JPH08148486A - Plasma treatment device - Google Patents

Abstract

PURPOSE: To provide a plasma treatment device which is excellent in film deposition rate, causes less damage to a work, and is enhanced in product yield. CONSTITUTION: A plasma treatment device is equipped with a vacuum chamber 8 provided with a pad 26 where a work W is mounted, a magnetic field imposing means 22 which imposes a magnetic field on the vacuum chamber 8, a plasma generating high-frequency power feed means 16 which applies plasma generating high-frequency electric power onto the vacuum chamber 8, a plasma absorption high-frequency power feed means 32 which applies a high-frequency power to the pad 26 so as to absorb generated plasma ions, wherein the frequency of the plasma absorption high-frequency power feed means 32 is set lower than the oscillation frequency of plasma ions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus using electron cyclotron resonance.

[0002]

2. Description of the Related Art Generally, in a manufacturing process of a semiconductor integrated circuit, a target integrated circuit is formed by repeatedly performing a conductor or non-conductor thin film forming operation and an etching operation on a semiconductor wafer. Aluminum wiring is mainly used as the wiring pattern of the integrated circuit, and the material of the interlayer insulating film for insulating this is, for example, SiO 2.
₂ (silicon oxide film) is used, and since the film quality is good as a method for forming the SiO ₂ film, ECR (Electron Cyclotrr) combining microwave and magnetic field is used.
on Resonance) plasma treatment tends to be adopted.

[0003] guiding the microwaves of the ECR plasma treatment as a plasma processing apparatus for performing are disclosed in, for example, JP-A 4-257224 and JP 4-271122, a treatment chamber for example 2.45 GHz _z It is supplied through a pipe and at the same time has a predetermined size, for example, 875
By applying a Gaussian magnetic field, the gas is made into a high-density plasma by the interaction (resonance) between the microwave and the magnetic field, and the reactive gas is activated by this plasma to form ion species, and sputter etching is performed on the surface of the semiconductor wafer. Deposition is performed simultaneously. The contradictory sputter etching operation and the deposition operation are controlled so that the deposition operation is dominant in a macroscopic view, and the deposition is performed as a whole.

[0004] When performing such an ECR plasma process is generally by applying a negative high-frequency bias voltage of the mounting table (susceptor) for example 13.56MH _z mounting the wafer, plus wafer side ion Is attracted as much as possible to maximize the sputter effect. The reason for this is that when the mounting table is of no bias, only the deposition is performed first, so the probability of voids occurring between the aluminum wirings is high, whereas when a negative bias is applied as described above. Since the sputter etching is performed and the deposition is performed at the same time, the deposits on the edges of the aluminum wiring are mainly affected by the sputter etching, and the film formation on this portion is suppressed. This is because the width becomes wider and sufficient deposition is performed to a deep portion, so that filling with few voids becomes possible.

Further, by performing such ECR plasma treatment, the unevenness of the surface of the insulating film caused by the wiring, the electrodes, etc. is flattened without the need for a separate flattening treatment, and the insulating characteristics can be improved. A multi-layer structure can also be formed.

[0006]

However, in the ECR plasma treatment as described above, if the space between the aluminum wirings is simply buried, there is no problem so far, but in consideration of mass productivity, the deposition efficiency is poor, and There is a problem that the damage given to the wafer surface is also large.

That is, regarding the deposition efficiency, the effective filling rate is determined by the difference between the sputter etching amount and the deposition amount, but these two rates are not balanced, and for example, if the deposition action is too strong, many voids tend to occur. ,
Conversely, if the sputter etching action is too strong, the aluminum electrode will be scraped. In this way, it is necessary to balance the two rates, but the deposition rate can be considerably increased or decreased as necessary, but the sputter etching rate cannot be sufficiently increased with respect to the deposition rate, and therefore, In the actual processing, the sputter etching rate limited the effective filling rate, and the deposition efficiency was not sufficient.

