Pad temperature adjusting device, pad temperature adjusting method, and polishing device

Abstract

Provided is a pad temperature adjusting device capable of improving the control responsiveness of the surface temperature of a polishing pad and capable of adjusting the surface temperature of the polishing pad without generating defects such as scratches and contamination on a substrate. The pad temperature adjusting device (5) includes a heat exchanger (11) disposed above a polishing pad (3) and maintained at a prescribed temperature; a pad temperature measurer (39) that measures the surface temperature of the polishing pad (3); a distance sensor (14) that measures the distance between the polishing pad (3) and the heat exchanger (11); a vertical movement mechanism (71) that vertically moves the heat exchanger (11) relative to the polishing pad (3); and a control device (40) that controls the operation of the vertical movement mechanism (71) based on the measurement value of the pad temperature measurer (39).

Description

TECHNICAL FIELD

[0001] The present application relates to a pad temperature adjusting device and a pad temperature adjusting method that adjust the surface temperature of a polishing pad used for polishing a substrate such as a wafer. In addition, the present application relates to a polishing device that incorporates the pad temperature adjusting device. BACKGROUND

[0002] A polishing device is known that holds a substrate such as a wafer on a polishing head and rotates the substrate, further pressing the substrate against a polishing pad on a rotating polishing table, thereby polishing the surface of the substrate. During polishing of the substrate, a polishing liquid (e.g., slurry) is supplied to the polishing pad, and the surface of the substrate is planarized by the chemical action of the polishing liquid and the mechanical action of abrasive grains contained in the polishing liquid.

[0003] The polishing rate of the substrate depends not only on the polishing load of the substrate against the polishing pad, but also on the surface temperature of the polishing pad. This is because the chemical action of the polishing liquid on the substrate depends on the temperature. Therefore, in the manufacture of semiconductor devices, in order to increase the polishing rate of the substrate and further maintain it constant, it is important to maintain the surface temperature of the polishing pad during polishing of the substrate at an optimum value.

[0004] In response to this, a pad temperature adjusting device that adjusts the surface temperature of the polishing pad has been used in the past (see, for example, Patent Literature 1, Patent Literature 2). Generally, the pad temperature adjusting device is provided with a heat exchanger that can be brought into contact with the surface (polishing surface) of the polishing pad, a liquid supply system that supplies a heating liquid and a cooling liquid that are temperature-adjusted to the heat exchanger, a pad temperature measurer that measures the surface temperature of the polishing pad, and a control device that controls the liquid supply system based on the measurement value of the pad temperature measurer. The control device brings the surface temperature of the polishing pad to a prescribed target temperature, and then controls the flow rates of the heating liquid and the cooling liquid based on the pad surface temperature measured by the pad temperature measurer to maintain it at the target temperature.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2017-148933

[0008] Patent Literature 2: Japanese Patent Application Publication No. 2018-027582

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] However, since the heat exchanger of the pad temperature adjusting device is inevitably in contact with the polishing liquid during polishing of the substrate, dirt including abrasive grains and abrasive powder of the polishing pad, and the like contained in the polishing liquid is attached to the heat exchanger. When the dirt falls from the heat exchanger during polishing of the substrate, the substrate is contaminated, and defects such as scratches are generated on the substrate.

[0011] Further, the control method of the conventional pad temperature adjusting device simultaneously controls two opposite parameters, that is, the flow rate of the heating liquid and the flow rate of the cooling liquid, and thus is a relatively complicated control method. Therefore, it is desired to more simply control the surface temperature of the polishing pad, and thus to improve the control responsiveness of the surface temperature of the polishing pad. SUMMARY

[0012] Therefore, an object of the present application is to provide a pad temperature adjusting device and a pad temperature adjusting method which improve the control responsiveness of the surface temperature of a polishing pad, and which are capable of adjusting the surface temperature of the polishing pad without generating defects such as scratches and contamination on a substrate. Further, an object of the present application is to provide a polishing device in which such a pad temperature adjusting device is incorporated.

[0013] Technical means for solving the technical problem

[0014] In one embodiment, a pad temperature adjusting device which adjusts the surface temperature of a polishing pad to a prescribed target temperature includes a heat exchanger disposed above the polishing pad and maintained at a prescribed temperature, a pad temperature measurer which measures the surface temperature of the polishing pad, at least one distance sensor which measures the distance between the polishing pad and the heat exchanger, an up-and-down moving mechanism which moves the heat exchanger up and down with respect to the polishing pad, and a control device which controls the operation of the up-and-down moving mechanism based on the measurement value of the pad temperature measurer.

[0015] In one embodiment, the heat exchanger includes a heating flow path formed inside the heat exchanger, and a heating liquid maintained at a prescribed temperature is supplied to the heating flow path at a prescribed flow rate.

[0016] In one embodiment, the pad temperature adjusting device further includes a cooling mechanism which cools the surface of the polishing pad, and the control device operates the cooling mechanism when the target temperature is lower than the measurement value of the pad temperature measurer after the up-and-down moving mechanism reaches the upper limit of movement of the heat exchanger.

[0017] In one embodiment, the cooling mechanism is formed inside the heat exchanger, and includes a cooling flow path to which a cooling fluid is supplied, and the control device controls the flow rate of the cooling fluid based on the measurement value of the pad temperature measurer.

[0018] In one embodiment, the control device includes a storage unit that stores a learning completed model constructed by machine learning using training data including at least a combination of a distance between the heat exchanger and the polishing pad and a temperature of a surface of the polishing pad corresponding to the distance, and a processing unit that inputs a temperature control parameter including at least the target temperature and a measured value of the pad temperature measurer into the learning completed model and executes an operation for outputting an operation amount of the up-and-down movement mechanism.

[0019] In one embodiment, a pad temperature adjustment method is provided for adjusting a surface temperature of a polishing pad to a prescribed target temperature, a surface temperature of the polishing pad is measured, and a heat exchanger disposed above the polishing pad and maintained at a prescribed temperature is moved up and down relative to the polishing pad in accordance with the surface temperature of the polishing pad, thereby adjusting the surface temperature of the polishing pad to the target temperature.

[0020] In one embodiment, in order to maintain the heat exchanger at the prescribed temperature, a heating liquid maintained at a prescribed temperature is supplied to a heating flow path formed inside the heat exchanger at a prescribed flow rate.

[0021] In one embodiment, when the target temperature is lower than a measured value of a pad temperature measurer that measures the surface temperature of the polishing pad after the heat exchanger reaches an upper limit of movement, a cooling mechanism is used to cool the surface of the polishing pad.

[0022] In one embodiment, the step of cooling the surface of the polishing pad is a step of controlling a flow rate of a cooling fluid flowing in a cooling flow path formed inside the heat exchanger based on a measured value of the pad temperature measurer.

[0023] In one embodiment, a learning completed model is constructed by machine learning using training data including at least a combination of a distance between the heat exchanger and the polishing pad and a temperature of a surface of the polishing pad corresponding to the distance, a temperature control parameter including at least the target temperature and a measured value of the pad temperature measurer is input into the learning completed model, and the learning completed model is caused to output an operation amount of the up-and-down movement mechanism.

