JP7084824B2 - Board processing equipment - Google Patents

Description

The present invention relates to a semiconductor wafer, a liquid crystal display substrate, a plasma display substrate, an organic EL substrate, a FED (Field Emission Display) substrate, an optical display substrate, a magnetic disk substrate, an optical magnetic disk substrate, and a photomask. The present invention relates to a substrate processing apparatus that performs predetermined processing on various substrates (hereinafter, simply referred to as substrates) such as substrates and substrates for solar cells, and particularly relates to plasma technology under atmospheric pressure.

Conventionally, the surface of a substrate is cleaned by using atmospheric pressure plasma that generates plasma in atmospheric pressure. In particular, among the substrates, semiconductor wafers are becoming finer and more highly integrated, and along with this, plasma damage introduced into the surface of the semiconductor wafer has become a problem. In order to avoid plasma damage and improve cleaning efficiency, a technique called submerged plasma, in which plasma is generated in a liquid to generate ions and radicals in the liquid, is being studied. However, since the plasma in the liquid generates plasma at the electrodes arranged in the liquid, there are problems of corrosion of the electrodes and elution of the electrode material into the liquid. Further, since plasma can be generated only in a local region between electrodes, it is difficult to apply it to the entire surface of a semiconductor wafer. Therefore, there is a demand for a technique capable of reliably and efficiently cleaning the entire surface of a semiconductor wafer.

As the device (first device) as described above, there is a surface cleaning device including a nozzle, a medium supply unit, and a pair of discharge electrodes (see, for example, Patent Document 1). The nozzle supplies a gas or liquid containing water molecules as a cleaning medium. The medium supply unit has a porcelain tube provided on the tip end side of the nozzle. The pair of discharge electrodes generate a streamer-like discharge with respect to the cleaning medium supplied from the medium supply unit through the inside of the porcelain tube to the object to be cleaned.

A high AC voltage is applied between the discharge electrodes to generate a streamer-like discharge, and the plasma-generated cleaning medium is sprayed onto the object to be cleaned to clean the surface of the object to be cleaned. This makes it possible to suitably clean the surface of an object to be cleaned such as a semiconductor wafer.

Further, as the device as described above (second device), there is a plasma generator provided with a liquid storage unit, a gas storage unit, a porous ceramic member, a linear electrode, and a cylindrical electrode (for example). , Patent Document 2). The liquid storage unit stores the liquid, and the gas storage unit stores the gas. The porous ceramic member separates the liquid accommodating portion and the gas accommodating portion. The linear electrodes are inserted inside the cylindrical electrodes, and these are arranged in a gas accommodating portion surrounded by a porous ceramic member.

A gas containing at least oxygen is supplied to the gas supply unit, and a voltage is applied between the linear electrode and the cylindrical electrode to generate plasma. Then, the gas containing ozone or oxygen radicals diffuses into the liquid in the liquid container as fine bubbles from the pores of the porous ceramics. As a result, after the ozone and various radicals are generated, the ozone and various radicals can be efficiently sent into the liquid in an extremely short time before they disappear.

Japanese Unexamined Patent Publication No. 2006-253495 Japanese Patent No. 5431537

However, in the case of the conventional example having such a configuration, there are the following problems.
That is, in the conventional first device, radicals and ions generated between the discharge electrodes may disappear before reaching the object to be cleaned. Further, since it is a streamer-like discharge, there is a problem that it takes a very long time to clean the entire surface of the semiconductor wafer and the throughput is poor.

In addition, the second device cleans the generated ozone and radicals with a cleaning liquid with a high concentration of ozone and radicals by diffusing them into the liquid before they disappear, but the metal constituting the porous ceramics. Elutes into the liquid, so there is a problem in cleaning semiconductor wafers that causes contamination.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a substrate processing apparatus capable of cleaning the entire surface of a substrate in a short time and preventing contamination by metal.

