JP3445657B2 - ECR plasma etching method for diamond thin film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching method applied for etching a diamond thin film in the process of manufacturing a semiconductor diamond electronic device such as a field effect transistor using the diamond thin film, Electron cyclotron resonance (ECR: El caused by an electric field generated by microwaves)
ECR of a diamond thin film in which the reaction gas is turned into plasma using the ectron cyclotron resonance phenomenon, and the ions in the generated plasma are irradiated to the sample substrate placed in the vacuum container to etch the diamond thin film on the sample substrate. The present invention relates to a plasma etching method.

[0002]

2. Description of the Related Art Diamond has a high hardness and is excellent in heat resistance, chemical resistance, radiation resistance and the like, and although it is an electrically excellent insulator, it can be made into a semiconductor. Since its band gap is as large as about 5.4 eV, its application as a high temperature semiconductor is expected. Also,
It is optically transparent over a wide range from ultraviolet to visible and infrared, and its application to optical windows is being studied.

In the first half of the 1980s, a method for relatively easily performing vapor phase synthesis of a diamond thin film having such excellent characteristics by utilizing a plasma reaction was established. Also,
Similar to bulk diamond, it has been reported that a diamond thin film can be made into a semiconductor by doping with an impurity such as boron (B). In consideration of the potential of the diamond thin film as a highly functional material as described above, a carbide tool coated with a diamond thin film, a speaker diaphragm coating, a heat sink for semiconductor devices, electronic devices such as diodes and transistors, etc. Is being developed. Particularly in the field of electronic materials, the diamond thin film etching technique is becoming important as one of the microfabrication element techniques for producing semiconductor diamond electronic devices.

As described above, the ECR plasma etching method uses the electron cyclotron resonance phenomenon caused by the magnetic field and the electric field generated by the microwave to convert the reaction gas into plasma, and the ions in the generated plasma are stored in a vacuum container. The sample substrate thus arranged is irradiated and the sample substrate is etched. As is well known, when gas is introduced in a low gas pressure state, a magnetic field is applied and microwave power is supplied to generate plasma, the electrons in the plasma are wound around the magnetic field lines along the magnetic field lines by the Lorentz force due to the magnetic field. Move circularly to get on. When the magnetic field strength is adjusted so that the frequency of the circular motion and the frequency of the microwave match, the microwave energy is efficiently converted into the electron kinetic energy by resonance absorption. This is electron cyclotron resonance, in which electrons collide with gas molecules and are ionized to generate ions and electrons one after another to increase the plasma density. If the plasma is kept in such a resonance state, the acceleration of electron collision promotes 10 ^−4.
Discharge is possible even at a low pressure of Torr (1 Torr = about 133 Pa). When such a low-pressure plasma is used, the mean free path of ions is lengthened, so that highly anisotropic etching is possible and even a fine pattern of 1 μm or less can be etched. As the microwave, the industrial frequency of 2.45 GHz is often used, so that the ECR is performed in an appropriate area in the vacuum container.
The magnetic field is applied so that the magnetic field 875 Gs satisfying the condition is generated.

Now, the technical document "SAGrot el al, Appl.Ph
ys. Lett., Vol. 61, No. 19 (1992), p. 2326. ”discloses a method for etching a single crystal diamond thin film by ECR plasma etching using a divergent magnetic field as a magnetic field. (Prior art 1).

FIG . 4 is a diagram showing the structure of an ECR plasma etching apparatus used for carrying out the method of the prior art 1. As shown in FIG. 4 , in this ECR plasma etching apparatus, a pair of magnetic coils 52a and 52b are coaxially arranged at a relatively long distance around the outer circumference of a vacuum container 51. Then, in the vacuum container 51, the sample substrate S is arranged at a position outside the magnetic coil 52b on the right side in the figure located on the side opposite to the microwave introduction side (the right side position in the figure), and the sample is introduced from the microwave introduction side. The divergent magnetic field in which the magnetic field strength gradually decreases in the direction of the substrate S causes the ions together with the electrons in the sample substrate S as a plasma flow.
The single crystal diamond thin film on the sample substrate S is etched by the diverging ion flow.

In this Prior Art 1, when oxygen gas is used as the reaction gas, the etching rate is 200 to 170.
Since it varies in the range of 0 Å / min (20 to 170 nm / min), a mixed gas of oxygen gas and argon gas (oxygen gas concentration: 12.9 vol%) is used as a reaction gas, and the reaction gas pressure is 3.1 mTorr, micro. The single crystal diamond thin film is etched at a wave power of 1000 W, resulting in an etching rate of about 86 Å / mi.
The variation of n is about ± 20% or less so that the reproducibility of the etching rate is improved.