[0024] In one embodiment, a polishing device is provided that includes a polishing table that supports a polishing pad, a polishing head that presses a substrate against the polishing pad, a pad temperature measurer that measures a surface temperature of the polishing pad, and the above-described pad temperature adjustment device.

[0025] Effects of the Invention

[0026] According to the present invention, the heat exchanger is positioned above the polishing pad, preventing contaminants such as abrasive particles in the polishing slurry and abrasive powder from the polishing pad from adhering to the heat exchanger. This prevents defects such as scratches and contamination of the substrate. Furthermore, the control device only controls the distance of the heat exchanger from the polishing pad to ensure that the surface temperature of the polishing pad is consistent with the target temperature. This allows for simple control to improve the responsiveness of the polishing pad's surface temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram showing a polishing device according to one embodiment.

[0028] Figure 2 It is a horizontal cross-sectional view showing a heat exchanger according to one embodiment.

[0029] Figure 3 This is a schematic diagram showing how the mat surface temperature is regulated by a heat exchanger.

[0030] Figure 4 This is a graph showing an example of the relationship between the distance between the heat exchanger and the polishing pad and the pad surface temperature.

[0031] Figure 5 This is a schematic diagram showing how the coolant supply system is operated to adjust the pad surface temperature.

[0032] Figure 6 This is a schematic diagram showing how the mat surface temperature is adjusted by a heat exchanger according to another embodiment.

[0033] Figure 7 This is a schematic diagram further illustrating how the mat surface temperature is adjusted by a heat exchanger according to another embodiment.

[0034] Figure 8 This is a schematic diagram showing an example of a control device that executes machine learning to construct a learned model that predicts an appropriate operation amount of a vertical movement mechanism.

[0035] Figure 9 This is a schematic diagram showing an example of the structure of a neural network.

[0036] Figure 10 (a) and Figure 10 (b) is an expanded diagram for explaining a simple recursive network as an example of a recursive neural network.

[0037] Figure 11 This is a schematic diagram showing an example of a polishing apparatus including a pad height measuring device for obtaining the profile of the polishing pad.

[0038] Explanation of symbols

[0039] 1 Grinding head

[0040] 2 grinding tables

[0041] 3 polishing pads

[0042] 4 Grinding fluid supply nozzle

[0043] 11 Heat exchanger

[0044] 14 Distance Sensor

[0045] 17 Gas injection nozzle (cooling mechanism)

[0046] 18 Heater

[0047] 19 Heat Lamp

[0048] 23 Cooling fan (cooling mechanism)

[0049] 30 Heating liquid supply mechanism

[0050] 39 Pad Thermometer

[0051] 40 Control Device

[0052] 40a Storage device

[0053] 40b Processing device

[0054] 50 Coolant supply mechanism

[0055] 71 Up and down movement mechanism

[0056] 74 actuator DETAILED DESCRIPTION

[0057] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0058] Figure 1 Schematic diagram of a grinding device according to one embodiment. Figure 1 As shown, the polishing apparatus includes a polishing head 1 that holds and rotates a wafer W, an example of a substrate; a polishing table 2 that supports a polishing pad 3; a polishing liquid supply nozzle 4 that supplies a polishing liquid (e.g., slurry) to the surface of the polishing pad 3; and a pad temperature control device 5 that controls the surface temperature of the polishing pad 3. The surface (upper surface) of the polishing pad 3 constitutes a polishing surface for polishing the wafer W.

[0059] The polishing head 1 is movable in the plumb direction and is rotatable in the direction indicated by the arrow with the axis of the polishing head 1 as the center. The wafer W is held on the lower surface of the polishing head 1 by vacuum suction or the like. The polishing table 2 is connected to a motor (not shown) and is rotatable in the direction indicated by the arrow. As shown in Figure 1

[0060] Figure 1 The polishing apparatus shown further includes a dresser 20 that dresses the polishing pad 3 on the polishing table 2. The dresser 20 is configured to oscillate in the radial direction of the polishing pad 3 on the surface of the polishing pad 3. The lower surface of the dresser 20 constitutes a dressing surface composed of a large number of abrasive grains such as diamond particles. The dresser 20 oscillates and rotates on the polishing surface of the polishing pad 3, and dresses the surface of the polishing pad 3 by slightly grinding the polishing pad 3.

[0061] The polishing of the wafer W is performed in the following manner. The wafer W to be polished is held by the polishing head 1 and is further rotated by the polishing head 1. On the other hand, the polishing pad 3 is rotated together with the polishing table 2. In this state, the polishing liquid is supplied from the polishing liquid supply nozzle 4 to the surface of the polishing pad 3, and the surface of the wafer W is pressed to the surface (i.e., the polishing surface) of the polishing pad 3 by the polishing head 1. The surface of the wafer W is polished by being brought into sliding contact with the polishing pad 3 in the presence of the polishing liquid. The surface of the wafer W is planarized by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid.

[0062] The pad temperature adjusting device 5 includes a heat exchanger 11 disposed above the polishing pad 3, a pad temperature measurer 39 that measures the surface temperature of the polishing pad 3 (hereinafter, referred to as the pad surface temperature), a heated liquid supply system 30 that supplies a heated liquid adjusted to a prescribed temperature to the heat exchanger 11 at a prescribed flow rate, an up-and-down moving mechanism 71 that moves the heat exchanger 11 up and down with respect to the polishing pad 3, and a control device 40 that controls the operation of the up-and-down moving mechanism 71 based on the measurement value of the pad temperature measurer 39. In the present embodiment, the control device 40 is configured to control the operation of the entire polishing apparatus including the pad temperature adjusting device 5.

[0063] Figure 1 ​The illustrated heating liquid control system 30 is provided with a heating liquid supply tank 31 that serves as a heating liquid supply source that stores heating liquid adjusted to a prescribed temperature, and a heating liquid supply pipe 32 and a heating liquid return pipe 33 that link the heating liquid supply tank 31 with the heat exchanger 11. The heating liquid supply pipe 32 and the heating liquid return pipe 33 are connected at one end to the heating liquid supply tank 31 and at the other end to the heat exchanger 11.

[0064] The temperature-adjusted heating liquid is supplied from the heating liquid supply tank 31 to the heat exchanger 11 through the heating liquid supply pipe 32, and flows within the heat exchanger 11, and then returns from the heat exchanger 11 to the heating liquid supply tank 31 through the heating liquid return pipe 33. In this way, the heating liquid circulates between the heating liquid supply tank 31 and the heat exchanger 11. In the present embodiment, a heating source (e.g., a heater) 48 is provided in the heating liquid supply tank 31. The heating liquid stored in the heating liquid supply tank 31 is heated to a prescribed temperature (set temperature) by the heating source 48.