The state at this time is shown in FIGS. 6 and 7. Figure 6
Indicates the sputter etching rate (right vertical axis) and the film formation rate (left vertical axis) of the thermal oxide film at each portion from the wafer center to the peripheral portion. FIG. 7 shows the wafer center portion, which is 30 mm and 60 mm away from this in the radial direction. It is a cross-sectional schematic diagram of the wafer in a position. Incidentally, 13.56MH _z is to the wafer mounting table
The negative high frequency bias voltage is applied.

As is clear from FIG. 5, the sputter etching amount (right vertical axis) decreases as the distance from the wafer center increases, and at the same time, the film formation amount (left vertical axis) also decreases. Further, in the wafer cross-sectional view (FIG. 7 (A)) of the point P1 which is the center of the wafer, there is almost no void between the aluminum electrodes 3 and 3, but the wafer of the point P2 which is about 30 mm away from the center of the wafer. In the cross-sectional view (FIG. 7 (B)), a slight void 2 is generated, and further 60 from the center of the wafer.
A large void 4 is generated in the wafer cross-sectional view (FIG. 7C) at the point P3 which is the wafer peripheral portion separated by mm. That is, the lower the sputter etching rate,
Voids are also generated and the film forming rate is reduced.

Damage to the wafer surface occurs as follows. Generally, the gate oxide film of a semiconductor device is 50-100Å
It is very thin and is destroyed by a potential difference of, for example, about 10 V. However, in the above-mentioned ECR plasma processing, the plasma density on the wafer becomes non-uniform in the surface, and the non-uniformity of the potential distribution of the plasma is directly reflected on the wafer surface. Will be done. For example, when a relatively large number of plasma ions gather above the wafer center and a small number of plasma ions above the wafer edge, a potential difference occurs between the wafer center and the edge, and when this exceeds a limit value, the gate is charged as described above. The oxide film or the like causes a dielectric breakdown and is damaged. Therefore, there has been a problem that the yield of products is considerably reduced.

The present invention has been made to pay attention to the above problems and to solve them effectively. An object of the present invention is to provide a plasma processing apparatus which has good deposition efficiency for film formation, has less damage, and can improve product yield.

[0012]

As a result of earnest studies, the present inventors have found that in order to improve the deposition efficiency without generating voids, the sputter etching rate that controls the deposition efficiency should be improved. In order to increase this rate and reduce damage, the frequency of the high frequency bias voltage supplied to the mounting table may be set to be equal to or lower than the oscillation frequency of the plasma ions so that the plasma ions are caused to oscillate by following the attraction frequency. It was made by obtaining the knowledge.

That is, according to the present invention, a vacuum container having a mounting table for mounting an object to be processed therein, a magnetic field applying means for applying a magnetic field to the vacuum container, and a plasma generating device in the vacuum container. In the plasma processing high-frequency supply means for applying a high-frequency for plasma generation, and a high-frequency supply means for plasma-suction for applying a high-frequency to the mounting table in order to attract the generated plasma ions. The frequency of the means is set to a frequency equal to or lower than the oscillation frequency of the plasma ions.

[0014]

Since the present invention is constructed as described above, the plasma ions in the vacuum vessel vibrate sufficiently following the frequency given from the high-frequency suction supply means.
As a result, the energy of the ions colliding with the surface of the object to be processed is increased and the etching rate is also increased. Therefore, the film formation rate can be improved by balancing this, so that the deposition efficiency can be significantly improved as a whole. In this case, since the etching rate is relatively high, for example, the frontage between the aluminum electrodes can be maintained sufficiently wide, the film-forming material can be introduced to a deep portion, and the generation of voids can be suppressed.

Furthermore, since the plasma ions can be made to oscillate by following the frequency for attracting ions, positive and negative charges alternately enter the surface of the object to be processed in accordance with the frequency of the object to be processed. The electric charges of are immediately neutralized, and it is possible to prevent a large potential difference from occurring in the surface of the object to be processed, and prevent the gate oxide film and the like from being dielectrically broken down.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the plasma processing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view showing a plasma processing apparatus according to the present invention, and FIG. 2 is a graph showing the relationship between the frequency of a plasma suction high-frequency supplying means and a sputter etching rate.

