JP4579025B2 - Temperature adjusting method, temperature adjusting device, plasma processing device - Google Patents

Description

  The present invention relates to a temperature adjustment method, a temperature adjustment apparatus, and a plasma processing apparatus.

  For example, in a manufacturing process of a semiconductor device or a liquid crystal display device, for example, an etching process using plasma is performed.

  The above etching process is usually performed in a plasma processing apparatus. A parallel plate type in which electrodes are arranged on the upper and lower sides is often used as the plasma processing apparatus. The parallel plate type plasma processing apparatus is used for generating plasma on a lower electrode on which a substrate is placed, for example, in a processing vessel. A high frequency power is applied, plasma is generated between the lower electrode and the upper electrode, and the film on the substrate is etched by the plasma.

  In the above plasma processing apparatus, the temperature of the lower electrode is controlled in order to stabilize the processing of the substrate. For example, in the plasma processing apparatus, a refrigerant circulation circuit that passes through the inside of the lower electrode and communicates with the chiller apparatus is formed. When the substrate is processed, the refrigerant is supplied to the inside of the lower electrode and circulated to reduce the temperature of the lower electrode. It is strictly controlled (see, for example, Patent Document 1).

JP 2002-168551 A

  By the way, the upper electrode is exposed to the plasma generation space, and the temperature of the upper electrode also affects the etching state, so the upper electrode also needs to be temperature controlled. Therefore, it is conceivable to control the temperature of the upper electrode using a chiller device similar to the lower electrode. However, the upper electrode generates a large amount of heat because a high-output high-frequency power for generating plasma is applied, and has a larger heat capacity than the lower electrode. For this reason, the upper electrode generates a large amount of heat during processing and has poor responsiveness to the temperature control refrigerant. Therefore, when the above-described chiller device used for the lower electrode is simply adopted for the upper electrode, it takes a long time until the temperature of the upper electrode is stabilized after the processing of the substrate is started and high frequency power is applied to the upper electrode. This is a result. In this case, if the substrate is processed while the temperature of the upper electrode is unstable, the etching processing result becomes unstable, so it is necessary to delay the start of the processing of the substrate to be a product, which is a problem from the viewpoint of throughput. was there.

  The present invention has been made in view of such a point, and an object thereof is to stabilize the temperature of an electrode for plasma generation from the beginning of substrate processing.

In order to achieve the above object, the present invention provides a method for adjusting the temperature of an electrode to which high-frequency power for plasma generation is applied in a plasma processing apparatus for a substrate. A circulation path for circulating the medium; a first heat exchanger for exchanging heat with the sensible heat of the liquid refrigerant with respect to the heat medium that has passed through the electrodes in the circulation path; A second heat exchanger that exchanges heat with the latent heat of the refrigerant with respect to the heat medium that has passed through the heat exchanger, and a heater that heats the heat medium supplied to the inside of the electrode in the circulation path; And a bypass path is formed in the circulation path to circulate the heat medium that has passed through the heater, bypassing the plasma generating electrode, and circulation of the heat medium that has passed through the heater. A first through the electrode The first heat exchange is performed in an idle state in which a substrate is not processed by using a temperature adjusting device provided with a valve body that switches to a second circulation that passes through the bypass path without passing through the ring and the electrode. The temperature of the heat medium in the circulation path is adjusted by the second heat exchanger and the heater while the heater is stopped, and the temperature of the electrode is adjusted to a predetermined set temperature by the first circulation. At the start of the process and the processing of the substrate to which high frequency power is applied to the electrodes, the temperature of the heat medium is set using the first heat exchanger and the second heat exchanger while the heater is stopped. Lowering the set temperature of the electrode and maintaining the temperature of the electrode at the set temperature by the first circulation;
When the processing of the substrate is finished, the by circulating the heating medium through more the bypass passage to the second circulation, the heater in a state of stopping the first heat exchanger and the second heat exchanger The temperature of the heat medium is increased by using the valve body, the valve body is switched to the first circulation, and the heat medium is circulated by the first circulation so as to pass through the inside of the electrode. And a step of stabilizing the electrode at the set temperature by using the second heat exchanger and the heater while the first heat exchanger is stopped. The idle state here refers to a state in which substrate processing is not performed, for example, when a substrate lot is switched. The substrate processing start time is a time when the substrate processing is started from the idle state.