[0065] A first on-off valve (heating liquid supply valve) 41 and a first flow control valve (heating liquid flow control valve) 42 are installed in the heating liquid supply pipe 32. The first flow control valve 42 is provided between the heat exchanger 11 and the first on-off valve 41. The first on-off valve 41 is a valve that does not have a flow rate adjustment function, in contrast to the first flow control valve 42, which is a valve that has a flow rate adjustment function. The first flow control valve 42 is connected to the control device 40, and adjusts the flow rate of the heating liquid supplied to the heat exchanger 11 to a prescribed flow rate (set flow rate).

[0066] Warm water is used as the heating liquid supplied to the heat exchanger 11. The warm water is heated to a set temperature of, for example, approximately 80°C by the heating source 48 of the heating liquid supply tank 31. In the case where the temperature of the heating liquid is set to a higher temperature, silicon oil can also be used as the heating liquid. In the case where silicon oil is used as the heating liquid, the silicon oil is heated to a set temperature of 100°C or higher (e.g., approximately 120°C) by the heating source 48 of the heating liquid supply tank 31.

[0067] In this way, since the heating liquid that is adjusted to a prescribed temperature and flows at a prescribed flow rate is supplied to the heat exchanger 11, the temperature of the heat exchanger 11 is maintained at a constant temperature. The heat exchanger 11 is provided above the polishing pad 3, and the surface of the polishing pad 3 is heated by the radiant heat from the heat exchanger 11.

[0068] Although described in detail later, as Figure 1As shown, the pad temperature adjusting device 5 can also have a coolant supply system 50 that supplies coolant to the heat exchanger 11. The coolant supply system 50 functions as a cooling mechanism that cools the surface of the polishing pad 3. In the following description, an embodiment of the pad temperature adjusting device 5 including the coolant supply system 50 is described, but the pad temperature adjusting device 5 can omit the coolant supply system 50.

[0069] The coolant supply system 50 has a coolant supply pipe 51 and a coolant discharge pipe 52 that are connected to the heat exchanger 11. The coolant supply pipe 51 is connected to a coolant supply source (for example, a cold water supply source) that is provided at a factory where the polishing device is installed. Coolant is supplied to the heat exchanger 11 through the coolant supply pipe 51, flows within the heat exchanger 11, and is then discharged from the heat exchanger 11 through the coolant discharge pipe 52. In an embodiment, the coolant that flows within the heat exchanger 11 can be returned to the coolant supply source through the coolant discharge pipe 52.

[0070] The second on-off valve (coolant supply valve) 55 and the second flow control valve (coolant flow control valve) 56 are installed in the coolant supply pipe 51. The second flow control valve 56 is disposed between the heat exchanger 11 and the second on-off valve 55. The second on-off valve 55 is a valve that does not have a flow rate adjustment function, in contrast to the second flow control valve 56, which is a valve that has a flow rate adjustment function. The control device 40 is connected to the second flow control valve 56 and can adjust the flow rate of the coolant supplied to the heat exchanger 11.

[0071] Cold water or silicone oil is used as the coolant supplied to the heat exchanger 11. In the case of using silicone oil as the coolant, the polishing pad 3 can be rapidly cooled by connecting a cooling machine that is a coolant supply source to the coolant supply pipe 51 and cooling the silicone oil to 0°C or less. Pure water can be used as the cold water. A cooling machine can be used as the coolant supply source to generate cold water in order to cool the pure water. In this case, the cold water that flows within the heat exchanger 11 can be returned to the cooling machine through the coolant discharge pipe 52.

[0072] The coolant supply pipe 51 of the coolant supply system 50 and the heating liquid supply pipe 32 of the heating liquid supply system 30 are completely independent pipes. Therefore, the heating liquid and the coolant can be simultaneously supplied to the heat exchanger 11 without mixing. The coolant discharge pipe 52 and the heating liquid return pipe 33 are also completely independent pipes. Therefore, the heating liquid is returned to the heating liquid supply tank 31 without mixing with the coolant, and the coolant is discharged without mixing with the heating liquid or is returned to the coolant supply source.

[0073] Figure 2 FIG. 7 is a horizontal sectional view of the heat exchanger 11 that shows an embodiment. Figure 2The heat exchanger 11 shown has a heating flow path 61 and a cooling flow path 62 formed inside the heat exchanger 11. The heating flow path 61 and the cooling flow path 62 extend adjacent to (side by side with) each other and extend in a spiral shape. The heating flow path 61 and the cooling flow path 62 are completely separated and the heating liquid and the cooling liquid do not mix within the heat exchanger 11.

[0074] The heating liquid supply pipe 32 is connected to the inlet 61a of the heating flow path 61 and the heating liquid return pipe 33 is connected to the outlet 61b of the heating flow path 61. The cooling liquid supply pipe 51 is connected to the inlet 62a of the cooling flow path 62 and the cooling liquid discharge pipe 52 is connected to the outlet 62b of the cooling flow path 62. The heating flow path 61 and the cooling flow path 62 are each substantially composed of a plurality of circular arc flow paths 64 having a constant curvature and a plurality of inclined flow paths 65 connecting the circular arc flow paths 64. Two adjacent circular arc flow paths 64 are connected by each inclined flow path 65. According to such a structure, the outermost portions of the heating flow path 61 and the cooling flow path 62 can be disposed at the outermost portions of the pad contact member 11. That is, substantially the entire pad contact surface composed of the lower surface of the pad contact member 11 is located below the heating flow path 61 and the cooling flow path 62 and the heating liquid and the cooling liquid can rapidly heat and cool the surface of the polishing pad 3.

[0075] Returning to Figure 1 , the pad temperature measurer 39 of the pad temperature adjusting device 5 is disposed above the surface of the polishing pad 3 to measure the surface temperature of the polishing pad 3 in a non-contact manner. The pad temperature measurer 39 is connected to the control device 40 and transmits its measurement value to the control device 40.

[0076] The pad temperature measurer 39 can be an infrared radiation thermometer or a thermocouple thermometer that measures the surface temperature of the polishing pad 3 or can be a temperature distribution measurer that acquires the temperature distribution (temperature profile) of the polishing pad 3 along the radial direction of the polishing pad 3. A thermal imager, a thermopile, and an infrared camera device are cited as examples of the temperature distribution measurer. In the case where the pad temperature measurer 39 is the temperature distribution measurer, the pad temperature measurer 39 is configured to measure the distribution of the surface temperature of the polishing pad 3 in a region including the center and the outer periphery of the polishing pad 3, that is, to measure the distribution of the surface temperature of the polishing pad 3 in a region extending in the radial direction of the polishing pad 3. In this specification, the temperature distribution (temperature profile) indicates the relationship between the pad surface temperature and the position in the radial direction on the wafer W.

[0077] The up-and-down moving mechanism 71 of the pad temperature adjusting device 5 is a device that moves the heat exchanger 11 in the up-and-down direction with respect to the polishing pad 3 within a range in which the heat exchanger 11 does not come into contact with the surface of the polishing pad 3. The up-and-down moving mechanism 71 at least has an actuator 74 that can move the heat exchanger 11 in the up-and-down direction.