[0008] The technical document “SJ Pearlton et al., Electroni
"cs letters 23rd April 1992, Vol.28, No.9, p.822." discloses a method of etching a polycrystalline diamond thin film by ECR plasma etching using only oxygen gas as a reaction gas. (Prior art 2).

In the prior art 2, only oxygen gas is used as a reaction gas, and a DC bias voltage is applied in the range of 0 to -300 V to a substrate holder (sample table) on which a sample substrate is mounted, so that the etching rate can be improved. It has been shown that improvements and their control are possible. Also, by increasing the oxygen gas pressure to 30 mTorr, about 4000 Å
A high etching rate of / min is obtained.

Technical literature “S. Shikata et al., 2nd Interna
tional conference on the Application of diamond fi
"lms and Related Materials, p.377, (1993)" discloses a method of etching a diamond thin film by a reactive ion etching method using a mixed gas of oxygen gas and argon gas as a reaction gas. (Prior art 3).

In this prior art 3, when the oxygen gas concentration of the mixed gas is 5 vol% or more, the surface roughness of the etched surface of the diamond thin film increases, and oxygen that can obtain a smooth etched surface without protrusions is obtained. Gas concentration is 1 vo
Under the condition of 1% or less, the etching rate is 150Å / mi
It is shown that the number becomes n or less.

[0012]

In the above-mentioned prior art 1, when a diamond thin film is ECR plasma etched, a mixed gas of oxygen gas and argon gas (oxygen gas concentration: 12.9 vol%) is used as a reaction gas. In order to improve the reproducibility of the etching rate, this is in the region where the etching rate is as small as about 86 Å / min, and the cooling of the sample substrate is not taken into consideration. Substrate temperature is 250 ° C
Since the etching rate increases to a certain degree, the etching rate varies by about ± 20%, and the reproducibility of the etching rate is not sufficient. According to the device shown in FIG. 4 , since a pair of magnetic coils are arranged at a relatively long distance and a divergent magnetic field is used by the pair of magnetic coils, the spread of the plasma flow due to the divergence of the magnetic field is performed. Not enough,
There is also a problem that the in-plane uniformity of the etching rate on the surface of the sample substrate (uniformity of etching treatment) is poor.

In the prior art 2, the diamond thin film is EC
When performing R plasma etching, the etching rate is
For example, when the bias voltage is changed in the range of about 300V, the bias voltage does not increase linearly with respect to the bias voltage, but it rapidly increases with the increase of the bias voltage in the low bias voltage region up to about negative 100V. However, it was difficult to precisely control the etching rate.

In Prior Art 3, when a diamond thin film is etched by a reactive ion etching method using a mixed gas of oxygen gas and argon gas as a reaction gas, protrusions are generated when the oxygen gas concentration of the mixed gas is 1 vol% or less. A smooth etching surface that does not occur is obtained,
The etching rate at that time is about 150 Å / min or less, and only the etching condition that allows the diamond thin film to be etched smoothly in a part of the low etching rate region without causing protrusion due to surface roughness has been found. Absent.

The etching surface is not smooth due to protrusions
And the performance of the fabricated semiconductor diamond electronic device
There is a problem that is worse.

Therefore, an object of the present invention is to make a reactive gas into plasma by utilizing an electron cyclotron resonance phenomenon caused by a magnetic field and an electric field generated by a microwave, and irradiate the sample substrate with ions in the generated plasma. When a divergent magnetic field is used as the magnetic field applied to the vacuum container when etching the diamond thin film on the sample substrate, the diamond thin film can be etched smoothly without causing protrusions due to surface roughness. Another object of the present invention is to provide an ECR plasma etching method for a diamond thin film, which is capable of performing an etching process having good reproducibility and controllability with respect to the etching rate.

