JPH08330278A - Surface processing method and surface processing device - Google Patents

Abstract

PURPOSE: To realize good reproducibility of selectivity of etching velocity for a long period when a silicon oxide thin film, etc., is etched by using plasma. CONSTITUTION: As for a method for dry etching, etc., for processing a thin film by using plasma produced by mainly using gas containing at least one kind of carbon atom, fluorine atom and hydrogen atom in molecule, plasma production condition is adjusted to make ratio of intensity of light emission from CF2 molecule in plasma and intensity of light emission from F atom constant. A surface processing device is provided with light emission intensity measuring parts 23, 24 which measure each light emission intensity of CF2 molecule and F atom by dispersing light from plasma, an operational part 25 for calculating ratio of each light emission intensity and a control part 25 for controlling one or both of high frequency power and gas flow rate for holding the ratio constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method and a surface treatment apparatus for subjecting a surface of a substrate to a treatment such as dry etching using plasma, and more particularly to a plasma treatment using a gas containing carbon and fluorine. The present invention relates to a method for etching a silicon oxide thin film by gas discharge generated by high frequency power, and a surface treatment apparatus of a type suitable for the etching.

[0002]

2. Description of the Related Art A so-called dry etching process, which is a process of removing a thin film on a surface of a substrate by using plasma, has been widely used in the production of LSI (Large Scale Integrated Circuit), LCD (Liquid Crystal Display) and the like. Dry etching processes often make use of the physical or chemical action of plasma.

Plasma for dry etching is generated by using various reactive gases. In particular, when dry etching of a silicon oxide thin film is performed, plasma generated by high frequency power using chlorofluorocarbon gas is used. Is frequently adopted. Hereinafter, description will be made focusing on an example of a dry etching process for a silicon oxide thin film, which is a typical dry etching process.

Often used as a CFC gas for dry etching of a silicon oxide thin film is C
F ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₈ , CHF ₃ , CH
It is a gas composed of carbon such as ₂ F ₂ and CH ₃ F, fluorine, and hydrogen. Of these, a gas consisting only of carbon and fluorine is used as the main etching gas, and a gas containing hydrogen is added to make the etching rate different from that of the underlying silicon in the silicon oxide thin film etching. There are many. A method of using hydrogen gas as an additive gas is also common. Conventionally, Freon gas containing chlorine has also been frequently used, but as the regulation of Freon gas is tightened, it is becoming less used in general dry etching processes.

In the plasma of CFC gas, a large amount of atomic fluorine generated by the dissociation of CFC gas by electron impact and molecularly dissociated species such as CF, CF ₂ , CF ₃ and highly reactive active species such as ions thereof. Exists in. The silicon oxide thin film on the surface of the substrate reacts with these active species to generate a highly volatile reaction product, thereby advancing the dry etching process.

The etching of the silicon oxide thin film requires bombardment of the surface of the silicon oxide thin film with ions having an energy of about 100 eV or more. In order to give energy to ions, so-called reactive ion etching (RIE) is generally used in which a substrate to be processed is usually placed on a high frequency electrode and ions are accelerated by a self-bias voltage generated on the electrode surface. .

FIG. 5 shows an example of the configuration of a conventional RIE apparatus using a CFC gas plasma. This RIE device is provided with a vacuum container 12 equipped with an exhaust device 11, a discharge gas introduction device (gas introduction device) 13 for introducing a discharge gas into the vacuum container 12, and a predetermined position in the vacuum container 12. The substrate holder (electrode body) 14 and the power supply mechanism 15 for supplying high frequency power to the substrate holder 14 to discharge the discharge gas and generate plasma. Power supply mechanism 1
Reference numeral 5 denotes a high frequency power source 16 for generating a high frequency, a power supply line 17 for guiding the high frequency power generated by the high frequency power source 16 to the substrate holder 14 in the vacuum container 12, a matching unit 18 arranged on the power supply line 17, and the like. Composed of. The substrate 19 is
It is held on the substrate holder 14. Further, the substrate holder 14 is provided with a mechanism for fixing the substrate 19, a mechanism for controlling the temperature of the substrate 19, and the like.

