JPH08330286A - Plasma treatment device - Google Patents

Abstract

PURPOSE: To make plasma damage distribution in a board surface uniform by making electrical and magnetic environment in a periphery of a treatment chamber uniform in a constitution enclosing a circumference of a treatment chamber with a conductor. CONSTITUTION: An entire of a treatment chamber 10 and an induction coil 18 is enclosed with a conductive cover 34 wherein a vertical axis passing through a central point of a board W is a symmetry axis and a starting point of a feedback side conductive path of a high frequency power supply 64 is set on a line of a vertical axis passing through a central point of a board or in the neighborhood thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma used for removing a photoresist film from the surface of a substrate or etching the surface of the substrate by using plasma in the manufacturing process of VLSI, for example. Regarding a processing device.

[0002]

2. Description of the Related Art As a plasma processing apparatus of this type, U.S. Pat. S. P. 5, 346, 578 and the like, in this plasma processing apparatus, a processing chamber (belger) mounted on a chamber base plate made of stainless steel with a coil (plasma source) disposed on the outer surface side. Of the substrate, and after supporting the substrate on the substrate mounting table made of a conductive material, the inside of the processing chamber is evacuated, and then the processing gas is introduced into the processing chamber,
A substrate is processed by applying a high frequency voltage to the coil through an impedance matching device by a high frequency power source to generate plasma inside the processing chamber and supplying the plasma to the surface of the substrate. Further, in this processing apparatus, the outer side of the processing chamber is surrounded by a housing made of stainless steel.

[0003]

By the way, in the vicinity of the processing chamber, if the metal wall surface such as the side wall surface of another device is located at an uneven position with respect to the processing chamber, the insulation property of the processing chamber from the metal wall surface is increased. The plasma inside the processing chamber is affected unevenly through the wall. In order to prevent the plasma inside the processing chamber from being affected by such an influence, a buffer space may be provided between the processing chamber and the metal wall surface. S. P. 5,
If the outer side of the processing chamber is surrounded by a housing formed of a metal material as in the plasma processing apparatus disclosed in 346 and 578, it is possible to cancel the influence of the plasma from the metal wall surface near the processing chamber. Therefore, it is not necessary to provide an unnecessary buffer space around the processing chamber, and the apparatus can be downsized. Further, by enclosing the outer side of the processing chamber and the coil with a housing, a part of the operator's body comes into contact with a coil to which a high voltage is applied and receives an electric shock or is exposed to a strong electromagnetic field near the coil. You can eliminate the danger.

On the other hand, since a metallic housing is provided outside the processing chamber and the coil with a slight space therebetween, a high-frequency current flowing into the metallic housing due to the stray capacitance between the housing and the processing chamber or coil, The return path to the high frequency power source is likely to be uneven with respect to the substrate arranged inside the processing chamber, and the magnetic field generated by the return current disturbs the plasma state around the substrate.
Then, even if the electrical and magnetic environment around the processing chamber becomes slightly uneven with respect to the substrate, the plasma damage distribution on the substrate surface is biased by reacting sensitively to the uneven environment. As a result, the processing quality of the substrate becomes non-uniform and the yield is reduced.

The present invention has been made in view of the above circumstances, and when the periphery of the processing chamber is surrounded by a conductor, the electrical and magnetic environment around the processing chamber is used as a substrate. It is an object of the present invention to provide a plasma processing apparatus that can make the plasma damage distribution on the surface of the substrate uniform by making it uniform, thereby making the processing quality of the substrate uniform and improving the yield.

[0006]

According to a first aspect of the present invention, there is provided a plasma processing apparatus in which a wall surface is formed of an insulating material, a gas introducing portion and a gas discharging portion are provided, and a substrate to be processed is horizontally placed inside. A processing chamber that can be housed and sealed, and
The entire plasma generating member disposed on the outer surface side of the processing chamber is made of a conductive material having an inner surface shape with a vertical axis passing through the center point of the substrate to be processed inside the processing chamber as a symmetrical axis. Enclosed by the formed conductive cover, the starting point position of the return side conductive path of the high frequency power source connected to the plasma generating member by a conductive line, the center point of the substrate to be processed arranged inside the processing chamber It is configured to be on or near the line of the vertical axis that passes. Here, the center point of the substrate to be processed is, for example, the center of a circle on a semiconductor wafer when the orientation flat and notch are ignored, and the center point of the liquid crystal display device (L
For a rectangular substrate for (CD), it refers to the intersection of the diagonal lines.

