JP4551256B2 - Mounting table temperature control device, mounting table temperature control method, processing device, and mounting table temperature control program - Google Patents

Description

  The present invention relates to a technique for controlling the temperature of a mounting table on which an object to be processed is mounted, and in particular, a mounting table temperature control method and apparatus capable of variously selecting or controlling the temperature or temperature distribution on the mounting table, and the same The present invention relates to a processing apparatus using the.

  For example, in microfabrication of a semiconductor substrate or liquid crystal panel using plasma, it is very important to control the temperature distribution of the substrate to be processed, the plasma density distribution on the substrate, the distribution of reaction products, and the like. If these distribution controls are not performed properly, process uniformity on the substrate surface cannot be ensured, and the manufacturing yield of semiconductor devices or display devices decreases.

  In general, a mounting table or a supporting table for mounting a substrate to be processed in a chamber of a plasma processing apparatus includes a function of a high-frequency electrode that applies a high frequency to a plasma space and a holding unit that holds the substrate by electrostatic adsorption or the like. And a function of a hot plate that controls the substrate to a predetermined temperature by heat transfer. Regarding the hot plate function, it is desired that the distribution of heat input characteristics to the substrate due to non-uniformity of radiant heat from plasma and chamber walls and the heat distribution by the substrate support structure can be appropriately corrected.

  Conventionally, in order to control the temperature of this type of mounting table, a refrigerant flow path or passage through which the refrigerant flows is provided inside the mounting table, and the temperature-controlled refrigerant is circulated and supplied to the refrigerant path inside the mounting table. Many methods are used. In general, since the chiller apparatus is installed in a utility room different from the clean room in which the processing apparatus is installed, the length of the pipe connecting the chiller apparatus and the mounting table in the chamber is at least several meters, and 10 m It is not uncommon to exceed.

Recently, with the miniaturization and diversification of processing in plasma processing, various profiles have been required for the temperature distribution of the mounting table. However, from the viewpoint of achieving in-plane uniformity of the process on the substrate, most applications require an appropriate balance of temperature control between the central portion and the peripheral portion of the mounting table. As a conventional technique for meeting such demands, independent refrigerant flow paths are provided at the center and the peripheral part of the mounting table, respectively, and refrigerants individually controlled by two chiller devices are circulated through both refrigerant flow paths. There is known a technique (see, for example, Patent Document 1) in which the temperature is individually controlled for the central portion and the peripheral portion of the mounting table.
Japanese Patent Laid-Open No. 06-37056

  However, the prior art as described above has not only cost and space efficiency disadvantages due to the need for two chiller devices, but also has a problem of poor responsiveness of temperature control. That is, since the heat capacity of the chiller device itself is very large, it is difficult to rapidly change the temperature of the refrigerant, and the piping (flow path) to the mounting table is considerably long as described above, so that high-speed heating / cooling is realized. It is not possible. In the field of recent processes such as plasma etching, a method of continuously processing a multilayer film on a substrate to be processed in a single chamber is required instead of the conventional multi-chamber method. In order to realize this single chamber system, a technique for changing the temperature of the substrate in a short time at the change of the film to be processed, that is, a technique that enables high-speed temperature raising / lowering of the mounting table has become essential.

  A method of controlling the temperature distribution on the mounting table by incorporating a heating element such as a heater or thermoelectric element in the mounting table is also conceivable. However, this method increases the running cost, affects the high-frequency electrode function, and complicates the internal structure of the mounting table, and is not practical.

  The present invention has been made in view of the problems or problems of the prior art as described above, and controls the temperature or temperature distribution of the mounting table with a relatively small and simple configuration with various or high precision, It is another object of the present invention to provide a mounting table temperature control method and a mounting table temperature control program that are capable of high-speed raising and lowering the temperature of the mounting table.

  Another object of the present invention is to provide a processing apparatus that improves the uniformity and diversity of processing on an object to be processed through temperature control of a mounting table.

In order to achieve the above object, the mounting table temperature control apparatus of the present invention controls the temperature of the mounting table on which the object to be processed is placed in a chamber of a processing apparatus that performs a desired process on the object to be processed under reduced pressure. A mounting table temperature control device for controlling the first and second refrigerant passages having individual inlets and outlets provided in the mounting table, and refrigerant in the first and second refrigerant passages. In order to circulate and supply, the outlet connected to the inlet of the first refrigerant channel via the first channel, and connected to the outlet of the second refrigerant channel via the second channel A refrigerant circulator that returns the refrigerant returned to the return port to a reference temperature and sends it out from the delivery port, and the temperature of the refrigerant in the middle of the first flow path from the reference temperature. A refrigerant temperature control unit for raising or lowering the temperature to a desired set temperature, and the first refrigerant; A first port connected to the outlet of the path via a third flow path, and a first flow path branch point provided upstream of the refrigerant temperature control unit of the first flow path. A second port connected through the fourth flow path, a third port connected to the inlet of the second refrigerant passage through the fifth flow path, and the second flow path. And a fourth port connected to the second flow path branch point via the sixth flow path, and the flow path between the first, second, third and fourth ports A flow path switching unit capable of conducting, blocking, and changing, and a flow path control unit that controls conduction, blocking, or change of the flow path in the flow path switching unit.

  In the above configuration, the function of controlling the temperature of the refrigerant circulated and supplied to the first and second refrigerant passages by the refrigerant circulator to the reference temperature, and the refrigerant temperature control unit provided in the middle of the first flow path The function of raising or lowering the temperature of the refrigerant from the reference temperature by the combination of the function of switching the connection relationship of the first and second refrigerant passages to the refrigerant circulator by the flow path switching unit is combined with the first and second refrigerants. It is possible to select various temperatures of the refrigerant respectively supplied to the passages, and it is possible to control the temperature or temperature distribution of the mounting table in various and precise manners. One refrigerant circulator is sufficient.

  According to a preferred aspect of the present invention, the flow path switching unit includes the first on-off valve connected between the first port and the third port, the first port, and the first port. 4, a second on-off valve connected between the four ports, a third on-off valve connected between the second port and the third port, the second port, and the second And a fourth on-off valve connected between the four ports, and the flow path control unit controls on / off of the first, second, third and fourth on-off valves. In this configuration, each on-off valve may be turned on / off independently, or may be complementarily performed with other on-off valves. As an example, the first and third on-off valves can be configured with normally open valves, and the second and fourth on-off valves can be configured with normally closed valves. Alternatively, the flow path switching unit includes a first directional switching valve connected between the first port and the third and fourth ports, a second port, and the third and fourth ports. And a second direction switching valve connected between them, and the flow path control unit may control the respective flow path states in the first and second direction switching valves.

  According to a preferred aspect, the refrigerant temperature control unit detects the temperature of the in-line heater attached to the first flow path and the refrigerant in the first flow path downstream of the in-line heater. A temperature sensor and a temperature control unit that controls the amount of heat generated by the in-line heater so that the refrigerant temperature detected by the sensor coincides with the set temperature. According to such a configuration, it is possible to efficiently perform rapid temperature rising and cooling by efficiently performing heating or heat absorption on the refrigerant flowing through the first flow path in a space-saving manner. In order to enhance the effect of rapid temperature increase / decrease, the in-line heater preferably heats the refrigerant in the first flow path at a position close to the mounting table.

  According to a preferred aspect, the flow rate control valve for variably controlling the flow rate of the refrigerant is provided downstream of the first flow path branch point of the first pipe. This flow control valve may be, for example, a manually operated or machine operated variable throttle valve. In general, when the heating amount or endothermic amount of the refrigerant flowing in the pipe is kept constant, the flow rate and the refrigerant temperature rise and fall are inversely proportional to each other. The smaller the flow rate (throttle), the higher the refrigerant temperature. The temperature can be raised and lowered. Thus, by combining the refrigerant flow control by the flow control valve and the heating or heat absorption control by the heating unit or the heat absorption unit, the temperature of the refrigerant can be increased or decreased from the reference temperature to a desired set value quickly and accurately. .

  According to a preferred aspect, the first refrigerant passage and the second refrigerant passage are disposed concentrically with respect to the center of the mounting table, and the first refrigerant passage is particularly preferably provided. The second refrigerant passage is provided in the peripheral region of the mounting table, and is provided in the central region of the mounting table. Moreover, as a preferable aspect, the refrigerant circulator includes a pump for circulating the refrigerant, a refrigeration unit for freezing the refrigerant immediately after returning, and a heating unit for heating the refrigerant after freezing to a predetermined reference temperature. Have

The first stage temperature control method placement in terms of the present invention, first and provided in the mounting table mounting the object to be processed in a chamber of the processing apparatus for performing a desired process on a target object in vacuo 2 is a mounting table temperature control method for controlling the temperature of the mounting table by circulating and supplying a refrigerant from a refrigerant circulator to the refrigerant passage of the first, between the outlet and the return port of the refrigerant circulator. A refrigerant passage and the second refrigerant passage are connected in parallel, and a part of the refrigerant sent out at a reference temperature from the refrigerant circulator is raised or lowered from the reference temperature to a desired set temperature, and then the first A first temperature control mode in which the temperature of the mounting table is controlled by flowing into the first refrigerant passage and the rest flowing through the second refrigerant passage substantially at the reference temperature; and the outlet of the refrigerant circulator; The first refrigerant passage and the second refrigerant between the return port And a part of the refrigerant sent from the refrigerant circulator is allowed to flow through the first refrigerant passage substantially at the reference temperature, and the rest is substantially kept at the reference temperature. A second temperature control mode for controlling the temperature of the mounting table through the second refrigerant passage, and the first temperature control mode and the second temperature according to the processing conditions of the object to be processed. Switch between control modes.

