Method for cleaning a plasma etching apparatus

Abstract

To provide a cleaning method of a plasma etching device that can clean up a foreign matter on a retention surface in a chamber without opening the chamber.SOLUTION: A cleaning method of a plasma etching device includes a cleaning jig setting step of covering a holding surface 21 of a holding table 20 in a chamber 10 with a cleaning jig 200 having an adhesive surface 209 having adherence properties or producing adherence properties due to an external stimulus on a surface in contact with the holding surface 21, and an oxygen plasma supply step of supplying plasma into the chamber 10. In the oxygen plasma supply step, an inner wall cleaning step of removing a foreign matter attached to the inner wall of the chamber 10 with oxygen plasma gas 400, and a holding surface cleaning step of heating the cleaning jig 200 using heat generated by the oxygen plasma gas 400, bringing the softened adhesive surface 209 into close contact with the holding surface 21, and capturing the foreign matter attached to the holding surface 21 with the adhesive surface 209 are performed.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for cleaning a plasma etching apparatus, which removes foreign matter adhering to a holding surface in the plasma etching apparatus. [Background technology]

[0002] BACKGROUND ART A plasma etching apparatus is known that divides a workpiece such as a wafer by plasma etching (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-171291 Summary of the Invention [Problem to be solved by the invention]

[0004] In such plasma etching equipment, to control the workpiece temperature during etching, helium gas, which has high thermal conductivity, is filled between the workpiece and the holding surface. However, if foreign matter is present on the holding surface, the adhesion between the workpiece and the holding surface decreases, causing the helium gas to leak into the vacuum inside the chamber. Furthermore, if helium gas leaks into the chamber, the workpiece temperature cannot be controlled, resulting in a deterioration in processing quality, or the environment inside the chamber changes, affecting the processing rate and causing unstable processing.

[0005] Therefore, in order to periodically clean the holding surface of a plasma etching apparatus, the chamber is returned to atmospheric pressure, and then the chamber is opened and cleaned. However, once the chamber is returned to atmospheric pressure, it takes time to create a vacuum again. In addition, opening the chamber poses the risk of new foreign matter entering the chamber.

[0006] The present invention has been made in consideration of the above problems, and its object is to provide a method for cleaning a plasma etching apparatus that can clean foreign matter on a holding surface inside a chamber without opening the chamber. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the method for cleaning a plasma etching apparatus of the present invention is a method for cleaning a plasma etching apparatus that supplies plasma into a chamber to etch a workpiece held on the holding surface of a holding table, and is characterized by comprising: a cleaning jig installation step of covering the holding surface with a cleaning jig having an adhesive surface that is adhesive or becomes adhesive in response to an external stimulus on a surface that comes into contact with the holding surface; and an oxygen plasma supply step of supplying plasma into the chamber, wherein the oxygen plasma supply step also comprises an inner wall cleaning step of removing foreign matter adhering to the inner wall of the chamber using oxygen plasma; and a holding surface cleaning step of heating the cleaning jig using heat generated by the oxygen plasma to bring the softened adhesive surface into close contact with the holding surface and capturing foreign matter adhering to the holding surface with the adhesive surface.

[0008] The support surface cleaning step may be carried out under at least one of the following conditions: a lower pressure in the chamber and / or a vertical bias is applied, as compared to the inner wall cleaning step.

[0009] The plasma etching apparatus may further include a transport arm for transporting a workpiece to the chamber, and a transport port formed in the chamber to allow transport by the transport arm, and the cleaning jig may be transported to the chamber by the transport arm shared with the workpiece, using the transport port.

[0010] The holding table may be an electrostatic chuck, and the cleaning jig may be electrostatically attracted to the holding surface in the cleaning jig installation step.

[0011] The holding table may have a heating unit, and in the oxygen plasma supplying step, the holding table may be heated to heat the cleaning jig.

[0012] The cleaning jig may be an adhesive tape having a base layer and an adhesive layer, and the adhesive layer may be the adhesive surface.

[0013] The cleaning tool may be a sheet made of a thermoplastic resin without an adhesive layer, and may become adhesive when heated. [Effects of the Invention]