As shown in the figure, this plasma processing apparatus 6
Has a stepped vacuum container 8 formed of, for example, aluminum. The vacuum container 8 is located above and is connected to a plasma chamber 10 for generating plasma, which is connected to and communicate with the plasma chamber 10 below. The interior is partitioned into a chamber 11.

The upper end of the vacuum container 8 is opened, and a transparent window 12 made of a material that transmits microwaves such as quartz is hermetically provided in this portion through a sealing member 14 such as an O-ring. The vacuum state in the container 8 is maintained. On the outside of the transmission window 12, for example, a waveguide 18 connected to the RF source 16 as a plasma generation high frequency supplying means 2.45 GHz _Z are provided, guide the high frequency generated in the high frequency source 16 It can be guided by the wave tube 18 and introduced into the plasma chamber 10 through the transmission window 12.

Plasma gas nozzles 20 are evenly arranged along the circumferential direction on the side wall defining the plasma chamber 10.
A plasma gas source (not shown), for example, an Ar gas source and an O ₂ gas source, is connected to the nozzle 20, and a plasma gas such as Ar gas or O ₂ gas is evenly provided in the upper part of the plasma chamber 10. Can be supplied to. It should be noted that only two nozzles 20 are shown in the drawing in order to prevent complication of the drawing, but more nozzles are actually provided. In addition, on the outer periphery of the side wall that divides the plasma chamber 10,
A ring-shaped electromagnetic coil 22, for example, is arranged as a magnetic field applying means in close proximity to the plasma chamber 10.
For example, a magnetic field B of, for example, 875 Gauss from the upper side to the lower side can be formed therein, and the ECR plasma condition is satisfied. A permanent magnet may be used instead of the electromagnetic coil 22.

By thus forming the frequency-controlled microwave and the magnetic field B in the plasma chamber 10, the interaction between them causes a resonance action in the introduced gas at the above-mentioned frequency, so that the plasma has a high density. Will be formed. That is, this device constitutes an electron cyclotron resonance (ECR) plasma processing device. On the other hand, in the reaction chamber 11, there is provided a mounting table 26 made of aluminum as a susceptor supported on the bottom of the container via an insulating material 24, and the mounting surface on the upper surface is, for example, an electrostatic chuck 28. The semiconductor wafer W, which is the object to be processed, is suction-held via the.

The mounting table 26 is provided with, for example, a ceramic heater 30 for heating the wafer W to a predetermined temperature, a pusher pin (not shown), and the like. Further, a high frequency source 32 as a high frequency supplying means for plasma suction, which is a feature of the present invention, is connected to the mounting table 26 via a blocking capacitor 31, and a negative bias voltage for attracting ions to the wafer W is applied. Is applied. The frequency of this high-frequency source 32 is 13.
In 56MH _z, not being set in vibration frequency and equal to or less frequency plasma ion in the reaction chamber 11.

The oscillation frequency of the plasma ions, ion density, the internal pressure is determined by the temperature, the highest is approximately 10 MHz _z is in the process conditions used in present circumstances, therefore, the frequency of the high frequency source 32 10 MHz _z or less, preferably set to be about 2 MH _z. A reaction gas introduction nozzle 34 for introducing, for example, silane (SiH ₄ ) as a reaction gas into the reaction chamber 11 is provided on a side wall of the reaction chamber 11, and the inside of the reaction chamber 11 is opened when the wafer W is loaded and unloaded. A gate valve 36 is provided so as to be airtightly openable and closable. The reaction gas introduction nozzles 34 may be evenly arranged in the circumferential direction of the container so as to uniformly introduce the gas into the reaction chamber 11.

An exhaust port 38 connected to a vacuum pump (not shown) is provided at the bottom of the vacuum container 8 so that the atmosphere in the container can be uniformly exhausted from the bottom exhaust port 38. . The vacuum container 8 itself is grounded to zero potential.

