JP3424182B2 - Surface treatment 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 surface treatment apparatus and, more particularly, to a surface treatment of a substrate by utilizing plasma generated by discharge of electric power such as direct current, high frequency and microwave. The present invention relates to a surface treatment apparatus used as, for example, a dry etching apparatus or a plasma CVD apparatus.

[0002]

2. Description of the Related Art As an example of a conventional surface treatment apparatus, a surface treatment apparatus used for dry etching, which is one of semiconductor device manufacturing processes, will be described.

Dry etching is used in a wiring pattern forming process which is indispensable for manufacturing semiconductor devices. In dry etching, a mixed gas containing a gas containing halogen as a main component is converted into plasma by discharge, and various active species generated by this (for example, atomic chlorine, atomic fluorine,
Fluorocarbon compounds and their ions, etc.) are reacted with the thin film on the surface of the substrate to remove the thin film portion unnecessary for the structure of the electronic device.

As an example of the surface treatment device used for the above dry etching, an ECR (electron cyclotron resonance) type surface treatment device utilizing the electron cyclotron resonance phenomenon due to the interaction between a microwave and a magnetic field and a Landau damping are utilized. Helicon wave type surface treatment devices and the like are known. The application of these surface treatment devices is currently being studied as a low-pressure high-density plasma surface treatment device.

Here, as an example of the above-mentioned low-pressure high-density plasma surface treatment apparatus, a typical configuration example of a conventional helicon wave type surface treatment apparatus used as a dry etching apparatus will be described with reference to FIG.

In FIG. 6, 11 is a vacuum container for processing a substrate, 12 is a vacuum container for discharge formed by using a dielectric such as quartz, 13 is an electrode also serving as a substrate holding mechanism, and 14 is a substrate to be processed. is there. The two vacuum vessels 11 and 12 are joined and integrated via a vacuum sealing structure. Reference numeral 15 is an exhaust mechanism for bringing the inside of the vacuum containers 11 and 12 into a required reduced pressure state,
Reference numeral 16 is a gas introduction pipe for supplying a discharge reaction gas into the vacuum vessels 11 and 12. Reference numeral 17 is an antenna for supplying high-frequency power for generating discharge in the discharge vacuum container 12 to generate plasma, 18 is a high-frequency power source, and 19 is a matching circuit. Antenna 1 with a specific shape
7 is arranged around the outside of the discharge vacuum container 12 and is supplied with high frequency power from a matching circuit 19. Reference numeral 20 is an electromagnet coil for generating a magnetic field. Further, the electrode 13 is provided with a bias high frequency power source 21, a bias matching circuit 22, and an insulator 23 also serving as a vacuum seal, as a mechanism for supplying high frequency power for substrate bias.

The energy of the ions incident on the substrate 14 can be controlled by the substrate bias generated by the bias high frequency power source 21. Based on this energy control mechanism of incident ions, application to a process such as etching of a silicon oxide film or etching of aluminum which needs to give appropriate energy to ions incident on a substrate in order to promote an etching reaction. You can also

The helicon wave type surface treatment apparatus can obtain a high plasma density at a low gas pressure as compared with the parallel plate type surface treatment apparatus which has been widely used in the past. Utilizing this characteristic, application as a single-wafer dry etching apparatus has been started, which performs etching processing on each substrate precisely and at high speed.

The characteristics of the low-pressure high-density plasma surface treatment apparatus represented by the helicon wave type surface treatment apparatus are as follows.
In addition, it is possible to obtain a sufficient processing speed even at a low discharge pressure. Secondly, since the discharge pressure is low, the electron temperature in the plasma is high. This is the point that the dissociation of the working gas easily proceeds. The second feature is very effective in increasing the processing speed.

[0010]

The most important reason for using dry etching in the fine processing in the semiconductor device manufacturing process is that anisotropic etching, that is, vertical etching of the substrate surface is possible. However, in order to perform vertical etching by dry etching on a fine structure having a size of 1 μm or less, it is required that the ions in the plasma be vertically incident on the substrate to be processed. The simplest method to improve the straightness of ions in plasma is to lower the discharge pressure.

