Polishing apparatus and polishing method

Abstract

To provide a polishing device which can polish a substrate with desired polishing performance without causing defects such as scratch and contamination on the substrate.SOLUTION: A polishing device includes: a polishing table 2 for supporting a polishing pad 3; a polishing head 1 for pushing a substrate W against a polished surface of the polishing pad 3, and polishing the substrate W; a pad temperature measurement device 10 for measuring the temperature of the polished surface; a pad temperature adjustment device 5 for adjusting a temperature of the polished surface; and a control device 40 for controlling operation of the pad temperature adjustment device 5 based on the temperature of the polished surface measured by the pad temperature measurement device 10. The pad temperature adjustment device 5 includes a pad heating machine 11 which is arranged so as to be separated upward from the polished surface, and the pad heating machine 11 has a long part 11a extending in a substantially radial direction of the polishing pad 3, and a slit-shaped injection port 11b which is formed in the longitudinal direction of the long part 11a, and injects heating fluid toward the polished surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a polishing apparatus and method for polishing a substrate such as a semiconductor wafer by bringing the substrate into sliding contact with a polishing pad, and more particularly to a polishing apparatus and method for polishing the substrate while adjusting the surface temperature of the polishing pad. [Background technology]

[0002] CMP (Chemical Mechanical Polishing) equipment is used in the process of polishing the surface of a substrate in the manufacture of semiconductor devices. The CMP equipment holds the substrate with a polishing head, rotates the substrate, and polishes the substrate surface by pressing the substrate against a polishing pad on a rotating polishing table. During polishing, a polishing liquid (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 the abrasive grains contained in the polishing liquid.

[0003] The polishing rate of a substrate depends not only on the polishing load of the substrate on 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 temperature. Therefore, in the manufacture of semiconductor devices, it is important to maintain the surface temperature of the polishing pad at an optimal value during substrate polishing in order to increase and keep the polishing rate of the substrate constant.

[0004] Therefore, a pad temperature adjustment device for adjusting the surface temperature of a polishing pad has been used in the past (see, for example, Patent Document 1 and Patent Document 2). The pad temperature adjustment device has a pad contact member (or a heat exchanger) that comes into contact with the surface of the polishing pad and is supplied with temperature-adjusted heating liquid and cooling liquid. By adjusting the flow rates of the heating liquid and cooling liquid supplied to the pad contact member, the surface temperature of the polishing pad during substrate polishing can be maintained at a desired temperature. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-176449 A [Patent Document 2] JP 2017-148933 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the pad contact member of the pad temperature adjustment device inevitably comes into contact with the polishing liquid during polishing of the substrate, and therefore, contaminants such as abrasive grains contained in the polishing liquid and wear powder of the polishing pad adhere to the pad contact member. If the contaminants fall off the pad contact member during polishing of the substrate, the substrate may be contaminated or may cause defects such as scratches on the substrate. Furthermore, the contaminants that fall off the pad contact member may deteriorate the surface condition of the polishing pad, which may adversely affect the polishing performance.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a polishing apparatus and a polishing method capable of polishing a substrate with desired polishing performance without causing defects such as scratches and contamination on the substrate. [Means for solving the problem]

[0008] In one aspect, a polishing apparatus is provided, comprising: a polishing table for supporting a polishing pad; a polishing head for pressing a substrate against the polishing surface of the polishing pad to polish the substrate; a pad temperature measuring device for measuring the temperature of the polishing surface; a pad temperature adjusting device for adjusting the temperature of the polishing surface; and a control device for controlling the operation of the pad temperature adjusting device based on the temperature of the polishing surface measured by the pad temperature measuring device, wherein the pad temperature adjusting device includes a pad heater arranged above and spaced apart from the polishing surface, and the pad heater has a long portion extending approximately in the radial direction of the polishing pad and a slit-shaped nozzle formed along the longitudinal direction of the long portion for spraying a heated fluid toward the polishing surface.

[0009] In one embodiment, the pad temperature adjustment device further includes a vertical movement mechanism for moving the pad heater up and down relative to the polishing surface. In one embodiment, the pad temperature adjustment device further includes a rotation mechanism that rotates the pad heater in a horizontal direction relative to the polishing surface. In one aspect, the pad temperature conditioning device further comprises a rotation mechanism for rotating the pad heater about its longitudinal axis.

[0010] In one embodiment, the pad temperature adjusting device further includes a shutter mechanism that adjusts an opening degree of the ejection port. In one aspect, the pad temperature measuring device is a measuring device capable of measuring a temperature profile along the radial direction of the polishing pad, and the shutter mechanism is composed of piezoelectric elements arranged along the longitudinal direction of the nozzle of the pad heater. In one aspect, the control device adjusts the amount of expansion and contraction of each piezoelectric element based on the temperature profile.

[0011] In one embodiment, the pad temperature adjustment device further includes a cooling mechanism that sprays a cooling fluid onto the polishing surface to cool the polishing surface. In one aspect, the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface, and the pad temperature conditioning device further includes a rotation mechanism for rotating the pad cooler about its longitudinal axis. In one aspect, the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface, the pad cooler having a long portion extending approximately in the radial direction of the polishing pad and a plurality of nozzles arranged along the longitudinal direction of the long portion for spraying the cooling fluid toward the polishing surface, and the cooling mechanism further includes a shutter mechanism for adjusting the opening degree of the multiple nozzles of the pad cooler. In one aspect, the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface, and the cooling mechanism further includes a guide plate attached to the pad cooler and an actuator for rotating the guide plate. In one embodiment, the pad temperature adjustment device further includes a suction mechanism disposed above the polishing surface for sucking in air above the polishing surface.

[0012] In one aspect, the pad temperature conditioning device further comprises a heater disposed within the pad heater. In one embodiment, the polishing table is disposed in a polishing chamber, and the pad temperature adjustment device further includes a polishing chamber suction device that sucks air from within the polishing chamber so that the pressure in the polishing chamber is maintained at a predetermined value. In one embodiment, the polishing apparatus further includes a cleaning device that cleans the pad heater at a retreat position to the side of the polishing pad. In one embodiment, the heating fluid is superheated steam.

[0013] In one embodiment, when starting control of the surface temperature of the polishing pad, the control device executes a pad temperature control start operation, and the pad temperature control start operation is an operation of supplying the heating fluid to the pad heater having a flow rate and / or temperature greater than the flow rate and / or temperature of the heating fluid calculated to cause the temperature of the polishing surface to reach a target temperature. In one aspect, the pad temperature adjustment device further includes a heating fluid supply line that supplies the heating fluid to the pad heater, and a flow regulator arranged on the heating fluid supply line, and the control device increases the flow rate of the heating fluid using the flow regulator during the pad temperature adjustment start operation. In one embodiment, the control device terminates the pad temperature adjustment start operation when the temperature of the polishing surface of the polishing pad reaches the target temperature.

[0014] In one aspect, there is provided a polishing method in which a substrate is polished by pressing the substrate against a polishing surface of a polishing pad while adjusting the temperature of the polishing surface of the polishing pad with a pad heater positioned at a distance above the polishing surface, the method comprising the steps of: when starting to control the temperature of the polishing surface, a pad temperature control start operation is performed to cause the temperature of the polishing surface to reach a target temperature; during polishing of the substrate, based on the temperature of the polishing surface measured by a pad temperature measuring device that measures the temperature of the polishing surface, a heating fluid is sprayed from a slit-shaped spray port formed in a long portion of the pad heater to maintain the temperature of the polishing surface at the target temperature; and the pad temperature control start operation is an operation of supplying the heating fluid to the pad heater having a flow rate and / or temperature greater than the flow rate and / or temperature of the heating fluid calculated to cause the temperature of the polishing surface to reach the target temperature.

[0015] In one embodiment, maintaining the temperature of the polishing surface at the target temperature is accomplished by at least one of adjusting the temperature and / or flow rate of the heating fluid, adjusting the vertical movement of the pad heater relative to the polishing surface, adjusting the horizontal rotational movement of the pad heater relative to the polishing surface, and adjusting the rotational movement of the pad heater about its longitudinal axis. In one embodiment, the flow rate of the heating fluid is adjusted by a shutter capable of adjusting the opening of an injection port of the pad heater. In one aspect, the pad temperature measuring device is a measuring device capable of measuring a temperature profile along the radial direction of the polishing pad, the shutter is composed of piezoelectric elements arranged along the longitudinal direction of the nozzle of the pad heater, and the flow rate of the heating fluid is adjusted by adjusting the amount of expansion and contraction of each piezoelectric element based on the temperature profile.

