JP2009081312A - Surface treatment method and plasma treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treatment method capable of obtaining a treatment layer having a uniform thickness even when sections with relatively short-sized pitches are formed in an irregular section formed on the surface of a substance to be treated and plasma treatment equipment. <P>SOLUTION: In the surface treatment method, a pressure in a treatment chamber is made smaller than an atmospheric pressure, a reaction gas is introduced into the treatment chamber, a plasma is generated in the treatment chamber and the reaction gas is decomposed and activated by the plasma. In the surface treatment method, the substance to be treated is treated while controlling the quantity of charges on the surface of the substance to be treated by adjusting the electric field of a charge-transmission control section fitted between the plasma and the substance to be treated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface treatment method and a plasma treatment apparatus for an object to be treated.

For example, as in the case of oxidizing the surface of a silicon substrate, a plasma processing method is known as a method for processing the surface of an object to be processed (see, for example, Patent Document 1).
The plasma treatment method can be typically performed at a low temperature of 500 ° C. or lower, and can suppress the deterioration of the surface of the object to be processed and the generation of thermal stress.

Further, a plasma processing apparatus capable of plasma processing the surface of an object to be processed has been proposed (see, for example, Patent Document 2).
In the plasma processing apparatus disclosed in Patent Document 2, a perforated plate capable of shielding charged particles is provided between a plasma generation region and an object to be processed, and the opening of the hole can be adjusted. Thus, the in-plane uniformity of processing can be improved.

However, in the techniques disclosed in Patent Documents 1 and 2, consideration is not given to the pitch dimension of the uneven portion formed on the surface, and the uneven portion is provided with a portion having a relatively short pitch dimension. In some cases, a treatment layer having a uniform thickness may not be obtained.
JP 2004-266075 A JP-A-5-243185

  The present invention relates to a surface treatment method capable of obtaining a treatment layer having a uniform thickness even when a portion having a relatively short pitch dimension is provided on an uneven portion formed on the surface of a workpiece. A plasma processing apparatus is provided.

  According to one aspect of the present invention, the inside of the processing chamber is depressurized from the atmospheric pressure, a reaction gas is introduced into the processing chamber, a plasma is generated in the processing chamber, and the reaction gas is decomposed by the plasma. The object to be processed is processed while controlling the amount of charge on the surface of the object to be processed by activating and adjusting the electric field of the charge transmission control unit provided between the plasma and the object to be processed. A surface treatment method is provided.

  According to another aspect of the present invention, a processing chamber capable of maintaining an atmosphere depressurized from atmospheric pressure, means for generating plasma in the plasma generation space in the processing chamber, and in the plasma generation space A means for introducing a reactive gas; a stage provided below the plasma generation space on which an object to be processed is placed; a charge transmission control unit provided so as to cover an upper surface of the stage; and the charge transmission control There is provided a plasma processing apparatus comprising: a processing control unit having a power supply unit capable of controlling the voltage and polarity in the unit.

  According to the present invention, even when the uneven portion formed on the surface of the object to be processed is provided with a portion having a relatively short pitch dimension, the surface treatment can obtain a treatment layer having a uniform thickness. A method and plasma processing apparatus are provided.

Hereinafter, embodiments of the present invention will be illustrated with reference to the drawings.
FIG. 1 is a schematic cross-sectional view for illustrating a plasma processing apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the plasma processing apparatus 1 includes a processing chamber 2, a transmission window 3 made of a dielectric plate provided on the ceiling of the processing chamber 2, and a transmission window 3 outside the processing chamber 2. A microwave waveguide 4 provided on the upper surface, a shield 8 for defining a plasma generation space 7 below the transmission window 3, and an object to be processed such as a semiconductor wafer in the processing space 6 below the plasma generation space 7. A stage 5 for mounting and holding W; and a process control means 9 having a charge transmission control unit 9a provided so as to cover the upper surface of the stage 5 below the plasma generation space 7. .