[0017]

[0018]

According to a first aspect of the present invention , an electric field generated by the magnetic field and the microwave is introduced by introducing a reaction gas into a vacuum container to which a magnetic field is applied and introducing a microwave through a microwave introduction window. Using the electron cyclotron resonance (ECR) phenomenon caused by and, the reaction gas is turned into plasma, and the ions in the generated plasma are irradiated to the sample substrate placed in the vacuum container to etch the diamond thin film on the sample substrate. In the ECR plasma etching method of a diamond thin film to be processed, a divergent magnetic field is formed as the magnetic field applied in the vacuum chamber, a DC bias voltage is applied to the sample substrate and the sample substrate is cooled, and oxygen is used as a reaction gas. Gas and argon gas mixed gas whose oxygen gas concentration range is 2 to 20 vol% , The reaction gas pressure 10mTorr or less,
When the diamond thin film is etched at a microwave power areal density of 2.0 W / cm ² or less, or oxygen gas alone or a mixed gas of oxygen gas and argon gas is used as a reaction gas, and the oxygen gas concentration range is Two
Using a mixed gas of more than 0 vol%, the reaction gas pressure is 10 to 50 mTorr, and the microwave power areal density is 5.
The diamond thin film is etched at 0 W / cm ² or less.

The invention of claim 2 is the diamond according to claim 1.
In an ECR plasma etching method for a Mondo thin film,
The substrate bias applied to the sample substrate is within a voltage range.
Is a DC voltage bias of -10 to -500V, and
When the sample substrate is cooled, the substrate
Characterized in that the temperature is kept below 100 ° C
Is.

[0020]

In the ECR plasma etching method for a diamond thin film according to the present invention, since the diamond thin film is hardly etched with only argon gas as the reaction gas, a mixed gas of oxygen gas and argon gas or an oxygen gas alone is used. There is. The etching rate is
Generally, it increases in proportion to the oxygen gas concentration value. Now,
When ECR plasma etching is performed using only oxygen gas as the reaction gas, the plasma becomes unstable in the low gas pressure region, and when the reaction gas pressure falls below 10 mTorr, the etched surface of the diamond thin film has a serrated surface. And a protrusion was formed.

Therefore, an experiment was carried out at a reaction gas pressure of 10 mTorr or less, using a mixed gas of oxygen gas and argon gas as the reaction gas, and changing the oxygen gas concentration and the microwave power areal density of the mixed gas. as a result,
As the reaction gas, a mixed gas of oxygen gas and argon gas having an oxygen gas concentration range of 2 to 20 vol% is used, the reaction gas pressure is set to 10 mTorr or less, and the microwave power areal density is 2.0 W / cm ^2. By the following, the diamond thin film could be etched smoothly without any protrusion on the etched surface.
The microwave power areal density represents a value obtained by dividing the microwave power value input from the microwave introduction window by the microwave introduction window area.

In the above case, the reaction gas pressure is 10 mTorr.
Below r, the microwave power areal density, which is the energy of plasma, is 2.0 W / cm ² when the value exceeds 2.0 W / cm ² , since protrusions are generated on the etched surface of the diamond thin film due to ion damage. It must be below cm ² . And, the reaction gas pressure is 10 mTo
rr or less and microwave power areal density of 2.0 W /
If the oxygen gas concentration range of the mixed gas as a reaction gas is lower than 2 vol% in cm ² or less, the diamond thin film and the mask material will be significantly damaged and the selectivity will be deteriorated, and a protrusion will be formed on the etching surface. Therefore, the lower limit of the oxygen gas concentration needs to be 2 vol%. Further, when the oxygen gas concentration range of the mixed gas which is the reaction gas exceeds 20 vol%, the function of smoothing the diamond thin film surface by argon ions is lowered and projections are generated on the etching surface, so the upper limit of the oxygen gas concentration is It must be 20 vol%. When the reaction gas pressure is 10 mTorr or less, the mean free path of ions becomes longer than the ion sheath width, so that the ion incident angle can be made perpendicular to the sample substrate surface, and vertical etching becomes easier. There are advantages.

Next, the plasma energy is increased to increase the microphone.
B wave power areal density 5.0 W / cm ²In the following,
As a reactive gas, a mixed gas of oxygen gas and argon gas,
And oxygen gas alone, the oxygen gas concentration of the mixed gas
And the reaction gas pressure was changed. As a result,
Oxygen gas alone, or oxygen gas and Argo
Oxygen gas concentration range is 20 vo with mixed gas
Using a mixed gas of more than 1%, the reaction gas pressure is 10 to
50mTorr, microwave power areal density 5.0
W / cm²By setting the following, the oxygen gas concentration
In the case of etching conditions in which the degree range is 2 to 20 vol%
In the condition range where a higher etching rate can be obtained, the diamond
Mondo thin film without etching protrusion on its etched surface
It could be etched smoothly.