[0016] In one embodiment, the step of maintaining the temperature of the polishing surface at the target temperature is performed by the pad heater and a cooling mechanism that sprays a cooling fluid onto the polishing surface to cool the polishing surface. In one embodiment, the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface, the pad cooler having a long portion extending approximately in the radial direction of the polishing pad and a plurality of nozzles arranged along the longitudinal direction of the long portion for spraying the cooling fluid toward the polishing surface, and the process of maintaining the temperature of the polishing surface at the target temperature is further performed by adjusting at least one of a rotational motion of rotating the pad cooler around its longitudinal axis, adjusting the opening degree of the plurality of nozzles of the pad cooler by a shutter, and adjusting a rotational motion of a guide plate attached to the pad cooler. In one aspect, the pad temperature adjustment start operation is an operation of increasing a flow rate of the heating fluid using a flow regulator arranged in a heating fluid supply line that supplies the heating fluid to the pad heater. In one embodiment, when the temperature of the polishing surface of the polishing pad reaches the target temperature, the pad temperature adjustment start operation is terminated. Effect of the Invention

[0017] According to the present invention, the pad temperature adjustment device adjusts the temperature of the polishing surface of the polishing pad to a predetermined target temperature without contacting the polishing surface of the polishing pad, so that the pad temperature adjustment device does not have any components to which dirt such as abrasive grains contained in the polishing liquid and wear powder of the polishing pad adhere. As a result, defects such as scratches and contamination caused by dirt that has fallen off the pad temperature adjustment device are prevented from occurring on the substrate. Furthermore, the surface condition of the polishing pad is not changed by the dirt that has fallen off the pad temperature adjustment device, so that the substrate can be polished at a desired polishing rate that is achieved when the temperature of the polishing surface of the polishing pad is maintained at a predetermined target temperature. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing a polishing apparatus according to one embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a heating fluid supply system and a cooling fluid supply system according to one embodiment. [Diagram 3]Figure 3(a) is a schematic diagram showing a pad heater according to one embodiment, Figure 3(b) is a cross-sectional view of the pad heater shown in Figure 3(a), and Figure 3(c) is a top view showing an example of the arrangement of the pad heater relative to the polishing pad 3. [Figure 4] FIG. 4(a) is a schematic diagram of a pad cooler according to one embodiment, and FIG. 4(b) is a cross-sectional view of the pad cooler shown in FIG. 4(a). [Diagram 5] FIG. 5(a) is a schematic diagram of a suction nozzle according to one embodiment, and FIG. 5(b) is a cross-sectional view of the suction nozzle shown in FIG. 5(a). [Figure 6] FIG. 6(a) is a diagram showing an example in which the long portion of the pad heating machine and the long portion of the pad cooling machine are formed integrally, and FIG. 6(b) is a schematic diagram showing an example in which a common long portion is provided that functions as both the long portion of the pad heating machine and the long portion of the pad cooling machine. [Figure 7] FIG. 7 is a schematic diagram showing an example of a vertical movement mechanism. [Figure 8] FIG. 8(a) is a schematic diagram showing an example of a rotation mechanism, and FIG. 8(b) is a top view showing the pad heater rotated by the rotation mechanism. [Figure 9] Figure 9(a) is a schematic diagram showing an example of a rotation mechanism for rotating a pad heater around its longitudinal axis, Figure 9(b) is a cross-sectional view showing the pad heater shown in Figure 9(a) when rotated upward, and Figure 9(c) is a cross-sectional view showing the pad heater shown in Figure 9(a) when rotated downward. [Figure 10] FIG. 10 is a cross-sectional view that illustrates a pad heater according to another embodiment. [Figure 11] FIG. 11(a) is a perspective view of a shutter mechanism according to another embodiment viewed from the bottom side, and FIG. 11(b) is a schematic diagram showing an example of the operation of the shutter mechanism shown in FIG. 11(a). [Figure 12] FIG. 12 is a graph showing an example of a target temperature profile of a polishing pad and a temperature profile acquired by a pad temperature measuring device. [Figure 13]FIG. 13 is a cross-sectional view that illustrates a pad heater according to still another embodiment. [Figure 14] FIG. 14 is a schematic diagram showing a polishing apparatus equipped with a pad temperature adjustment device according to still another embodiment. [Figure 15] FIG. 15(a) is a schematic diagram showing a pad cooler of a cooling mechanism according to another embodiment, and FIG. 15(b) is a cross-sectional view of the pad cooler shown in FIG. 15(a). [Figure 16] FIG. 16 is a cross-sectional view that illustrates a pad cooler of a cooling mechanism according to still another embodiment. [Figure 17] FIG. 17 is a schematic diagram showing a pad cooler of a cooling mechanism according to still another embodiment. [Figure 18] FIG. 18 is a graph for explaining an example of the pad temperature adjustment starting operation. [Figure 19] FIG. 19 is a schematic diagram showing a polishing apparatus equipped with a pad temperature adjustment device according to still another embodiment. [Figure 20] FIG. 20 is a schematic diagram showing a heating fluid supply system and a cooling fluid supply system according to another embodiment. [Figure 21] FIG. 21 is a schematic diagram showing a heated fluid supply system according to still another embodiment. [Figure 22] FIG. 22 is a schematic diagram showing a combination of a cooling fluid supply system and a suction mechanism according to another embodiment. [Figure 23] FIG. 23 is a schematic diagram showing a combination of a heating fluid supply system, a cooling fluid supply system, and a suction mechanism according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing a polishing apparatus according to one embodiment. The polishing apparatus shown in Fig. 1 includes a polishing head 1 that holds and rotates a wafer W, which is 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., a slurry) to the surface of the polishing pad 3, a pad temperature measuring device 10 that measures the temperature of the surface of the polishing pad 3, and a pad temperature adjusting device 5 that adjusts 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.

[0020] Furthermore, the polishing apparatus has a control device 40 that controls the operation of the pad temperature adjusting device 5 based on the temperature of the polishing surface of the polishing pad 3 (hereinafter sometimes referred to as the pad surface temperature) measured by the pad temperature measuring device 10. In this embodiment, the control device 40 is configured to control the operation of the entire polishing apparatus including the pad temperature adjusting device 5.

[0021] The polishing head 1 is movable in the vertical direction and can rotate around its axis in the direction indicated by the arrow. The wafer W is held on the underside of the polishing head 1 by vacuum suction or the like. A motor (not shown) is connected to the polishing table 2, and the polishing table 2 can rotate in the direction indicated by the arrow. As shown in FIG. 1, the polishing head 1 and the polishing table 2 rotate in the same direction. The polishing pad 3 is affixed to the upper surface of the polishing table 2.

[0022] Polishing of the wafer W is performed as follows. The wafer W to be polished is held by and rotated by the polishing head 1. Meanwhile, the polishing pad 3 is rotated together with the polishing table 2. In this state, a polishing liquid is supplied to the surface of the polishing pad 3 from a polishing liquid supply nozzle 4, and the surface of the wafer W is pressed against the surface of the polishing pad 3 (i.e., the polishing surface) by the polishing head 1. The surface of the wafer W is polished by 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.

[0023] The pad temperature adjustment device 5 has a heating mechanism 9 that heats the polishing surface of the polishing pad 3, and this heating mechanism 9 includes at least a pad heater 11 arranged above the polishing pad 3 and a heating fluid supply system 30 that supplies heating fluid to the pad heater 11. The heating fluid supplied to the pad heater 11 via the heating fluid supply system 30 is sprayed onto the polishing surface of the polishing pad 3, thereby heating the polishing surface to a predetermined target temperature and maintaining it at the target temperature.

[0024] Furthermore, the pad temperature adjustment device 5 shown in Figure 1 has a cooling mechanism 50 for spraying a fluid onto the polishing surface of the polishing pad 3 to cool the polishing surface, and a suction mechanism 60 arranged above the polishing surface of the polishing pad 3.

[0025] The cooling mechanism 50 has at least a pad cooler 51 arranged above the polishing pad 3 and a cooling fluid supply system 52 that supplies cooling fluid to the pad cooler 51. The suction mechanism 60 has at least a suction nozzle 61 arranged above the polishing pad 3, a vacuum source (vacuum device) 63, and a suction line 62 that connects the vacuum source 63 to the suction nozzle 61. Examples of the vacuum source 63 include a suction pump, a suction fan, and an ejector. The suction mechanism 60 may have a flow regulator 64 arranged in the suction line 62. The flow regulator 64 is, for example, a damper.

[0026] The pad temperature measuring device 10 measures the pad surface temperature in a non-contact manner and sends the measured value to the control device 40. The pad temperature measuring device 10 may be an infrared radiation thermometer or a thermocouple thermometer that measures the surface temperature of the polishing pad 3, or may be a temperature distribution measuring device that obtains the temperature distribution (temperature profile) of the polishing pad 3 along the radial direction of the polishing pad 3. Examples of the temperature distribution measuring device include a thermograph, a thermopile, and an infrared camera. When the pad temperature measuring device 10 is a temperature distribution measuring device, the pad temperature measuring device 10 is configured to measure the distribution of the surface temperature of the polishing pad 3 in a region that includes the center and the outer periphery of the polishing pad 3 and extends 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 radial position on the wafer W.

[0027] The control device 40 controls the operation of the pad temperature adjustment device 5 based on the measured pad surface temperature so that the pad surface temperature is maintained at a preset target temperature. In the following, an example will be described in which the heating fluid supplied from the heating fluid supply system 30 to the pad heater 11 is superheated steam. However, the heating fluid is not limited to this example. The heating fluid may be a high-temperature gas (e.g., high-temperature air, nitrogen, or argon) or may be heated steam. Note that superheated steam means high-temperature steam obtained by further heating saturated steam.