According to a second aspect of the present invention, in the plasma processing apparatus according to the first aspect, the conductive cover constitutes a part of a return side conductive path to the high frequency power source.

According to a third aspect of the present invention, in the plasma processing apparatus according to the second aspect, the processing chamber having an open lower end surface is processed on a plate-shaped base having a through hole formed of a conductive material. The lower end surface of the chamber is hermetically bonded to the upper surface of the plate-shaped base, and the upper surface of the substrate mounting surface is formed of a conductive material. The base is inserted into the through hole of the plate-like base so as to open and close the lower end surface side of the processing chamber to the atmosphere by reciprocating in the vertical direction relative to the base. A conductive cover is placed on the plate-shaped base, and between the plate-shaped base and the substrate mounting table and between the plate-shaped substrate base and the conductive cover, the entire circumference position or the processing chamber. Lead passing through the center of the substrate to be processed placed inside Wherein the shaft has electrically conductive is allowed in a plurality of positions which are equally spaced in a circumferential direction of a circle centering on the.

According to a fourth aspect of the present invention, in the plasma processing apparatus according to any one of the first to third aspects, the conductive cover is made of a material and a shape that shields light generated from the processing chamber. It is characterized in that it is configured by a wall surface, and a viewing window having an ultraviolet shielding filter is attached to a part of the wall surface.

According to a fifth aspect of the present invention, in the plasma processing apparatus according to any one of the first to fourth aspects, a charging side conductive path of a high frequency power source is provided between the processing chamber and the impedance matching device. The conductive wire core portion and the conductive sheath portion, which is formed in a tubular shape having the conductive wire core portion as an axis and serves as a conductive path on the return side of the high frequency power source, are connected by a coaxial conductive path forming body, The wire core portion and the inner surface of the conductive sheath portion are separated by an insulating space filled with gas, and the axial position of the conductive sheath portion formed of an insulating material is provided on the inner side of the conductive sheath portion. In addition, a plurality of core portion supporting members for supporting the conductive wire core portion are arranged at intervals in the axial direction of the conductive sheath portion.

According to a sixth aspect of the present invention, in the plasma processing apparatus according to the fifth aspect, the conductive sheath portion of the coaxial conductive path forming body is dividable.

The invention according to claim 7 is the plasma processing apparatus according to any one of claims 1 to 6, characterized in that the conductive cover is hermetically sealed.

The invention according to claim 8 is the plasma processing apparatus according to any one of claims 5 to 7, wherein a ventilation hole is formed in the core supporting member to form the coaxial conductive path forming member. The inside of the conductive sheath portion as a ventilation path, the conductive sheath portion as a conductive cover, at a position on or near a line of a vertical axis passing through the center point of the substrate to be processed disposed inside the processing chamber. It is characterized in that the inside of the conductive cover is connected to the exhaust means through the ventilation passage.

[0014]

In the plasma processing apparatus of the invention according to claim 1,
Since the entire plasma generating member of the processing chamber and the coils and electrodes arranged on the outer surface side of the processing chamber is surrounded by the conductive cover, the metal wall surface is located in an uneven position with respect to the processing chamber in the vicinity of the processing chamber. Even if it does, the influence from the metal wall surface is shielded by the conductive cover, and even if the buffer space is not provided around the processing chamber, the plasma inside the processing chamber is not unevenly affected by the metal wall surface. Further, it is possible to prevent a part of the operator's body from coming into contact with a coil or the like to which a high voltage is applied and receiving an electric shock or being exposed to a strong electromagnetic field near the coil or the like.

Further, in this plasma processing apparatus, the conductive cover has an inner surface shape with the vertical axis passing through the center point of the substrate to be processed inside the processing chamber as the axis of symmetry, and high frequency. The high-frequency current returning to the power supply flows out from a position on or near the line of the vertical axis that passes through the center point of the substrate to be processed, and the return path to the high-frequency power supply becomes even with respect to the substrate to be processed. . Therefore, the feedback current creates a magnetic field with the vertical axis passing through the center point of the substrate to be processed as a symmetrical axis, and the electrical and magnetic environment around the processing chamber becomes uniform with respect to the substrate. Therefore, the plasma damage distribution on the substrate surface becomes uniform.

