Polishing apparatus and polishing method

Abstract

This invention provides a polishing apparatus and polishing method that can polish a substrate with the required polishing performance without causing scratches or other defects and contamination. The polishing apparatus includes: a polishing table (2) for supporting a polishing pad (3); a polishing head (1) for pressing a substrate (W) against the polishing surface of the polishing pad (3) to polish the substrate (W); a pad temperature measuring device (10) for measuring the temperature of the polishing surface; a pad temperature adjusting device (5) for adjusting the temperature of the polishing surface; and a control device (40) for controlling the operation of the pad temperature adjusting device (5) based on the temperature of the polishing surface measured by the pad temperature measuring device (10). The pad temperature adjusting device (5) includes: a pad heater (11) disposed away from the polishing surface upwards, the pad heater (11) having: an elongated portion (11a) extending in a generally radial direction along the polishing pad (3); and a slit-shaped nozzle (11b) formed along the long side of the elongated portion (11a) for spraying a heating fluid onto the polishing surface.

Description

Technical Field

[0001] This invention relates to a polishing apparatus and polishing method, which allows a substrate such as a semiconductor wafer to slide on a polishing pad and be polished. In particular, it relates to a polishing apparatus and polishing method that polishes a substrate while adjusting the surface temperature of the polishing pad. Prior Technology

[0002] Chemical mechanical polishing (CMP) equipment is used in the manufacture of semiconductor devices to polish the surface of substrates. A CMP equipment uses a polishing head to hold and rotate the substrate, pressing it against a polishing pad on a rotating polishing table to polish the substrate surface. During polishing, an polishing slurry (paste) is supplied to the polishing pad, and the substrate surface is planarized due to the chemical action of the slurry and the mechanical action of the abrasive particles contained in the slurry.

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

[0004] Therefore, a pad temperature adjustment device has been used to adjust the surface temperature of the polishing pad (see, for example, Patent Documents 1 and 2). The pad temperature adjustment device has a pad contact member (or heat exchanger) that contacts the surface of the polishing pad and supplies a temperature-adjusted heating liquid and a cooling liquid. By adjusting the flow rate of the heating liquid and the flow rate of the cooling liquid supplied to the pad contact member, the surface temperature of the polishing pad during substrate polishing can be maintained at the desired temperature. [Existing Technical Documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2012-176449 [Patent Document 2] Japanese Patent Application Publication No. 2017-148933 Summary of the Invention

[0006] [The problem the invention aims to solve] However, the pad contact components of the pad temperature adjustment device inevitably come into contact with the polishing slurry during substrate polishing. Consequently, contaminants such as abrasive particles from the polishing slurry and abrasive powder from the polishing pad adhere to the pad contact components. If these contaminants detach from the pad contact components during substrate polishing, they can contaminate the substrate or cause defects such as scratches. Furthermore, contaminants detached from the pad contact components may deteriorate the surface condition of the polishing pad, potentially adversely affecting polishing performance.

[0007] Therefore, the purpose of this invention is to provide a polishing apparatus and polishing method that can polish a substrate with the required polishing performance without causing defects such as scratches and contamination.

[0008] [Technical means to solve the problem] In one embodiment, 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, the pad temperature adjusting device comprising: a pad heater disposed upwards and away from the polishing surface, the pad heater having: an elongated portion extending along the approximate radial direction of the polishing pad; and a slit-shaped nozzle formed along the long side of the elongated portion for spraying a heating fluid onto the polishing surface.

[0009] In one embodiment, the pad temperature adjustment device further includes a vertical movement mechanism that moves the pad heater vertically relative to the grinding surface. In one embodiment, the pad temperature adjustment device further includes a rotation mechanism that causes the pad heater to rotate horizontally relative to the grinding surface. In one embodiment, the pad temperature adjustment device further includes a rotating mechanism that causes the pad heater to rotate around its long side axis.

[0010] In one embodiment, the pad temperature adjustment device further includes a baffle mechanism for adjusting the opening of the injection port. In one embodiment, the pad temperature measuring device is a measuring device capable of measuring the temperature distribution of the abrasive pad along the radial direction, and the gate mechanism includes piezoelectric elements arranged along the long side of the nozzle of the pad heater. In one embodiment, the control device adjusts the expansion and contraction of each piezoelectric element based on the temperature distribution.

