JP2008027816A - Plasma processing device, and plasma processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing device capable of executing removal and reform of a film, on the side surface of a processing object substrate by obliquely entering ions into the processing object substrate without increasing the size thereof, and to provide a plasma processing method. <P>SOLUTION: This plasma processing device includes an exhaust means for evacuating the atmosphere in a vacuum vessel 107; a mass flow controller 108 for introducing a gas into the vacuum vessel 107; a plasma generation means (a slot antenna 105 and the like) generating plasma in the vacuum vessel; and a substrate support base 111 for mounting the processing object substrate 110 thereon. The substrate support base 111 includes a plurality of high-frequency power sources 202 for applying high-frequency waves; a phase control means 203 for controlling the phases of the high-frequency waves, applied from the high-frequency power sources 202; and a plurality of high-frequency electrodes 201 for respectively applying the plurality of phase-controlled high-frequency waves thereto. The phases of the high-frequency waves, respectively applied to the high-frequency electrodes 201, are shifted between the high-frequency electrodes 201 adjacent to each other, by the phase control means 203. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus and a plasma processing method for performing processing by making ions from plasma incident on a substrate, and more particularly to a plasma processing apparatus and a plasma processing method for causing ions to enter the substrate obliquely. is there.

The plasma process has played a major role in the remarkable development of the semiconductor industry. The application range covers a wide range such as a plasma CVD apparatus, a sputtering apparatus, a plasma etching apparatus, an ashing apparatus, and an ion implantation apparatus.
In other words, it is no exaggeration to say that the semiconductor manufacturing process relies on the plasma process for most of its core processes.
In the conventional plasma processing apparatus, the incident direction of ions with respect to the substrate has been mainly discussed in the etching process. The directionality was “how to make ions incident perpendicular to the substrate”.
In the etching process, with the miniaturization of the processing dimension, the perpendicularity of incident ions is pursued to the limit in order to maintain the perpendicularity of the cross-sectional shape of the etched pattern.

An exception is the type of apparatus that draws ions from an ion source with an electrode and irradiates the substrate, such as an ion implantation apparatus, but other plasma processing apparatuses take the form of placing the substrate in bulk plasma.
At that time, a positively charged region called a “sheath” is always formed on the surface of the substrate, and the potential of the substrate becomes a negative potential of several volts to several tens of volts compared to plasma. Then, positive ions in the plasma are accelerated by the electric field in the sheath and enter the substrate.
Thus, in the substrate placed in the bulk plasma, the direction and energy of incident ions are all determined by the state of the sheath.
On the other hand, in a device that applies high-frequency power to an electrode on which a substrate is placed, a higher sheath voltage (higher voltage is superimposed on the sheath voltage, the voltage changes periodically, and the sheath voltage ( The difference is that several hundred volts can be obtained.

However, even in the case of such a dynamic sheath, there is no change in the mechanism in which positive ions are incident on the substrate after being accelerated by the sheath.
The sheath is formed with a certain thickness on the surface of the substrate inserted into the plasma. Typical sheath thickness is 0.01-10 mm. If the surface of the substrate is flat when viewed on the thickness scale of the sheath, the sheath is formed with a certain thickness parallel to the surface.
Even if the substrate surface has undulations on the order of 1 μm, the sheath is formed in a planar shape. When high-frequency power is applied to the electrodes installed on the substrate, the sheath surface remains flat and vibrates as it becomes thicker or thinner with a high-frequency frequency.
The ions in the plasma are accelerated in the direction perpendicular to the substrate by the electric field applied to the sheath at each time.

On the other hand, when a substrate having a flat surface is inserted into the bulk plasma, its direction is disturbed by several factors, but ions are generally incident on the substrate perpendicularly.
And this perpendicularity is an effect that is always obtained without great effort, and conversely, it is extremely difficult to greatly disturb this perpendicularity.
The following three points are listed as main factors that disturb the verticality of ions.
1. Ion kinetic energy in plasma (component perpendicular to sheath electric field),
2. Collisional scattering of ions in the sheath (against neutral particles),
3. There are three points: orbital bending due to a magnetic field.
The kinetic energy of ions is about 0.1 eV in the non-equilibrium plasma usually used for semiconductor manufacturing, and is about two orders of magnitude lower than the sheath voltage, so the influence on the inclination of the orbit is considered to be very small.

The influence of ion scattering in the sheath can be estimated from a comparison between the thickness of the sheath and the mean free path.
When a value of 1E11 cm ⁻³ is used as a typical plasma density, the pressure at which the mean free path is approximately the Debye length (a fraction of the sheath width) is about 100 Pa.
Since the operating pressure of plasma normally used in etching is 10 Pa or less, collision scattering of ions in the sheath can be ignored.
Trajectory bending due to a magnetic field is a phenomenon observed in a magnetic field (and a large magnetic field) plasma such as ECR. This effect can be ignored for plasmas that do not use a magnetic field.

As described above, the disturbance of perpendicularity of incident ions hardly occurs under normal operating conditions of the low magnetic field / no magnetic field plasma processing apparatus. Therefore, the ions incident on the substrate were unintentionally perpendicular to the substrate.
Due to this perpendicularity, the plasma etching technique can be applied up to a design rule of 100 nm or less without significant technical change of direction.
As described above, the vertical ion incidence on the substrate has greatly contributed from the viewpoint of microfabrication, but on the other hand, it may be difficult to realize due to the verticality.
One example is the removal of the sidewall protective film. The side wall protective film formed on the pattern side wall during dry etching is an indispensable film for protecting the side wall from active species and maintaining the pattern shape vertical.

However, in the resist ashing process after the pattern is once formed, the strong protective film containing SiO ₂ or Al ₂ O ₃ uses high energy ion bombardment or a gas containing hydrogen or fluorine as described in Patent Document 1. It was possible to remove it using the method of addition.
However, there are problems that the silicon substrate and the metal material are unnecessarily etched by active hydrogen atoms and fluorine atoms, and the substrate is damaged by irradiation with high energy ions.
This also causes a problem that the inner wall material of the container due to fluorine or high energy ions is damaged by irradiation with high energy ions in terms of hardware of the apparatus.
The reason why high energy ion irradiation is necessary even when such a problem occurs is due to the perpendicularity of the incident ions to the substrate.

Here, the relationship between the substrate surface and the sidewall protective film and the incident ions will be described with reference to FIG.
The sidewall protective film 110b is a film that adheres to the side surface of the pattern 110a formed on the substrate 110, and thus is formed in a direction perpendicular to the substrate surface 110c.
Further, since the incident direction of the ions 204 is also perpendicular to the substrate surface 110c, at this time, the ions 204 are incident from a direction substantially parallel to the film surface when viewed from the side wall protective film 110b, and the sputter yield thereof. Is infinitely close to zero.
On the other hand, as a method for removing the sidewall protective film 110b other than the plasma process, there is a method using an amine chemical solution. However, the treatment using a chemical solution has a problem that the process cost is high and the environmental load is large.
Another problem is that it is difficult to form or modify the film on the side surface of the pattern.