[0014] In the present invention, a cleaning jig is transported from a transport port onto the holding surface of a holding table inside a chamber without opening the chamber, and the adhesive surface of the cleaning jig is brought into close contact with the holding surface, thereby capturing foreign matter on the holding surface, thereby making it possible to clean foreign matter on the holding surface inside the chamber without opening the chamber. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the configuration of a plasma etching apparatus to be cleaned by a method for cleaning a plasma etching apparatus according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the plasma etching apparatus of FIG. [Figure 3] FIG. 3 is a flowchart showing the procedure of the method for cleaning the plasma etching apparatus according to the embodiment. [Figure 4] FIG. 4 is a perspective view showing an example of the configuration of a cleaning jig used in the method for cleaning a plasma etching apparatus according to an embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing the cleaning jig of FIG. [Figure 6] FIG. 6 is a cross-sectional view illustrating the cleaning jig installation step of FIG. [Figure 7] FIG. 7 is a cross-sectional view illustrating the inner wall cleaning step in the oxygen plasma supply step of FIG. [Figure 8]FIG. 8 is a cross-sectional view illustrating the support surface cleaning step in the oxygen plasma supply step of FIG. [Figure 9] FIG. 9 is a cross-sectional view illustrating a process at the end of the cleaning method for the plasma etching apparatus of FIG. [Figure 10] FIG. 10 is a cross-sectional view showing an example of the configuration of a cleaning jig used in the method for cleaning a plasma etching apparatus according to the first modification. [Figure 11] FIG. 11 is a cross-sectional view showing an example of the configuration of a cleaning jig used in the method for cleaning a plasma etching apparatus according to the second modification. [Figure 12] FIG. 12 is a perspective view showing an example of the configuration of a cleaning jig used in the method for cleaning a plasma etching apparatus according to the third modification. DETAILED DESCRIPTION OF THE INVENTION

[0016] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0017] [Embodiment] A method for cleaning a plasma etching apparatus according to an embodiment of the present invention will be described with reference to the drawings. Figures 1 and 2 are cross-sectional views showing an example of the configuration of a plasma etching apparatus 1, which is the target of cleaning by the method for cleaning a plasma etching apparatus according to the embodiment. As shown in Figures 1 and 2, the plasma etching apparatus 1 includes a chamber 10, a holding table 20, a plasma gas supply unit 30, a transfer arm 40, a transfer port 12, and a control unit 50. Plasma is supplied to the chamber 10 to plasma etch a workpiece 100 held on a holding surface 21 formed on the upper surface of the holding table 20 parallel to a horizontal plane.

[0018] In this embodiment, the plasma etching apparatus 1 is a capacitively coupled plasma (CCP) type as shown in Figures 1 and 2, but the present invention is not limited to this. For example, it may be an inductively coupled plasma (ICP) type in which high-frequency power for generating plasma is applied to an induction coil and the etching gas is converted into plasma by interaction with the magnetic field formed in the induction coil, or it may be an electron cyclotron resonance plasma (ECR) type in which plasma is generated by utilizing cyclotron resonance of electrons in combination with microwaves of predetermined wavelengths.

[0019] 1 and 2, the workpiece 100 to be plasma etched by the plasma etching apparatus 1 is, in this embodiment, a disk-shaped semiconductor wafer or optical device wafer made of a base material such as silicon, sapphire, silicon carbide (SiC), gallium arsenide, or glass. The workpiece 100 has chip-sized devices formed in areas partitioned by a plurality of planned division lines formed in a grid pattern on a flat surface 101. In this embodiment, as shown in FIGS. 1 and 2, the workpiece 100 has an adhesive tape 105 attached to a back surface 104 on the back side of the front surface 101, and an annular frame 106 attached to the outer edge of the adhesive tape 105.

[0020] The chamber 10 houses a holding table 20 inside. The chamber 10 has a transfer port 12 formed in its side wall, which allows the transfer of the workpiece 100 by the transfer arm 40 and connects the inside and outside of the chamber 10. The chamber 10 is a container that forms an enclosed space 11 inside, excluding the transfer port 12. The chamber 10 is grounded. The transfer port 12 is provided with an opening / closing door 13 that opens and closes the transfer port 12. The opening / closing door 13 opens and closes the transfer port 12 by moving vertically using an air cylinder.

[0021] A front chamber 18 is provided adjacent to the chamber 10 via a transfer port 12 and an opening / closing door 13. The front chamber 18 allows the workpiece 100 to be temporarily placed before or after being transferred into the chamber 10. The opening / closing door 13 separates the interior of the chamber 10 from the front chamber 18 by closing the transfer port 12, and connects the interior of the chamber 10 to the front chamber 18 via the transfer port 12 by opening the transfer port 12. When the sealed space 11 of the chamber 10 is in a reduced pressure state where the pressure is reduced below atmospheric pressure, the opening / closing door 13 opens the transfer port 12 after the front chamber 18 has been reduced in pressure. Therefore, the opening of the transfer port 12 prevents the interior of the chamber 10 from reaching atmospheric pressure and maintains the reduced pressure state.

[0022] An exhaust port 14 is formed at the bottom of the chamber 10, and an exhaust device 15 is connected to the exhaust port 14. By exhausting the inside of the chamber 10 using the exhaust device 15 through the exhaust port 14, the sealed space 11 inside the chamber 10 can be decompressed, for example, to create a vacuum atmosphere.

[0023] A plasma gas supply unit 30 is installed at the top of chamber 10, and a frame overheating prevention guard 16 for preventing heating of frame 106 during plasma etching is disposed between plasma gas supply unit 30 and holding table 20. Frame overheating prevention guard 16 is, for example, an annular flat plate made of stainless steel or the like that is resistant to etching gas, and is disposed on the inner wall of chamber 10 so as to extend radially inward.

