JP7828789B2 - Plasma processing equipment - Google Patents

Description

Embodiments of the present invention relate to a plasma processing apparatus.

In plasma processing equipment used for dry etching, CVD, PVD, and other processes, there is a demand for improved plasma processing performance, such as processing rate. Furthermore, in recent years, with the miniaturization of processing components, precision in process control has become increasingly important.

If by-products generated during plasma treatment remain inside the chamber, the plasma treatment performance may fluctuate, making precise process control impossible. In this case, cleaning or replacing the elements contaminated with by-products inside the chamber can restore precise process control. However, if maintenance becomes frequent or time-consuming, the operating rate of the plasma treatment device will decrease.

Therefore, a plasma processing apparatus has been proposed in which a mounting section for placing the material to be processed is supported inside the chamber, and a turbomolecular pump is positioned directly below the mounting section (see, for example, Patent Document 1). Such a plasma processing apparatus allows for a high effective exhaust velocity and unbiased, axially symmetric exhaust. Therefore, it becomes easy to discharge by-products generated during plasma processing to the outside of the chamber.

However, it is impossible to completely prevent by-products from adhering to the elements inside the chamber. Therefore, when cleaning or replacing elements contaminated with by-products, a procedure called atmospheric venting is performed, which increases the internal pressure of the chamber. If the high-velocity turbomolecular pump is stopped during atmospheric venting, it takes a considerable amount of time for the pumping speed to stabilize after restarting. Therefore, a valve is provided to hermetically seal the connection between the chamber and the turbomolecular pump. With such a valve in place, the turbomolecular pump can remain operational during atmospheric venting.

However, depending on the process conditions (e.g., processing pressure and type of process gas), the generated plasma may reach the vicinity of the valve. Furthermore, the valve is equipped with a sealing element (e.g., an O-ring) for airtight closure. Therefore, if the generated plasma reaches the vicinity of the valve, the sealing element may be damaged by plasma products such as ions and electrons. Damage to the sealing element can lead to the generation of particles, potentially causing contamination of the processed material.
Therefore, there was a need for the development of a plasma processing apparatus that could suppress damage to sealing components caused by plasma products.

Japanese Patent Publication No. 2013-211269

The problem that this invention aims to solve is to provide a plasma processing apparatus that can suppress damage to the sealing member caused by plasma products.

The plasma processing apparatus according to this embodiment comprises: a chamber capable of maintaining an atmosphere reduced to atmospheric pressure; a plasma generating unit capable of generating plasma inside the chamber; a gas supply unit capable of supplying process gas to the plasma generation region inside the chamber; a mounting module having a cantilever structure and capable of supporting a mounting section on which a workpiece is placed below the plasma generation region; a pump capable of exhausting the inside of the chamber through a hole provided in the bottom plate of the chamber; a plate-shaped valve body capable of opening and closing the hole provided in the bottom plate of the chamber; a drive unit capable of changing the position of the valve body in the direction of the central axis of the chamber; an annular sealing member provided on the bottom plate side surface of the valve body or on the bottom plate; and a shielding portion provided between the aforementioned mounting module and the valve body, having at least one hole penetrating in the thickness direction, being conductive, and grounded.

According to embodiments of the present invention, a plasma processing apparatus is provided that can suppress damage to a sealing member by plasma products.

This is a schematic cross-sectional view illustrating the plasma processing apparatus according to this embodiment. This is a schematic perspective view illustrating a mounting module. This is a schematic cross-sectional view of the mounting module. (a) and (b) are schematic plan views illustrating cases where multiple holes are provided in the shielding portion.

The embodiments will be illustrated below with reference to the drawings. In each drawing, similar components are denoted by the same reference numerals, and detailed descriptions will be omitted as appropriate.
Furthermore, in this specification, "planar dimension" refers to the dimension in a direction perpendicular to the central axis of the chamber.

Figure 1 is a schematic cross-sectional view illustrating the plasma processing apparatus 1 according to this embodiment. Figure 2 is a schematic perspective view illustrating the mounting module 3.
Figure 3 is a schematic cross-sectional view of the mounting module 3.