Currently, various new structure MOSFETs have been developed for high integration, one of which is a vertical MOSFET. In the vertical MOSFET, it is necessary to form a channel and a gate insulating film on the side surface of the pattern.
As the substrate is highly integrated, the gate insulating film is also thinned with miniaturization. Therefore, it is necessary to use a SiON film as the gate insulating film for the purpose of reducing leakage current. In the planar type transistor, the high performance SiON film is formed by plasma nitriding an SiO ₂ film.
However, as described above, in normal plasma, ions enter perpendicularly to the substrate and do not enter the pattern side surface, and therefore nitrogen cannot be introduced into the SiO ₂ film on the pattern side surface.

Japanese Patent No. 3436931 (Patent Document 1) proposes a plasma processing apparatus having a plurality of high-frequency electrodes on a substrate support.
However, in this plasma processing apparatus, the main focus is on adjusting the sheath voltage to make the processing uniform by adjusting the high-frequency power applied to the plurality of electrodes.
However, the sheath cannot be vibrated spatially only by adjusting the high frequency power.

Japanese Patent Application Laid-Open No. 61-191054 (Patent Document 2) proposes an apparatus in which an ion source is installed obliquely with respect to a substrate as an apparatus for making ions incident obliquely with respect to the substrate.
However, an ion source generally requires a large extraction voltage to obtain a large ion current, and the extracted ions have a high energy of several hundred eV.
In order to perform ion irradiation with low energy, it is necessary to decelerate the extracted ions. However, since the ions are dissipated in the process of decelerating to 100 eV or less, the beam current obtained is very small.
Further, a high vacuum is required, the beam diameter is small, and it is difficult to increase the area of the beam irradiation, and the productivity is low for a large apparatus.

In a conventional plasma processing apparatus, ions incident on the substrate through the sheath are incident substantially perpendicular to the substrate surface. Therefore, the ions cannot be irradiated on the pattern side surface, and the film adhering to the pattern side surface is removed. It was difficult to carry out modification.
In the plasma processing apparatus of another example, since the ion source is installed obliquely with respect to the substrate, as described above, when low-energy ion irradiation is performed, the ions are dissipated and the beam current is Is very small and is not suitable for large area processing.
Japanese Patent No. 3436931 JP-A-61-191054

  Therefore, the present invention eliminates or modifies the film adhering to the side surface of the substrate to be processed by making the ions incident obliquely on the substrate to be processed without limiting the beam diameter and increasing the size. It is an object to provide a plasma processing apparatus and a plasma processing method that can be performed.

In order to solve the above problems, a plasma processing apparatus of the present invention comprises a vacuum vessel, an exhaust means for exhausting the atmosphere of the vacuum vessel, a gas introduction means for introducing a gas into the vacuum vessel, and plasma in the vacuum vessel. In a plasma processing apparatus having a plasma generating means for generating and a substrate supporting means on which a substrate to be processed is placed, a high-frequency power source for applying a high frequency, and a phase for controlling the phase of the high-frequency applied from the high-frequency power source The substrate support means has a control means and a plurality of electrodes to which a plurality of high frequencies whose phases are controlled are respectively applied, and the phase of the high frequency applied to the plurality of electrodes by the phase control means Are shifted between adjacent electrodes.
Furthermore, the plasma processing apparatus of the present invention is characterized in that the phase control means includes a plurality of phase control means having a single output, and each of the phase control means is applied by a plurality of the high-frequency power sources.
Furthermore, the plasma processing apparatus of the present invention is characterized in that the phase control means comprises a phase shifter having a plurality of outputs and is applied by a single high-frequency power source.
Furthermore, the plasma processing apparatus of the present invention is characterized in that the pitch of the electrodes is 10 mm or less.
Furthermore, the plasma processing apparatus of the present invention is characterized in that the frequency of the high frequency is 10 MHz or less.
On the other hand, the plasma processing method of the present invention is a plasma processing method in which plasma is generated by plasma generating means in a vacuum vessel and plasma processing is performed on a substrate to be processed supported by the substrate support means in the vacuum vessel. The substrate support means includes a high-frequency output step for outputting, a phase control step for performing phase control for making phases adjacent to each other different from each other, and a plurality of high-frequency signals for which the phases are different from each other after the phase control. And an individual high frequency applying step for individually applying to a plurality of electrodes.
Furthermore, in the plasma processing method of the present invention, in the phase control step, the phase control of the high frequency output from each of a plurality of high frequency power supplies is performed using a plurality of phase control means having a single output. .
Further, in the plasma processing method of the present invention, in the phase control step, phase control of high frequency output from a single high frequency power source is performed using a phase shifter having a plurality of outputs, and the phase shifter performs adjacent control between adjacent phase shifters. It is characterized in that it generates at least two kinds of high frequencies having different phases.
Furthermore, the plasma processing method of the present invention is characterized in that the pitch of each electrode is 10 mm or less.
Furthermore, the plasma processing method of the present invention is characterized in that the frequency of the high frequency is 10 MHz or less.

According to the plasma processing apparatus of the present invention, a plurality of electrodes having the same size as the sheath width are installed on the substrate support, and high-frequency power having a certain phase difference between adjacent electrodes is applied to the electrodes. Supply.
For this reason, it is possible to remove or modify the film adhering to the side surface of the substrate or the side surface of the pattern by making ions incident obliquely on the substrate without limiting the beam diameter and without increasing the size of the apparatus. Thus, higher performance can be realized.
On the other hand, according to the plasma processing method of the present invention, a phase control step for performing phase control for making the phases of adjacent high-frequency waves different from each other, and a plurality of high-frequency waves for which the phases are different from each other after the phase control are set to And an individual high frequency applying step for individually applying to the electrodes.
For this reason, it is possible to remove or modify the film adhering to the side surface of the substrate or the side surface of the pattern by making ions incident obliquely on the substrate without limiting the beam diameter and without increasing the size of the apparatus. Thus, higher performance can be realized.

  Hereinafter, the present invention will be described with reference to the drawings based on the embodiments.

FIG. 1 is an explanatory diagram for explaining an outline and an internal configuration of a plasma processing apparatus according to a first embodiment of the present invention. FIG. 2 is an enlarged view of a main part of the plasma processing apparatus according to the first embodiment of the present invention. It is a principal part expansion explanatory drawing.
As shown in FIG. 1, the plasma processing apparatus of this example includes a high-frequency oscillator 101, a waveguide 102, a matching unit 103, an annular waveguide 104, a slot antenna 105, a quartz dielectric window 106, and a vacuum vessel. 107.
Further, as shown in FIG. 1, the plasma processing apparatus of the present example is a substrate support means for mounting and supporting a mass flow controller 108, a variable conductance valve 109, and a Si substrate 110 as an example of a substrate to be processed. A substrate support 111 is provided.