According to this method, in the first temperature control mode, one refrigerant circulator is used, the refrigerant at the reference temperature is caused to flow through the second refrigerant passage, and the first refrigerant passage is set to be different from the reference temperature. It is possible to flow a refrigerant having a temperature and change the temperature distribution of the mounting table. In addition, since only the refrigerant that flows through the first refrigerant passage needs to be heated or cooled immediately before, the heating or cooling efficiency is high, and rapid temperature rise or temperature drop is possible.

  In the second temperature control mode, the refrigerant from the refrigerant circulator is supplied to both the first and second refrigerant passages at the reference temperature, and a substantially flat temperature distribution corresponding to the reference temperature is provided on the mounting table. Obtainable. In the mode switching, the temperature or temperature distribution of the mounting table (and thus the object to be processed) is changed between the first steady state corresponding to the first temperature control mode and the second steady state corresponding to the second temperature control mode. Thus, the transition can be made in a shorter time than the rapid temperature increase or the rapid temperature decrease.

  According to a preferred aspect, the first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and the refrigerant circulated by the refrigerant circulator A third temperature control mode is further provided in which a part of the temperature is raised or lowered from the reference temperature to a desired set temperature and then sequentially flowed through the first and second refrigerant passages, and the rest is bypassed to control the temperature of the mounting table. And switching between the first temperature control mode, the second temperature control mode, and the third temperature control mode according to the processing conditions of the object to be processed.

  In the third temperature control mode, a refrigerant having a set temperature different from the reference temperature is supplied to both the first and second refrigerant passages, and a substantially flat temperature distribution corresponding to the set temperature is obtained on the mounting table. be able to. In the mode switching, the temperature or temperature distribution of the mounting table (and thus the object to be processed) is changed between a first steady state corresponding to the first temperature control mode and a second steady state corresponding to the second temperature control mode. The transition to the third steady state corresponding to the third temperature control mode can be made in a shorter time than the rapid temperature increase or the rapid temperature decrease. In particular, in switching to the third temperature control mode, variable control of the refrigerant supply flow rate to both refrigerant passages can be performed at high speed and stably by the action of the bypass passages.

  Further, according to a preferred aspect, the first refrigerant passage and the second refrigerant passage are connected in series between the outlet and return port of the refrigerant circulator, and the refrigerant sent from the refrigerant circulator is connected. A fourth temperature control mode for controlling the temperature of the mounting table by sequentially flowing all of them from the reference temperature to a desired set temperature and then flowing them sequentially through the first and second fluid passages; Switching between the first temperature control mode, the second temperature control mode, and the fourth temperature control mode is performed according to the processing conditions.

  In the fourth temperature control mode, a refrigerant having a set temperature different from the reference temperature is supplied to both the first and second refrigerant paths, and a substantially flat temperature distribution corresponding to the set temperature is obtained on the mounting table. be able to. In the mode switching, the temperature or temperature distribution of the mounting table (and thus the object to be processed) is changed between a first steady state corresponding to the first temperature control mode and a second steady state corresponding to the second temperature control mode. The transition to the fourth steady state corresponding to the fourth temperature control mode can be made in a shorter time than the rapid temperature increase or the rapid temperature decrease.

Further, according to a preferred aspect, the first refrigerant passage and the second refrigerant passage are connected in series between the outlet and return port of the refrigerant circulator, and the refrigerant sent from the refrigerant circulator is connected. A fifth temperature control mode is further provided for controlling the temperature of the mounting table by sequentially flowing a part of the first and second refrigerant passages with the reference temperature substantially unchanged and bypassing the rest, Switching between the first temperature control mode , the second temperature control mode, and the fifth temperature control mode is performed according to the processing conditions.

In the fifth temperature control mode, the refrigerant from the refrigerant circulator is supplied to both the first and second refrigerant passages at the reference temperature, and a substantially flat temperature distribution corresponding to the reference temperature is provided on the mounting table. Obtainable. Further, the supply flow rate of the refrigerant can be variably controlled at high speed by the action of the bypass path. In the mode switching, the temperature or temperature distribution of the mounting table (and thus the object to be processed) is changed between a first steady state corresponding to the first temperature control mode and a second steady state corresponding to the second temperature control mode. it can be transferred in a shorter time than the rapid thermal or fast cooling between the fifth steady state corresponding to the fifth temperature control mode.

According to a preferred aspect, the first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and the refrigerant circulated by the refrigerant circulator There is further provided a sixth temperature control mode for controlling the temperature of the mounting table by sequentially flowing all through the first and second refrigerant passages while maintaining substantially the reference temperature, and the first temperature control mode is provided according to the processing conditions of the object to be processed. The temperature control mode , the second temperature control mode, and the sixth temperature control mode are switched.

In the sixth temperature control mode, the refrigerant from the refrigerant circulator is supplied to both the first and second refrigerant passages at the reference temperature, and a substantially flat temperature distribution corresponding to the reference temperature is provided on the mounting table. Obtainable. In the mode switching, the temperature or temperature distribution of the mounting table (and thus the object to be processed) is changed between a first steady state corresponding to the first temperature control mode and a second steady state corresponding to the second temperature control mode. it can be transferred in a shorter time than the rapid thermal or fast cooling between the sixth steady state corresponding to the sixth temperature control mode.

The second stage temperature control method placement in terms of the present invention, first and provided in the mounting table mounting the object to be processed in a chamber of the processing apparatus for performing a desired process on a target object in vacuo A mounting table temperature control method for controlling the temperature of the mounting table by circulating and supplying a refrigerant from a refrigerant circulator to a second refrigerant passage, wherein the first circulator between the outlet and the return port of the refrigerant circulator. The refrigerant passage and the second refrigerant passage are connected in parallel, and a part of the refrigerant sent out from the refrigerant circulator at a reference temperature is raised or lowered from the reference temperature to a desired set temperature. A first temperature control mode for controlling the temperature of the mounting table by flowing through the first refrigerant passage and flowing the remainder through the second refrigerant passage substantially at the reference temperature; and an outlet of the refrigerant circulator And the first refrigerant passage and the second refrigerant A medium passage is connected in parallel, a part of the refrigerant sent from the refrigerant circulator is caused to flow to the first refrigerant passage substantially at the reference temperature, and the rest is substantially kept at the reference temperature. A second temperature control mode for controlling the temperature of the mounting table by flowing through the second refrigerant passage, and the first refrigerant passage and the second between the outlet and the return port of the refrigerant circulator. A refrigerant passage is connected in series, and a part of the refrigerant sent from the refrigerant circulator is raised or lowered from the reference temperature to a desired set temperature, and then sequentially flowed through the first and second refrigerant passages. A third temperature control mode for controlling the temperature of the mounting table by bypassing the rest, and the first refrigerant passage and the second refrigerant passage between the outlet and the return port of the refrigerant circulator All of the refrigerant sent out from the refrigerant circulator A fourth temperature control mode for controlling the temperature of the mounting table sequentially poured into the first and second fluid passage from the raised or lowered to a desired set point temperature than the reference temperature, feeding of the coolant circulator The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port, and a part of the refrigerant sent from the refrigerant circulator is substantially kept at the reference temperature. The first and second refrigerant passages are sequentially flowed, and the rest is bypassed to control the temperature of the mounting table, and the first temperature control mode is between the first outlet and the return outlet of the refrigerant circulator. The refrigerant passage and the second refrigerant passage are connected in series, and all of the refrigerant sent from the refrigerant circulator is caused to flow through the first and second refrigerant passages in sequence at substantially the reference temperature. In the sixth temperature control mode for controlling the temperature of the mounting table, Of these, switching between the first mode or the second mode and the third mode, the fourth mode, the fifth mode, or the sixth mode is performed. Do.

Also in the second mounting table temperature control method, as in the mounting table temperature control method in the first aspect , the temperature distribution of the mounting table can be varied in various ways, and the rapid temperature increase or the rapid temperature decrease. Can be easily realized.