Therefore, it can be said that the low-pressure high-density plasma surface treatment apparatus which can obtain a sufficient treatment rate at a low discharge pressure is most suitable for the dry etching apparatus.

However, in the process of etching a silicon oxide film, for example, it is necessary to selectively deposit a polymerized film of a discharge reaction gas according to the material of the thin film on the substrate. When a low-pressure high-density plasma surface treatment apparatus having the characteristic that the progress of the excessive amount (second characteristic) is used, the deposition amount of the polymer film is reduced, and as a result, the etching rate of the silicon and the silicon oxide film is selected. This raises the problem of the decrease in sex.

Therefore, in order to etch a silicon oxide film using a low pressure high density plasma surface treatment apparatus,
It is necessary to suppress the dissociation of the discharge reaction gas.

Regarding the ECR plasma type surface treatment apparatus,
As a technology to suppress excessive dissociation of discharge gas,
A method of supplying microwave power intermittently is known (Reference 1; Proc. 2nd Int'l. Conf. On Reactive Plasm
as and 11th Symp.on Plasma Processing: Sponsored by Japan Society of Applied Physics (1994) Yokohama, p. 41.). According to this method
The plasma density rises rapidly when the output of the power supply mechanism for plasma generation is supplied, and when the output supply is stopped, it decreases with the time constant determined by the bipolar diffusion of electrons and ions in the plasma. Have.

However, as a phenomenon, etching or C
The time constant of increase and decrease of neutral active species in plasma, which plays an important role in reaction processes such as VD, is generally different from the time constant of increase and decrease of plasma density. The fact that the accuracy of the etching process can be improved by utilizing this phenomenon is described in Reference 1 above.

However, when this method is applied to a process that requires control of ion incident energy by supplying a bias to the substrate, such as the etching of the silicon oxide film, matching of the high frequency bias to the electrode 13 is achieved. It becomes difficult, and there is a drawback that the energy of ion incident on the substrate 14 cannot be controlled. This is because the impedance of the electrode 13 (impedance including plasma) viewed from the output side of the bias matching circuit 22 greatly changes according to the plasma density, whereas the matching circuit generally uses a variable capacitor. This is because it cannot respond to high-speed impedance changes.

In the above device, the bias matching circuit 2
The matching state of No. 2 must be performed with respect to the impedance including the plasma of the electrode 13 during the time when the power is supplied from the power supply mechanism for plasma generation, that is, the time when the plasma is present. However, in an actual matching circuit, when performing automatic matching, for example, the automatic matching circuit adjusts the matching state to a value obtained by averaging the impedance over time, so that the matching state is different from the time when the bias power is supplied. The matching state is achieved, and the efficiency with which the bias power is supplied to the electrode 13 is extremely reduced.

In the case of manual matching, matching can be performed while measuring the voltage of the bias power supplied to the electrode 13 to match the impedance in the presence of plasma. But at this time,
Since it is completely different from the matching state during the time when plasma is not present, abnormal heat generation in the bias matching circuit 22 is caused, and a large amount of reflected waves are generated to destroy the bias high frequency power source 21.

In view of the above problems, an object of the present invention is to realize a plasma generation method by intermittent supply of electric power for discharge and a power bias to a substrate at the same time, and a low-pressure high-density plasma capable of high-speed processing at low pressure. While taking advantage of the features of surface treatment equipment,
An object of the present invention is to provide a surface treatment device applicable to a wider range of processes.

[0020]

A surface treatment apparatus according to the present invention comprises a vacuum container for discharge and substrate processing, an exhaust mechanism for reducing the pressure in the vacuum container, and a discharge gas in the vacuum container. A gas introduction mechanism for introducing, a discharge power supply mechanism for supplying electric power for discharging gas to generate plasma, a substrate holding mechanism (electrode), and a bias power supply for biasing the substrate holding mechanism. a mechanism, a modulation signal generator for generating a modulation signal provided intermittently to output the respective output power of the discharge power supply mechanism and the bias power supply mechanism at the same period, is output from the modulating signal generator
The frequency of the modulated signal that is
Even when the pressure is not supplied, the above plasma does not disappear
High enough to maintain the plasma density and modulated signal
In addition to the bias power that is modulated and supplied by
Even in the case of applying bias power to the substrate holding mechanism,
Configured to let go.