As shown in FIG. 1, the plasma processing apparatus of this example includes a high-frequency oscillator 101, a waveguide 102, and a matching unit 103 in an annular waveguide 104.
A slot plate having a slot antenna 105 is provided below the annular waveguide 104, and a quartz dielectric window 106 is interposed between the annular waveguide 104 and the vacuum vessel 107.
The high-frequency oscillator 101 radiates high-frequency power, and a vacuum vessel (plasma processing chamber) 107 through a waveguide 102, a matching unit 103, an annular waveguide 104, a slot antenna 105, and a dielectric window 106 that transmits high-frequency power. Plasma is generated by emitting microwaves inside.
The waveguide 102 constitutes a part of a so-called waveguide path of high-frequency power, and guides the high-frequency power from the high-frequency oscillator 101 to the annular waveguide 104 via the matching unit 103.
The matching unit 103 is an impedance matching unit, and the intensity of each of the traveling wave supplied from the microwave generation source (slot antenna 105) to the load and the reflected wave reflected by the load and returning to the microwave generation source. It has a power meter that detects the phase.
The microwave waveguide path may include an isolator that prevents the reflected microwave from returning to the microwave generation source and absorbs the reflected wave.

The matching unit 103 has a function of matching the microwave between the microwave generation source and the load side via a power meter, and is configured by a 4E tuner, an EH tuner, or a stub tuner, although not shown in detail. Yes.
A plurality of slot antennas 105 are provided at positions near the dielectric window 106 of the annular waveguide 104.

On the other hand, the vacuum vessel 107 is made of a metal conductor and includes a pipe connected to a part of its wall portion by a mass flow controller 108 as a gas introduction unit, and a variable conductance valve 109 as a gas exhaust unit.
The mass flow controller 108 supplies a gas for obtaining a specific plasma by being excited by microwaves in the vacuum vessel 107.

The variable conductance valve 109 is a pressure adjusting means for adjusting the pressure in the vacuum vessel 107, and may be understood as constituting a part of a so-called exhaust means.
In addition, it is necessary to employ | adopt simultaneously the structure of a pressure regulation mechanism with an exhaust means not shown, a variable conductance valve, a pressure gauge, a vacuum pump, and a control part for an exhaust means.
In that case, the control unit adjusts the pressure in the vacuum vessel 107 so that the pressure gauge for detecting the pressure in the plasma processing chamber in the vacuum vessel 107 has a specific value while operating the vacuum pump.
In the variable conductance valve, there is a mode in which the pressure is adjusted by controlling a pressure adjusting valve (a gate valve with a pressure adjusting function made by VAT or an exhaust slot valve made by MKS) that is adjusted by the degree of opening of the valve.
Whether or not the conductance adjusting means is used in the vacuum vessel 107 is based on the manufacturing concept of manufacturing the plasma processing apparatus and is an arbitrary matter.

When a vacuum pump is used to evacuate the inside of the vacuum vessel 107, the vacuum pump is connected via the pressure adjustment valve of the variable conductance valve 109. The vacuum pump is used when the inside of the vacuum container 107 is brought into a vacuum or a state close to a vacuum.
On the other hand, the vacuum vessel 107 includes plasma generating means for generating plasma in the vacuum vessel 107.
As shown in FIG. 1, the plasma generating means is composed of a high frequency oscillator 101, a waveguide 102, a matching unit 103, an annular waveguide 104, each slot antenna 105, a dielectric window 106, and a mass flow controller 108. Yes.
Further, as shown in FIG. 1, a substrate support 111 as a substrate support means for placing and supporting a Si substrate 110 as a substrate to be processed is disposed in the vacuum container 107.

On the other hand, as shown in FIGS. 1 and 2, the substrate support 111 according to the first embodiment of the present invention includes a plurality of high-frequency power sources 202 in a lower region near the placement position of the Si substrate 110 as a substrate to be processed. A plurality of phase control means 203 and a plurality of electrodes 201 are provided.
Hereinafter, each of the plurality of electrodes 201 near the placement position of the Si substrate 110 is referred to as a high-frequency electrode 201.
Each one high frequency power source 202, phase control means 203, and high frequency electrode 201 have an electrical connection relationship as one set as shown in FIG.
Each high-frequency power source 202 includes a high-frequency oscillator RF and applies a high-frequency current or a high-frequency voltage to the phase control means 203 having a connection relationship.
As shown in FIG. 2, each phase control means 203 controls the phase of the high frequency power from the high frequency power supply 202 having each connection relationship and applies it to the high frequency electrode 201 having each connection relationship.
Each phase control means 203 shifts the phase of the high-frequency power so that the phases of the high-frequency power are different from each other with respect to the high-frequency electrode 201 having each connection relationship, and applies the high-frequency power. When shifting the phase of the high frequency power, there is a mode in which a delay is applied to the high frequency output.
Note that the pitch of each high-frequency electrode 201 is preferably set to 10 mm or less in order to achieve good plasma processing and the object of the present invention.

In this example, as a specific example, as shown in FIG. 2, each phase control unit 203 controls the phase so that the phase of the high frequency is shifted by 1/4 period adjacent to (adjacent to) each high frequency electrode 201, The high frequency of the phase is applied to the high frequency electrode 201 having each connection relationship.
As shown in FIG. 2, the high-frequency potential Vrf applied to each high-frequency electrode 201 is different in timing for each adjacent high-frequency electrode 201 with the passage of time t. Repeat the potential and reference potential.
The phase control means 203 is composed of an array of a plurality of phase control means 203 having a single output, and each is applied with a high frequency by a high frequency power supply 202 having a connection relationship. This is given to the electrode 201.
The frequency of the high frequency is preferably set to 10 MHz or less in order to achieve good plasma processing and the object of the present invention.

Here, ions in the plasma will be described. The ions in the plasma are accelerated by the difference between the plasma potential and the potential of each of the high-frequency electrodes 201 and enter the Si substrate 110.
Therefore, when a high frequency having a specific phase difference is applied to each high-frequency electrode 201, the difference between the plasma potential and the potential of each high-frequency electrode 201 appears spatially along the surface of the substrate support 111 as a phenomenon called vibration. Therefore, the thickness and shape of the sheath vary variously (see FIG. 3).
As a result, since ions are accelerated perpendicularly to the interface between the plasma and the sheath, there are places where the ions are perpendicularly incident and obliquely incident on the Si substrate 110 as time passes. Ions are incident on the substrate 110 from various directions.
For this reason, it is possible to easily perform the plasma treatment on the side surface of the Si substrate 110 due to the phenomenon, so that the film can be removed or modified on the side surface of the Si substrate 110 as well. .