In the plasma processing apparatus according to the second aspect of the present invention, the return current to the high frequency power source flows through the surface of the conductive cover. At this time, the conductive cover has an inner surface shape with the vertical axis passing through the center point of the substrate to be processed disposed inside the processing chamber as the axis of symmetry, so that the return current flowing on the surface of the conductive cover is It is even with respect to the substrate to be processed.

In the plasma processing apparatus according to the third aspect of the present invention, the return current to the high frequency power source is
It flows out from a position on or near the vertical axis line passing through the center point of the substrate to be processed placed inside the processing chamber,
It flows from the surface of the substrate mounting table to the surface of the conductive cover through the surface of the plate-shaped substrate. At this time, the conductive cover has an inner surface shape with the vertical axis passing through the center point of the substrate to be processed inside the processing chamber as an axis of symmetry, which is mounted on the plate-shaped base and Between the base and the substrate mounting table, and between the plate-shaped base and the conductive cover, electrically at the entire circumference position or at a plurality of positions equally arranged in the circumferential direction of the circle around the vertical axis. There is continuity. Therefore, the path of the return current formed by the substrate mounting table, the plate-shaped base and the conductive cover is
It is even with respect to the substrate to be processed.

In the plasma processing apparatus according to the fourth aspect of the present invention, the light emitted from the processing chamber is shielded by the ultraviolet shielding filters on the wall surface of the conductive cover and the viewing window. It is prevented that the eyes hurt. Further, observation of the plasma inside the processing chamber can be performed without any trouble through the viewing window.

In the plasma processing apparatus of the fifth aspect of the present invention, a high frequency voltage is applied to the plasma generating member from the high frequency power source through the charging side conductive path formed by the conductive wire core portion of the coaxial conductive path forming member, and the conductivity is increased. The high-frequency current returns to the high-frequency power source through the return-side conductive path formed by the sheath portion. And, the conductive wire core portion and the inner surface of the conductive sheath portion are separated by an insulating space filled with gas, and the support of the conductive wire core portion inside the conductive sheath portion is formed by an insulating material. Since it is made through a plurality of core supporting members, there is no fear of short-circuiting between the conductive wire core and the conductive sheath.

In the plasma processing apparatus according to the sixth aspect of the present invention, since the conductive sheath portion is configured to be dividable, it is easy to assemble, attach, and maintain the coaxial conductive path forming body.

The plasma generating member (plasma source) is generally classified into an inductively coupled type using a coil and a capacitively coupled type using an electrode. Also, while the high-density plasma can be generated by appropriately setting the applied power, strong ultraviolet rays are emitted at that time, and accordingly, high-concentration ozone is generated around the processing chamber. In the plasma processing apparatus of the invention according to claim 7, since the conductive cover has a closed shape, even if a high concentration of ozone is generated around the processing chamber, the ozone leaks out of the conductive cover. There is no need to worry that the working environment will deteriorate.

In the plasma processing apparatus of the eighth aspect of the present invention, the inside of the conductive cover is forcibly exhausted by using the inside of the conductive sheath portion of the coaxial conductive path forming body as a ventilation path. As a result, ozone generated inside the conductive cover can be exhausted, and even when the conductive cover is not in a completely sealed shape, the air outside the conductive cover is sucked into the conductive cover while the air is sucked into the conductive cover. Along with this, ozone can be exhausted from inside the conductive cover. At the same time,
The processing chamber, the plasma generating member, and the coaxial conductive path forming body itself are also cooled. And
Since the conductive sheath portion is connected to the conductive cover in a linear shape of a vertical axis passing through the center point of the substrate to be processed arranged inside the processing chamber or at a position in the vicinity thereof, the symmetry around the processing chamber is It is kept unbroken.

[0023]

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

FIG. 1 and FIG. 2 show one embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a main part of a plasma processing apparatus, a part of which is a vertical sectional view and a part of which is schematic. 2 is a plan view of the installation portion of the processing chamber.