As shown in Figure 1, the plasma processing apparatus 1 includes, for example, a chamber 2, a mounting module 3, a power supply unit 4, a power supply unit 5, a pressure reduction unit 6, a gas supply unit 7, a controller 8, and a shielding unit 9.

Chamber 2 has an airtight structure that can maintain an atmosphere at a pressure lower than atmospheric pressure.
Chamber 2 includes, for example, a main body 21, a top plate 22, and a window 23.
The main body 21 has a substantially cylindrical shape, with a bottom plate 21a integrally provided at one end. The other end of the main body 21 is open. The main body 21 is made of a metal such as an aluminum alloy. The main body 21 is also grounded. A region 21b where plasma P is generated is provided inside the main body 21. The main body 21 is provided with an input/output port 21c for loading and unloading the material 100. The input/output port 21c is hermetically closed by a gate valve 21c1.

The processed object 100 can be, for example, a photomask, mask blank, wafer, glass substrate, etc. However, the processed object 100 is not limited to those exemplified.

The top plate 22 is plate-shaped and is provided to cover the opening of the main body 21. The top plate 22 faces the bottom plate 21a. A hole 22a is provided in the central region of the top plate 22, penetrating in the thickness direction. The central axis of the hole 22a coincides with the central axis 2a of the chamber 2. The hole 22a is provided to allow electromagnetic waves radiated from the electrode 51 (described later) to pass through. The top plate 22 is formed from a metal such as an aluminum alloy.

The window 23 is plate-shaped and is provided on the top plate 22. The window 23 is positioned to block the hole 22a. The window 23 is made of a material that allows electromagnetic fields to pass through and is resistant to etching during etching. For example, the window 23 can be made of a dielectric material such as quartz.

A hole 2b is provided on the side of the chamber 2. The hole 2b is sized and shaped to allow the mounting portion 31, which is attached to the mounting portion 32a (described later), to pass through (see Figure 2). Therefore, the mounting module 3, with the mounting portion 31, can be removed from the chamber 2, or attached to the chamber 2, through the hole 2b. Furthermore, when the mounting module 3 is attached to the chamber 2, the central axis of the mounting portion 31 on the mounting module 3 aligns with the central axis 2a of the chamber 2. A slider can also be provided on the outer wall of the chamber 2 to facilitate the attachment and removal of the mounting module 3.

As shown in Figures 1 to 3, the mounting module 3 has a mounting section 31, a support section 32, and a cover 33.
The mounting module 3 has a cantilever structure and supports a mounting section 31 on which the workpiece 100 is placed, below the region 21b where the plasma P is generated.
The mounting module 3 protrudes into the chamber 2 from its side. A mounting section 31 is provided at the tip of the mounting module 3. If the mounting module 3 has a cantilever structure, a space is created below the mounting section 31 located in the internal space of the chamber 2. Therefore, the depressurization section 6 can be positioned directly below the mounting section 31, concentrically with the mounting section 31. In this way, it becomes easy to achieve a high effective exhaust velocity and axially symmetric exhaust without bias. As a result, it becomes easy to discharge by-products generated during plasma processing to the outside of the chamber 2. Consequently, precise process control becomes possible. In addition, since the adhesion of by-products to the inner wall of the chamber 2 and the mounting module 3 can be suppressed, the number of maintenance cycles and the time required for maintenance can be reduced. Therefore, the operating rate of the plasma processing apparatus 1 can be improved.

Furthermore, if the mounting module 3 has a cantilever structure, it can be attached to or removed from the chamber 2 from a direction perpendicular to the central axis 2a of the chamber 2. Therefore, maintenance of the plasma processing apparatus 1 becomes easier compared to a case where the mounting section is fixed to the bottom plate 21a of the chamber 2.

The object to be processed 100 is placed on the placement section 31.
The mounting section 31 includes, for example, an electrode 31a, an insulating ring 31b, and a base 31c. The electrode 31a is formed from a conductive material such as metal. The upper surface of the electrode 31a can serve as a mounting surface for placing the workpiece 100. The electrode 31a is, for example, screwed to the base 31c.

