JP3471841B2 - Diamond-like carbon film forming equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond-like carbon thin film forming apparatus. Particularly, the present invention relates to an apparatus capable of efficiently and rapidly forming a diamond-like carbon thin film having various physical properties such as high wear resistance, high smoothness, high insulation, and high hardness while maintaining excellent adhesion to a substrate. It is a thing.

[0002]

2. Description of the Related Art In the PVD field, a sputtering method, an ionization vapor deposition method, etc., and in the CVD field, a plasma CVD method has been studied as a typical forming method using a commercially available apparatus. Particularly in the case of the plasma CVD apparatus, when the capacitively coupled high frequency glow discharge was used, the distance between the electrodes was about 20 to 60 mm, although there was some difference. A schematic of a commercially available high frequency plasma CVD apparatus is shown in FIG.

[0003]

Therefore, in the above-mentioned device, the self-bias required for obtaining the physical properties of the diamond-like carbon thin film required for application is the operating pressure in the low pressure region or the high frequency in the high power region. Due to the limitation of the conditions such as the power supply power, it is difficult to realize the above-mentioned high adhesion to the substrate or high-speed formation.

[0004]

In the physical properties of a diamond-like carbon thin film, the minimum self-bias value that must be imparted during the formation process is the operating pressure, high-frequency power, and electrode of a commercially available device. By investigating from the dependence of the area ratio, etc., we optimized the distance between electrodes with respect to the dimensions of the electrodes that make up the capacitive coupling, and found that there is a universal correlation between the two. Diamond shape of the present invention
The carbon thin film forming apparatus is a parallel plate type high frequency plasma CVD
In the device, is it parallel to the high-frequency power supply electrode on which the substrate is placed?
The distance between the two ground electrodes facing each other in parallel is 9 mm or less.
Capacitive coupling, operating pressure of glow discharge from 50Pa to 10
It is characterized by numerically limiting it to an arbitrary value within the range of 0 Pa.
It Also, between the high frequency power supply electrode and the opposite electrode
For square electrodes, the distance between electrodes is 1/30 of the diagonal dimension or
Is a numerical value for the electrode distance of 1/20 of the diameter for circular electrodes
It is characterized by being limited. In addition, it is put into film formation
The high frequency power supply is 2 as the power density per unit area.
Numerical limitation from W / cm ² at any value within the range of 3W / cm ²
It is characterized by having done. In addition, the carbon source gas for forming the film
Hydrogen gas taken into the film by using ethylene gas
Amount of hydrogen gas added for the purpose of dehydrogenation of carbon
Characteristic that the numerical value is limited to 25 mol% or less with respect to gas
And

[0005]

In the diamond-like carbon thin film forming apparatus of the present invention, the self-bias, which is usually obtained only in the condition range in which a high frequency power is supplied at a low pressure, reduces operating distance and high frequency power by reducing the distance between the electrodes. It can be easily and efficiently obtained by control or mutual control of both. Due to this effect, formation in a high pressure region can be realized, and high-speed formation can be performed with the same self-bias. Further, even in the formation in the low power region, the same self-bias can be obtained, so that it has an effect of promoting damage to the underlying substrate and reduction of residual internal stress of the film itself to promote high quality of the film.

[0006]

EXAMPLE An example of the present invention will be described with reference to FIG.
Using a capacitively coupled parallel plate high frequency plasma CVD apparatus, ethylene gas and hydrogen gas were introduced into the vacuum container 1 from the raw material supply system 6 at a predetermined mixing ratio and flow rate, and the high frequency power supply electrodes were arranged in parallel. 2. A high frequency power of 13.56 MHz is applied between the high frequency power supply system 7 and the counter ground electrode 3 to generate a plasma region 10, and the substrate 4 having a thickness of 0.5 mm and a diameter of 6 inches is generated according to the following reaction conditions. Si
A diamond- like carbon thin film was formed on the wafer. The dimensions of the electrodes were square and both sides were 180 × 180 mm.
In this embodiment, the operating pressure of glow discharge is 50 Pa to 1
As an example of an arbitrary value within the range of 00 Pa, the operating pressure
Forming a diamond-like carbon thin film with a force of 75 Pa
It was At this time, although the reaction time was set to 2 minutes, a diamond-like carbon thin film of about 3.4 μm was formed on the Si wafer. In this diamond-like carbon thin film, no peeling was observed and the film was uniformly formed on the entire surface, and when the Vickers hardness was measured, a very clear indentation was generated, and the hardness was 3900 kg / mm ^{2 according to} the formula. It was
Further, FIG. 3 shows the self-bias characteristics when hydrogen gas was introduced at 200 SCCM and high frequency power was applied at a power density of ² W / cm ² .