Next, the operation of the present embodiment configured as described above will be described. First, the gate valve 36 provided on the side wall of the vacuum container 8 is opened, the wafer W is mounted on the mounting table 26 by a transfer arm (not shown), and the wafer W is suction-held by the electrostatic chuck 28. Next, this gate valve 3
After closing 6 to seal the inside, the internal atmosphere is exhausted from the exhaust port 38 to evacuate to a predetermined vacuum degree, and plasma such as O ₂ gas or Ar gas is generated from the plasma gas nozzle 20 into the plasma chamber 10. Of the plasma generation high-frequency source 16 and the plasma suction high-frequency source 3 while maintaining the internal pressure at a predetermined process pressure by introducing the silane gas into the reaction chamber 11 from the reaction gas introduction nozzle 34 while introducing the working gas.
2 is driven to start the film forming process of SiO ₂ on the wafer W.

2.4 from high frequency source 16 for plasma generation
A high frequency of 5 GHz is conveyed through the waveguide 18 and reaches the ceiling of the vacuum container 8, where it passes through the transparent window 12 and the microwave 40 is introduced into the plasma chamber 10. In the plasma chamber 10, a magnetic field B generated by an electromagnetic coil 22 provided outside the plasma chamber 10 is applied from the upper side to the lower side with a strength of, for example, 875 Gauss, and the magnetic field B and the microwave 40. The interaction with and induces E (electric field) × B (magnetic field) to generate electron cyclotron resonance, and the Ar gas or O ₂ gas is converted into plasma and densified by the resonance. The high-density plasma generated in the plasma chamber 10 is sucked by the plasma suction high-frequency source 32 to the mounting table 11 to which a negative high-frequency bias voltage is applied, descends, and flows into the reaction chamber 11.

The plasma ions flowing into the reaction chamber 11 activate the SiH ₄ gas, which is the film-forming gas supplied thereto, to form active species, and form Si on the wafer surface.
A film of O ₂ will be formed. As mentioned above, this EC
In the R film formation process, sputter etching and deposition (deposition) proceed at the same time, and the deposition is controlled so that the deposition becomes more dominant. It is designed to perform a flattening process.

In this case, as described above with reference to FIG. 6, in the peripheral portion of the wafer having a low sputter etching rate, the film forming rate is low and the probability of voids occurring between the electrodes is high. That is, in order to increase the effective filling speed and perform good filling, it is necessary to increase the sputter etching amount while balancing the sputter etching amount and the deposition amount.
There was a limit to this in the negative bias high frequency voltage of MHz. On the other hand, in the present invention, the negative bias voltage for plasma attraction applied to the mounting table 26 is equal to or lower than the vibration frequency of the plasma ions in the plasma chamber 10 or the reaction chamber 11, for example, a high frequency of 2 MHz. Therefore, the sputter etching amount can be increased beyond the conventional upper limit amount, and therefore the deposition amount that is relatively easy to control by balancing this can be increased, resulting in a high effective embedding speed. It is possible (improvement in mass productivity) to obtain a film of good quality without voids. In addition, damage to the wafer surface from plasma ions can be reduced, and as a result, product yield can be improved.

The reason why the sputter etching efficiency can be improved by applying a negative bias having a frequency lower than the oscillation frequency of plasma ions to the mounting table in this manner is presumed as follows. That is, as in the conventional case, a frequency higher than the vibration frequency of plasma ions, for example, 1
When applied to the mounting table frequency of 3.56MHz, can not vibrate following plasma ion frequency is too high, whereupon the surface of the wafer to 0V as shown in FIG. 4 DC bias voltage V _DC to the upper The component appears, and the potential difference of the voltage V _DC causes the ions to collide with the wafer surface to perform sputter etching. And this voltage V _DC is
Since it is lower than the high frequency voltage V ₀ for attracting ions, the sputter etching amount does not become so large.