This plasma processing apparatus has a processing chamber 10 formed of an insulating material such as quartz glass or ceramics, which is hemispherical, and the processing chamber 10 is a plate formed of a conductive material such as an aluminum material. It is mounted on the base 12, and the lower end surface of the processing chamber 10 and the upper surface of the plate base 12 are hermetically joined. Processing chamber 1
At the upper part of 0, the gas introduction port 1 communicating with the gas introduction pipe 14
6 is formed, and the gas introduction pipe 14 is connected to a gas supply unit (not shown) by a flow path. Further, the processing chamber 10 is provided with an induction coil 18 serving as a plasma source so as to surround the outer surface thereof. Since the induction coil 18 is thus arranged outside the processing chamber 10, there is no concern that the inside of the processing chamber 10 will be contaminated with metal. A circular stepped through hole 20 communicating with the internal space of the processing chamber 10 is formed in the plate-like base 12, and a substrate mounting table 22 is inserted into the stepped through hole 20. The space between the inner peripheral surface of the large-diameter portion of the stepped through hole 20 and the outer peripheral surface of the substrate mounting table 22 serves as an annular ventilation passage 24, and the exhaust passage 26 communicating with the annular ventilation passage 24 is plate-shaped. It is formed on the base 12. Exhaust path 26
Is connected to a vacuum exhaust unit (not shown) through a flow path.

The substrate mounting table 22 is made of a conductive material such as an aluminum material, has a heater (not shown) inside, and is adjusted to a temperature of 70 to 300 ° C., for example. The substrate mounting table 22 has an upper surface serving as a substrate mounting surface on which the substrate W is mounted, and although not shown, a plurality of, for example, three, which vertically reciprocate through through-holes formed therein. A substrate support member having a book support pin is provided. Further, a flange portion 28 is integrally formed on the lower end portion of the substrate mounting table 22.
The upper surface of the collar portion 28 and the lower surface of the plate-shaped base 12 are airtightly contacted with each other with the annular seal member 30 interposed. Further, on the upper surface side of the collar portion 28 of the substrate mounting table 22 or the lower surface side of the plate-shaped base 12, in order to electrically connect the substrate mounting table 22 and the plate-shaped base 12 when they abut. The conductive member 32 is fixed. Conductive member 32
Is a plurality of positions evenly arranged in the circumferential direction of a circle centered on the vertical axis passing through the center point of the substrate W arranged inside the processing chamber 10, or all positions of the circle, in this embodiment. It is arranged in an annular shape so that the substrate mounting table 22 and the plate-shaped base 12 are electrically connected at all circumferential positions.

The processing chamber 10, the plate-shaped base 12, and the substrate mounting table 22 are configured to relatively reciprocate in the vertical direction. For example, the substrate mounting table 22 is fixed on a pedestal (not shown), and the processing chamber 10 and the plate-shaped base 12 are held on the pedestal so as to be vertically reciprocally movable by an elevating and lowering drive mechanism (not shown). . Then, in a state where the processing chamber 10 and the plate-shaped base 12 are moved upward, an unprocessed substrate is carried into the processing chamber 10 by a substrate transfer mechanism (not shown),
The substrate is placed on the substrate placing surface of the substrate placing table 22.
After that, the processing chamber 10 and the plate-shaped base 12 descend, and the inside of the processing chamber 10 is hermetically closed. Further, after the processing of the substrate is completed, the processing chamber 10 and the plate-shaped base 12 are lifted to cause the processing chamber 10 to rise.
The inside of the chamber is opened to the atmosphere, and the processed substrate is carried out from the inside of the processing chamber 10 in this state.

In this plasma processing apparatus, a conductive cover 34 made of a conductive material such as an aluminum material is provided so as to surround the processing chamber 10 and the induction coil 18 as a whole. The conductive cover 34 has an inner surface shape with a vertical axis passing through the center point of the substrate W disposed inside the processing chamber 10 as a symmetrical axis, and in this embodiment, is formed in a cylindrical shape having a circular top plate. . The conductive cover 34 is mounted on the plate-shaped base 12, and the circular lower end surface of the conductive cover 34 is joined to the upper surface of the plate-shaped base 12 over the entire circumference, so that the conductive base 34 is connected to the plate-shaped base 12. It is electrically conducting. The conductive cover 34 and the plate-shaped base 1
The electrical connection with the two may be made only at a plurality of positions that are evenly arranged in the circumferential direction of the circular lower end surface of the conductive cover 34.