  According to the present invention, in the idle state where the substrate is not processed, the temperature of the electrode is adjusted to a predetermined set temperature in advance by the second heat exchanger and the heater that perform heat exchange by the latent heat of the refrigerant. . When the processing of the substrate is started, the temperature of the heat medium in the circulation path is rapidly cooled by both the first heat exchanger that exchanges heat by sensible heat of the liquid refrigerant and the second heat exchanger. To do. By so doing, the amount of heat generated by the high-frequency power for plasma generation is exhausted by the heat medium, and the temperature of the plasma generation electrode is continuously maintained at the set temperature. As a result, the temperature of the plasma generating electrode is stabilized from the beginning of the substrate processing, and the processing of the product substrate can be started at an early stage.

  The plasma generating electrode is an upper electrode, and the plasma processing apparatus includes a lower electrode on which a substrate is placed. The lower electrode is capable of applying high-frequency power, and the upper electrode in the idle state. The temperature difference ΔT between the predetermined temperature and the adjusted temperature of the heat medium at the start of the substrate processing is ΔT = k (aA + bB) × D / C (k: conversion factor from power to temperature, A: The high frequency power of the upper electrode, B: the high frequency power of the lower electrode, a: the coefficient indicating the ratio of the influence of the high frequency power of the upper electrode on the temperature of the upper electrode with respect to the influence of the entire high frequency power, b: the high frequency power of the lower electrode The coefficient indicating the ratio of the influence on the temperature of the upper electrode to the influence of the entire high-frequency power, C: processing time of one substrate, D: application time of high-frequency power during processing time C) Even .

  In the circulation path, a bypass path for circulating the heat medium bypassing the plasma generating electrode is formed, and when the substrate processing is completed, the heat medium is circulated through the bypass path. And increasing the temperature of the heat medium using the heater, and circulating the heat medium so as to pass through the electrode to stabilize the heat medium at the set temperature. May be.

  The temperature of the heat medium may be stabilized at the set temperature by alternately performing circulation of the heat medium that passes through the bypass path and circulation of the heat medium that passes through the inside of the electrode. . The liquid refrigerant may be water.

An electrode temperature adjusting device to which high-frequency power for plasma generation is applied in a plasma processing apparatus for a substrate, wherein the circuit passes through the electrode and circulates a heat medium to the electrode, , A first heat exchanger that exchanges heat with the sensible heat of the liquid refrigerant with respect to the heat medium that has passed through the electrode, and the heat medium that has passed through the first heat exchanger in the circulation path. A second heat exchanger that exchanges heat by the latent heat of the refrigerant, a heater that heats the heat medium supplied to the inside of the electrode in the circulation path, and an idle state in which the substrate is not processed, While the first heat exchanger is stopped, the temperature of the heat medium in the circulation path is adjusted by the second heat exchanger and the heater, and the temperature of the electrode is set to a predetermined value by the first circulation. The electrode is adjusted to the set temperature of At the start of processing of the substrate to which high-frequency power is applied, the temperature of the heat medium is set from the set temperature of the electrode using the first heat exchanger and the second heat exchanger while the heater is stopped. And a controller that maintains the temperature of the electrode at the set temperature by the first circulation, and bypasses the plasma generation electrode in the circulation path, A bypass path for circulating the passed heat medium is formed and the heat medium that has passed through the heater is circulated through the first circulation through the electrode and the second circulation through the bypass path without passing through the electrode. DOO valve body is provided for switching on, the control unit, when the processing of the substrate is finished, the by circulating the heating medium through more the bypass passage to the second circulation, the first heat exchanger And with the second heat exchanger stopped The temperature of the heat medium is increased using a heater, and in addition, the valve body is switched to the first circulation, and the heat medium is circulated by the first circulation so as to pass through the inside of the electrode. Then, the control is further performed to stabilize the electrode at the set temperature by using the second heat exchanger and the heater while the first heat exchanger is stopped.