[0078] Figure 1The vertical movement mechanism 71 shown includes a support member 73 connected to the heat exchanger 11 and an actuator 74 that moves the heat exchanger 11 up and down via the support member 73. The structure of the actuator 74 can be any as long as it can move the heat exchanger 11 in the vertical direction. For example, the actuator 74 can be a piston-cylinder device with a piston that moves the heat exchanger 11 up and down via the support member 73, or the actuator 74 can be a motor (for example, a servo motor or a stepping motor) that moves the heat exchanger 11 up and down via the support member 73. In one embodiment, the actuator 74 can also be a piezoelectric actuator that uses the piezoelectric effect of a piezoelectric element to move the heat exchanger 11 up and down via the support member 73.

[0079] The vertical movement mechanism 71 is connected to the control device 40. The control device 40 controls the movement of the vertical movement mechanism 71 (i.e., the amount of operation of the actuator 74) based on the measurement value of the pad temperature measuring device 39, thereby controlling the vertical position of the heat exchanger 11 relative to the polishing pad 3. As described above, the heat exchanger 11 is heated to a predetermined temperature and maintained at that predetermined temperature. Therefore, when the heat exchanger 11 is brought closer to the polishing pad 3, the pad surface temperature can be increased. When the heat exchanger 11 is moved away from the polishing pad 3, the pad surface temperature decreases.

[0080] Figure 3 Schematic diagram showing how the mat surface temperature is regulated by the heat exchanger 11 . Figure 4 : is a graph showing an example of the relationship between the distance between the heat exchanger 11 and the polishing pad 3 and the pad surface temperature. In the following description, the distance between the heat exchanger 11 and the polishing pad 3 is sometimes referred to as "separation distance". Figure 4 In FIG. 1 , the vertical axis represents the temperature of the surface of the polishing pad 3 (ie, the pad surface temperature), and the horizontal axis represents the separation distance. Figure 4 The graph shown shows an example of the pad surface temperature that changes when the heat exchanger 11 maintained at a predetermined temperature is moved relative to the polishing pad 3 .

[0081] The control device 40 pre-stores the relationship between the spacing distance and the pad surface temperature. For example, the control device 40 pre-stores Figure 4 In one embodiment, the control device 40 may also pre-store the relationship between the spacing distance and the pad surface temperature. Figure 4 The graph shown is obtained from the data table of standoff distance vs. pad surface temperature. Figure 4 The graph shown can be obtained through experiments or simulations.

[0082] The pad temperature control device 5 has at least one distance sensor 14, which can measure the distance between the heat exchanger 11 and the surface of the polishing pad 3.Figure 1 and Figure 3 In the illustrated embodiment, the distance sensor 14 is mounted on the outer surface of the heat exchanger 11. The distance sensor 14 is also connected to the control device 40 and transmits its measured value to the control device 40.

[0083] As described above, the control device 40 uses the vertical movement mechanism 71 to control the vertical position of the heat exchanger 11 relative to the polishing pad 3 so that the value measured by the pad temperature measuring device 39 matches the predetermined target temperature. The method for adjusting the pad surface temperature by the pad temperature adjustment device 5 will be described in further detail below.

[0084] First, the control device 40 moves the heat exchanger 11 to a distance X1 (see FIG. 1 ) between the heat exchanger 11 and the polishing pad 3 corresponding to the predetermined target temperature T1. Figure 4 Specifically, the control device 40 calculates the movement distance between the heat exchanger 11 and the polishing pad 3 until the distance between the heat exchanger 11 and the polishing pad 3 reaches the separation distance based on the measurement value of the distance sensor 14, and determines the operation amount of the actuator 74 of the vertical movement mechanism 71 corresponding to the obtained movement amount. The control device 40 sends a command to the actuator 74 based on the operation amount of the actuator 74 to move the heat exchanger 11.

[0085] Next, if the value measured by the mat temperature measuring device 39 is higher (lower) than the predetermined target temperature T1, the control device 40 sends a command to the actuator 74 of the vertical movement mechanism 71 to increase (decrease) the separation distance X. In this case, the movement amount of the heat exchanger 11 is determined based on the difference between the target temperature T1 and the value measured by the mat temperature measuring device 39. Specifically, the control device 40 calculates the difference between the target temperature T1 and the value measured by the mat temperature measuring device 39, and Figure 4 The amount of movement of the heat exchanger 11 to make the difference equal to 0 is determined using the graph shown in FIG. 1 or the relationship between the separation distance X and the pad surface temperature obtained from the graph (or a data table). Each time the distance between the heat exchanger 11 and the polishing pad 3 is changed, the control device 40 stores a combination of the separation distance X and the pad surface temperature corresponding to the separation distance X (i.e., the value measured by the pad temperature measuring device 39).

[0086] Thus, in order to adjust the pad surface temperature to the target temperature, the control device 40 changes the interval distance X of the heat exchanger 11 maintained at the prescribed temperature with respect to the polishing pad 3. The heat exchanger 11 is always located above the polishing pad 3, and the control device 40 does not bring the heat exchanger 11 into contact with the polishing pad 3. Therefore, since dirt such as abrasive grains contained in the polishing liquid and abrasive powder of the polishing pad 3 does not adhere to the heat exchanger 11, defects such as scratches and contamination are prevented from being generated on the wafer (substrate) W. Also, in order to adjust the surface temperature of the polishing pad 3 to the target temperature, the control device 40 controls only the distance of the heat exchanger 11 with respect to the polishing pad 3. Therefore, it is possible to improve the control responsiveness of the surface temperature of the polishing pad 3 with simple control.

[0087] The up-and-down movement mechanism 71 has an upper limit and a lower limit of the movement amount of the heat exchanger 11. The lower limit of the movement amount of the heat exchanger 11 (refer to the interval distance Xl in Figure 4 ) is a limit value at which the heat exchanger 11 can approach the surface of the polishing pad 3, and the lower limit is determined in advance. The control device 40 stores in advance the operation amount of the actuator 74 corresponding to the lower limit of the movement amount of the heat exchanger 11, and is configured not to send an instruction exceeding the operation amount to the actuator 74.

[0088] The upper limit of the movement amount of the heat exchanger 11 (refer to the interval distance Xh in Figure 4 ) is, for example, a physical or mechanical action limit value of the up-and-down movement mechanism 71. In the case where other structural elements of the polishing device exist directly above the heat exchanger 11, the upper limit of the movement amount of the heat exchanger 11 is set in advance so that the heat exchanger 11 does not come into contact with the other structural elements. Thus, there is a limit to the distance at which the heat exchanger 11 is moved away from the surface of the polishing pad 3. Therefore, as shown in Figure 4 , when the prescribed target temperature is set to a target temperature T2 that is lower than the pad surface temperature Tc corresponding to the upper limit of the movement of the up-and-down movement mechanism 71 (i.e., the interval distance Xh shown in Figure 4 ), the temperature of the surface of the polishing pad 3 cannot be reduced to the target temperature T2 by the heat exchanger 11 maintained at the prescribed temperature.