The present invention has the following configuration in order to achieve such an object.
That is, the invention according to claim 1 is a substrate processing apparatus for processing a substrate, in which a substrate holder for holding the substrate, a rotating means for rotating the substrate holder, and an upper portion of the substrate held by the substrate holder are arranged. A resin porous plate having a size that covers the entire surface of the substrate in a plan view, a mesh-like electrode arranged on the upper surface of the resin porous plate, and a discharge space above the mesh-like electrode are separated from each other. Gas is introduced into the arranged plate-shaped electrode, the treatment liquid supply port formed in the center of the plate-shaped electrode so as to penetrate the discharge space, and supplying the treatment liquid to the resin porous plate, and the discharge space. A plasma power supply that applies a voltage between the plate-shaped electrode and the mesh-shaped electrode to generate plasma in the discharge space is provided, and the lower surface of the resin porous plate and the substrate are provided. While the substrate is rotated by the rotating means while the space between the upper surface and the upper surface of the is filled with the treatment liquid, plasma is generated in the discharge space, and the active species generated in the discharge space by the plasma is made of the resin. It is characterized in that it is diffused in a treatment liquid in a plate to treat the upper surface of the substrate.

[Action / Effect] According to the invention according to claim 1, while rotating the substrate held in the substrate holder by a rotating means, plasma is generated in the discharge space, and ions and ozone generated in the discharge space by the plasma are generated. The active species such as the above are diffused into the treatment liquid in the resin porous plate, and the upper surface of the substrate is treated by the oxidizing action of the active species. Since the resin perforated plate has a size that covers the entire surface of the substrate in a plan view, the entire surface of the substrate can be processed at one time. Further, since the mesh electrode is arranged on the upper surface of the resin porous plate and is not immersed in the treatment liquid supplied to the resin porous plate, the metal of the mesh electrode is contained in the treatment liquid. Elution can be suppressed. Therefore, the entire surface of the substrate can be cleaned in a short time, and contamination by metal can be prevented.

Further, in the present invention, it is preferable that the resin porous plate is provided with a hydrophilic filter laminated on the substrate side and a hydrophobic filter laminated on the mesh-shaped electrode side (claim 2). ..

Since the hydrophilic filter can fill the treatment liquid between the entire upper surface of the substrate and the entire lower surface of the resin porous plate, the uniformity of the treatment on the entire upper surface of the substrate can be improved. Further, since the surface area of the treatment liquid on the discharge space side is increased by the hydrophobic filter, the active species generated by plasma can be efficiently dissolved and diffused in the treatment liquid in the resin porous plate.

Further, in the present invention, it is preferable that the gas introduction port is formed on the outer peripheral side of the treatment liquid supply port coaxially with the treatment liquid supply port, and gas is introduced downward and sideways (claim 3). ).

Since the gas inlet introduces the gas downward and laterally, the gas can be distributed over the entire discharge space extending laterally. Therefore, it is possible to evenly generate active species by plasma in the entire discharge space. As a result, the processing can be uniformly performed over the entire surface of the substrate.

Further, in the present invention, it is preferable that the discharge space is provided with a pressure adjusting valve for adjusting the pressure, and when the pressure in the discharging space increases, the pressure is reduced by the pressure adjusting valve (claim 4). ..

Since the discharge efficiency decreases as the pressure in the discharge space increases, the discharge efficiency can be maintained by reducing the pressure with the pressure regulating valve. Therefore, it is possible to suppress a decrease in plasma generation efficiency.

Further, in the present invention, the plasma power supply preferably outputs a high frequency voltage or a pulse voltage as the voltage (claim 5).

The plasma power source can efficiently generate plasma by applying a high frequency voltage or a pulse voltage to the discharge space.

According to the substrate processing apparatus according to the present invention, plasma is generated in the discharge space while the substrate held in the substrate holder is rotated by the rotating means, and active species such as ions and ozone generated in the discharge space by the plasma are generated. It is diffused in the treatment liquid in the resin porous plate to treat the upper surface of the substrate by the oxidizing action of the active species. Since the resin perforated plate has a size that covers the entire surface of the substrate in a plan view, the entire surface of the substrate can be processed at one time. Further, since the mesh electrode is arranged on the upper surface of the resin porous plate and is not immersed in the treatment liquid supplied to the resin porous plate, the metal of the mesh electrode is contained in the treatment liquid. Elution can be suppressed. Therefore, the entire surface of the substrate can be cleaned in a short time, and contamination by metal can be prevented.