[Reaction conditions] Reaction gas: ethylene Purity 99.99% 200
SCCM hydrogen purity 99.999% 50 SCCM RF power: 2.2 W / cm ² operating pressure: 75 Pa distance between electrodes: 8.5 mm Substrate temperature: unheated Reaction time: 2min self-bias: -380V formation rate: 1.7 [mu] m / min In this example, ethylene gas was used as the carbon source gas, but it is needless to say that the same effect can be obtained with other hydrocarbon compounds.

[0008]

[Comparative Example 1] Under the reaction conditions of Example, when the distance between the electrodes was set to 30 mm, the self-bias decreased to -230 V, and the obtained diamond-like carbon thin film had a thickness of about 0.6 μm.
Had a Vickers hardness of 2100 kg /
It was mm ² . The formation rate and hardness were not satisfactory values.

[0009]

[Comparative Example 2] Under the reaction conditions of Example, when the operating pressure was set to 20 Pa, the self-bias became −520 V, the electric field strength in the ion sheath was increased, the etching mode became dominant over the deposition mode, and further damage was caused. It was found that the film thickness and the Vickers hardness could not be evaluated due to the increase of the residual internal stress of the film itself, and that the film thickness deviated from the allowable range of film forming conditions.

[0010]

According to the present invention, the desired self-bias, which is an important factor in the process of forming a diamond-like carbon thin film, can be achieved by setting the distance between the electrodes for realizing capacitive coupling in the high frequency plasma CVD apparatus to 9 mm or less. It has an effect that the operating pressure of the glow discharge can be efficiently and easily obtained even in the high pressure region or the high frequency feeding power in the low power region, and the high speed and high quality diamond-like carbon thin film can be easily obtained. .

[Brief description of drawings]

FIG. 1 Conventionally used high-frequency plasma CVD
Sectional view showing the internal structure of the device

FIG. 2 is a sectional view showing the internal structure of a high-frequency plasma CVD apparatus for forming a diamond-like carbon thin film used in the examples of the present invention.

FIG. 3 is a graph showing the inter-electrode distance and operating pressure dependence of self-bias.

[Explanation of symbols]

1 vacuum container 2 High frequency power supply electrode 3 Opposite ground electrode 4 substrates 5 Pressure measurement system 6 Raw material supply system 7 High frequency power supply system 8 exhaust system 9 Distance between electrodes 10 plasma region 11 Blocking condenser 12 Self-bias monitor terminal

Claims (3)

(57) [Claims] 1. A first electrode connected to a high-frequency supply means, and a second electrode which is arranged at a constant interval from the first electrode and is kept at a ground potential, the first electrode High-frequency power is supplied from the high-frequency supplying means to generate plasma between the first electrode and the second electrode, and a diamond-like carbon film is formed on the substrate arranged on the first electrode. A diamond-like carbon film forming apparatus for forming, wherein the interval is 9 mm or less, and an operating pressure is 50 to 100.
A diamond-like carbon film forming apparatus, which forms a diamond-like carbon film as Pa. 2. A first electrode connected to a high-frequency supply means, and a second electrode which is arranged at a constant interval from the first electrode and which is maintained at a ground potential, the first electrode High-frequency power is supplied from the high-frequency supplying means to generate plasma between the first electrode and the second electrode, and a diamond-like carbon film is formed on the substrate arranged on the first electrode. a diamond-like carbon film forming apparatus for forming, said gap is at 9mm or less, the high frequency power is ^{2W / cm 2 ~3W / cm 2} ,
A diamond-like carbon film forming apparatus, which forms a diamond-like carbon film at an operating pressure of 50 to 100 Pa. 3. The method of claim 1 or 2, wherein the operating pressure is diamond-like carbon film forming apparatus which is a 75 Pa.