[0089] In this case, the control device 40 operates the above-described cooling liquid supply system (cooling mechanism) 50. Figure 5 is a schematic view showing the case where the pad surface temperature is adjusted by operating the cooling liquid supply system 50. As shown in Figure 5 , the temperature of the surface of the polishing pad 3 is adjusted to the target temperature T2 by the cooling liquid supply system 50 (refer to the interval distance X2 in Figure 1cooling liquid is supplied to the heat exchanger 11. In this case, although the heating liquid adjusted to the prescribed temperature is continuously supplied to the heat exchanger 11 at the prescribed flow rate, the temperature of the heat exchanger 11 is lowered by the cooling liquid supplied by the cooling liquid supply system 50. As a result, it is possible to lower the temperature of the surface of the polishing pad 3 to the target temperature T2 below the pad surface temperature Tc.

[0090] The control device 40 adjusts the flow rate of the cooling liquid supplied to the heat exchanger 11 based on the measured value of the pad temperature measurer 39. More specifically, the control device 40 controls the opening degree of the second flow rate control valve 56 (refer to FIG. 2) to adjust the flow rate of the cooling liquid supplied to the heat exchanger 11 so that the measured value of the pad temperature measurer 39 coincides with the target temperature T2. Figure 1

[0091] In the case where the prescribed target temperature is set to the target temperature T2 below the pad surface temperature Tc corresponding to the upper limit of the movement of the up-down movement mechanism 71, the control device 40 does not control the operation amount of the up-down movement mechanism 71 (i.e., the position in the up-down direction of the heat exchanger 11) but controls the flow rate of the cooling liquid. In this case, the parameter controlled by the control device 40 in order to adjust the pad surface temperature to the prescribed target temperature is only the flow rate of the cooling liquid. Therefore, it is possible to improve the control responsiveness of the surface temperature of the polishing pad 3 with simple control.

[0092] Furthermore, the cooling liquid is used only in the case where the prescribed target temperature is set to a temperature below the pad surface temperature Tc corresponding to the upper limit of the movement of the up-down movement mechanism 71. Therefore, the pad temperature adjusting device 5 of the present embodiment can reduce the amount of use of the cooling liquid as compared with the conventional pad temperature adjusting device which always supplies the cooling liquid to the heat exchanger. As a result, since the cost for manufacturing the cooling liquid is reduced, it is possible to reduce the running cost of the pad temperature adjusting device 5.

[0093] Figure 6 is a schematic view showing the case where the pad surface temperature is adjusted by the heat exchanger 11 of another embodiment. The structure of the embodiment not specifically described is the same as that of the above-described embodiment, and thus the repeated description thereof is omitted.

[0094] Figure 6 The heat exchanger 11 shown has a heater 18 instead of the heating liquid supply system 30. The heater 18 is connected to the control device 40. The control device 40 controls the current and voltage supplied to the heater 18 to be constant. Thereby, the heat exchanger 11 is heated to a prescribed temperature, and is maintained at the prescribed temperature.

[0095] In the case where the prescribed target temperature is set to the target temperature T2 below the pad surface temperature Tc corresponding to the upper limit of the movement of the up-down movement mechanism 71, the control device 40 does not control the operation amount of the up-down movement mechanism 71 (i.e., the position in the up-down direction of the heat exchanger 11) but controls the flow rate of the cooling liquid. In this case, the parameter controlled by the control device 40 in order to adjust the pad surface temperature to the prescribed target temperature is only the flow rate of the cooling liquid. Therefore, it is possible to improve the control responsiveness of the surface temperature of the polishing pad 3 with simple control. Figure 6 ​In the illustrated embodiment, instead of the cooling liquid supply system 50, there is provided a gas jet nozzle 17 that jets gas toward the surface of the polishing pad 3. The gas jet nozzle 17 functions as a cooling mechanism that cools the surface of the polishing pad 3.

[0096] In the present embodiment, the pad temperature adjusting device 5 also adjusts the pad surface temperature to a target temperature based on the measured value of the pad temperature measurer 39 by moving the heat exchanger 11 that is maintained at a prescribed temperature up and down with respect to the polishing pad 3. In the case where the prescribed target temperature is set to a target temperature T2 that is lower than the pad surface temperature Tc corresponding to the upper limit of the movement of the up-and-down movement mechanism 71, the gas jet nozzle (cooling mechanism) 17 is activated. The control device 40 controls the flow rate of the gas jetted from the gas jet nozzle 17 based on the measured value of the pad temperature measurer 39.

[0097] Figure 7 is a schematic view that indicates a case where the pad surface temperature is further adjusted by the heat exchanger 11 of another embodiment. The structure of the embodiment not specifically described is the same as that of the above-described embodiment, and thus the repeated description thereof is omitted.

[0098] Figure 7 The heat exchanger 11 illustrated has a heating lamp 19 instead of the heating liquid supply system 30. The heating lamp 19 is connected to the control device 40, and the control device 40 controls the current and voltage supplied to the heating lamp 19 to be constant. Thereby, the heat exchanger 11 is heated to a prescribed temperature, and is maintained at the prescribed temperature.

[0099] In Figure 7 In the illustrated embodiment, instead of the cooling liquid supply system 50, there is provided a cooling fan 23 that generates an airflow toward the surface of the polishing pad 3. The cooling fan 23 functions as a cooling mechanism that cools the surface of the polishing pad 3.

[0100] In the present embodiment, the pad temperature adjusting device 5 also adjusts the pad surface temperature to a target temperature based on the measured value of the pad temperature measurer 39 by moving the heat exchanger 11 that is maintained at a prescribed temperature up and down with respect to the polishing pad 3. In the case where the prescribed target temperature is set to a target temperature T2 that is lower than the pad surface temperature Tc corresponding to the upper limit of the movement of the up-and-down movement mechanism 71, the cooling fan (cooling mechanism) 23 is activated. The control device 40 controls the rotational speed of the cooling fan 23 based on the measured value of the pad temperature measurer 39.

[0101] In one embodiment, it can also be that, Figure 6 The pad temperature adjusting device 5 illustrated has the cooling fan 23 instead of the gas jet nozzle 17. In addition, it can also be that, Figure 7 The pad temperature adjusting device 5 illustrated has the gas jet nozzle 17 instead of the cooling fan 23.

[0102] As long as the distance between the heat exchanger 11 and the surface of the polishing pad 3 can be measured in a non-contact manner, any sensor can be used as the distance sensor 14. As examples of the distance sensor 14, a laser sensor, an ultrasonic sensor, an eddy current sensor, or an electrostatic capacity sensor, and the like are cited. In the embodiment shown in FIGS. 1 to 3, although only one distance sensor 14 is attached to the heat exchanger 11, the pad temperature adjusting device 5 can have a plurality of (for example, four) distance sensors 14 arranged at intervals along the outer peripheral surface of the heat exchanger 11 or the like. In the case where the pad temperature adjusting device 5 has a plurality of distance sensors 14, the control device 40 can use the average of the measured values of the plurality of distance sensors 14 as the interval distance, or can use the maximum (or minimum) value of the measured values of the plurality of distance sensors 14 as the interval distance. Figure 1 and Figure 3 In the embodiment shown in FIGS. 1 to 3, although only one distance sensor 14 is attached to the heat exchanger 11, the pad temperature adjusting device 5 can have a plurality of (for example, four) distance sensors 14 arranged at intervals along the outer peripheral surface of the heat exchanger 11 or the like. In the case where the pad temperature adjusting device 5 has a plurality of distance sensors 14, the control device 40 can use the average of the measured values of the plurality of distance sensors 14 as the interval distance, or can use the maximum (or minimum) value of the measured values of the plurality of distance sensors 14 as the interval distance.