[0028] Further, in the following, an example will be described in which the cooling fluid is a gas at room temperature (e.g., an inert gas such as nitrogen or argon). However, the cooling fluid is not limited to this example. The cooling fluid may be a gas cooled to a set temperature lower than room temperature, or a gas heated from room temperature to a set temperature lower than the target temperature of the polishing pad 3. Taking into account the effect on the polishing liquid, the cooling fluid is preferably an inert gas. However, the cooling fluid may be a gas other than an inert gas such as air.

[0029] FIG. 2 is a schematic diagram showing a heating fluid supply system and a cooling fluid supply system according to one embodiment.

[0030] 2 includes a superheated steam generator 31, a superheated steam supply line 32 extending from the superheated steam generator 31 to the pad heater 11, a water supply line 33 for supplying water to the superheated steam generator 31, and a gas supply line 34 for supplying room temperature gas to the superheated steam generator 31. The gas supply line 34 branches off from a gas main line 70 extending from a gas supply source (not shown) and extends to the superheated steam generator 31.

[0031] The superheated steam generator 31 mixes water supplied from a water supply line 33 with room temperature gas supplied from a gas supply line 34 to generate superheated steam adjusted to a predetermined temperature. The superheated steam is supplied to the pad heater 11 via a superheated steam supply line 32, and is sprayed from the pad heater 11 onto the polishing surface of the polishing pad 3. This operation can increase the temperature of the polishing surface of the polishing pad 3.

[0032] The heating fluid supply system 30 shown in Fig. 2 further includes a flow regulator (first flow regulator) 35 disposed in the superheated steam supply line 32, and an exhaust line 36 branching off from the superheated steam supply line 32 upstream of the flow regulator 35. Examples of the flow regulator 35 include a mass flow controller and a flow control valve. The flow regulator 35 can adjust the flow rate of the superheated steam supplied to the pad heater 11. Excess superheated steam is exhausted from the polishing apparatus through the exhaust line 36.

[0033] In one embodiment, the heating fluid supply system 30 may have an on-off valve (not shown) instead of the flow rate regulator 35. In this case, the control device 40 opens the on-off valve, whereby a predetermined flow rate of superheated steam (heating fluid) is supplied to the pad heater 11, and sprayed from the pad heater 11 onto the polishing surface of the polishing pad 3.

[0034] When high-temperature gas is used as the heating fluid instead of superheated steam, the water supply line 33 is omitted from the heating fluid supply system 30, and the superheated steam generator 31 is replaced with a heating gas heater. Furthermore, the superheated steam supply line 32 can be read as a heating gas supply line.

[0035] The cooling fluid supply system 52 shown in FIG. 2 includes a cooling gas supply line 53 branching off from the gas main line 70 and extending to the pad cooler 51, and a flow regulator (second flow regulator) 54 disposed on the cooling gas supply line 53. Examples of the flow regulator 54 include a mass flow controller and a flow rate adjustment valve. The flow regulator 54 can adjust the flow rate of the cooling gas supplied to the pad cooler 51. The cooling fluid is supplied to the pad cooler 51 via the cooling gas supply line 53, and is sprayed from the pad cooler 51 onto the polishing surface of the polishing pad 3. This operation can reduce the temperature of the polishing surface of the polishing pad 3.

[0036] In one embodiment, the cooling fluid supply system 52 may have an on-off valve (not shown) instead of the flow rate regulator 54. In this case, the control device 40 opens the on-off valve, so that a predetermined flow rate of cooling gas (cooling fluid) is supplied to the pad cooler 51, and the cooling gas (cooling fluid) is sprayed from the pad cooler 51 onto the polishing surface of the polishing pad 3.

[0037] The control device 40 is connected to the superheated steam generator 31, the flow regulators 35, 54, the vacuum source 63, and the flow regulator 64 (see FIG. 1). The control device 40 controls the operation of at least one of the superheated steam generator 31, the flow regulators 35, 54, the vacuum source 63, and the flow regulator 64 based on the measurement value of the pad temperature measuring device 10, and makes the pad surface temperature match a predetermined target temperature. For example, the control device 40 controls the operation of the flow regulators 35, 54 to adjust the flow rate of the superheated steam and the flow rate of the cooling gas so that the pad surface temperature matches the predetermined target temperature.

[0038] In addition to or instead of the operation of the flow regulators 35 and 54, the control device 40 may control at least one of the operation of the superheated steam generator 31, the operation of the vacuum source 63, and the operation of the flow regulator 64. For example, the control device 40 may adjust the temperature of the superheated steam generated by the superheated steam generator 31, or may control the operation of the vacuum source 63 and / or the flow regulator 64 to adjust the amount of air sucked in. The temperature of the polishing surface can be adjusted by changing the temperature of the superheated steam sprayed onto the polishing surface of the polishing pad 3. Increasing or decreasing the amount of air sucked in by the vacuum source 63 and / or the flow regulator 64 changes the amount of heat of vaporization removed from the slurry on the polishing surface, and as a result, the temperature of the polishing surface can be adjusted.

[0039] In one embodiment, the operation of the vacuum source 63 and / or flow regulator 64 of the suction mechanism 60 may be controlled to increase the amount of air sucked through the suction nozzle 61, thereby allowing the suction mechanism 60 to be used as an auxiliary cooling mechanism for the cooling mechanism 50, or the cooling mechanism 50 may be omitted.

[0040] The pad temperature measuring device 10 (see FIG. 1) measures the pad surface temperature in a non-contact manner and sends the measured value to the control device 40. In this embodiment, the control device 40 performs PID control of at least one manipulated variable among the superheated steam generator 31, the flow regulators 35, 54, the vacuum source 63, and the flow regulator 64 based on the measured pad surface temperature so that the pad surface temperature is maintained at a preset target temperature.

[0041] The method of controlling the temperature of the polishing surface of the polishing pad 3 by the control device 40 is not limited to PID control, and any control method can be used as long as the measured pad surface temperature can be maintained at a target temperature. For example, the control device 40 may have an AI (artificial intelligence) function that predicts or determines at least one of the operation amounts of the superheated steam generator 31, the flow regulators 35 and 54, the vacuum source 63, and the flow regulator 64 using a trained model constructed by performing machine learning.

[0042] FIG. 3(a) is a schematic diagram showing a pad heater according to an embodiment, FIG. 3(b) is a cross-sectional view of the pad heater shown in FIG. 3(a), and FIG. 3(c) is a top view showing an example of the arrangement of the pad heater relative to the polishing pad 3. As shown in FIG. 3(a) to FIG. 3(c), the heater 11 has a long portion 11a extending in a substantially radial direction of the polishing pad 3, and an injection port 11b for injecting a heating fluid toward the polishing surface of the polishing pad 3. A flow path (not shown) for superheated steam is formed inside the long portion 11a. The long portion 11a of the pad heater 11 preferably extends parallel to the polishing surface.

[0043] The ejection port 11b has a slit shape formed along the longitudinal direction of the long portion 11a. The ejection port 11b is preferably oriented obliquely with respect to an imaginary plane P1 that passes through the central axis CL1 of the long portion 11a and extends in a direction perpendicular to the polishing surface of the polishing pad 3 so that the heating fluid collides obliquely with the polishing surface of the polishing pad 3.

[0044] The shape of the long portion 11a is arbitrary as long as it is possible to spray the heated fluid from the nozzle 11b toward the polishing surface of the polishing pad 3. For example, the long portion 11a may have a cylindrical shape, or may have a polygonal cylindrical shape such as a rectangular cylindrical shape or a pentagonal cylindrical shape.

[0045] Fig. 4(a) is a schematic diagram of a pad cooler according to an embodiment, and Fig. 4(b) is a cross-sectional view of the pad cooler shown in Fig. 4(a). The pad cooler 51 shown in Figs. 4(a) and 4(b) has a long portion 51a extending in a substantially radial direction of the polishing pad 3, and a plurality of injection ports 51b for injecting a cooling fluid toward the polishing surface of the polishing pad 3. A flow path (not shown) for a cooling gas is formed inside the long portion 51a. The long portion 51a of the pad cooler 51 preferably extends parallel to the polishing surface.

[0046] The multiple injection ports 51b are arranged along the longitudinal direction of the long portion 51a. In this embodiment, each injection port 51b has a circular shape. It is preferable that the injection ports 51b are obliquely oriented with respect to a plane P2 that passes through the central axis CL2 of the long portion 51a and extends in a vertical direction with respect to the polishing surface of the polishing pad 3 so that the cooling fluid collides obliquely with the polishing surface of the polishing pad 3.

[0047] The shape of the long portion 51a is arbitrary as long as the cooling fluid can be sprayed from the nozzle 51b toward the polishing surface of the polishing pad 3. For example, the long portion 51a may have a cylindrical shape, or a polygonal cylindrical shape such as a rectangular or pentagonal cylindrical shape. Furthermore, the number and shape of the nozzles 51b are also arbitrary. For example, the nozzle 51b may be a single opening having a slit shape formed along the longitudinal direction of the long portion 51a, or each of the multiple nozzles 51b may have a rectangular or triangular shape.