On the other hand, in the present invention, the high frequency for ion attraction is set to be equal to or lower than the vibration frequency of the plasma ions as described above, so that the plasma ions vibrate following this frequency. It will be. Then, as shown in FIG. 4, the DC bias component that has been conventionally generated is not generated, and therefore, the plasma ions have a potential difference V ₀ substantially the same as the peak-to-peak amplitude of the high frequency for ion attraction. And the sputter etching is performed.

By thus setting the high frequency for ion attraction to be equal to or lower than the oscillation frequency of plasma ions, the potential difference with respect to ions during sputter etching can be increased and collision energy can be increased, so that the amount of sputter etching can be increased. . FIG. 2 is a graph showing the relationship between the frequency f of the negative bias voltage applied to the mounting table and the plasma sputter etching rate.
Is higher than the vibration frequency fi of the plasma ions, the sputter etching rate is high, but if the frequency exceeds this frequency, the etching rate sharply decreases, which is not preferable.

The vibration frequency of plasma ions is uniquely determined by the density of plasma, process pressure, gas type, temperature, etc., but the highest is about 10 MHz under the processing conditions generally performed at present. The processing conditions are
For example, SiH ₄ is used as a gas, and the plasma density, process pressure, and plasma ion temperature are 10 ¹⁰ to 1 respectively.
It is 0 ¹¹ cm ⁻³ , 5 mTorr or less, and 0.1 eV or less.

Further, if the frequency of the high frequency for ion attraction is too low, sputter etching cannot be performed, and the frequency is set to 1 MHz or more. The reason for this is that this high frequency power for negative bias must be introduced to the wafer via the electrostatic chuck that is an insulating material, but if the frequency is reduced below 1 MHz, the impedance at this electrostatic chuck portion becomes large. This is because it becomes impossible to introduce high frequency power into the wafer. Therefore, the frequency of the high frequency source for negative bias is 1M.
It is set within the range of not less than 10 Hz and not less than Hz.

The process conditions in this embodiment are SiH
The flow rates of ₄ , O ₂ and Ar are 44 SCCM and 56, respectively.
SCCM and 110 SCCM. The process pressure is 7.5 mTorr, and the high frequency source 16 for plasma generation is 2.
Its power is 1100 W at 45 GHz, and the high-frequency source 32 for plasma suction is 2 MHz and its power is 1000 W. The effective deposition rate at this time is 1700Å
/ Min was obtained, and good results could be obtained. Figure 3 shows the frequency of the high frequency source for plasma suction at 13.56 MHz.
It is a graph comparing the sputter etching rate (average value) when set to (conventional device) and 2 MHz (device of the present invention), and the rate at 13.56 MHz is used as a reference. As is clear from this graph, in the case of the device of the present invention in which the frequency is 2 MHz, regardless of the supplied power,
The etching rate is 1.8 times higher than that of the conventional device.

By performing the ECR film forming process under the process condition showing such a high etching rate, the effective filling speed becomes high as described above, the mass productivity can be improved, and the film can be formed with good quality without voids. Obtainable. FIG. 5 is a schematic diagram for explaining the situation at this time, and when the bias voltage is set to 2 MHz and a film of SiO ₂ is formed on the surface of the wafer W, the shoulder portions, that is, the edge portions of the aluminum electrodes 3 and 3. Since the film forming portion 42A (shown by the broken line in the figure) deposited on the portions corresponding to 3A and 3A is efficiently sputter-etched, the aperture 46 of the recess 44 is always kept large, and therefore, the recess 44 is activated to the deep portion. It is possible to form a film so that seeds do not enter and voids are not generated.

By balancing and increasing the deposition amount in response to the increase in the etching amount, the effective embedding speed can be increased and the mass productivity can be improved. In this regard, the effective embedding speed of the conventional device was 1600Å / min,
In the case of the device of the present invention, it could be improved to 2400 Å / min.