It is a schematic block diagram which shows the whole structure of the substrate processing apparatus which concerns on Example. It is a vertical sectional view showing a part of a main part enlarged. It is a top view of the mesh electrode. It is a top view of the resin perforated plate.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an overall configuration of a substrate processing apparatus according to an embodiment, and FIG. 2 is a vertical sectional view showing a part of a main part enlarged.

The substrate processing apparatus according to this embodiment is a so-called single-wafer processing apparatus that processes circular substrates W one by one. In this substrate processing apparatus, for example, the upper surface of the substrate W is cleaned.

This substrate processing apparatus includes a holding unit 1, a processing unit 3, a supply unit 5, a plasma power supply 7, and a control unit 9.

The holding portion 1 includes a substrate holder 11, a rotating shaft 13, an electric motor 15, and a drainage recovery cup 17. The substrate holder 11 has substantially the same diameter as the substrate W in a plan view, and the substrate W to be processed is placed on the substrate holder 11. The substrate holder 11 holds the substrate W in a horizontal posture by, for example, vacuum suctioning or abutting and supporting the peripheral edge of the substrate W. The upper end of the rotary shaft 13 is connected to the center of the lower surface of the substrate holder 11, and the lower end is connected to the rotary shaft of the electric motor 15. The electric motor 15 is provided with a rotation axis in the vertical direction, and rotates the substrate holder 11 around the rotation center P.

The rotating shaft 13 and the electric motor 15 described above correspond to the "rotating means" in the present invention.

The processing unit 3 includes a cover 19, a resin perforated plate 21, a mesh-shaped electrode 23, a plate-shaped electrode 25, a processing liquid supply pipe 27, and a gas introduction pipe 29. The cover 19 is a tubular body having a circular shape in a plan view. A resin perforated plate 21 is attached to the lower part of the cover 19 inside. The processing unit 3 is moved to the holding unit 1 described later by a moving mechanism (not shown). The moving positions are at least two positions, a processing position shown in FIG. 1 and a standby position laterally separated from the processing position.

The resin porous plate 21 is formed by laminating resin-made porous members. The resin perforated plate 21 is attached to the inside of the cover 19 so that the lower surface thereof substantially coincides with the lower end surface of the cover 19. Specifically, as shown in FIG. 2, the resin perforated plate 21 is composed of a lower filter 21a configured by laminating hydrophilic filters and an upper filter 21b configured by laminating hydrophobic filters. Has been done.

The lower filter 21a is configured as a hydrophilic filter by laminating, for example, a resin-made hydrophilic membrane filter. The lower filter 21a is configured by stacking 10 hydrophilic membrane filters having a thickness of 10 to 100 μm and a pore size of 0.1 to 1.0 μm, for example. Further, the upper filter 21b is configured as a hydrophobic filter by laminating, for example, a hydrophobic membrane filter made of resin. The upper filter 21b is configured by stacking 10 hydrophobic membrane filters having a thickness of 10 to 100 μm and a pore size of 0.1 to 1.0 μm, for example.

The mesh-shaped electrode 23 is attached to the upper surface of the resin perforated plate 21, that is, the upper surface of the upper filter 21b. The mesh-shaped electrode 23 has, for example, an electrode thickness of about 1 to 2 mm and an electrode spacing corresponding to a mesh of 0.06 to 0.1 mm.

The plate-shaped electrode 25 constitutes the ceiling surface of the cover 19. The plate-shaped electrode 25 is provided with the lower surface thereof and the upper surface of the mesh-shaped electrode 23 separated by a predetermined distance. The plate-shaped electrode 25 has, for example, a thickness of about 2 mm. The above-mentioned predetermined distance is, for example, about 1 to 10 mm. Due to this predetermined distance, the space formed by the cover 19, the plate-shaped electrode 25, and the mesh-shaped electrode 23 is the discharge space 31. The discharge space 31 has a height of, for example, about 1 to 10 mm.