  The plasma generating electrode is an upper electrode, the plasma processing apparatus includes a lower electrode on which a substrate is placed, a high frequency power can be applied to the lower electrode, and the control unit ΔT = k (aA + bB) × D / C (k: from electric power to temperature) ΔT = k (aA + bB) × D / C (k is the temperature difference between the predetermined temperature of the upper electrode in the state and the adjustment temperature of the heat medium at the start of the substrate processing Conversion coefficient, A: high frequency power of the upper electrode, B: high frequency power of the lower electrode, a: coefficient indicating the ratio of the influence of the high frequency power of the upper electrode on the temperature of the upper electrode with respect to the influence of the entire high frequency power, b: lower The coefficient indicating the ratio of the influence of the high frequency power of the electrode on the temperature of the upper electrode with respect to the influence of the entire high frequency power, C: processing time of one substrate, D: application time of high frequency power during processing time C) Calculate and set It may be.

  In the circulation path, a bypass path for circulating the heat medium bypassing the plasma generation electrode is formed, and the control unit passes through the bypass path when the substrate processing is completed. Circulating the heat medium, increasing the temperature of the heat medium using the heater, and additionally circulating the heat medium so as to pass through the inside of the electrode to stabilize the heat medium at the set temperature. You may make it make it.

  The controller stabilizes the temperature of the heat medium at the set temperature by alternately performing circulation of the heat medium passing through the bypass path and circulation of the heat medium passing through the inside of the electrode. You may do it. The liquid refrigerant may be water.

According to another aspect of the present invention, there is provided a plasma processing apparatus including the temperature adjusting device according to any one of claims 5 to 8 .

  According to the present invention, since the temperature of the upper electrode can be stabilized from the beginning of substrate processing, product substrate processing can be performed from the beginning, and throughput can be improved.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is an explanatory diagram showing an outline of the configuration of the plasma processing apparatus 1 and the temperature adjustment apparatus 100 according to the present embodiment.

  The plasma processing apparatus 1 is a capacitively coupled plasma etching apparatus having a parallel plate type electrode structure. The plasma processing apparatus 1 includes a substantially cylindrical processing container 10. A processing chamber S is formed in the processing container 10. The processing vessel 10 is formed of, for example, an aluminum alloy, and the inner wall surface is covered with an alumina film or an yttrium oxide film. The processing container 10 is grounded.

  A susceptor 12 is provided at the center bottom in the processing vessel 10 with an insulating plate 11 interposed. The susceptor 12 is formed in a substantially cylindrical shape, and the substrate W can be placed on the upper surface thereof. The susceptor 12 is made of, for example, an aluminum alloy and constitutes a lower electrode having a parallel plate type electrode structure.

  A ring-shaped refrigerant chamber 13 is formed inside the susceptor 12. The refrigerant chamber 13 communicates with a chiller unit (not shown) installed outside the processing container 10 through the pipes 13a and 13b. The refrigerant is circulated and supplied to the refrigerant chamber 13 through the pipes 13a and 13b, and the temperature of the substrate W on the susceptor 12 can be controlled by the circulation supply.

  Above the susceptor 12, an upper electrode 20 for plasma generation facing the susceptor 12 is provided. A plasma generation space is formed between the susceptor 12 and the upper electrode 20.

  The upper electrode 20 has a three-layer structure of, for example, an electrode plate 21, a dispersion plate 22, and a top plate 23. For example, a gas supply pipe 24 for introducing a processing gas for etching into the processing chamber S is connected to the central portion of the uppermost top plate 23. The gas supply pipe 24 is connected to a processing gas supply source 25. A substantially cylindrical dispersion plate 22 is provided below the top plate 23, for example, so that the processing gas introduced from the gas supply pipe 24 can be evenly dispersed. In the lower layer of the dispersion plate 22, for example, an electrode plate 21 facing the substrate W on the susceptor 12 is provided. A large number of gas ejection holes 21 a are formed in the electrode plate 21, and the processing gas dispersed by the dispersion plate 22 can be evenly ejected from the plurality of gas ejection holes 21 a.

