JP2002203836A - Plasma treatment method and plasma treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treatment method capable of easily performing uniform plasma treatment and performing the plasma treatment of a thick object to be treated. SOLUTION: Electrodes 1, 2 are arranged on the upstream side and the downstream side of gas flow, the electrode 2 of the upstream side is opposed to the electrode 1 of the downstream side, and a discharge space 3 is formed between the electrode 2 of the upstream side and the electrode 1 of the downstream side. Gas is supplied to the discharge space 3, and discharge is performed in the gas under pressure in the neighborhood of atmospheric pressure to generate plasma 4 by applying alternating high voltage between the electrode 2 of the upstream side and the electrode 1 of the downstream side. The plasma 4 generated in the discharge space 3 is flowed out to the downstream side rather than the electrode 1 of the downstream side, and the plasma 4 is supplied to an object to be treated 5 by arranging the object to be treated 5 to the downstream side rather than the electrode 1 of the downstream side. The object to be treated 5 cannot be interposed between the opposite electrodes 1, 2. Even when the thick object to be treated 5 exists rather than the interval between the electrodes 1, 2, the plasma 4 can be supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning of foreign substances such as organic substances present on the surface of an object to be processed, peeling of resist, improvement of adhesion of an organic film, reduction of metal oxide,
The present invention relates to a plasma processing apparatus and a plasma processing method for performing plasma processing such as film formation, surface modification, and surface cleaning of a liquid crystal glass substrate, and particularly relates to a surface cleaning of an electronic component that requires precise bonding. It is applied to.

[0002]

2. Description of the Related Art Conventionally, plasma generated on a surface of an object to be processed is supplied by supplying a plasma generated under a pressure near the atmospheric pressure to the surface of the object to be brought into contact with the surface of the object. An example of such a plasma processing apparatus is disclosed in Japanese Patent Application Laid-Open No. 4-168281.

In the plasma processing apparatus described in this publication, a discharge space is formed between electrodes by arranging a pair of electrodes so as to face each other, and at least one of the pair of electrodes is formed of a conductive mesh electrode. A gas is supplied from the outside of the conductive mesh electrode toward the discharge space and a high voltage is applied between the pair of electrodes to discharge in the gas in the discharge space to generate plasma, and the workpiece is placed in the discharge space. By arranging, plasma is supplied to the surface of the object to be processed to perform plasma processing. In this plasma processing apparatus, a conductive mesh electrode is used as an electrode, and gas is supplied to the discharge space by passing the conductive mesh electrode from outside the conductive mesh electrode. This makes it possible to achieve uniform film formation by plasma processing.

[0004]

However, in the above-described plasma processing apparatus, since the plasma processing is performed by arranging the workpiece in a discharge space formed between a pair of electrodes, the workpiece is interposed between the electrodes. As a result, there is a problem that the discharge state changes depending on the presence or absence and the material of the object to be processed, and it is difficult to perform uniform plasma processing. Further, the pair of electrodes is arranged at a predetermined interval for stabilizing the discharge and the like. For this reason, an object to be processed that is thicker than the interval between the electrodes cannot be arranged in the discharge space. There is a problem that the plasma processing of the object cannot be performed. Also, a substrate on which a semiconductor (semiconductor chip) is mounted, for example,
BGA (Ball Grid Array) and CSP (Chip Size Packa)
In the case where plasma processing is performed on a semiconductor mounting substrate such as ge) or a liquid crystal substrate on which a TFT is formed as a processing object, if these processing objects are arranged in the plasma, the semiconductor may be damaged by the plasma charged particles, and in some cases, Has the problem that the semiconductor is destroyed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is easy to perform uniform plasma processing, and it is possible to perform plasma processing on a thick workpiece, and to prevent semiconductor destruction. It is an object of the present invention to provide a plasma processing method and a plasma processing apparatus capable of performing such a method.

[0006]

According to a first aspect of the present invention, there is provided a plasma processing method comprising: arranging electrodes 1 and 2 on an upstream side and a downstream side of a gas flow; The discharge space 3 is formed between the electrode 2 on the upstream side and the electrode 1 on the downstream side, and gas is supplied to the discharge space 3 and the alternating high voltage is applied to the electrode 2 on the upstream side and the electrode 1 on the downstream side. Between the discharge space 3 and the discharge space 3
Supplying the plasma 4 to the processing object 5 by causing the plasma 4 generated in the above to flow out of the downstream electrode 1 and arranging the processing object 5 downstream of the downstream electrode 1. It is characterized by the following.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the discharge space is formed by forming the downstream electrode 1 from a porous material and passing the downstream electrode 1 therethrough. It is characterized in that the plasma 4 generated in 3 is discharged to the downstream side of the electrode 1 on the downstream side.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the porous material is a mesh or a punching plate.

A plasma processing method according to a fourth aspect of the present invention is characterized in that, in addition to the configuration of the second or third aspect, the thickness of the porous material is 10 mm or less.

According to a fifth aspect of the present invention, in addition to the structure of the first aspect, a plurality of downstream electrodes 1 are arranged and passed between adjacent downstream electrodes 1. It is characterized in that the plasma 4 generated in the discharge space 3 is caused to flow downstream of the downstream electrode 1.

A plasma processing method according to a sixth aspect of the present invention is characterized in that, in addition to the configuration of the fifth aspect, the distance between adjacent electrodes 1 is set to 2 mm or less.

A plasma processing method according to a seventh aspect of the present invention is characterized in that, in addition to the configuration of the fifth or sixth aspect, the downstream electrode 1 has a flat cylindrical shape or a cylindrical shape.

The plasma processing method according to claim 8 of the present invention is characterized in that, in addition to the structure of claims 1 to 7, the downstream electrode 1 is grounded.

A plasma processing method according to a ninth aspect of the present invention is characterized in that, in addition to the constitutions of the first to eighth aspects, the alternating high voltage is a pulse voltage.

A plasma processing method according to a tenth aspect of the present invention is characterized in that, in addition to the constitutions of the first to ninth aspects, the electrodes 1 and 2 on which the ceramic or glassy coating 7 is formed are used. It is.

According to the plasma processing method of claim 11 of the present invention, in addition to the constitution of claim 10, the withstand voltage of the coating film 7 is 2 or less.
５０50 kV / mm.

According to a twelfth aspect of the present invention, there is provided a plasma processing method according to the tenth or eleventh aspect, further comprising using the electrodes 1 and 2 on which a coating is formed by applying a ceramic material by ceramic spraying. It is a feature.

According to a thirteenth aspect of the present invention, there is provided a plasma processing method according to the tenth or eleventh aspect, further comprising using the electrodes 1 and 2 formed by coating a vitreous material by thermal fusion to form a coating 7. It is characterized by the following.

A plasma processing method according to a fourteenth aspect of the present invention is characterized in that, in addition to any one of the first to thirteenth aspects, the electrodes 1 and 2 are cooled by a refrigerant.

A plasma processing method according to a fifteenth aspect of the present invention is characterized in that, in addition to any one of the first to fourteenth aspects, the fan 8 generates a gas flow toward the discharge space 3. is there.

