the carbonitrided layer may not be formed on the surface of the substrate. It is. That is, after removing the oxide layer on the surface of the base material by etching, an intermediate layer can be formed on the surface of the base material, and a silicon-containing DLC film can be formed on the intermediate layer.

(Tenth Embodiment) Silicon Ion Implantation / DLC Film Hereinafter, a surface treatment method for a substrate according to a tenth embodiment of the present invention will be described. In this surface treatment method for a base material, a silicon injection layer is formed by injecting silicon ions into the surface of the base material by using the plasma processing apparatus shown in FIG. 1, and a DLC film is formed on the silicon injection layer. It is. The high frequency power supply 4 in this plasma processing apparatus uses a frequency of, for example, 250 kHz, and HMDS is used as a processing gas.

  A base material 2 made of the same austenitic stainless steel SUS304 as in Embodiment 2 is prepared.

  Next, the oxide layer on the surface of the SUS304 base material is removed by etching in the same manner as in the second embodiment.

  Thereafter, the temperature of the SUS304 substrate is maintained at 120 ° C. by the heater 5, the pressure in the processing chamber 1 is maintained at 1 Pa or less by the vacuum pump 13, and hexamethyldisilazane at a flow rate of 4 cc / min from the gas inlet 10. Is introduced into the processing chamber 1. Next, a plasma containing silicon is formed above the substrate 2 by supplying a high frequency current of 250 kHz to the substrate holder 3 using the high frequency power source 4 at an output of 300 W. Thereby, silicon is ion-implanted into the surface of the base material 2. After injecting silicon for 5 minutes, a DLC film is formed using toluene for 60 minutes in the same manner as in the fourth embodiment. The result of measuring the silicon distribution on the substrate surface at this time by GDS is shown in FIG.

  As shown in FIG. 10, a DLC film is formed on the substrate surface, silicon is distributed in a range of about 0.6 μm from the interface between the DLC film and the substrate, and silicon is injected into the substrate surface. It was confirmed. Although the DLC film is displayed thinner than the actual film thickness, it does not reflect the actual thickness of the DLC film because the carbon was etched early in the GDS measurement.

(Embodiment 11) Removal of DLC film Even when a DLC film is formed by the same method as in Embodiments 4, 5, 8, 9 or 10, the DLC film is again formed after removing the DLC film for some reason. A film may be formed on the material surface. Also in this case, the DLC film can be removed using the plasma processing apparatus shown in FIG.

  Specifically, the temperature of the substrate 2 is maintained at 120 ° C. by the heater 5, the pressure in the processing chamber 1 is maintained at 1 Pa or less by the vacuum pump 13, and oxygen gas is supplied from the gas inlet 10 at a flow rate of 60 cc / min. It is introduced into the processing chamber 1. Next, an oxygen plasma is formed on the DLC film formed on the surface of the base material by supplying a high frequency current of 250 kHz to the base material holder 3 using the high frequency power source 4 at an output of 300 W. Thereby, the DLC film on the substrate surface is ashed by the treatment for 60 minutes, and the DLC film is removed from the substrate surface.

  According to the eleventh embodiment, by using the high frequency power supply 4 with a frequency of 250 kHz, the DLC film can be strongly ashed, and the DLC film can be removed at a high ashing speed.

  As described above in Embodiments 1 to 11, by using the plasma processing apparatus shown in FIG. 1, etching, ion implantation (nitriding, carbonitriding, which cannot be performed without using a plurality of processing apparatuses in the prior art) Etc.), four processes of film formation and ashing can be carried out in one apparatus, and highly reliable DLC films with excellent hardness, adhesion strength, friction and wear characteristics are produced with high efficiency. It becomes possible.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, a base material made of iron is used, but a base material made of another metal (for example, Si, Al, etc.) can also be used.

DESCRIPTION OF SYMBOLS 1 ... Processing chamber 2 ... Base material 3 ... Base material holder 4 ... High frequency power supply (RF power supply)
5 ... Heater 10 ... Gas inlet 13 ... Vacuum pump

Claims (7)

A chamber;
A substrate holder disposed in the chamber and holding the substrate;
A gas introduction path connected to the chamber and introducing an etching process gas into the chamber;
A high frequency power supply for supplying a high frequency output of 50 to 500 kHz in the chamber;
Comprising
A plasma processing apparatus, wherein a plasma of the processing gas for etching is generated in the chamber by a high frequency output supplied from the high frequency power source to remove a surface layer of the substrate. In claim 1,
The gas introduction path is a path for introducing a processing gas for film formation,
After removing the surface layer of the base material, a thin film is formed on the surface of the base material by generating plasma of the processing gas for film formation in the chamber by a high frequency output supplied from the high frequency power source. A plasma processing apparatus. In claim 2,
The gas introduction path is a path for further introducing a processing gas for ashing,
After the thin film is formed, the thin film is removed by generating plasma of the processing gas for ashing in the chamber by a high frequency output supplied from the high frequency power source. In any one of Claims 1 thru | or 3,
The plasma processing apparatus is characterized in that the high-frequency power supply supplies a high-frequency power of 300 kHz or less.   A surface treatment method for a substrate, characterized in that the surface layer of the substrate is removed by generating plasma of a processing gas for etching with a high frequency output of 50 to 500 kHz. In claim 5,
A thin film is formed on the surface of the substrate by removing the surface layer of the substrate and generating plasma of a processing gas for film formation by the high-frequency output. Material surface treatment method. In claim 6,
A method of treating a surface of a substrate, comprising: forming the thin film and then removing the thin film by generating plasma of an ashing processing gas by the high-frequency output.

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