  In the upper electrode 20, for example, inside the top plate 23, a ring-shaped flow path 30 through which a heat medium such as brine passes is formed. The flow path 30 constitutes a part of the circulation path 110 of the temperature adjusting device 100 described later. Further, for example, a temperature sensor 31 that measures the temperature of the upper electrode 20 that is a control target temperature for temperature control is provided inside the dispersion plate 22.

  A first high frequency power supply 41 is electrically connected to the upper electrode 20 via a matching unit 40. The first high frequency power supply 41 can output high frequency power having a frequency of, for example, 40 MHz or more, for example, 60 MHz. The first high frequency power supply 41 can apply high frequency power to the upper electrode 20 to generate plasma in the processing chamber S.

  A second high frequency power source 51 is electrically connected to the susceptor 12 via a matching unit 50. The second high-frequency power source 51 can output high-frequency power having a frequency of, for example, 2 MHz to 20 MHz, for example, 20 MHz. The second high frequency power supply 51 can apply high frequency power to the susceptor 12 and draw charged particles in the processing chamber S toward the substrate W.

  An exhaust pipe 60 communicating with an exhaust device (not shown) is connected to the side surface of the processing container 10. By exhausting from the exhaust pipe 60, the pressure in the processing container 10 can be reduced to a desired degree of vacuum.

  The plasma processing apparatus 1 is provided with an apparatus control unit 70 that controls operations of various specifications for performing an etching process such as the processing gas supply source 25, the first high-frequency power source 41, and the second high-frequency power source 51, for example. It has been. In addition, the measurement result by the temperature sensor 31 can be output to the device control unit 70.

  In the plasma etching process performed in the plasma processing apparatus 1, first, the substrate W is attracted and held on the susceptor 12. Next, the inside of the processing chamber S is reduced to a predetermined pressure by, for example, exhaust from the exhaust pipe 60. A processing gas is supplied from the upper electrode 20 into the processing chamber S. High frequency power is applied to the upper electrode 20 by the first high frequency power supply 41, and the processing gas in the processing chamber S is turned into plasma. Further, high frequency power is applied to the susceptor 12 by the second high frequency power supply 51, and charged particles in the plasma are induced to the substrate W side. The film on the substrate W is etched by the action of these plasmas. The etched substrate W is unloaded from the processing container 10 and the next substrate W is loaded.

  Next, the temperature adjustment device 100 that adjusts the temperature of the upper electrode 20 of the plasma processing apparatus 1 will be described.

  The temperature adjusting device 100 is configured to circulate a brine 110 so as to pass through the inside of the upper electrode 20 and to exchange heat by using the sensible heat of water as a liquid refrigerant for the brine flowing out from the upper electrode 20 in the circulation passage 110. Before supplying to the upper electrode 20, the first heat exchanger 111, the second heat exchanger 112 for exchanging the brine with latent heat in the circulation path 110, the electric heater 113 as a heater for heating the brine, It has a tank 114 for storing brine. The brine is a liquid heat exchange medium such as silicon oil, fluorine-based liquid, or ethylene glycol. In the circulation path 110, the first heat exchanger 111, the second heat exchanger 112, the electric heater 113, and the tank 114 are connected in series, and the upper electrode 20 → the first heat exchanger 111 → the second heat exchanger. The brine can be circulated in the order of the heat exchanger 112 → the electric heater 113 → the tank 114 → the upper electrode 20 (circulation E1 in FIG. 1).

  To the first heat exchanger 111, for example, a secondary refrigerant-side pipe line 120 for connecting and discharging water, which is a secondary refrigerant, into the first heat exchanger 111 is connected. The upstream side of the pipe 120 is connected to a water supply device (not shown), for example. By flowing water through the pipe line 120, the brine in the circulation path 110 can be cooled by sensible heat of water in the first heat exchanger 111. The pipe line 120 is provided with an opening / closing valve 121. By switching the opening / closing of the opening / closing valve 121, the cooling of the brine by the water of the first heat exchanger 111 can be turned on / off.