A plasma processing method according to a sixteenth aspect of the present invention, in addition to the structure of any one of the first to fifteenth aspects, further comprises a processing chamber 9 formed in substantially the same gas atmosphere as the discharge space 3.
It is characterized in that the object 5 is subjected to plasma processing.

According to a seventeenth aspect of the present invention, in addition to the configuration of the sixteenth aspect, the plasma processing method further comprises the steps of:
It is characterized by being formed so as to be openable and closable.

A plasma processing method according to an eighteenth aspect of the present invention is characterized in that, in addition to any one of the first to seventeenth aspects, the plasma processing is performed while continuously transporting a large number of workpieces 5. It is assumed that.

A plasma processing apparatus according to a nineteenth aspect of the present invention is characterized in that the processing target 5 is subjected to plasma processing by the method according to any one of the first to eighteenth aspects.

[0025]

Embodiments of the present invention will be described below.

FIG. 1 shows a plasma processing apparatus for performing plasma processing in an in-line system. The chamber 10 is formed in a box shape, and the joint portion is provided with a packing such as an O-ring so as to have high airtightness. The interior of the chamber 10 is partitioned into three chambers, an introduction chamber 11, a processing chamber 9, and a discharge chamber 12, and a partition wall 15 separating the introduction chamber 11 and the processing chamber 9 opens to the introduction chamber 11 and the processing chamber 9. An inlet 13 is formed, and the processing chamber 9 and the outlet chamber 12 are formed.
The outlet 16 that opens to the processing chamber 9 and the outlet chamber 12 is formed in a partition wall 16 that separates the chambers. The chamber 10
The outside wall of the chamber 10 and the introduction chamber 1
An inlet 18 opening to the first chamber 1 is formed, and an outlet 20 opening to the outside of the chamber 10 and the outlet chamber 12 is formed in the other side wall 19 of the chamber 10. Further, a gate (door) 6 is provided outside the side walls 17 and 19. The gate 6 is formed so as to be vertically driven by air pressure or the like adjusted by a valve or the like. The inlet 18 or the outlet 20 is opened by moving the gate 6 upward, and the inlet is opened by moving the gate 6 downward. 18 or the outlet 20 is closed.

A gas for plasma generation is introduced into the processing chamber 9 as shown by an arrow, and the inside of the processing chamber 9 is filled with this gas. Is introduced so that the inside of the introduction chamber 11 and the inside of the discharge chamber 12 are filled with this gas. Therefore, the provision of the introduction chamber 11 and the derivation chamber 12 makes it difficult for the gas in the processing chamber 9 to flow out of the inlet 18 and the outlet 20, thereby preventing the gas concentration in the processing chamber 9 from decreasing. is there. That is, when the introduction chamber 11 and the derivation chamber 12 are not provided, each time the object 5 is introduced into or deducted from the chamber 10, the entrance 1 is set.
When the outlet 8 and the outlet 20 are opened, a large amount of gas in the processing chamber 9 flows out of the chamber 10 to lower the gas concentration in the processing chamber 9. , The introduction chamber 11 and the extraction chamber 1
2 serves as a buffer chamber to prevent the gas from directly flowing out of the processing chamber 9. Therefore, the gas concentration in the processing chamber 9 can be kept substantially constant, and The plasma processing can be performed uniformly. As shown by arrows, the introduction chamber 11 and the derivation chamber 12
The gas introduced from its upper surface is drawn out from the lower surfaces of the inlet chamber 11 and the outlet chamber 12 as shown by arrows.

The chamber 10 can be formed of a synthetic resin such as an acrylic resin or a metal such as stainless steel. Preferably, the inner surface of the chamber 10 is coated with an insulator. Examples of the insulator include a vitreous material and a ceramic material such as quartz, alumina, and partially stabilized zirconium yttria. further,
Alumina (Al ₂ O ₃ ), titanium oxide (TiO _{2 with} titania
₂ ), SiO ₂ , AlN, Si ₃ N, SiC, DLC (diamond-like carbon film), barium titanate, PZT
(Lead zirconate titanate) and the like. Alternatively, magnesia (MgO) alone or an insulating material containing magnesia can be used. As a coating method, a plate-shaped insulator is adhered to and adhered to the inner surface of the chamber 10, or powder such as alumina, barium titanate, titanium oxide, or PZT is dispersed in plasma to form an inner surface of the chamber 10. Spraying, and dispersing an inorganic powder such as silica, tin oxide, titania, zirconia, or alumina with a solvent or the like, and spraying the inner surface of the chamber 10 with a spray or the like to coat the inner surface of the chamber 10 at 600 ° C.
A so-called enamel coating method of melting at the above temperature, a method of forming a glassy film by a sol-gel method, and the like can be employed. Further, the inner surface of the chamber 10 can be coated with an insulator by a vapor deposition method (CVD) or a physical vapor deposition method (PVD).

By coating the inner surface of the chamber 10 with an insulator as described above, it is possible to prevent discharge from occurring between the electrodes 1 and 2 and the inner surface of the chamber 10, and to prevent discharge between the electrodes 1 and 2. Efficiency can be increased, and plasma can be efficiently generated. The outer surface of the chamber 10 may be coated with an insulating material.

In the processing chamber 9 of the chamber 10, electrodes 1, 2 and a fan 8 are provided. The electrodes 1 and 2 are formed of a conductive metal material.
It can be formed of copper, aluminum, brass, stainless steel having high corrosion resistance (such as SUS304), or the like. One electrode 1 is formed of a porous material having a large number of through holes 21 penetrating in the thickness direction, whereby the electrode 1 is formed so as to have air permeability in the thickness direction.
As such a porous material, for example, a mesh (wire mesh) or a punching plate in which a large number of pores (through holes 21) are formed in a flat plate can be used. It is preferable that they are formed substantially uniformly (substantially at equal intervals) over the whole. Further, the thickness of the porous material is preferably set to 10 mm or less. When the thickness of the porous material is larger than 10 mm, the thickness of the electrode 1 is larger than 10 mm, and the time for the plasma 4 generated in the discharge space 3 to pass through the electrode 1 becomes longer, and the radicals in the plasma 4 have high activity. There is a possibility that the workpiece 5 may not be effectively reached as it is. The smaller the thickness of the electrode 1 is, the more difficult the above-mentioned problem is to occur. Therefore, the thickness of the porous material is preferably smaller. The lower limit of the thickness of the porous material is not particularly set. It is preferable that it is above.

The other electrode 2 can be formed in a cylindrical shape as shown in FIG. 1 and FIG. 2 (a), but as shown in FIG. ) May be formed. Further, as shown in FIG. 2, the inside of the electrode 2 is formed as a flow path 23 through which a refrigerant can pass. When the electrode 2 is formed in a flat cylindrical shape, it is preferable that the outer corner portion of the electrode 2 is formed on an R surface (curved surface) rather than being angular.
If the outer corner of the electrode 2 is angular, the electric field tends to be concentrated in the discharge space starting from the corner, whereby a streamer is generated, making it difficult to perform uniform plasma processing. Therefore, by making the outer corner of the electrode 2 an R-plane, the concentration of the electric field is prevented from occurring in the discharge space, and the electric field is made uniform. It is possible to prevent breakage and to further improve the uniformity of the plasma processing.