In the first embodiment of the present invention, it is possible to provide the substrate support 111 with a temperature control unit. A temperature control part is comprised from a heater and has the aspect of controlling to the temperature suitable for a process.
Although not shown in detail, the temperature control unit measures the temperature of the substrate support 111 and controls energization from a power source (not shown) to the heater wire so that the Si substrate 110 reaches a specific temperature based on the measured temperature.
However, whether or not the temperature control unit is used is based on the manufacturing concept of the plasma processing apparatus, and whether or not it is used is arbitrary.

Next, an example of the plasma processing method of Example 1 of this invention is demonstrated.
First, the vacuum vessel 107 is opened to the atmosphere, and a Si substrate (Si wafer) 110 is set on a substrate support 111 set at a specific temperature, and then the inside of the vacuum vessel 107 is set to 0.1 Pa by an unillustrated exhaust means. Exhaust to an extent (exhaust process).
Next, gas is introduced into the evacuated vacuum vessel 107 using the mass flow controller 108, and the variable conductance valve 109 is adjusted while measuring the pressure with a baratron (not shown) to bring the inside of the vacuum vessel 107 to a specific pressure. Set (pressure adjustment step).
Next, a 2.45 GHz microwave is radiated into the vacuum vessel 107 through the quartz dielectric window 106 by the slot antenna 105 opened at the lower part of the annular waveguide, and a sheet is formed on the surface of the dielectric window 106. A surface wave plasma is generated (plasma generation step).
The plasma generated on the surface of the dielectric window 106 is transported to the Si substrate 110 installed on the susceptor by bipolar diffusion.

On the other hand, in the vacuum container 107, high frequency power is individually output from a plurality of high frequency power sources 202 installed on the substrate support 111 (high frequency output step).
Further, phase control is performed by the plurality of phase control means 203 installed on the substrate support base 111 so that the phases of the plurality of high-frequency powers adjacent to each other are different (phase control step).
Furthermore, the respective high frequencies whose phases are different from each other after the phase control by the plurality of phase control means 203 are applied to the plurality of high frequency electrodes 201 installed on the substrate support 111 (individual high frequency application step). .
As a result, since the difference between the plasma potential and the potential of each high-frequency electrode 201 appears spatially along the surface of the substrate support 111, the thickness and shape of the sheath varies in various ways.
For this reason, since ions are accelerated perpendicularly to the interface between the plasma and the changing sheath, the Si substrate 110 has a place where the ions are perpendicularly incident and a place where the ions are obliquely incident. Ions are incident on the surface and each side surface of the substrate 110 from various directions.

FIG. 3 shows an example of a method for applying the output power of the high-frequency power source 202 in the plasma processing apparatus according to the first embodiment of the present invention, and a change in the sheath thickness of the surface of the Si substrate (Si wafer) 110 and the incident direction of ions. .
In the plasma processing apparatus of Example 1 of the present invention, as shown in FIG. 3, high-frequency power having a certain phase difference is applied to the plurality of high-frequency electrodes 201.
In FIG. 3, the plasma potential Vp and the potential Vrf of each high-frequency electrode 201 are shown simultaneously. The ions 204 in the plasma are accelerated by the difference Vp−Vrf between the plasma potential and the high-frequency electrode 201 potential, and enter the Si substrate.
At this time, as shown in FIG. 3, a high frequency having a certain phase difference is applied to the plurality of high frequency electrodes 201. Then, Vp-Vrf spatially vibrates along the surface of the substrate support 111, and the thickness of the sheath fluctuates as shown by the dotted line in FIG.

Since the ions are accelerated perpendicularly to the interface between the plasma and the sheath, at a certain time, there are places where the ions are perpendicularly incident on the Si substrate (Si wafer) 110 and places where they are obliquely incident. Move with time.
As a result, when a certain time is averaged at a certain point on the surface of the Si substrate (Si wafer) 110, ions are incident from various directions.
The above description is made on the assumption that the passage time of the ions 204 in the sheath is sufficiently shorter than the frequency of the high frequency. The frequency at which the above effect is obtained depends on the type of the ion 204, but is preferably approximately 10 MHz or less.

Next, the relationship between the plasma density and the bias voltage condition applied to the high-frequency electrode 201 and the incident angle of ions will be considered.
First, a sheath voltage _V p _-V rf = _{V 0,} between the sheath width _{d s,} it is known that there is a relationship of Equation 1 below.

d _s = 0.585λ _D (2V ₀ / T _e ) ^3/4 Formula 1

Lambda _D In Formula 1 is Debye length, T _e is the electron temperature. On the other hand, FIG. 4 is a graph showing the results of calculating the relationship between the plasma density, sheath voltage, and sheath width based on Equation 1.
In FIG. 4, values obtained in a typical surface wave interference plasma are used as the values of the plasma density and the electron temperature. As shown in FIG. 4, it can be seen that the lower the plasma density and the higher the sheath voltage, the larger the sheath width.
In order to obtain more accurately the spatial behavior of the sheath when a large number of high-frequency electrodes 201 are arranged, it is necessary to perform electromagnetic field simulation. Here, the discussion proceeds based on the following assumptions.
First, the assumption is made that the spatial vibration of the sheath is described by a sine wave.
When considered in one dimension, it can be expressed by the following equation (2).

d _s (x) = d _s0 {sin (2πx / x ₀ ) +1} Equation 2

Here ds0 is 1/2, _{x 0} of the maximum sheath width is the wavelength of the spatial oscillation. This is shown in FIG.
The high-frequency electrode 201 is spatially discretely arranged. However, when a sinusoidal high-frequency wave is applied to the series of high-frequency electrodes 201, the sheath width is assumed to vibrate spatially with a sine wave. Is considered appropriate.
When the pitch of the high-frequency electrode 201 was set to x _e, in order to vibrate the sheath spatially, it is necessary condition for even x ₀ ≧ 2x _e a minimum. Also, the larger the x _0, the spatial vibration of the sheath approaches the sinusoidal approximation.
Moreover, since ions are accelerated perpendicular to the interface between the plasma and the fluctuating sheath, even if a phenomenon of reducing the beam diameter of the plasma applied to the surface including the side surface of the Si substrate 110 occurs, It is a short time.

  Next, the maximum incident angle of ions is obtained based on the above sine wave approximation. The incident angle of ions corresponds to the inclination of the sheath, and is obtained by differentiating Equation 2 by x. The maximum value corresponds to the maximum incident angle of ions, and is given by the following Expression 3.