  A processing apparatus according to the present invention includes a depressurizable chamber that houses a mounting table on which an object to be processed is mounted, a mounting table temperature control apparatus according to the present invention, an exhaust unit for exhausting the inside of the chamber, and the chamber. A processing gas supply unit for supplying the processing gas. In the configuration of such a processing apparatus, the temperature or temperature distribution of the object to be processed can be controlled variously or with high accuracy via the mounting table by the mounting table temperature control apparatus of the present invention.

  In the processing apparatus, according to a preferred aspect, a plasma source for generating or supplying plasma of the processing gas in the chamber, or a first high-frequency power supply for supplying a first high-frequency power to the mounting table. Parts are provided. Further, a configuration in which a counter electrode facing the mounting table in the chamber and a second high-frequency power feeding unit for feeding a second high frequency to the counter electrode is also possible.

  Further, according to a preferred aspect, the electrostatic chuck for electrostatically attracting the object to be processed to the mounting table, and heat transfer gas supplying heat transfer gas between the back surface of the object to be processed and the mounting surface And a gas supply path.

  As a preferred aspect, the processing apparatus heats the refrigerant flowing through the first flow path by the refrigerant temperature control unit before the desired plasma processing is started on the object to be processed. The coolant temperature control unit raises the temperature of the object to the set processing temperature for processing and keeps the temperature of the object to be processed substantially at the set processing temperature from the start of the plasma processing to the end of the processing thereafter. Thus, the heating of the refrigerant flowing through the first flow path is gradually weakened. In other words, it is possible to correct fluctuation (increase) in the temperature of the workpiece due to heat input from the plasma using the high-speed temperature rising / lowering function by the refrigerant temperature control unit, and temperature management and reproducibility of single wafer plasma processing. Yield can be improved.

  In the present invention, the reference temperature of the refrigerant sent from the refrigerant circulator does not necessarily have to be strictly constant or need to be one temperature value, and has a certain fluctuation range or range. Good.

  According to the mounting table temperature control device, the mounting table temperature control method, or the mounting table temperature control program of the present invention, the configuration and operation of the mounting table enable the mounting table with a relatively small and simple configuration that is highly practical. It is possible to control the temperature or temperature distribution in various or high accuracy, and to enable the temperature of the mounting table to be raised and lowered quickly. Moreover, according to the processing apparatus of this invention, the uniformity and diversity of the process with respect to a to-be-processed object can be improved through the temperature control of a mounting base by the above structures and effect | actions.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  In FIG. 1, the structure of the mounting base temperature control apparatus in one Embodiment of this invention is shown. This mounting table temperature control apparatus typically mounts a semiconductor wafer W for the purpose of controlling the temperature or temperature distribution of a substrate to be processed, such as a semiconductor wafer W, to be processed in a chamber 10 that can be depressurized. It is a device that controls the temperature or temperature distribution of the mounting table 12. As a basic configuration, the refrigerant path, the chiller unit 14, the heating unit 16, the flow path switching unit 18, and the piping (26, 28, 30) inside the mounting table 12. , 32, 58, 60, etc.) and the controller 20.

  Inside the mounting table 12, a plurality of systems, for example two systems, are provided for passage of the refrigerant. Typically, refrigerant passages 22 and 24 having separate inlets and outlets are provided in a central region including the center of the mounting table 12 and a peripheral region including an edge, respectively. These refrigerant passages 22 and 24 are formed in, for example, concentric circles or spirals (vortices) so that the temperature of the refrigerant can be transmitted to the respective regions without any problem. The refrigerant passage 22 in the central region preferably has an inlet 22a at the center of the spiral and an outlet 22b at the outer periphery of the spiral.

  The inlet 22a of the refrigerant passage 22 is connected to the delivery port 14a of the chiller unit 14 via a pipe 26, and the outlet 22b of the refrigerant passage 22 has a pipe 28 connected to the port (first inlet) 18a of the flow path switching unit 18. Connected through. On the other hand, the inlet 24 a of the refrigerant passage 24 is connected to a port (first outlet) 18 c of the flow path switching unit 18 via a pipe 30, and the outlet 24 b of the refrigerant passage 24 is piped to the return port 14 b of the chiller unit 14. 32 is connected.

  The chiller unit 14 has a function of circulating and supplying the refrigerant to both refrigerant passages 22 and 24 of the mounting table 12. For example, a pump 34 for circulating the refrigerant and the refrigerant immediately after returning to the return port 14 b are used. A refrigerator 36 for freezing and a heater 38 for heating the refrigerant after freezing to a predetermined base temperature (reference temperature) are provided (FIG. 5). In general, the chiller unit 14 is installed at a location far from the mounting table 12, and the pipes 26 and 32 connecting the two are also considerably long (for example, 5 m or more). The operation of each part in the chiller unit 14 and the refrigerant circulation supply operation of the entire unit are controlled by the controller 20.

  Note that the base temperature of the refrigerant sent out from the refrigerant circulator is not necessarily strictly constant, and is not maintained at one temperature value, and has a certain fluctuation range within an allowable range (for example, 5 It is common to have ° C).

  The heating unit 16 has a refrigerant temperature increasing function that heats the refrigerant in the middle of the pipe 26 and raises the refrigerant temperature from the base temperature to a desired set temperature, and is arranged at a position as close as possible to the mounting table 12. And an in-line heater 40 attached to the in-line heater 40 and a power source 42 for supplying electric power to the in-line heater 40. The in-line heater 40 is preferably not only one having a high temperature heating function, but also preferably one having a physical strength capable of withstanding the pressure of the refrigerant pumped from the chiller unit 14 through the pipe 26 over a long distance. An induction heating type heater as shown in FIG.

  In the configuration example of FIG. 2, the in-line heater 40 accommodates a coiled SUS heating element tube 48 that forms part or one section of the pipe 26 in the insulating tube 46, and is composed of a conductive wire around the insulating tube 46. The work coil 50 is fitted or mounted. When a high-frequency alternating current is passed from the power source 42 to the work coil 50, an alternating magnetic flux is generated in the insulating cylinder 46, and this alternating magnetic flux generates an induced voltage in the SUS heating element tube 48 to cause an induced current to flow. Tube 48 generates Joule heat. The refrigerant flowing through the pipe is heated by the heat generated by the SUS heating element pipe 48. Unlike a glass tube such as a heating lamp, the SUS heating element tube 48 has a very high physical strength and can sufficiently withstand the pressure of the medium.

  In FIG. 1, in this embodiment, in order to increase the accuracy of the refrigerant temperature increasing function, the heating unit 16 detects a temperature of the refrigerant downstream of the in-line heater 40, and an output signal of the temperature sensor 52. A temperature controller 54 is provided for controlling the power supplied to the power source 42 and the heat generation amount of the heater 40 so that the refrigerant temperature matches the set value in accordance with the (temperature detection signal).

  Further, in order to further increase the rapid heating, for example, a manual operation type or a mechanical operation type (for example, an electromagnetic valve type) is used to variably control the flow rate of the refrigerant supplied from the pipe 26 to the refrigerant passage 22 in the central region of the mounting table. Further, a flow control valve 44 including a variable throttle valve of a motor drive type, an air operated type, or the like is also provided. In addition, a flow rate measuring device or flow rate sensor 56 is attached to the pipe 26 in order to increase the accuracy of flow rate control.

  FIG. 3 shows a relationship (one example) between the flow rate and the refrigerant temperature rise and fall when the heating value of the in-line heater 40 is kept constant in the heating unit 16. As shown in the figure, the flow rate and the refrigerant temperature rise and fall are inversely proportional to each other, and the temperature of the refrigerant can be significantly increased as the flow rate is reduced (squeezed). Thus, by combining the refrigerant flow control by the flow control valve 44 and the heating control by the in-line heater 40, the temperature of the refrigerant can be increased or decreased quickly and accurately from the base temperature to a desired set value. In addition, since the in-line heater 40 is disposed at a position close to the mounting table 12, it is possible to transmit the rapid temperature rise and fall of the refrigerant to the mounting table 12 as it is with a very small time constant. The temperature can be raised and lowered to a desired set value at high speed in time. The operation of each part in the heating unit 16 and the refrigerant raising / lowering temperature operation of the entire unit are controlled by the controller 20.

In FIG. 1, the flow path switching unit 18 includes two ports (second inlet and second outlet) 18b and 18d in addition to the two ports (first inlet and first outlet) 18a and 18c. Have. Here, the second inlet 18 b is connected via a pipe 58 to a flow path branch point N ₁ provided on the upstream side of the heating unit 16 of the pipe 16. The second outlet 18 d is connected to a flow path branch point N ₂ provided in the pipe 32 via the pipe 60.