As the refrigerant, ion exchange water or pure water can be used. By using ion-exchange water or pure water, no impurities are contained in the refrigerant, and the electrode 2
Is hardly corroded by the refrigerant. Further, the refrigerant is preferably a liquid having antifreeze at 0 ° C., and having electrical insulation and nonflammability and chemical stability. For example, the electrical insulation performance has a withstand voltage at 0.1 mm intervals. 10k
It is preferably at least V. The reason why the refrigerant having the insulating property in this range is used is to prevent electric leakage from the electrode 2 to which a high voltage is applied. Examples of the refrigerant having such properties include perfluorocarbon, hydrofluoroether and the like, and may be a mixed liquid obtained by adding 5 to 60% by weight of ethylene glycol to pure water. Further, the refrigerant may be air.

The electrode 2 is cooled by passing a coolant through the flow path 23 during plasma generation (during discharge), whereby the electrode 2 is cooled near the atmospheric pressure (93.3 to 103.3).
Even if the plasma 4 is generated at a high frequency and a high voltage under a pressure of 6.7 kPa (700 to 800 Torr), a rise in the temperature of the electrode 2 can be suppressed, and the temperature of the plasma 4 (gas temperature) is not increased. Thus, thermal damage to the processing object 5 can be reduced. Also, electrode 1,
Local heating of the discharge space 3 formed between the two can be prevented, a more uniform glow-like discharge is generated, and generation of a streamer discharge is suppressed, and damage to the workpiece 5 due to the streamer discharge is reduced. Is what you can do.
The electrode 1 may be provided with a flow path through which a coolant flows, and may be cooled by the coolant.

A ceramic or vitreous coating 7 can be formed on the surfaces (outer surfaces) of the electrodes 1 and 2 described above. As a method of forming such a coating 7, a method in which a plate-like or tubular insulator is adhered to and adhered to the surfaces of the electrodes 1 and 2, and a powder such as alumina, barium titanate, titanium oxide, and PZT are used. (Ceramic material) is dispersed in plasma and sprayed onto the surfaces of the electrodes 1 and 2 (plasma spraying method), and inorganic powders such as silica, tin oxide, titania, zirconia, and alumina (glassy) Is dispersed by a solvent or the like,
It is possible to employ a so-called enamel coating method in which the surfaces of the electrodes 1 and 2 are sprayed and coated with a spray or the like, and then melted at a temperature of 600 ° C. or more and thermally fused, and a method of forming a glassy film by a sol-gel method. it can. Further, the surfaces of the electrodes 1 and 2 can be coated with an insulator by a vapor deposition method (CVD) or a physical vapor deposition method (PVD).

In forming the coating 7, specifically, a glaze made of an inorganic powder (glassy material) such as silica, tin oxide, titania, zirconia, or alumina is sprayed on the surfaces of the electrodes 1 and 2. It is supplied by dipping or dipping to form a film of the dispersion on the surfaces of the electrodes 1 and 2 and then heat-treated at a temperature of 480 to 1000 ° C. for 1 to 15 minutes. Can be formed by heat-sealing an inorganic powder to the surface of the substrate.

By providing the ceramic or vitreous coating 7 on the surfaces of the electrodes 1 and 2 as described above, it is possible to prevent the plasma 4 and the gas for plasma generation from coming into direct contact with the electrodes 1 and 2. It is possible to protect the electrodes 1 and 2 from the sputtering action of the plasma 4 and the corrosive action of gas, to reduce the deterioration of the electrodes 1 and 2, and to prevent impurities from being generated from the electrodes 1 and 2. Thus, the object 5 can be prevented from being contaminated by impurities even when used for a long time.

The withstand voltage of the coating 7 formed on the surfaces of the electrodes 1 and 2 is preferably 2 to 50 kV / mm. If the withstand voltage of the coating 7 is less than 2 kV / mm, the coating 7 may not be able to withstand the high voltage applied between the voltages 1 and 2 and may be damaged. If the withstand voltage of the coating 7 is more than 50 kV / mm. ,
Inevitably, the thickness of the coating 7 must be increased, and the high voltage applied to the discharge space 3 may be relatively reduced.
The thickness of the coating 7 can be appropriately adjusted depending on the desired withstand voltage and composition, but can be, for example, 0.1 to 3 mm.

An end of the electrode 1 is fixed to an insulating holder 22 provided on the processing chamber 9 side of the partition walls 15 and 16, whereby the electrode 1 has a through hole 21 penetrating vertically. The partition wall 15 of the processing chamber 9 is held substantially horizontally
It is arranged over the entire length between the sixteen. Above the electrode 1, a plurality of electrodes 2 are disposed substantially horizontally. The plurality of electrodes 2 move in the direction of transport of the workpiece 5 (FIG. 1).
(Indicated by arrows in FIG. 2), and a gap is provided as a gas introduction part 30 between the adjacent electrodes 2. Each electrode 2 is disposed so that its longitudinal direction is orthogonal to the direction of transport of the workpiece 5, and each electrode 2 is fixed to an insulating fixture 24 provided on the inner surface of the processing chamber 9. I have. By arranging the electrodes 1 and 2 vertically facing each other, a discharge space 3 is formed between the vertically opposed electrodes 1 and 2. Incidentally, the upper electrode 2 may be formed of a porous material in the same manner as the lower electrode 1.

The upper and lower distances (gaps) between the electrodes 1 and 2 are as follows:
It is preferable to set it to 1 to 20 mm. If the distance between the electrodes 1 and 2 is less than 1 mm, a short circuit may occur between the electrodes 1 and 2 and the discharge may not occur in the discharge space 3, and the discharge space 3 is narrowed to efficiently generate plasma. Can be difficult to do. On the other hand, if the distance between the electrodes 1 and 2 exceeds 20 mm, it is difficult to generate a discharge in the discharge space 3 and it may be difficult to efficiently generate plasma.

It is preferable that the distance between the adjacent upper electrodes 2, that is, the dimension of the gas introduction section 30 in the direction parallel to the direction of transport of the workpiece 5 is set to 2 mm or less. If this interval is wider than 2 mm, the flow rate of the gas introduced into the discharge space 3 decreases, and as a result, the flow rate of the plasma 4 flowing out of the discharge space 3 downstream of the lower electrode 1 also decreases. And the plasma processing performance may be reduced. The interval between the adjacent upper electrodes 2 is set to 0.1.
It is preferable that the distance is 1 mm or more. If the distance is smaller than this, it becomes difficult to supply a sufficient amount of gas to the discharge space 3, and there is a possibility that the plasma 4 cannot be generated efficiently.

A plurality of fans 8 are provided in the processing chamber 9 above the upper electrode 2. When the fan 8 is operated, as shown by an arrow in FIG.
Can generate a gas flow toward the discharge space 3 from above. As shown by the arrows, the gas for plasma generation is supplied from the upper surface of the processing chamber 9, but without the fan 8, the gas is difficult to be introduced into the discharge space 3 through the gap between the adjacent electrodes 2. Therefore, in the present invention, the gas is forcibly sent to the discharge space 3 by providing the fan 8 above the upper electrode 2, whereby the gas is reliably introduced into the discharge space 3. And the gas is blown to the electrode 2 to cool the electrode 2. In addition, fan 8
1 can generate a gas flow (flow of the plasma 4) from the discharge space 3 to the lower side of the lower electrode 1, as indicated by the arrow in FIG. A gas flow (flow of the plasma 4) from the space 3 toward the processing object 5 can be generated, whereby the flow rate of the plasma 4 can be increased, and the flow rate of the lower electrode 1 can be increased. The pressure at which the plasma 4 is sprayed onto the workpiece 5 disposed below can be increased, the processing speed of the plasma processing can be increased, and the effect of the plasma processing can be enhanced.