Further, by setting the frequency of the plasma suction high frequency source to be equal to or lower than the vibration frequency of the plasma ions, the plasma ions vibrate following the ion drawing high frequency as described with reference to FIG. Since the positive ions and the negative ions intrude into the wafer surface alternately, even if a potential difference occurs in the wafer surface as a result of a biased plasma distribution above the wafer surface, the positive and negative ions described above By alternately invading, the electric potential on the wafer surface is neutralized and this potential difference is eliminated. Therefore, a large potential difference that causes dielectric breakdown of the gate oxide film, etc. does not occur, and the product yield is improved. You can also

[0037] In this regard, in the conventional apparatus using the frequency of 13.56MH _Z is the product yield was about 40%, to improve to about 90% in the device of the present invention using a frequency of 2MHz I was able to. In the above embodiment, using a 2.45 GHz _z as the frequency of the high frequency source 16 for generating plasma to generate electrons cyclotron resonance has been set the strength of the magnetic field at that time 875 gauss, these values There is no limitation, and a value obtained by dividing these values by a multiple of 2 or a value obtained by multiplying them may be used. For example divided by the 2, i.e. the frequency of 1.225GH _z 43
A magnetic field of 7.5 Gauss may be used.

In the present embodiment, the so-called face-up type apparatus in which the wafer surface is directed upward has been described as an example, but the present invention is not limited to this, and the so-called upside-down apparatus shown in FIG. Of course, it can be applied to a face-down type device.

Next, the related art of the present invention will be described. For example, an insulating film between aluminum wirings is formed by the film formation by the ECR plasma processing as described above, and the insulating film is formed by SOG (Spi).
(n On Glass) film is used as a base film, it is necessary to form a film having excellent water permeation resistance and a small change in stress in a uniform state. There is an improvement in throughput due to particles and in-situ cleaning, and these need to be improved.

Conventionally, flattening of the interlayer insulating film is performed by plasma CV.
I have dealt with the combination of D / etchback / SOG,
This planarization has become an even more important issue with the multi-layer wiring of devices. By the way, SOG inherently has problems such as metal loss, corrosion, and deterioration of hot carrier resistance. In order to avoid these problems with future miniaturization, the water content of SOG is low, and the water permeation resistance is high. A highly resistant underlayer is required.

Under such circumstances, the SiO ₂ film using ECR plasma can be applied as a highly reliable interlayer insulating film. This ECR plasma SiO ₂
The film is not only SOG but also TEOS / O ₃ base film and CM
P (Chemical Mechanical Pol)
It can also be applied to an embedding process compatible with ashing.

FIG. 8 is a cross-sectional view showing an ECR plasma processing apparatus for carrying out the above-mentioned processing, which has a face-down structure in which the wafer surface is supported downward. As described above, it goes without saying that the above-described ECR plasma processing apparatus of the present invention may be used to configure the apparatus of the present invention. In the figure, 50 is a vacuum container, in which, for example, a plasma chamber 52 for introducing O ₂ gas and Ar gas,
It is divided into a reaction chamber 54 into which SiH ₄ gas is introduced. In this face-down structure, the reaction chamber 54 is the plasma chamber 52.
Is located above.

On the side of the plasma chamber 52, a transparent window 5 made of quartz is provided.
6 to generate a magnetic field of predetermined strength within the electromagnetic coil 58 disposed in the peripheral portion for example with microwaves 2.45 GHz _z is introduced through, the ECR plasma conditions due to the interaction of the magnetic field and the microwave Designed to meet. Further, cooler means 60 for flowing cooling water for cooling the side wall is provided on the side of the plasma chamber 52.

Inside the reaction chamber 52, a stage 64 (corresponding to a mounting table) having an electrostatic chuck 62 at the lower end is provided so as to project downward from the ceiling, and the wafer W is placed at the lower end. Holds by adsorption. A high frequency bias power source 66 capable of applying up to 2 KW is connected to the stage 64, and a heating means (not shown) for heating the wafer to a predetermined temperature is also provided. Then, the reaction gas, that is, SiH _4, is supplied into the reaction chamber 52 from the gas introduction nozzles 68 that are evenly arranged. The inside of the reaction chamber 52 is evacuated from the exhaust port 70 by two turbo molecular pumps (not shown) at a rate of, for example, 500 l / sec.