Furthermore, the electrode 31a can incorporate pickup pins 31a1 and a temperature control unit. Multiple pickup pins 31a1 can be provided. These multiple pickup pins 31a1 are rod-shaped and can protrude from the upper surface of the electrode 31a. The multiple pickup pins 31a1 are used when transferring the workpiece 100. Therefore, the multiple pickup pins 31a1 are capable of protruding from the upper surface of the electrode 31a and retracting into the electrode 31a by a drive unit (not shown).

The temperature control unit includes, for example, a refrigerant circulation line (flow path) and a heater. The temperature control unit controls the temperature of the electrode 31a, and consequently the temperature of the workpiece 100 placed on the electrode 31a, based on the output from, for example, a temperature sensor (not shown).

The insulating ring 31b is ring-shaped and covers the side surface of the electrode 31a. The insulating ring 31b is formed from a dielectric material such as quartz.
The base 31c is provided between the electrode 31a and the mounting portion 32a of the support portion 32. The base 31c insulates the electrode 31a from the support portion 32. The base 31c is made of a dielectric material such as quartz. The base 31c is screwed to the mounting portion 32a of the support portion 32, for example.

The support portion 32 supports the mounting portion 31 within the internal space of the chamber 2. The support portion 32 is positioned to extend between the side surface of the chamber 2 and below the mounting portion 31.
The support portion 32 includes, for example, a mounting portion 32a, a beam 32b, and a flange 32c. The mounting portion 32a, beam 32b, and flange 32c are formed from, for example, an aluminum alloy.

The mounting portion 32a is located within the internal space of the chamber 2, below the mounting portion 31. The mounting portion 32a is cylindrical. A hole 32a1 is provided on the side of the mounting portion 32a facing the mounting portion 31 (see Figure 3). A hole 32a2 is provided on the side of the mounting portion 32a opposite to the mounting portion 31. Wiring members 42c and refrigerant piping are connected to the electrode 31a via hole 32a1. Hole 32a2 is used for connecting wiring members 42c and refrigerant piping, and for maintenance of the electrode 31a. The mounting portion 31 (base 31c) is provided on the side of the mounting portion 32a facing the mounting portion 31. Therefore, the planar shape of the mounting portion 32a can be the same as the planar shape of the mounting portion 31. The planar dimensions of the mounting portion 32a can be approximately the same as or slightly larger than the planar dimensions of the mounting portion 31.

One end of beam 32b is connected to the side surface of mounting portion 32a. The other end of beam 32b is connected to flange 32c via a hole 2b that penetrates the side surface of chamber 2. Beam 32b extends through the internal space of chamber 2 from the side surface of chamber 2 toward the central axis 2a of chamber 2. Beam 32b has, for example, a rectangular tubular shape. The internal space of beam 32b is connected to the space outside chamber 2 (atmospheric space) via a hole 32c1 provided in flange 32c.

The flange 32c is attached to the outer wall of the chamber 2. For example, the flange 32c is screwed to the outer wall of the chamber 2. The flange 32c is plate-shaped and has a hole 32c1 that penetrates in the thickness direction.

The cover 33 is provided on the side of the mounting portion 32a opposite to the mounting portion 31. The cover 33 is, for example, screwed to the mounting portion 32a. When the cover 33 is attached to the mounting portion 32a, the hole 32a2 is sealed airtight. The cover 33 is formed from, for example, an aluminum alloy.

As shown in Figure 1, the power supply unit 4 includes, for example, a power supply 41 and a matching unit 42.
The power supply unit 4 is a so-called high-frequency power supply for bias control. In other words, the power supply unit 4 controls the energy of the ions drawn into the workpiece 100 placed on the mounting unit 31.

The power supply 41 outputs high-frequency power having a frequency suitable for attracting ions (for example, a frequency of 27 MHz to 1 MHz).
The matching unit 42 includes, for example, a matching circuit 42a and a fan 42b.
The matching circuit 42a is provided to match the impedance of the power supply 41 side with the impedance of the plasma P side. The matching circuit 42a is electrically connected to the power supply 41 and the electrode 31a via a wiring member (busbar) 42c.
The fan 42b blows air into the support section 32. The fan 42b is provided to cool the wiring member 42c and the matching circuit 42a located inside the support section 32.

In this case, the alignment portion 42 can be provided on the flange 32c of the support portion 32. If the alignment portion 42 is provided on the flange 32c, the mounting module 3 and the alignment portion 42 can be moved together when removing the mounting module 3 from the chamber 2 or attaching the mounting module 3 to the chamber 2. Therefore, maintainability can be improved.

The power supply unit 5 includes electrodes 51, a power supply 52, and a matching circuit 53.
The power supply unit 5 can be a high-frequency power supply for generating plasma P. That is, the power supply unit 5 generates plasma P by creating a high-frequency discharge inside the chamber 2.
In this embodiment, the power supply unit 5 becomes a plasma generation unit that generates plasma P inside the chamber 2.

The electrode 51 is located outside the chamber 2 and is provided above the window 23. The electrode 51 has, for example, a plurality of conductive parts that generate an electromagnetic field and a plurality of capacitive parts (capacitors).
The power supply 52 outputs high-frequency power having a frequency of approximately 100 kHz to 100 MHz. For example, the power supply 52 outputs high-frequency power having a frequency suitable for generating plasma P (for example, a frequency of 13.56 MHz). The power supply 52 may also be capable of changing the frequency of the high-frequency power it outputs.

The matching circuit 53 is provided to match the impedance of the power supply 52 side with the impedance of the plasma P side. The matching circuit 53 is electrically connected to the power supply 52 and the electrode 51 via wiring 54.

The plasma processing apparatus 1 illustrated in Figure 1 is a dual-frequency plasma processing apparatus having an inductively coupled electrode at the top and a capacitively coupled electrode at the bottom. However, the plasma generation method is not limited to the example shown. The plasma processing apparatus 1 may, for example, be a plasma processing apparatus using inductively coupled plasma (ICP) or a plasma processing apparatus using capacitively coupled plasma (CCP).

The pressure reduction unit 6 includes, for example, a pump 61 and a valve 62.
The pressure reduction unit 6 is located below the mounting unit 31 and reduces the pressure so that the inside of the chamber 2 reaches a predetermined pressure.
Pump 61 exhausts the inside of chamber 2 through a hole 21a1 provided in the bottom plate 21a of chamber 2. Pump 61 can be, for example, a turbo molecular pump (TMP). Pump 61 is located outside chamber 2. Pump 61 is connected to a hole 21a1 provided in the bottom plate 21a of chamber 2.

In this case, the central axis of hole 21a1 coincides with the central axis 2a of chamber 2. Therefore, the central axis of the mounting portion 31 provided on the mounting module 3 and the central axis of hole 21a1 provided in the bottom plate 21a of chamber 2 coincide with the central axis 2a of chamber 2. If the central axis of the mounting portion 31 and the central axis of hole 21a1 coincide with the central axis 2a of chamber 2 within the chamber 2, a high effective exhaust velocity and unbiased, axially symmetrical exhaust can be achieved.

Here, when cleaning elements with by-products attached to the inside of chamber 2, or when replacing elements with by-products attached, a so-called atmospheric vent is performed, increasing the internal pressure of chamber 2. Normally, pump 61 is stopped during atmospheric venting. In some cases, a high-speed pump 61 is used to increase the effective pumping speed. A high-speed pump 61 is, for example, a large TMP. In this case, stopping pump 61 takes a considerable amount of time. Furthermore, if pump 61 is stopped, it needs to be restarted after cleaning or element replacement. However, when a high-speed pump 61 is used to increase the effective pumping speed, it may take a considerable amount of time for the pumping speed of the restarted pump 61 to stabilize.

Therefore, in order to keep the pump 61 running during atmospheric venting, the plasma processing device 1 is provided with a valve 62.
The valve 62 has a valve body 62a, an actuation unit 62b, and a sealing member 62c. The valve 62 can be, for example, a so-called poppet valve.
The valve body 62a is plate-shaped and installed inside the chamber 2. The valve body 62a faces the hole 21a1. The planar dimension of the valve body 62a is larger than the planar dimension of the hole 21a1. Therefore, the valve body 62a can open and close the hole 21a1 provided in the bottom plate 21a of the chamber 2. Also, as shown in Figure 1, the planar dimension of the valve body 62a can be the same as or larger than the planar dimension of the mounting part 31. In this way, the planar dimension of the hole 21a1 can be increased, making it easier to achieve a high effective exhaust velocity and axially symmetric exhaust without bias.

The drive unit 62b changes the position of the valve body 62a in the direction of the central axis 2a of the chamber 2. That is, the drive unit 62b raises or lowers the valve body 62a. The drive unit 62b includes, for example, a shaft 62a1 connected to the valve body 62a and a control motor (e.g., a servo motor) that moves the shaft 62a1.

The sealing member 62c is annular in shape and made of an elastic material such as rubber. The sealing member 62c can be, for example, an O-ring. When viewed from a direction along the central axis 2a, the annular sealing member 62c surrounds the hole 21a1 and is located inside the valve body 62a. In Figure 1, the sealing member 62c is shown as being provided on the bottom plate 21a side of the valve body 62a; however, the sealing member 62c may also be provided on the bottom plate 21a.

When the valve body 62a is raised by the drive unit 62b, the hole 21a1 provided in the bottom plate 21a of the chamber 2 is opened. Therefore, the internal space of the chamber 2 and the pump 61 communicate through the hole 21a1.

When the valve body 62a is lowered by the drive unit 62b, the sealing member 62c is sandwiched between the valve body 62a and the bottom plate 21a of the chamber 2. This sandwiching of the sealing member 62c between the valve body 62a and the bottom plate 21a of the chamber 2 closes the hole 21a1 in the bottom plate 21a of the chamber 2, creating an airtight seal. Therefore, communication between the internal space of the chamber 2 and the pump 61 is blocked. As a result, the pump 61 can remain operational during atmospheric venting.

Furthermore, changing the position of the valve body 62a in the direction of the central axis 2a of the chamber 2 changes the distance between the valve body 62a and the bottom plate 21a of the chamber 2. The space between the valve body 62a and the bottom plate 21a of the chamber 2 becomes the exhaust flow path. Therefore, changing the dimensions of this section changes the conductance, allowing control of the exhaust volume and exhaust speed. For example, the controller 8 can control the position of the valve body 62a based on the output of a vacuum gauge (not shown) or similar device that detects the internal pressure of the chamber 2. In other words, if a valve 62 is provided, the exhaust volume and exhaust speed can also be controlled.

The gas supply unit 7 supplies process gas G to the region 21b inside the chamber 2 where plasma P is generated.
The gas supply unit 7 includes, for example, a gas storage unit 71, a gas control unit 72, and an on-off valve 73. The gas storage unit 71, the gas control unit 72, and the on-off valve 73 are located outside the chamber 2.

The gas storage unit 71 stores the process gas G and supplies the stored process gas G into the chamber 2. The gas storage unit 71 can be, for example, a high-pressure cylinder containing the process gas G. The gas storage unit 71 and the gas control unit 72 are connected via piping.

The gas control unit 72 controls the flow rate and pressure when supplying process gas G from the gas storage unit 71 to the chamber 2. The gas control unit 72 can be, for example, a Mass Flow Controller (MFC). The gas control unit 72 and the on-off valve 73 are connected via piping.

The on-off valve 73 is connected via piping to the gas supply port 22b provided in the chamber 2. The on-off valve 73 controls the supply and cessation of process gas G. The on-off valve 73 can be, for example, a two-port solenoid valve. Alternatively, the functions of the on-off valve 73 can be assigned to the gas control unit 72.

The process gas G can be a gas that, when excited and activated by the plasma P, generates desired plasma products (radicals, ions, electrons, etc.). For example, if the plasma treatment is an etching treatment, the process gas G can be a gas that generates plasma products capable of etching the exposed surface of the workpiece 100. In this case, the process gas G can be, for example, a gas containing chlorine, a gas containing fluorine, etc. The process gas G can be, for example, a mixture of chlorine gas and oxygen gas, _CHF3 , a mixture of _CHF3 and _CF4 , a mixture of _SF6 and helium gas, etc. However, the type of process gas G is not limited to those exemplified, and can be appropriately changed depending on the type of plasma treatment and the material of the part of the workpiece 100 being treated.

The controller 8 comprises a processing unit such as a CPU (Central Processing Unit) and a storage unit such as memory. The controller 8 can be, for example, a computer. The controller 8 controls the operation of each element provided in the plasma processing apparatus 1 based on a control program stored in the storage unit.

For example, the controller 8 controls the depressurization unit 6 based on the output of a vacuum gauge (not shown) or other device that detects the internal pressure of the chamber 2, so that the internal pressure of the chamber 2 reaches a predetermined value. The controller 8 also controls the gas supply unit 7 to supply process gas G to the region 21b where plasma P is generated. Furthermore, the controller 8 controls the power supply unit 5 to introduce electromagnetic waves into region 21b. As a result, plasma P is generated in region 21b, and the process gas G is excited and activated by the plasma P, generating reaction products such as ions, electrons, and radicals.

The generated ions and electrons collide with the exposed surface of the workpiece 100, causing the workpiece 100 to be physically treated. In this process, the controller 8 can control the energy of the ions drawn into the workpiece 100 by controlling the power supply unit 4. In addition, the generated radicals come into contact with the exposed surface of the workpiece 100, causing the workpiece 100 to be chemically treated.
Since known techniques can be applied to the control programs that control the operation of each element and to the process conditions, a detailed explanation will be omitted.

Here, depending on process conditions such as processing pressure and the type of process gas G, plasma P may be generated outside of region 21b. For example, plasma P may be generated in the range from region 21b to the vicinity of the valve body 62a of valve 62. Even if plasma P is generated over such a wide range, the generated reaction products are still supplied to the exposed surface of the workpiece 100. Therefore, the workpiece 100 can be subjected to the desired plasma treatment.

However, when plasma P is generated near the valve body 62a, reaction products such as ions, electrons, and radicals are generated in the vicinity of the valve body 62a. As mentioned above, the sealing member 62c is provided on the surface of the valve body 62a facing the bottom plate 21a, or on the bottom plate 21a itself. Therefore, when reaction products are generated near the valve body 62a, these generated reaction products are more likely to reach the sealing member 62c.

In this case, if radicals generated near the valve body 62a come into contact with the sealing member 62c, there is a risk that the sealing member 62c may be damaged by a chemical reaction.

Furthermore, when ions enter the sealing member 62c, the sealing member 62c may be damaged by physical impact. Damage to the sealing member 62c may generate particles, potentially leading to contamination of the processed material 100 by these particles.

Therefore, the plasma processing apparatus 1 is provided with a shielding section 9. As shown in Figure 1, the shielding section 9 is located inside the chamber 2, between the mounting module 3 and the valve 62 (valve body 62a).

The shielding portion 9 is formed from a conductive material such as aluminum alloy or stainless steel. The shielding portion 9 is grounded. As mentioned above, since the chamber 2 is grounded, the shielding portion 9 can be grounded by bringing it into contact with the inner wall of the chamber 2. For example, the peripheral edge of the shielding portion 9 can be connected to the inner wall of the main body portion 21 of the chamber 2, or to the bottom plate 21a of the chamber 2.
If a conductive and grounded shielding portion 9 is provided, ions and radicals incident on the sealing member 62c can be removed by the shielding portion 9.

Furthermore, the shielding portion 9 may be plate-shaped and, for example, be provided parallel to the bottom plate 21a of the chamber 2. The plate-shaped shielding portion 9 may have at least one hole 9a that penetrates in the thickness direction.

As shown in Figure 1, when providing a single hole 9a, the central axis of the hole 9a can be aligned with the central axis 2a of the chamber 2. In this way, unbiased, axially symmetrical exhaust can be achieved.
Furthermore, when providing a single hole 9a, it is preferable that the sealing member 62c be located outside the hole 9a when viewed from a direction along the central axis 2a of the chamber 2. This prevents ions and electrons from reaching the sealing member 62c through the hole 9a.

It is conceivable to provide a shielding section 9 in the space between the mounting module 3 and the inner wall of the main body 21 of the chamber 2. However, since this space is narrow, providing a shielding section 9 in this space would reduce the conductance too much. Therefore, it would be difficult to increase the effective exhaust speed.
In contrast, since there is ample space between the mounting module 3 and the valve 62, even if a shielding section 9 is provided in this space, it is possible to suppress a decrease in conductance. Therefore, it becomes easier to increase the effective exhaust speed.

Furthermore, the shielding portion 9 may be provided with multiple holes, not just one hole 9a.
When multiple holes are provided, it is preferable that the sealing member 62c be located outside the region where the multiple holes are provided, when viewed from a direction along the central axis 2a of the chamber 2. In this way, it is possible to suppress ions and electrons from reaching the sealing member 62c through the multiple holes.

Figures 4(a) and 4(b) are schematic plan views illustrating a case in which a plurality of holes 9a1 to 9a3 are provided in the shielding portion 9.
To avoid complexity, Figure 4 shows the area where the holes in the shielding portion 9 are provided.

As shown in Figures 4(a) and 4(b), there are no particular limitations on the number, shape, or dimensions of the holes. For example, as shown in Figure 4(a), the number, shape, and dimensions of holes 9a1 may differ from those of holes 9a2. As shown in Figure 4(b), multiple identical holes 9a3 may be provided. In this case, it is preferable to make the total area of the multiple holes and the area of a single hole as large as possible. This helps to suppress a decrease in conductance, thereby suppressing a decrease in the effective exhaust velocity.

Furthermore, when providing multiple holes 9a1 to 9a3, it is preferable to provide the holes at point-symmetrical positions around the central axis 2a of the chamber 2, as shown in Figures 4(a) and 4(b). It is also preferable that the shape and dimensions of the holes provided at point-symmetrical positions be the same. This facilitates unbiased, axially symmetrical exhaust.

The embodiments described above are illustrative examples. However, the present invention is not limited to these descriptions.
With respect to the embodiments described above, those modified by those skilled in the art are also included within the scope of the present invention, as long as they retain the features of the present invention.
For example, the shape, material, and arrangement of the components of the plasma processing apparatus 1 are not limited to those exemplified and can be changed as appropriate.
Furthermore, the elements of each embodiment described above can be combined as much as possible, and these combinations are also included within the scope of the present invention insofar as they include the features of the present invention.

1. Plasma processing apparatus, 2. Chamber, 2a. Central axis, 3. Mounting module, 5. Power supply unit, 6. Pressure reduction unit, 7. Gas supply unit, 9. Shielding unit, 9a. Hole, 9a1-9a3. Holes, 21a. Bottom plate, 21a1. Hole, 61. Pump, 62. Valve, 62a. Valve body, 62b. Drive unit, 62c. Seal member, 100. Processed material.

Claims (6)

A chamber capable of maintaining an atmosphere reduced to below atmospheric pressure,
The chamber contains a plasma generating unit capable of generating plasma,
A gas supply unit capable of supplying process gas to the region inside the chamber where the plasma is generated,
A mounting module having a cantilever structure, and capable of supporting a mounting section on which a workpiece is placed below the region where the plasma is generated,
A pump capable of exhausting the inside of the chamber through a hole provided in the bottom plate of the chamber,
A valve body having a plate-like shape and capable of opening and closing the hole provided in the bottom plate of the chamber,
A drive unit capable of changing the position of the valve body in the direction of the central axis of the chamber,
It has an annular shape, and the surface of the valve body on the bottom plate side, or a sealing member provided on the bottom plate,
A shielding portion is provided between the mounting module and the valve body, having at least one hole penetrating in the thickness direction, being conductive and grounded,
A plasma processing device equipped with [unspecified features]. The shielding portion is plate-shaped and is provided parallel to the bottom plate.
The plasma processing apparatus according to claim 1, wherein the central axis of the hole provided in the bottom plate of the chamber coincides with the central axis of the chamber. The plasma processing apparatus according to claim 1 or 2, wherein the shielding portion has one hole, and the central axis of the hole in the shielding portion coincides with the central axis of the chamber. The plasma processing apparatus according to claim 3, wherein, when viewed from a direction along the central axis of the chamber, the sealing member is located outside the hole in the shielding portion. The plasma processing apparatus according to claim 1 or 2, wherein the shielding portion has a plurality of holes, and, when viewed from a direction along the central axis of the chamber, the sealing member is located outside the region of the shielding portion where the plurality of holes are provided. The plasma processing apparatus according to claim 5, wherein the plurality of holes in the shielding portion are provided at point-symmetrical positions with respect to the central axis of the chamber.