In the above RIE apparatus, for example, Freon gas is introduced as a discharge gas by the gas introduction device 13 into the vacuum container 12 evacuated by the exhaust device 11, and a predetermined high frequency power is supplied to the substrate holder 14 by the power supply mechanism 15. Supply. The introduced CFC gas is discharged by the high frequency electric field supplied to the substrate holder 14,
Generate plasma. Then, the surface of the substrate 19 is subjected to a predetermined etching process by the physical or chemical action of the generated plasma. The high frequency power supplied is often that of a frequency of 13.56 MHz belonging to the HF band.

[0009]

In the above etching process, the size of the substrate tends to increase due to the demand for manufacturing many devices from one substrate. For this reason, the so-called batch type RIE apparatus that processes a plurality of substrates at the same time is no longer used,
The so-called sheet type RIE apparatus that processes sheets one by one has become the mainstream. In the single-wafer type RIE apparatus, it is necessary to perform high-speed etching in order to ensure productivity equal to or higher than that of the batch type apparatus. In the silicon oxide thin film single-mode RIE device, the electrode interval is made smaller than before, and high-frequency power per unit area of the electrode is supplied about 10 times that of the batch type RIE device, and at the same time, the gas pressure is set to about 1 Torr to generate High-speed etching has been put to practical use by utilizing the above-mentioned high-density plasma.

However, as the pattern of the LSI becomes finer and etching of a pattern of about 0.5 μm is required, the verticality of the etching shape is not excellent, and the etching rate varies depending on the size of the LSI pattern. The problems such as the above became clear, and the above-mentioned RIE
It is the limit point of the device.

In order to solve the problems of the conventional RIE apparatus, an etching apparatus has been developed in which the gas pressure is lowered to 10 mTorr or less than that in the conventional case and the gas is made into plasma by using the low pressure high density plasma generating means. Has been done.
In this etching apparatus, by using a method of accelerating ions by applying a high frequency bias to the substrate to be processed,
High-speed etching is realized. As the low-pressure high-density plasma generating means, an ECR (electron cyclotron resonance) plasma source, an ICP (inductively coupled plasma source), a helicon wave plasma source, etc. are often adopted.

However, the etching method using this type of plasma generating means has characteristics different from the conventional RIE etching method. According to the research conducted by the present inventor, in the plasma generated by the low-pressure high-density plasma generation means as described above, the relative amount of fluorine atoms is compared with the plasma in the conventional RIE device due to the progress of the dissociation of CFC gas. Then it turned out to be very large. Such a gas dissociation phenomenon is common to various low-pressure and high-density plasma generation means. When a CFC gas similar to that used in conventional RIE is used, etching between a silicon oxide thin film and underlying silicon is performed. It was difficult to secure the speed selectivity. Therefore, in order to etch a silicon oxide thin film for manufacturing an LSI using a dry etching apparatus using a low-pressure high-density plasma generating means, the amount of hydrogen gas or CFC containing hydrogen atoms added is adjusted, and plasma is further added. It is essential to develop a new etching method that adjusts the high-frequency power for generation to ensure selectivity with the underlying silicon.

However, the above-mentioned selectivity of the etching rate is rarely determined uniquely by adjusting the amount of gas added and the high-frequency power, and it is difficult to control the history of the apparatus, the temperature of the wall of the plasma generating means, and the like. Since it also changes, it was very difficult to maintain good selectivity at all times. Further, when the selectivity changes with time, the shape of the LSI pattern after the dry etching is changed, so that it is difficult to continuously manufacture electronic devices having certain characteristics.

The object of the present invention is to solve the above-mentioned problems, and for example, etching of a silicon oxide thin film for LSI fabrication is performed by using a surface treatment apparatus utilizing a low pressure and high density plasma generating means. It is an object of the present invention to provide a surface treatment method and a surface treatment apparatus capable of performing dry etching or the like with a high reproducibility of etching rate selectivity over a long period of time when performing surface treatment such as.