  The processing chamber 2 can maintain a reduced-pressure atmosphere formed by exhaust means (not shown), and its wall surface is grounded. One end of an exhaust pipe 10 communicates with the bottom surface of the processing chamber 2, and an exhaust means (not shown) is connected to the other end of the exhaust pipe 10. A gas supply pipe 11 is provided so as to pass through the side wall of the processing chamber 2 and the shield 8. One end of the gas supply pipe 11 is opened toward a portion in the plasma generation space 7 where the plasma P is generated, and the other end is connected to a gas supply means (not shown) for supplying the reaction gas G into the plasma generation space 7. Has been.

  The microwave waveguide 4 has an H surface 4a that faces the transmission window 3 and is perpendicular to the electric field direction of the microwave M, and an E surface 4b that is perpendicular to the H surface 4a and parallel to the electric field direction of the microwave M. And a reflection surface 4c that reflects the microwave M provided in a direction perpendicular to the H surface 4a and the E surface 4b. Further, a slot antenna 12 is provided at a connection portion of the microwave waveguide 4 with the transmission window 3. The other end of the microwave waveguide 4 is connected to a microwave oscillator (not shown).

  The shield 8 has a cylindrical shape, one end of which is provided on the ceiling of the processing chamber 2, and the other end is opened toward the processing space 6. The shield 8 is disposed at a position in the processing chamber 2 such that the space inside the shield 8 becomes the plasma generation space 7. Therefore, the plasma generation space 7 can be defined by the shield 8, the diffusion of plasma products (such as charged particles and neutral active species) to the inner wall surface of the processing chamber 2 is suppressed, and the plasma products are covered. It is possible to efficiently supply the workpiece W.

The stage 5 is provided with an electrostatic chuck (not shown) for holding the workpiece W, temperature adjusting means (not shown) for adjusting the temperature of the workpiece W, and the like. The stage 5 is connected to the bottom surface of the processing chamber 2 through a stand 5a. Therefore, the stage 5 is grounded via the stand 5a and the processing chamber 2, and the workpiece W placed on the stage 5 is also grounded.
The processing control means 9 includes a charge transmission control unit 9a having conductivity, and a power supply unit 9b that is electrically connected to the charge transmission control unit 9a and controls the voltage and polarity in the charge transmission control unit 9a. ing.

The charge transmission control unit 9a is provided with a plurality of through holes. For example, the charge permeation control unit 9a can be a metal net (for example, a metal mesh, a grid-like conductive sheet, etc.) or a punching metal having a plurality of holes. The charge transmission control unit 9a can be made of a conductor such as metal, and can be made of, for example, stainless steel. In addition, when using plasma with high reactivity (for example, oxygen plasma mentioned later), it is preferable to perform surface treatment, such as gold | metal | money and gold plating excellent in corrosion resistance.
The power supply unit 9b can be, for example, a DC power supply that can change voltage and polarity (positive and negative). In this case, it is preferable to be able to control between about −100V to about 100V.

Next, the operation of the process control unit 9 will be illustrated.
Here, the voltage at the generation position of the plasma P is a potential of the plasma P + V ₀ (generally about +10 V), and the voltage at the position of the charge transmission control unit 9a is −V ₂ to + V _{1 which} can be controlled by the power supply unit 9b. The voltage in the range and the voltage at the surface position of the workpiece W are set to the ground voltage (0 V).

Potential space between the the voltage of the charge transmission control unit 9a and -V ₂ from the generation position of the plasma P to the position of the charge transmission control unit 9a descends toward the -V ₂ from the potential + V ₀ of the plasma P, It is considered that the potential in the space between the position of the charge transmission control unit 9a and the surface position of the workpiece W increases from −V ₂ toward the ground voltage (0V).

On the other hand, the potential space between the when the voltage of the charge transmission control unit 9a and + V ₁ from the generation position of the plasma P to the position of the charge transmission control unit 9a is raised towards + V ₁ from the potential + V ₀ of the plasma P, potential in the space between the position of the charge transmission control unit 9a to the surface position of the workpiece W is believed that descends toward the ground voltage (0V) from + V _1.
Further, even when the voltage of the charge transmission control unit 9a is varied within the range of −V ₂ to + V ₁ , it is considered that the potential can be similarly increased or decreased in each space.