In the above configuration, preferably, the modulation signal generator is single, and the modulation signal output from the modulation signal generator is applied to the discharge power supply mechanism and the bias power supply mechanism. To be done.

In the above arrangement, preferably the modulation signal
The frequency of the signal is characterized by being 100 kHz
It

In the above structure, preferably, each power source of the discharge power supply mechanism and the bias power supply mechanism is a high frequency power source.

[0024]

According to the present invention, the modulation signal generator modulates the discharge power of the discharge power supply mechanism and the bias power of the bias power supply mechanism into intermittent outputs in the same cycle, and the bias applied to the substrate holding mechanism. The electric power for use is converted from the conventional continuous electric power to the intermittent electric power synchronized with the electric power for discharge. In the surface treatment apparatus configured to intermittently supply the electric power for discharge for the purpose of suppressing the excessive dissociation of the discharge gas, the plasma density is temporally changed, so that the plasma is supplied to the substrate holding mechanism. The impedance at the bias power supply point changes over time. Therefore, the optimum matching condition of the bias power supplied to the electrodes also changes with time. Therefore, the bias power is supplied only during the time when the discharge power is supplied. The above-mentioned impedance is almost constant during the supply of the bias power, and the matching state is stable. In a surface treatment system that generates low-pressure and high-density plasma by intermittently supplying electric power for discharge, the method for supplying electric power for bias for controlling the energy of ions entering the substrate has been improved to improve the efficiency of bias. Can be significantly improved. Also output from the modulation signal generator
The output voltage of the discharge power supply mechanism changes the frequency of the modulation signal.
Plasma does not disappear even when it is not supplied
High enough to satisfy the condition that the
When the power is not supplied, the bias power supply mechanism
Even if the output voltage is supplied, a large reflected wave does not occur,
The efficiency of the scan can be improved. So in this case,
In addition to the bias power that is modulated and supplied with the modulation signal,
Bias power is applied to the substrate holding mechanism during that time.
To get it .

Modulation signals output from two synchronized modulation signal generators provided for the discharge power supply mechanism and the bias power supply mechanism, respectively, are supplied to the discharge power supply mechanism and the bias power supply. To the mechanism separately,
By eliminating the rising or falling transient state in the temporal change of the density of the plasma generated by the electric power for discharge, by supplying the electric power for bias during the period when the impedance of the substrate holding mechanism is held in a low constant state,
A very precise match can be made to the plasma-containing impedance of the substrate holding mechanism.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a first embodiment of a surface treatment apparatus according to the present invention. The surface treatment apparatus shown in this embodiment is a helicon wave type surface treatment apparatus as an example of a low pressure high density plasma surface treatment apparatus. In FIG. 1, elements that are substantially the same as the constituent elements of the conventional surface treatment apparatus described with reference to FIG. 6 are given the same reference numerals.

In FIG. 1, a discharge vacuum container 12 formed by using a dielectric material such as quartz on a vacuum container 11 for processing a substrate.
Is placed and fixed. These two vacuum vessels 1
A structure capable of being vacuum-sealed is formed at the boundary between 1 and 12.
The internal spaces of the vacuum chambers 11 and 12 are maintained in a vacuum state (reduced pressure state) necessary for performing the surface treatment of the substrate, and the discharge reaction gas introduced therein is discharged with supply power to generate a required plasma. Is generated. The vacuum container 11 is held at the ground potential.

An electrode 13 also serving as a substrate holding mechanism is installed in the vacuum container 11 with its substrate holding surface facing the discharge vacuum container 12. The electrode 13 is insulated from the vacuum container 11 by a ring-shaped insulator 23. The insulator 23 vacuum-seals the vacuum container 11 and the electrode 13. This electrode 1
Surface treatment is performed on the substrate to be processed 14 placed on the substrate 3.