[0015]

The surface treatment method according to the first aspect of the present invention (claim 1) is produced mainly by using a gas containing at least one kind of carbon atom, fluorine atom and hydrogen atom in the molecule. In the surface treatment method such as dry etching for treating a thin film performed by using the plasma, the plasma generation conditions are set so that the ratio of the emission intensity from the CF ₂ molecule and the emission intensity from the F atom in the plasma becomes constant. This is the method of adjusting.

According to a second aspect of the present invention (claim 2), in the first aspect of the invention, the gas containing at least one of carbon atom, fluorine atom and hydrogen atom is H ₂ or F _2. , CF ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F
₈ , CHF ₃ , CH ₂ F ₂ , CH ₃ F, CH ₄ , C ₂ H
F ₅ , C ₂ H ₂ F ₄ , C ₂ H ₃ F ₃ , C ₂ H ₄ F ₂ , C
Any one gas of ₂ H ₅ F, or a mixed gas prepared by arbitrarily mixing these gases is used.

According to a third aspect of the present invention (claim 3), in the first or second aspect of the invention, the thin film is a material containing silicon and oxygen.

A surface treatment apparatus according to a fourth aspect of the present invention (claim 4) is a vacuum vessel provided with an exhaust system, a discharge gas introduction system for introducing a treatment gas into the vacuum vessel, and a treatment gas discharged. A plasma generation container for generating plasma, a power supply mechanism for supplying high-frequency power into the plasma generation container to discharge the discharge gas to generate plasma, and a predetermined position in the vacuum container A surface treatment apparatus comprising a substrate holder and treating the thin film on the surface of the substrate on the substrate holder by using the generated plasma, by separating the light generated from the plasma into each emission intensity of CF ₂ molecule and F atom. And a calculation unit that calculates the ratio of the measured emission intensities of the CF ₂ molecule and the F atom, and controls either or both of the high-frequency power and the gas flow rate so as to keep the ratio constant. It is configured to have a control unit for controlling.

[0019]

In the surface treatment method according to the present invention, the ratio of the emission intensity from the CF ₂ molecule to the emission intensity from the F atom in plasma has a strong correlation between the etching rate selectivity and the emission. C measured by spectroscopy
The discharge power, the discharge pressure, the mixing ratio of the etching gas, etc. are controlled so that the ratio value of the emission intensity of the F ₂ molecule and the F atom is kept at a desired constant value, whereby the selectivity of the etching rate is always constant Hold.

In the surface treatment apparatus according to the present invention, the light emitted from the plasma is dispersed by the emission intensity measuring unit to generate CF.
_The emission intensity of each of _two molecules and F atoms is measured, and CF ₂
The emission intensity ratio between the molecule and the F atom is calculated, and either or both of the high frequency power and the gas flow rate are controlled by the control unit so that the ratio is kept constant, and thus the above surface treatment method is carried out. .

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In the following description, an etching method for a silicon oxide thin film necessary for manufacturing an LSI is assumed as an example of a surface treatment apparatus, but the application of the present invention is limited to this type of method. Of course not.

1 and 2 are diagrams showing a plasma emission spectrum used for explaining the characteristics of the dry etching method which is one of the surface treatment methods according to the present invention. More specifically, FIGS. 1 and 2 show that a mixed gas of C ₄ F ₈ and hydrogen is introduced as a dry etching gas into a dry etching apparatus that uses, for example, a helicon wave plasma source as a low-pressure high-density plasma generation means. It is an emission spectrum result of the plasma generated in this way.