  In the flow path switching unit 18, a plurality of valves, for example, four on-off valves 62, 64, 66, and 68 are provided. Specifically, the first on-off valve 62 is provided between the first inlet 18a and the first outlet 18c, and the second on-off valve 64 is provided between the first inlet 18a and the second outlet 18d. The third on-off valve 66 is provided between the second inlet 18b and the first outlet 18c, and the fourth on-off valve 68 is provided between the second inlet 18b and the second outlet 18d. Is provided. The flow path switching unit 18 can be installed at an arbitrary place, but the opening / closing valve 62 for selectively connecting at least the outlet 22 b of the refrigerant passage 22 and the inlet 24 a of the refrigerant passage 24 is disposed near the mounting table 12. Preferably it is done.

  These on-off valves 62, 64, 66, and 68 may be turned on and off complementarily in a fixed relationship. As an example, the first and third on-off valves 64 and 66 can be configured by normally open valves, and the second and fourth on-off valves 62 and 68 can be configured by normally closed valves. However, from the viewpoint of increasing the types of flow path switching modes, it is preferable that each on-off valve 62, 64, 66, 68 can be turned on and off independently. The operation of each part in the flow path switching unit 18 (on / off operation of the on-off valves 62 to 68) and the flow path switching operation of the entire unit are controlled by the controller 20.

The controller 20 is composed of a computer system including a CPU, a memory, and the like. As described above, the individual operations and overall operations of each part in the substrate temperature control device, particularly the chiller unit 14, the heating unit 16, and the flow path switching unit 18. (Sequence) is controlled. The configuration in the controller 20 (control unit 140) will be described later with reference to FIG.

  Next, the temperature control function in the mounting table temperature control apparatus of this embodiment will be described. In this mounting table temperature control device, the controller 20 controls to combine the on / off state of the heating operation in the heating unit 16 and the on / off state of the on-off valves 62, 64, 66, 68 in the flow path switching unit 18. Six types of modes (A), (B), (C), (D), (E), and (F) are obtained for temperature control on the mounting table 12.

  In mode (A), as shown in FIG. 4, the heating operation is turned on in the heating unit 16, the on-off valves 64 and 66 are turned on in the flow path switching unit 18, and the on-off valves 62 and 68 are turned on, respectively. Turn off. By switching the flow path in the flow path switching unit 18, as shown in FIG. 5, a refrigerant passage 22 in the central region and a refrigerant passage 24 in the peripheral region between the outlet 14a and the return port 14b of the chiller unit 14. Are connected in parallel.

That is, a part of the refrigerant sent from the chiller unit 14 at the base temperature, that is, the refrigerant flowing straight through the pipe branching point N ₁ and flowing through the pipe 26 is desired to have the refrigerant temperature higher than the base temperature by the heating unit 16 on the way. Then, the refrigerant passage 22 is entered. Then, when entering the flow path switching unit 18 from the refrigerant passage 22 through the pipe 28, the refrigerant passes through the on-off valve 64 to the pipe 60 side without going to the refrigerant path 24, and passes through the flow path branch point N _2. Return to the chiller unit 14 through the pipe 32. In addition, the refrigerant branched from the flow path branch point N ₁ to the pipe 58 side enters the refrigerant passage 24 in the peripheral region through the flow path switching unit 18 (the on-off on-off valve 66) and the pipe 30 while maintaining the base temperature. Then, after leaving the refrigerant passage 24, it returns straight to the chiller unit 14 through the pipe 32.

  Thus, according to the mode (A), the temperature of the peripheral region of the mounting table 12 is controlled by the refrigerant having the base temperature, and the central region of the mounting table 12 is set by the refrigerant having the set temperature that is one step higher than the base temperature. The temperature is adjusted. As a result, a mountain-shaped or trapezoidal temperature distribution characteristic is obtained in the mounting table 12 such that the central region is relatively higher than the peripheral region, and the height difference (temperature difference) between the two is arbitrarily controlled. Can do. Moreover, such a temperature distribution characteristic can be established in a short time by the rapid heating function of the heating unit 16 as described above.

  In mode (B), as shown in FIG. 6, the heating operation is turned on in the heating unit 16, the on-off valves 62 and 68 are turned on in the flow path switching unit 18, and the on-off valves 64 and 66 are turned on, respectively. Turn off. By switching the flow path in the flow path switching unit 18, as shown in FIG. 7, a refrigerant passage 22 in the central region and a refrigerant passage in the peripheral region are provided between the outlet 14a and the return port 14b of the chiller unit 14. 24 is connected in series, and a bypass path 70 including a pipe 58, a flow path switching unit 18 and a pipe 60 is also formed.

Specifically, a part of the refrigerant sent out from the chiller unit 14 at the base temperature, that is, the refrigerant flowing straight through the flow path branching point N ₁ and flowing through the pipe 26 is changed to the base temperature by the heating unit 16 on the way. After the temperature is further increased to a desired set temperature, the refrigerant passage 22 is entered. When exiting the refrigerant passage 22, the refrigerant enters the refrigerant passage 24 through the pipe 28, the flow path switching unit 18 (on-off valve 62) and the pipe 30, and after exiting the refrigerant passage 24, passes straight through the pipe 32. Return to the chiller unit 14. On the other hand, the refrigerant branched from the flow path branch point N ₁ to the pipe 58 side passes through the flow path switching unit 18 (on-off valve 68) and the pipe 60 while maintaining the base temperature, and passes from the flow path branch point N ₂ to the pipe 32. , And merges with the refrigerant from the refrigerant passage 24 side and returns to the chiller unit 14.

  Thus, according to this mode (B), the temperature of both the central region and the peripheral region of the mounting table 12 is controlled with the refrigerant having a temperature higher than the base temperature, and the entire mounting table 12 is substantially uniform or flat. It can be controlled to a desired set temperature higher than the base temperature with a simple temperature distribution, and rapid heating by the heating unit 16 is also possible. Here, even if the flow rate of the refrigerant is arbitrarily reduced by the flow rate control valve 44 in the heating unit 16, excess refrigerant flows through the bypass flow path 70, so that the refrigerant circulation capacity (refrigerant delivery pressure) of the chiller unit 14 is kept constant. The desired rapid temperature increase can be immediately and stably performed on the heating unit 16 side.

  The mode (C) takes the same refrigerant supply form as the second mode (B) described above except that the bypass channel 70 is not formed. That is, as shown in FIG. 8, the heating operation is turned on in the heating unit 16, only the on-off valve 62 is turned on in the flow path switching unit 18, and all the other on-off valves 64, 66, 68 are turned off. To. By switching the flow path in the flow path switching unit 18, as shown in FIG. 9, between the outlet 14a and the return port 14b of the chiller unit 14, the refrigerant passage 22 in the central region and the refrigerant passage in the peripheral region. 24 are connected in series, but the flow path is blocked between the pipe 58 and the pipe 60 (by the flow path switching unit 18), so the bypass flow path 70 is not formed.

In this case, all of the refrigerant sent from the chiller unit 14 at the base temperature passes straight through the flow path branch point N ₁ and flows through the pipe 26, and the intermediate heating unit 16 changes the refrigerant temperature from the base temperature to the desired set temperature. After the temperature rises, the refrigerant passage 22 is entered. When exiting the refrigerant passage 22, the refrigerant enters the refrigerant passage 24 through the pipe 28, the flow path switching unit 18 (on-off valve 62) and the pipe 30, and after exiting the refrigerant passage 24, passes straight through the pipe 32. Return to the chiller unit 14.

  In this mode (C), the temperature cannot be increased as quickly and efficiently as the above mode (B), but the entire mounting table 12 is desired to be higher than the base temperature with a substantially flat (uniform) temperature distribution. Can be set to the set temperature.

  In the mode (D), the heating operation of the heating unit 16 is stopped (turned off), and the flow path state in the flow path switching unit 18 is set to the same form as the mode (A) described above. That is, as shown in FIG. 10, the on-off valves 64 and 66 are turned on, and the on-off valves 62 and 68 are turned off. As a result, as shown in FIG. 11, the refrigerant passage 22 in the central region and the refrigerant passage 24 in the peripheral region are connected in parallel between the outlet 14 a and the return port 14 b of the chiller unit 14.

Therefore, a part of the refrigerant sent from the chiller unit 14 at the base temperature, that is, the refrigerant flowing straight through the flow path branch point N ₁ and flowing through the pipe 26 is not heated by the heating unit 16 in the middle. The refrigerant enters the refrigerant passage 22 as it is. Then, when the refrigerant exits from the refrigerant passage 22 and enters the flow path switching unit 18 through the pipe 28, the refrigerant passes through the on-off valve 64 to the pipe 60 side without going to the refrigerant passage 24, and passes through the flow path branch point N _2. Return to the chiller unit 14 through the pipe 32. In addition, the refrigerant that has been diverted from the flow path branching point N ₁ to the pipe 58 side also enters the refrigerant passage 24 in the peripheral region through the flow path switching unit 18 (on-off valve 66) and the pipe 30 while maintaining the base temperature. Then, after leaving the refrigerant passage 24, it returns straight to the chiller unit 14 through the pipe 32.