[0024] The holding table 20 is made of a dielectric material such as ceramic, and is supported from below by a support member 29 inside the chamber 10. The holding table 20 is a so-called electrostatic chuck (ESC) that applies a voltage from a bias high-frequency power supply 23 via a matching box 24 to an electrode 22 disposed inside the holding table 20 parallel to a holding surface 21, thereby generating a dielectric polarization phenomenon between the holding surface 21 and the workpiece 100 on the holding surface 21, and attracts and holds the workpiece 100 on the holding surface 21 by an electrostatic attraction force generated by polarization of the electric charge.

[0025] A water passage (not shown) is formed inside the holding table 20, and the holding table 20 is cooled to a predetermined temperature from the inside by cooling water circulating through the water passage. In addition, a heat transfer gas such as He gas flows at a predetermined pressure between the holding surface 21 and the workpiece 100 held by the holding surface 21 in order to improve the heat absorption efficiency of the workpiece 100 by the cooling water. In this embodiment, the holding table 20 is a monopolar electrostatic chuck as shown in FIGS. 1 and 2, but the present invention is not limited to this and may be, for example, a bipolar electrostatic chuck.

[0026] The holding table 20 is provided with a plurality of pins 25 (two in the example shown in FIGS. 1 and 2) that are erected so as to be able to rise and fall from the holding surface 21. When the workpiece 100 is loaded onto or unloaded from the holding table 20, the pins 25 are positioned at a position (protruding position) that protrudes upward from the holding surface 21 as shown in FIG. 2, and when the workpiece 100 is held by suction on the holding surface 21 of the holding table 20, the pins 25 are positioned at a recessed position (recessed position) that does not protrude upward from the holding surface 21 as shown in FIG. 3. The holding table 20 has a heating unit 26 therein that heats the holding table 20.

[0027] A gas supply source 32 is connected to the upper part of the plasma gas supply unit 30, and from the gas supply source 32, an etching gas for etching the workpiece 100, a gas for returning the sealed space 11 to atmospheric pressure, and oxygen gas used in the method for cleaning a plasma etching apparatus according to the embodiment are supplied. The etching gas is, for example, a fluorine-based gas such as SF, CF, C2F6, or C4F8. The plasma gas supply unit 30 supplies the gas supplied from the gas supply source 32 to the workpiece 100 held on the holding table 20 from a plurality of supply ports 31 (eight in the example shown in FIGS. 1 and 2) formed therein toward the holding table 20 below. The plasma gas supply unit 30 applies a voltage from a high-frequency power supply 33 via a matching box 34, thereby generating a high-frequency electric field between the plasma gas supply unit 30, which serves as the upper electrode, and the electrode 22 in the holding table 20, which serves as the lower electrode, and converts the etching gas and oxygen gas supplied from the gas supply source 32 into plasma to produce a plasma etching gas 300 (see Figure 2) and an oxygen plasma gas 400 (see Figures 7 and 8).

[0028] The transfer arm 40 transfers the workpiece 100 to the chamber 10. The transfer arm 40 is installed at the height of a transfer opening 12 formed in the chamber 10 so that it can pass through the transfer opening 12 in the horizontal direction. The transfer arm 40 holds and transfers the workpiece 100 from, for example, a cassette (not shown) outside the chamber 10, and transfers it through the transfer opening 12 onto pins 25 that protrude upward from the holding surface 21 of the holding table 20 inside the chamber 10. The transfer arm 40 holds the workpiece 100 on the pins 25 that protrude upward from the holding surface 21 of the holding table 20 inside the chamber 10, and transfers it out of the chamber 10 through the transfer opening 12.

[0029] The control unit 50 controls the operation of each component of the plasma etching apparatus 1, causing the plasma etching apparatus 1 to perform a plasma etching process on the workpiece 100, a cleaning method for a plasma etching apparatus according to an embodiment described below, and the like. In this embodiment, the control unit 50 controls, for example, the opening and closing operation of the transfer port 12 by the opening and closing door 13, the depressurization operation of the sealed space 11 in the chamber 10 through the exhaust port 14 by the exhaust device 15, the suction and holding operation of the holding table 20, the raising and lowering operation of the pins 25, the cooling operation of the holding table 20 and the heating operation by the heating unit 26, the type, discharge amount, and discharge time of the gas supplied from the plasma gas supply unit 30 into the chamber 10, the conditions of the high-frequency voltages applied from the bias high-frequency power supply 23 and the high-frequency power supply 33, and the holding and transport operation of the workpiece 100 and the cleaning jig 200 by the transport arm 40.

[0030] In this embodiment, the control unit 50 includes a computer system. The computer system included in the control unit 50 includes an arithmetic processing device having a microprocessor such as a CPU (Central Processing Unit), a storage device having memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and an input / output interface device. The arithmetic processing device of the control unit 50 performs arithmetic processing in accordance with a computer program stored in the storage device of the control unit 50, and outputs control signals for controlling the plasma etching apparatus 1 to each component of the plasma etching apparatus 1 via the input / output interface device of the control unit 50.