  The second heat exchanger 112 is an evaporator, and can cool the brine of the circulation path 110 by latent heat of, for example, an alternative chlorofluorocarbon as a secondary refrigerant, for example, hydrofluorocarbon (HFC). A circulation circuit 130 constituting a refrigerator is connected to the second heat exchanger 112. The circulation circuit 130 is provided with a compressor 131, a condenser 132, and an expansion valve 133. For example, a cooling water supply pipe 134 serving as a tertiary refrigerant is connected to the condenser 132. In the supply line 134, for example, a flow rate adjusting valve 135 is provided. For example, the cooling capacity in the second heat exchanger 112 can be adjusted by adjusting the amount of cooling water supplied to the condenser 132 by the flow rate adjusting valve 135.

  For example, the electric heater 113 can generate heat by supplying power from the heater power supply 140 to heat the brine in the circulation path 110.

  For example, a pump 150 is disposed in the tank 114, and brine stored in the tank 114 can be pumped to the upper electrode 20 side.

  For example, in the circulation path 110 between the tank 114 and the upper electrode 20, a bypass path 160 is formed in which the brine pumped from the tank 114 bypasses the upper electrode 20 and flows to the first heat exchanger 111 side. . By this bypass passage 160, the brine can be circulated in the order of the bypass passage 160 → the first heat exchanger 111 → the second heat exchanger 112 → the electric heater 113 → the tank 114 → the bypass passage 160 (in FIG. 1). Circulation E2). A three-way valve 161 is provided at a branch point of the bypass passage 160. With this three-way valve 161, it is possible to switch between the circulation E2 that passes through the bypass 150 without passing through the upper electrode 20, and the circulation E1 that passes through the upper electrode 20.

  The temperature adjusting device 100 includes, for example, an opening / closing valve 121 of the first heat exchanger 111, a flow rate adjusting valve 135 of the second heat exchanger 112, a heater power supply 140 of the electric heater 113, a pump 150 of the tank 114, and a three-way valve 161. A control unit 170 is provided for controlling operations of various specifications for performing temperature adjustment of the upper electrode 20 such as the above. The control unit 170 can communicate with the apparatus control unit 70 of the plasma processing apparatus 1, and can control the operation of the specifications based on information from the apparatus control unit 70.

  Next, the temperature adjustment process of the upper electrode 20 using the temperature adjustment device 100 will be described.

  When the plasma processing apparatus 1 is in an idle state before the lot processing of the substrate W is started, the temperature of the brine is adjusted in the circulation E1 in the circulation path 110, and the temperature of the upper electrode 20 is set in advance as shown in FIG. The temperature is adjusted to a predetermined set temperature H. This set temperature H is set to a temperature that stabilizes the upper electrode 20 during processing. In the temperature adjustment at this time, first, the temperature measurement result by the temperature sensor 31 of the upper electrode 20 shown in FIG. 1 is output to the device control unit 70 and is output from the device control unit 70 to the control unit 170. Based on the temperature measurement result, the controller 170 adjusts the flow rate adjustment valve 135 of the second heat exchanger 112 and the heater power supply 140 of the electric heater 113 so that the temperature of the upper electrode 20 becomes the set temperature H. The temperature of the brine in the circulation path 110 is adjusted. At this time, the opening / closing valve 121 of the first heat exchanger 111 is closed, and the temperature of the brine is adjusted by the second heat exchanger 112 and the electric heater 113. That is, the cooling of the brine is performed by the latent heat of the substitute chlorofluorocarbon of the second heat exchanger 112. As a result, the temperature of the brine in the circulation path 110 in the idle state is adjusted to a temperature slightly higher than the set temperature H due to the influence of heat radiation or the like.

  Then, in the plasma processing apparatus 1, when the idle state ends and the lot processing of the substrate W is started, the brine target temperature T in the circulation path 110 shown in FIG. 2 is set. For example, when the processing start information of the apparatus control unit 70 is input to the control unit 170, the target temperature T of the brine is set.

  The target temperature T is a temperature lower than the set temperature H of the upper electrode 20, and the temperature difference ΔT between the set temperature H and the target temperature T is obtained by the following equation (1).