A supply port 33 is formed in the center of the plate-shaped electrode 25 in a plan view. One end side of the treatment liquid supply pipe 27 is inserted through the supply port 33. One end side thereof penetrates the discharge space 31 and is located inside the lower filter 21a near the lower surface of the resin perforated plate 21 and is open. The other end of the treatment liquid supply pipe 27 is connected to the supply unit 5. Specifically, it is communicated and connected to the processing liquid supply source 35 of the supply unit 5. The treatment liquid supply pipe 27 includes a control valve 37. The control valve 37 operates the flow of the treatment liquid in the treatment liquid supply pipe 27. The treatment liquid supply source 27 stores, for example, pure water and supplies the pure water to the treatment liquid supply pipe 27.

The above-mentioned supply port 33 corresponds to the "treatment liquid supply port" in the present invention.

One end side of the gas introduction pipe 29 is attached to the supply port 33. Specifically, the gas introduction pipe 29 is arranged on the outer peripheral side of the supply port 33 coaxially with the supply port 33 and the treatment liquid supply pipe 27 so as to cover the outer peripheral surface of the treatment liquid supply pipe 27. The lower end of the gas introduction pipe 29 is located above the lower end of the treatment liquid supply pipe 27. At the lower end of the gas introduction pipe 29, a lower hole 29a formed along the outer peripheral surface of the treatment liquid supply pipe 27 and a side hole 29b extending laterally from the outer peripheral surface of the treatment liquid supply pipe 27 are formed. ing. The lower hole 29a and the side hole 29b are communicated with each other in the discharge space 31. The lower hole 29a supplies gas toward the bottom surface of the discharge space 31, and the side hole 29b supplies gas toward the side surface and the bottom surface of the discharge space 31. In other words, the gas introduction pipe 29 introduces gas toward the lower side and the side of the discharge space 31 at the lower end portion. The other end side of the gas introduction pipe 29 is communicated with the gas supply source 39 of the supply unit 5. A control valve 41 is attached to the gas introduction pipe 29. The control valve 41 operates the gas flow in the gas introduction pipe 29. The gas supply source 39 stores, for example, argon and supplies it to the gas introduction pipe 29. The gas supply source 39 may supply helium, _{H2N2 (} forming gas), oxygen, hydrogen, and steam of the reactive gas instead of argon. In that case, each of them may be supplied alone or mixed with steam.

The gas introduction pipe 29, the lower hole 29a, and the side hole 29b described above correspond to the "gas introduction port" in the present invention.

A plasma power source 7 is electrically connected to the mesh-shaped electrode 23 and the plate-shaped electrode 25 described above. The plasma power source 7 outputs high frequency power or pulse voltage. Specifically, for example, in the case of a pulse voltage, a voltage of 0.1 to 20 kV is preferable at a frequency of 10 to 100 kHz. Further, in the case of high frequency power, power of 0.1 to 10 kW is preferable at a frequency of about 2 MHz or more.

A drainage recovery cup 17 having an annular shape in a plan view is arranged around the holding portion 1. The drainage recovery cup 17 collects the treatment liquid supplied to the upper surface of the substrate W and discharged to the surroundings, and causes the treatment liquid to flow down to a drainage treatment unit (not shown).

The processing unit 3 described above includes a pressure regulating valve 43. The pressure regulating valve 43 is attached to a pressure regulating tube 45 that is communicated with and connected to the discharge space 31. The pressure regulating valve 43 is normally closed, but is opened when the pressure in the discharge space 31 becomes high, and is operated to keep the pressure in the discharge space 31 substantially constant.

The movement of the processing unit 3 described above, the rotational drive of the electric motor 15, the opening / closing of the control valves 37 and 41, and the opening / closing of the pressure regulating valve 43 are collectively controlled by the control unit 9. The control unit 9 includes a CPU, a memory, and the like, and operates each unit according to preset cleaning processing conditions (cleaning time, rotation speed, plasma generation conditions, etc.).

Next, the processing of the substrate W by the substrate processing apparatus having the above-described configuration will be described. The pressure regulating valve 43 is in a closed state.