A ring-shaped electromagnet coil 20 is installed around the outside of the discharge vacuum container 12. Also, the vacuum container 11
An evacuation mechanism 15 is provided in the chamber to evacuate the gas existing in the internal spaces of the vacuum vessels 11 and 12 to form a vacuum state. Further, a predetermined flow rate of plasma generating gas is introduced into the vacuum container 11 by a gas introducing pipe 16 and a gas introducing mechanism (not shown). It is general to adjust the exhaust speed of the exhaust mechanism 15 and the gas introduction flow rate by the gas introduction mechanism by a controller (not shown), and thereby set the pressure of the vacuum vessels 11 and 12 to a predetermined value.

An electric power supply mechanism for supplying electric power necessary for electric discharge is attached to the electric discharge vacuum container 12. The discharging power supply mechanism includes a high frequency power supply 18, a matching circuit 19 and an antenna 17. The antenna 17 is the vacuum container 1
2 is arranged around the outside. The high frequency power generated from the high frequency power supply 18 is matched with a matching circuit 19 for impedance matching.
Is supplied to the antenna 17 via. The structure of the antenna 17 is described in, for example, Document 2: Journal of Vacuum Science.
and Technology, A10 (1992) 1389. As for the discharge power supply mechanism for generating plasma, a microwave power supply mechanism may be used instead of the high frequency power supply mechanism.

A bias power supply mechanism is attached to the electrode 13 also serving as a substrate holding mechanism, and the necessary bias power is supplied to the electrode 13. The bias power supply mechanism includes a high frequency bias power supply 21 for bias and a matching circuit 22. The high frequency power generated from the high frequency power supply 21 is supplied to the electrode 13 via the matching circuit 22. Regarding the bias power supply mechanism, a DC or microwave power supply mechanism may be used instead of the high frequency power supply mechanism.

Both the discharging high frequency power source 18 and the bias high frequency power source 21 have a built-in circuit structure whose output can be modulated by a modulation signal given from the outside. In this embodiment, the discharging high frequency power supply 18 and the bias high frequency power supply 21 input the rectangular wave output from the rectangular wave generator 24 as a modulation signal, perform modulation based on this square wave, and intermittently output. Occurring in a sudden way. The modulation signal is not limited to the rectangular wave.

With reference to FIGS. 1 and 2, the basic operation of the surface treatment apparatus having the above configuration will be described. FIG. 2 shows a timing chart of various waveforms, (a)
Is the output voltage waveform of the rectangular wave generator 24, (b) is the output voltage waveform of the discharge power supply mechanism, (c) is the change in plasma density, and (d) is the electrode 13 as seen from the output side of the bias matching circuit 22. Change in impedance, including plasma
(E) schematically shows the output voltage waveform of the bias power supply mechanism. In FIG. 2, for example, the frequency of the power supply mechanism for discharge is 13.56 MHz, the frequency of the power supply mechanism for bias is 40 kHz, the pulse width of the rectangular wave is 0.4 msec, and the cycle is 1 msec.
The duty is set to 40%.

First, the inside of the processing vacuum vessel 11 and the discharge vacuum vessel 12 is evacuated by the evacuation mechanism 15 to bring it to a required reduced pressure state. After that, a predetermined gas is introduced into the vacuum containers 11 and 12 by the gas introduction pipe 16 and the gas introduction mechanism so as to have a predetermined pressure. This predetermined pressure is determined by the target surface treatment process.

Next, when the intermittent high-frequency power generated by the high-frequency power source 18 for discharge is supplied to the antenna 12 through the matching circuit 19, high-frequency discharge is generated in the inner space of the discharge vacuum container 12, and plasma is generated. To be done.
The generation state of plasma at this time is determined depending on the structure of the antenna 17 and the strength of the magnetic field generated by the electromagnet coil 20. Further, the intermittent high frequency power generated by the bias high frequency power supply 21 is supplied to the electrode 13 through the bias matching circuit 22. The ions in the plasma are accelerated by the high frequency power biased on the electrode 13 and enter the surface of the substrate 14. As a result, the surface treatment is performed on the substrate 14.