[0031] An example of the operation process of the plasma etching apparatus 1 having the above configuration will be described below. In the plasma etching apparatus 1, first, the transfer opening 12 is opened by the opening / closing door 13, and the pins 25 of the holding table 20 are positioned in the protruding position. Then, the transfer arm 40 transfers the workpiece 100 from the anterior chamber 18 through the transfer opening 12 into the chamber 10 onto the pins 25 of the holding table 20.

[0032] The plasma etching apparatus 1 then retracts the transport arm 40 outside the chamber 10, and then lowers the pin 25 of the holding table 20 to a recessed position to bring the workpiece 100 into contact with the holding surface 21, and applies a voltage to the electrode 22 from the bias high-frequency power supply 23 to adsorb and hold the workpiece 100 on the holding surface 21.Then, the transport opening 12 is closed by the opening / closing door 13, and the sealed space 11 within the chamber 10 is evacuated and reduced in pressure by the exhaust device 15 to create a vacuum atmosphere.

[0033] In the plasma etching apparatus 1, a voltage is applied from a high frequency power supply 33 by a plasma gas supply unit 30, and the etching gas supplied from a gas supply source 32 through a supply port 31 toward the workpiece 100 held on a holding table 20 in the chamber 10 is converted into plasma to produce plasma etching gas 300, and the workpiece 100 held on the holding table 20 is plasma-etched using the plasma etching gas 300. The plasma etching apparatus 1 divides the workpiece 100 into individual devices, for example by plasma etching the workpiece 100 along the planned division lines to form machined grooves.

[0034] When the plasma etching process of the workpiece 100 is completed, the plasma etching apparatus 1 stops the supply of etching gas from the gas supply source 32 and stops the application of voltage from the high-frequency power supply 33, thereby stopping the supply of plasma etching gas 300 from the plasma gas supply unit 30 and causing the holding table 20 to stop suction and holding of the workpiece 100 on the holding surface 21. Then, the plasma etching apparatus 1 opens the transfer opening 12 with the opening / closing door 13, positions the pins 25 of the holding table 20 in the protruding position, thereby separating the workpiece 100 vertically upward from the holding surface 21, and then uses the transfer arm 40 to transfer the workpiece 100 from above the pins 25 of the holding table 20 in the chamber 10 through the transfer opening 12 to the antechamber 18 outside the chamber 10.

[0035] Fig. 3 is a flowchart showing the processing steps of a method for cleaning a plasma etching apparatus according to an embodiment. The method for cleaning a plasma etching apparatus according to an embodiment is a method for cleaning a plasma etching apparatus 1, and includes a cleaning jig installation step 1001 and an oxygen plasma supply step 1002, as shown in Fig. 3. The method for cleaning a plasma etching apparatus according to an embodiment is carried out, for example, after plasma etching of one workpiece 100 is completed, or after plasma etching of all workpieces 100 (e.g., 25 workpieces) contained in one cassette is completed.

[0036] 4 and 5 are a perspective view and a cross-sectional view, respectively, showing an example of a cleaning jig 200 used in the method for cleaning a plasma etching apparatus according to the embodiment. The cleaning jig 200 is used in the method for cleaning a plasma etching apparatus according to the embodiment. In this embodiment, as shown in FIG. 5, the cleaning jig 200 is an adhesive tape having a base layer 201 and an adhesive layer 202. Here, the adhesive layer 202 is made of an adhesive synthetic resin and is laminated on one side of the base layer 201. The base layer 201 is also made of a synthetic resin. Specifically, the cleaning jig 200 has a base layer 201 of a size similar to that of the adhesive tape 105 described above, i.e., a size sufficient to cover the holding surface 21, and adhesive layers 202 of a size similar to that of the base layer 201 formed on both sides of the base layer 201. In this embodiment, as shown in FIG. 4, the cleaning jig 200 further has an annular frame 206 attached to the outer edge of one of the adhesive layers 202. The annular frame 206 has a shape and size similar to that of the annular frame 106.

[0037] The cleaning jig 200 with the frame 206 attached in this manner has the same shape as the workpiece 100 with the frame 106 attached, and therefore can be transported by the transport arm 40 and held by the holding table 20 in the same manner as the workpiece 100 with the frame 106 attached.

[0038] Cleaning jig installation step 1001 is a step of covering holding surface 21 with a cleaning jig having an adhesive surface that is adhesive or that becomes adhesive in response to an external stimulus, on the surface that comes into contact with holding surface 21 of holding table 20. In this embodiment, cleaning jig installation step 1001 covers holding surface 21 with cleaning jig 200 having, on the surface that comes into contact with holding surface 21 of holding table 20, an exposed surface of glue layer 202 formed on the surface opposite to the surface on which frame 206 is attached, as adhesive surface 209 having adhesiveness.