[0011] In one embodiment, the pad temperature adjustment device further includes a cooling mechanism that sprays cooling fluid onto the grinding surface to cool the grinding surface. In one embodiment, the cooling mechanism includes a pad cooler disposed away from the grinding surface facing upwards. The pad temperature adjustment device further includes a rotating mechanism that rotates the pad cooler around its long side axis. In one embodiment, the cooling mechanism includes: a pad cooler disposed above and away from the grinding surface; the pad cooler having: an elongated portion extending along the approximate radius of the grinding pad; and a plurality of injection nozzles arranged along the long side of the elongated portion for spraying the cooling fluid onto the grinding surface; the cooling mechanism further includes: a baffle mechanism for adjusting the opening of the plurality of injection nozzles of the pad cooler. In one embodiment, the cooling mechanism includes: a pad cooler disposed above and away from the grinding surface; the cooling mechanism further includes: a guide plate mounted on 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 grinding surface to suction air above the grinding surface.

[0012] In one embodiment, the pad temperature adjustment device further includes a heater, which is disposed within the pad heating machine. In one embodiment, the grinding table is disposed in the grinding chamber, and the pad temperature adjustment device further includes a grinding chamber suction device, which draws air from the grinding chamber in a manner that maintains the pressure inside the grinding chamber at a specified value. In one embodiment, it further includes a cleaning device for cleaning the pad heater at a retracted position to the side of the abrasive pad. In one embodiment, the heating fluid is superheated steam.

[0013] In one embodiment, when the control device begins to control the surface temperature of the polishing pad, it performs a pad temperature adjustment start-up action, which is to supply the pad heater with a heating fluid having a flow rate and / or temperature greater than the flow rate and / or temperature of the heating fluid calculated to achieve the target temperature of the polishing surface. In one embodiment, the pad temperature adjustment device further includes: a heating fluid supply line for supplying the heating fluid to the pad heater; and a flow regulator disposed on the heating fluid supply line, wherein the control device uses the flow regulator to increase the flow rate of the heating fluid during the start of the pad temperature adjustment operation. In one configuration, if the temperature of the grinding surface of the grinding pad reaches the target temperature, the control device ends the pad temperature adjustment and begins operation.

[0014] In one embodiment, a polishing method is provided in which a substrate is pressed against the polishing surface to polish the substrate while adjusting the temperature of the polishing surface of the polishing pad using a pad heater disposed above and away from the polishing surface. When the temperature of the polishing surface is controlled, a pad temperature adjustment start operation is performed to bring the temperature of the polishing surface to a target temperature. During the polishing of the substrate, based on the temperature of the polishing surface measured by a pad temperature measuring device, a heating fluid is injected from a slit-shaped nozzle formed in the elongated portion of the pad heater to maintain the temperature of the polishing surface at the target temperature. The pad temperature adjustment start operation is performed by supplying the heating fluid with a flow rate and / or temperature greater than the flow rate and / or temperature of the heating fluid calculated to bring the temperature of the polishing surface to the target temperature to the pad heater.

[0015] In one embodiment, the process of maintaining the temperature of the grinding surface at the target temperature is performed by at least one of the following adjustments: adjusting the temperature and / or flow rate of the heating fluid; adjusting the vertical movement of the pad heater relative to the grinding surface; adjusting the horizontal rotation of the pad heater relative to the grinding surface; and adjusting the rotational movement of the pad heater around its long side axis. In one embodiment, the flow rate of the heating fluid is adjusted using a baffle, which can adjust the opening of the nozzle of the pad heater. In one embodiment, the pad temperature measuring device is a measuring device capable of measuring the temperature distribution of the abrasive pad along the radial direction, the baffle includes piezoelectric elements arranged along the long side of the nozzle of the pad heater, and the flow rate of the heating fluid is adjusted by adjusting the extension and retraction of each piezoelectric element based on the temperature distribution.

[0016] In one embodiment, the process of maintaining the temperature of the grinding surface at the target temperature is performed using the pad heating machine and a cooling mechanism that cools the grinding surface by spraying cooling fluid onto it. In one embodiment, the cooling mechanism includes: a pad cooler disposed upwards and away from the grinding surface; the pad cooler having: an elongated portion extending along the approximate radius of the grinding pad; and a plurality of nozzles arranged along the long side of the elongated portion for spraying the cooling fluid onto the grinding surface; the process of maintaining the temperature of the grinding surface at the target temperature is performed by further adding at least one of the following adjustments: adjusting the rotational action of the pad cooler to rotate around its long side axis; adjusting the opening of the plurality of nozzles of the pad cooler based on a baffle; and adjusting the rotational action of a guide plate mounted on the pad cooler. In one embodiment, the pad temperature control begins by using a flow regulator configured in the heating fluid supply line of the pad heater to increase the flow rate of the heating fluid. In one configuration, if the temperature of the abrasive surface of the abrasive pad reaches the target temperature, the pad temperature adjustment start operation is terminated.