  Thus, according to the mode (D), both the central region and the peripheral region of the mounting table 12 are temperature-controlled with the base temperature refrigerant, and the entire mounting table 12 has a substantially flat (uniform) temperature distribution. Thus, the temperature can be controlled near the base temperature. What is important here is that the transition from the mode (A) to the mode (D) only needs to be performed by switching the heating unit 16 from the on state to the off state, and can be performed at high speed. That is, the rapid temperature decrease from the set temperature to the base temperature can be realized by stopping the rapid temperature increase by the heating unit 16. Transition from the mode (B) or the mode (C) to the mode (D) can be similarly performed at high speed only by increasing the switching operation of the flow path switching unit 18.

  In the mode (E), the heating operation of the heating unit 16 is stopped (turned off), and the flow path state in the flow path switching unit 18 is changed to the same mode as the mode (B) described above. That is, as shown in FIG. 12, the on-off valves 62 and 68 are turned on, and the on-off valves 64 and 66 are turned off. Accordingly, as shown in FIG. 13, the refrigerant passage 22 in the central region and the refrigerant passage 24 in the peripheral region are connected in series between the outlet 14a and the return port 14b of the chiller unit 14, and the piping 58, a bypass path 70 including a flow path switching unit 18 and a pipe 60 is also formed.

In this case, a part of the refrigerant sent from the chiller unit 14 at the base temperature, that is, the refrigerant flowing straight through the flow path branch point N ₁ and flowing through the pipe 26 is not heated by the heating unit 16 in the middle. The refrigerant enters the refrigerant passage 22 while maintaining the temperature. When exiting the refrigerant passage 22, the refrigerant enters the refrigerant passage 24 through the pipe 28, the flow path switching unit 18 (on-off valve 62) and the pipe 30, and after exiting the refrigerant passage 24, passes straight through the pipe 32. Return to the chiller unit 14. On the other hand, the refrigerant branched to the pipe 28 side from the flow path branch point N ₁ passes through the flow path switching unit 18 (on-off valve 68) and the pipe 60 while maintaining the base temperature, and passes from the flow path branch point N ₂ to the pipe 32. , And merges with the refrigerant from the refrigerant passage 24 side and returns to the chiller unit 14.

  Also in this mode (E), the temperature of both the central region and the peripheral region of the mounting table 12 is controlled with the base temperature refrigerant, and the entire mounting table 12 is controlled to a temperature near the base temperature with a substantially flat temperature distribution. can do. In addition, the mode (A), mode (B), or mode (C) to mode (E) can be changed easily and at high speed.

Strictly speaking, the temperature distribution of the mounting table 12 is slightly different between the mode (E) and the mode (D). That is, in the mode (D), the refrigerant sent from the chiller unit 14 at the base temperature is divided into two at the flow path branch point N ₁ of the pipe 26, and the refrigerant passage 22 and the peripheral area in the central area of the mounting table 12. Therefore, the central region and the peripheral region of the mounting table 12 are temperature-controlled at substantially the same refrigerant temperature, and the flatness of the temperature distribution in the entire mounting table 12 ( Uniformity) is high. On the other hand, in the mode (E), all of the refrigerant delivered from the chiller unit 14 at the base temperature first flows through the refrigerant passage 22 in the central region of the mounting table 12 and then further in the peripheral region of the mounting table 12. Therefore, the cooling capacity is slightly weaker in the latter (peripheral region) than in the former (central region), and the temperature distribution in the entire mounting table 12 is not strictly flat, and the central portion is closer to the peripheral portion. Tend to be a little higher.

  Finally, in the sixth mode (F), the heating operation of the heating unit 16 is stopped (turned off), and the flow path state in the flow path switching unit 18 is changed to the same mode as the above mode (C). To do. That is, as shown in FIG. 14, only the on-off valve 62 is turned on, and the other on-off valves 64, 66, 68 are all turned off. As shown in FIG. 15, the refrigerant passage 22 in the central region and the refrigerant passage 24 in the peripheral region are connected in series between the outlet 14 a and the return port 14 b of the chiller unit 14. Since the flow path is shut off from the pipe 60 (by the flow path switching unit 18), the bypass flow path 70 is not formed.

In this case, all of the refrigerant sent from the chiller unit 14 at the base temperature passes straight through the flow path branch point N ₁ and flows through the pipe 26, and remains at the base temperature without being heated by the heating unit 16 in the middle. Enter passage 22. When exiting the refrigerant passage 22, the refrigerant enters the refrigerant passage 24 through the pipe 28, the flow path switching unit 18 (on-off valve 62) and the pipe 30, and after exiting the refrigerant passage 24, passes straight through the pipe 32. Return to the chiller unit 14.

  Also in this mode (F), both the central region and the peripheral region of the mounting table 12 are temperature-controlled with the base temperature refrigerant, and the entire mounting table 12 is controlled to a temperature near the base temperature with a substantially flat temperature distribution. can do. In addition, the mode (A), mode (B), or mode (C) to mode (F) can be easily and quickly transferred.

  Strictly speaking, mode (F) also has operational differences from mode (D) and mode (E). The difference from mode (D) is the same as described above for mode (E). Further, in comparison with mode (E), in mode (F), the bypass flow path 70 is not formed, so that all of the refrigerant sent from the chiller unit 14 can flow to the refrigerant passages 22 and 24 of the mounting table 12. Further, the temperature control function by the chiller unit 14 can be more fully exhibited.

  As described above, in this embodiment, one chiller unit 14, the heating unit 16 using the in-line heater 40, the flow path switching unit 18 composed of four on-off valves 62, 64, 66, and 68, The temperature or temperature distribution of the mounting table 12 can be converted into various kinds of set values or profiles by a mounting table temperature control device having a low-cost and simple configuration having a controller 20 that controls the operation or state of each unit 14, 16, 18. It can be controlled with high accuracy at high speed.

  FIG. 16 shows a configuration of a plasma processing apparatus in one embodiment of the present invention. The plasma processing apparatus incorporates the mounting table temperature control apparatus according to the first embodiment.

As shown in FIG. 16, this plasma processing apparatus is configured as a parallel plate type plasma etching apparatus, and has an alumina film, an yttrium oxide (Y ₂ O ₃ ) film, a ceramic coating whose inner wall surface is anodized. Alternatively, a cylindrical chamber (processing vessel) 90 made of aluminum or stainless steel covered with quartz is provided. This chamber 90 corresponds to the chamber 10 of FIG. The chamber 90 is grounded for safety.

  In the chamber 90, for example, a disk-shaped mounting table 12 on which a semiconductor wafer W is mounted as a substrate to be processed is provided as a lower electrode or a susceptor. The mounting table 12 is made of aluminum, for example, and is supported by a cylindrical support portion 94 that extends in the vertical direction from the bottom of the chamber 90 via an insulating cylindrical holding portion 92. On the upper surface of the cylindrical holding portion 92, a focus ring 96 made of quartz, for example, surrounding the upper surface of the mounting table 12 in an annular shape is disposed.

  An exhaust path 98 is formed between the side wall of the chamber 90 and the cylindrical support portion 94, and an annular baffle plate 100 is attached to the exhaust path 98 or in the middle of the exhaust path 98, and an exhaust port 102 is provided at the bottom. . An exhaust device 106 is connected to the exhaust port 102 via an exhaust pipe 104. The exhaust device 106 includes a vacuum pump, and can reduce the processing space in the chamber 90 to a predetermined degree of vacuum. A gate valve 108 that opens and closes the loading / unloading port of the semiconductor wafer W is attached to the side wall of the chamber 90.

  A high-frequency power source 110 for generating plasma is electrically connected to the mounting table 12 via a matching unit 112 and a power feed rod 114. The high frequency power supply 110 applies a desired high frequency, for example, a high frequency of 27 MHz or more (for example, 60 MHz) to the lower electrode, that is, the mounting table 12. Facing the mounting table 12 in parallel, a shower head 116 is provided on the ceiling of the chamber 90 as an upper electrode of the ground potential. A high frequency electric field is formed in the space between the mounting table 12 and the shower head 116, that is, the plasma generation space PS by the high frequency from the high frequency power supply 110.

  The shower head 116 includes an electrode plate 118 having a large number of gas vent holes 118a, and an electrode support 120 that detachably supports the electrode plate 118. A buffer chamber 122 is provided inside the electrode support 120, and a gas supply pipe 126 from the processing gas supply unit 124 is connected to the gas inlet 122 a of the buffer chamber 122.

  In the ceiling portion of the chamber 90, a magnetic field forming mechanism 128 extending annularly or concentrically is provided above the periphery of the plasma generation space PS (preferably around the shower head 116). The magnetic field forming mechanism 128 functions to facilitate the start of high-frequency discharge (plasma ignition) in the plasma generation space PS in the chamber 90 and maintain the discharge stably.