Since the gas flows in one direction from the top to the bottom as described above, the upper electrode 2 is formed as the upstream electrode 2 disposed on the upstream side of the gas flow, and the lower electrode 2 is formed. The electrode 1 is formed as a downstream electrode 1 arranged downstream of the gas flow.

The upstream electrode 2 is electrically connected to a power supply 25. The power supply 25 is capable of applying a voltage required for continuously generating the plasma 4 in the discharge space 3 between the electrodes 1 and 2, and may use a power supply that generates an alternating high voltage. . Further, the power supply 25 may generate a voltage waveform (for example, a sine wave) having no or almost no pause time (time during which the voltage is constant and in a steady state). It is preferable to use a power supply 25 that generates a waveform, that is, a pulse voltage, so that a pulse voltage can be applied between the electrodes 1 and 2, and the discharge can be stabilized more than applying a voltage having no pause. You can do it. The voltage required to continuously generate the plasma 4 in the discharge space 3 varies depending on the size of the discharge space 3 and the composition of the gas for plasma generation, and may be appropriately set.
５5 kV can be set.

As described above, the upstream electrode 2 is electrically connected to the power supply 25, while the downstream electrode 1 is grounded. As described above, by applying a high voltage to the upstream electrode 2 arranged at a position far from the object 5 and grounding the downstream electrode 1 arranged at a position close to the object 5, An abnormal discharge from the electrodes 1 and 2 to the object 5 can be prevented, and the object 5 can be prevented from being damaged by the abnormal discharge. Even the processed object 5 is particularly effective because it can be subjected to plasma processing so as not to damage the semiconductor.

The power supply 25 has a frequency of 1 kHz to 20
It is preferable to use a device that generates a high voltage of 0 MHz and applies it between the electrodes 1 and 2. If the frequency of the high voltage applied between the electrodes 1 and 2 is less than 1 kHz, the discharge in the discharge space 3 cannot be stabilized, and the plasma processing may not be performed efficiently. ,
If the frequency of the high voltage applied between the two exceeds 200 MHz, the temperature of the plasma 4 in the discharge space 3 rises significantly, and the life of the electrodes 1 and 2 may be shortened.
The plasma processing apparatus may be complicated and large.

The density of the electric power applied to the discharge space 3 is 20 to 3500 W / cm ³ , preferably 100 to 3500 W / cm ³ .
It is preferable to set it to 500 W / cm ³ . Discharge space 3
If the density of the applied power applied to the discharge space 3 is less than 20 W / cm ³ , the plasma 4 cannot be sufficiently generated.
If it exceeds 500 W / cm ³ , a stable discharge may not be obtained, and in any case, the plasma processing may not be performed stably. Note that the density (W / cm ³ ) of the applied power is defined by (applied power supplied to the discharge space 3 from the power supply 25 / volume of the discharge space 3).

The roller 2 is provided inside and outside the chamber 10.
6 are provided. The upper end of the roller 26 is the entrance 18
The roller 26 is disposed substantially horizontally long so as to be substantially the same height as the outlet 20.
Are arranged so as to be arranged in parallel with the transfer direction of. Therefore, in the processing chamber 9, the plurality of rollers 26
Are arranged so as to be arranged below the electrode 1. The roller 26 is rotatably driven by a driving means such as a motor.
The workpiece 5 can be conveyed in the direction of the arrow by the rotation of the roller 26 by placing the sheet. The roller 26 is preferably formed of a synthetic resin having high heat resistance such as polytetrafluoroethylene (trade name: Teflon).

As a gas for generating plasma, an inert gas (rare gas) or a mixed gas of an inert gas and a reactive gas can be used.
The cleaning effect of the organic substance existing on the surface of the substrate and the reduction effect of the metal oxide can be realized. As the inert gas, helium, argon, neon, krypton, or the like can be used, but it is preferable to use argon or helium in consideration of discharge stability and economy. Further, the type of the reaction gas can be arbitrarily selected depending on the contents of the plasma processing. For example, oxygen, air, CO ₂ , N ₂ O are used when cleaning the organic substance existing on the surface of the processing object 5, stripping the resist, etching the organic film, cleaning the surface of the LCD, cleaning the surface of the glass plate, and the like. It is preferable to use an oxidizing gas such as In addition, a fluorine-based gas such as CF ₄ can be appropriately used as a reaction gas. When etching silicon or the like, it is effective to use this fluorine-based gas. In the case of reducing a metal oxide, a reducing gas such as hydrogen or ammonia can be used. The addition amount of the reaction gas is preferably 10% by weight or less, more preferably 0.1 to 5% by weight, based on the total amount of the inert gas. If the addition amount of the reaction gas is less than 0.1% by weight, the treatment effect may be reduced, and if the addition amount of the reaction gas exceeds 10% by weight, the discharge may be unstable.

In performing the plasma processing of the workpiece 5 using the above-described plasma processing apparatus,
This is performed as follows. First, as shown by an arrow in FIG. 1, the above-described plasma generation gas is introduced into the processing chamber 9 from the upper surface of the processing chamber 9 of the chamber 10. The gas introduced into the processing chamber 9 as described above is introduced between the fan 8 and the electrode 2 on the upstream side, and flows downward by the blowing of the fan 8. The gas introduced into the discharge space 3 is supplied to the discharge space 3 through a gas introduction portion 30 formed between the adjacent upstream electrodes 2 as shown by arrows. Further, the inside of the processing chamber 9 is filled with the gas for plasma generation introduced into the discharge space 3.

On the other hand, the alternating high voltage as described above is applied between the opposing electrodes 1 and 2, thereby generating a discharge in the gas in the discharge space 3 at a pressure near the atmospheric pressure. The plasma 4 is generated almost uniformly over the entire discharge space 3. Then, the plasma 4 generated in the discharge space 3 is caused to flow downward by the blowing of the fan 8, and as a result, as shown by the arrow,
The plasma 4 generated in the step (1) is discharged to the downstream side (downward) of the downstream electrode 1 through the through hole 21 of the downstream electrode 1 formed of a porous material.