[0103] The control device 40 of the pad temperature adjusting device 5 can also use a learning completed model constructed by performing machine learning to predict or determine an appropriate operation amount of the up-and-down moving mechanism 71 (or an appropriate interval distance between the heat exchanger 11 and the polishing pad 3) for rapidly converging the pad surface temperature to a prescribed target temperature and maintaining at the prescribed target temperature.

[0104] Machine learning is performed by a learning algorithm that is an algorithm of artificial intelligence (AI), and a learning completed model that predicts an appropriate operation amount of the up-and-down moving mechanism 71 is constructed by machine learning. The learning algorithm that constructs the learning completed model is not particularly limited. For example, a publicly known learning algorithm such as "supervised learning", "unsupervised learning", "reinforcement learning", "neural network", and the like can be adopted as the learning algorithm for learning an appropriate operation amount of the up-and-down moving mechanism 71.

[0105] Figure 8 is a schematic view showing an example of the control device 40 that can perform machine learning for constructing a learning completed model. The control device 40 is provided with a storage device 40a that stores programs, data, and a learning completed model, and the like, a processing device 40b such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) that performs arithmetic operation according to the program stored in the storage device 40a, and a machine learner 300 that is linked to the processing device 40b and constructs a learning completed model that predicts an appropriate operation amount of the up-and-down moving mechanism 71. In an embodiment, the machine learner 300 that constructs a learning completed model that predicts an appropriate operation amount of the up-and-down moving mechanism 71 can also be provided separately from the control device 40.

[0106] Figure 8 The illustrated machine learner 300 is an example of a machine learner capable of learning an appropriate operation amount of the up-down movement mechanism 71. The machine learner 300 includes a state observation unit 301, a data acquisition unit 302, and a learning unit 303.

[0107] The state observation unit 301 observes a state variable that is an input value for machine learning. The state variable is a collective term for temperature control parameters related to control of the pad surface temperature. In the present embodiment, the state variable includes at least a measured value of the pad surface temperature acquired by the pad temperature gauge 39 and a measured value of the distance sensor 14 at the time when the pad surface temperature is acquired by the pad temperature gauge 39 (i.e., the interval distance).

[0108] The data acquisition unit 302 acquires movement amount data from the determination unit 310. The movement amount data is data used when constructing a learned model for predicting an appropriate operation amount of the up-down movement mechanism 71, and is data that measures a relationship between a change amount when the interval distance between the heat exchanger 11 maintained at a certain temperature and the polishing pad 3 is changed and a change amount of the temperature of the surface of the polishing pad 3 corresponding to the change amount, according to a publicly known measurement method. The movement amount data is correlated (associated) with the state variable input to the state observation unit 301.

[0109] An example of machine learning performed by the machine learner 300 is performed as follows. First, the state observation unit 301 acquires a state variable including at least the interval distance and the temperature of the surface of the polishing pad 3 corresponding to the interval distance, and the data acquisition unit 302 acquires movement amount data correlated with the state variable acquired by the state observation unit 301. The learning unit 303 learns an appropriate operation amount of the up-down movement mechanism 71 based on a training data set that is a combination of the state variable acquired from the state observation unit 301 and the movement amount data acquired from the data acquisition unit 302. The machine learning performed by the machine learner 300 is repeatedly performed until the machine learner 300 outputs an appropriate operation amount of the up-down movement mechanism 71.

[0110] In one embodiment, the machine learning performed by the learning unit 303 of the machine learner 300 can also be machine learning using a neural network, and in particular, can also be deep learning. Deep learning is a method of machine learning based on a neural network in which a hidden layer (also referred to as an intermediate layer) is multilayered. In the present specification, machine learning using a neural network composed of an input layer, two or more hidden layers, and an output layer is referred to as deep learning.

[0111] Figure 9 is a schematic diagram showing an example of the structure of a neural network. Figure 9The illustrated neural network has an input layer 350, a plurality of hidden layers 351, and an output layer 352. The neural network learns an appropriate operation amount of the up-and-down movement mechanism 71 based on training data sets composed of a large number of combinations of the state variable acquired by the state observation section 301 and the movement amount data related to the state variable acquired by the data acquisition section 302. That is, the neural network learns the relationship between the state variable and the operation amount of the up-and-down movement mechanism 71. Such machine learning is called so-called "supervised learning". In supervised learning, the correlation between the state variable and the movement amount data (label) related to the state variable is learned inductively by inputting a large number of combinations of the state variable and the movement amount data to the neural network.

[0112] In one embodiment, the neural network can also learn an appropriate operation amount of the up-and-down movement mechanism 71 through so-called "unsupervised learning". Unsupervised learning is, for example, learning how a state variable is distributed by inputting a large number of state variables to the neural network without any supervision. Also, in unsupervised learning, even if supervised output data (movement amount data) corresponding to the state variable is not input to the neural network, the input state variable is compressed, classified, shaped, or the like, thereby constructing a learning completed model for outputting an appropriate operation amount of the up-and-down movement mechanism 71. That is, in unsupervised learning, the neural network classifies a large number of input state variables into small groups having certain similar characteristics. Also, the neural network sets a predetermined reference for outputting an appropriate operation amount of the up-and-down movement mechanism 71 for each of the classified small groups, constructs a learning completed model by optimizing the relationship therebetween, and thereby outputs an appropriate operation amount of the up-and-down movement mechanism 71.

[0113] Also, in one embodiment, in order to reflect the change in the state variable over time in the learning completed model, the machine learning performed by the learning section 303 can also use so-called "recurrent neural network (RNN)". The recurrent neural network utilizes not only the state variable at the current time but also the state variable input to the input layer 350 up to the current time. In the recurrent neural network, by expanding and considering the change in the state variable along the time axis, it is possible to construct a learning completed model that estimates an appropriate operation amount of the up-and-down movement mechanism 71 based on the transition of the state variable input up to the current time.

[0114] Figure 10 (a) of FIG. 10 and Figure 10 (b) of FIG. 10 is an expanded diagram for explaining a recurrent neural network (Elman network) as an example of a recurrent neural network. More specifically, Figure 10 (a) of FIG. 10 is a schematic diagram showing the expansion of the time axis of the Elman network, Figure 10(b) is a schematic diagram showing the back propagation time of the error back propagation method (also called "back propagation").