  An electrostatic chuck 130 for holding the semiconductor wafer W with an electrostatic attraction force is provided on the upper surface of the mounting table 12. The electrostatic chuck 130 has an electrode 130a made of a conductive film sandwiched between a pair of insulating films 130b and 130c, and a DC power source 132 is electrically connected to the electrode 130a via a switch 134. The semiconductor wafer W can be attracted and held on the chuck by a Coulomb force by a DC voltage from the DC power source 132.

  Similar to the first embodiment described above, the mounting table 12 is provided with a first refrigerant passage 22 extending annularly or spirally in the central region, and annularly or spirally in the peripheral region. An extended second refrigerant passage 24 is provided. A refrigerant having a predetermined temperature is circulated and supplied to the refrigerant passages 22 and 24 from a mounting table temperature control apparatus similar to that of the first embodiment having the chiller unit 12, the heating unit 16, and the flow path switching unit 18. The

  Further, a heat transfer gas such as He gas from the heat transfer gas supply unit 136 is supplied between the upper surface of the electrostatic chuck 130 and the back surface of the semiconductor wafer W via the gas supply line 138.

  The control unit 140 individually controls each part in the plasma etching apparatus and controls the entire sequence as a whole, and also serves as the controller 20 (FIG. 1) of the mounting table temperature control apparatus.

  In this plasma processing apparatus, although not shown in the figure, a high frequency power source having a frequency of 27 MHz or more, for example, 60 MHz, is connected to the shower head 116 as an upper electrode, and a frequency within a range of 2 MHz to 27 MHz, for example, to the mounting table 12 as a lower electrode. You may make it the structure which connects a 2 MHz high frequency power supply. In this case, a high pass filter (HPF) for passing a high frequency (60 MHz) from the shower head 116 side to the ground is electrically connected to the mounting table 12, and a high frequency (2 MHz from the mounting table 12 side is connected to the shower head 116. ) Is preferably electrically connected to a low pass filter (LPF) for passing through the ground.

  In order to perform etching in this plasma processing apparatus, first, the gate valve 108 is opened, and the semiconductor wafer W to be processed is loaded into the chamber 90 and mounted on the mounting table 12. Next, a DC voltage is applied from the DC power source 134 to the electrode 130 a of the electrostatic chuck 130 to fix the semiconductor wafer W on the electrostatic chuck 130. Then, the temperature of the mounting table 12 is controlled as will be described later, and the heat transfer gas from the heat transfer gas supply unit 136 is supplied to the upper surface of the electrostatic chuck 130 and the back surface of the semiconductor wafer W. Thereafter, an etching gas (generally a mixed gas) is introduced into the chamber 90 from the processing gas supply unit 124 at a predetermined flow rate and flow rate ratio, the pressure in the chamber 90 is set to a set value by the exhaust device 106, and the high-frequency power source 110. A high frequency is supplied to the mounting table 12 with a predetermined power. The etching gas discharged from the shower head 116 is discharged into plasma in the plasma generation space PS, and the main surface of the semiconductor wafer W is etched by radicals and ions generated by the plasma.

  In the plasma etching as described above, some examples of methods for controlling etching characteristics using the mounting table temperature control technique in this embodiment will be described.

  In the plasma processing apparatus, the temperature distribution of the substrate to be processed is affected variously on the mounting table by the type of process and the apparatus structure. Generally, the temperature on the substrate tends to be higher at the edge portion than at the central portion due to plasma, thermal radiation from the chamber wall, high density electrons, or the like. As described above, according to the present invention, the temperature of the surface of the semiconductor wafer W can be made uniform by applying the temperature control mode (A).

  That is, as described above, by selecting the mode (A) (FIGS. 4 and 5) in the temperature control of the mounting table 12, the temperature on the inner side (center region) of the mounting table 12 is increased. be able to. Accordingly, as shown in FIG. 17, in the semiconductor wafer W on the mounting table 12, a substantially uniform (flat) temperature distribution can be obtained in the central region and the peripheral region. Incidentally, when a refrigerant having a temperature substantially equal to the fluid passages 22 and 24 of the mounting table 12 is flowed, the central region and the peripheral region of the mounting table 12 have a substantially uniform (flat) temperature distribution as shown in FIG. As a result, in the semiconductor wafer W on the mounting table 12, the peripheral region tends to be higher than the central region due to plasma, thermal radiation from the chamber wall, or the like.

  Next, a second example will be described with reference to FIG. In this example, a multilayer film formed on the main surface of the semiconductor wafer W, for example, a conductive layer having a two-layer structure is processed to form a fine width wiring. In this case, a sequence for switching the temperature control mode from mode (B) (FIGS. 6 and 7) to mode (D) (FIGS. 10 and 11) is effective.

  In this conductive layer etching, a mixed gas containing, for example, a chlorine-based halide is used as an etching gas. In the temperature control of the mounting table 12, as shown in FIG. 19, first, the entire semiconductor wafer W is made to have a substantially uniform temperature distribution at a desired set temperature by the mode (B). In that case, the semiconductor wafer W can be raised to the first set temperature (for example, 60 ° C.) at a high response speed by the high-speed temperature raising function. In this state, an etching gas is introduced into the chamber 90 and plasma excitation is performed by high frequency to process the upper conductive layer.

  Subsequently, the introduction of the etching gas is temporarily stopped, and this time the temperature control of the mounting table 12 is switched from the mode (B) to the mode (D). Also in this case, the temperature of the entire mounting table 12 can be lowered at a high speed to a second set temperature (for example, 30 ° C.) corresponding to the base temperature by the high speed temperature decreasing function.

  In this way, as shown in FIG. 19, the temperature of the entire semiconductor wafer W is also lowered at a high speed by switching from the mode (B) to the mode (D). In this state, an etching gas is again introduced into the chamber 90 and plasma excitation is performed to process the lower conductive layer. In this way, a laminated wiring whose dimensions are controlled with high accuracy can be formed.

  In addition, various temperature control sequences are possible in the plasma processing. FIG. 20 shows a sequence reverse to that in FIG. 19. First, the first layer of the multilayer film is processed under mode (D), and then the lower layer film is processed under mode (B). Also in this case, the temperature of the mounting table 12 can be switched at high speed from the set temperature (for example, 30 ° C.) in the mode (D) to the set temperature (for example, 60 ° C.) in the mode (B).

FIG. 21 shows a third example. In the plasma processing apparatus, as described above, the substrate to be processed on the mounting table receives plasma, thermal radiation from the chamber wall, or high-density electron incidence during the plasma processing. This means that when the plasma processing is started, that is, when high-frequency (RF) power supply is started with respect to the high-frequency electrode, the substrate temperature fluctuates in the direction of increasing as shown by a one-dot chain line 144 in FIG. . However, in order to act also temperature control by mounting table, the temperature rise of the substrate if the time π is the lapse of a certain time constant (variation) reaches the equilibrium temperature T _W is saturated. However, in this case, the temperature of the substrate cannot be maintained at the set processing temperature (recipe temperature condition) throughout the plasma processing period, and the reliability is low in terms of reproducibility and yield of the plasma processing.

In this regard, according to the present invention, a desired plasma process is started after the semiconductor wafer W carried into the chamber 10 is placed on the mounting table 12 by using the rapid temperature raising / lowering function of the heating unit 16. 21, the refrigerant flowing through the pipe 26 is heated by the rapid temperature raising function of the heating unit 16 as indicated by solid lines 148a and 146 in FIG. 21 to set the temperature of each semiconductor wafer Wn to the set processing temperature (T _W ) for processing. Get up quickly. Then, the heating unit 16 heats the refrigerant flowing through the pipe 26 so that the temperature of the semiconductor wafer Wn is substantially maintained at the set processing temperature (T _W ) until the processing is completed after the plasma processing is started. Is gradually weakened as shown by the solid line 148b in FIG. In this way, it is possible to correct wafer temperature fluctuation (rise) due to heat input from plasma or the like, and to improve the temperature management, reproducibility, and yield of the single wafer plasma processing.

  In the above-described embodiment, the base temperature of the refrigerant in the chiller unit 14 is kept constant in the sequence for switching the temperature control mode. However, the present invention is not limited to an aspect in which the base temperature is kept constant. It is also possible to arbitrarily change the base temperature with the heater 38 of the chiller unit 14, and by using the variable control of the base temperature in combination with the temperature raising / lowering function of the heating unit 16, more various temperature controls can be realized. .

  As an example, FIG. 22 shows an example in which the temperature of the semiconductor wafer W is lowered in three stages. As described above, since the chiller unit 14 has a large heat capacity and is disposed at a position that is considerably away from the mounting table 12, it is considerably long after the base temperature is changed by the chiller unit 14 until the temperature of the mounting table 12 follows. It takes time (response speed is slow).