The control unit 9 moves the processing unit 3 to the standby position in order to place the substrate W to be processed on the substrate holder 11. In that state, the substrate W is placed on the substrate holder 11 with the processing surface of the substrate W facing up. Then, the control unit 9 lowers the processing unit 3 to the processing position shown in FIG.

Next, the control unit 9 opens the control valve 37 to supply the treatment liquid from the treatment liquid supply pipe 27. As a result, the treatment liquid is stored in the resin perforated plate 21. Further, since the lower filter 21a of the resin perforated plate 21 is hydrophilic, the treatment liquid can be densely filled between the entire upper surface of the substrate W and the entire lower surface of the resin perforated plate 21. The excess of the filled treatment liquid is collected in the drainage recovery cup 17 from the outer peripheral edge of the substrate W. The mesh-shaped electrode 23 is arranged on the upper surface of the resin porous plate 21, and since the upper portion of the resin porous plate 21 is a hydrophobic upper filter 21b, the treatment liquid is not densely filled. The mesh-shaped electrode 23 is not immersed in the treatment liquid supplied to the resin porous plate 21.

The control unit 9 opens the control valve 41 to supply the gas to the discharge space 31 before the supply of the treatment liquid, with the supply of the treatment liquid, or after the supply of the treatment liquid. The gas is supplied to the discharge space from the lower hole 29a and the side hole 29b as shown in FIG. The supply pressure at that time is preferably 0.1 to 0.4 MPa. The discharge space is filled with argon gas by the supply of this gas, but when the predetermined pressure is exceeded, the control unit 9 opens the pressure regulating valve 43 to prevent the pressure from further increasing.

The control unit 9 operates the plasma power supply 7 to apply a voltage between the mesh-shaped electrode 23 and the plate-shaped electrode 25. As a result, plasma is generated in the discharge space 31. In this plasma, active species such as O radical, OH radical, O ion and ozone are generated. The upper filter 21b of the resin perforated plate 21 on the bottom surface of the discharge space 31 is hydrophobic, and the surface area of the treatment liquid on the discharge space 31 side becomes large. Therefore, the active species generated in the discharge space 31 are efficiently dissolved and diffused in the treatment liquid in the resin porous plate 21.

In this state, the control unit 9 drives the electric motor 15 to rotate the substrate W with respect to the processing unit 3. Then, the treatment liquid containing the active species is supplied to the upper surface of the substrate W, and the treatment liquid is discharged laterally from the outer peripheral edge of the substrate W. At this time, organic substances are decomposed and removed from the upper surface of the substrate W by the oxidizing action of the active species. When this state is maintained for a predetermined processing time, the cleaning processing on the upper surface of the substrate W is completed.

When the processing time elapses, the control unit 9 moves the processing unit 3 to the standby position and stops the driving of the electric motor 15. Then, after shaking off and drying by the rotation of the substrate W, the processed substrate W is carried out from the substrate holder 11.

According to this embodiment, plasma is generated in the discharge space 31 while the substrate W held in the substrate holder 11 is rotated by the electric motor 15, and the active species generated in the discharge space 31 by the plasma is transferred to the resin porous plate 21. The upper surface of the substrate W is treated by the oxidizing action of the active species by diffusing into the treatment liquid inside. Since the resin perforated plate 21 has a size that covers the entire surface of the substrate W in a plan view, the entire surface of the substrate W can be processed at one time. Further, since the mesh-shaped electrode 23 is arranged on the upper surface of the resin-made porous plate 21 and is not immersed in the treatment liquid supplied to the resin-made porous plate 21, the metal of the mesh-shaped electrode 23 is formed. It is possible to suppress elution into the treatment liquid. Therefore, the entire surface of the substrate W can be cleaned in a short time, and contamination by metal can be prevented.

Further, since the gas introduction pipe 29 is provided with the lower hole 29a and the side hole 29b and introduces the gas downward and laterally, the gas can be distributed over the entire discharge space 31 extending laterally. can. Therefore, it is possible to evenly generate active species by plasma in the entire discharge space 31. As a result, the processing can be uniformly performed over the entire surface of the substrate W.