[0039] 6 is a cross-sectional view illustrating the cleaning jig installation step 1001 in FIG. 3. In the cleaning jig installation step 1001, first, as shown in FIG. 6, with no workpiece 100 or the like held on the holding surface 21 of the holding table 20, the transfer opening 12 is opened by the opening / closing door 13, the pins 25 of the holding table 20 are positioned in the protruding position, and then the cleaning jig 200 is transferred by the transfer arm 40 from the antechamber 18 through the transfer opening 12 to the pins 25 of the holding table 20 in the chamber 10. In the cleaning jig installation step 1001, the transfer arm 40 is then retracted to the outside of the chamber 10, and the pins 25 of the holding table 20 are lowered to the recessed position, thereby bringing the adhesive layer 202 formed on the surface of the cleaning jig 200 opposite the surface on which the frame 206 is attached into contact with the holding surface 21, and the cleaning jig 200 covers the holding surface 21. In the cleaning jig installation step 1001, the transfer port 12 is then closed by the opening and closing door 13, and the sealed space 11 in the chamber 10 is evacuated and decompressed by the exhaust device 15 to create a vacuum atmosphere.

[0040] The oxygen plasma supply step 1002 is a step of supplying oxygen plasma into the chamber 10. In this embodiment, the oxygen plasma supply step 1002 is performed in an inner wall cleaning step 1021 and a holding surface cleaning step 1022, as shown in FIG. 3 . The inner wall cleaning step 1021 is a step of removing foreign matter adhering to the inner wall of the chamber 10 by oxygen plasma in the oxygen plasma supply step 1002. The holding surface cleaning step 1022 is a step of heating the cleaning jig 200 by utilizing the heat generated by the oxygen plasma in the oxygen plasma supply step 1002, bringing the softened adhesive surface 209 into close contact with the holding surface 21, and capturing foreign matter adhering to the holding surface 21 by the adhesive surface 209.

[0041] Fig. 7 is a cross-sectional view illustrating inner wall cleaning step 1021 of oxygen plasma supply step 1002 in Fig. 3. In inner wall cleaning step 1021, as shown in Fig. 7, plasma gas supply unit 30 applies a voltage from high frequency power supply 33 to convert oxygen gas supplied from gas supply source 32 into chamber 10 through supply port 31 into plasma to produce oxygen plasma gas 400, and foreign matter adhering to the inner wall of chamber 10 is removed by oxygen plasma gas 400.

[0042] In the inner wall cleaning step 1021, no voltage is applied to the electrode 22 from the bias high frequency power supply 23, or the voltage applied is smaller than that during plasma etching, so that the oxygen plasma gas 400 is isotropically irradiated into the chamber 10. In this way, in the inner wall cleaning step 1021, the oxygen plasma gas 400 is irradiated onto the inner wall of the chamber 10, and the oxygen plasma gas 400 chemically reacts with organic foreign matter adhering to the inner wall of the chamber 10, converting it into CO gas or the like and removing it.

[0043] 8 is a cross-sectional view illustrating the support surface cleaning step 1022 of the oxygen plasma supply step 1002 in FIG. The support surface cleaning step 1022 is performed by maintaining the supply of oxygen plasma gas 400 following the inner wall cleaning step 1021, while at least one of lowering the pressure in the sealed space 11 of the chamber 10 compared to the inner wall cleaning step 1021 and applying a vertical bias. Applying a vertical bias here refers to applying a voltage to the electrode 22 from the bias high-frequency power supply 23, or applying a voltage higher than that applied during plasma etching, thereby applying a higher voltage to the electrode 22 from the bias high-frequency power supply 23 than that in the inner wall cleaning step 1021. The lower pressure state in the sealed space 11 of the chamber 10 is achieved by increasing the exhaust and pressure reduction of the sealed space 11 in the chamber 10 by the exhaust device 15.

[0044] In the holding surface cleaning step 1022, the pressure in the sealed space 11 of the chamber 10 is lowered than in the inner wall cleaning step 1021, or a bias is applied in the vertical direction, thereby making it possible to anisotropically irradiate the oxygen plasma gas 400 vertically downward within the chamber 10, as shown in Fig. 8. In other words, the oxygen plasma gas 400 can be made to travel in a straight line vertically downward. In this way, in the holding surface cleaning step 1022, the heat generated by the irradiation of the oxygen plasma gas 400 is used to heat and soften the cleaning jig 200 on the holding surface 21 of the holding table 20 to which the oxygen plasma gas 400 is irradiated, and the adhesive surface 209 of the softened adhesive layer 202 is brought into close contact with the holding surface 21, so that foreign matter adhering to the holding surface 21 is captured by the adhesive surface 209 of the adhesive layer 202. In addition, in the holding surface cleaning step 1022, the adhesive surface 209 of the adhesive layer 202 of the cleaning jig 200 may be brought into closer contact with the holding surface 21 by the electrostatic adsorption force generated on the holding table 20, thereby making it easier to capture foreign matter.

[0045] In the holding surface cleaning step 1022, the holding table 20 may further be heated by the heating unit 26 of the holding table 20, and the cleaning jig 200 on the holding surface 21 of the holding table 20 may be heated and softened via the holding table 20, thereby making the adhesive surface 209 of the softened adhesive layer 202 adhere more closely to the holding surface 21.