  Therefore, as shown in FIG. 22, in the first stage, the base temperature is set to a relatively high temperature, the heating unit 16 is turned on, and the temperature of the refrigerant is maintained at a constant temperature higher than the base temperature. Thus, the temperature of the semiconductor wafer W is maintained at the first set temperature. Next, in the second stage, the chiller unit 14 switches the base temperature to a lower reference temperature. However, since the time constant for switching the base temperature is large, the temperature of the refrigerant supplied to the mounting table 12 gradually decreases, and the temperature of the semiconductor wafer W also gradually decreases accordingly. I can't. Therefore, in the second stage, the heating operation of the heating unit 16 is temporarily stopped, and the temperature of the semiconductor wafer W is rapidly lowered to a second set temperature lower than the first set temperature by rapid temperature drop. Then, the heating operation of the heating unit 16 is restarted, and the heating temperature is gradually increased through the temperature controller 54 in accordance with the time constant of the base temperature. Thus, the semiconductor wafer W is held at the second set temperature during the second stage. Next, when the base temperature is stabilized at the new reference value, the heating operation of the heating unit 16 is stopped. By this rapid temperature decrease, the temperature of the semiconductor wafer W can be lowered at a stretch from the second set temperature to the third set temperature corresponding to the new base temperature.

  As described above, the temperature of the semiconductor wafer W is maintained at, for example, 90 ° C. in the first stage, 60 ° C. in the second stage, and 30 ° C. in the third stage. Processing can be performed with high accuracy. Alternatively, the single layer film can be processed into a desired cross-sectional shape.

  FIG. 23 shows a temperature control sequence opposite to that shown in FIG. 22, and shows an example in which the temperature of the semiconductor wafer W is raised in three stages. According to this sequence, the temperature of the semiconductor wafer W can be maintained, for example, at 30 ° C. in the first stage, 60 ° C. in the second stage, and 90 ° C. in the third stage. Similarly, the multilayer film can be etched with high accuracy.

  FIG. 24 shows a configuration example of the control unit 140 (controller 20). The controller 140 (controller 20) of this configuration example includes a processor (CPU) 152, a memory (RAM) 154, a program storage device (HDD) 156, a disk drive such as a floppy drive or an optical disk connected via a bus 150 ( DRV) 158, an input device (KEY) 160 such as a keyboard and a mouse, a display device (DIS) 162, a network interface (COM) 164, and a peripheral interface (I / F) 166.

  The processor (CPU) 152 reads a code of a required program from a storage medium 168 such as an FD or an optical disk loaded in the disk drive (DRV) 158 and stores it in the HDD 156. Alternatively, a required program can be downloaded from the network via the network interface 164. Then, the processor (CPU) 152 develops the code of the program necessary for each stage or each scene from the HDD 156 onto the working memory (RAM) 154, executes each step, performs necessary arithmetic processing, and performs the peripheral interface 166. Each part (especially chiller unit 14, heating unit 16, flow path switching unit 18 etc.) in the apparatus is controlled via All programs for executing the mounting table temperature control method described in the first and second embodiments are executed by this computer system.

  Although the preferred embodiments of the present invention have been described above, the above-described embodiments do not limit the present invention. Those skilled in the art can make various modifications and changes in specific embodiments without departing from the technical idea and technical scope of the present invention.

  For example, in the flow path switching unit 18, a pair of solenoid valves 62 and 64 are connected to a first port connected to the first inlet 18a and first and second outlets 18c and 18d, respectively. A single directional valve with two and third ports can be substituted. The set of solenoid valves 66 and 68 includes a first port connected to the second inlet 18a, and second and third ports connected to the first and second outlets 18c and 18d, respectively. It can also be replaced with one directional control valve having However, in that case, there is a restriction that the modes (C) and (F) cannot be obtained.

  In the above embodiment, a cooling unit that cools the refrigerant in the middle of the pipe 26 can be used instead of the heating unit 16. In that case, for example, a profile in which the profile of FIG. 17 is inverted up and down can be obtained for the temperature distribution of the semiconductor wafer W on the mounting table 12 by the mode (A). Alternatively, it is also possible to use a system in which the refrigerant sent from the chiller unit 14 at the base temperature is first flowed to the refrigerant passage 24 in the peripheral region of the mounting table 12 and then serially flows to the central region 22. Furthermore, a configuration in which three or more refrigerant passages having individual inlets and outlets are provided on the mounting table 12 is also possible.

  In addition to the parallel plate type plasma processing apparatus as in the above embodiment, the present invention includes a helicon wave plasma excitation type processing apparatus, an ECR (Electron Cyclotron Resonance) plasma excitation type processing apparatus, a μ wave plasma excitation type processing apparatus. The present invention can be similarly applied to a processing apparatus, an ICP (Inductively Coupled Plasma) plasma excitation type processing apparatus, and the like. In addition to the etching apparatus, the present invention can be similarly applied to a film forming apparatus, for example, a chemical vapor deposition (CVD) apparatus, a plasma CVD apparatus, a sputtering apparatus, an MBE apparatus, and a vapor deposition apparatus. Furthermore, the present invention can be similarly applied to ion milling, processing of an object to be processed by FIB, plasma cleaning of an insulating substrate surface, plasma cleaning, and the like.

  In addition, the substrate to be processed in the present invention is not limited to a semiconductor wafer, and may be various substrates for flat panel displays, photomasks, CD substrates, and the like.

It is a block diagram which shows the structure of the mounting base temperature control apparatus in one Embodiment of this invention. It is a perspective view which shows an example of the in-line heater in the heating unit of the said mounting base temperature control apparatus. It is a graph which shows the refrigerant temperature raising / lowering characteristic in the said heating unit. It is a figure which shows the state of each part for obtaining temperature control mode (A) in the mounting base temperature control apparatus. It is a figure which shows typically the whole flow-path type | system | group in temperature control mode (A). It is a figure which shows the state of each part for obtaining the temperature control mode (B) in the above-mentioned pedestal temperature control apparatus. It is a figure which shows typically the whole flow-path type | system | group in temperature control mode (B). It is a figure which shows the state of each part for obtaining temperature control mode (C) in the said mounting base temperature control apparatus. It is a figure which shows typically the whole flow-path type | system | group in temperature control mode (C). It is a figure which shows the state of each part for obtaining temperature control mode (D) in the said mounting base temperature control apparatus. It is a figure which shows typically the whole flow-path type | system | group in temperature control mode (D). It is a figure which shows the state of each part for obtaining temperature control mode (E) in the above-mentioned pedestal temperature control apparatus. It is a figure which shows typically the whole flow-path type | system | group in temperature control mode (E). It is a figure which shows the state of each part for obtaining temperature control mode (F) in the above-mentioned pedestal temperature control apparatus. It is a figure which shows typically the whole flow-path type | system | group in temperature control mode (F). It is sectional drawing which shows the structure of the plasma etching apparatus in one Embodiment of this invention. It is a figure which shows the temperature distribution of the mounting base and semiconductor wafer in one Example. It is a figure which shows the temperature distribution of the mounting base in a reference example, and a semiconductor wafer. It is a figure which shows the sequence of the temperature control mode switching in one Example. It is a figure which shows the sequence of the temperature control mode switching in one Example. It is a figure which shows the to-be-processed object temperature control method in one Example. It is a figure which shows the sequence of the temperature control mode switching in one Example. It is a figure which shows the sequence of the temperature control mode switching in one Example. It is a block diagram which shows the structure of the control part (controller) in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Chamber 12 Mounting stand 14 Chiller unit 16 Heating unit 18 Flow path switching unit 20 Controller 22 Refrigerant passage of central region of mounting base 24 Refrigerant passage of peripheral portion region of mounting base Temperature controller 26, 28, 30, 32, 58 , 60 Piping 34 Pump 36 Refrigerator 38 Heater 40 Inline heater 42 Power supply 44 Flow rate control valve 54 Temperature controller 62, 64, 66, 68 Open / close valve 90 Chamber 110 High frequency power supply 124 Processing gas supply unit 130 Electrostatic chuck 136 Heat transfer Gas supply unit 140 Control unit

Claims (22)