[0017] [The effects of the invention] 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. Therefore, the pad temperature adjustment device does not have structural elements that allow dirt such as abrasive particles contained in the polishing fluid and abrasive powder from the polishing pad to adhere. As a result, defects such as scratches and contamination caused by dirt detached from the pad temperature adjustment device can be prevented from occurring on the substrate. Furthermore, the surface condition of the polishing pad will not change due to dirt detached from the pad temperature adjustment device, thus enabling the substrate to be polished at the required polishing rate while maintaining the temperature of the polishing surface of the polishing pad at the predetermined target temperature. Simple Explanation of the Diagram

[0018] Figure 1 is a schematic diagram showing a grinding apparatus according to one embodiment. Figure 2 is a schematic diagram illustrating a heating fluid supply system and a cooling fluid supply system according to one embodiment. Figure 3(a) is a schematic diagram of a pad heating machine according to one embodiment, Figure 3(b) is a cross-sectional view of the pad heating machine shown in Figure 3(a), and Figure 3(c) is a top surface view showing an example of the configuration of the pad heating machine relative to the grinding pad 3. Figure 4(a) is a schematic diagram of a pad cooler according to one embodiment, and Figure 4(b) is a cross-sectional view of the pad cooler shown in Figure 4(a). Figure 5(a) is a schematic diagram of a suction nozzle according to one embodiment, and Figure 5(b) is a cross-sectional view of the suction nozzle shown in Figure 5(a). Figure 6(a) is a diagram showing an example of an integrally formed long strip of a pad heating machine and a long strip of a pad cooling machine, and Figure 6(b) is a schematic diagram showing an example of a shared long strip, which functions as both the long strip of the pad heating machine and the long strip of the pad cooling machine. Figure 7 is a schematic diagram illustrating an example of a vertical moving mechanism. Figure 8(a) is a schematic diagram showing an example of a rotating mechanism, and Figure 8(b) is a view of the upper surface of a pad heater rotated by the rotating mechanism. Figure 9(a) is a schematic diagram showing an example of a rotating mechanism that rotates the pad heating machine around its long side axis. Figure 9(b) is a cross-sectional view showing the state when the pad heating machine shown in Figure 9(a) is rotated upward. Figure 9(c) is a cross-sectional view showing the state when the pad heating machine shown in Figure 9(a) is rotated downward. Figure 10 is a schematic cross-sectional view of a pad heating machine according to another embodiment. Figure 11(a) is a perspective view of a gate mechanism of another embodiment viewed from the lower surface side, and Figure 11(b) is a schematic diagram showing an example of the operation of the gate mechanism shown in Figure 11(a). Figure 12 is a graph showing the target temperature distribution of the abrasive pad and an example of the temperature distribution obtained by the pad temperature measuring device. Figure 13 is a schematic cross-sectional view of a pad heating machine according to another embodiment. Figure 14 is a schematic diagram of a grinding apparatus including a pad temperature adjustment device according to another embodiment. Figure 15(a) is a schematic diagram of a pad cooler showing a cooling mechanism of another embodiment, and Figure 15(b) is a cross-sectional view of the pad cooler shown in Figure 15(a). Figure 16 is a cross-sectional view schematically showing a cooling mechanism of a pad cooler according to another embodiment. Figure 17 is a schematic diagram of a pad cooler, illustrating a cooling mechanism according to another embodiment. Figure 18 is a diagram illustrating an example of the start-up action of the pad temperature control. Figure 19 is a schematic diagram of a grinding apparatus including a pad temperature adjustment device according to another embodiment. Figure 20 is a schematic diagram illustrating a heating fluid supply system and a cooling fluid supply system according to another embodiment. Figure 21 is a schematic diagram illustrating a heating fluid supply system according to another embodiment. Figure 22 is a schematic diagram showing the combination of a cooling fluid supply system and a suction mechanism in another embodiment. Figure 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. Implementation

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a schematic diagram illustrating a polishing apparatus according to one embodiment. The polishing apparatus shown in Figure 1 includes: a polishing head 1, which holds and rotates a wafer W, which serves as a substrate; a polishing table 2, which supports a polishing pad 3; a polishing slurry supply nozzle 4, which supplies polishing slurry (e.g., a paste) to the surface of the polishing pad 3; a pad temperature sensor 10, which measures the temperature of the surface of the polishing pad 3; and a pad temperature adjustment device 5, which adjusts the surface temperature of the polishing pad 3. The surface (upper surface) of the polishing pad 3 constitutes the polishing surface of the wafer W.

[0020] Furthermore, the grinding apparatus includes a control device 40 that controls the operation of the pad temperature adjustment device 5 based on the temperature of the grinding surface of the grinding 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 overall operation of the grinding apparatus including the pad temperature adjustment device 5.

[0021] The polishing head 1 can move vertically and rotate in the direction indicated by the arrow, with its axis as the center. The wafer W is held on the lower surface of the polishing head 1 by vacuum adsorption or the like. A motor (not shown) is connected to the polishing table 2 and can rotate in the direction indicated by the arrow. As shown in Figure 1, the polishing head 1 and the polishing table 2 rotate in the same direction. The polishing pad 3 is attached to the upper surface of the polishing table 2.

[0022] The polishing of wafer W is performed as follows. Wafer W to be polished is held by polishing head 1 and rotated by polishing head 1. Meanwhile, polishing pad 3 rotates together with polishing table 2. In this state, polishing slurry is supplied to the surface of polishing pad 3 from polishing slurry supply nozzle 4, and the surface of wafer W is pressed against the surface of polishing pad 3 (i.e., the polishing surface) by polishing head 1. The surface of wafer W is polished by sliding against polishing pad 3 in the presence of polishing slurry. The surface of wafer W is planarized by the chemical action of polishing slurry and the mechanical action of the abrasive particles contained in the polishing slurry.

[0023] The pad temperature adjustment device 5 has a heating mechanism 9 for heating the grinding surface of the grinding pad 3. The heating mechanism 9 includes at least: a pad heater 11 disposed above the grinding pad 3; and a heating fluid supply system 30 for supplying heating fluid to the pad heater 11. By spraying the heating fluid supplied to the pad heater 11 via the heating fluid supply system 30 onto the grinding surface of the grinding pad 3, the grinding surface can be heated to a predetermined target temperature and maintained at this target temperature.

[0024] Furthermore, the pad temperature adjustment device 5 shown in FIG1 includes: a cooling mechanism 50 for spraying fluid onto the grinding surface of the grinding pad 3 to cool the grinding surface; and a suction mechanism 60 disposed above the grinding surface of the grinding pad 3.

[0025] The cooling mechanism 50 includes at least: a pad cooler 51 disposed above the abrasive pad 3; and a cooling fluid supply system 52 supplying cooling fluid to the pad cooler 51. The suction mechanism 60 includes at least: a suction nozzle 61 disposed above the abrasive pad 3; a vacuum source (vacuum device) 63; and a suction line 62 connecting 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 also include a flow regulator 64 disposed on the suction line 62. The flow regulator 64 is, for example, a damper.

[0026] The pad temperature measuring device 10 measures the surface temperature of the pad in a non-contact manner and sends the measured value to the control device 40. The pad temperature measuring device 10 can be an infrared radiation thermometer or a thermocouple thermometer that measures the surface temperature of the polishing pad 3, or it can be a temperature distribution measuring device that acquires the temperature distribution (temperature profile) of the polishing pad 3 along its radial direction. Examples of temperature distribution measuring devices include thermal imaging, thermopile, and infrared camera. When the pad temperature measuring device 10 is a temperature distribution measuring device, it is configured to measure the surface temperature distribution of the polishing pad 3, including the center and outer periphery of the polishing pad 3 and along the radial direction of the polishing pad 3. In this specification, temperature distribution (temperature profile) refers to the relationship between the pad surface temperature and its position in the radial direction 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 to maintain the pad surface temperature at a preset target temperature. Hereinafter, an example will be described where 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 also be a high-temperature gas (e.g., high-temperature air, nitrogen, or argon) or heating steam. Furthermore, superheated steam refers to high-temperature steam obtained by further heating saturated steam.

[0028] Furthermore, examples of using a gas at room temperature (e.g., an inert gas such as nitrogen or argon) as the cooling fluid will be described below. However, the cooling fluid is not limited to these examples. The cooling fluid may also 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. Considering the impact on the polishing slurry, an inert gas is preferred as the cooling fluid. However, the cooling fluid may also be a gas different from an inert gas, such as air.

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

[0030] The heating fluid supply system 30 shown in Figure 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 supplying water to the superheated steam generator 31; and a gas supply line 34 supplying ambient temperature gas to the superheated steam generator 31. The gas supply line 34 branches off from a main gas 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 the water supply line 33 with ambient temperature gas supplied from the gas supply line 34 to generate superheated steam adjusted to a specified temperature. The superheated steam is supplied to the pad heater 11 via the superheated steam supply line 32 and sprayed from the pad heater 11 onto the grinding surface of the grinding pad 3. This action raises the temperature of the grinding surface of the grinding pad 3.

[0032] The heating fluid supply system 30 shown in Figure 2 further includes: a flow regulator (first flow regulator) 35, disposed on 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 be used to adjust the flow rate of superheated steam supplied to the pad heater 11. Excess superheated steam is discharged from the grinding device through the exhaust line 36.

[0033] In one embodiment, the heating fluid supply system 30 may also replace the flow regulator 35 with an on / off valve (not shown). In this case, the on / off valve is opened by the control device 40, thereby supplying a specified flow rate of superheated steam (heating fluid) to the pad heater 11, which is then sprayed from the pad heater 11 onto the grinding surface of the grinding pad 3.

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

[0035] The cooling fluid supply system 52 shown in Figure 2 includes: a cooling gas supply line 53, branching from the main gas 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 control valve. The flow regulator 54 can be used to adjust the flow rate of the cooling gas supplied to the pad cooler 51. Cooling fluid is supplied to the pad cooler 51 via the cooling gas supply line 53 and sprayed from the pad cooler 51 onto the grinding surface of the grinding pad 3. This action reduces the temperature of the grinding surface of the grinding pad 3.

[0036] In one embodiment, the cooling fluid supply system 52 may also have an on / off valve (not shown) instead of the flow regulator 54. In this case, the on / off valve is opened by the control device 40, thereby supplying a specified flow rate of cooling gas (cooling fluid) to the pad cooler 51, from which it is sprayed onto the grinding surface of the grinding pad 3.

[0037] Control device 40 is connected to superheated steam generator 31, flow regulator 35, flow regulator 54, vacuum source 63, and flow regulator 64 (see Figure 1). Control device 40 controls the operation of at least one of the superheated steam generator 31, flow regulator 35, flow regulator 54, vacuum source 63, and flow regulator 64 based on the measured values ​​from pad temperature sensor 10, so that the pad surface temperature matches a predetermined target temperature. For example, control device 40 controls the operation of flow regulator 35 and flow regulator 54 to adjust the flow rate of superheated steam and the flow rate of cooling gas in a manner that ensures the pad surface temperature matches the predetermined target temperature.

[0038] The control device 40 may also control, in addition to controlling the operation of the flow regulators 35 and 54, or instead of controlling these operations, at least one of the following: 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 also adjust the temperature of the superheated steam generated by the superheated steam generator 31, or may adjust the amount of air drawn in by controlling the operation of the vacuum source 63 and / or the flow regulator 64. The temperature of the grinding surface can be adjusted by changing the temperature of the superheated steam injected into the grinding surface of the grinding pad 3. If the amount of air drawn in by the vacuum source 63 and / or the flow regulator 64 is increased or decreased, the amount of heat of vaporization removed from the slurry on the grinding surface changes, resulting in an adjustment of the temperature of the grinding surface.

[0039] In one embodiment, the operation of the vacuum source 63 and / or flow regulator 64 of the suction mechanism 60 can also be controlled to increase the amount of air drawn from the suction nozzle 61, thereby using the suction mechanism 60 as an auxiliary cooling mechanism for the cooling mechanism 50, or the cooling mechanism 50 can be omitted.

[0040] The pad temperature measuring device 10 (see Figure 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 maintains the pad surface temperature at a preset target temperature and, based on the measured pad surface temperature, performs proportional-integral-derivative (PID) control on the operating parameters of at least one of the superheated steam generator 31, flow regulator 35, flow regulator 54, vacuum source 63, and flow regulator 64.

[0041] The temperature control method of the control device 40 on the grinding surface of the grinding pad 3 is not limited to PID control, as long as the measured surface temperature of the pad can be maintained at the target temperature. Any control method can be used. For example, the control device 40 may also have the following artificial intelligence (AI) function: using a learned model constructed through machine learning to predict or determine at least one of the operating quantities of the superheated steam generator 31, flow regulator 35, flow regulator 54, vacuum source 63 and flow regulator 64.