Next, the workpiece 5 is placed on the roller 26 provided on the inlet 18 side of the chamber 10 and the inlet 18 is
The gate 6 for closing is moved upward to open the entrance 18.
As a result, the workpiece 5 is conveyed by the rotating roller 26 and is introduced into the introduction chamber 11 through the entrance 18. Thereafter, the workpiece 5 introduced into the introduction chamber 11 is moved to the introduction chamber 1.
It is conveyed by rotating rollers 26 disposed in the inside 1 and the like, and is introduced into the processing chamber 9 from the introduction chamber 11 through the introduction port 13. Immediately after the workpiece 5 is introduced into the introduction chamber 11, the gate 6 on the entrance 18 side is moved downward so as to close the entrance 18, whereby the gas in the processing chamber 9 is released from the chamber 10. It is difficult to flow out of

The workpiece 5 introduced into the processing chamber 9 as described above is substantially horizontally moved from the inlet 13 to the outlet 14 by the rotating roller 26 in the processing chamber 9 as shown by the arrow. At this time, the workpiece 5 passes below the downstream electrode 1 formed of a porous material. Therefore, the workpiece 5 is disposed on the downstream side of the flow of the plasma 4 blown out from the through hole 21 of the electrode 1 while passing through the processing chamber 9. The plasma 4 is blown onto the (upper surface) and comes into contact with the upper surface, so that the surface of the workpiece 5 is subjected to plasma processing. Thereafter, the workpiece 5 subjected to the plasma processing is conveyed by the roller 26 that is driven to rotate, and is led out of the processing chamber 9 into the outlet chamber 12 through the outlet 14. Next, the gate 6 that closes the outlet 20 is moved upward to open the outlet 20, and the workpiece 5 is rotated by rollers 26 that are rotatably disposed inside the outlet chamber 12 and on the outlet 20 side of the chamber 10. Is transported, the workpiece 5 is led out of the chamber 10 through the outlet 20. In this way, the workpiece 5 can be subjected to the plasma processing. In addition, by sequentially supplying a large number of workpieces 5 into the chamber 10 in the same manner as described above, the plasma processing can be performed while continuously transporting the multiple workpieces 5.

In the present invention, the opposing electrodes 1, 2
Is formed as a discharge space 3, and plasma 4 generated by discharging in the discharge space 3 is supplied to the through-hole 2 of the electrode 1 made of a porous material.
1, the plasma is supplied from the discharge space 3 to the workpiece 5 disposed downstream of the flow of the plasma 4 to perform the plasma processing.
The workpiece 5 can be prevented from intervening between
Discharge instability due to the interposition of the workpiece 5 is eliminated, and uniform plasma 4 can be generated. This facilitates uniform plasma processing of the workpiece 5. . In addition, since the plasma processing is performed without introducing the workpiece 5 between the opposing electrodes 1 and 2,
Even if the workpiece 5 is thicker than the gap between the electrodes 1 and 2 without being affected by the gap between the electrodes 1 and 2 arranged at an optimum gap for the discharge for stabilization of the discharge, etc. And the plasma processing of the thick workpiece 5 can be performed.

Further, by forming the electrode 1 using a porous material such as a mesh in which a large number of through holes 21 are formed substantially uniformly (substantially at equal intervals) over the entire electrode 1, Through the through holes 21, the plasma 4 generated in the discharge space 3 can be made to flow out substantially uniformly from almost the entirety of the electrode 1, and the plasma 4 generated in the workpiece 5 can be made substantially uniform.
And a uniform plasma treatment can be performed. Further, the inside of the processing chamber 9 is filled with a plasma generating gas, and the plasma processing of the workpiece 5 is performed in a gas atmosphere substantially the same as the discharge space 3.
It is possible to prevent active species such as radicals contained in the plasma 4 blown out of the discharge space 3 from dying before reaching the object 5 to be treated. It can be supplied to the processing object 5 and supplied, and the effect of the plasma processing can be enhanced.

In the present invention, the plasma 4 generated in the discharge space 3 is caused to flow downstream of the downstream electrode 1 to supply the plasma 4 to the object 5 to be processed. The processing position of the workpiece 5 is separated, and the discharge space 3 exists immediately above the processing position, thereby preventing the charged particles in the plasma 4 from damaging the semiconductor. Can be
Even when the workpiece 5 on which a semiconductor (semiconductor element or semiconductor chip) is mounted is subjected to plasma processing, the operating life of the IC is not reduced, and no leakage current is generated in the insulating layer. Is not unstable, and furthermore, the destruction of the semiconductor element can be prevented.

In the discharge space 3, plasma active species, for example,
There are many electrons, ions, radicals, atoms, and the like. In particular, when He or Ar is used, many of these ions and radicals are present, and these active species excite a reactive gas, for example, oxygen and generate active species. When the plasma 4 containing the above-mentioned active species is transported from the discharge space 3 as in the present invention, ions and electrons among the above-mentioned active species die in a short time due to recombination, but radicals are relatively long. It has a long life, and in particular, a radical of He or Ar is considered to have a long life, and has high energy, so that it can survive after being discharged from the discharge space 3 and excite a reactive gas such as oxygen. It is. Therefore, the processing target 5 disposed downstream of the downstream electrode 1 can be effectively subjected to plasma processing. In addition, since these radicals have no charge, plasma treatment can be performed without damaging even charge-sensitive semiconductor elements and magnetic components for hard disks.

Here, the damage (charge-up damage) to the semiconductor chip by the charged particles will be described. FIG.
Is a sectional view of a semiconductor chip 50 of a MOSFET (MOS field effect transistor), 40 is a silicon substrate, 41 is an oxide film, 42 is a gate oxide film, 43 is a wiring made of aluminum or the like, and 44 is a gate electrode. , 45 indicate electrode pads for wire bonding, and 46 indicates a protective film. When such a semiconductor chip 50 is placed in the plasma 4, the charged particles 5 contained in the plasma 4
1 is injected from the electrode pad 45 into the wiring 43, and the charged particles 51 injected into the wiring 43 move in the wiring 43 as shown by the arrow in FIG. 5 to reach the gate electrode 44, and further, from the gate electrode 44. It is implanted into a gate oxide film 42 which is a thin oxide film. When the charged particles 51 in the gate oxide film 42 are stored in excess, the physical properties of the gate oxide film 42 are affected and the insulating layer (gate oxide film 42) is damaged. Specifically, gm (conductance), Vth (threshold voltage), and the like change as a result of the change in the physical characteristics of the gate oxide film 42. This is a phenomenon called charge-up damage. When such damage is given to the semiconductor chip 50, the operating life of the IC is shortened, the leakage current of the insulating layer is generated, and the element is destroyed. It can prevent problems from occurring.

As described above, the radicals of He and Ar have a long life, but the life is more extended when the radicals are released into the same gas atmosphere as the gas introduced into the discharge space 3 than into the air. It can be lengthened. Therefore, in the present invention, by filling the inside of the processing chamber 9 surrounded by the chamber 10 with the gas for plasma generation, the processing space formed on the downstream side of the downstream electrode 1 (the processing object 5 is disposed and the plasma The space to be processed) and the discharge space 3 are subjected to the plasma processing of the processing object 5 in substantially the same gas atmosphere, whereby the plasma 4 blown out from the discharge space 3 is included. Active species such as radicals can be prevented from dying before reaching the object 5, and the plasma 4 containing radicals or the like with high activity can reach the object 5 and be supplied. The processing efficiency can be increased.