[0046] 9 is a cross-sectional view illustrating the process of completing the cleaning method for the plasma etching apparatus of FIG. 3. After performing inner wall cleaning step 1021 and holding surface cleaning step 1022 of oxygen plasma supply step 1002, the supply of oxygen gas from gas supply source 32 is stopped, and the application of voltage from high-frequency power supply 33 is stopped, thereby stopping the supply of oxygen plasma gas 400 from plasma gas supply unit 30. If cleaning jig 200 is being held by suction on holding surface 21 of holding table 20, this suction and holding is stopped. Then, pins 25 of holding table 20 are positioned in the protruding position, whereby adhesive surface 209 of adhesive layer 202 of cleaning jig 200 is peeled off from holding surface 21, thereby peeling off foreign matter captured on adhesive surface 209 of adhesive layer 202 from holding surface 21. Then, as shown in Figure 9, the transport opening 12 is opened by the opening / closing door 13, and the cleaning jig 200 on the pin 25 of the holding table 20 inside the chamber 10 is transported through the transport opening 12 by the transport arm 40 to the antechamber 18 outside the chamber 10, thereby discharging the foreign matter captured by the adhesive surface 209 of the adhesive layer 202 outside the chamber 10.

[0047] The method for cleaning a plasma etching apparatus according to the embodiment having the above-described configuration involves transporting cleaning jig 200 from transport port 12 onto holding surface 21 of holding table 20 inside chamber 10 without opening chamber 10, and bringing adhesive surface 209 of adhesive layer 202 of cleaning jig 200 into close contact with holding surface 21, thereby capturing foreign matter on holding surface 21, thereby achieving the advantageous effect of being able to clean foreign matter on holding surface 21 inside chamber 10 without opening chamber 10. Therefore, the method for cleaning a plasma etching apparatus according to the embodiment can reduce the risk of new foreign matter entering the chamber 10, which would otherwise occur if chamber 10 were opened.

[0048] In addition, in the cleaning method for the plasma etching apparatus according to the embodiment, the oxygen plasma supply step 1002 is carried out in two steps: an inner wall cleaning step 1021 in which oxygen plasma gas 400 is isotropically irradiated into the chamber 10 to thoroughly remove foreign matter adhering to the inner wall of the chamber 10; and a holding surface cleaning step 1022 in which oxygen plasma gas 400 is anisotropically irradiated vertically downward into the chamber 10 to heat and soften the adhesive surface 209 of the adhesive layer 202 of the cleaning jig 200 using the heat generated by the irradiation of the oxygen plasma gas 400, thereby adhering it to the holding surface 21 and capturing the foreign matter adhering to the holding surface 21. Therefore, both the foreign matter adhering to the inner wall of the chamber 10 and the foreign matter adhering to the holding surface 21 can be efficiently removed without opening the chamber 10 or installing a new heat source for heating and softening the adhesive surface 209 of the adhesive layer 202 of the cleaning jig 200.

[0049] Furthermore, in the method for cleaning a plasma etching apparatus according to the embodiment, the holding surface cleaning step 1022 is performed under at least one of the following conditions: the pressure in the sealed space 11 of the chamber 10 is lower than that in the inner wall cleaning step 1021; or a bias is applied in the vertical direction. Therefore, while the oxygen plasma gas 400 is isotropically irradiated in the inner wall cleaning step 1021, the oxygen plasma gas 400 can be anisotropically irradiated in the holding surface cleaning step 1022 while maintaining the supply of the oxygen plasma gas 400. This makes it possible to efficiently and quickly switch from removing foreign matter adhering to the inner wall of the chamber 10 to removing foreign matter adhering to the holding surface 21.

[0050] Furthermore, in the method for cleaning the plasma etching apparatus according to the embodiment, the plasma etching apparatus 1 further includes a transport arm 40 for transporting the workpiece 100 to the chamber 10, and a transport port 12 formed in the chamber 10 that allows transport by the transport arm 40, and the cleaning jig 200 is transported to the chamber 10 using the transport port 12 by the transport arm 40 that is also used for the workpiece 100, so that the method can be implemented at low cost without installing any new equipment or mechanism for transporting the cleaning jig 200 onto the holding surface 21 of the holding table 20 in the chamber 10.

[0051] Furthermore, in the method for cleaning a plasma etching apparatus according to the embodiment, the holding table 20 is an electrostatic chuck, and in the cleaning jig installation step 1001, the cleaning jig 200 is electrostatically adsorbed to the holding surface 21 of the holding table 20, thereby making the adhesive surface 209 of the adhesive layer 202 of the cleaning jig 200 adhere more closely to the holding surface 21, thereby enhancing the effect of capturing foreign matter adhering to the holding surface 21.

[0052] Furthermore, in the method for cleaning a plasma etching apparatus according to the embodiment, the holding table 20 has a heating unit 26, and in the oxygen plasma supply step 1002, the holding table 20 is heated by the heating unit 26, which in turn heats the cleaning jig 200, thereby making it possible to bring the adhesive surface 209 of the adhesive layer 202 of the cleaning jig 200 into closer contact with the holding surface 21, thereby enhancing the effect of capturing foreign matter adhering to the holding surface 21.