In the central portion of the top plate of the conductive cover 34,
The coaxial conductive path forming body 36 is connected. The coaxial conductive path forming body 36 includes a conductive wire core portion 38 and the conductive wire core portion 3
And a conductive sheath portion 40 formed in a tubular shape with the axis 8 as the axis. The conductive wire core portion 38 has a conductive sheath portion 40.
Is supported by a core portion support member 42 formed of an insulating material, for example, a fluororesin material, at an axial center position inside. A plurality of core supporting members 42 are arranged at intervals in the axial direction of the conductive sheath 40. Conductive sheath 4
The inside of 0 is filled with gas, for example, air, the conductive wire core portion 38 and the inner surface of the conductive sheath portion 40 are separated by an insulating space, and the conductive wire core portion inside the conductive sheath portion 40 is 38 is supported by an insulating core portion support member 42. Therefore, the conductive wire core portion 38 and the conductive sheath portion 40 are not electrically connected to each other.

As shown in FIG. 3, for example, the core portion supporting member 42 has a shape in which a bobbin is divided into two, and a conductive wire core portion is provided in a recess 44 formed in the center of each joint surface. By disposing 38 and joining both pieces, the conductive wire core portion 38 is configured to be supported at the center portion. In addition, a plurality of ventilation holes 46 are formed in the core support member 42. On the other hand, the conductive sheath 40 is, for example, as shown in FIG.
As shown in the front view in (A), the plan view in (B), the left side view in (C), and the longitudinal sectional view in the assembled state in (D), the pipe is taken along the axial direction. 2 in two
It is formed from one component piece 48, 48. Each piece 4
A flange 50 is integrally provided on each of the joint surfaces 8 and a flange 50 is formed with an insertion hole 52. The two flanges 50, which are formed by joining the two component pieces 48, 48 together and overlapping each other, are inserted into the respective insertion holes 52.
The conductive sheath portion 40 is assembled by inserting and attaching the screw 54 to and bonding. Then, the coaxial conductive path forming body 3
6, after the conductive wire core portion 38 is locked to the core portion supporting member 42 as described above, the core portion supporting member 42 is wrapped from both sides by the two constituent pieces 48, 48 of the conductive sheath portion 40. Then, the core portion supporting member 42 and the conductive wire core portion 38 are arranged on the inner side of both component pieces, and then, the conductive sheath portion 40 is assembled as described above.

A conductive wire core portion 38 of the coaxial conductive path forming member 36.
Has one end connected to the induction coil 18 and the other end connected to the impedance matching device 56. In addition, one end of the conductive sheath portion 40 is connected to the conductive cover 34 so as to be electrically connected to the conductive cover 34, and the inside of the conductive sheath portion 40 serves as a ventilation path 58. Communicates with the interior space of. The other end of the conductive sheath 40 is connected to the outer casing 60 of the impedance matching device 56, and the conductive sheath 40 and the outer casing 60 are electrically connected. Further, the ventilation passage 58 inside the conductive sheath portion 40 is connected to an exhaust pipe 62 which is provided so as to penetrate the wall surface of the outer casing 60 and which is connected to a vacuum pump (not shown) by a flow path. A high frequency power source 64 and an outer casing 66 thereof are connected to the impedance matching box 56 and the outer casing 60 thereof via a coaxial cable 68. The high frequency power supply 64 generates a high frequency current of, for example, several hundred KHz to several hundred MHz.

By the way, when the induction coil 18 is used as the plasma source as in this embodiment, strong ultraviolet light is emitted when the plasma is generated, and accordingly, a high concentration of ozone is generated around the processing chamber 10. It will be. In order to prevent this high-concentration ozone from diffusing to the surroundings, the conductive wire cover 34 may be hermetically sealed so that the ozone does not leak to the outside of the conductive cover 34. However, as in this embodiment, the inside of the conductive cover 34 is
If forced exhaust is performed through the air passage 58 inside the conductive sheath portion 40 of the coaxial conductive path forming body 36, the conductive cover 3 is used.
It is not necessary to make 4 completely sealed, and as shown in FIG. 5, an air suction hole 70 formed so as to block light emitted from plasma may be provided in the lower portion of the conductive cover 34. As described above, the air suction hole 7 is formed in the conductive cover 34.
0 is provided, and air is sucked into the conductive cover 34 through the air suction hole 70, and the air is combined with ozone,
By exhausting air through the air passage 58 inside the conductive sheath 40, the processing chamber 10 and the induction coil 1 are
8. Further, the coaxial conductive path forming body 36 itself can be cooled. Further, the conductive cover 34 is formed of a material that blocks light emitted from the processing chamber 10, and
When the processing chamber 10 is shaped so as to completely cover the periphery of the processing chamber 10 as in this embodiment, a peep window 72 is attached to the wall surface of the conductive cover 34 as shown in FIG. Processing chamber 10 therein
The state of plasma inside may be observed. At this time, the observation window 72 is provided with an ultraviolet shielding filter so that the observer does not hurt his eyes.