When etching a silicon oxide thin film with an etching apparatus using a helicon wave plasma source, the selectivity of the etching rate differs depending on the magnitude of the high frequency power supplied to the helicon wave plasma source. It is revealed by the inventor's research. The present inventor has made a high power mode in which a high frequency power supplied to the helicon wave plasma source is relatively large (for example, 2 KW) to generate high density plasma (electron density of 10 ¹² cm ⁻³ or more), and a helicon wave plasma The high frequency power supplied to the source is made relatively small (for example, 500 W) to generate a slightly low density plasma (electron density of about 10 ¹¹ cm ⁻³ ) and the bias power supplied to the substrate is adjusted to lower the plasma density. The dry etching method has been optimized by dividing into two states, a low power mode that suppresses a decrease in etching rate due to the above.

In order to optimize the dry etching method, the present inventor investigated the correlation between the state of active species in the plasma and the etching result by using emission spectroscopy, and conducted the method shown in this example. It was found that the etching method can be optimized by using it. This will be described in detail below.

FIG. 1 shows the results of emission spectroscopy when the high frequency power supplied to the helicon wave plasma source is 2 KW, that is, in the high power mode. On the other hand, FIG. 2 also shows an emission spectrum result in the case of 500 W, that is, in the low power mode. In FIG. 1 and FIG. 2, the spectral characteristic portion of the F atom is magnified 10 times. The mixing ratio and flow rate of the etching gas are the same in both cases of FIG. 1 and FIG. Further, the substrate holder is supplied with high-frequency (for example, a frequency of 400 kHz) bias power. By adjusting the bias power, the etching rate of the silicon oxide thin film is almost the same under any condition. What is characteristic of the difference between the two spectra is that the emission intensity ratios of the CF ₂ molecule and the F atom are greatly different.

The etching results obtained under these two etching conditions are characteristic in that the etching rate of the silicon oxide thin film is almost the same, but that of the underlying silicon (polycrystalline silicon film). The etching rates are greatly different, that is, the etching selectivity is different.

The ratio of the emission intensity of the CF ₂ molecule to the F atom is
It changes depending on the type or mixing ratio of the etching gas, the gas pressure during etching, and the high frequency power.

The inventor of the present invention has made the relationship between the ratio of the emission intensity and the selectivity of the etching rate by the emission spectroscopy by using the etching pressure, the high frequency power supplied to the low pressure high density plasma generation mechanism and the gas mixture ratio as parameters. As a result of measurement, it was found that there is a good relationship between the emission intensity ratio and the etching selectivity.

FIG. 3 shows the relationship between the emission intensity ratio (ratio of emission intensities of CF ₂ and F) and etching rate selectivity (ratio of etching rates of silicon oxide thin film and polycrystalline silicon thin film). According to FIG. 3, it was found that there is a strong correlation between the emission intensity ratio and the etching rate selectivity, and this relationship holds even when the discharge power, the discharge pressure, etc. are changed.

From the above examples, in a method of dry etching a silicon oxide thin film by a dry etching apparatus adopting a low pressure high density plasma generation mechanism such as a helicon wave plasma source, CF ₂ molecules and By measuring the ratio of the emission intensity of F atoms and appropriately controlling the discharge power, the discharge pressure, the mixing ratio of the etching gas, etc., so as to maintain the value at a desired constant value, the selectivity of the etching rate can be improved. It can be seen that it can always be kept constant.

According to the etching method of the above embodiment, dry etching of the silicon oxide thin film can be performed with good reproducibility. The variation in the selectivity of the etching rate, which has been a problem in the conventional etching method, is that the composition of the active species in the plasma varies due to the deposition of deposits on the plasma contact surface of the vacuum chamber for dry etching. As a result, it is considered that the selectivity of the etching rate changes with time. By applying the etching method according to the above embodiment, CF _{2 which} is deeply related to the selectivity of the etching rate among the active species in the plasma.
It is possible to keep the ratio of molecules and F atoms constant, and reproducibility of etching results can be ensured even when dry etching is continuously performed for a long period of time.