[0053] Furthermore, in the cleaning method for the plasma etching apparatus according to the embodiment, the cleaning jig 200 is an adhesive tape having a base layer 201 and an adhesive layer 202, and the adhesive layer 202 is the adhesive surface 209, so that the cleaning jig 200 can be easily formed, and the cleaning effect of the cleaning jig 200 can be easily restored by replacing the adhesive tape.

[0054] [Variation 1] A method for cleaning a plasma etching apparatus according to Modification 1 of the present invention will be described with reference to the drawings. Fig. 10 is a cross-sectional view showing an example of the configuration of a cleaning jig 200-2 used in the method for cleaning a plasma etching apparatus according to Modification 1. In Fig. 10, the same parts as those in the embodiment are designated by the same reference numerals, and their description will be omitted.

[0055] The method for cleaning a plasma etching apparatus according to Modification 1 is the same as the method for cleaning a plasma etching apparatus according to the embodiment, except that the cleaning jig 200 used is changed to cleaning jig 200-2 shown in FIG. 10. As shown in FIG. 10, cleaning jig 200-2 according to Modification 1 is the same as cleaning jig 200 according to the embodiment, except that the adhesive layer 202 on the side on which frame 206 is attached is changed to only the portion facing frame 206. The adhesive layer 202 and adhesive surface 209 on the side opposite to the side on which frame 206 is attached, which contacts and covers holding surface 21 of holding table 20, are the same as those of cleaning jig 200 according to the embodiment. Therefore, the method for cleaning a plasma etching apparatus according to Modification 1 achieves the same effects as the method for cleaning a plasma etching apparatus according to the embodiment.

[0056] [Variation 2] A method for cleaning a plasma etching apparatus according to Modification 2 of the present invention will be described with reference to the drawings. Fig. 11 is a cross-sectional view showing an example of the configuration of a cleaning jig 200-3 used in the method for cleaning a plasma etching apparatus according to Modification 2. In Fig. 11, the same parts as those in the embodiment and Modification 1 are designated by the same reference numerals, and their description will be omitted.

[0057] The method for cleaning a plasma etching apparatus according to Modification 2 is the same as the method for cleaning a plasma etching apparatus according to the embodiment, except that cleaning jig 200 used is changed to cleaning jig 200-3 shown in Fig. 11. As shown in Fig. 11, cleaning jig 200-3 of Modification 2 is the same as cleaning jig 200 according to the embodiment, except that the adhesive tape having base layer 201 and adhesive layer 202 is replaced with a sheet of similar size made of thermoplastic resin (thermoplastic resin sheet). Here, the thermoplastic resin sheet is made of a thermoplastic resin that becomes adhesive when exposed to an external stimulus such as heating. For example, a polyolefin sheet, a polyethylene sheet, a polypropylene sheet, or a polystyrene sheet is preferred, and the thermoplastic resin sheet is attached to frame 206 by thermocompression bonding.

[0058] In cleaning jig installation step 1001 of modified example 2, holding surface 21 is covered with cleaning jig 200-3, which has a surface opposite to the surface on which frame 206 is attached as adhesive surface 209-3 that becomes adhesive in response to an external stimulus, namely heating, on the surface that comes into contact with holding surface 21 of holding table 20. In holding surface cleaning step 1022 of oxygen plasma supply step 1002 of modified example 2, oxygen plasma gas 400 is anisotropically irradiated vertically downward within chamber 10, and the heat generated by the irradiation of oxygen plasma gas 400 is used to heat cleaning jig 200 on holding surface 21 of holding table 20 that is irradiated with oxygen plasma gas 400, causing it to become adhesive, and adhesive surface 209-3 is brought into close contact with holding surface 21, and foreign matter adhering to holding surface 21 is captured by this adhesive surface 209-3.

[0059] In this way, the method for cleaning a plasma etching apparatus according to Modification 2 is achieved by changing cleaning jig 200, which in the embodiment is an adhesive tape having base layer 201 and adhesive layer 202, where adhesive layer 202 is adhesive surface 209, to cleaning jig 200-3, which is a sheet formed of thermoplastic resin without an adhesive layer and which produces adhesive surface 209-3 that becomes adhesive when exposed to an external stimulus such as heating, and therefore achieves the same effects as the method for cleaning a plasma etching apparatus according to the embodiment, except for the adhesive tape having adhesive layer 202. Furthermore, the method for cleaning a plasma etching apparatus according to Modification 2 further uses cleaning jig 200-3 without an adhesive layer, thereby preventing adhesive residue from being left on holding surface 21.

[0060] [Variation 3] A method for cleaning a plasma etching apparatus according to Modification 3 of the present invention will be described with reference to the drawings. Fig. 12 is a perspective view showing an example of the configuration of a cleaning jig 200-4 used in the method for cleaning a plasma etching apparatus according to Modification 3.