In the surface treatment apparatus of this embodiment, the output voltage of the rectangular wave generator 24 modulates the outputs of the discharge high frequency power source 18 and the bias high frequency power source 21 so as to be generated intermittently. As shown in FIG. 2, the rectangular wave generator 2
According to the output voltage waveform (rectangular wave) 31 of No. 4, the output voltage waveform 32 of the electric power supply mechanism for discharge is modulated. As a result, as shown in FIG. 2C, the density of plasma generated by the electric power supplied from the antenna 17 of the electric power supply mechanism for discharge temporally changes. The change 33 in the plasma density is
The output voltage of the discharge power supply mechanism starts to rise as indicated by the reference numeral 33a at the same time when it is supplied to the antenna 17, and reaches a steady state 33b after a certain delay time. When the output voltage of the discharge power supply mechanism is no longer supplied to the antenna 17, the plasma density decreases with a certain time constant as indicated by reference numeral 33c, and reaches zero 33d after a certain delay time. FIG. 2 shows an example in which the frequency of the rectangular wave 31 is 1 kHz. The optimum value of the frequency of the rectangular wave 31 differs depending on the time constant of blinking plasma and the time constant of generation and extinction of active species in plasma, but the basic phenomenon is the same regardless of the frequency of the rectangular wave. .

At this time, the impedance 34 including the plasma when the electrode 13 is viewed from the output side of the bias matching circuit 22 greatly changes in accordance with the change 33 in the plasma density, as shown in FIG. 2D. . This is because the impedance when the plasma density is high shows a small value as indicated by reference numeral 34b due to the resistance component of the plasma in contact with the electrode 13 and the capacitance component due to the sheath formed on the surface of the electrode 13, while the impedance is low. The impedance when the density is low or plasma is not present is electrode 1
This is because it is determined only by the stray capacitance of 3 and becomes large as indicated by reference numeral 34a. Since the matching circuit 22 generally uses a variable capacitor as described above, it is not possible to cope with such a high-speed impedance change.

Therefore, by using the rectangular wave generator 24, the high frequency power source 21 of the bias power supply mechanism,
The high frequency power supply 18 of the discharge power supply mechanism is synchronized with the discharge power and the bias power to be supplied intermittently. FIG. 2E shows an output voltage waveform 35 of the bias high frequency power supply 21.

As described above, in the present embodiment, since the output of the bias power supply mechanism is supplied in synchronization with the output of the plasma generation power supply mechanism, that is, in synchronization with the change in the plasma density, the bias power is supplied. The impedance of the electrode 13 including the plasma becomes substantially constant during the time that the current is being supplied. Therefore, the bias matching circuit 22 is
It suffices if the impedance corresponding to the reference numeral 34b in FIG. 2D is matched. This state can be easily achieved by automatic or manual alignment. This eliminates all the problems of the prior art.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a diagram showing the configuration of the surface treatment apparatus according to the second embodiment of the present invention. In FIG.
Elements that are substantially the same as the elements described in the above embodiments are given the same reference numerals.

The characteristic configuration of this embodiment will be described. In the present embodiment, a second rectangular wave generator 25 having the same cycle as the rectangular wave generator 24 and a different duty is provided separately, and the rectangular high frequency power supply 21 is modulated by this rectangular wave generator 25 to intermittently generate electric power. . Square wave generator 24 and square wave generator 25
Are connected via a delay circuit 26. By providing the delay circuit 26, regarding the output relationship of the rectangular wave generation circuits 24 and 25, when one rectangular wave pulse is output from one rectangular wave generator 24, the other rectangular wave generator 25 outputs the rectangular pulse. After the occurrence of the above, a rectangular pulse having different duty is output after a certain delay time (τ). Further, it is preferable that the delay time (τ) is set to be about the time constant of the decay of the plasma density. The configuration and operation of the device in the other parts of this embodiment are the same as in the case of the first embodiment described above.

FIG. 4 is a waveform diagram showing the operation of the surface treatment apparatus of the second embodiment. In FIG. 4, (a) is the output voltage waveform of the rectangular wave generator 24, (b) is the output voltage waveform of the discharge power supply mechanism, (c) is the change in plasma density, and (d).
Is a change in impedance including plasma of the electrode 13 viewed from the output side of the bias matching circuit 22, (e) is an output voltage waveform of the bias power supply mechanism, and (f) is an output voltage waveform of the rectangular wave generator 25. To indicate. The frequency of the discharge power supply mechanism is 13.56 MHz, the frequency of the bias power supply mechanism is 40 kHz, the pulse width of each rectangular wave is 0.4 msec, and the cycle is 1 msec.