In this case, the microwave power area density is 5.
Below 0 W / cm ² , the reaction gas pressure range is 1
It should be 0 to 50 mTorr. This is because if the pressure is lower than this range, protrusions are formed on the etched surface of the diamond thin film due to ion damage, and if the upper limit reaction gas pressure (50 mTorr) is exceeded, plasma cannot be generated. When the microwave power areal density is 5.0 W / cm ² or less, and the reaction gas pressure is 10 to 50 mTorr, the oxygen gas concentration range of the reaction gas is 20 vol% or less, and ions due to argon ions are used. Since protrusions occur on the etched surface of the diamond thin film due to damage,
It is necessary to exceed 20 vol%. When the microwave power areal density was increased to more than 5.0 W / cm ² , protrusions were formed on the etched surface of the diamond thin film.

In the ECR plasma etching method for a diamond thin film according to the present invention, in addition to the above etching conditions, a bias voltage is applied to the sample substrate and the sample substrate is cooled. By applying a bias voltage to the sample substrate, it is possible to control the ion incident energy to the sample substrate and control the etching rate independently of the plasma density. Can be increased. When the bias voltage is applied to the sample substrate, the bias voltage can be stably applied to the sample substrate even in plasma, and the etching rate can be linearly increased or decreased in proportion to the bias voltage. Good.

Therefore, in the case of DC voltage bias, it is desirable to set the value in the range of -10 to -500V. When the DC bias voltage is smaller than the lower limit value (-10 V) , it is difficult to stably apply the bias voltage to the sample substrate even in plasma, and it is difficult to increase or decrease the etching rate linearly with respect to the bias voltage. Controllability is reduced, while DC bias voltage
This is because when the value is larger than the upper limit value (−500 V) , damage to the diamond thin film becomes large.

Since the etching rate also changes depending on the substrate temperature, it is desirable to prevent the substrate temperature from rising due to the influence of plasma so as to prevent the reproducibility of the etching rate from decreasing. Therefore, the substrate temperature is reduced to 100 by cooling.
It is better to keep the temperature below ℃.

[0028]

From the above, according to the ECR plasma etching method of the present invention using a divergent magnetic field as the magnetic field, the diamond thin film can be similarly etched smoothly without any protrusion on its etching surface. In addition, it is possible to perform an etching process with good reproducibility and controllability with respect to the etching rate. The pair of magnetic coils are preferably arranged closer to each other, so that the plasma spreads well on the surface of the sample substrate and the plasma density is made uniform. It is possible to etch a diamond thin film having excellent internal uniformity.

[0030]

EXAMPLES Examples of the present invention will be described below. First, the ECR plasma etching apparatus will be described.
FIG. 1 is a divergent magnetic field type ECR plasma etching apparatus used for carrying out the ECR plasma etching method according to the present invention.
It is a figure which shows the structure of a table .

In FIG . 1, reference numeral 1 denotes a vacuum container, which is provided with a microwave introduction window 1a made of a quartz glass plate on the upper part thereof and not shown for introducing a reaction gas to be turned into plasma into the inside. A reaction gas supply pipe is provided, and an exhaust port 1b connected to a vacuuming device (not shown) is opened at the bottom. In order to introduce the microwave of frequency 2.45 GHz from the magnetron 2 into the vacuum container 1, at a portion of the microwave introduction window 1a of the vacuum container 1 which is evacuated from the exhaust port 1b and is maintained at a predetermined vacuum degree. The waveguide 3 is connected.

Then, as shown in FIG. 1, in this embodiment,
Is a pair of magnetic coils with the microwave introduction window 1a in between.
The coils 14a and 14b are arranged close to each other, and the magnetic coil
A divergent magnetic field is applied to the vacuum chamber 1 by the tools 14a and 14b.
I am trying to do it. The magnetic field strength that satisfies the ECR condition is 8
It is 75 Gs.

A sample table (sample substrate supporting table) 5 which is movable in the vertical direction in the drawing is arranged in the vacuum container 1, and a sample substrate S is mounted on the sample table 5 by an electrostatic chuck (not shown). Is detachably mounted. The sample table 5 is up and down
The movement can be adjusted in any direction. And the sample table 5
Is provided with a water cooling pipe line (not shown) therein, and is cooled with cooling water in order to keep the sample substrate S at a predetermined temperature or lower.