  Here, the plasma product generated by the reaction gas G being excited and activated by the plasma P includes electrons, positively and negatively charged charged particles, neutral active species, and the like.

Therefore, if the voltage of the charge transmission control unit 9a is negative (for example, −V ₂ ), negatively charged charged particles and electrons out of the plasma product receive repulsive force, and thus can pass through the charge transmission control unit 9a. It is considered that it cannot be confined in the space between the generation position of the plasma P and the position of the charge transmission control unit 9a. In this case, the positively charged charged particles are captured by the charge permeation control unit 9a, and it is considered that only neutral active species can permeate the charge permeation control unit 9a.

Further, if the voltage of the charge transmission control unit 9a is positive (for example, + V ₁ ), the positively charged charged particles out of the plasma product receive a repulsive force and cannot pass through the charge transmission control unit 9a. It is considered that it is confined in the space between the position where P is generated and the position of the charge transmission control unit 9a. In this case, it is considered that negatively charged charged particles and electrons are captured by the charge transmission control unit 9a, and only neutral active species can pass through the charge transmission control unit 9a.
Thus, it is considered that charged particles and electrons can be eliminated by applying a voltage to the charge permeation control unit 9a.

  However, according to the knowledge obtained by the present inventor, when a positive voltage is applied to the charge transmission control unit 9a, positively charged particles enter the surface of the workpiece W, and a negative voltage is applied to the charge transmission control unit 9a. When applied, it has been found that electrons and negatively charged particles are incident on the surface of the workpiece W.

FIG. 2 is a schematic graph for illustrating the relationship between the voltage applied to the charge transmission control unit and the current flowing on the surface of the object to be processed.
As shown in FIG. 2, when a positive voltage is applied to the charge transmission control unit 9a, a positive current flows on the surface of the workpiece W. On the other hand, when a negative voltage is applied to the charge transmission control unit 9a, a negative current flows on the surface of the workpiece W. This is because when a positive voltage is applied to the charge transmission control unit 9a, positively charged charged particles enter the surface of the workpiece W, and when a negative voltage is applied to the charge transmission control unit 9a, the surface of the workpiece W is applied. It means that electrons or negatively charged particles are incident.

The reason is not necessarily clear, but can be considered as follows.
The charge transmission control unit 9a is provided with a plurality of holes, but the central portion of the hole is relatively weak in the action of an electric field, and charged particles and electrons easily pass through this portion. Further, depending on the speed of charged particles or electrons extracted from the plasma P, the charge transmission control unit 9a may be transmitted. For this reason, even if a voltage is applied to the charge transmission control unit 9a, some charged particles and electrons may be transmitted through the charge transmission control unit 9a.

That is, even when a negative voltage (for example, −V ₂ ) is applied to the charge transmission control unit 9a, some electrons and negatively charged particles are transmitted through the charge transmission control unit 9a and set to the ground voltage. Incident light is incident on the surface of the workpiece W. In this case, the positively charged charged particles are captured by the charge transmission control unit 9a and cannot pass through the charge transmission control unit 9a.

Further, even when a positive voltage (for example, + V ₁ ) is applied to the charge transmission control unit 9a, some positively charged charged particles pass through the charge transmission control unit 9a and are set to the ground voltage. Incident light is attracted to the surface of W. In this case, negatively charged charged particles and electrons are captured by the charge transmission control unit 9a and cannot pass through the charge transmission control unit 9a.

  In these cases, the amount of charged particles and electrons incident on the surface of the workpiece W can be increased by increasing the voltage of the charge transmission control unit 9a. Therefore, the amount of charged particles and electrons incident on the surface of the workpiece W can be controlled by controlling the voltage of the charge transmission control unit 9a. In addition, switching between positively charged particles and negatively charged particles / electrons can be performed by switching the polarity of the voltage applied to the charge transmission control unit 9a.