When the output voltage 32 of the discharge power supply mechanism for generating the plasma is intermittently supplied, the rising portion 33a or the falling portion in the temporal change of the plasma density (reference numeral 33 in FIG. 4C). The transient state of the portion 33c occurs. These transient states are shown in FIG.
It is also reflected in the impedance of the electrode 13 including the plasma as shown in FIG. Therefore, when the bias matching circuit 22 is used to perform very precise matching with respect to the impedance including the plasma, a rectangular wave input to the bias power supply mechanism is generated in a state where the impedance including the plasma of the electrode 13 is low. The output may be limited to the time T1 which is kept constant. Therefore, a rectangular wave generator 25 that outputs an output waveform 41 delayed by a time τ with respect to the output waveform 31 of the rectangular wave generator 24 is separately provided, and the rectangular wave generator 25 is generated.
The intermittent output 41 is applied to the high frequency bias power source 21 to perform modulation. In this case, the timing at which the voltage of the rectangular wave generated from the second rectangular wave generator 25 becomes 0V is different from the timing at which the output voltage of the rectangular wave generator 24 becomes 0V, so the two rectangular wave generators 24 , 25 have different output waveform duty.

According to the second embodiment described above, the period during which the bias power is applied to the electrode 13 is strictly constant when the impedance of the electrode 13 changes (FIG. 4D) when the impedance including plasma is low. Time held at T
Since it is limited to 1, the transitional state of the rising edge 33a and the falling edge 33b can be eliminated, and extremely precise matching can be performed.

Next, a third embodiment of the present invention will be described with reference to FIG. The structure of the apparatus in this embodiment is based on the structure of the first embodiment. FIG. 5 shows various timing charts similar to FIG. 2 for explaining the characteristic operation of the surface treatment apparatus according to the present embodiment. (A) to (e) of FIG.
Correspond to (a) to (e) of FIG. 2, respectively. However, in the present embodiment, the repetition frequency of the rectangular wave generated by the rectangular wave generator 24 is 100 kHz (the cycle is 10 μsec.
), And increased the repetition rate.

When the repetition rate is increased, FIG.
As shown in (c), the plasma density does not disappear even when the output voltage of the discharge power supply mechanism (shown in FIG. 5B) is not supplied, and the density is maintained above a certain level. It However, since the plasma density to be maintained differs depending on the type of gas, the pressure, etc., FIG. 5C shows an example of the plasma state. In the discharge state shown in this embodiment, as shown in FIG. 5D, the change in the impedance of the electrode 13 including the plasma is smaller than that in the other embodiments. Thus, when the repetition rate of the rectangular wave, which is the modulation signal provided from the rectangular wave generator 24 to the discharging power supply mechanism, is high, the output voltage of the bias power supply mechanism during the time when the discharging power is not supplied. , The bias efficiency can be improved without generating a large reflected wave. Therefore, by utilizing the modulation signal of the rectangular wave generator 24, the bias power synchronized with the discharge power of the discharge power supply mechanism is supplied from the bias power supply mechanism to the electrode 1.
In addition to the above, the required level of bias power is also supplied to the electrode 13 during the modulated bias power.
Can be given to.

The output control for the bias power supply mechanism as shown in each of the above embodiments can be easily realized by using the function generally provided in the rectangular wave generator.

Although the helicon wave type surface treatment apparatus has been described in each of the above-mentioned embodiments, the surface treatment apparatus of the type in which the discharge power for generating the plasma is intermittently supplied and the bias power is supplied to the substrate. If so, it can be applied to a device that adopts another discharge type. Applicable devices include conventionally used ECR type discharge reaction devices, triode type discharge reaction devices, and the like. Further, it can also be applied to a discharge reactor such as an inductively coupled high-density plasma discharge reactor and a helical resonator discharge reactor which have been recently developed.