Next, the operation of the plasma processing apparatus having the above configuration will be briefly described by taking an example of ashing processing.

First, the processing chamber 10 and the plate-shaped base 12
The substrate having the photoresist film deposited on its surface is loaded into the processing chamber 10 in a state where
The processing chamber 10 and the plate-shaped base 12 are placed on the substrate mounting surface of the substrate mounting table 22, and the processing chamber 10 and the plate-shaped base 12 are lowered to hermetically close the inside of the processing chamber 10 as shown in FIGS. 1 and 6. When the inside of the processing chamber 10 is closed, the vacuum evacuation unit is activated to remove the air in the processing chamber 10 through the annular ventilation passage 24 and the exhaust passage 26. Next, while introducing the processing gas, for example, oxygen gas, which is fed from the gas supply unit through the gas introduction pipe 14 into the processing chamber 10 through the gas introduction port 16, vacuum exhaust is continued and the inside of the processing chamber 10 is desired. Vacuum pressure, for example, tens of mTo
Keep at rr to several Torr. Then, a high-frequency current is passed through the induction coil 18, plasma is generated inside the processing chamber 10, and the ashing process of the substrate is performed. When the processing is completed, a purge gas such as nitrogen gas is introduced from the gas supply unit into the processing chamber 10 through the gas introduction port 16 and the inside of the processing chamber 10 is returned to the atmospheric pressure. When the inside of the processing chamber 10 returns to atmospheric pressure, the processing chamber 10 and the plate-shaped base 12 rise, the inside of the processing chamber 10 is opened, and the processed substrate is unloaded from the inside of the processing chamber 10.

The processing in this plasma processing apparatus is performed as described above. During the plasma processing, a coaxial conductive path is formed from the high frequency power source 64 to the induction coil 18 as shown in FIGS. 6 and 7. A high frequency charging current 74 flows through the conductive wire core portion 38 of the body 36 as a conductive path.
Further, the high frequency return current 76 flows out from the surface of the substrate mounting table 22 from a position on or near the line of the vertical axis passing through the center point of the substrate W, and conducts from the surface of the substrate mounting table 22 via the plate-shaped base 12. Flows into the surface of the conductive cover 34, flows from the conductive cover 34 to the conductive sheath portion 40 of the coaxial conductive path forming body 36 connected to the central portion of the top plate, and uses the conductive sheath portion 40 as a conductive path. It returns to the high frequency power supply 76. At this time, the substrate mounting table 22, the conductive member 32,
Plate-shaped base 12, conductive cover 34, and conductive cover 34
Each of the connecting portions of the coaxial conductive path forming body 36 with respect to is completely symmetrical with respect to the vertical axis passing through the center point of the substrate W. Therefore, the stray capacitance 78 between the wall surface of the processing chamber 10 and the conductive cover 34 and the stray capacitance 80 between the induction coil 18 and the conductive cover 34 are provided by the conductive cover 34.
The paths of the feedback currents 76 flowing through are not uneven, and the paths of the feedback currents 76 are even with respect to the substrate W in the circumferential direction of a circle centered on the center point of the substrate W. Therefore, the magnetic field generated by the feedback current 76 does not disturb the state of the plasma 82 around the substrate W, and the plasma damage distribution on the substrate W becomes uniform. In addition, 84 in FIG. 6 is a sheath capacitance between the plasma 82 and the substrate W,
86 schematically shows the sheath volume between the plasma 82 and the wall surface of the processing chamber 10.

Although the induction coil 18 is used as the plasma source in the above embodiment, an electrode may be used as the plasma source. Further, in the above embodiment, the inside of the conductive sheath portion 40 of the coaxial conductive path forming body 36 is used as the ventilation path 58 to exhaust the inside of the conductive cover 34. Alternatively, the exhaust passage may be provided in a form symmetrical with respect to a vertical axis passing through the center point of the substrate arranged inside the processing chamber. Also, the shape of the conductive cover is not limited to the circular cylinder with the circular top plate as in the above-mentioned embodiment, and may be any symmetrical shape. Further, it is not necessary to have the closed shape as shown in FIG. Not necessarily. Furthermore, although the conductive cover 34 is part of the return-side conductive path to the high-frequency power source in the above-described embodiment, the conductive wire is provided on the substrate mounting table on or near the vertical axis passing through the center point of the substrate. May be connected, and a high frequency current may be returned to the high frequency power source through the conductive wire.