Next, an example of switching the polarity of the voltage applied to the charge transmission control unit 9a will be described.
For convenience of explanation, the case where the surface of the silicon substrate on which the pattern (uneven portion) is formed is oxidized will be described as an example. In this case, it is assumed that a portion having a relatively short pitch dimension is provided in the pattern.

FIG. 3 is a schematic graph for illustrating the oxidation treatment according to the comparative example.
FIG. 3 shows a case where the surface of the silicon substrate is oxidized using a plasma processing apparatus that does not include the processing control means 9.

  When the surface of the silicon substrate is oxidized using oxygen plasma, an oxide layer (SiO) is formed on the surface. Then, when an oxide layer which is an insulator is formed, electrons e are attached to the surface. The positively charged oxygen ions are accelerated by the action of the electric field by the attached electrons e and are drawn into the surface of the silicon substrate, so that the oxidation proceeds.

In this way, when the oxidation proceeds due to the action of the electric field by the electrons e attached to the surface, the distribution of pattern pitch dimensions (density difference in pattern form) affects the oxidation rate (processing speed). .
FIG. 4 is a schematic diagram for illustrating the influence of the pitch dimension of the pattern on the oxidation rate. As shown in FIG. 4, in a portion where the pattern pitch dimension is long and “sparse”, electrons e also fly to the “valley bottom” portion of the pattern, so that the oxide layer formed on the surface of the silicon (Si) substrate Electrons e are uniformly deposited on (SiO). On the other hand, in the “dense” part where the pitch dimension of the pattern is short, the electron e that has come in by the electron e attached near the opening of the pattern is rejected, so that the electron e adheres to the “valley bottom” part of the pattern. It becomes difficult. For this reason, if there is a distribution in the pitch dimension of the pattern (a density difference in the form of the pattern), the amount of adhesion of electrons e becomes non-uniform.

  Then, when the amount of attachment of electrons e is nonuniform, the electric field formed is also nonuniform, and the amount of positively charged oxygen ions drawn by the electric field is also nonuniform. As a result, in the portion where the pattern is “sparse”, the amount of oxygen ions to be drawn increases, so that the thickness of the oxide layer increases. On the other hand, in the portion where the pattern is “dense”, the amount of oxygen ions to be drawn is reduced, so that the thickness of the oxide layer is reduced.

  As described above, when the surface of a silicon substrate having a distribution of pattern pitch dimensions (density difference in pattern form) is oxidized, the thickness of the formed oxide layer varies, for example, as in a semiconductor device. In the case where an oxide layer having a uniform thickness is required, there is a risk of causing a malfunction such as malfunction.

FIG. 5 is a schematic graph for illustrating the case where the polarity of the voltage applied to the charge transmission control unit is switched.
As shown in FIG. 5, when a negative voltage is applied to the charge transmission control unit 9a, the oxidation rate increases. As described above, by applying a negative voltage to the charge permeation control unit 9a, electrons e are attached to the surface of the oxide layer, and more positively charged oxygen ions are generated by the action of the electric field by the attached electrons e. It is thought that it is because many are drawn.

  Then, if there is a distribution (density difference in pattern form) in the pitch dimension of the pattern (uneven portion) formed on the surface of the workpiece W (for example, a silicon substrate), a processing layer (for example, The thickness of the oxide layer becomes non-uniform, but the difference in thickness increases as the oxidation rate increases.

In this case, when it is necessary to form a treatment layer having a thickness corresponding to the difference in pitch dimension (the treatment layer having a longer pitch dimension needs to be thicker and the treatment layer having a shorter pitch dimension needs to be thinner). In such a case, the applied voltage can be controlled without switching the polarity of the voltage applied to the charge transmission control unit 9a.
On the other hand, when it is necessary to form a treatment layer having a uniform thickness, the polarity of the voltage applied to the charge transmission control unit 9a may be switched and the applied voltage may be controlled.