[0050]

As is apparent from the above description, according to the present invention, the surface treatment apparatus constructed by utilizing the intermittently supplied high frequency waves as the electric power for discharge is conventionally supplied with the continuous wave. The bias power to the electrodes is configured to be intermittently supplied in synchronization with the discharge power by using the modulation signal generator, so that the substrate can be efficiently biased and the helicon wave type It can be applied to a wider range of processes while taking advantage of the characteristics of a plasma surface treatment apparatus such as a surface treatment apparatus capable of high-speed treatment at a low pressure.

Since the modulation signal generator is shared by the discharge power supply mechanism and the bias power supply mechanism, the structure is simple and the above effect can be easily achieved.

A modulation signal generator is prepared for each power supply mechanism, and the modulation signals output from the two synchronized modulation signal generators are separately supplied to the discharge power supply mechanism and the bias power supply mechanism. The bias power is supplied during the period when the impedance of the substrate holding mechanism is kept low and the transient state of rising or falling in the temporal change of the density of the plasma generated by the discharging power is given. Since it is configured as described above, it is possible to achieve extremely precise matching with respect to the impedance including the plasma of the electrode.

When the present invention is applied to a surface treatment apparatus for performing a plasma process which requires control of ion incident energy to a substrate, its effect becomes remarkable. For example, in a dry etching apparatus for a metal film, a silicon oxide film, or the like, it is possible to improve the etching speed and improve the processing accuracy by applying appropriate substrate incident energy to the ions. Further, even in an apparatus for performing planarization film formation by plasma CVD, it is possible to improve the embedding speed while taking advantage of the effect of suppressing generation of fine particles, which is a feature of intermittent discharge.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a surface treatment apparatus according to the present invention.

FIG. 2 is a timing chart showing an output waveform state and a plasma generation state of each part of the apparatus in the first embodiment.

FIG. 3 is a configuration diagram showing a second embodiment of the surface treatment apparatus according to the present invention.

FIG. 4 is a timing chart showing an output waveform state and a plasma generation state of each part of the apparatus in the second embodiment.

FIG. 5 is a timing chart showing the output waveform state and plasma generation state of each part of the apparatus in the third embodiment of the surface treatment apparatus according to the present invention.

FIG. 6 is a configuration diagram showing a conventional helicon wave type surface treatment device.

[Explanation of symbols]

11 Substrate processing vacuum container 12 Vacuum container for discharge 13 electrodes 14 board 15 Exhaust mechanism 16 Gas introduction mechanism 17 antenna 18 High frequency power supply 19 Matching circuit 20 Electromagnetic coil 21 high frequency power supply 22 Matching circuit 24,25 square wave generator 26 Delay circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/205 C23C 16/52 C23F 4/00 H01L 21/3065 H01L 21/31

Claims (4)

(57) [Claims] 1. A vacuum container, an exhaust mechanism for reducing the pressure inside the vacuum container, a gas introducing mechanism for introducing a discharge gas into the vacuum container, and an electric power for discharging the gas to generate plasma. And a power supply mechanism for discharging,
In a surface treatment apparatus comprising a substrate holding mechanism and a bias power supply mechanism for applying a bias to the substrate holding mechanism, the output power of each of the discharge power supply mechanism and the bias power supply mechanism is intermittently provided at the same cycle. to a modulation signal generator for generating a modulation signal to be output is provided, frequency of the modulated signal output from the modulation signal generator
The number of the output voltage of the discharge power supply mechanism is supplied
Even when not in use, the plasma does not disappear and the plasma density is maintained.
High enough to be held and modulated by the modulation signal
In addition to the bias power supplied by
A surface treatment apparatus , wherein a bias power is applied to the substrate holding mechanism . 2. The surface treatment apparatus according to claim 1, wherein
The surface treatment apparatus, wherein the modulation signal generator is single, and the modulation signal output from the modulation signal generator is supplied to the discharge power supply mechanism and the bias power supply mechanism. 3. The surface treatment apparatus according to claim 1, wherein
The surface treatment apparatus, wherein the frequency of the modulation signal is 100 kHz . 4. The surface treatment apparatus according to claim 1, wherein each power source of the discharge power supply mechanism and the bias power supply mechanism is a high frequency power source. Processing equipment.