[0037]

According to the plasma processing apparatus of the first aspect of the present invention, even if the metal wall surface such as the side wall surface of another apparatus is located in an unequal position with respect to the processing chamber in the vicinity of the processing chamber. In addition, it is possible to prevent the plasma from being unevenly influenced through the wall surface of the processing chamber from the metal wall surface without providing a useless buffer space around the processing chamber, and the apparatus can be downsized. Further, there is no concern that a part of the operator's body touches the plasma source of the coil or the electrode to which a high voltage is applied to receive an electric shock or is exposed to a strong electromagnetic field in the vicinity of the plasma source, thus improving safety. Then, by using this plasma processing apparatus, the electrical and magnetic environment around the processing chamber is made uniform with respect to the substrate,
The plasma damage distribution on the substrate surface can be made uniform, so that the processing of the substrate can be stabilized, the quality of the substrate can be made uniform, and the yield can be improved. Furthermore, the electrical and magnetic environment around the processing chamber is equalized with respect to the substrate, so that it is possible to prevent arc-like local discharge that occurs in a narrow path for evacuation inside the processing chamber. Therefore, it becomes possible to stably apply a larger electric power to the plasma source, and therefore, the processing speed can be increased and the throughput can be improved.

In the plasma processing apparatus according to the second aspect of the present invention, the return current to the high frequency power source flows through the conductive cover, and the high frequency current return path is even with respect to the substrate to be processed. The above-mentioned effects of the invention are surely exhibited.

In the plasma processing apparatus according to the third aspect of the present invention, the return current to the high frequency power supply is on the vertical axis line passing through the center point of the substrate to be processed arranged inside the processing chamber on the surface of the substrate mounting table. It flows out from a nearby position, flows from the substrate mounting table through the plate-shaped base into the conductive cover,
The high-frequency current return path is even with respect to the substrate, and the above-described effect of the invention according to claim 1 is reliably exhibited.

In the plasma processing apparatus according to the fourth aspect of the present invention, it is possible to observe the plasma inside the processing chamber during the plasma processing, and it is possible to prevent the light emitted from the processing chamber from damaging the eyes of the observer. The plasma can be safely observed.

In the plasma processing apparatus according to the fifth aspect of the present invention, since the charge side conductive path and the return side conductive path of the high frequency power source are formed by one coaxial conductive path forming member, the high frequency power source and the processing chamber are formed. Wiring between them is simplified, and wiring work is also simplified.

In the plasma processing apparatus according to the sixth aspect of the present invention, work such as assembling, mounting, and maintenance of the coaxial conductive path forming body is facilitated.

In the plasma processing apparatus according to the seventh aspect of the present invention, even if a high concentration of ozone is generated around the processing chamber, there is a concern that ozone will leak to the outside of the conductive cover and deteriorate the work environment. Especially, when a inductively coupled plasma source using a coil is used, a great effect is exhibited.

In the plasma processing apparatus according to the eighth aspect of the present invention, ozone generated inside the conductive cover can be exhausted, and even if the conductive cover does not have a completely sealed shape, the outside of the conductive cover can be eliminated. The ozone can be exhausted from the inside of the conductive cover together with the air while sucking the air into the inside of the conductive cover, which is particularly effective when an inductively coupled plasma source using a coil is used.
Further, when the air sucked into the conductive cover is exhausted, the processing chamber, the plasma generating member, and the coaxial conductive path forming member itself can be cooled at the same time. Since it is not necessary to provide a special device, the structure of the device can be simplified and the space can be saved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part of a plasma processing apparatus showing one embodiment of the present invention, in which a part is a longitudinal section and a part is a schematic view.

2 is a plan view of an installation portion of a processing chamber of the apparatus shown in FIG.

FIG. 3 is a perspective view showing an example of a core portion support member used for a coaxial conductive path forming body, which is one of the components of the apparatus shown in FIG. 1, in a divided state.

4A and 4B are views showing an example of a conductive sheath portion which is also used in the coaxial conductive path forming body, in which FIG. 4A is a front view in a separated state, FIG. Similarly, () is a left side view, and (D) is a longitudinal sectional view in an assembled state.

5 is an external perspective view showing an example of a conductive cover of the apparatus shown in FIG.