Further, since the discharge efficiency decreases as the pressure in the discharge space 31 increases, the discharge efficiency in the discharge space 31 can be maintained by reducing the pressure with the pressure regulating valve 43. Therefore, it is possible to suppress a decrease in plasma generation efficiency.

The present invention is not limited to the above embodiment, and can be modified as follows.

(1) In the above-described embodiment, the upper portion of the resin porous plate 21 is configured by a hydrophobic filter and the lower portion is configured by a hydrophilic filter, but the present invention is not limited to such a configuration.

(2) In the above-described embodiment, the gas introduction pipe 29 and the treatment liquid supply pipe 27 are coaxially configured, but the present invention does not require the coaxial configuration. Further, although the gas introduction pipe 29 includes a lower hole 29a and a side hole 29b, the gas introduction pipe 29 is not limited to such a configuration as long as the gas can be distributed to the discharge space 31.

(3) In the above-described embodiment, the pressure regulating valve 43 is provided, but the present invention does not require this configuration.

(4) In the above-described embodiment, the substrate holder 11, the cover 19, the mesh-shaped electrode 23, the plate-shaped electrode 25, and the like exhibit a circular shape that matches the shape of the circular substrate W, and the present invention has such a shape. Not limited to.

W ... Board 1 ... Holding unit 3 ... Processing unit 5 ... Supply unit 7 ... Plasma power supply 9 ... Control unit 11 ... Board holder 15 ... Electric motor 17 ... Drainage collection cup 19 ... Cover 21 ... Resin perforated plate 21a ... Lower filter 21b ... Upper filter 23 ... Mesh electrode 25 ... Plate electrode 27 ... Treatment liquid supply pipe 29 ... Gas introduction pipe 29a ... Lower hole 29b ... Side hole 31 ... Discharge space 33 ... Supply port 35 ... Treatment liquid supply source 37, 41 ... Control valve 39 ... Gas supply source 43 ... Pressure regulating valve

Claims (5)

In a board processing device that processes a board
A board holder that holds the board and
A rotating means for rotating the substrate holder and
A resin porous plate that is placed on the upper part of the substrate held by the substrate holder and has a size that covers the entire surface of the substrate in a plan view.
A mesh-shaped electrode arranged on the upper surface of the resin perforated plate and
A plate-shaped electrode arranged above the mesh-shaped electrode by a discharge space, and a plate-shaped electrode.
A treatment liquid supply port formed in the center of the plate-shaped electrode so as to penetrate the discharge space and supply the treatment liquid to the resin porous plate, and a treatment liquid supply port.
A gas inlet for introducing gas into the discharge space and
A plasma power supply that applies a voltage between the plate-shaped electrode and the mesh-shaped electrode to generate plasma in the discharge space, and
Equipped with
With the space between the lower surface of the resin perforated plate and the upper surface of the substrate filled with the treatment liquid, plasma is generated in the discharge space while the substrate is rotated by the rotating means, and the plasma is used in the discharge space. A substrate processing apparatus characterized in that the generated active species is diffused into a treatment liquid in the resin porous plate to treat the upper surface of the substrate. In the substrate processing apparatus according to claim 1,
The resin perforated plate is provided with a hydrophilic filter laminated on the substrate side, and a hydrophobic filter laminated on the mesh-shaped electrode side. In the substrate processing apparatus according to claim 1 or 2,
The substrate processing apparatus, wherein the gas introduction port is formed coaxially with the treatment liquid supply port on the outer peripheral side of the treatment liquid supply port, and introduces gas downward and laterally. In the substrate processing apparatus according to any one of claims 1 to 3,
The discharge space is provided with a pressure regulating valve for adjusting the pressure.
A substrate processing apparatus characterized in that when the pressure in the discharge space increases, the pressure is reduced by the pressure adjusting valve. In the substrate processing apparatus according to any one of claims 1 to 4,
The plasma power supply is a substrate processing apparatus characterized in that high frequency power or pulse voltage is output as the voltage.

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