The dry etching method according to this embodiment also has the following advantages. In this type of dry etching apparatus, there is a phenomenon that the generation rate of active species in plasma changes immediately after maintenance of the apparatus. For this reason,
The etching characteristics are likely to change until the inner wall of the vacuum container is sufficiently covered with the deposit by performing dry etching to some extent after the maintenance work. Further, even after the inner wall of the vacuum container is sufficiently covered with the deposit, the temperature of the inner wall of the vacuum container changes due to the radiant heat from the plasma, which may impair the reproducibility of the dry etching rate selectivity. Even with respect to such a phenomenon, according to the etching method according to the present embodiment, the reproducibility of dry etching characteristics can be significantly improved as compared with the conventional case.

FIG. 4 shows an embodiment of a dry etching apparatus for carrying out the dry etching method according to the present invention. The basic components of the dry etching apparatus shown in FIG. 4 are the same as those of the dry etching apparatus described in FIG. 4, elements that are substantially the same as the elements shown in FIG. 5 are assigned the same reference numerals. The dry etching apparatus according to the present embodiment is connected to a vacuum container 12 equipped with an exhaust device 11, a discharge gas introduction device (gas introduction device) 13 for introducing a discharge gas into the vacuum container 12, and a vacuum container 12. The low-pressure high-density plasma generation mechanism 20 arranged as a unit and a power supply mechanism 15 that supplies high-frequency power to the low-pressure high-density plasma generation mechanism 20 to discharge the discharge gas and generate plasma. Power supply mechanism 1
Reference numeral 5 denotes a high frequency power source 16 for generating a high frequency, a power supply line 17 for guiding the high frequency power generated by the high frequency power source 16 to the low pressure high density plasma generation mechanism 20, and a power supply line 17
The matching unit 18 and the like arranged above are configured. Further, a substrate holder 14 on which a substrate 19 to be processed is placed is arranged at a predetermined position in the vacuum container 12. Board holder 14
Is provided with a mechanism for fixing the substrate 19, a mechanism for controlling the temperature of the substrate 19, and the like. The substrate 19 has a diameter of 200 m, for example
It is a silicon wafer having a size of about m. Further, high frequency power can be supplied to the substrate holder 14 by a substrate bias power supply mechanism (not shown).

In the dry etching apparatus of FIG. 4, a gas introduction device 13 introduces, for example, chlorofluorocarbon gas as a discharge gas into the vacuum container 12 evacuated by the evacuation device 11, and the power supply mechanism 15 causes a low-pressure high-density plasma. A predetermined high frequency power is supplied to the generation mechanism 20. The introduced CFC gas or the like is discharged by the high-frequency electric field supplied to the low-pressure high-density plasma generation mechanism 20 to generate plasma. Then, the surface of the substrate 19 is subjected to a predetermined etching process by the physical or chemical action of the generated plasma.

Next, the characteristic structure of the dry etching apparatus according to this embodiment will be described in detail.

Gas introducing device 13 for introducing discharge gas
Is a gas introduction device 21 for CFCs that does not contain hydrogen atoms.
And a CFC gas introduction device 22 containing hydrogen gas. The flow rate of each CFC gas can be controlled independently by each gas introduction device 21, 22.
In addition, when it is necessary to mix three or more kinds of gas, the gas introduction device according to the number is installed.

A window 23 for observing the light emission from the internal plasma is installed at a location corresponding to the plasma generation region of the low-pressure high-density plasma generation mechanism 20. When it is difficult to install such a window 23 in the low-pressure high-density plasma generation mechanism 20, the window may be installed on the wall of the vacuum container 12 so that the direction in which plasma can be observed is oriented. In the case where the deposit is remarkably generated on the inner wall of the low-pressure high-density plasma generation mechanism 20 and the surface of the window 23 is easily soiled, the latter configuration is preferable. The window 23 is made of a material such as quartz glass that does not absorb light in the wavelength range of the light to be measured.