  In Equation (1), k is a conversion factor from power to temperature, A is the high frequency power of the upper electrode 20, and B is the high frequency power of the susceptor 12. a is a coefficient indicating the degree of influence of the high-frequency power of the upper electrode 20 on the temperature of the upper electrode 20 with respect to the entire high-frequency power of the upper and lower electrodes, and b is the coefficient of the susceptor 12 with respect to the entire high-frequency power of the upper and lower electrodes. A coefficient indicating the degree of influence of the high frequency power on the temperature of the upper electrode 20 is shown. C is the processing time per substrate, and D is the application time of the high frequency power during the processing time C. As shown in FIG. 2, the processing time C is a time required for one substrate, for example, a combination of the time during which high-frequency power is applied and the replacement time of the substrate W. The calculation of the temperature difference ΔT and the setting of the target temperature T are performed by the control unit 170, for example.

  When the temperature difference ΔT is calculated and the target temperature T is set, the on-off valve 121 of the first heat exchanger 111 shown in FIG. 1 is opened, and the sensible heat of water in the first heat exchanger 111 and the first The brine in the circulation path 110 is rapidly cooled by the latent heat of the substitute chlorofluorocarbon in the second heat exchanger 112 and stabilized at the target temperature T. The heat generated by the lot processing of the substrate W being started and the high frequency power for plasma generation being applied to the upper electrode 20 is exhausted by the cooled brine, and the temperature of the upper electrode 20 is increased as shown in FIG. The set temperature H is maintained. Thereafter, the brine temperature is maintained at the target temperature T and the temperature of the upper electrode 20 is maintained at the set temperature H until the lot processing of the substrate W is completed. The timing when the brine is rapidly cooled by the first heat exchanger 111 and the second heat exchanger 112 is preferably, for example, the time when high-frequency power is first applied to the upper electrode 20 or just before that.

  Thereafter, when the lot processing is completed, the flow path on the bypass path 160 side of the three-way valve 161 shown in FIG. 1 is opened, and the brine is circulated so as to bypass the upper electrode 20 (circulation E2). At this time, for example, cooling by the first heat exchanger 111 and cooling by the second heat exchanger 112 are stopped, and the brine is heated by the electric heater 113 as shown in FIG. Thereafter, the three-way valve 161 is switched to the flow path on the upper electrode 20 side, and the warmed brine is circulated so as to pass through the upper electrode 20 (circulation E1). The three-way valve 161 is intermittently switched, and the brine circulation E1 passing through the upper electrode 20 and the shortcut circulation E2 bypassing the upper electrode 20 are alternately switched. Thereby, the temperature of the brine is returned to the temperature in the idle state. Further, the temperature of the upper electrode 20 that decreases immediately after the end of the lot processing is also restored to the set temperature H.

  According to the above embodiment, in the idle state, the temperature of the upper electrode 20 is adjusted in advance to the set temperature H that is stable during the processing, and the first heat exchanger 111 and the second heat exchanger 111 and the second heat treatment are performed at the start of the processing of the substrate W. The heat exchanger 112 is used to rapidly cool the brine to the target temperature T. Since the cooling by the first heat exchanger 111 is performed using water having a large heat capacity, even the upper electrode 20 having a large heat capacity and a large calorific value can be rapidly cooled, resulting from application of high-frequency power at the start of processing. The temperature rise of the upper electrode 20 can be suppressed. As a result, even if the processing of the substrate W is started, the temperature of the upper electrode 20 is maintained at the set temperature H, and the processing of the substrate W for products can be performed from the beginning.

  In addition, the cooling temperature ΔT of the brine is obtained by the equation (1) in consideration of the ratio of the high frequency power of the upper electrode 20 and the susceptor 12 and the temperature effect of each high frequency power on the upper electrode 20. An accurate temperature for maintaining the set temperature H of 20 can be calculated.

  When the lot processing was completed, the brine was circulated by a shortcut through the bypass path 160 to quickly raise the brine temperature, and then the bypass path 160 was closed and the brine was allowed to flow to the upper electrode 20. Since this is repeated alternately, the temperature of the upper electrode 20 that temporarily decreases at the end of the processing of the substrate W can be restored to the set temperature H in a short time.