  For example, in the above-described case, if the polarity of the voltage applied to the charge transmission control unit 9a is switched to apply a positive voltage, the charge transmission control unit 9a captures negatively charged charged particles and electrons e. be able to. Therefore, the amount of electrons e flying on the surface of the object to be processed can be extremely reduced, so that the amount of electrons adhering to the surface of the object to be processed can be extremely reduced. As a result, it is possible to prevent the charged particles that are positively charged from being attracted by the action of the electric field by the attached electrons e.

  In this case, since a positive voltage is applied to the charge transmission control unit 9a, positively charged charged particles receive a repulsive force, and thus cannot pass through the charge transmission control unit 9a, and charge is generated from the generation position of the plasma P. It is confined in the space up to the position of the transmission control unit 9a. Therefore, the amount of positively charged charged particles flying on the surface of the object to be processed is small, and the surface treatment is performed mainly with neutral active species that are not significantly affected by the charge permeation control unit 9a.

  And when a neutral active species becomes the main subject of a process, since it becomes a chemical process, an isotropic process will be performed. In addition, since the influence of the attached electrons e can be suppressed, a treatment layer having a uniform thickness can be obtained even when there is a distribution (a density difference in the pattern form) of the pattern (uneven portion). Can do.

  On the other hand, when there is no pattern (uneven portion) itself, or when the pitch dimension of the pattern (uneven portion) is uniform, as described above, a negative voltage is applied to the charge transmission control portion 9a to the surface of the workpiece. The surface treatment speed can be increased by increasing the amount of attached electrons and utilizing the action of the electric field by the attached electrons e.

  Further, even when there is a distribution (density difference in pattern form) in the pitch dimension of the pattern (uneven portion), if a high negative voltage is applied to the charge transmission control unit 9a, the object to be processed The electrons e can be uniformly attached to the surface of the film.

This is not necessarily clear, but by accelerating the flying electrons e, the electric field caused by the electrons e adhering to the vicinity of the opening of the pattern (uneven portion) is broken, and the “valley bottom” portion of the pattern (uneven portion) is formed. This is also because the electron e can be attached.
For this reason, the negative voltage applied to the charge transmission control unit 9a may be set to a value that can accelerate the flying electron e to a speed at which the electric field caused by the electron e attached near the opening of the pattern (uneven portion) is broken.

  In this case, the surface treatment speed can be increased by increasing the amount of electrons attached to the surface of the object to be processed and utilizing the action of the electric field by the attached electrons e.

  The negative voltage applied to the charge permeation control unit 9a (the voltage that can accelerate the flying electron e to the speed at which the electric field caused by the electron e attached near the opening of the pattern (uneven portion) is broken) is the surface of the object to be processed. Influenced by material and pitch dimensions. For this reason, it is preferable to select the case where the positive voltage is applied or the case where a high negative voltage is applied, depending on conditions such as the material of the surface of the workpiece and the pitch dimension.

  Further, the above is seen from the amount of electrons e adhering to the surface of the workpiece. When a positive voltage is applied to the charge transmission control unit 9a, the electrons e are captured by the charge transmission control unit 9a, so that the amount of the electrons e adhering to the surface of the object to be processed decreases. If the voltage is increased, the amount of attached electrons e can be reduced. When a positive voltage is applied, the isotropic treatment with neutral active species becomes easier as the amount of adhering electrons e decreases.

  On the other hand, when a negative voltage is applied to the charge transmission control unit 9a, the electrons e receive repulsion by the charge transmission control unit 9a, but some of the electrons e pass through the charge transmission control unit 9a and adhere to the surface of the object to be processed. To do. In this case, if there is a distribution in the pitch dimension of the pattern (uneven portion) (a density difference in the form of the pattern), the adhesion of electrons e becomes non-uniform. However, when a high negative voltage is applied, the electrons e are accelerated, and the electric field due to the electrons e adhering to the vicinity of the opening of the pattern (uneven portion) can be broken. Can be attached to. In addition, when applying a negative voltage, the process using the electric field by the attached electron e becomes easy to be performed, so that the quantity of the attached electron e increases.

  That is, the amount of electrons e adhering to the surface of the object to be processed is controlled appropriately by the action of the electric field by the charge transmission control unit 9a formed above the surface of the object to be processed. Will be able to.