θ _max = arctan (2π _ds0 / x ₀ ) Equation 3

Here, θ _max is an ion incident angle measured from the normal of the substrate surface. FIG. 6 shows the result of obtaining the maximum incident angle of ions under the condition of x ₀ = 30 mm based on the sheath width obtained in FIG.
Although the maximum incident angle of ions depends on the plasma density and the sheath voltage, ions can be incident on the Si substrate 110 at a high angle of 45 ° or more if conditions are selected.
The angle dependence of the incident ion flux is also an important factor. In a normal sheath, the flux near the zero angle (vertical) is high, but the flux suddenly decreases at the high angle (horizontal) side.
Therefore, it can be said that the incident angle of ions was substantially perpendicular to the substrate surface. On the other hand, the angular dependence of the flux from the spatially vibrating sheath can be calculated as follows.

It is assumed that the ion flux incident on the sheath from the unit area of the plasma / sheath interface is constant. This assumption is equivalent to the fact that the plasma density is spatially constant even when the sheath vibrates.
Considering in one dimension, in a sheath that is spatially oscillating at d _s (x), the sheath length in the width Δx between x and x + Δx is approximated as follows.
When the sheath length is the shortest (slope is zero), the length is Δx, and the value increases as the slope increases positively or negatively. The increase rate of the sheath length with respect to Δx is obtained by the following equation 4.

√ [1 + {(d _s (x + Δx) −d _s (x)) / Δx} ² ]
→ √ [1+ (dd _s (x) / dx) ² ] Equation 4

For comparison, FIG. 7 shows an example of the calculation result of the normalized ion flux in the case of the conventional sheath. As shown in FIG. 7, in the case of a conventional horizontal sheath, since ions are uniformly perpendicularly incident, the ion flux is extremely reduced except at an incident angle of 0 ° (vertical).
On the other hand, FIG. 8 is a graph showing an example of the calculation result of the normalized ion flux in the case of the sine wave sheath of Example 1 of the present invention.
As can be seen from FIG. 8, the ion flux at an oblique incident angle is not attenuated but is slightly larger than that of the normal incidence. This clearly shows that Example 1 of the present invention has the advantage that the efficiency of treatment with obliquely incident ions is very high.
In the case of a sinusoidal sheath, attention should be paid to the fact that the ion energy varies depending on the incident angle of ions. It can be assumed that the ion energy incident on the Si substrate 110 is equal to the sheath voltage at the location x.
This is a correct assumption when the ion incident angle is small. At this time, the relationship between the sheath voltage and the ion incident angle can be obtained from Equations 1 and 2, and the calculation result is as shown in FIG. become.
As shown in FIG. 9, the incident ion energy at the maximum incident angle is about ½ of the maximum energy. At angles other than the maximum incident angle, ions of two types of energy, high energy and low energy, are incident.

On the other hand, in addition to the sheath, there is a specific dielectric plate (not shown) for covering the Si substrate 110 and the metal of the high-frequency electrode 201 so as not to be exposed between the high-frequency electrode 201 and the sheath end.
The thickness of the Si substrate 110 is generally determined to be about 1 mm. Also, the dielectric plate for covering the high frequency electrode 201 so that the metal is not exposed is preferably about 1 mm from the viewpoint of strength and workability.
Three capacitors, a sheath capacitor Cs, a wafer capacitor Cw, and a dielectric capacitor Cd, are connected in series between the high-frequency electrode 201 and the plasma.
The voltage applied to the high-frequency electrode 201 is distributed to each of the three capacitors, and generally the value of the voltage applied to the sheath is lower than the voltage applied to the high-frequency electrode 201. For this reason, it is necessary to quantitatively calculate and estimate this value.

The values required for the calculation are the relative dielectric constant and thickness of each capacitor. The sheath has a relative dielectric constant of 1 and a thickness of ds, the Si substrate 110 has a relative dielectric constant of 11.8 and a thickness of 1 mm, Al ₂ O ₃ is used as the dielectric, and the relative dielectric constant is 9.0 and the thickness is 1 mm.
At this time, the relationship between the sheath voltage V ₀ and the electrode voltage V _rf can be obtained by the following Expression 5.

V ₀ = V _rf /(1+0.196 d _s ) Equation 5

The calculation result of Equation 5 is shown in FIG. As shown in FIG. 10, the sheath voltage is less likely to be applied as the sheath width becomes larger, and a higher frequency voltage needs to be applied. Up to now, a one-dimensional model has been established to verify the effects of the present invention. A method of applying the present invention to a two-dimensional plane on an actual Si substrate (Si wafer) 110 will be described below.
First, with reference to FIG. 11, the example of arrangement | positioning of the high frequency electrode 201 in the board | substrate support stand 111 which comprises Example 1 of this invention is demonstrated. FIG. 11 is an explanatory diagram for explaining an arrangement example of the high-frequency electrodes 201 on the substrate support 111 according to the first embodiment of the present invention.
As shown in FIG. 11, the arrangement of the plurality of high-frequency electrodes 201 is determined in the arrangement of the X and Y coordinate systems as shown in FIG. 11 so as to be within the area of the circular substrate support 111, and the coordinates of each high-frequency electrode 201 are ( m, n).

In the arrangement of the high-frequency electrodes 201 shown in FIG.
When a high frequency of V _mn = V ₀ sin (ωt + 2πmx _e / x ₀ ) is applied, a sheath wave traveling in the X direction can be obtained.
Further, when a high frequency of V _mn = V ₀ sin (ωt + 2πnx _e / x ₀ ) is applied, a sheath wave traveling in the Y direction can be obtained.
Furthermore, when a high frequency of V _mn = V ₀ sin (ωt + 2πmx _e / x ₀ ± 2πn · x _e / x ₀ ) is applied, a sheath wave traveling in an oblique 45 ° direction can be obtained. Hereinafter, the spatial vibration of the sheath is referred to as a sheath wave.
By applying the above method, it is possible to obtain sheath waves traveling in various directions.
In order to irradiate ions on the sidewalls of the pattern 110a shown in FIG. 14 formed in various directions on the substrate surface by plasma treatment, sheath waves in the X direction, Y direction, + 45 ° direction, and −45 ° direction are used. What is necessary is just to excite sequentially by a fixed time interval.
Further, the traveling direction of the sheath wave may be gradually rotated, and the obtained effect is exactly the same regardless of the traveling direction of the sheath wave.

On the other hand, in FIG. 11, the shape of the high-frequency electrode 201 is a square, but it may be an arbitrary shape such as a circle or a hexagon.
The arrangement method of the high frequency electrode 201 may be a concentric arrangement. In this arrangement, it is possible to obtain a sheath wave that goes from the center to the periphery or from the periphery to the center, and it is also possible to obtain a sheath wave that rotates in the θ direction.
Furthermore, it is also possible to perform ion incidence inclined in one direction by distorting the spatial sheath vibration into a triangular wave instead of a sine wave.