  In the plasma processing apparatus 1, a plurality of etching processes may be continuously performed on one substrate W. At this time, the high frequency power is applied to the upper electrode 20 a plurality of times with respect to the substrate W. In this case, in obtaining the cooling temperature ΔT of the brine by the equation (1), for example, as shown in FIG. 4, the application time D of the high frequency power is the application time D of each high frequency power with respect to the processing time C of one substrate W. You may obtain | require by integrating | accumulating time D1, D2, D3. When the output of the high frequency power at each time is different, the high frequency power A of the upper electrode 20 and the high frequency power B of the susceptor 12 may be an average value of the high frequency power of a plurality of times.

  The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such an example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the spirit described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs. For example, in the above-described embodiment, the temperature control of the upper electrode 20 of the plasma processing apparatus 1 that performs the etching is performed. However, the temperature control of the upper electrode in the plasma processing apparatus that performs a plasma process other than the etching process, for example, a film forming process. It may be. The electrode for temperature control is not limited to the upper electrode, and may be the lower electrode as long as it is an electrode for plasma generation. Furthermore, the liquid refrigerant of the first heat exchanger 111 may use water in a disposable manner, or may be temperature-controlled so as to keep the temperature constant by circulating water. In the case where the temperature is circulated and used, brine may be used as the liquid refrigerant. The refrigerant of the second heat exchanger 112 may use ammonia, air, carbon dioxide, hydrocarbon-based gas, or the like, in addition to the substitute chlorofluorocarbon HFC.

  The present invention is useful for stabilizing the temperature of the upper electrode from the start of the plasma treatment.

It is explanatory drawing which shows the outline of a structure of the plasma processing apparatus and temperature control apparatus concerning this Embodiment. It is a graph which shows the temperature change of the upper electrode and brine from the idle state to the time of lot processing, and the ON / OFF timing of the upper electrode. It is a graph which shows the temperature change of the upper electrode and brine at the time of completion | finish of lot processing, the ON / OFF timing of an upper electrode, and the switching of the circulation of a brine. It is explanatory drawing which shows the processing time in case the process of a board | substrate covers multiple steps, and high frequency electric power application time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 20 Upper electrode 70 Apparatus control part 100 Temperature control apparatus 110 Circulation path 111 1st heat exchanger 112 2nd heat exchanger 113 Electric heater 160 Bypass path 170 Control part W board | substrate

Claims (9)