Next, the surface treatment method according to the embodiment of the present invention will be exemplified together with the operation of the plasma processing apparatus.
First, the workpiece W is placed on the stage 5 with the surface to be processed facing upward. Next, after the processing chamber 2 is depressurized by an exhaust means (not shown), the reaction gas G is introduced into the plasma generation space 7 through the gas supply pipe 11.

  On the other hand, the microwave M oscillated from a microwave oscillator (not shown) is guided through the microwave waveguide 4 and introduced into the transmission window 3 from the slot antenna 12. The introduced microwave M propagates through the surface of the transmission window 3 and is emitted toward the plasma generation space 7. The plasma of the reactive gas G is formed by the energy of the microwave M thus radiated.

  When the electron density in the plasma P thus generated becomes higher than the density (cutoff density) that can shield the microwave M transmitted through the transmission window 3, the microwave M is generated from the lower surface of the transmission window 3. It is reflected until it enters the space 7 by a certain distance (skin depth), and a microwave standing wave is formed between the reflection surface of the microwave M and the lower surface of the slot antenna 12. become.

  Then, the reflection surface of the microwave M becomes a plasma excitation surface, and a stable plasma P is excited on this plasma excitation surface. In the stable plasma P excited on the plasma excitation surface, ions and electrons collide with molecules of the reaction gas G to generate charged particles, neutral active species, and the like. These plasma products descend in the plasma generation space 7 defined by the shield 8 and reach the charge transmission control unit 9 a of the processing control means 9.

A positive or negative voltage is applied to the charge permeation control unit 9a as necessary to prevent the electron e from adhering to the surface of the workpiece W, or to apply the electron e to the surface of the workpiece W. The process which increased the surface treatment speed by making it adhere is performed.
That is, the processing of the workpiece W is performed by controlling the amount of electrons attached to the surface of the workpiece W by the action of the electric field formed above the surface of the workpiece W.

  Thereafter, the surface treatment can be performed by repeating the above-described procedure if necessary.

Here, the treatment conditions for the surface treatment are exemplified.
For example, when oxidizing the surface of a silicon substrate having a pattern formed on the surface, the reactive gas G is oxygen gas or oxygen gas and an inert gas (for example, He, Ar, Kr, Xe, etc.). The temperature of the silicon substrate can be about 400 ° C. to 600 ° C., the processing time can be about 10 minutes, and the processing pressure can be about several hundred Pa.

When the pitch dimension of the pattern (uneven portion) has a distribution (density difference in pattern form), an oxide film having a uniform thickness is formed by applying a positive voltage to the charge transmission control portion 9a. Obtainable. Note that a high negative voltage can be applied to the charge transmission control unit 9a.
On the other hand, when the pattern pitch dimension is uniform, by applying a negative voltage to the charge permeation control unit 9a, a process with a high oxidation rate using the electric field of the attached electrons e can be performed.

  Here, when a silicon substrate having a distribution (density difference in pattern form) in the pitch dimension of the pattern (uneven portion) was subjected to an oxidation process using a plasma processing apparatus not provided with the processing control means 9, the pitch dimension The thickness of the treatment layer in the short portion / the thickness of the treatment layer in the portion with the long pitch dimension = 0.72.

On the other hand, when the plasma treatment apparatus 1 according to the present embodiment is used and a high negative voltage (−100 V) is applied to the charge permeation control unit 9a to oxidize the same object, the pitch dimension is short. It was confirmed that the thickness of the portion of the treatment layer / the thickness of the treatment layer of the portion having a long pitch dimension = 1.00, and the uniformity can be greatly improved. This is because, as described above, when a high negative voltage is applied, the electrons e are accelerated, and the electric field due to the electrons e attached in the vicinity of the opening of the pattern (uneven portion) can be broken. This is considered to be because the electrons e can be uniformly attached to the surface.
Further, when a high positive voltage (+100 V) is applied to the charge permeation control unit 9a to oxidize the same workpiece, the treatment layer thickness / pitch dimension of the portion with a short pitch dimension is processed. The thickness of the layer was 0.86, and it was confirmed that the uniformity could be improved also in this case. This is presumably because the amount of adhering electrons e can be reduced by applying a high positive voltage as described above.
For convenience of explanation, the oxidation treatment of the silicon substrate (semiconductor device manufacturing method) is exemplified as the surface treatment method according to the embodiment of the present invention, but the present invention is not limited to this. For example, it can be applied to the production of liquid crystal display devices, the production of fuel cells, the production of solar cells, and other various electronic components and precision components. Besides oxidation treatment, for example, nitriding treatment, It can also be applied to oxynitriding.