On the other hand, FIG. 12 is an explanatory diagram for explaining another example of the high-frequency power source and the phase control means according to the first embodiment of the present invention.
Up to this point, the plasma processing apparatus according to the first embodiment of the present invention in which a plurality of high-frequency power sources 202 are provided in a one-to-one relationship with a plurality of high-frequency electrodes 201 as shown in FIG. 1 has been described. A high-frequency power source 202a and a phase shifter 203a having a plurality of outputs may be used.
A plurality of outputs of the phase shifter 203a having a plurality of outputs are connected to the high-frequency electrodes 201 on a one-to-one basis, and outputs adjacent to the plurality of outputs are similarly different in phase.
As a form of the phase shifter 203a, a form using a capacitor or an inductor and a form combining two waves are conceivable, but any form may be used as long as the phase can be changed.

Next, with reference to FIG. 13, a modification in which the temperature of the substrate support 111 according to the first embodiment of the present invention is controlled will be described. FIG. 13 is an explanatory diagram for explaining a modification in which the temperature of the substrate support 111 according to the first embodiment of the present invention is controlled.
In this case, a wiring for applying a high frequency is taken out from the peripheral portion of the substrate, and the temperature control mechanism 205 may be attached to the central portion of the substrate support 111.
The temperature control mechanism 205 may be a heater block or a metal plate having a temperature-controlled liquid flow path 205a. In this case, in order to improve heat conduction, the dielectric in which the electrode is embedded is preferably an aluminum nitride high thermal conductivity material.
Further, in order to improve the heat conduction between the substrate support 111 and the Si substrate 110, undulations are provided on the surface of the substrate support 111 as necessary, and helium gas is introduced between the substrate support 111 and the Si substrate 110. A function may be provided.

Further, lamp heating from the upper part or the lower part may be used as the temperature control mechanism. However, in the case of lamp heating from the lower part, it is preferable that the substrate support 111 and the high-frequency electrode 201 are made of a transparent material.
In this case, quartz is preferable as the material of the substrate support 111, and ITO may be used as the material of the high-frequency electrode 201.
On the other hand, as application examples of Embodiment 1 of the present invention, removal of the sidewall protective film after dry etching, oxidation / nitridation of the pattern side surface and introduction of impurities, improvement of the coverage by oblique ion irradiation during plasma CVD, and densification of the film are considered. It is done.
In addition, since the maximum incident angle can be controlled according to the applied voltage condition, it can be applied to etching with a reverse taper shape.
Further, since the incidence rate of obliquely incident ions is higher than that of normal incidence, the entire etching back process and the ashing process have the advantages of increasing the etching rate and increasing the residue removal effect.

In the plasma processing apparatus of Example 1 of the present invention, by applying a high frequency having a specific phase difference to each high frequency electrode 201, the plasma potential and each high frequency electrode 201 are spatially distributed along the surface of the substrate support 111. The difference between the potential and the potential of the sheath vibrates, and the thickness and shape of the sheath vary variously.
As a result, since ions are accelerated perpendicularly to the interface between the plasma and the sheath, there are places where the ions are perpendicularly incident and obliquely incident on the Si substrate 110 as time passes. Ions can be incident on the substrate 110 from various directions.
For this reason, the phenomenon makes it easy to perform plasma treatment on the side surface of the Si substrate 110 without requiring restriction of the beam diameter or enlargement of the apparatus. Removal and modification can be performed, and higher performance can be realized.

Next, a second embodiment of the present invention applied to the removal of the sidewall protective film after the polysilicon etching will be described.
The plasma processing apparatus of Example 2 of the present invention uses the plasma processing apparatus (surface wave interference plasma processing apparatus) shown in FIG.
For the dielectric window 106, quartz having a diameter of 327 mm and a thickness of 13 mm was used. The slot antenna 105 has a configuration in which six slots are arranged radially every 60 °.
The pitch of the high-frequency electrodes 201 of the substrate support 111 was 5 mm, the high-frequency frequency was 200 kHz, and the sheath wave wavelength was 40 mm.

First, the Si substrate 110 immediately after the polysilicon etching was placed on the substrate support 111 and evacuated by a turbo molecular pump and a dry pump (not shown).
Next, 1000 sccm of O ₂ gas was introduced into the vacuum vessel 107, the variable conductance valve 109 was adjusted, and the pressure was set to 100 Pa.
Next, a 3.0 kW microwave was oscillated from a 2.45 GHz microwave power source. At this time, microwaves were radiated from the slot antenna 105 opened at the lower part of the annular waveguide into the vacuum vessel 107 through the dielectric window 106, and surface wave plasma was generated.
The first wafer was processed for 60 seconds by applying a high frequency of the same phase at Vrf = 50 V to the substrate. The second wafer was processed for 60 seconds by applying a phase-modulated high frequency wave according to the present invention at Vrf = 50 V to the substrate.

After the processing, both wafer surfaces were observed using SEM, and the results were as follows. In the first wafer, a protruding residue remained on the pattern edge, and it was necessary to perform an amine-based stripping liquid treatment in the next step.
On the other hand, the second wafer had no pattern edge residue and the sidewall film was completely removed. Therefore, the next process of removing the amine-based stripping solution can be omitted, and the cost of the manufacturing process can be reduced.
When a phase-modulated high frequency wave according to the present invention is applied to the substrate at Vrf = 50 V and the treatment is performed for 60 seconds, it is possible to obtain a phenomenon in which ions are incident on the substrate from various directions including the side surface. The film on the side surface of the substrate could be completely removed.
As a result, it was confirmed that the plasma processing apparatus of this example was able to satisfactorily process the surface and side surfaces of the substrate without increasing the size of the apparatus, and clearly realized higher performance. It was.

Next, Embodiment 3 of the present invention applied to the removal of the sidewall protective film after the Al wiring etching will be described.
As the plasma processing apparatus of Example 3 of the present invention, the plasma processing apparatus (surface wave interference plasma processing apparatus) shown in FIG. 1 was used.
The dielectric window 106 is made of quartz having a diameter of 327 mm and a thickness of 13 mm. The slot antenna 105 has a shape in which six slots are arranged radially every 60 °.
The pitch of the high-frequency electrodes 201 of the substrate support 111 was 5 mm, the high-frequency frequency was 100 kHz, and the wavelength of the sheath wave was 40 mm.

First, a silicon substrate having an Al film and a resist formed on its surface was placed on the substrate support 111 in the first processing chamber, and evacuated by a turbo molecular pump and a dry pump (not shown).
Next, 100 sccm of C12 gas and 50 sccm of BC13 were introduced into the vacuum vessel 107, the variable conductance valve 109 was adjusted, and the pressure was set to 5 Pa. Next, a 3.0 kW microwave was oscillated from a 2.45 GHz microwave power source.
At this time, microwaves were radiated from the slot antenna 105 opened at the lower part of the annular waveguide into the vacuum vessel 107 through the dielectric window 106, and surface wave plasma was generated.
At the same time, a high frequency of Vrf = 150 V in the same phase was applied to the high frequency electrode 201 of the substrate support 111 and the treatment was performed for 10 seconds under the above conditions.