FIG. 3 shows another embodiment. In this embodiment, without using a porous material as the downstream electrode 1,
The downstream electrode 1 is formed using the same flat cylindrical or cylindrical electrode as the upstream electrode 2. A plurality of electrodes 1 on the downstream side are arranged substantially horizontally. Further, the plurality of electrodes 1 are arranged so as to be arranged in the transport direction of the workpiece 5 (indicated by an arrow in FIG. 1), and a gap is provided between adjacent electrodes 1 as a gas outlet 31. ing. Each electrode 1 is disposed so that its longitudinal direction is orthogonal to the transport direction of the workpiece 5. Each electrode 1 is fixed to an insulating jig 22 provided on the inner surface of the processing chamber 9. I have. Other configurations are substantially the same as those of the embodiment shown in FIG.

It is preferable that the gas inlet 30 formed between the adjacent upstream electrodes 2 and the gas outlet 31 formed between the adjacent downstream electrodes 1 do not face each other vertically. When the gas introducing unit 30 and the gas deriving unit 31 are opposed to each other, the gas introduced into the discharge space 3 from the gas introducing unit 30 is easily led out from the gas deriving unit 31, so that discharge is less likely to occur in the discharge space 3 and high activity is achieved. There is a possibility that the plasma 4 containing the seeds is hardly generated and the performance of the plasma processing is reduced. Therefore, the electrode 1 on the downstream side is located immediately below the gas introduction unit 30 and the gas derivation unit 31
, So that the electrode 2 on the upstream side is located right above
It is preferable to arrange 2.

The interval between the adjacent upstream electrodes 2 can be formed in the same manner as in the embodiment shown in FIG. The distance between the adjacent downstream electrodes 1, that is, the dimension of the gas outlet 31 in the direction parallel to the transport direction of the workpiece 5 is preferably set to 2 mm or less. This interval is 2
If it is wider than mm, the flow rate of the plasma 4 flowing out from the discharge space 3 to the downstream side of the electrode 1 on the downstream side will decrease, and the plasma processing performance may be reduced. Also,
The distance between the adjacent downstream electrodes 2 is preferably 0.1 mm or more. If the distance is smaller than this, the pressure in the discharge space 3 becomes relatively high, so that the uniformity of discharge is lowered and the plasma 4 There is a possibility that the amount of air blown out becomes so small that plasma processing cannot be performed efficiently.

The embodiment shown in FIG. 1 flows out through the through-hole 21 to the downstream side (downward) of the electrode 1 on the downstream side, whereas the plasma processing apparatus shown in FIG. Gas outlet 31 formed between the electrodes 1
The plasma processing apparatus shown in FIG. 3 can perform plasma processing in the same manner as the plasma processing apparatus shown in FIG.

FIG. 4 shows another embodiment. In this embodiment, the processing chamber 9 is formed in the chamber 10 in FIG. 1, and the introduction chamber 11 and the extraction chamber 12 are not provided. Therefore, neither the inlet 13 nor the outlet 14 and the inlet 18 or the outlet 20 are formed. Further, the bottom of the chamber 10 is not provided, and the lower surface (downstream surface) of the processing chamber 9 is opened over the entire surface. Other configurations are shown in FIG.
It is formed similarly to the embodiment.

In this plasma processing apparatus, as in the embodiment shown in FIG. 1, the object 5 is placed on the roller 26 which is driven to rotate, so that the object 5 is conveyed in the direction of the arrow and Will pass under the electrode 1 of the first electrode.
The plasma 4 blown out from the through-hole 21 of the electrode 1
Is blown out below the chamber 10 through the lower surface opening of the processing chamber 9. Therefore, the processing target 5 is disposed downstream of the flow of the plasma 4 while passing through the processing chamber 9, whereby the surface (upper surface) of the processing target 5 is formed.
The plasma 4 is sprayed on the surface of the workpiece 5 to make contact therewith, and the surface of the workpiece 5 is subjected to plasma processing. In this embodiment, there is no need to operate the gate 6 when transporting the workpiece 5 as in FIG. 1, so that plasma processing can be easily performed and the plasma processing apparatus can be simplified. is there.

[0065]

The present invention will be described below in detail with reference to examples.

Example 1 The plasma processing apparatus shown in FIG. 1 was formed. As the electrode 2 on the upstream side, a cylindrical stainless steel electrode having an outer diameter of 6 mm and an inner diameter of 4 mm was used. On the surface of the electrode 2, a glassy film 7 composed mainly of titania and silica was formed with a thickness of 0.5 mm by thermal fusion. The withstand voltage of this coating 7 is 30 kV / mm.
Met. A 200 mesh stainless steel mesh (net) was used as the downstream electrode 1. These electrodes 1 and 2 were arranged facing each other at an interval of 5 mm. The electrode 2 on the upstream side was cooled by flowing pure water through the channel 23.

As a plasma generation gas, a mixed gas of helium, argon and oxygen was used. At this time, the helium flow rate was set to 3 liters / minute, the argon flow rate was set to 5 liters / minute, and the oxygen flow rate was set to 0.05 liters / minute. As the power supply 25, a high voltage (sine waveform) alternating at a frequency of 13.56 MHz is applied between the opposing electrodes 1 and 2, and 500
A power source of W was used. As the object to be processed 5, a glass plate for liquid crystal having an IC mounted on an end was used.

Then, a plasma treatment was performed on the surface of the glass plate as the object 5 in the same manner as described above. At this time, the plasma 4 was blown onto the glass plate for liquid crystal for 5 seconds. As a result, the contact angle of water on the glass plate was 40 degrees before the treatment, whereas the contact angle of water on the glass plate was 8 degrees after the treatment. It is considered that the reason why the contact angle of water changes as described above is that dirt such as organic substances present on the surface of the glass plate is removed by the plasma treatment. No charge-up damage due to the plasma 4 occurred in the IC.

(Example 2) A glassy film 7 composed mainly of titania and silica was formed on the surface of the electrode 1 of the mesh on the downstream side with a thickness of 0.5 mm by thermal fusion, and the plasma 4 was formed. Was performed on the glass plate in the same manner as in Example 1, except that the plasma treatment was performed for 3 seconds. As a result, the contact angle of water on the glass plate was 4 before treatment.
In contrast to 0 °, the contact angle of water on the glass plate became 8 ° after the treatment. No charge-up damage due to the plasma 4 occurred in the IC.

(Example 3) Instead of the vitreous coating 7, a ceramic coating 7 mainly composed of alumina was formed on the surface of the electrode 2 on the upstream side by ceramic spraying. This coating 7 has a thickness of 1 mm and a withstand voltage of 25 kV / m.
m. Further, a semiconductor mounting substrate (BGA, ball grid array) on which an IC (semiconductor) is mounted was used as the object 5 to be processed. Except for these, plasma treatment was performed in the same manner as in Example 1. As a result, the contact angle of water on the glass plate was 40 degrees before the treatment, whereas the contact angle of water on the glass plate was 8 degrees after the treatment. No charge-up damage due to the plasma 4 occurred in the IC.

Example 4 In the same manner as in Example 2 except that a ceramic coating 7 composed of titania was formed on the surface of the downstream electrode 1 by ceramic spraying instead of the glass coating 7. Plasma treatment was performed. As a result, the contact angle of water on the glass plate was 40 degrees before the treatment, whereas the contact angle of water on the glass plate was 8 degrees after the treatment. No charge-up damage due to the plasma 4 occurred in the IC.