A plasma SiO ₂ film is formed as an SOG underlayer using the apparatus as described above.
The process steps are performed in substantially the same manner as described in the present invention. In this case, the frequency of negative bias high frequency voltage applied to the stage 64, may be limited without example 13.56MH _z below 10 MHz _z.

[0046]

As described above, according to the plasma processing apparatus of the present invention, the following excellent operational effects can be exhibited. The frequency of the bias high frequency voltage for plasma suction supplied to the mounting table when performing the film formation process using ECR plasma was set to be equal to or lower than the oscillation frequency of the plasma ions. The plasma ions can be oscillated by following the frequency. Therefore, the sputter etching rate that determines the film formation efficiency can be increased, so that a film having good film quality can be efficiently deposited on the surface of the target object. Further, by causing the plasma ions to follow the frequency of the high frequency for plasma suction and vibrate as described above,
Since positive ions and negative ions alternately enter the surface of the object to be processed, even if the plasma is unevenly distributed directly above the surface of the object to be processed, the electric charges existing on the surface of the object to be processed are neutralized. It is possible to suppress the occurrence of damage such as dielectric breakdown on the surface of the object to be processed, and it is possible to significantly improve the product yield.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a plasma processing apparatus according to the present invention.

FIG. 2 is a graph showing the relationship between the frequency of the plasma suction high-frequency supply means and the sputter etching rate.

FIG. 3 shows that the frequency of the high frequency source for plasma suction is 13.5.
6 is a graph comparing sputter etching rates (average values) when set to 6 MHz and 2 MHz.

FIG. 4 is an explanatory diagram for explaining a state of a potential on a surface of an object to be processed.

FIG. 5 is a schematic diagram for explaining a film forming process by the plasma processing apparatus of the present invention.

FIG. 6 is a graph showing a sputter etching rate and a film formation rate during film formation by a conventional plasma processing apparatus.

FIG. 7 is a schematic diagram schematically showing a film formation state at each point in the graph shown in FIG.

FIG. 8 is a cross-sectional view showing a plasma processing apparatus for explaining the related art of the present invention.

[Explanation of symbols]

 3 Aluminum Electrode 6 Plasma Processing Device 8 Vacuum Container 10 Plasma Chamber 11 Reaction Chamber 12 Transmission Window 16 High Frequency Supply Means for Plasma Generation 18 Waveguide 20 Plasma Gas Nozzle 22 Electromagnetic Coil (Magnetic Field Applying Means) 26 Mounting Table 32 High Frequency Supply for Plasma Suction Means 34 Reactive Gas Introducing Nozzle 40 Microwave B Magnetic Field W Semiconductor Wafer (Processing Object)

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/31 C 21/68 R H05H 1/46 C 9216-2G // G01R 33/64 G01N 24/14 B (72) Inventor Akira Suzuki 5-3-6 Akasaka, Minato-ku, Tokyo Within Tokyo Electron Ltd.

Claims (2)

[Claims] 1. A vacuum container having a mounting table for mounting an object to be processed therein, a magnetic field applying means for applying a magnetic field in the vacuum container, and a high frequency for plasma generation in the vacuum container. In the plasma processing apparatus having a plasma generation high-frequency supply means and a plasma suction high-frequency supply means for applying a high frequency to the mounting table to attract the generated plasma ions, the frequency of the plasma suction high-frequency supply means A plasma processing apparatus, wherein the frequency is set to be equal to or lower than the vibration frequency of the plasma ions. Frequency of claim 2 wherein said plasma suction microwave supplying means, a plasma processing apparatus according to claim 1, characterized in that the predetermined circumference index in the range of 1 MH _Z of 10 MHz _Z.