Next, while maintaining the plasma, the C12 flow rate was changed to 100 sccm, the BC13 flow rate was changed to 10 sccm, and the pressure was changed to 10 Pa. After etching to the end point, 30% overetching was performed.
After the Al etching is completed, the wafer is transferred to the second processing chamber while maintaining the wafer in a vacuum, and after placing the wafer on the substrate support 111, 1000 sccm of O ₂ gas is introduced, and the variable conductance valve 109 is turned on. The pressure was set to 100 Pa by adjusting.
Next, a 3.0 kW microwave was oscillated from a 2.45 GHz microwave power source to generate plasma, and the resist was ashed.
The first wafer was processed for 60 seconds by applying a high frequency of the same phase at Vrf = 50 V to the substrate. The second wafer was processed for 60 seconds by applying a phase-modulated high frequency wave according to the present invention at Vrf = 50 V to the substrate.

After the treatment, both wafers were left in the atmosphere for 24 hours, and the surface was observed using SEM. The results were as follows. In the first wafer, protruding after-corrosion was observed on the side surface of the pattern.
On the other hand, it was found that the second wafer had no protrusions on the side surface of the pattern and chlorine on the side walls was completely removed. Therefore, the next process of removing the amine-based stripping solution can be omitted, and the cost of the manufacturing process can be reduced.
When a phase-modulated high frequency wave according to the present invention is applied to the substrate at Vrf = 50 V and the treatment is performed for 60 seconds, it is possible to obtain a phenomenon in which ions are incident on the substrate from various directions including the side surface. The film on the side surface of the substrate could be completely removed.
As a result, it was confirmed that the plasma processing apparatus of this example was able to perform the processing of the surface and side surfaces of the substrate satisfactorily without increasing the size of the apparatus, and clearly realized higher performance. It was.

Next, a fourth embodiment of the present invention applied to oxidation of the side surface of the polysilicon electrode will be described.
As the plasma processing apparatus of Example 4 of the present invention, the plasma processing apparatus (surface wave interference plasma processing apparatus) shown in FIG. 1 was used. The dielectric window 106 is made of quartz having a diameter of 327 mm and a thickness of 13 mm. The slot antenna 105 has a shape in which six slots are arranged radially every 60 °.
The pitch of the high-frequency electrodes 201 of the substrate support 111 was 5 mm, the high-frequency frequency was 100 kHz, and the wavelength of the sheath wave was 30 mm.

First, a silicon substrate with a polysilicon pattern was placed on the substrate support 111 and evacuated by a turbo molecular pump and a dry pump (not shown).
Next, 5 sccm of O ₂ gas and 95 sccm of He gas were introduced into the vacuum vessel 107, the variable conductance valve 109 was adjusted, and the pressure was set to 10 Pa. Next, a 1.0 kW microwave was oscillated from a 2.45 GHz microwave power source.
At this time, microwaves were radiated from the slot antenna 105 opened at the lower part of the annular waveguide into the vacuum vessel 107 through the dielectric window 106, and surface wave plasma was generated.
The first wafer was processed for 180 seconds by applying a high frequency of the same phase at Vrf = 40V to the substrate. Further, the second wafer was processed for 180 seconds by applying a phase-modulated high frequency according to the present invention at Vrf = 40 V to the substrate.

After the completion of the processing, the oxide film thicknesses on the upper surface and the side surface of the pattern were measured on the cross sections of both wafers using TEM. As a result, in the first wafer, the film thickness ratio between the upper surface and the side surface of the pattern was 1: 0.3.
On the other hand, in the second wafer, the film thickness ratio became 1: 0.85, and the film formation rate on the pattern side surface was greatly improved. This is a result of improving the film formation speed by causing ions to enter the side surface of the pattern by vibrating the sheath.
When a phase-modulated high frequency wave according to the present invention is applied to the substrate at Vrf = 40 V and processing is performed for 180 seconds, it is possible to obtain a phenomenon in which ions are incident on the substrate from various directions including side surfaces. An excellent oxide film could be formed on the side surface of the substrate.
As a result, it was confirmed that the plasma processing apparatus of this example was able to perform the processing of the surface and side surfaces of the substrate satisfactorily without increasing the size of the apparatus, and clearly realized higher performance. It was.

Next, a fifth embodiment of the present invention applied to nitridation of an oxide film formed on the side surface of a polysilicon electrode will be described.
As the plasma processing apparatus of Example 5 of the present invention, the plasma processing apparatus (surface wave interference plasma processing apparatus) shown in FIG. 1 was used.
The dielectric window 106 is made of quartz having a diameter of 327 mm and a thickness of 13 mm. The slot antenna 105 has a shape in which six slots are arranged radially every 60 °.
The pitch of the high-frequency electrodes 201 of the substrate support 111 was 5 mm, the high-frequency frequency was 100 kHz, and the wavelength of the sheath wave was 30 mm.

First, a silicon substrate having a polysilicon pattern formed on the substrate support 111 and having a 2 nm oxide film formed on the surface was placed, and evacuated by a turbo molecular pump and a dry pump (not shown).
Next, 100 sccm of N ₂ gas was introduced into the vacuum vessel 107, the variable conductance valve 109 was adjusted, and the pressure was set to 100 Pa.
Next, a 1.0 kW microwave was oscillated from a 2.45 GHz microwave power source. At this time, microwaves were radiated from the slot antenna 105 opened at the lower part of the annular waveguide into the vacuum vessel 107 through the dielectric window 106, and surface wave plasma was generated.
Next, a high frequency phase-modulated according to the present invention was applied to the substrate at Vrf = 40 V, and a treatment for 180 seconds was performed.

After the treatment was completed, the amount of nitrogen introduced on the upper and side surfaces of the pattern was measured using μ Auger. As a result, the nitrogen concentration ratio between the upper surface and the side surface of the pattern was 1: 0.7.
As described above, since the ions are incident on the side surface of the pattern by vibrating the sheath, nitrogen can be introduced into the silicon oxide film formed on the side surface of the pattern.
When a phase-modulated high frequency wave according to the present invention is applied to the substrate at Vrf = 40 V and the treatment is performed for 180 seconds, ions are incident on the substrate from various directions including the side surface, so that the substrate is exposed to the side surface. Good nitrogen can be introduced into the formed silicon oxide film.
As a result, it was confirmed that the plasma processing apparatus of this example was able to perform the processing of the surface and side surfaces of the substrate satisfactorily without increasing the size of the apparatus, and clearly realized higher performance. It was.

Next, Example 6 of the present invention applied to densification of the side surface of the plasma SiO ₂ film formed on the polysilicon electrode will be described.
As the plasma processing apparatus of Example 6 of the present invention, the plasma processing apparatus (surface wave interference plasma processing apparatus) shown in FIG. 1 was used.
The dielectric window 106 is made of quartz having a diameter of 327 mm and a thickness of 13 mm. The slot antenna 105 has a shape in which six slots are arranged radially every 60 °.
The pitch of the high-frequency electrodes 201 of the substrate support 111 was 5 mm, the high-frequency frequency was 100 kHz, and the wavelength of the sheath wave was 30 mm.