[0061] The cleaning method for a plasma etching apparatus according to Modification 3 is the same as the cleaning method for a plasma etching apparatus according to the embodiment, except that the cleaning jig 200 used is changed to a cleaning jig 200-4 shown in FIG. 12 . As shown in FIG. 12 , the cleaning jig 200-4 of Modification 3 includes a substrate 211 large enough to cover the holding surface 21 and a sheet 212 of the same size as the substrate 211, attached to one side of the substrate 211. Here, the substrate 211 is formed in a plate shape such as a disk. For example, it is a dummy wafer formed in a plate shape from the same material as the workpiece 100, without any planned division lines or devices. The sheet 212 is an adhesive tape similar to that used in the cleaning jig 200 of the embodiment, or a thermoplastic resin sheet similar to that used in the cleaning jig 200-3 of Modification 2. Here, the adhesive tape or thermoplastic resin sheet does not necessarily have to be in a sheet shape from the beginning; a powder or liquid may be supplied to one side of the substrate 211 and then formed into a sheet covering that side by thermocompression bonding, pressing, or spin coating. Furthermore, the cleaning jig 200-4 of the third modification may be configured to include a substrate 211 and an adhesive layer 202 formed on one surface of the substrate 211 and having the same size as the substrate 211.

[0062] In all of these cleaning jigs 200-4 of variant example 3, the surface of the sheet 212 opposite to the side to which the substrate 211 is attached becomes the adhesive surface 209-4 that contacts and covers the holding surface 21 of the holding table 20.

[0063] Furthermore, cleaning jig 200-4 of modified example 3 may omit substrate 211 and may be configured with a single adhesive tape similar to cleaning jig 200 of the embodiment, or a single thermoplastic resin sheet similar to cleaning jig 200-3 of modified example 2. In this case, in cleaning jig 200-4 of modified example 3, the surface of sheet 212 opposite to the side where substrate 211 is omitted becomes adhesive surface 209-4 that comes into contact with and covers holding surface 21 of holding table 20.

[0064] These cleaning jigs 200-4 have roughly the same shape as the workpiece 100 without the frame 106 attached, and therefore can be transported by the transport arm 40 and held by the holding table 20 in the same manner as the workpiece 100 without the frame 106 attached.

[0065] In this way, the method for cleaning a plasma etching apparatus according to the third modification is the same as the method for cleaning a plasma etching apparatus according to the embodiment, except that cleaning jig 200 is replaced with cleaning jig 200-4. Therefore, the method for cleaning a plasma etching apparatus according to the third modification has the same effects as the method for cleaning a plasma etching apparatus according to the embodiment and the method for cleaning a plasma etching apparatus according to the second modification.

[0066] The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the gist of the present invention. [Explanation of symbols]

[0067] 1. Plasma etching equipment 10 chambers 12 Transport entrance 20 Holding table 21 Holding surface 26 Heating unit 40 Transfer arm 100 Work 200, 200-2, 200-3, 200-4 Cleaning jig 201 Base material layer 202 Glue layer 209,209-3,209-4 Adhesive surface 400 Oxygen plasma gas

Claims

1. 1. A method for cleaning a plasma etching apparatus that supplies plasma to a chamber to etch a workpiece held on a holding surface of a holding table, comprising: a cleaning jig installation step of covering the holding surface with a cleaning jig having an adhesive surface that is adhesive or becomes adhesive in response to an external stimulus on a surface that comes into contact with the holding surface; an oxygen plasma supply step of supplying plasma into the chamber, In the oxygen plasma supply step, an inner wall cleaning step of removing foreign matter attached to the inner wall of the chamber using oxygen plasma; a holding surface cleaning step of heating the cleaning jig using heat generated by oxygen plasma, bringing the softened adhesive surface into close contact with the holding surface, and capturing foreign matter adhering to the holding surface with the adhesive surface.

2. 2. The method for cleaning a plasma etching apparatus according to claim 1, wherein the support surface cleaning step is carried out under at least one of the following conditions: a lower pressure in the chamber than in the inner wall cleaning step; and a vertical bias is applied.

3. The plasma etching apparatus comprises: a transfer arm that transfers a workpiece to the chamber; a transfer port formed in the chamber to allow transfer by the transfer arm, 2. The method for cleaning a plasma etching apparatus according to claim 1, wherein the cleaning jig is transported to the chamber by the transport arm, which is also used for transporting the workpiece, through the transport port.

4. the holding table is an electrostatic chuck; 2. The method for cleaning a plasma etching apparatus according to claim 1, wherein in the step of placing the cleaning jig, the cleaning jig is electrostatically attracted to the holding surface.

5. the holding table has a heating unit; 2. The method for cleaning a plasma etching apparatus according to claim 1, wherein in the oxygen plasma supply step, the holding table is heated to heat the cleaning jig.

6. 2. The method for cleaning a plasma etching apparatus according to claim 1, wherein the cleaning jig is an adhesive tape having a base layer and an adhesive layer, and the adhesive layer is the adhesive surface.

7. 2. The method for cleaning a plasma etching apparatus according to claim 1, wherein the cleaning jig is a sheet made of a thermoplastic resin without an adhesive layer, and becomes adhesive when heated.

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