Example 5 A plasma processing apparatus shown in FIG. 3 was formed. As the upstream electrode 2 and the downstream electrode 1, a cylindrical stainless steel electrode having an outer diameter of 6 mm and an inner diameter of 3 mm was used. On the surfaces of the electrodes 1 and 2, a ceramic coating 7 composed mainly of alumina was formed with a thickness of 0.5 mm by ceramic spraying. The pores of the coating 7 were sealed with silica. The withstand voltage of the coating 7 was 30 kV / mm. These electrodes 1 and 2 were arranged facing each other at an interval of 5 mm. The distance between adjacent upstream electrodes 2 and the distance between adjacent downstream electrodes 1 were each set to 1 mm. The electrodes 1 and 2 were cooled by flowing ion-exchanged water through the channel 23. The gas for plasma generation and the flow rate thereof were the same as in Example 1.
As the power supply 25 for generating an alternating high voltage, a power supply for generating a square-wave (pulse-shaped) pulse voltage at a rise time of 100 μs, an electric field strength of 50 kV / cm, and a frequency of 50 kHz is used. 500 in between
W power was turned on. As the object 5 to be processed, a liquid crystal panel on which a TFT was formed was used.

Then, a plasma treatment was performed on the surface of the glass plate as the object 5 in the same manner as described above. At this time, the plasma 4 was blown onto the glass plate for liquid crystal for 5 seconds. As a result, the contact angle of water on the glass plate was 40 degrees before the treatment, whereas the contact angle of water on the glass plate was 10 degrees after the treatment. It is considered that the reason why the contact angle of water changes as described above is that dirt such as organic substances present on the surface of the glass plate is removed by the plasma treatment. No charge-up damage due to the plasma 4 occurred in the TFT.

Example 6 The plasma processing apparatus shown in FIG. 4 was formed. As the electrode 2 on the upstream side, a cylindrical stainless steel electrode having an outer diameter of 6 mm and an inner diameter of 4 mm was used. On the surface of the electrode 2, a glassy film 7 composed mainly of titania and silica was formed with a thickness of 0.5 mm by thermal fusion. The withstand voltage of this coating 7 is 30 kV / mm.
Met. A 200 mesh stainless steel mesh (net) was used as the downstream electrode 1. These electrodes 1 and 2 were arranged facing each other at an interval of 5 mm. The electrode 2 on the upstream side was cooled by flowing pure water through the channel 23.

As a gas for plasma generation, a mixed gas of helium, argon and oxygen was used. At this time, the helium flow rate was set to 3 liters / minute, the argon flow rate was set to 5 liters / minute, and the oxygen flow rate was set to 0.05 liters / minute. As the power supply 25, a power supply that applies a high voltage (sinusoidal waveform) alternating at a frequency of 30 MHz between the opposing electrodes 1 and 2 and supplies 500 W of power between the electrodes 1 and 2 was used. IC to be processed 5
Was used at the end of the liquid crystal glass plate.

Then, a plasma treatment was performed on the surface of the glass plate as the object 5 in the same manner as described above. At this time, the plasma 4 was blown onto the glass plate for liquid crystal for 5 seconds. As a result, the contact angle of water on the glass plate was 40 degrees before the treatment, whereas the contact angle of water on the glass plate was 12 degrees after the treatment. It is considered that the reason why the contact angle of water changes as described above is that dirt such as organic substances present on the surface of the glass plate is removed by the plasma treatment. No charge-up damage due to the plasma 4 occurred in the IC.

(Comparative Example) The same procedure as in Example 1 was carried out except that a glass plate was introduced between the opposed electrodes 1 and 2 (discharge space 3) to perform a plasma treatment. As a result, the contact angle of water on the glass plate was 40 degrees before the treatment, whereas the contact angle of water on the glass plate became 8 degrees after the treatment. Destroyed by charge-up damage from.

[0078]

As described above, according to the first aspect of the present invention, the electrodes are arranged on the upstream side and the downstream side of the gas flow, and the electrodes on the upstream side and the electrodes on the downstream side are opposed to each other. A discharge space is formed between the discharge electrode and the downstream electrode, and a gas is supplied to the discharge space and an alternating high voltage is applied between the upstream electrode and the downstream electrode. Discharge in gas to generate plasma,
The plasma generated in the discharge space is caused to flow to the downstream side of the downstream electrode, and the plasma is supplied to the workpiece by disposing the workpiece on the downstream side of the downstream electrode. The object to be processed can be prevented from intervening between the electrodes, and the discharge state does not change depending on the presence or absence or the material of the object to be processed, and a uniform plasma can be generated. This makes it easier to perform uniform plasma processing on the workpiece. In addition, plasma can be supplied even to an object to be processed that is thicker than the distance between the electrodes, and plasma processing of a thick object to be processed can be performed without being affected by the distance between the electrodes. In addition, since the object to be processed is not directly exposed to the discharge space, even if the object to be processed is mounted with a semiconductor, it is possible to reduce the influence of the charged particles in the plasma on the semiconductor, and to reduce damage to the semiconductor due to the charged particles. Damage can be prevented.

Further, according to the invention of claim 2 of the present invention, the downstream electrode is formed of a porous material, and the plasma generated in the discharge space is made to pass through the downstream electrode so that the plasma generated in the discharge space can be made smaller than the downstream electrode. Since the plasma is discharged to the downstream side, the plasma generated in the discharge space can be substantially uniformly discharged from substantially the entirety of the electrode without bias, and the plasma can be sprayed substantially uniformly on the object to be processed, thereby achieving uniform plasma processing. Is what you can do.

According to the third aspect of the present invention, since the porous material is a mesh or a punching plate, the plasma generated in the discharge space is prevented by preventing the thickness of the downstream electrode from increasing. Side electrode can be passed in a short time, and the active species contained in the plasma can easily reach the workpiece before they die.
The effect of the plasma treatment can be increased.

According to the invention of claim 4 of the present invention, since the thickness of the porous material is 10 mm or less, the plasma generated in the discharge space is formed by forming the thickness of the downstream electrode to be 10 mm or less. This enables the active species contained in the plasma to pass through the electrode on the downstream side in a short time, easily reach an object to be processed before the active species dies, and the effect of the plasma processing can be enhanced.

Further, according to the invention of claim 5 of the present invention, the plasma generated in the discharge space by arranging a plurality of downstream electrodes and passing between the adjacent downstream electrodes can be used as the downstream electrode. Since it is made to flow to the downstream side more, plasma can be supplied to the object to be processed through between the adjacent downstream electrodes, and the object to be processed can be uniformly distributed in the direction along the space between the adjacent downstream electrodes. That can be processed.

According to the invention of claim 6 of the present invention, since the distance between adjacent electrodes is set to 2 mm or less, the flow rate of plasma flowing out of the discharge space to the downstream side of the downstream electrode can be increased. The effect of the plasma treatment can be improved.

Further, according to the invention of claim 7 of the present invention, since the downstream electrode has a flat cylindrical shape or a cylindrical shape, the electric field is not concentrated in the discharge space, and the electric field can be averaged, thereby reducing the generation of the streamer. Thus, the object to be processed can be prevented from being damaged by the streamer, and the plasma processing can be made more uniform. In addition, it is possible to flow the refrigerant to the downstream electrode, and it is possible to suppress a rise in the temperature of the downstream electrode by the refrigerant, and to reduce heat radiation from the downstream electrode, thereby thermally damaging the object to be processed. Can be prevented.