A method for adjusting the temperature of an electrode to which high-frequency power for plasma generation is applied in a substrate plasma processing apparatus,
A circulation path that passes through the inside of the electrode and circulates a heat medium to the electrode;
A first heat exchanger that exchanges heat with the sensible heat of the liquid refrigerant with respect to the heat medium that has passed through the electrode in the circulation path;
A second heat exchanger for exchanging heat by latent heat of a refrigerant with respect to the heat medium that has passed through the first heat exchanger in the circulation path;
A heater that heats the heat medium supplied to the inside of the electrode in the circulation path, and the heat medium that has passed through the heater bypassing the electrode for plasma generation in the circulation path. A valve body in which a bypass path for circulation is formed and the circulation of the heat medium that has passed through the heater is switched between a first circulation that passes through the electrode and a second circulation that passes through the bypass path without passing through the electrode Using the temperature control device provided with
In the idle state where the substrate is not processed, the temperature of the heat medium in the circulation path is adjusted by the second heat exchanger and the heater while the first heat exchanger is stopped, Adjusting the temperature of the electrode to a predetermined set temperature by a first circulation;
At the start of processing of the substrate to which high frequency power is applied to the electrode, the temperature of the heating medium is set to the temperature of the electrode using the first heat exchanger and the second heat exchanger in a state where the heater is stopped. Lowering below a set temperature and maintaining the temperature of the electrode at the set temperature by the first circulation;
When the processing of the substrate is finished, the by circulating the heating medium through more the bypass passage to the second circulation, the heater in a state of stopping the first heat exchanger and the second heat exchanger The temperature of the heat medium is increased by using the valve body, the valve body is switched to the first circulation, and the heat medium is circulated by the first circulation so as to pass through the inside of the electrode. And a step of stabilizing the electrode at the set temperature using the second heat exchanger and the heater while the first heat exchanger is stopped. The plasma generating electrode is an upper electrode,
The plasma processing apparatus includes a lower electrode on which a substrate is placed,
High frequency power can be applied to the lower electrode,
The temperature difference ΔT between the predetermined temperature of the upper electrode in the idle state and the adjustment temperature of the heat medium at the start of processing of the substrate is:
ΔT = k (aA + bB) × D / C
(K: conversion factor from power to temperature, A: high frequency power of upper electrode, B: high frequency power of lower electrode, a: influence of high frequency power of upper electrode on temperature of upper electrode A coefficient indicating a ratio, b: a coefficient indicating a ratio of the influence of the high-frequency power of the lower electrode on the temperature of the upper electrode with respect to the influence of the entire high-frequency power, C: processing time of one substrate, D: high frequency during the processing time C The temperature adjustment method according to claim 1, wherein the temperature adjustment method is set by an expression of power application time. The temperature of the heat medium is stabilized at the set temperature by alternately performing circulation of the heat medium that passes through the bypass passage and circulation of the heat medium that passes through the inside of the electrode. The temperature adjustment method according to claim 1 or 2. The temperature adjustment method according to claim 1, wherein the liquid refrigerant is water. An electrode temperature adjusting device to which a high frequency power for plasma generation is applied in a substrate plasma processing apparatus,
A circulation path that passes through the inside of the electrode and circulates a heat medium to the electrode;
A first heat exchanger that exchanges heat with the sensible heat of the liquid refrigerant with respect to the heat medium that has passed through the electrode in the circulation path;
A second heat exchanger for exchanging heat by latent heat of a refrigerant with respect to the heat medium that has passed through the first heat exchanger in the circulation path;
A heater for heating a heat medium supplied to the inside of the electrode in the circulation path;
In the idle state where the substrate is not processed, the temperature of the heat medium in the circulation path is adjusted by the second heat exchanger and the heater while the first heat exchanger is stopped, The temperature of the electrode is adjusted to a predetermined set temperature by a first circulation, and the heater is stopped at the start of processing of a substrate to which high-frequency power is applied to the electrode. A controller that lowers the temperature of the heating medium below the set temperature of the electrode using a second heat exchanger, and maintains the temperature of the electrode at the set temperature by the first circulation;
A bypass path is formed in the circulation path to circulate the heat medium that has passed through the heater, bypassing the electrode for plasma generation, and circulation of the heat medium that has passed through the heater is routed to the circulation path. A valve body is provided for switching between a first circulation passing through and a second circulation passing through the bypass without passing through the electrode;
Wherein, when the processing of the substrate is finished, the by circulating the heating medium through more the bypass passage to the second circulation was stopped the first heat exchanger and the second heat exchanger In the state, the temperature of the heat medium is increased using the heater, and in addition, the valve body is switched to the first circulation, and the heat medium is passed through the electrode so as to pass through the first circulation. , And further controlling to stabilize the electrode at the set temperature using the second heat exchanger and the heater while the first heat exchanger is stopped. Temperature control device. The plasma generating electrode is an upper electrode,
The plasma processing apparatus includes a lower electrode on which a substrate is placed,
High frequency power can be applied to the lower electrode,
The control unit calculates a temperature difference ΔT between a predetermined temperature of the upper electrode in the idle state and an adjustment temperature of the heat medium at the start of processing of the substrate,
ΔT = k (aA + bB) × D / C
(K: conversion factor from power to temperature, A: high frequency power of upper electrode, B: high frequency power of lower electrode, a: influence of high frequency power of upper electrode on temperature of upper electrode A coefficient indicating the ratio, b: a coefficient indicating the ratio of the influence of the high-frequency power of the lower electrode on the temperature of the upper electrode with respect to the influence of the entire high-frequency power, C: the processing time of one substrate, D: the high frequency during the processing time C 6. The temperature adjusting device according to claim 5, wherein the temperature adjusting device is calculated and set by an expression of power application time. The controller stabilizes the temperature of the heat medium at the set temperature by alternately performing circulation of the heat medium passing through the bypass path and circulation of the heat medium passing through the inside of the electrode. The temperature control device according to claim 5 or 6, wherein The temperature adjusting device according to claim 5, wherein the liquid refrigerant is water. The plasma processing apparatus provided with the temperature control apparatus in any one of Claims 5-8.

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