The sample table 5 is connected to the RF via a capacitor 6.
High-frequency power is supplied from the oscillator 7, whereby a high-frequency substrate bias can be applied to the sample substrate S. The output of the RF oscillator 7 is 10 to 500.
W, the frequency is 100 to 700 kHz. Further, a voltage from the negative DC bias power source 8 is applied to the sample table 5, whereby the sample substrate S is -10 to -500.
A DC bias voltage can be applied within the voltage range of V. The high frequency bias and the direct current bias can be selected by switching the switches 9a and 9b.

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

Example 1

Using the divergent magnetic field type ECR plasma etching apparatus shown in FIG . 1 , the ECR plasma using the divergent magnetic field is generated to etch the diamond thin film, and the surface shape of the etched surface is observed and the etching rate is measured. did. In this case, the hot filament C on the substrate
Polycrystalline diamond thin film is formed by VD method,
The pattern of SiO ₂ thin film is used as a mask on the diamond thin film.
The processed substrate is used as the sample substrate S, and the etching depth
Then, the etching rate was obtained. In the etching , including the comparative example, as shown in Table 1 , a mixed gas of oxygen gas and argon gas and a simple substance of oxygen gas were used as a reaction gas, and the oxygen gas concentration and the microwave power areal density of the mixed gas were used. And were changed as parameters. The reaction gas pressure was 1 mTorr, the DC bias voltage to the sample substrate was -300 V, and the sample table 5 was cooled with cooling water. The results are shown in Table 1 . The examples surrounded by thick lines in Table 1 are examples of the present invention.

[0046]

[Table 1]

As shown in Table 1 , a mixed gas of oxygen gas and argon gas having a concentration range of 2 to 20 vol% was used as the reaction gas, the reaction gas pressure was 10 mTorr or less, and the microwave power was set. When the surface density was 2.0 W / cm ² or less, the diamond thin film could be etched smoothly without any protrusion on the etched surface. The reaction gas pressure is 10 mTorr
When it exceeded, protrusions were formed on the etched surface.

Example 2

The divergent magnetic field type ECR plasma etching apparatus shown in FIG . 1 was used to generate ECR plasma using a divergent magnetic field to etch the diamond thin film, observe the surface shape of the etched surface, and measure the etching rate. did. The etching is shown in the table, including the comparative example.
As shown in FIG. 2 , a mixed gas of oxygen gas and argon gas and a simple substance of oxygen gas were used as the reaction gas, and the oxygen gas concentration of the mixed gas and the reaction gas pressure were changed as parameters. The microwave power areal density is 3.3 W / cm ² (microwave power: 1000 W),
The DC bias voltage to the sample substrate was set to -300V, and the sample table 5 was cooled by cooling water. The results are shown in Table 2 . The examples surrounded by thick lines in Table 2 are examples of the present invention.

[0050]

[Table 2]

As shown in Table 2 , as the reaction gas, an oxygen gas alone or a mixed gas of oxygen gas and argon gas having an oxygen gas concentration range of more than 20 vol% is used, and the reaction gas pressure is 10 to 10. At 50 mTorr and a microwave power surface density of 5.0 W / cm ² (microwave power: 1500 W) or less, the etching rate is shown in Table 2.
It was possible to smoothly etch the diamond thin film in a larger area than that in the example of the present invention without the projections on the etched surface. When the microwave power surface density exceeded 5.0 W / cm ² , protrusions were formed on the etched surface.

Example 3

Using the divergent magnetic field type ECR plasma etching apparatus shown in FIG . 1 , ECR plasma was generated using the divergent magnetic field to etch the diamond thin film, and the in-plane uniformity of the etching rate was investigated. In order to examine the in-plane uniformity of the etching rate, in this example, the sample was placed at the center position of the substrate support surface of the sample table and at positions of 1 cm intervals up to 5 cm away from the center position in the peripheral direction (radial direction). Then, a diamond thin film sample substrate having a size of 1 cm × 1 cm was set and etched. The reaction gas is oxygen gas, the reaction gas pressure is 10 mTorr, and the microwave power areal density is 3.3 W / cm ² (microwave power: 1
000W), the DC bias voltage to the sample substrate is -150
V, and the sample table 5 was cooled with cooling water. For comparison, the diamond thin film was etched by ECR plasma using a mirror magnetic field under the same etching condition, and the in-plane uniformity of the etching rate was investigated. The results are shown in Figure 2 .

When the diamond thin film was etched by ECR plasma using a divergent magnetic field, the variation in etching rate between the central position and the position 5 cm away from the central position was within about 2%. On the other hand, when the mirror magnetic field was used, the variation in etching rate was about 5%. As described above, by using the divergent magnetic field, it is possible to etch the diamond thin film having excellent in-plane uniformity of the etching rate. It was confirmed that the etching rate was lower when the divergent magnetic field was used than that when the mirror magnetic field was used because the plasma density was lowered.