The light from the plasma is guided to the spectroscope 24 through the window 23, and the emission intensity of the light of the wavelength to be observed is measured. In this example, the emission of CF ₂ molecules is 2
The light intensity of 704 nm was used as the emission of F atom at 40 nm. It should be noted that the same results can be obtained with light having other wavelengths as long as they correspond to the light emission from the excited state of the CF ₂ molecule and the F atom.

The emission intensity values (obtained as current values) of the respective wavelengths obtained by the spectroscope 24 are taken into the control device 25. That is, the controller 25 analyzes the data given from the spectroscope 24, and analyzes the CF ₂ molecule and the F ₂ molecule.
Calculate the ratio of the emission intensity from the excited state for an atom.
There is a linear correlation between the ratio of the emission intensity and the etching rate selectivity as shown in FIG. 3 described above. Therefore, by controlling the discharge conditions so as to keep the value of the emission intensity ratio of the CF ₂ molecule and the F atom constant, the selectivity of the etching rate can always be kept constant. Therefore, the control device 25 controls one or both of the output of the high frequency power supply 16 and the gas introduction devices 21 and 22 so that the calculated ratio value becomes constant.

As a specific selection example of the discharge gas, CF ₄ is supplied from the gas introducing device 21 and H is supplied from the gas introducing device 22.
_{When 2} is introduced, it is possible to control the gas flow rate of the gas introduction device 22 by utilizing that the ratio of the emission intensity from the excited state of the CF ₂ molecule and the F atom increases as the supply amount of H ₂ increases. The ratio of emission intensity can be kept constant. In a dry etching apparatus, generally, as the number of processed wafers increases, the emission of light from the excited state of CF ₂ molecules tends to increase and the selectivity of the etching rate tends to increase.
Therefore, based on the plasma observation result, the gas introduction device 22
It is controlled so as to reduce the flow rate, CF ₂ molecules and F
It is possible to keep the ratio of the emission intensity from the excited state of the atoms, that is, the selectivity of the etching rate, constant.

The output of the high frequency power source 16 causes CF ₂
When the ratio of the emission intensity from the excited state of the molecule and the F atom is controlled, when the supplied high frequency power is increased, the CF
By utilizing the phenomenon that the ratio of the emission intensity from the excited state of _two molecules and the F atom becomes small, the ratio of the emission intensity, that is, the above selectivity can be kept constant.

The gas introduced from the gas introduction device 21 is CF
Gas of any one of ₄ , C ₂ F ₆ , C ₃ F ₈ , and C ₄ F ₈ or a mixed gas thereof is introduced, and the gas introduced from the gas introduction device 22 is H ₂ , CHF ₃ , CH ₂ F ₂ ,
CH ₃ F, CH ₄ , C ₂ HF ₅ , C ₂ H ₂ F ₄ , C ₂ H
_In the case of introducing any one of ₃ F ₃ , C ₂ H ₄ F ₂ , and C ₂ H ₅ F or a mixed gas thereof, similarly to the above, only the gas flow rate of the gas introducing device 22 is controlled. By doing so, the ratio of the emission intensity can be kept constant.

According to the dry etching apparatus of the present embodiment having the above-mentioned structure, it is possible to carry out dry etching while always keeping the selectivity of the etching rate constant. As already described in the section “Problems to be solved by the invention”, in the conventional dry etching apparatus, it is attempted to secure the reproducibility of the etching result by controlling the temperature of the vacuum chamber and the gas pressure. Has been. However, even if the discharge conditions are the same, the plasma characteristics often change.
According to the present embodiment, the state of plasma is constantly observed and the result is fed back to the discharge condition, so that it is possible to suppress a slight fluctuation that was difficult to control by the conventional method.

As is clear from the above embodiments, it is possible to observe the reproducibility secured by relying on empirical data in the past, which greatly contributes to the improvement of productivity when mass-producing LSI by dry etching. The greatest feature is that it is made possible by automatic control of plasma characteristics based on data.