[0048] FIG. 5(a) is a schematic diagram of a suction nozzle according to an embodiment, and FIG. 5(b) is a cross-sectional view of the suction nozzle shown in FIG. 5(a). The suction nozzle 61 shown in FIG. 5(a) and FIG. 5(b) has a long portion 61a extending in a substantially radial direction of the polishing pad 3, and a suction port 61b for sucking air above the polishing surface of the polishing pad 3. The suction port 61b is preferably opposed to the polishing surface. A flow path (not shown) for the sucked air is formed inside the long portion 61a. The long portion 61a of the suction nozzle 61 preferably extends parallel to the polishing surface.

[0049] As long as the suction nozzle 61 can suck in a desired amount of air, the shape of the suction nozzle 61 and the number and shape of the suction ports 61b are also arbitrary. For example, the suction mechanism 60 may have a plurality of suction ports 61b arranged along the longitudinal direction of the long portion 61a. In this case, each suction port 61b may have a circular shape, a rectangular shape, or a triangular shape. Furthermore, although not shown, the suction nozzle 61 may have a dome-shaped tip. In this case, an opening formed at the bottom of the tip of the dome-shaped suction nozzle 61 functions as the suction port 61b. Furthermore, the tip of the dome-shaped suction nozzle 61 may accommodate the long portion 11a of the pad heater 11 and / or the long portion 51b of the pad cooler 51.

[0050] As shown in FIG. 6(a), the long portion 11a of the pad heater 11 and the long portion 51b of the pad cooler 51 may be integrally formed. Alternatively, as shown in FIG. 6(b), the pad temperature adjustment device 5 may have a common long portion 80 that functions as both the long portion 11a of the pad heater 11 and the long portion 51b of the pad cooler 51. In this case, the superheated steam supply line 32 and the cooling gas supply line 53 are connected to the common long portion 80 via a mixing valve 81. The control device 40 adjusts the valve opening of the mixing valve 81, so that a mixture gas of superheated steam and cooling gas having a desired temperature is supplied to the common long portion 80, and is sprayed from the long portion 80 onto the polishing surface of the polishing pad 3. The long portion 80 has a slit-shaped outlet formed along the longitudinal direction of the long portion 80, for example.

[0051] When the pad temperature adjustment device 5 has the mixing valve 81, the control device 40 is configured to calculate the operation amount of the mixing valve 81 required to eliminate the difference between a preset target temperature and the surface temperature of the polishing pad 3. The valve opening degree of the mixing valve 81 corresponds to the mixture ratio of the superheated steam and the cooling gas. The control device 40 adjusts the mixture ratio of the superheated steam and the cooling gas by changing the operation amount of the mixing valve 81, and as a result, adjusts the temperature of the mixed gas injected from the injection port of the long portion 80 to the polishing pad 3. The control device 40 controls the operation amount of the mixing valve 81 (i.e., the valve opening degree of the mixing valve 81) so that the surface temperature of the polishing pad 3 coincides with the preset target temperature.

[0052] The pad heater 11, the pad cooler 51, and the suction nozzle 61 may be arranged in any order. However, as shown in Fig. 1, it is preferable that the pad cooler 51 is arranged downstream of the pad heater 11 in the rotation direction of the polishing pad 3, and the suction nozzle 61 is arranged downstream of the pad cooler 51 in the rotation direction of the polishing pad 3. In this case, the pad cooler 51 is located between the pad heater 11 and the suction nozzle 61.

[0053] Furthermore, the pad heater 11, the pad cooler 51, and the suction nozzle 61 are preferably disposed adjacent to each other. In this case, the pad heater 11, the pad cooler 51, and the suction nozzle 61 may be connected to each other by a connector such as a connecting bar, a connecting block, or a connecting arm (none of which are shown). This connector may function as a base that holds the pad heater 11, the pad cooler 51, and the suction nozzle 61 together into an integrated structure.

[0054] According to this embodiment, the pad heater 11, the pad cooler 51, and the suction nozzle 61 are disposed above the polishing pad 3. That is, the pad temperature adjusting device 5 does not have any components to which dirt such as abrasive grains contained in the polishing liquid and wear powder of the polishing pad 3 adhere. As a result, defects such as scratches and contamination caused by dirt falling off the pad temperature adjusting device 5 do not occur on the wafer W. Furthermore, the surface state of the polishing pad 3 is not changed by the dirt falling off the pad temperature adjusting device 5, so the wafer W can be polished at a desired polishing rate.

[0055] 7, the pad temperature adjusting device 5 may include a vertical movement mechanism 85 for moving the pad heater 11 up and down relative to the polishing surface of the polishing pad 3. FIG 7 is a schematic diagram showing an example of the vertical movement mechanism 85.

[0056] The vertical movement mechanism 85 shown in FIG. 7 includes a support arm 86 connected to the pad heater 11, and a vertical movement actuator 87 that moves the pad heater 11 up and down via the support arm 86. The configuration of the vertical movement actuator 87 is arbitrary as long as it is possible to move the pad heater 11 in the vertical direction. For example, the vertical movement actuator 87 may be a piston cylinder device having a piston that moves the pad heater 11 up and down via the support arm 86, or may be a motor (e.g., a servo motor or a stepping motor) that moves the pad heater 11 up and down via the support arm 86. In one embodiment, the vertical movement actuator 87 may be a piezoelectric actuator that uses the piezoelectric effect of a piezoelectric element to move the pad heater 11 up and down via the support arm 86.

[0057] The vertical movement mechanism 85 is connected to the control device 40. The control device 40 controls the operation of the vertical movement mechanism 85 (i.e., the amount of operation of the vertical movement actuator 87) based on the measured value of the pad temperature measuring device 10, and thereby the vertical position of the pad heater 11 with respect to the polishing surface of the polishing pad 3 changes (see arrow A in FIG. 3(b)). When the distance between the pad heater 11 and the polishing pad 3 changes, the temperature of the superheated steam when it collides with the polishing surface of the polishing pad 3 changes. For example, when the pad heater 11 is moved closer to the polishing pad 3, the superheated steam having a higher temperature collides with the polishing surface of the polishing pad 3, and the pad surface temperature can be increased. On the other hand, when the pad heater 11 is moved away from the polishing pad 3, the superheated steam having a lower temperature collides with the polishing surface of the polishing pad 3, and the pad surface temperature can be reduced. Therefore, by changing the distance between the pad heater 11 and the polishing surface of the polishing pad 3, the pad surface temperature can be adjusted.

[0058] Furthermore, as shown in Fig. 8(a), the pad temperature adjustment device 5 may include a rotation mechanism 90 that rotates the pad heater 11 in a horizontal direction relative to the polishing surface of the polishing pad 3. Fig. 8(a) is a schematic diagram showing an example of the rotation mechanism 90, and Fig. 8(b) is a top view showing the pad heater 11 rotated by the rotation mechanism 90.

[0059] The rotation mechanism 90 shown in FIG. 8(a) includes a rotation shaft 91 connected to the pad heater 11 via a support arm 86, and a rotation actuator 92 that rotates the rotation shaft 91. The rotation actuator 92 is, for example, a motor (for example, a servo motor or a stepping motor) that rotates the rotation shaft 91, or a rotary cylinder. In one embodiment, the rotation actuator 92 may be a piston cylinder having a piston. In this case, the rotation mechanism 90 has a link mechanism that converts the movement of the piston of the piston cylinder into the rotational movement of the rotation shaft 91.

[0060] The rotation mechanism 90 is connected to the control device 40. The control device 40 controls the operation of the rotation mechanism 90 (i.e., the amount of operation of the rotation actuator 92) based on the measurement value of the pad temperature measuring device 10, thereby controlling the rotation angle of the pad heater 11 with respect to the polishing surface of the polishing pad 3.

[0061] 8(b), when the pad heater 11 is rotated from the initial position (see FIG. 3(c)) in which the long portion 11a of the pad heater 11 extends substantially parallel to the longitudinal direction of the polishing pad 3, the direction and amount of superheated steam colliding with the polishing surface of the polishing pad 3 changes. As a result, the pad surface temperature can be adjusted by controlling the rotation angle of the pad heater 11 from the initial position.

[0062] Figure 9(a) is a schematic diagram showing an example of a rotation mechanism 95 for rotating the pad heater 11 around its longitudinal axis, Figure 9(b) is a cross-sectional view showing the pad heater 11 shown in Figure 9(a) when rotated upward, and Figure 9(c) is a cross-sectional view showing the pad heater 11 shown in Figure 9(a) when rotated downward.

[0063] 9(a) is attached to the end of the pad heater 11 and is composed of a rotation actuator 96 that rotates the pad heater 11. The rotation actuator 96 is, for example, a servo motor or a stepping motor.

[0064] The rotation mechanism 95 is connected to the control device 40. The control device 40 controls the operation of the rotation mechanism 95 (i.e., the amount of operation of the rotation actuator 96) based on the measurement value of the pad temperature measuring device 10, thereby changing the direction of the injection port 11b of the pad heater 11 relative to the polishing surface of the polishing pad 3 (see arrow B in FIG. 3(b)).

[0065] As shown in FIG. 9(b) and FIG. 9(c), when the direction of the nozzle 11b of the pad heater 11 relative to the polishing surface of the polishing pad 3 is changed, the amount and temperature of the superheated steam colliding with the polishing surface of the polishing pad 3 changes. As shown in FIG. 9(b), when the pad heater 11 is rotated in the upward direction, the amount and temperature of the superheated steam colliding with the polishing surface of the polishing pad 3 decreases, and the pad surface temperature can be lowered. As shown in FIG. 9(c), when the pad heater 11 is rotated in the downward direction, the amount and temperature of the superheated steam colliding with the polishing surface of the polishing pad 3 increases, and the pad surface temperature can be increased. Therefore, the pad surface temperature can be adjusted by controlling the rotation angle of the pad heater 11 relative to the support arm 86.

[0066] The pad temperature adjustment device 5 may have a combination of any two of the above-mentioned up-down movement mechanism 85, pivot mechanism 90, and rotation mechanism 90, or may have all of the up-down movement mechanism 85, pivot mechanism 90, and rotation mechanism 90.

[0067] FIG. 10 is a cross-sectional view showing a pad heater according to another embodiment. The pad heater 11 shown in FIG. 10 further includes a shutter mechanism 76 including a shutter 77 for opening and closing the injection port 11b and an actuator 78 for driving the shutter 77. In the example shown in FIG. 10, the shutter mechanism 76 has two shutters 77, but may have only one shutter 77. The actuator 78 may be, for example, a piston cylinder device having a piston for moving the shutter 77, or may be a motor (for example, a servo motor or a stepping motor) for moving the shutter 77. In one embodiment, the actuator 78 may be a piezo actuator that moves the shutter 77 by utilizing the piezoelectric effect of a piezo element.

[0068] The actuator 78 is connected to the control device 40. The control device 40 controls the operation of the actuator 78 (i.e., the amount of operation of the actuator 78) based on the measurement value of the pad temperature measuring device 10, thereby controlling the opening degree of the jet orifice 11b. In this embodiment, the opening degree of the jet orifice 11b corresponds to the width of the jet orifice 11b in a direction perpendicular to the longitudinal direction. Changing the opening degree of the jet orifice 11b changes the flow rate and temperature of the superheated steam colliding with the polishing surface of the polishing pad 3, and changes the pad surface temperature. Therefore, by controlling the opening degree of the jet orifice 11b, the pad surface temperature can be adjusted.

[0069] Fig. 11(a) and Fig. 11(b) are diagrams showing a shutter mechanism according to another embodiment. More specifically, Fig. 11(a) is a perspective view of the shutter mechanism according to another embodiment seen from the bottom side, and Fig. 11(b) is a diagram showing an example of the operation of the shutter mechanism shown in Fig. 11(a). The configuration of this embodiment that is not particularly described is similar to the embodiment described with reference to Fig. 10, so that the overlapping description will be omitted.

[0070] The shutter mechanism 76 shown in FIG. 11(a) has a shutter 77 composed of a plurality of piezoelectric elements 101. The plurality of piezoelectric elements 101 are arranged along the longitudinal direction of the ejection port 11b (i.e., along the longitudinal direction of the long portion 11a). In this embodiment, the long portion 11a of the pad heater 11 has a rectangular cross section, but as described above, the cross-sectional shape of the long portion 11a is not limited to this example. The shutter 77 shown in FIG. 11(a) adjusts the opening of the ejection port 11b of the pad heater 11 by an expansion and contraction action due to the inverse piezoelectric effect of the piezoelectric elements.

[0071] Each piezoelectric element 101 is connected to a piezoelectric element driver 103, which is connected to a control device 40. In FIG. 11(a), in order to prevent the diagram from becoming too complicated, only control lines extending from some of the piezoelectric elements 101 to the piezoelectric element driver 103 are drawn. The control device 40 can independently control the expansion and contraction operations of each piezoelectric element 101 by controlling the operation of the piezoelectric element driver 103 (see, for example, FIG. 11(b)). The piezoelectric element driver 103 functions as an actuator that adjusts the opening degree of the ejection port 11b of the pad heater 11.

[0072] When the pad temperature measuring device 10 is the above-mentioned temperature distribution measuring device, the control device 40 can obtain the temperature distribution (temperature profile) of the polishing pad 3 along the radial direction of the polishing pad 3. Fig. 12 is a graph showing an example of a target temperature profile of the polishing pad and a temperature profile obtained by the pad temperature measuring device. In Fig. 12, the vertical axis represents the pad surface temperature, and the horizontal axis represents the radial position of the polishing pad.

[0073] In order to precisely control the in-plane uniformity (flatness) of the entire surface of the wafer W after polishing, it is preferable to always make the temperature profile coincide with the target temperature. Therefore, in this embodiment, the control device 40 controls the expansion and contraction operation of each piezoelectric element 101 so that the temperature profile acquired by the pad temperature measuring device 10 coincides with the target temperature. For example, as shown in FIG. 12, the control device 40 greatly contracts the piezoelectric element 101 corresponding to the position Pa of the polishing pad 3 where the difference Da between the target temperature and the measured temperature is large, thereby increasing the injection amount of superheated steam. On the other hand, the control device 40 reduces the expansion and contraction amount of the piezoelectric element 101 corresponding to the position Pb of the polishing pad 3 where the difference Db between the target temperature and the measured temperature is small, thereby reducing the injection amount of superheated steam to be less than the injection amount at the position Pa.

[0074] The control device 40 controls the operation of the piezoelectric element driver 103 (i.e., the amount of expansion and contraction of each piezoelectric element 101) based on the measurement value of the pad temperature measuring device 10, thereby freely controlling the opening of the jet orifice 11b along the radial direction of the polishing pad 3. As described above, changing the opening of the jet orifice 11b changes the flow rate and temperature of the superheated steam colliding with the polishing surface of the polishing pad 3, and changes the pad surface temperature. By performing such pad temperature control, the temperature profile of the entire polishing pad 3 can be made to coincide with the target temperature. As a result, the wafer W can be precisely polished.

[0075] FIG. 13 is a cross-sectional view that shows a schematic diagram of a pad heater 11 according to yet another embodiment. FIG. 13 shows a cross-section of the long portion 11a of the pad heater 11. The pad heater 11 shown in FIG. 13 has a heater 79 arranged inside the long portion 11a. The heater 79 is also connected to the control device 40, and the control device 40 controls the operation (e.g., ON / OFF operation) of the heater 79. The heater 79 can reheat the superheated steam that has cooled while flowing from the superheated steam generator 31 to the pad heater 11. Reheating the superheated steam prevents problems such as condensation of the superheated steam in the pad heater 11.

[0076] Fig. 14 is a schematic diagram showing a polishing apparatus equipped with a pad temperature adjustment device according to still another embodiment. Fig. 14 corresponds to a top view of the polishing apparatus. The configuration of this embodiment that is not particularly described is similar to the above-mentioned embodiment, so that the duplicated description will be omitted.

[0077] 14, components such as the polishing table 2, polishing pad 3, and polishing head 1 are disposed in a polishing chamber PR, and polishing of the wafer W is performed in the polishing chamber PR. The polishing chamber PR is a space partitioned by four partitions 58, and the pressure inside the polishing chamber PR is kept at a predetermined pressure (e.g., a pressure lower than that outside the polishing chamber PR). Note that three of the four partitions 58 are depicted in FIG. 14.

[0078] When the pad heater 11 injects superheated steam and the pad cooler 51 injects cooling gas, the pressure in the polishing chamber PR may rise above a predetermined pressure and exceed a tolerance value set for the set pressure of the polishing chamber PR. For this reason, in this embodiment, the pad temperature adjustment device 5 is provided with a polishing chamber suction device 66 that sucks air from the polishing chamber PR so that the pressure in the polishing chamber PR is maintained at a predetermined value. The polishing chamber suction device 66 shown in FIG. 14 is provided with a vacuum device 67 such as a vacuum pump or a suction pump, a polishing chamber suction line 68 extending from the polishing chamber PR, and a damper 69 arranged in the polishing chamber suction line 68.

[0079] The control device 40 is connected to the damper 69, and adjusts the opening of the damper 69 so that the pressure in the polishing chamber PR is maintained at a predetermined value. For example, the control device 40 adjusts the opening of the damper 69 so that the flow rate of air flowing through the polishing chamber suction line 68 is equal to the sum of the measurements of the flow regulators 35 and 54. In one embodiment, the control device 40 is also connected to the vacuum device 67, and may control the opening of the damper 69 and / or the operation of the vacuum device 67 so that the pressure in the polishing chamber PR is maintained at a predetermined value.

[0080] Fig. 15(a) is a schematic diagram showing a pad cooler of a cooling mechanism according to another embodiment, and Fig. 15(b) is a cross-sectional view of the pad cooler shown in Fig. 15(a). The configuration of this embodiment that is not particularly described is similar to the embodiment shown in Fig. 4(a) and Fig. 4(b), and therefore the duplicated description will be omitted.

[0081] The pad cooler 51 shown in FIG. 15(a) and FIG. 15(b) further includes a shutter mechanism 110 including a shutter 111 for opening and closing the jet orifice 51b, and an actuator 113 for driving the shutter 111. In the example shown in FIG. 15, the long portion 51a of the pad cooler 51 has a rectangular cross section, and the shutter mechanism 110 has a pair of shutters 111 capable of adjusting the opening degree of all the jet orifices 51b. In one embodiment, the shutter mechanism 110 may have only one shutter 111 capable of adjusting the opening degree of all the jet orifices 51b. The actuator 113 may be, for example, a piston cylinder device having a piston for moving the shutter 111, or may be a motor (for example, a servo motor or a stepping motor) for moving the shutter 111. In one embodiment, the actuator 113 may be a piezoelectric actuator for moving the shutter 111 by utilizing the inverse piezoelectric effect of a piezoelectric element.

[0082] The actuator 113 is connected to the control device 40. The control device 40 controls the operation of the actuator 78 of the pad heater 11 or the operation of the piezoelectric element driver 103 and the operation of the actuator 113 (i.e., the operation amount of the nozzle 51b) based on the measured value of the pad temperature measuring device 10, thereby controlling the aperture of the nozzle 11b and the nozzle 51b. In this embodiment, the aperture of the nozzle 51b corresponds to the width of the nozzle 51b in a direction perpendicular to the longitudinal direction. When the aperture of the nozzle 11b and the nozzle 51b is changed, the flow rate and temperature of the superheated steam colliding with the polishing surface of the polishing pad 3 and the flow rate and temperature of the cooling gas change, and the pad surface temperature changes. Therefore, the pad surface temperature can be precisely adjusted by controlling the aperture of the nozzle 11b and the nozzle 51b.

[0083] FIG. 16 is a cross-sectional view showing a pad cooler of a cooling mechanism according to yet another embodiment. As shown in FIG. 16, the pad cooler 51 may have a guide plate 120 attached to the lower part of the pad cooler 51. Specifically, the guide plate 120 is attached to the lower part of the long part 51a. The guide plate 120 may be a single plate extending over the entire long part 51a, or may be a plurality of plates attached corresponding to each injection port 51b. The guide plate 120 has a shaft 120a at its end, and the shaft 120a is rotatably attached to a bearing 121 fixed to the lower surface of the long part 51a. The cooling mechanism 50 further has a rotation actuator 122 that rotates the guide plate 120 around the shaft 120a, and the rotation actuator 122 is connected to the control device 40.

[0084] Rotating guide plate 120 changes the position and amount of cooling gas that collides with the polishing surface of polishing pad 3. As a result, the pad surface temperature can be adjusted by controlling the rotation angle of guide plate 120 as well.

[0085] When the pad cooler 51 has a plurality of guide plates 120 attached corresponding to each of the jet ports 51b, the pad temperature measuring device 10 is preferably a temperature distribution measuring device capable of acquiring the temperature distribution (temperature profile) of the polishing pad 3 along the radial direction of the polishing pad 3. The control device 40 can independently control the rotation angle of each guide plate 120 based on the temperature profile acquired by the pad temperature measuring device 10. That is, the control device 40 can independently control the rotation angle of each guide plate 120 so that the temperature profile of the entire polishing pad 3 coincides with the target temperature. As a result, the wafer W can be precisely polished.

[0086] Fig. 17 is a schematic diagram showing a pad cooler of a cooling mechanism according to still another embodiment. As shown in Fig. 17, the pad temperature adjustment device 5 may have a rotation mechanism 130 that rotates the pad cooler 51 around its longitudinal axis.

[0087] 17 is configured by a rotation actuator 131 that is attached to an end of the pad cooler 51 and rotates the pad cooler 51. The rotation actuator 131 is, for example, a servo motor or a stepping motor.

[0088] The rotation mechanism 130 is connected to the control device 40. The control device 40 controls the operation of the rotation mechanism 130 (i.e., the amount of operation of the rotation actuator 131) based on the measurement value of the pad temperature measuring device 10, thereby changing the orientation of the jet nozzle 51b of the pad cooler 51 with respect to the polishing surface of the polishing pad 3. Changing the orientation of the jet nozzle 51b of the pad cooler 51 with respect to the polishing surface of the polishing pad 3 changes the amount and temperature of the cooling gas that collides with the polishing surface of the polishing pad 3. Therefore, by controlling the rotation angle of the pad cooler 51 with respect to the polishing surface of the polishing pad 3, the pad surface temperature can be adjusted.

[0089] In the pad temperature adjustment device 5 according to the embodiment described above, the control device 40 controls at least one of the temperature, flow rate, injection amount, injection position, and injection range of the superheated steam and the cooling gas based on the measured value of the pad temperature measurement device 10, thereby controlling the temperature of the polishing surface of the polishing pad 3. More specifically, the control device 40 controls at least one of the operations of the flow rate regulator 35, 54, the superheated steam generator 31, the vertical movement mechanism 85, the rotation mechanism 90, the rotation mechanism 95, 130, the shutter mechanism 77, 110, the heater 79, the mixing valve 81, and the guide plate 120 based on the measured value of the pad temperature measurement device 10, thereby making the temperature of the polishing surface of the polishing pad 3 reach a target temperature and maintaining it at the target temperature. This allows the wafer W to be precisely polished to a desired film thickness. In particular, in an embodiment in which the shutter 77 is composed of a plurality of piezoelectric elements 10, and an embodiment in which the pad cooler 51 has a plurality of guide plates 120 attached corresponding to each injection port 51b, the temperature profile of the entire polishing pad 3 can be made to match the target temperature.

[0090] In one embodiment, the control device 40 may control the pad surface temperature by adjusting the flow rate and / or temperature of the cooling gas while supplying superheated steam adjusted to a predetermined temperature from the pad heater 11 to the polishing pad 3 at a constant flow rate.

[0091] In one embodiment, the control device 40 may temporarily increase the flow rate and / or temperature of the superheated steam when starting to control the surface temperature of the polishing pad 3. More specifically, the control device 40 supplies, to the pad heater 11, superheated steam having a flow rate and / or temperature greater than the flow rate and / or temperature of the superheated steam calculated to make the surface temperature of the polishing pad 3 reach the target temperature.

[0092] In this specification, the control operation of temporarily increasing the flow rate and / or temperature of the superheated steam when starting control of the surface temperature of the polishing pad 3 is referred to as a "pad temperature control start operation." Furthermore, in this specification, the flow rate and temperature of the superheated steam calculated to make the surface temperature of the polishing pad 3 reach a target temperature are referred to as the "set flow rate" and the "set temperature," respectively.

[0093] In the pad temperature adjustment start operation, the control device 40, for example, controls the operation of the flow rate adjuster 35 to increase the flow rate of the superheated steam ejected from the nozzle 11a of the pad heater 11 to a value higher than the set flow rate. Alternatively, in the pad temperature adjustment start operation, the control device 40 may control the operation of the superheated steam generator 31 and / or the heater 79 to increase the temperature of the superheated steam ejected from the nozzle 11a of the pad heater 11 to a value higher than the set temperature. The control device 40 may control the operation of the flow rate adjuster 35 and the operation of the superheated steam generator 31 and / or the heater 79 to increase the flow rate and temperature of the superheated steam ejected from the nozzle 11a of the pad heater 11 to values ​​higher than the set flow rate and set temperature. These operations allow the pad surface temperature to quickly reach the target temperature.

[0094] FIG. 18 is a graph for explaining an example of the pad temperature adjustment start operation. In the graph shown in FIG. 18, the vertical axis represents the pad surface temperature, and the horizontal axis represents time. In FIG. 18, the target temperature is depicted by a horizontal solid line, and the change in pad surface temperature when the pad temperature adjustment start operation is performed is depicted by a dashed line. In FIG. 18, the curve drawn by a two-dot dashed line represents the change in pad surface temperature when the pad temperature adjustment start operation is not performed. Point Ts in FIG. 18 represents the time point when the pad temperature adjustment device 5 starts temperature adjustment of the polishing pad 3.

[0095] As described above, in the pad temperature control start operation, the flow rate and / or temperature of the superheated steam is temporarily increased above the set flow rate and / or set temperature. In the graph shown in FIG. 18, the flow rate of the superheated steam is increased above the set flow rate. In the following, the pad temperature control start operation in which superheated steam is ejected at a flow rate greater than the set flow rate will be described. The pad temperature control start operation in which superheated steam is ejected at a temperature greater than the set temperature can also be performed by a similar control operation.

[0096] As shown in Fig. 18, the control device 40 prestores a set time Ta that determines the longest execution time of the pad temperature adjustment start operation. The above-mentioned set flow rate and set time Ta can be determined arbitrarily. For example, the set time Ta may be obtained from an experiment in which a predetermined flow rate of superheated steam is sprayed from the nozzle 11a of the pad heater 11 onto the polishing surface of the polishing pad 3 without executing the pad temperature adjustment start operation. In this experiment, the time from the start of temperature adjustment of the polishing pad 3 until the pad surface temperature reaches the target temperature is measured, and the measured time is determined as the set time Ta.

[0097] The control device 40 calculates the flow rate of superheated steam for causing the pad surface temperature to reach the target temperature between the start of temperature adjustment of the polishing pad 3 (i.e., time Ts) and the arrival of the set time Ta. To execute the pad temperature adjustment start operation, the control device 40 injects superheated steam from the injection port 11a of the pad heater 11 at a flow rate greater than the calculated flow rate of superheated steam. This allows the pad surface temperature to reach the target temperature more quickly, and therefore allows the polishing conditions for the wafer W to reach the optimal conditions more quickly.

[0098] During the pad temperature adjustment start operation, the control device 40 stops the operation of the cooling mechanism 50 and the suction mechanism 60. When the pad surface temperature reaches the target temperature (see time Tb in FIG. 18), the control device 40 ends the pad temperature adjustment start operation and starts normal pad temperature adjustment control for maintaining the pad surface temperature at the target temperature. More specifically, the control device 40 starts the operation of the cooling mechanism 50 and the suction mechanism 60, and starts normal control for controlling at least one of the temperature, flow rate, injection amount, injection position, and injection range of the above-mentioned superheated steam and cooling gas. This makes it possible to minimize overshoot, which is a phenomenon in which the pad surface temperature exceeds the target temperature.

[0099] Even if the pad surface temperature does not reach the target temperature and the elapsed time of the pad temperature adjustment start operation measured from time Ts reaches the set time Ta, the control device 40 starts normal control to control at least one of the temperature, flow rate, injection amount, injection position, and injection range of the superheated steam and the cooling gas. In one embodiment, the control device 40 may determine that an abnormality has occurred in the pad temperature adjustment device 5 and stop the polishing process of the wafer W.

[0100] 19 is a schematic diagram showing a polishing apparatus equipped with a pad temperature adjustment device according to still another embodiment. The configuration of this embodiment that is not specifically described is similar to the above-described embodiment, and therefore the duplicated description will be omitted.

[0101] The pad temperature adjusting device 5 shown in Fig. 19 includes a cleaning device 45 that cleans the pad heater 11, pad cooler 51, and suction nozzle 61 at a retracted position to the side of the polishing pad 3. The control device 40 is connected to the cleaning device 45 and controls the operation of the cleaning device 45. Note that Fig. 19 illustrates only the pad heater 11, pad cooler 51, suction nozzle 61, and cleaning device 45 of the pad temperature adjusting device 5, and the illustration of the other components is omitted.

[0102] In this embodiment, the pad temperature adjustment device 5 is equipped with the above-mentioned rotation mechanism 90, and the control device 40 operates the rotation actuator 92 (see Figure 8(a)) of the rotation mechanism 90 to move the pad heater 11, the pad cooler 51, and the suction nozzle 61 from the initial position shown in Figure 3(c) to the retracted position shown in Figure 19.

[0103] The cleaning device 45 includes a plurality of sprays 46 that spray cleaning liquid (e.g., pure water) from above and below onto the pad heater 11, pad cooler 51, and suction nozzle 61 that have been moved to the waiting position. After the pad heater 11, pad cooler 51, and suction nozzle 61 have been moved to the waiting position, the control device 40 injects cleaning liquid from the sprays 46 onto the pad heater 11, pad cooler 51, and suction nozzle 61. By this operation, dirt adhering to the pad heater 11, pad cooler 51, and suction nozzle 61 is washed away.

[0104] When the cleaning of the pad heater 11, the pad cooler 51, and the suction nozzle 61 is completed, the control device 40 controls the operation of the rotating mechanism 90 to move the pad heater 11, the pad cooler 51, and the suction nozzle 61 to their initial positions (see FIG. 3(c)). If droplets of cleaning liquid fall onto the polishing pad 3 from the pad heater 11, the pad cooler 51, and the suction nozzle 61 that have been moved to their initial positions, the concentration of the polishing liquid (slurry) may change, which may adversely affect the polishing performance. Therefore, in this embodiment, the cleaning device 45 may have multiple nozzles 47 that blow gas (e.g., air, nitrogen, or argon) onto the pad heater 11, the pad cooler 51, and the suction nozzle 61 after cleaning with the cleaning liquid.

[0105] The gas sprayed from the nozzle 47 blows off the cleaning liquid adhering to the pad heater 11, the pad cooler 51, and the suction nozzle 61, and can dry the pad heater 11, the pad cooler 51, and the suction nozzle 61. This drying process can prevent droplets of the cleaning liquid from dropping onto the polishing pad 3 from the pad heater 11, the pad cooler 51, and the suction nozzle 61 that have been moved to their initial positions. In one embodiment, the spray 46 may have a function of spraying gas onto the pad heater 11, the pad cooler 51, and the suction nozzle 61 in addition to the cleaning liquid.

[0106] In the above-described embodiment, the pad temperature adjusting device 5 includes not only the pad heater 11 but also the cooling mechanism 50 and the suction mechanism 60. However, the pad temperature adjusting device 5 may omit either or both of the pad cooler 51 and the suction nozzle 61. When either or both of the pad cooler 51 and the suction nozzle 61 are omitted, it is preferable that the pad temperature adjusting device 5 has at least one of the above-described vertical movement mechanism 85, the rotation mechanism 90, and the rotation mechanism 95. These mechanisms 85, 90, and 95 enable fine adjustment of the pad surface temperature.

[0107] Fig. 20 is a schematic diagram showing a heating fluid supply system and a cooling fluid supply system according to another embodiment. The configuration of this embodiment that is not specifically described is similar to the configuration of the embodiment shown in Fig. 2, so duplicated descriptions will be omitted.

[0108] The heating fluid supply system 30 shown in Fig. 20 includes a thermometer 71 disposed in the superheated steam supply line 32, and a flow meter 72 and a flow regulator 73 (e.g., a flow control valve) disposed in the gas supply line 34. The thermometer 71 is connected to the control device 40 and transmits a measurement value of the temperature of the superheated steam to the control device 40. The flow meter 72 and the flow regulator 73 are also connected to the control device 40. The flow meter 72 transmits a measurement value of the flow rate of the gas flowing through the gas supply line 34 to the control device 40, and the control device 40 controls the operation of the flow regulator 73.

[0109] In this embodiment, the control device 40 calculates the temperature of the steam heated by the superheated steam generator 31 based on the pad surface temperature measured by the pad temperature measuring device 10. The control device 40 controls the operation of the superheated steam generator 31 so that the temperature of the superheated steam flowing through the superheated steam supply line 32 coincides with the calculated steam temperature.

[0110] In addition to or instead of controlling the operation of the superheated steam generator 31, the control device 40 may control the operation of the flow regulator 73 based on the pad surface temperature measured by the pad temperature measuring device 10. In this case, the control device 40 calculates the temperature of the steam heated by the superheated steam generator 31 and / or the flow rate of the gas flowing through the gas supply line 34. The control device 40 controls the operation of the superheated steam generator 31 and / or the operation of the flow regulator 73 so that the temperature of the superheated steam flowing through the superheated steam supply line 32 matches the calculated steam temperature and / or so that the flow rate of the gas flowing through the gas supply line 34 matches the calculated gas flow rate.

[0111] Fig. 21 is a schematic diagram showing a heated fluid supply system according to still another embodiment. The configuration of this embodiment that is not specifically described is similar to the heated fluid supply system of the embodiment shown in Fig. 2, so duplicated descriptions will be omitted.

[0112] 21 has a drain tank 37 to which an exhaust line 36 is connected. A water branch line 38 branched off from the water supply line 33 is also connected to the drain tank 37, and a valve 39 is disposed on the water branch line 38. When the valve 39 is opened, room temperature water is supplied to the drain tank 37.

[0113] The excess superheated steam that has flowed through the exhaust line 36 is supplied to the drain tank 37, where it condenses and returns to water. In order to efficiently condense the excess superheated steam, room temperature water is supplied to the drain tank 37 through a water branch line 38, thereby lowering the atmospheric temperature within the drain tank 37. A drain line 83 is connected to the bottom of the drain tank 37, and the condensed water from the superheated steam is discharged from the polishing apparatus through the drain line 83.

[0114] Although not shown, the water branch line 38 may be omitted and the drain line 83 may be connected to the superheated steam generator 31. In this case, the high-temperature water stored in the drain tank 37 is supplied to the superheated steam generator 31 and used again to generate superheated steam. With this configuration, energy-saving operation of the superheated steam generator 31 can be expected.

[0115] Fig. 22 is a schematic diagram showing a combination of a cooling fluid supply system 50 and a suction mechanism 60 according to another embodiment. The vacuum source 63 of the suction mechanism 60 shown in Fig. 22 is an ejector. A gas branch line 55 branched from the cooling gas supply line 53 of the cooling fluid supply system 52 is connected to the vacuum source 63, and the driving fluid of the vacuum source 63 is a room temperature gas supplied to the vacuum source 63 through the gas branch line 55. A flow rate regulator 74 (e.g., a flow rate control valve) that regulates the flow rate of the driving fluid is disposed in the gas branch line 55. With such a configuration, the running cost of the vacuum source 63 can be reduced.

[0116] Fig. 23 is a schematic diagram showing a combination of a heating fluid supply system 30, a cooling fluid supply system 50, and a suction mechanism 60 according to another embodiment. Since the embodiments not specifically described are similar to the embodiments described with reference to Figs. 21 and 22, the duplicated description will be omitted.

[0117] 23, a gas branch line 56 different from a gas branch line 55 for supplying a driving fluid to a vacuum source 63 which is an ejector is branched off from a cooling gas supply line 53. In the following description, the gas branch line 55 is referred to as a first branch line 55, and the gas branch line 56 is referred to as a second branch line 56.

[0118] The second branch line 56 is connected to the exhaust line 36. The room temperature gas that has flowed through the second branch line 56 to the exhaust line 36 is mixed with excess superheated steam in the exhaust line 36 and cools the superheated steam. Therefore, the cooled superheated steam and water condensed from the superheated steam are supplied to the drain tank 37.

[0119] A gas discharge line 41 is connected to the waste liquid tank 37, and the gas discharge line 41 is connected to an exhaust line 65 of a vacuum source 63 which is an ejector. The gas that has flowed from the exhaust line 36 to the waste liquid tank 37 flows through the gas discharge line 41 into the exhaust line 65, and is exhausted from the polishing apparatus via the exhaust line 65.

[0120] The above-described embodiments have been described for the purpose of enabling a person having ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope according to the technical idea defined by the claims. [Explanation of symbols]

[0121] 1 Polishing head 2 Polishing table 3 Polishing Pads 9 Heating mechanism 10 Pad temperature measuring device 11 Pad heating machine 30 Heated Fluid Supply System 31 Superheated steam generator 32 Superheated steam supply line 35 Flow regulator 40 Control device 50 Cooling mechanism 51 Pad Cooler 52 Cooling Fluid Supply System 53 Cooling gas supply line 54 Flow regulator 60 Suction mechanism 61 Suction nozzle 62 Suction Line 63 Vacuum source (vacuum device) 64 Flow regulator

Claims

1. a polishing table for supporting the polishing pad; a polishing head that presses a substrate against a polishing surface of the polishing pad to polish the substrate; a pad temperature measuring device for measuring the temperature of the polishing surface; a pad temperature adjustment device for adjusting the temperature of the polishing surface; a control device for controlling an operation of the pad temperature adjustment device based on the temperature of the polishing surface measured by the pad temperature measurement device; the pad temperature adjustment device includes a pad heater disposed above and spaced apart from the polishing surface; the pad heater has a long portion extending in a substantially radial direction of the polishing pad, and a slit-shaped injection port formed along the longitudinal direction of the long portion for injecting a heated fluid toward the polishing surface, The pad temperature adjustment device further includes a shutter mechanism for adjusting an opening degree of the injection port, the pad temperature measuring device is a measuring device capable of measuring a temperature profile along a radial direction of the polishing pad, A polishing apparatus, wherein the shutter mechanism is composed of piezoelectric elements arranged along the longitudinal direction of the nozzle of the pad heater.

2. 2. The polishing apparatus according to claim 1, wherein said pad temperature adjustment device further comprises a vertical movement mechanism for moving said pad heater up and down relative to said polishing surface.

3. 3. The polishing apparatus according to claim 1, wherein the pad temperature adjusting device further comprises a rotating mechanism for rotating the pad heater in a horizontal direction relative to the polishing surface.

4. 4. The polishing apparatus according to claim 1, wherein the pad temperature adjustment device further comprises a rotation mechanism for rotating the pad heater about its longitudinal axis.

5. 2. The polishing apparatus according to claim 1, wherein the control device adjusts the amount of expansion and contraction of each piezoelectric element based on the temperature profile.

6. 6. The polishing apparatus according to claim 1, wherein the pad temperature adjustment device further comprises a cooling mechanism that injects a cooling fluid onto the polishing surface to cool the polishing surface.

7. the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface; 7. The polishing apparatus of claim 6, wherein the pad temperature conditioning device further comprises a rotation mechanism for rotating the pad cooler about its longitudinal axis.

8. the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface; the pad cooler has a long portion extending in a substantially radial direction of the polishing pad, and a plurality of injection ports arranged along a longitudinal direction of the long portion for injecting the cooling fluid toward the polishing surface, 8. The polishing apparatus according to claim 6, wherein said cooling mechanism further comprises a shutter mechanism for adjusting opening degrees of a plurality of nozzles of said pad cooler.

9. the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface; The cooling mechanism includes a guide plate attached to the pad cooler; 9. The polishing apparatus according to claim 6, further comprising an actuator that rotates the guide plate.

10. 10. The polishing apparatus according to claim 1, wherein the pad temperature adjustment device further comprises a suction mechanism arranged above the polishing surface and configured to suck in air above the polishing surface.

11. The polishing apparatus according to claim 1 , wherein the pad temperature adjustment device further comprises a heater disposed within the pad heater.

12. The polishing table is disposed in a polishing chamber, 12. The polishing apparatus according to claim 1, wherein the pad temperature adjusting device further comprises a polishing chamber suction device that sucks air from within the polishing chamber so that the pressure in the polishing chamber is maintained at a predetermined value.

13. 13. The polishing apparatus according to claim 1, further comprising a cleaning device that cleans the pad heater at a retreated position to the side of the polishing pad.

14. 14. The polishing apparatus according to claim 1, wherein the heating fluid is superheated steam.

15. The control device executes a pad temperature control start operation when starting control of the surface temperature of the polishing pad; A polishing apparatus as described in any one of claims 1 to 14, wherein the pad temperature control start operation is an operation of supplying the heating fluid to the pad heater having a flow rate and / or temperature greater than the flow rate and / or temperature of the heating fluid calculated to cause the temperature of the polishing surface to reach a target temperature.

16. The pad temperature adjustment device is a heating fluid supply line for supplying the heating fluid to the pad heater; a flow regulator disposed in the heating fluid supply line; 16. The polishing apparatus according to claim 15, wherein the control device increases the flow rate of the heating fluid using the flow regulator during the pad temperature adjustment start operation.

17. 17. The polishing apparatus according to claim 15, wherein the control device terminates the pad temperature adjustment start operation when the temperature of the polishing surface of the polishing pad reaches the target temperature.

18. A polishing method for polishing a substrate by pressing the substrate against a polishing surface of a polishing pad while adjusting a temperature of the polishing surface of the polishing pad by a pad heater disposed above and spaced apart from the polishing surface, comprising: When starting the control of the temperature of the polishing surface, a pad temperature control start operation is performed to make the temperature of the polishing surface reach a target temperature; During polishing of the substrate, a heating fluid is sprayed from a slit-shaped spray port formed in a long portion of the pad heater based on a temperature of the polishing surface measured by a pad temperature measuring device that measures a temperature of the polishing surface, thereby maintaining the temperature of the polishing surface at the target temperature; the pad temperature control start operation is an operation of supplying the heating fluid to the pad heater, the heating fluid having a flow rate and / or a temperature greater than a flow rate and / or a temperature of the heating fluid calculated for making the temperature of the polishing surface reach a target temperature, maintaining the temperature of the polishing surface at the target temperature by at least one of adjusting a temperature and / or a flow rate of the heating fluid, adjusting a vertical movement of the pad heater relative to the polishing surface, adjusting a horizontal rotational movement of the pad heater relative to the polishing surface, and adjusting a rotational movement of the pad heater about its longitudinal axis; The flow rate of the heating fluid is adjusted by a shutter capable of adjusting the opening of the nozzle of the pad heater, the pad temperature measuring device is a measuring device capable of measuring a temperature profile along a radial direction of the polishing pad, the shutter is composed of piezoelectric elements arranged along the longitudinal direction of the nozzle of the pad heater, The flow rate of the heating fluid is adjusted by adjusting the amount of expansion and contraction of each piezoelectric element based on the temperature profile.

19. 20. The polishing method according to claim 18, wherein the step of maintaining the temperature of the polishing surface at the target temperature is performed by the pad heater and a cooling mechanism that sprays a cooling fluid onto the polishing surface to cool the polishing surface.

20. the cooling mechanism includes a pad cooler positioned above and spaced apart from the polishing surface; the pad cooler has a long portion extending in a substantially radial direction of the polishing pad, and a plurality of injection ports arranged along a longitudinal direction of the long portion for injecting the cooling fluid toward the polishing surface, The polishing method according to claim 19, wherein the step of maintaining the temperature of the polishing surface at the target temperature is further performed by adjusting at least one of the following: a rotational motion of rotating the pad cooler around its longitudinal axis, adjusting the opening degree of a plurality of jets of the pad cooler by a shutter, and adjusting the pivoting motion of a guide plate attached to the pad cooler.

21. 21. The polishing method according to claim 18, wherein the pad temperature adjustment start operation is an operation of increasing the flow rate of the heating fluid using a flow regulator arranged in a heating fluid supply line that supplies the heating fluid to the pad heater.

22. 22. The polishing method according to claim 18, wherein the pad temperature adjustment starting operation is terminated when the temperature of the polishing surface of the polishing pad reaches the target temperature.

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