Example 4

The divergent magnetic field type ECR plasma etching apparatus shown in FIG . 1 was used to generate ECR plasma using a divergent magnetic field, and the DC bias voltage applied to the sample substrate was changed in the range of zero to about -350 V to produce diamond. The thin film was etched and the controllability of the etching rate by the substrate bias was investigated. The reaction gas was oxygen gas, the reaction gas pressure was 10 mTorr, the microwave power area density was 2.3 W / cm ² (microwave power: 700 W), and the sample table 5 was cooled with cooling water. Figure the result
3 shows. As shown in FIG. 3 , the etching rate could be linearly increased or decreased in proportion to the bias voltage. At this time, the variation in etching rate was within 5%.

[0057]

[0058]

ECR of diamond thin film according to the present invention, according to the present invention
According to the plasma etching method, the diamond thin film can be subjected to a smooth etching process without producing projections that cause the etching surface to have a jagged sawtooth shape and deteriorate the performance of, for example, a semiconductor diamond electronic device. With respect to the above, it is possible to perform an etching process with good reproducibility and controllability, and since ECR plasma using a divergent magnetic field is used,
It is possible to etch a diamond thin film having excellent in-plane uniformity of etching rate.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a divergent magnetic field type ECR plasma etching apparatus used for carrying out an ECR plasma etching method according to the present invention.

FIG. 2 is a view according to the present invention, showing the center of a sample substrate.
It is a graph which shows the relationship between a position and an etching rate.

FIG. 3 is a diagram according to the present invention, which is applied to a sample substrate.
A graph showing the relationship between the DC bias voltage and the etching rate.
It is.

FIG. 4 is an ECR program used for performing the method of Prior Art 1;
It is a figure which shows the structure of a plasma etching apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum container 1a ... Microwave introduction window 1b ... Exhaust port 2 ... Magnetron 3 ... Waveguide 5 ... Sample stand 6
... Capacitor 7 ... RF oscillator 8 ... DC bias power supply 9a, 9b ... Switch 14a, 14b ... Magnetic coil S ... Sample substrate

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Kinoshita Takashi Tsukadai 1-5-5 Nishi-ku, Kobe-shi, Hyogo Prefecture Kobe Steel Co., Ltd. Kobe Research Institute of Technology (72) Toshihisa Nozawa Nishi-ku, Kobe-shi, Hyogo 1-5-5 Takatsukadai Kobe Steel Works, Ltd., Kobe Research Institute (56) References JP-A-6-132254 (JP, A) JP-A-5-326415 (JP, A) JP-A-6 -37046 (JP, A) JP-A-6-5548 (JP, A) JP-A-5-67586 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/3065 C23F 4/00 G01R 33/64

Claims (2)

(57) [Claims] 1. An electron cyclotron resonance (ECR) phenomenon caused by the magnetic field and an electric field generated by the microwave is introduced by introducing a reaction gas into a vacuum container to which a magnetic field is applied and introducing a microwave through a microwave introduction window. In the ECR plasma etching method for a diamond thin film, the reaction gas is turned into plasma by utilizing, and the ions in the generated plasma are irradiated to the sample substrate arranged in the vacuum container to etch the diamond thin film on the sample substrate. A divergent magnetic field is formed as the magnetic field applied in the vacuum container.
Then , a DC bias voltage is applied to the sample substrate and the sample substrate is cooled, and a mixed gas of oxygen gas and argon gas is used as a reaction gas, and the oxygen gas concentration range is 2 to 20 vo.
Using a mixed gas of 1%, the reaction gas pressure is 10 mTo
rr or less, microwave power areal density of 2.0 W / cm ²
The diamond thin film is subjected to etching treatment below, or a reaction gas is prepared by using an oxygen gas alone or a mixed gas of oxygen gas and argon gas having an oxygen gas concentration range of more than 20 vol%. An ECR plasma etching method for a diamond thin film, which comprises etching the diamond thin film at a pressure of 10 to 50 mTorr and a microwave power surface density of 5.0 W / cm ² or less. 2. The substrate via applied to the sample substrate.
Is a DC voltage via with a voltage range of -10 to -500V.
And the sample substrate is subjected to the cooling.
That the substrate temperature is kept below 100 ° C.
The ECR plasma etching method of the diamond thin film according to claim 1 .