According to the invention of claim 8 of the present invention, since the downstream electrode is grounded, abnormal discharge from the electrode to the object to be processed can be prevented, and the object to be processed due to the abnormal discharge can be prevented. Damage can be prevented.

According to the ninth aspect of the present invention, since the alternating high voltage is a pulse voltage, a stable discharge can be generated in the discharge space, and a uniform plasma can be generated. Processing can be performed stably.

Further, in the invention of claim 10 of the present invention, since an electrode on which a ceramic or vitreous coating is formed is used, it is possible to prevent plasma or gas for generating plasma from coming into direct contact with the electrode. The electrode can be protected from the action of plasma sputtering and the action of gas corrosion, which can reduce the deterioration of the electrode and prevent impurities from being generated from the electrode for a long period of use. This also prevents the object from being contaminated by impurities.

According to the eleventh aspect of the present invention, since the withstand voltage of the coating is 2 to 50 kV / mm, the coating can withstand a high voltage applied between voltages.
This can prevent damage to the coating.

In the twelfth aspect of the present invention, since an electrode formed by coating a ceramic material by ceramic spraying is used, a streamer is formed between the upstream electrode and the downstream electrode by the coating. The generation can be suppressed, and the uniformity of the plasma processing can be further improved.

Further, according to the invention of claim 13 of the present invention, since an electrode formed by coating a vitreous material by heat fusion to form a coating film can be formed, a coating film with few pinholes can be formed. It is possible to suppress the dielectric breakdown of the electrode used as the starting point.

Further, in the invention according to claim 14 of the present invention, since the electrodes are cooled by the refrigerant, the temperature of the plasma can be prevented from rising, and the thermal damage to the object can be reduced. It is.

According to the fifteenth aspect of the present invention, the gas flow toward the discharge space is generated by the fan.
The gas can be forcibly sent to the discharge space, and the gas can be reliably introduced into the discharge space.
Gas can be blown to the electrode to cool the electrode. Further, it is possible to increase the flow rate of the plasma flowing out of the discharge space to the downstream side of the electrode on the downstream side, thereby improving the effect of the plasma processing.

According to the sixteenth aspect of the present invention, since an object to be processed is subjected to plasma processing in a processing chamber formed in the same gas atmosphere as the discharge space, plasma contained in the plasma blown out of the discharge space is included. Active species such as radicals can be prevented from dying before reaching the object to be treated,
The plasma containing radicals or the like having high activity can reach the object to be processed, and the effect of the plasma processing can be enhanced.

According to the seventeenth aspect of the present invention, the processing chamber is formed so as to be openable and closable by the gate. By closing the gate immediately after the introduction and departure of the object to be processed, the gas in the processing chamber can be made hard to flow out, the change in the gas concentration in the processing chamber can be reduced, and the uniformity can be obtained. It can perform plasma processing.

Further, according to the invention of claim 18 of the present invention, since the plasma processing is performed while continuously transporting a large number of workpieces, the plasma processing can be continuously performed on a large number of workpieces, The efficiency of the plasma processing can be increased.

According to a nineteenth aspect of the present invention, since the plasma processing is performed on the workpiece by the method according to any one of the first to eighteenth aspects, the workpiece is not interposed between the opposed electrodes. This makes it possible to eliminate the instability of the discharge due to the interposition of the object to be processed and to generate a uniform plasma, thereby facilitating uniform plasma processing of the object to be processed. It becomes. In addition, plasma can be supplied even to an object to be processed that is thicker than the distance between the electrodes, and plasma processing of a thick object to be processed can be performed without being affected by the distance between the electrodes.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views showing the same electrode.

FIG. 3 is a sectional view showing an example of another embodiment of the present invention.

FIG. 4 is a sectional view showing an example of another embodiment of the above.

FIG. 5 is a cross-sectional view illustrating an example of a semiconductor chip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 electrode 2 electrode 3 discharge space 4 plasma 5 workpiece 6 gate 7 coating 8 fan 9 processing chamber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H096 AA25 LA07 5F004 AA01 AA06 AA14 BA06 BB11 BB13 BB24 BB30 BC06 BC08 DA00 DA01 DA21 DA22 DA23 DA24 DA26 DA30 DB01 DB13 DB26 5F046 MA12

Claims (19)

[Claims] An electrode is arranged on the upstream side and the downstream side of a gas flow, and the upstream side electrode and the downstream side electrode are opposed to each other to form a discharge space between the upstream side electrode and the downstream side electrode, By supplying gas to the discharge space and applying an alternating high voltage between the upstream electrode and the downstream electrode, a discharge is generated in the gas at a pressure near the atmospheric pressure to generate plasma, and the plasma is generated in the discharge space. A plasma processing method comprising supplying generated plasma to an object to be processed by causing generated plasma to flow downstream of a downstream electrode and arranging the object to be processed downstream of the downstream electrode. . 2. The method according to claim 1, wherein the downstream electrode is formed of a porous material, and the plasma generated in the discharge space is caused to flow downstream of the downstream electrode by passing the downstream electrode. The plasma processing method according to claim 1. 3. The plasma processing method according to claim 2, wherein the porous material is a mesh or a punching plate. 4. The plasma processing method according to claim 2, wherein the thickness of the porous material is 10 mm or less. 5. A method in which a plurality of downstream electrodes are arranged and a plasma generated in a discharge space is caused to flow to a downstream side of the downstream electrodes by passing between adjacent downstream electrodes. The plasma processing method according to claim 1, wherein 6. The plasma processing method according to claim 5, wherein an interval between adjacent electrodes is set to 2 mm or less. 7. The plasma processing method according to claim 5, wherein the downstream electrode has a flat cylindrical shape or a cylindrical shape. 8. The plasma processing method according to claim 1, wherein the downstream electrode is grounded. 9. The plasma processing method according to claim 1, wherein the alternating high voltage is a pulse voltage. 10. The plasma processing method according to claim 1, wherein an electrode on which a ceramic or vitreous coating is formed is used. 11. The plasma processing method according to claim 10, wherein the withstand voltage of the coating is 2 to 50 kV / mm. 12. The plasma processing method according to claim 10, wherein an electrode having a coating formed by applying a ceramic material by ceramic spraying is used. 13. An electrode formed by coating a vitreous material by thermal fusion to form a film.
2. The plasma processing method according to 1. 14. The plasma processing method according to claim 1, wherein the electrodes are cooled by a coolant. 15. The plasma processing method according to claim 1, wherein a gas flow toward the discharge space is generated by a fan. 16. The plasma processing method according to claim 1, wherein an object to be processed is subjected to plasma processing in a processing chamber formed in a gas atmosphere substantially the same as the discharge space. 17. The plasma processing method according to claim 16, wherein the processing chamber is formed to be openable and closable by a gate. 18. The plasma processing according to claim 1, wherein the plasma processing is performed while continuously transporting a large number of workpieces.
8. The plasma processing method according to any one of 7. 19. A plasma processing apparatus for performing plasma processing on an object to be processed by the method according to claim 1. Description: