TW202127499A - Plasma processing apparatus - Google Patents

Abstract

According to one embodiment, a plasma processing apparatus includes a chamber configured to maintain an atmosphere depressurized below atmospheric pressure, a gas supply part configured to supply a gas into the chamber, a placement part provided inside the chamber, and configured to place a processed product, a depressurization part configured to depressurize inside the chamber, a window provided in the chamber, and facing the placement part, a plasma generator provided outside the chamber and on a surface of the window on an opposite side to the placement part, and configured to generate plasma inside the chamber, an optical path changing part provided inside the window and having a surface tilted to a central axis of the chamber, and a detection part provided on a side surface side of the window, and facing the surface of the optical path changing part.

Description

Plasma processing device

The embodiment of the present invention relates to a plasma processing device.

Plasma processing equipment used in dry etching, etc. is equipped with a detection unit that detects the state of the processed object. For example, in the end point detection of plasma treatment, the end point of the treatment is detected based on the change in the scattering intensity of the light irradiated on the surface of the treatment object. In addition, the endpoint detection of plasma treatment may also detect the endpoint of the treatment based on changes in the luminescence spectrum of the plasma. In addition, the endpoint detection of plasma treatment may also detect the endpoint of the treatment based on the reflected light or transmitted light of the treatment object in the area where it is processed. That is, generally speaking, the end point of plasma treatment is detected based on the optical changes generated during the plasma treatment.

Here, a plasma processing device has been proposed, which includes a detection window (transmission window) provided on the side of the chamber, and a detection unit provided outside the chamber and detecting the luminescence of the plasma through the detection window. In addition, a plasma processing device has been proposed, which is provided with a plate-shaped window provided on the top of the chamber, and a device for detecting light incident from the inside of the chamber to the window and propagated inside the window and emitted from the side of the window Detection department. The detection units detect, for example, light emission in a large area as a whole in the area where the plasma is generated. In this case, since the intensity of the light incident on the detection portion is the average value of the intensity of the light in a wide range, it is difficult to detect slight changes in the surface of the processed object.

In recent years, there has been progress in the miniaturization of the processed parts. For example, the aperture ratio of the unevenness or holes to be formed is also less than 1%. In such a situation, the amount of change in light becomes small because the amount of matter to be removed decreases. Therefore, it is more difficult to detect slight changes in the surface of the processed object if it is to detect light emission in a wide range.

In this case, if the change of light in a narrow area can be detected, the end point of the treatment can be detected with high accuracy even for subtle processing, and even subtle processing can be performed with high accuracy. Therefore, it is desired to develop a plasma processing device that can detect changes in light in a narrow area. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2007-66935 A

[The problem to be solved by the invention]

The problem to be solved by the present invention is to provide a plasma processing device that can detect light changes in a narrow area. [Technical means to solve the problem]

The plasma processing apparatus of the embodiment is provided with: a chamber capable of maintaining a gas environment reduced to a pressure lower than atmospheric pressure; a gas supply part capable of supplying gas to the inside of the chamber; and a mounting part provided in the chamber The inside of the chamber, and the treatment object can be placed; the pressure reducing part, which can decompress the inside of the chamber; the window, which is provided in the chamber and opposite to the placing part; the plasma generating part, which It is provided on the outside of the chamber and on the surface of the window opposite to the side of the placing part, and can generate plasma inside the chamber; the optical path changing part is partially provided inside the window, And it has a surface inclined with respect to the central axis of the chamber; and a detection portion, which is provided on the side surface of the window and faces the surface of the optical path changing portion. [Effects of Invention]

According to the embodiment of the present invention, a plasma processing device capable of detecting light changes in a narrow area can be provided.

Hereinafter, with reference to the drawings, the embodiment will be exemplified. In addition, in each drawing, the same constituent elements are denoted with the same symbols, and detailed descriptions are appropriately omitted. FIG. 1 is a schematic cross-sectional view for illustrating the plasma processing apparatus 1 of this embodiment. FIG. 2 is a schematic perspective view for illustrating the mounting module 3. As shown in Figure 1, in the plasma processing apparatus 1, a chamber 2, a mounting module 3, a power supply unit 4, a power supply unit 5, a pressure reducing unit 6, a gas supply unit 7, a processing state detection unit 8, and And control unit 9.

The chamber 2 may have an airtight structure that can maintain a gas environment decompressed to a pressure lower than the atmospheric pressure. The chamber 2 may have a body part 21, a top plate 22, and a window 23. The main body 21 has a substantially cylindrical shape, and a bottom plate 21a is integrally provided at one end. The other end of the main body 21 is open. The main body 21 may be formed of, for example, metal such as aluminum alloy. In addition, the main body 21 can be grounded. A region 21 b for generating plasma P is provided inside the main body 21. The main body 21 may be provided with a carry-in and carry-in exit 21c for carrying the processed object 100 in and out. The carry-in and carry-out port 21c can be airtightly closed by the gate valve 21c1.

The processed object 100 may be, for example, a photomask, a mask substrate, a wafer, a glass substrate, or the like. However, the treatment object 100 is not limited to the exemplified one.

The top plate 22 may have a plate shape and is arranged in a manner of covering the opening of the main body 21. The top plate 22 may be disposed opposite to the bottom plate 21a. A hole 22a penetrating the thickness direction can be provided in the central area of the top plate 22. The center of the hole 22a can be set on the central axis 2a of the chamber 2 (the body part 21). The hole 22a may be provided for transmitting the electromagnetic wave radiated from the electrode 51 described later through 2.14/4. The top plate 22 may be formed of, for example, metal such as aluminum alloy.

The window 23 may have a plate shape and is provided on the top plate 22. The window 23 can be provided in such a way as to cover the hole 22a. That is, the window 23 is provided in the chamber 2 and faces the placing portion 31. The window 23 can transmit light and electromagnetic fields, and can be formed of a material that is not easily etched during etching. The window 23 may be formed of, for example, a dielectric material such as quartz.

As shown in FIGS. 1 and 2, the mounting module 3 may have a mounting portion 31, a supporting portion 32, and a cover 33. The mounting module 3 may have a cantilever structure that protrudes from the side surface of the chamber 2 (the body part 21) into the chamber 2 (the body part 21), and the mounting part 31 is provided on the front end side. The processed object 100 can be placed on the placing part 31. The placing portion 31 is located below the region 21b where the plasma P is generated.

The mounting part 31 may have an electrode 31a, an insulating ring 31b, and a pedestal 31c. The electrode 31a may be formed of a conductive material such as metal. The upper surface of the electrode 31a may be a mounting surface for mounting the processed object 100. The electrode 31a can be fastened to the base 31c with screws, for example. In addition, the electrode 31a may incorporate a pickup pin 31a1 (refer to FIG. 2), a temperature control unit, and the like. Plural picking pins 31a1 can be provided.

Plural pick-up pins 31a1 can be rod-shaped, and can be set to protrude from the upper surface of the electrode 31a. The plural pick-up pins 31a1 can be used when the processing object 100 is transferred. Therefore, the plurality of pick-up pins 31a1 can be protruded from the upper surface of the electrode 31a and retracted into the electrode 31a by a driving part not shown. The number or arrangement of the plural pick-up pins 31a1 can be appropriately changed according to the size or top view shape of the processed object 100.

The temperature control unit may be, for example, a circulation circuit (flow path) of a refrigerant, a heater, or the like. The temperature control unit can control the temperature of the electrode 31a and the temperature of the processing object 100 placed on the electrode 31a based on the output from a temperature sensor not shown, for example.

The insulating ring 31b may have a ring shape and cover the side surface of the electrode 31a. The insulating ring 31b may be formed of, for example, a dielectric material such as quartz. The pedestal 31c can be provided between the electrode 31a and the mounting portion 32a of the support portion 32. The pedestal 31c may be provided to insulate the electrode 31a from the supporting portion 32. The pedestal 31c may be formed of, for example, a dielectric material such as quartz. The base 31c can be fastened to the mounting portion 32a of the support portion 32 with screws, for example.

The supporting part 32 can support the placing part 31 in the inner space of the chamber 2. The supporting portion 32 may be one extending between the side surface of the cavity 2 and the lower portion of the placing portion 31. The support portion 32 may have a mounting portion 32a, a beam 32b, and a flange 32c. The mounting portion 32a, the beam 32b, and the flange 32c may be formed of aluminum alloy or the like, for example.

The mounting portion 32a may be located below the placing portion 31 in the internal space of the chamber 2. The mounting portion 32a can be arranged such that the center of the mounting portion 32a is located on the central axis 2a of the chamber 2. The mounting portion 32a may have a cylindrical shape, and a hole 32a1 is provided on the end surface of the placing portion 31 side. A hole 32a2 can be provided on the end surface on the opposite side to the placing portion 31 side. The bus bar 42c, pipes for refrigerant, etc. can be connected to the electrode 31a through the hole 32a1.

The hole 32a2 can be used for connecting the bus bar 42c, pipes for refrigerant, etc., or for maintenance of the electrode 31a. The mounting part 31 (pedestal 31c) can be provided on the end surface of the mounting part 31 side of the mounting part 32a. Therefore, the planar shape of the mounting portion 32a can be the same as the planar shape of the placing portion 31. The plan size of the mounting portion 32a may be the same as or slightly larger than the plan size of the placing portion 31.

One end of the beam 32b can be connected to the side surface of the mounting portion 32a. The other end of the beam 32b can be connected to the flange 32c. The beam 32b may extend from the side surface of the chamber 2 to the central axis 2a of the chamber 2 in the internal space of the chamber 2. The beam 32b may be in the shape of an angular cylinder. The internal space of the beam 32b can be connected to the space (atmospheric space) outside the chamber 2 through the hole 32c1 provided in the flange 32c. Therefore, the bus bar 42c can be connected to the atmospheric space. If the internal space of the beam 32b is connected to the external space of the chamber 2, the pressure of the internal space of the beam 32b is the same as the pressure of the external space of the chamber 2 (for example, atmospheric pressure). In addition, the internal space of the beam 32b may be connected to the internal space of the mounting portion 32a. In this case, the pressure of the internal space of the support portion 32 is the same as the pressure of the external space of the chamber 2 (for example, atmospheric pressure).

The flange 32c may have a plate shape and have a hole 32c1 penetrating through the thickness direction. The flange 32c can be installed on the outer side wall of the chamber 2, for example, can be fastened to the outer side wall of the chamber 2 with screws.

A hole 2b can be provided on the side of the chamber 2. The hole 2b may have a size and shape that can pass through the placing portion 31 installed on the mounting portion 32a. Therefore, the mounting module 3 provided with the mounting part 31 can be detached from the chamber 2 through the hole 2b, or the mounting module 3 provided with the mounting part 31 can be mounted in the chamber 2.

That is, through the hole 2b, the mounting portion 32a and the beam 32b provided with the mounting portion 31 can be carried into the inside of the chamber 2 and carried out to the outside of the chamber 2. In addition, in order to easily install and remove the mounting module 3, a sliding member may be provided on the outer side wall of the chamber 2.

The cover 33 may be provided on the end surface of the mounting portion 32a on the opposite side to the placing portion 31 side. The cover 33 can be fastened to the mounting portion 32a with screws, for example. By mounting the cover 33 on the mounting portion 32a, the hole 32a2 can be airtightly closed. The shape of the cover 33 is not particularly limited, and it may be a dome-shaped cover 33 or a plate-shaped cover 33. The cover 33 may be formed of, for example, aluminum alloy or the like.

Here, if it is the support portion 32 having a cantilever structure, a space can be provided below the placement portion 31 in the internal space of the chamber 2, so the decompression portion 6 can be placed directly below the placement portion 31. If the decompression part 6 can be arranged directly below the mounting part 31, the effective exhaust speed will be increased, and it will be easy to perform axisymmetric exhaust without shifting. In addition, if it is the support part 32 with a cantilever structure, the support part 32 provided with the placing part 31 can be detached from the chamber 2 from the horizontal direction, or the support part 32 provided with the placing part 31 can be installed in the chamber 2. Therefore, the maintenance of the plasma processing apparatus becomes easier compared with the case where the placing part is fixed to the bottom surface of the chamber 2.

However, the mounting portion 31 is provided with a metal electrode 31a. In addition, the mounting portion 31 is also provided with a pickup pin 31a1 or its driving portion, a cooling medium circulation line, a temperature control portion such as a heater, and the like. Therefore, the weight of the placing portion 31 becomes heavier. Since the support portion 32 has a cantilever structure, if the weight of the placement portion 31 provided on the front end side becomes heavier, the load will shift, and the front end of the beam 32b that supports the placement portion 31 may bend downward. If the front end of the beam 32b is bent downward, there is a concern that the placement portion 31 may incline. For example, the weight of the placing portion 31 may be 56 to 70 kgf (weight kilogram). In this case, the front end of the mounting module 3 may drop about 0.2 mm downward.

Since the processing object 100 is placed on the placing portion 31, the placing surface on which the processing object 100 is placed must have an area that is at least the area of the main surface of the processing object 100. Therefore, the size of the placing portion 31 in plan view becomes larger. If the placement portion 31 with a large size in a plan view is inclined, the gas flow in the chamber 2 will become chaotic, or the plasma density will become uneven, and there may be concerns about uneven processing characteristics.

In this case, if the cross-sectional size of the beam 32b supporting the placement portion 31 is increased in order to suppress the inclination of the placement portion 31, it may hinder the exhaust gas and reduce the effective exhaust velocity, or the axis symmetry without deviation Doubts that exhaust becomes difficult. In this case, if a plurality of beams 32b supporting the placement portion 31 are provided, the cross-sectional size of one beam 32b can be reduced, so that the reduction in the effective exhaust speed can be suppressed. In addition, as long as a plurality of beams 32b are arranged, the axisymmetric exhaust can still be performed. However, arranging a plurality of beams 32b will increase the size of the part fixed to the side of the chamber 2, which may make the mounting and dismounting of the support part 32 difficult, and there is a concern that the maintainability will be reduced.

In response to this, the supporting portion 32 of the present embodiment is provided with a beam 32b having a space inside. And, as mentioned above, the internal space of the beam 32b is connected to the external space of the chamber 2. That is, the pressure of the internal space of the beam 32b is the same as the pressure of the external space of the chamber 2 (for example, atmospheric pressure). In addition, the wall thickness of the side (upper side) of the beam 32b on the side of the placing portion 31 is set to t1, and the side of the beam 32b and the side of the placing portion 31 on the opposite side (the lower side) When the wall thickness is set to t2, "t1>t2".

Therefore, when the plasma treatment is performed, an equal distributed load corresponding to the difference between the internal pressure of the beam 32b and the external pressure of the beam 32b is applied to the upper side and the lower side of the beam 32b. In this case, the equal distributed load applied to the side portion on the upper side and the side portion on the lower side of the beam 32b is equal. Therefore, if "t1>t2", the bending amount of the side portion on the upper side of the beam 32b is greater than the bending amount of the side portion on the lower side of the beam 32b. As a result, the front end of the beam 32b bends upward, so the upward bending caused by the pressure difference can be used to offset the downward bending caused by the weight of the placing portion 31. In addition, the specific dimensions of the wall thickness t1 and t2 can be appropriately determined through experiments or simulations.

Next, returning to FIG. 1, the power supply unit 4, the power supply unit 5, the pressure reducing unit 6, the gas supply unit 7, the processing state detection unit 8, and the control unit 9 will be described. The power supply unit 4 may be a so-called high-frequency power supply for bias control. That is, the power supply unit 4 may be provided for controlling the ion energy of the processing object 100 introduced onto the placing unit 31.

The power supply unit 4 may have a power supply 41 and a matching unit 42. The power supply 41 can output high frequency power having a frequency suitable for introducing ions (for example, a frequency of 1 MHz to 27 MHz). The matching part 42 may have a matching circuit 42a, a fan 42b, and a bus 42c. The matching circuit 42a may be provided for matching between the impedance on the power source 41 side and the impedance on the plasma P side. The matching circuit 42a can be electrically connected to the power source 41 and the electrode 31a via a bus bar (wiring member) 42c. That is, the power source 41 can be electrically connected to the electrode 31a provided on the mounting portion 31 via the bus bar 42c. The fan 42b can convey air inside the support part 32. The fan 42b may be provided for cooling the bus bar 42c or the matching circuit 42a provided inside the support portion 32.

In addition, the matching portion 42 may be provided on the flange 32c of the supporting portion 32. If the matching portion 42 is provided on the flange 32c, when the mounting module 3 is detached from the chamber 2 (body part 21), or the mounting module 3 is installed in the chamber 2 (body part 21), The mounting module 3 and the matching portion 42 are moved integrally. Therefore, the maintainability can be improved. In addition, the internal space of the beam 32b is connected to the external space of the chamber 2 (the main body 21) via the matching portion 42. Therefore, the pressure of the internal space of the beam 32b can be set to be the same as the pressure of the external space of the chamber 2 (for example, atmospheric pressure).

The power supply unit 5 may be a high-frequency power supply for generating plasma P. That is, the power supply unit 5 may be provided to generate a high-frequency discharge inside the chamber 2 to generate plasma P. In this embodiment, the power supply part 5 is provided on the outside of the chamber 2 and the window 23 is on the opposite side of the mounting part 31 side, and is a plasma generating part that generates plasma P inside the chamber 2 .

The power supply part 5 may have an electrode 51, a power supply 52, a matching circuit 53, and a Faraday shield 54. The electrode 51 may be provided outside the chamber 2 and above the window 23. The electrode 51 may have a plurality of conductor parts and a plurality of capacitor parts (capacitors) for generating an electromagnetic field. The power supply 52 can output high frequency power with a frequency of about 100 KHz to 100 MHz. In this case, the power supply 52 can output high frequency power having a frequency suitable for generating plasma P (for example, a frequency of 13.56 MHz). In addition, the power source 52 may also be one that changes the frequency of the output high-frequency power.

The matching circuit 53 may be provided for matching between the impedance of the power source 52 and the impedance of the plasma P. The matching circuit 53 can be electrically connected to the power source 52 and the electrode 51 via the wiring 55. The matching circuit 53 may also be electrically connected to the power source 52 and the electrode 51 via a bus bar.

The Faraday shield 54 may be provided between the window 23 and the electrode 51. The Faraday shield 54 may have a plate shape and be formed of a conductive material such as metal. The Faraday shield 54 may have a plurality of slits extending radially from the center. In addition, an insulating film using an insulating material can be provided on the surface of the Faraday shield 54 on the electrode 51 side. The portion of the Faraday shield 54 formed of a conductive material can be grounded.

In addition, the plasma processing device 1 illustrated in FIG. 1 is a dual-frequency plasma processing device having an inductive coupling type electrode at the upper part and a capacitive coupling type electrode at the bottom. However, the method of generating plasma is not limited to those exemplified. The plasma processing device 1 may be, for example, a plasma processing device using inductively coupled plasma (ICP: Inductively Coupled Plasma) or a plasma processing device using capacitively coupled plasma (CCP: Capacitively Coupled Plasma).

The decompression part 6 may be located below the placing part 31, and the pressure may be reduced in such a way that the inside of the chamber 2 becomes a specific pressure. The pressure reducing part 6 may have a pump 61 and a valve 62. The pump 61 may be provided outside the chamber 2. The pump 61 can be connected to the hole 21a1 provided in the bottom plate 21a of the chamber 2. The pump 61 can discharge the gas inside the chamber 2. The pump 61 may be, for example, a turbo molecular pump (TMP: Turbo Molecular Pump) or the like. In addition, as a reverse pump, a Roots-type dry pump can also be connected to a turbomolecular pump.

The valve 62 may have a valve body 62a and a driving part 62b. The valve body 62a may be plate-shaped and arranged inside the chamber 2. The valve body 62a can face the hole 21a1. The top view size of the valve body 62a may be larger than the top view size of the suction port 61a. When viewing the valve body 62a from the direction of the central axis 2a, the valve body 62a can cover the suction port 61a of the pump 61.

The driving portion 62b can change the position of the valve body 62a in the direction of the center axis 2a of the chamber 2 (body portion 21). That is, the driving portion 62b can raise the valve body 62a or lower the valve body 62a. The driving portion 62b may include a shaft 62a1 connected to the valve body 62a, and a control motor (for example, a servo motor, etc.) that moves the shaft 62a1. The valve 62 may be a so-called poppet valve.

Here, if the position of the valve body 62a changes inside the chamber 2, the distance between the valve body 62a and the bottom plate 21a of the chamber 2 changes. The space between the valve body 62a and the bottom plate 21a of the chamber 2 becomes a flow path for exhaust. Therefore, if the size of this part is changed, the conductance will change, so the exhaust volume or exhaust speed can be controlled. The control part 9 can control the drive part 62b based on the output of the vacuum gauge etc. which are not shown in figure which detects the internal pressure of the chamber 2, and can change the position of the valve body 62a, for example. In addition, the vacuum gauge may be a diaphragm type capacitance pressure gauge or the like.

The gas supply part 7 can supply the gas G to the region 21 b in the chamber 2 where the plasma P is generated. The gas supply unit 7 may include a gas storage unit 71, a gas control unit 72, and an on-off valve 73. The gas storage part 71, the gas control part 72, and the on-off valve 73 may be provided outside the chamber 2. The gas accommodating part 71 can accommodate the gas G, and supply the accommodated gas G to the inside of the chamber 2. The gas storage portion 71 may be, for example, a high-pressure bottle that stores gas G, or the like. The gas storage unit 71 and the gas control unit 72 may be connected via pipes.

The gas control unit 72 can control the flow rate, pressure, etc. of the gas G supplied from the gas storage unit 71 to the inside of the chamber 2. The gas control unit 72 may be, for example, an MFC (Mass Flow Controller) or the like. The gas control unit 72 and the on-off valve 73 can be connected via pipes.

The on-off valve 73 can be connected to the gas supply port 22b provided in the chamber 2 via a pipe. In addition, a plurality of gas supply ports 22b may be provided, and the gas G may be evenly supplied to the region 21b where the plasma P is generated from a plurality of directions. The on-off valve 73 can control the supply and stop of the gas G. The on-off valve 73 may be, for example, a two-way solenoid valve or the like. In addition, the gas control unit 72 may have the function of opening and closing the valve 73.

The gas G can be one that generates desired radicals or ions when excited and activated by the plasma P. For example, if the plasma treatment is an etching treatment, the gas G may be one that generates radicals or ions that can etch the exposed surface of the treatment object 100. In this case, the gas G may be, for example, a gas containing chlorine, a gas containing fluorine, or the like. The gas G can be, for example, a mixed gas of chlorine and oxygen, CHF ₃ , a _{mixed gas of CHF 3} and CF ₄ , a mixed gas of SF ₆ and helium, and the like.

The processing state detection unit 8 can detect the state of the processing object 100 based on the optical change generated during the plasma processing. For example, the processing state detection unit 8 can perform end-point detection of plasma processing. The processing state detection unit 8 may include an optical path changing unit 81 and a detection unit 82.

The light path changing part 81 may be provided inside the window 23. The light path changing section 81 is in the direction from the window 23 to the placement section 31 (the thickness direction of the window 23), and the direction orthogonal to the direction from the window 23 to the placement section 31 (orthogonal to the thickness direction of the window 23). Direction), change the light path of the incident light. For example, the light path changing portion 81 may be partially provided inside the window 23 and have a surface (reflecting surface) that is inclined with respect to the central axis 2a of the chamber 2.

FIG. 3 is a schematic cross-sectional view for illustrating the light path changing part 81. The light path changing portion 81 illustrated in FIG. 3 may be a recessed portion opened on the surface of the window 23 opposite to the placing portion 31 side. For example, the bottom surface of the recessed portion of the optical path changing portion 81 is a flat surface, and the bottom surface is a surface 81a that is a reflective surface. The angle between the surface 81a and the central axis 2a of the chamber 2 can be set to 45°. The outer shape of the recess may be, for example, a cylinder or a polygonal column.

As shown in FIG. 3, the optical path changing unit 81 can reflect the incident light La and make the angle between the optical path of the incident light La and the optical path of the outgoing light Lb 90°. That is, the incident angle of the light from the detecting portion 82 toward the surface 81a to the surface 81a can be set to 45°, and the reflection angle can be set to 45°. In addition, FIG. 3 illustrates a case where light enters from the thickness direction of the window 23 (a case where light enters from the side of the mounting portion 31 to the optical path changing portion 81). However, if the inspection light enters from the side (peripheral end) side of the window 23 In the case of the light path changing part 81, the light path changing part 81 also changes the traveling direction of the inspection light. In addition, the inspection light emitted from the optical path changing section 81 and reflected by the processed object 100 is also the same as the incident light La, and the traveling direction of the inspection light is changed by the optical path changing section 81.

The optical path changing portion 81 illustrated in FIG. 3 is a concave portion as described above. The inside of the light path changing part 81 may be a space, and may also be filled with gas, liquid, or solid. In addition, a film containing a material with higher reflectivity (for example, a film containing titanium oxide) may be formed on the surface 81a. When gas, liquid, or solid is filled in the light path changing portion 81, or a film is provided on the surface 81a, it is preferable to use an insulating gas, liquid, or solid. In this way, the influence of the optical path changing portion 81 on the electromagnetic field formed by the power supply portion 5 can be suppressed. In addition, if the surface 81a has irregularities, light will be scattered due to the irregularities, so it is preferable to increase the flatness of the surface 81a. For example, the surface roughness of the surface 81a can be set to Ra0.02 or less by optical polishing.

4(a) and (b) are schematic cross-sectional views for illustrating a modification example of the optical path changing part. As shown in FIG. 4(a), it may be an optical path changing portion 81b with a smaller depth dimension d. If the depth dimension d is small, the length of the cutting tool used for cutting the optical path changing portion 81b, that is, the concave portion can be shortened. The shorter the length of the cutting tool, the more rigid the cutting tool can be improved. Therefore, the vibration of the cutting tool is reduced, and the flatness of the bottom surface (surface 81ba) of the optical path changing portion 81b, that is, the recessed portion is improved. For example, if the surface 81ba is a circle, the depth dimension d is preferably 0.5 times or more and 1.0 times the diameter of the circle. In addition, if the surface 81ba is a quadrilateral, the depth dimension d is preferably 0.5 to 1.0 times the diameter of the inscribed circle of the quadrilateral.

In addition, as shown in FIG. 4(b), it may be an optical path changing portion 81c having a large area of the bottom surface (surface 81ca). By increasing the area of the surface 81ca, a cutting tool with a larger cross-sectional area can be used. The larger the cross-sectional area of the cutting tool, the more rigid the cutting tool can be improved. Therefore, the vibration of the cutting tool is reduced, and the flatness of the bottom surface (surface 81ca) of the optical path changing portion 81c, that is, the recessed portion is improved. In addition, it is also possible to reduce the depth of the concave portion and increase the area of the bottom surface of the concave portion. This can further improve the flatness of the bottom surface. In addition, since optical polishing is easy to perform, it is easier to make the flatness of the bottom surface a desired value.

Here, the cross-sectional area of the light path changing portion 81 in the direction orthogonal to the central axis 2a (refer to "D" in FIG. 6) is preferably the area of the surface on the side opposite to the placement portion 31 of the window 23 1.95% or less. Alternatively, the load of the light path changing portion 81 is preferably 9.8% or less of the allowable load of the window 23. If the load applied to the light path changing portion 81 is at this level, the durability of the window 23 with the light path changing portion 81 can be regarded as substantially the same as the durability of the window without the light path changing portion 81. That is, in this way, the strength (vacuum resistance strength) of the window 23 can be maintained.

In addition, the cross-sectional area of the light path changing portion 81 in the direction orthogonal to the central axis 2a (refer to "D" in FIG. 6) is more preferably 0.5 of the area of the surface on the side opposite to the placement portion 31 of the window 23 %the following. Alternatively, the load applied to the light path changing portion 81 is more preferably 5.0% or less of the allowable load of the window 23. In this way, the electrostatic capacitance of the window 23 can be changed slightly, so that the influence of the optical path changing portion 81 on the electromagnetic field formed by the power supply portion 5 can be suppressed.

Fig. 5 is a schematic cross-sectional view for illustrating another modification of the optical path changing portion. The light path changing portion 81d illustrated in FIG. 5 is a concave portion having a polygonal column shape (for example, a quadrangular column shape) having a flat side surface 81da. The side surface 81da of the light path changing portion 81d is inclined at an angle of 45° with respect to the upper surface of the window 23 (the surface on the opposite side to the placing portion 31 side). In this way, the incident light La incident from the direction orthogonal to the upper surface of the window 23 toward the side 81da becomes the outgoing light Lb reflected in the direction parallel to the upper surface of the window 23. In this case, since the area of the side surface of the recess can be easily increased compared to the bottom surface of the recess, it is easy to perform optical polishing.

Here, a part of the light incident from the side of the placement portion 31 of the window 23 toward the inside of the window 23 is reflected inside the window 23 and emitted from the side surface (peripheral end surface) of the window 23 to the outside. Therefore, the light emitted from the side of the window 23 to the outside can also be detected by the detection unit 82. However, if this is the case, the intensity of the light incident on the detection portion 82 becomes the average value of the intensity of the light in a wider range, so it is difficult to detect slight changes in the surface of the processed object 100.

In recent years, there has been progress in the miniaturization of processed parts. For example, the aperture ratio of the unevenness or holes to be formed has become less than 1%. In this case, since the amount of matter to be removed decreases, the amount of light change becomes small. Therefore, it is more difficult to detect slight changes in the surface of the processed object 100 if it is to detect light emission in a wide range.

Moreover, as described above, the electrode 51 or the Faraday shield 54 and the like are provided on the window 23. Therefore, if the light emitted in the thickness direction of the window 23 is detected, it may be hindered by the electrode 51, the Faraday shield 54 or the like, and the light at the proper position may not be detected.

As described above, the light path changing part 81 can reduce the cross-sectional area and can be provided at any position of the window 23. Therefore, it is possible to detect light changes in a narrow area (detection area) at an appropriate position. As a result, even with fine processing, the end point of plasma processing can be detected with high accuracy, and even fine processing can be performed with high accuracy.

In addition, since the angle between the optical path of the incident light and the optical path of the emitted light can be made 90°, the detection portion 82 can be arranged on the side surface of the window 23. Therefore, regardless of the shape or arrangement of the electrode 51 or the Faraday shield 54 or the like, the detection portion 82 can be arranged at an appropriate position.

The detection part 82 may be provided on the side surface of the window 23 and at a position opposite to the surface 81 a of the light path changing part 81. If the optical path changing part 81 is provided, a part of the light generated inside the chamber 2 is reflected on the surface 81 a of the optical path changing part 81 and enters the detection part 82. Therefore, the detection part 82 may have a light-receiving part. For example, the detection unit 82 can detect the state of the processed object 100 (for example, the end point of plasma processing) based on the change in the wavelength of the light incident to the light receiving unit via the optical path changing unit 81.

In addition, "the position opposite to the surface 81a of the optical path changing portion 81" means that the detection portion 82 can detect the light (incident light La) incident from the surface of the placement portion 31 of the window 23 into the interior of the window 23. The position of the light (outgoing light Lb) reflected by the surface 81a of the optical path changing portion 81.

Also, for example, the detection unit 82 may have a light projecting unit and a light receiving unit. The light projecting unit can irradiate inspection light on the surface of the processing object 100 via the light path changing unit 81. The light-receiving part can receive the interference light of the light reflected by the surface of the processing object 100 and going to the light-receiving part via the optical path change part 81, and the light emitted from the light-projecting part. For example, the detection unit 82 irradiates the surface of the processing object 100 with light via the surface 81 a of the optical path changing unit 81. The light reflected by the surface of the processed object 100 and further reflected by the surface 81 a of the light path changing portion 81 is incident on the detecting portion 82. In this case, the detection unit 82 can detect the state of the processed object 100 (for example, the end point of plasma processing) based on the change of the interference light.

In addition, the detection part 82 is not limited to what is illustrated, and what is necessary is just to detect an optical change. For example, the detection unit 82 may further have a spectroscope. If a beam splitter is provided, light with a specific wavelength can be captured, so the detection accuracy can be improved.

In addition, if there is a detection part 82 of the light-emitting part and the light-receiving part, it is preferable that most of the light reflected from the surface of the processed object 100 enters the surface 81a of the optical path changing part 81. That is, it is preferable that the optical axis of the inspection light bent by the optical path changing portion 81 is substantially the same as the optical axis of the inspection light reflected from the surface of the processing object 100. For this reason, the window 23 and the placing portion 31 are preferably substantially parallel. However, as described above, in the case where the support portion 32 supporting the placement portion 31 has a cantilever structure, there is a concern that the placement portion 31 may incline. Therefore, in the case of using the detecting portion 82 with the light-emitting portion and the light-receiving portion, and the mounting portion 31 with a cantilever structure, it is preferable that the wall thickness (t1) of the upper side of the beam 32b is thicker than the lower side of the beam 32b The thickness of the side wall (t2) (t1>t2). If "t1>t2", it is easy to make the window 23 and the placing part 31 approximately parallel, so the optical axis of the inspection light bent by the optical path changing part 81 and the light of the inspection light reflected from the surface of the processing object 100 can be made The axes are roughly the same.

In addition, as shown in FIG. 1, the optical path changing unit 81 and the detecting unit 82 may be connected via the light guide unit 83. In this case, the light guide portion 83 faces the surface 81 a of the light path changing portion 81. The light guide 83 may be, for example, an optical fiber or the like. The light guide portion 83 is not necessary, and the detection portion 82 may be provided close to the side surface of the window 23. However, if the light guide portion 83 is provided, it is easy to install the detection portion 82 at a desired position.

Fig. 6 is a schematic plan view for illustrating the flat surface provided on the side surface of the window. As shown in FIG. 6, a flat surface 23 a may be provided on a portion of the side surface of the window 23 opposite to the detection portion 82 or the light guide portion 83. When the light guide portion 83 is provided, the light guide portion 83 may be provided between the side surface 23 a of the window 23 and the detection portion 82. In this way, the optical connection between the detection portion 82 or the light guide portion 83 and the window 23 can be easily performed.

In addition, if the surface 23a has irregularities, light will be scattered due to the irregularities, so it is preferable to increase the flatness of the surface 23a in the same way as the surface 81a. For example, the surface roughness of the surface 23a can be set to Ra0.02 or less by optical polishing. In addition, on a straight line 2c orthogonal to the axis 2a and intersecting the axis 2a, there are the center of the surface 23a and the center of the surface 81a. In addition, the surface 23a is orthogonal to the straight line 2c, and the surface 81a can be set to pass through the center of the surface 81a, and the straight line B along the surface 81a may be orthogonal to the straight line 2c. By arranging the detecting part 82 or the light guiding part 83 so that the optical axis of the inspection light emitted from the detecting part 82 or the light guiding part 83 coincides with the straight line 2c, the detecting part 82 or the light guiding part 83 can be easily connected to the optical path. The optical connection of the changing part 81. Moreover, as long as the surface 81a is provided directly above the position where the processing state of the processing object 100 is to be detected, the processing state of the processing object 100 can be reliably detected at the desired position.

In addition, the light guide portion 83 may have a plurality of optical fibers. The detection part 82 may have a plurality of spectroscopes. In addition, one optical fiber can be connected to one splitter. In this way, the aforementioned interference light detection can be easily performed.

In addition, the optical path changing unit 81 may be provided in plural. If a plurality of light path changing units 81 are provided, the processing state of the plurality of parts can be known. Moreover, if the optical path changing unit 81 for detection is selected, the processing status of a plurality of parts can be obtained without increasing the number of the detection units 82.

The control unit 9 may be a computing unit such as a CPU (Central Processing Unit) and a storage unit such as a memory. The control unit 9 can control the actions of various elements provided in the plasma processing apparatus 1 based on a control program stored in the memory unit. For example, the control unit 9 may end the plasma processing based on the output from the processing state detection unit 8 (detection unit 82).

7(a) and (b) are schematic cross-sectional views for illustrating another embodiment of the light path changing part 181. As shown in FIG. 7(a) and (b), the light path changing part 181 may be provided inside the window 23. The light path changing portion 181 may have a flat end surface 181a, and the angle between the end surface 181a and the central axis 2a of the chamber 2 is 45°.

As shown in FIG. 7(a), the light path changing portion 181 can be embedded in the window 23. For example, the light path changing part 181 may be embedded when the window 23 is formed. For example, the inside of the window 23 can be processed by irradiating a laser on the window 23 to form the optical path changing part 181.

As shown in FIG. 7(b), a concave portion 181b may be provided in the window 23, and a light path changing portion 181 may be provided inside the concave portion 181b. The optical path changing portion 181 is preferably formed of a material with high reflectivity and insulation. For example, the light path changing part 181 may be a processed interior of the window 23, a titanium oxide-containing film, or the like. If the optical path changing part 181 is insulated, the influence of the optical path changing part 181 on the electromagnetic field formed by the power supply part 5 can be suppressed.

FIG. 8 is a schematic cross-sectional view for illustrating a plasma processing apparatus 101 according to another embodiment. As shown in FIG. 8, a chamber 102, a mounting portion 103, a power supply unit 4, a power supply unit 5, a decompression unit 106, a gas supply unit 7, a processing state detection unit 8, and a control unit can be provided in the plasma processing apparatus 101 109. In addition, also in the plasma processing apparatus 101, the power supply unit 5 is a plasma generating unit that generates plasma P inside the chamber 102.

The chamber 102 may have an airtight structure that can maintain a gas environment decompressed to a pressure lower than the atmospheric pressure. The chamber 102 may have a body portion 102 a and a window 23. The main body 102a may be formed by integrating a top plate, a bottom plate, and a substantially cylindrical side part. The main body 102a may be formed of, for example, metal such as aluminum alloy. In addition, the main body 102a can be grounded. A region 102b for generating plasma P is provided inside the main body 102a. The main body part 102a may be provided with a loading and unloading outlet 102c for loading and unloading the processed object 100. The loading/unloading port 102c can be airtightly closed by the gate valve 102d.

The placing portion 103 may be provided inside the cavity 102 (the body portion 102a) and on the bottom surface of the body portion 102a. The mounting part 103 may have an electrode 103a, a pedestal 103b, and an insulating ring 103c. The inside of the placing part 103 can be connected to an outside space (atmospheric space).

The electrode 103a may be provided under the region 102b where the plasma P is generated. The upper surface of the electrode 103a may be a mounting surface for mounting the processed object 100. The electrode 103a may be formed of a conductive material such as metal. Also, like the electrode 31a described above, a plurality of pick-up pins, temperature control parts, etc. can be built into the electrode 103a.

The pedestal 103b may be provided between the electrode 103a and the bottom surface of the main body 102a. The pedestal 103b may be provided to insulate the electrode 103a from the main body 102a. The pedestal 103b may be formed of, for example, a dielectric material such as quartz.

The insulating ring 103c may have a ring shape and is arranged to cover the side surface of the electrode 103a and the side surface of the pedestal 103b. The insulating ring 103c may be formed of, for example, a dielectric material such as quartz.

The plasma processing apparatus 101 of this embodiment may also be provided with the power supply unit 4 described above. As described above, the power supply unit 4 may be a so-called high-frequency power supply for bias control. In addition, the matching circuit 42a can be electrically connected to the power source 41 and the electrode 103a via the bus 42c. Since the inside of the placing portion 103 is connected to the air space, the bus bar 42c can be connected to the air space.

The plasma processing device 101 can also be a dual-frequency plasma etching device with an inductive coupling type electrode on the upper part and a capacitive coupling type electrode on the lower part. However, the method of generating plasma is not limited to those exemplified. The plasma processing device 101 may be, for example, a plasma processing device using inductively coupled plasma (ICP: Inductively Coupled Plasma) or a plasma processing device using capacitively coupled plasma (CCP: Capacitively Coupled Plasma).

The pressure reducing unit 106 may include a pump 106a and a pressure control unit 106b. The decompression part 106 can depressurize so that the inside of the chamber 102 becomes a specific pressure. The pump 106a may be, for example, a turbomolecular pump or the like. In addition, as a reverse pump, a Roots-type dry pump can also be connected to a turbomolecular pump. The pump 106a and the pressure control unit 106b can be connected via a pipe.

The pressure control unit 106b can perform control such that the internal pressure of the chamber 102 becomes a specific pressure based on the output of a vacuum gauge (not shown) that detects the internal pressure of the chamber 102. In addition, the vacuum gauge may be a diaphragm type capacitance pressure gauge or the like. The pressure control unit 106b may be, for example, APC (Auto Pressure Controller) or the like. The pressure control part 106b can be connected to the exhaust port 102e provided in the main body part 102a via a pipe.

The control unit 109 may be a computing unit such as a CPU or a storage unit such as a memory. The control unit 109 can control the actions of various elements provided in the plasma processing apparatus 101 based on the control program stored in the memory unit. For example, the control unit 109 may end the plasma processing based on the output from the processing state detection unit 8 (detection unit 82). Since the plasma processing apparatus 101 of this embodiment is also provided with the processing state detection unit 8, the above-mentioned effects can be enjoyed.

Above, the embodiment has been exemplified. However, the present invention is not limited to those described. Regarding the above-mentioned embodiments, any appropriate design changes made by those skilled in the art, as long as they have the characteristics of the present invention, are included in the scope of the present invention. For example, the shape, material, arrangement, etc. of the constituent elements included in the plasma processing apparatus 1, 101 are not limited to those illustrated, and can be appropriately changed. In addition, the various requirements provided in the above-mentioned embodiments can be combined where possible, and those combinations that include the features of the present invention are also included in the scope of the present invention.

1: Plasma processing device 2: chamber 2a: central axis 2b: hole 2c: straight line 3: Mounting the module 4: Power supply department 5: Power supply department 6: Decompression department 7: Gas supply department 8: Processing status detection department 9: Control Department 21: Body part 21a: bottom plate 21a1: hole 21b: area 21c: Move in and out 21c1: Gate valve 22: top plate 22a: hole 22b: Gas supply port 23: window 23a: Noodles 31: Placement Department 31a: Electrode 31a1: Pickup pin 31b: Insulating ring 31c: Pedestal 32: Support Department 32a: Installation Department 32a1: hole 32a2: hole 32b: beam 32c: flange 32c1: hole 33: cover 41: Power 42: matching department 42a: matching circuit 42b: Fan 42c: bus 51: Electrode 52: Power 53: matching circuit 54: Faraday shield 55: Wiring 61: Pump 61a: suction port 62: Valve 62a: Valve body 62a1: axis 62b: Drive section 71: Gas Storage Department 72: Gas Control Department 73: On-off valve 81: Light Path Change Department 81a: Noodles 81b: Optical Path Change Department 81ba: Noodles 81c: Optical Path Change Department 81ca: Noodles 81d: Light path change department 81da: side 82: Detection Department 83: Light guide 100: processing object 101: Plasma processing device 102: Chamber 102a: body part 102b: area 102c: Move in and out 102d: Gate valve 102e: exhaust port 103: Placement Department 103a: Electrode 103b: pedestal 103c: Insulating ring 106: Decompression Department 106a: pump 106b: Pressure Control Department 109: Control Department 181: Light Path Change Department 181a: end face 181b: recess B: straight line d: depth dimension D: cross-sectional area G: gas La: incident light Lb: Outgoing light P: Plasma t1: wall thickness t2: wall thickness

FIG. 1 is a schematic cross-sectional view for illustrating the plasma processing apparatus of this embodiment. Fig. 2 is a schematic three-dimensional view for illustrating the mounting module. Fig. 3 is a schematic cross-sectional view for illustrating the light path changing part. 4(a) and (b) are schematic cross-sectional views for illustrating a modification example of the optical path changing part. FIG. 5 is a schematic cross-sectional view for illustrating another modification example of the optical path changing part. Fig. 6 is a schematic plan view for illustrating the flat surface provided on the side surface of the window. Figures 7(a) and (b) are schematic cross-sectional views for illustrating another embodiment of the light path changing part. Fig. 8 is a schematic cross-sectional view for illustrating another embodiment of a plasma processing apparatus.

1: Plasma processing device

2: chamber

2a: central axis

2b: hole

3: Mounting the module

4: Power supply department

5: Power supply department

6: Decompression department

7: Gas supply department

8: Processing status detection department

9: Control Department

21: Body part

21a: bottom plate

21a1: hole

21b: area

21c: Move in and out

21c1: Gate valve

22: top plate

22a: hole

22b: Gas supply port

23: window

31: Placement Department

31a: Electrode

31b: Insulating ring

31c: Pedestal

32: Support Department

32a: Installation Department

32a1: hole

32a2: hole

32b: beam

32c: flange

32c1: hole

33: cover

41: Power

42: matching department

42a: matching circuit

42b: Fan

42c: bus

51: Electrode

52: Power

53: matching circuit

54: Faraday shield

55: Wiring

61: Pump

61a: suction port

62: Valve

62a: Valve body

62a1: axis

62b: Drive section

71: Gas Storage Department

72: Gas Control Department

73: On-off valve

81: Light Path Change Department

82: Detection Department

83: Light guide

100: processing object

G: gas

P: Plasma

t1: wall thickness

t2: wall thickness

Claims (18)

A plasma processing device, which includes: A chamber, which is configured to maintain a decompressed gas environment below atmospheric pressure; A gas supply part, which is configured to supply gas to the inside of the above-mentioned chamber; The placing part is arranged inside the above-mentioned chamber and is configured to hold the processed object; A decompression part, which is configured to decompress the inside of the above-mentioned chamber; A window, which is provided in the above-mentioned chamber and opposite to the above-mentioned placing part; A plasma generator, which is provided on the outside of the chamber and on the opposite side of the window to the mounting portion, and is configured to generate plasma inside the chamber; The light path changing part is arranged inside the window and has a surface inclined with respect to the central axis of the chamber; and The detecting portion is provided on the side surface of the window and facing the surface of the optical path changing portion. The plasma processing device of claim 1, wherein a part of the light generated inside the chamber is reflected by the surface of the optical path changing portion, and is configured to be incident on the detection portion. Such as the plasma processing device of claim 1, wherein the detection unit includes: The light projecting part, which irradiates light to the surface of the light path changing part; The light receiving section receives interference light, which is generated by light reflected on the surface of the processed object and traveling toward the light receiving section through the optical path changing section, and light emitted from the light projecting section. The plasma processing device of claim 1, wherein the surface of the optical path changing portion is flat, and the angle between the surface and the center axis of the chamber is 45°. The plasma processing device of claim 3, wherein the light from the detection portion toward the surface is incident on the surface at 45° and reflected at 45°. The plasma processing apparatus of claim 1, wherein the light path changing portion is a recessed portion that is open on a surface of the window opposite to the placing portion. Such as the plasma processing device of claim 1, where A flat surface is provided on the part of the side surface of the window opposite to the detection part, and A light guide part is further provided between the flat surface and the detection part. Such as the plasma processing device of claim 7, where The light guide portion includes a plurality of optical fibers; The detection unit includes a plurality of spectroscopes; and One of the optical fibers is connected to one of the optical splitters. The plasma processing device of claim 3, wherein the surface of the optical path changing portion is flat, and the angle between the surface and the center axis of the chamber is 45°. The plasma processing device of claim 9, wherein the light from the detection portion toward the surface is incident on the surface at 45° and reflected at 45°. The plasma processing device of claim 3, wherein the light path changing portion is a recessed portion that is open on the surface of the window opposite to the placing portion. The plasma processing device of claim 10, wherein the light path changing portion is a recessed portion that is open on the surface of the window opposite to the placing portion. Such as the plasma processing device of claim 3, where A flat surface is provided on the part of the side surface of the window opposite to the detection part, and A light guide part is further provided between the flat surface and the detection part. Such as the plasma processing device of claim 11, where A flat surface is provided on the part of the side surface of the window opposite to the detection part, and A light guide part is further provided between the flat surface and the detection part. Such as the plasma processing device of claim 12, where A flat surface is provided on the part of the side surface of the window opposite to the detection part, and A light guide part is further provided between the flat surface and the detection part. Such as the plasma processing device of claim 13, wherein The light guide portion includes a plurality of optical fibers; The detection unit includes a plurality of spectroscopes; and One of the optical fibers is connected to one of the optical splitters. Such as the plasma processing device of claim 14, wherein The light guide portion includes a plurality of optical fibers; The detection unit includes a plurality of spectroscopes; and One of the optical fibers is connected to one of the optical splitters. Such as the plasma processing device of claim 15, where The light guide portion includes a plurality of optical fibers; The detection unit includes a plurality of spectroscopes; and One of the optical fibers is connected to one of the optical splitters.

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