6 is a schematic configuration diagram for explaining flows of a high frequency charging current and a high frequency feedback current in the device shown in FIG.

FIG. 7 is a plan view of the same for explaining.

[Explanation of symbols]

 10 Processing Chamber 12 Plate Base 16 Gas Inlet 18 Induction Coil 20 Plated Base Stepped Through Hole 22 Substrate Placement Table 26 Exhaust Path 32 Conductive Member 34 Conductive Cover 36 Coaxial Conductor Forming Body 38 Conductive Wire Core Part 40 Conductive sheath part 42 Core part support member 44 Recessed part 46 Vent hole 56 Impedance matching device 58 Vent path 62 Exhaust pipe 64 High frequency power supply 70 Air suction hole 72 Peep window 74 High frequency charging current 76 High frequency feedback current W substrate

Claims (8)

[Claims] 1. A processing chamber having a wall formed of an insulating material, having a gas introducing part and a gas discharging part, capable of accommodating and sealing a substrate to be processed in a horizontal posture, and an outer surface side of the processing chamber. In a plasma processing apparatus comprising: a plasma generating member disposed in the plasma generating member; and a high frequency power source connected to the plasma generating member via an impedance matching device by a conductive wire, the processing chamber and the plasma generating member as a whole. A feedback side of the high-frequency power source, which is surrounded by a conductive cover having an inner surface shape having a vertical axis as a symmetry axis and passing through a center point of a substrate to be processed which is disposed inside the processing chamber, and which is formed of a conductive material. The starting point position of the conductive path is on or near the line of the vertical axis passing through the center point of the substrate to be processed arranged inside the processing chamber. That the plasma processing apparatus. 2. The plasma processing apparatus according to claim 1, wherein the conductive cover constitutes a part of a return side conductive path of the high frequency power source. 3. A lower end surface of the processing chamber is opened, and the processing chamber is hermetically sealed on a plate-shaped base formed of a conductive material and having a through hole and the lower end surface of the processing chamber being on an upper surface of the plate-shaped base. The substrate mounting table is made of a conductive material and has an upper surface serving as a substrate mounting surface. The substrate mounting table and the processing chamber and the plate-shaped base reciprocate in the vertical direction relative to each other. The conductive cover is mounted on the plate-shaped base so that the lower end surface side of the processing chamber is opened to the atmosphere and airtightly closed by moving the processing chamber. The plate-shaped base and the substrate mounting table, and the plate-shaped substrate and the conductive cover are provided at the entire circumference position or the center point of the substrate to be processed arranged inside the processing chamber. Plural equally distributed in the circumferential direction of a circle centered on the passing vertical axis The plasma processing apparatus according to claim 2, wherein the plasma processing apparatus is electrically connected at a position. 4. The conductive cover is composed of a wall surface of a material and a shape that shields light emitted from the processing chamber, and a part of the wall surface is provided with a viewing window having an ultraviolet shielding filter. The plasma processing apparatus according to any one of claims 1 to 3. 5. A conductive wire core portion, which serves as a charging-side conductive path of the high frequency power supply, is formed between the processing chamber and the impedance matching device, and is formed in a cylindrical shape with the conductive wire core portion as an axis line. It is connected by a coaxial conductive path forming body composed of a conductive sheath portion which serves as a return side conductive path, and the conductive wire core portion and the inner surface of the conductive sheath portion are separated by an insulating space filled with gas. Along with the inner side of the conductive sheath, a core support member that is formed of an insulating material and supports the conductive wire core at the axial center of the conductive sheath is provided in the axial direction of the conductive sheath. The plasma processing apparatus according to any one of claims 1 to 4, wherein a plurality of the plasma processing apparatuses are arranged at intervals. 6. The plasma processing apparatus according to claim 5, wherein the conductive sheath portion of the coaxial conductive path forming member is dividable. 7. The plasma processing apparatus according to claim 1, wherein the conductive cover has a closed shape. 8. A ventilation hole is formed in the core supporting member, the inside of the conductive sheath portion of the coaxial conductive path forming body is used as a ventilation passage, the conductive sheath portion is used as a conductive cover, and the inside of the processing chamber is used. 5. The connection is made at a position on or near a line of a vertical axis passing through the center point of the substrate to be processed arranged at, and the inside of the conductive cover is connected to an exhaust means by a flow path through the ventilation path. 7. The plasma processing apparatus according to any one of 7.