First, a silicon substrate on which a comb-shaped polysilicon pattern was formed was placed on the substrate support 111, and evacuated by a turbo molecular pump and a dry pump (not shown).
Next, 50 sccm of SiH ₄ and 100 sccm of N ₂ O gas were introduced into the vacuum vessel 107, the variable conductance valve 109 was adjusted, and the pressure was set to 100 Pa.
Next, a 1.0 kW microwave was oscillated from a 2.45 GHz microwave power source. At this time, microwaves were radiated from the slot antenna 105 opened at the lower part of the annular waveguide into the vacuum vessel 107 through the dielectric window 106, and surface wave plasma was generated.
The first wafer was subjected to film formation for 30 seconds by applying a high frequency of the same phase at Vrf = 40 V to the substrate. The second wafer was subjected to film formation for 30 seconds by applying a phase-modulated high frequency according to the present invention at Vrf = 40 V to the substrate.

When the film thickness of the flat surface was measured after the completion of the treatment, all were about 50 nm. Next, a _second polysilicon film is formed on the SiO ₂ , and the second polysilicon electrode is patterned so as to overlap with the first polysilicon electrode that is a comb shape. Created.
By measuring the withstand voltage of this capacitor, the withstand voltage of the SiO ₂ film on the side surface of the pattern can be evaluated. As a result, the withstand voltage of the first wafer was 12V, whereas the withstand voltage of the second wafer was improved to 13.2V.
This is considered to be because the film on the side surface is densified by the incidence of ions on the side surface of the pattern.
When a phase-modulated high frequency wave according to the present invention is applied to the substrate at Vrf = 40 V and a film forming process is performed for 30 seconds, ions are incident on the substrate from various directions including the side surfaces. It has become possible to obtain good pressure resistance for side film formation.
As a result, it was confirmed that the plasma processing apparatus of this example was able to perform the processing of the surface and side surfaces of the substrate satisfactorily without increasing the size of the apparatus, and clearly realized higher performance. It was.

It is explanatory drawing explaining the outline | summary and internal structure of the plasma processing apparatus of Example 1 of this invention. It is a principal part expansion explanatory drawing which expands and demonstrates the principal part of the plasma processing apparatus of Example 1 of this invention. It is explanatory drawing explaining an example of the application method of the output power of the high frequency power supply in the plasma processing apparatus of Example 1 of this invention, and the change of the sheath thickness of the substrate surface accompanying it, and the incident direction of ion. It is a graph which shows the result of having calculated the relationship between plasma density, sheath voltage, and sheath width based on Formula 1 of Example 1 of this invention. It is explanatory drawing which illustrates typically the mode of the wavelength of the spatial vibration of the sheath of Example 1 of this invention. It is a graph which shows the result of having calculated | required the maximum incident angle of ion based on the calculation result of the relationship between the plasma density of Example 1 of this invention, and a sheath voltage, and a sheath width. It is a graph which shows an example of the calculation result of the normalized ion flux in the case of the sheath of a prior art example. It is a graph which shows an example of the calculation result of the normalized ion flux in the case of the sine wave sheath of Example 1 of this invention. It is a graph which shows the relationship between the incident angle of ion and incident energy in the plasma processing apparatus of Example 1 of this invention. It is a graph which shows the relationship between the sheath width in the plasma processing apparatus of Example 1 of this invention, and the voltage concerning a sheath. It is explanatory drawing explaining the example of arrangement | positioning of the high frequency electrode in the board | substrate support stand of Example 1 of this invention. It is explanatory drawing explaining the other example of the high frequency power supply of Example 1 of this invention, and a phase control means. It is explanatory drawing explaining the modification which controls the temperature of the board | substrate support stand of Example 1 of this invention. It is explanatory drawing explaining the relationship between the conventional substrate surface and side wall protective film, and incident ion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 High frequency oscillator 102 Waveguide 103 Matching device 104 Annular waveguide 105 Slot antenna 106 Dielectric window 107 Vacuum vessel 108 Mass flow controller 109 Variable conductance valve 110 Si substrate (substrate)
DESCRIPTION OF SYMBOLS 111 Substrate support 110a Pattern 110b Side wall protective film 201 High frequency electrode 202 High frequency power supply 203 Phase control means 204 Ion 205 Temperature control mechanism 205a Flow path

Claims (10)

A vacuum vessel;
Exhaust means for exhausting the atmosphere of the vacuum vessel;
Gas introduction means for introducing gas into the vacuum vessel;
Plasma generating means for generating plasma in the vacuum vessel;
In a plasma processing apparatus having a substrate support means on which a substrate to be processed is placed,
A high frequency power source for applying a high frequency;
Phase control means for controlling the phase of the high frequency applied from the high frequency power supply;
The substrate support means has a plurality of electrodes to which a plurality of high frequencies whose phases are controlled are respectively applied,
The plasma processing apparatus, wherein the phase of the high frequency applied to each of the plurality of electrodes by the phase control means is shifted between adjacent electrodes.   The plasma processing apparatus according to claim 1, wherein the phase control unit includes a plurality of phase control units each having a single output and is applied by each of the plurality of high-frequency power sources.   The plasma processing apparatus according to claim 1, wherein the phase control unit includes a phase shifter having a plurality of outputs and is applied by a single high-frequency power source.   The plasma processing apparatus according to claim 1, wherein a pitch of the electrodes is 10 mm or less.   The plasma processing apparatus according to any one of claims 1 to 4, wherein the frequency of the high frequency is 10 MHz or less. In a plasma processing method of generating plasma in a vacuum vessel by plasma generating means and performing plasma processing of a substrate to be processed supported by a substrate support means in the vacuum vessel,
A high frequency output process for outputting a high frequency; and
A phase control step for performing phase control for differentiating the phases of the adjacent high-frequency waves;
An individual high frequency application step of individually applying a plurality of high frequencies having different phases between the adjacent sides after the phase control to a plurality of electrodes configured in the substrate support means,
A plasma processing method comprising:   7. The plasma processing method according to claim 6, wherein in the phase control step, the phase control of the high frequency output from each of a plurality of high frequency power sources is performed using a plurality of phase control means having a single output.   The phase control step performs high-frequency phase control output from a single high-frequency power source using a phase shifter having a plurality of outputs, and at least two types of a plurality of adjacent phases differ by the phase shifter. The plasma processing method according to claim 6, wherein a high frequency is generated.   The plasma processing method according to claim 6, wherein a pitch of each electrode is 10 mm or less.   The plasma processing method according to any one of claims 6 to 9, wherein the frequency of the high frequency is 10 MHz or less.

Images