A mounting table temperature control device for controlling the temperature of a mounting table for mounting the object to be processed in a chamber of a processing apparatus that performs a desired process on the object to be processed under reduced pressure ,
First and second refrigerant passages each having a separate inlet and outlet provided in the mounting table;
In order to circulate and supply the refrigerant to the first and second refrigerant passages, the outlet connected to the inlet of the first refrigerant passage via the first passage, and the second refrigerant passage A refrigerant circulator having a return port connected to the outlet of the refrigerant through a second flow path, returning the refrigerant returned to the return port to a reference temperature and sending the refrigerant from the outlet.
A refrigerant temperature controller that raises or lowers the temperature of the refrigerant from the reference temperature to a desired set temperature in the middle of the first flow path;
A first port connected to an outlet of the first refrigerant passage via a third flow path, and a first flow provided upstream of the refrigerant temperature control unit of the first flow path. A second port connected to a road branch point via a fourth flow path, a third port connected to an inlet of the second refrigerant path via a fifth flow path, and the second port A fourth port connected to a second flow path branch point provided in the flow path via a sixth flow path, and the first, second, third and fourth ports, A flow path switching unit capable of conducting, blocking and changing the flow path between,
A mounting table temperature control device comprising: a channel control unit that controls conduction, blocking, or change of the channel in the channel switching unit. The flow path switching unit is connected between the first on-off valve connected between the first port and the third port, and between the first port and the fourth port. A second on-off valve, a third on-off valve connected between the second port and the third port, and a connection between the second port and the fourth port; A fourth on-off valve;
The flow path control unit controls on / off of the first, second, third and fourth on-off valves ;
The mounting table temperature control apparatus according to claim 1. The flow path switching unit includes a first direction switching valve connected between the first port and the third and fourth ports, the second port, and the third and fourth ports. A second directional control valve connected between
The flow path control unit controls respective flow path states in the first and second directional control valves ;
The mounting table temperature control apparatus according to claim 1. The refrigerant temperature control unit,
An in-line heater attached to the first flow path;
A temperature sensor for detecting the temperature of the refrigerant in the first flow path downstream of the in-line heater;
And a temperature control unit for controlling the heating value of the in-line heater to match the refrigerant temperature detected in the setting temperature by the temperature sensor, the mounting table temperature according to any one of claims 1 to 3 Control device. The in-line heater to heat the refrigerant in the first flow path at a position close to the mounting table, the mounting table temperature control device according to claim 4. 6. The mounting according to claim 1 , wherein a flow rate control valve for variably controlling the flow rate of the refrigerant is provided downstream of the first flow channel from the first flow channel branch point. Station temperature control device. Wherein the first refrigerant passage second coolant passage is arranged concentrically with respect to the center of the mounting table, the mounting table temperature control device according to any one of claims 1 to 6. The first refrigerant passage is provided in the central region of the mounting table, wherein the second refrigerant passage provided in the peripheral region of the mounting table, the mounting according to any one of claims 1 to 7 Station temperature control device. The refrigerant circulator has a pump for circulating a refrigerant, and a refrigeration unit for freezing the refrigerant immediately after feedback, and a heating unit for heating the refrigerant after the refrigeration to a predetermined reference temperature, claim 1 The mounting table temperature control device according to claim 8. Refrigerant is circulated and supplied from a refrigerant circulator to first and second refrigerant passages provided on a mounting table for mounting the object to be processed in a chamber of a processing apparatus that performs a desired process on the object to be processed under reduced pressure. A mounting table temperature control method for controlling the temperature of the mounting table described above,
A part of the refrigerant sent from the refrigerant circulator at a reference temperature by connecting the first refrigerant passage and the second refrigerant passage in parallel between the outlet and the return outlet of the refrigerant circulator. The temperature is raised or lowered from the reference temperature to a desired set temperature and then flowed to the first refrigerant passage, and the rest is caused to flow to the second refrigerant passage substantially at the reference temperature to control the temperature of the mounting table. a first temperature control mode of performing,
The first refrigerant passage and the second refrigerant passage are connected in parallel between the outlet and the return port of the refrigerant circulator, and a part of the refrigerant sent from the refrigerant circulator is substantially And the second temperature control mode for controlling the temperature of the mounting table by flowing the remaining temperature in the first refrigerant passage at the reference temperature and flowing the remaining flow in the second refrigerant passage at the reference temperature substantially. Have
Switching between the first temperature control mode and the second temperature control mode according to the processing conditions of the object to be processed ,
Mounting table temperature control method. The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and a part of the refrigerant sent from the refrigerant circulator is used as the reference. A third temperature control mode for controlling the temperature of the mounting table by further flowing the first and second refrigerant passages sequentially after raising or lowering the temperature to a desired set temperature and bypassing the rest;
Switching between the first temperature control mode, the second temperature control mode, and the third temperature control mode according to the processing conditions of the object to be processed .
The mounting table temperature control method according to claim 10 . The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and all of the refrigerant sent from the refrigerant circulator is reduced from the reference temperature. A fourth temperature control mode for controlling the temperature of the mounting table by sequentially flowing through the first and second fluid passages after raising or lowering the temperature to a desired set temperature;
Switching between the first temperature control mode, the second temperature control mode, and the fourth temperature control mode according to the processing conditions of the object to be processed .
The mounting table temperature control method according to claim 10 . The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and a part of the refrigerant sent from the refrigerant circulator is substantially A fifth temperature control mode for sequentially flowing the first and second refrigerant passages at the reference temperature and bypassing the rest to control the temperature of the mounting table,
Switching between the first temperature control mode , the second temperature control mode, and the fifth temperature control mode according to the processing conditions of the object to be processed .
The mounting table temperature control method according to claim 10 . The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and substantially all of the refrigerant sent from the refrigerant circulator is substantially A sixth temperature control mode for sequentially controlling the temperature of the mounting table by sequentially flowing the first and second refrigerant passages at a reference temperature;
Switching between the first temperature control mode, the second temperature control mode, and the sixth temperature control mode according to the processing conditions of the object to be processed .
The mounting table temperature control method according to claim 10 . Refrigerant is circulated and supplied from a refrigerant circulator to first and second refrigerant passages provided on a mounting table for mounting the object to be processed in a chamber of a processing apparatus that performs a desired process on the object to be processed under reduced pressure. A mounting table temperature control method for controlling the temperature of the mounting table described above,
A part of the refrigerant sent from the refrigerant circulator at a reference temperature by connecting the first refrigerant passage and the second refrigerant passage in parallel between the outlet and the return outlet of the refrigerant circulator. The temperature is raised or lowered from the reference temperature to a desired set temperature and then flowed to the first refrigerant passage, and the rest is caused to flow to the second refrigerant passage substantially at the reference temperature to control the temperature of the mounting table. A first temperature control mode for performing
The first refrigerant passage and the second refrigerant passage are connected in parallel between the outlet and the return port of the refrigerant circulator, and a part of the refrigerant sent from the refrigerant circulator is substantially A second temperature control mode for controlling the temperature of the mounting table by flowing the remaining temperature in the first refrigerant passage at the reference temperature and flowing the remainder in the second refrigerant passage at the reference temperature substantially;
The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and a part of the refrigerant sent from the refrigerant circulator is used as the reference. A third temperature control mode for controlling the temperature of the mounting table described above by sequentially flowing the first and second refrigerant passages after raising or lowering the temperature to a desired set temperature and bypassing the rest;
The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and all of the refrigerant sent from the refrigerant circulator is reduced from the reference temperature. A fourth temperature control mode for controlling the temperature of the mounting table by sequentially flowing through the first and second fluid passages after raising or lowering to a desired set temperature;
The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and a part of the refrigerant sent from the refrigerant circulator is substantially A fifth temperature control mode for controlling the temperature of the mounting table by sequentially flowing the first and second refrigerant passages at the reference temperature and bypassing the rest ,
The first refrigerant passage and the second refrigerant passage are connected in series between the outlet and the return port of the refrigerant circulator, and substantially all of the refrigerant sent from the refrigerant circulator is substantially Among the sixth temperature control modes for controlling the temperature of the mounting table by sequentially flowing the first and second refrigerant passages while maintaining the reference temperature,
Switching between either the first mode or the second mode and any of the third mode, the fourth mode, the fifth mode, or the sixth mode ; Mounting table temperature control method. A chamber capable of depressurization for accommodating a mounting table for mounting the object to be processed;
The mounting table temperature control device according to any one of claims 1 to 9 for controlling the temperature of the mounting table,
An exhaust section for exhausting the chamber;
A processing gas supply unit configured to supply a processing gas into the chamber. Having a plasma source for generating or supplying a plasma of the process gas into said chamber, the processing apparatus according to claim 16. The processing apparatus of Claim 17 which has a 1st high frequency electric power feeding part for electrically feeding a 1st high frequency to the mounting table. A counter electrode facing the mounting table in said chamber, said counter electrode having a second high-frequency power supply portion for supplying the second high-frequency, processing apparatus according to claim 17 or claim 18. The mounting table includes an electrostatic chuck for electrostatically adsorbing the object to be processed, and a heat transfer gas supply path for supplying a heat transfer gas between a back surface and a mounting surface of the object to be processed . processing apparatus according to any one of claims 16-19. Before a desired plasma process is started on the object to be processed, the refrigerant flowing through the first flow path is heated by the refrigerant temperature control unit to bring the temperature of the object to be processed to a set processing temperature for processing. Launch,
The coolant temperature control section causes the first flow path to flow so that the temperature of the object to be processed is substantially maintained at the set processing temperature from the start of the plasma processing to the end of the processing thereafter. Gradually reduce heating to the refrigerant ,
Processing apparatus according to any one of claims 17-20. A control program that operates on a computer and causes the computer to control the mounting table temperature control device so that the mounting table temperature control method according to any one of claims 10 to 15 is performed at the time of execution. .

Images