  Moreover, although what used surface wave plasma was illustrated as the plasma processing apparatus 1, it is not necessarily limited to this. For example, a parallel plate type plasma processing apparatus, an inductively coupled plasma processing apparatus, or the like may be provided with the processing control means 9. However, in the case of the oxidation treatment of the silicon substrate described above, it is preferable that high density plasma can be generated.

The embodiment of the present invention has been described above. However, the present invention is not limited to these descriptions.
As long as the features of the present invention are provided, those skilled in the art appropriately modified the design of the above-described embodiments are also included in the scope of the present invention.
For example, the shape, size, material, arrangement, and the like of each element included in the plasma processing apparatus 1 are not limited to those illustrated, but can be changed as appropriate.
Moreover, each element with which each embodiment mentioned above is combined can be combined as much as possible, and what combined these is also included in the scope of the present invention as long as the characteristics of the present invention are included.

It is a schematic cross section for illustrating the plasma processing apparatus concerning an embodiment of the invention. It is a schematic graph for demonstrating the relationship between the voltage applied to a charge permeation | transmission control part, and the electric current which flows into the to-be-processed object surface. It is a schematic graph for demonstrating the oxidation process which concerns on a comparative example. It is a schematic diagram for illustrating the influence which the density difference of a pattern has on the oxidation rate. It is a schematic graph for demonstrating the case where the polarity of the voltage applied to an electric charge transmission control part is switched.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus, 2 Processing chamber, 3 Transmission window, 4 Microwave waveguide, 5 Stage, 6 Processing space, 7 Plasma generation space, 8 Shielding body, 9 Processing control means, 9a Charge transmission control part, 9b Power supply part, 10 exhaust pipe, 11 gas supply pipe, 12 slot antenna, M microwave, P plasma, W

Claims (7)

Depressurize the processing chamber below atmospheric pressure,
Introducing a reaction gas into the processing chamber;
Generating a plasma in the processing chamber;
The reaction gas is decomposed and activated by the plasma,
Adjusting the electric field of a charge permeation control unit provided between the plasma and the object to be processed while controlling the amount of charge on the surface of the object to be processed; A characteristic surface treatment method.   The surface treatment method according to claim 1, wherein an uneven portion having a relatively short pitch portion and a long pitch portion is provided on the surface of the workpiece. When the surface of the object to be processed has flat or uniform unevenness, a negative voltage is applied to the charge transmission control unit,
The positive voltage is applied to the charge transmission control unit when unevenness having a relatively short pitch portion and a long pitch portion is formed on the surface of the workpiece. 2. The surface treatment method according to 1.   The surface treatment method according to any one of claims 1 to 3, wherein the charge transmission control unit is a net-like body made of a conductor.   The surface treatment method according to claim 1, wherein the reaction gas is a gas containing oxygen. A processing chamber capable of maintaining an atmosphere depressurized from atmospheric pressure;
Means for generating plasma in a plasma generation space in the processing chamber;
Means for introducing a reactive gas into the plasma generation space;
A stage provided below the plasma generation space and on which a workpiece is placed;
A process control means comprising: a charge transmission control unit provided so as to cover the upper surface of the stage; and a power supply unit capable of controlling the voltage and polarity in the charge transmission control unit;
A plasma processing apparatus comprising:   The plasma processing according to claim 6, wherein the processing control unit is capable of controlling an amount of electrons on a surface of the object to be processed by controlling a voltage and a polarity of the transmission control unit. apparatus.