[0115] exist Figure 10 (a) and Figure 10 In the Elman network shown in (b), unlike the usual neural network, the error propagates in a retroactive manner (see Figure 10 By applying such a recursive neural network structure to the neural network of the machine learning performed by the learning unit 303, it is possible to construct a learning completion model that outputs the appropriate operation amount of the vertical movement mechanism 71 based on the transition of the state variables input so far.

[0116] The learning model constructed in this way is stored in the storage device 40a of the control device 40 (see Figure 8 ). The control device 40 operates according to a program electrically stored in the storage device 40a. That is, the processing device 40b of the control device 40 inputs state variables including at least the separation distance sent from the mat temperature measuring device 39 and the distance sensor 14 to the control device 40 and the mat surface temperature corresponding to the separation distance into the input layer 350 of the learning completion model, and predicts the operation amount of the vertical movement mechanism 71 for bringing the mat surface temperature to a predetermined target temperature based on the input state variables (and the amount of change in the state variables over time), and performs a calculation for outputting the predicted operation amount from the output layer 352. The control device 40 moves the heat exchanger 11 in the vertical direction based on the operation amount of the vertical movement mechanism 71 output from the output layer 352. Through such control, the mat surface temperature can be adjusted to the target temperature more quickly and accurately.

[0117] If the amount of operation of the vertical movement mechanism 71 output from the output layer 352 is determined to be equivalent to normal data, the control device 40 may store the amount of operation of the vertical movement mechanism 71 as additional supervisory data in the determination unit 310. In this case, the machine learning device 300 updates the learned model through machine learning based on the supervisory data and the additional supervisory data. This improves the accuracy of the amount of operation of the vertical movement mechanism 71 output from the learned model.

[0118] In one embodiment, some of the following state variables may be selected as state variables to be further input to the state observation unit 301. Alternatively, all of the following state variables may be input to the state observation unit 301.

[0119] (1) Type of polishing pad 3

[0120] (2) Thickness of polishing pad 3

[0121] (3) Wear of polishing pad 3

[0122] (4) Rotational speed of the polishing head 1

[0123] (5) Pressing load of the polishing head 1 (i.e., wafer W) against the polishing pad 3

[0124] (6) Rotational speed of the polishing table 2

[0125] (7) Kind of abrasive grains contained in the polishing liquid (slurry)

[0126] (8) Flow rate of the polishing liquid

[0127] (9) Temperature of the polishing liquid

[0128] (10) Set temperature of the heat exchanger 11

[0129] (11) Temperature of the atmosphere gas in the polishing apparatus

[0130] These state variables (1) to (10) are related to the change in the pad surface temperature. Specifically, when any one of the above state variables (1) to (10) is changed, the amount of frictional heat generated between the wafer W and the polishing pad 3 changes. Therefore, under the condition where any one of the above state variables (1) to (10) is different, even if the heat exchanger 11 heats the surface of the polishing pad 3 at the same interval distance, the pad surface temperature reached is different. The same phenomenon occurs under the condition where the temperature of the atmosphere gas in the polishing apparatus is different.

[0131] Therefore, by further inputting at least one of these state variables (1) to (11) to the state observer 301 and utilizing machine learning for constructing the learning completed model, the learning completed model can output a more accurate operation amount of the up-and-down movement mechanism 71.

[0132] Next, referring to Figure 11 A method of measuring the wear amount of the polishing pad 3 will be described. Figure 11 is a schematic view of an example of a polishing apparatus having a pad height measurer for acquiring the profile of the polishing pad 3.

[0133] Figure 11 The polishing apparatus illustrated in the figure further includes a conditioner device 152 provided to regenerate the surface of the polishing pad 3 deteriorated with repeated polishing of the wafer W, and a pad height measurer 173 installed to the conditioner device 152. As will be described below, the pad height measurer 173 measures the height of the surface of the polishing pad 3, and the control device 40 calculates the wear amount of the polishing pad 3 based on the obtained height of the surface of the polishing pad 3.

[0134] Figure 11The dressing device 152 shown has the above-described dresser 20 (see Figure 1 ) that dresses the surface of the polishing pad 3; a dresser shaft 155 to which the dresser 20 is attached; a cylinder 154 provided at the upper end of the dresser shaft 155; and a dresser arm 157 that rotatably supports the dresser shaft 155. The lower surface of the dresser 20 constitutes a dressing surface that is composed of abrasive grains (e.g., diamond particles). The cylinder 154 is fixed to the dresser arm 157 via a support mechanism that is not shown.

[0135] The dresser arm 157 is driven by a motor that is not shown, and is configured to revolve around a dresser revolving shaft 158. The dresser 20 is rotationally driven together with the dresser shaft 155 by a rotation mechanism that is not shown provided in the dresser arm 157. The cylinder 154 functions as an actuator that presses the dresser 20 against the surface of the polishing pad 3 with a prescribed load (pressing force) via the dresser shaft 155. When the dresser arm 157 revolves around the dresser revolving shaft 158, the dresser 20 oscillates on the surface of the polishing pad 3 in the substantially radial direction of the polishing table 2.

[0136] During the dressing of the polishing pad 3, the dresser 20 is rotated around the dresser shaft 155, and a dressing liquid is supplied from a liquid supply nozzle 174 onto the polishing pad 3. In this state, the dresser 20 is pressed against the polishing pad 3, and the dressing surface (i.e., the lower surface of the dresser 20) is in sliding contact with the surface of the polishing pad 3. Also, the dresser arm 157 is caused to revolve around the dresser revolving shaft 158, so that the dresser 20 oscillates in the radial direction of the polishing pad 3. In this way, the polishing pad 3 is ground by the dresser 20, and the surface of the polishing pad 3 is dressed (regenerated).

[0137] Figure 11 The pad height gauge 173 shown has a pad height sensor 175 for measuring the height of the surface of the polishing pad 3, and a sensor target 176 disposed opposite the pad height sensor 175. The pad height sensor 175 is connected to the control device 40.

[0138] The pad height sensor 175 is fixed to the dresser arm 157, and the sensor target 176 is fixed to the dresser shaft 155. The sensor target 176 moves up and down integrally with the dresser shaft 155 and the dresser 20. On the other hand, the position in the up-and-down direction of the pad height sensor 175 is fixed. The pad height sensor 175 is a displacement sensor, and can indirectly measure the height of the surface of the polishing pad 3 (the thickness of the polishing pad 3) by measuring the displacement of the sensor target 176. Since the sensor target 176 moves up and down integrally with the dresser 20, the pad height sensor 175 can measure the height of the surface of the polishing pad 3 during the dressing of the polishing pad 3. Various types of sensors such as a linear scale sensor, a laser sensor, an ultrasonic sensor, an eddy current sensor, or an electrostatic capacity sensor can be used as the pad height sensor 175.

[0139] The pad height sensor 175 is connected to the control device 40, and transmits the output signal of the pad height sensor 175 (i.e., the measured value of the height of the surface of the polishing pad 3) to the control device 40. The control device 40 can acquire the profile of the polishing pad 3 (the cross-sectional shape of the surface of the polishing pad 3) from the measured value of the height of the surface of the polishing pad 3.