Although the high density plasma source has been described in the above embodiment, the dry etching method according to the present invention and the apparatus for carrying out this method are not limited to this.
In addition, although an example in which the present invention is applied to dry etching of a silicon oxide thin film is shown, the purpose of the present invention is to use an emission spectroscopy method as described above to compare active species existing in plasma with different effects. The purpose is to generate plasma with a controlled ratio. Therefore, even when applied to a surface treatment method aiming at any surface treatment using plasma, such as dry etching of materials other than a silicon oxide thin film, plasma CVD, plasma polymerization, etc., the same effect as described in the embodiment is obtained. Can be obtained.

[0047]

As is clear from the above description, according to the present invention, for example, in surface treatment of a dry etching method or apparatus for a silicon oxide thin film, emission of CF ₂ molecules and F atoms from plasma by emission spectroscopy. Since the intensity ratio is measured and the discharge conditions are adjusted so that the ratio value is always constant, the instability of surface treatment such as dry etching characteristics can be improved. In particular, the present invention has a remarkable effect when applied to a dry etching apparatus adopting a low-pressure high-density plasma generation mechanism, and a dry etching method and dry etching for the purpose of high-speed single-wafer processing of large silicon wafers. The practicality of the device can be increased.

[Brief description of drawings]

FIG. 1 is a diagram showing an emission spectrum result when a high frequency power supplied to a helicon wave plasma source is set to 2 KW (large power mode).

FIG. 2 is a diagram showing an emission spectrum result when a high frequency power supplied to a helicon wave plasma source is set to 0.5 KW (small power mode).

FIG. 3 is a diagram showing a relationship between a light emission intensity ratio and etching rate selectivity.

FIG. 4 is a configuration diagram showing an embodiment of a surface treatment apparatus according to the present invention.

FIG. 5 is a configuration diagram showing a conventional RIE device.

[Explanation of symbols]

 11 Exhaust Device 12 Vacuum Container 13, 21, 22 Gas Introducing Device 14 Substrate Holder 15 Power Supply Mechanism 16 High Frequency Power Supply 19 Substrate 20 Low Pressure High Density Plasma Generation Mechanism 23 Window 24 Spectroscope 25 Control Device

Claims (4)

[Claims] 1. A surface treatment method for treating a thin film, which is performed by using plasma generated mainly by using a gas containing at least one kind of carbon atom, fluorine atom and hydrogen atom in a molecule, CF _{2 in} plasma A surface treatment method characterized in that plasma generation conditions are adjusted so that the ratio of the emission intensity from molecules to the emission intensity from F atoms is constant. 2. The gas containing at least one of the carbon atom, the fluorine atom and the hydrogen atom, H ₂ ,
_{F 2, CF 4, C 2} F 6, C 3 F 8, C 4 F 8, CHF
₃ , CH ₂ F ₂ , CH ₃ F, CH ₄ , C ₂ HF ₅ , C ₂
One of H ₂ F ₄ , C ₂ H ₃ F ₃ , C ₂ H ₄ F ₂ , and C ₂ H ₅ F gas, or a mixed gas made by mixing these gases is used. Claim 1
The surface treatment method described. 3. The surface treatment method according to claim 1, wherein the thin film is a material containing silicon and oxygen. 4. A vacuum container provided with an exhaust system, a discharge gas introduction system for introducing a processing gas into the vacuum container, a plasma generation container for discharging the processing gas to generate plasma, and the plasma. A high-frequency power is supplied into the generation container to discharge the discharge gas to generate plasma, and a power supply mechanism for generating plasma is provided, and a substrate holder arranged at a predetermined position in the vacuum container is used to utilize the plasma. In a surface treatment apparatus for treating a thin film on the surface of a substrate on the substrate holder, light generated from the plasma is dispersed to generate CF ₂ molecules and F ₂
Means for measuring each emission intensity of the atom and the measured CF ₂
It has a means for calculating a ratio of the emission intensity of the molecule and the emission intensity of the F atom, and a means for controlling either or both of the high frequency power and the gas flow rate so as to keep the ratio constant. Surface treatment equipment.