[0140] After the unused polishing pad 3 is attached to the polishing table 2, the control device 40 acquires the initial height of the polishing pad 3 using the pad height measurer 173, and stores the initial height in the storage section 40a (see FIG. 6) (refer to FIG. 7). Figure 8 Every time a prescribed number of wafers W are polished, or the dressing of the polishing pad 3 is performed, the control device 40 measures the height (the wear height) of the polishing pad 3 using the pad height measurer 173. The control device 40 can calculate the wear amount of the polishing pad 3 by subtracting the wear height from the initial height. In this way, the control device 40 can acquire the wear amount of the polishing pad 3 as a state variable input to the state observer 301.

[0141] In the case where the polishing device has the pad height measurer 173, the control device 40 can calculate the interval distance between the polishing pad 3 and the heat exchanger 11 using the pad height sensor 175 instead of the above-described distance sensor 14, and thereby control the operation of the up-and-down moving mechanism 71. In this case, the control device 40 stores the initial position of the heat exchanger 11 with respect to a prescribed reference surface in advance.

[0142] The prescribed reference surface is, for example, the dressing surface of the dresser 20 that retreats above the polishing pad 3 after the dressing is performed. The initial position is, for example, the standby position of the heat exchanger 11 when the polishing of the wafer W is not performed, and every time the polishing of the wafer W is completed, the control device 40 moves the heat exchanger 11 to the initial position using the up-and-down moving mechanism 71.

[0143] As described above, the control device 40 stores the initial height of the polishing pad 3. Therefore, the control device 40 can calculate the distance between the heat exchanger 11 at the initial position and the unused polishing pad 3. Also, the control device 40 can obtain the current height of the polishing pad 3 by bringing the conditioner 20 into contact with the surface of the polishing pad 3 each time the wafer W is polished. That is, the control device 40 can calculate the distance between the heat exchanger 11 at the initial position and the surface of the current polishing pad 3.

[0144] Therefore, the control device 40 can calculate the operation amount of the actuator 74 by subtracting the above interval distance from the distance between the heat exchanger 11 at the initial position and the surface of the current polishing pad 3. According to the present embodiment, the pad height sensor 175 is used as the sensor for bringing the heat exchanger 11 to the interval distance. That is, the pad height sensor 175 is used instead of the above distance sensor 14 that measures the interval distance between the polishing pad 3 and the heat exchanger 11. Therefore, in the case where the polishing device has the pad height measurer 173, since the distance sensor 14 is not needed, the manufacturing cost of the pad temperature adjusting device 5 can be reduced.

[0145] The above-described embodiments are described in order to enable a person having ordinary knowledge in the technical field to which the present application pertains to carry out the present application. Various modifications of the above-described embodiments are conceivable to one skilled in the art, and the technical idea of the present application can be applied to other embodiments. Therefore, the present application is not limited to the described embodiments, but is to be construed as the widest scope defined by the scope of the claims of the present application.

Claims

1. A pad temperature control device for controlling the surface temperature of a polishing pad to a predetermined target temperature, the pad temperature control device comprising: a heat exchanger disposed above the polishing pad and maintained at a predetermined temperature; a pad temperature measuring device for measuring the surface temperature of the polishing pad; at least one distance sensor mounted on an outer surface of the heat exchanger and configured to measure a distance between the polishing pad and the heat exchanger; a vertical movement mechanism for moving the heat exchanger up and down relative to the polishing pad; as well as A control device controls the operation of the vertical movement mechanism based on the measurement value of the mat temperature measuring device and the measurement value of the distance sensor.

2. The pad temperature regulating device according to claim 1, characterized in that The heat exchanger includes a heating flow path formed inside the heat exchanger. A heating liquid maintained at a predetermined temperature is supplied to the heating flow path at a predetermined flow rate.

3. The mat temperature regulating device according to claim 1 or 2, characterized in that further comprising a cooling mechanism for cooling the surface of the polishing pad, The control device operates the cooling mechanism when the target temperature is lower than the measurement value of the mat temperature measuring device after the vertical movement mechanism reaches the upper limit of movement of the heat exchanger.

4. The pad temperature regulating device according to claim 3, characterized in that The cooling mechanism is formed inside the heat exchanger and includes a cooling flow path to which a cooling fluid is supplied. The control device controls the flow rate of the cooling fluid based on the measurement value of the mat temperature measuring device.

5. The mat temperature regulating device according to claim 1 or 2, characterized in that The control device comprises: a storage unit storing a learning model constructed by machine learning using training data, the training data including at least a combination of a distance between the heat exchanger and the polishing pad and a temperature of the surface of the polishing pad corresponding to the distance; as well as A processing device inputs temperature control parameters including at least the target temperature and the measurement value of the mat temperature measuring device into the learned model, and performs calculation for outputting an operation amount of the vertical movement mechanism.

6. A pad temperature adjustment method for adjusting the surface temperature of a polishing pad to a predetermined target temperature, characterized in that: The surface temperature of the polishing pad is measured by a pad temperature measuring device. The distance between the polishing pad and the heat exchanger is measured by a distance sensor mounted on the outer surface of the heat exchanger, the heat exchanger being arranged above the polishing pad and maintained at a predetermined temperature. The heat exchanger is moved up and down relative to the polishing pad by a vertical movement mechanism based on the measurement value of the pad temperature measuring device and the measurement value of the distance sensor, thereby adjusting the surface temperature of the polishing pad to the target temperature.

7. The pad temperature regulation method according to claim 6, characterized in that: In order to maintain the heat exchanger at the predetermined temperature, a heating liquid maintained at the predetermined temperature is supplied at a predetermined flow rate to a heating flow path formed inside the heat exchanger.

8. The pad temperature regulation method according to claim 6 or 7, characterized in that: When the target temperature is lower than the value measured by the pad temperature measuring device after the heat exchanger reaches the upper limit of movement, the surface of the polishing pad is cooled using a cooling mechanism.

9. The pad temperature regulation method according to claim 8, wherein: The step of cooling the surface of the polishing pad is a step of controlling the flow rate of the cooling fluid flowing through the cooling flow path formed inside the heat exchanger based on the measurement value of the pad temperature measuring device.

10. The pad temperature regulation method according to claim 6 or 7, characterized in that: A learning model is constructed by machine learning using training data, the training data including at least a combination of a distance between the heat exchanger and the polishing pad and a temperature of the surface of the polishing pad corresponding to the distance. Temperature control parameters including at least the target temperature and the measurement value of the mat temperature measuring device are input to the learned model, and the learned model is caused to output the operation amount of the vertical movement mechanism.

11. A grinding device, characterized in that: have: A grinding table supporting a grinding pad; a polishing head, the polishing head pressing the substrate against the polishing pad; a pad temperature measuring device for measuring the surface temperature of the polishing pad; as well as A mat temperature regulating device as claimed in any one of claims 1 to 5.

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