[0042] Figure 3(a) is a schematic diagram showing one embodiment of the pad heater, Figure 3(b) is a cross-sectional view of the pad heater shown in Figure 3(a), and Figure 3(c) is a top surface view showing an example of the arrangement of the pad heater relative to the grinding pad 3. As shown in Figures 3(a) to 3(c), the pad heater 11 has: an elongated portion 11a extending in a generally radial direction along the grinding pad 3; and a nozzle 11b for spraying heating fluid onto the grinding surface of the grinding pad 3. A flow path for superheated steam (not shown) is formed inside the elongated portion 11a. The elongated portion 11a of the pad heater 11 preferably extends parallel to the grinding surface.

[0043] The nozzle 11b has a slit shape formed along the long side of the elongated portion 11a. The nozzle 11b is preferably oriented in an inclined direction relative to the imaginary surface P1, which passes through the central axis CL1 of the elongated portion 11a and extends in a vertical direction relative to the grinding surface of the grinding pad 3, such that the heated fluid obliquely impacts the grinding surface of the grinding pad 3.

[0044] The shape of the elongated section 11a is arbitrary, as long as the heated fluid can be sprayed from the nozzle 11b onto the grinding surface of the grinding pad 3. For example, the elongated section 11a can be cylindrical, or it can be a polygonal shape such as a square tube or a pentagonal tube.

[0045] Figure 4(a) is a schematic diagram of a pad cooler according to one embodiment, and Figure 4(b) is a cross-sectional view of the pad cooler shown in Figure 4(a). The pad cooler 51 shown in Figures 4(a) and 4(b) includes: an elongated portion 51a extending in a generally radial direction along the grinding pad 3; and a plurality of injection ports 51b for injecting cooling fluid onto the grinding surface of the grinding pad 3. A flow path for cooling gas (not shown) is formed inside the elongated portion 51a. The elongated portion 51a of the pad cooler 51 preferably extends parallel to the grinding surface.

[0046] Multiple nozzles 51b are arranged along the long side of the elongated portion 51a. In this embodiment, each nozzle 51b has a circular shape. Preferably, the nozzles 51b are oriented in an inclined direction relative to the surface P2, which passes through the central axis CL2 of the elongated portion 51a and extends vertically relative to the surface of the grinding pad 3, such that the cooling fluid obliquely impacts the grinding surface of the grinding pad 3.

[0047] The shape of the elongated portion 51a is arbitrary, as long as it allows cooling fluid to be sprayed from the injection port 51b onto the grinding surface of the grinding pad 3. For example, the elongated portion 51a may be cylindrical, or it may be a polygonal shape such as a square or pentagonal cylinder. Furthermore, the number and shape of the injection ports 51b are also arbitrary. For example, the injection port 51b may be an opening formed along the long side of the elongated portion 51a and having a slit shape, or multiple injection ports 51b may each have a square or triangular shape.

[0048] Figure 5(a) is a schematic diagram of a suction nozzle according to one embodiment, and Figure 5(b) is a cross-sectional view of the suction nozzle shown in Figure 5(a). The suction nozzle 61 shown in Figures 5(a) and 5(b) has: an elongated portion 61a extending in a generally radial direction along the abrasive pad 3; and a suction port 61b for drawing air above the abrasive surface of the abrasive pad 3. The suction port 61b preferably faces the abrasive surface. Inside the elongated portion 61a, a flow path (not shown) for the drawn air is formed. The elongated portion 61a of the suction nozzle 61 preferably extends parallel to the abrasive surface.

[0049] The shape of the suction nozzle 61 is arbitrary, as long as the required amount of air can be drawn from it. The number and shape of the suction ports 61b are also arbitrary. For example, the suction mechanism 60 may have multiple suction ports 61b arranged along the long side of the elongated portion 61a. In this case, each suction port 61b may be circular, square, or triangular. Furthermore, although not shown, the suction nozzle 61 may also have a domed top portion. In this case, the opening formed at the lowest part of the domed suction nozzle 61 functions as a suction port 61b. Furthermore, the domed suction nozzle 61 may also contain the elongated portion 11a of the pad heater 11 and / or the elongated portion 51a of the pad cooler 51.

[0050] As shown in Figure 6(a), the elongated section 11a of the pad heating machine 11 and the elongated section 51a of the pad cooling machine 51 can also be integrally formed. Alternatively, as shown in Figure 6(b), the pad temperature adjustment device 5 can also have a common elongated section 80, which functions as both the elongated section 11a of the pad heating machine 11 and the elongated section 51a of the pad cooling machine 51. In this case, the superheated steam supply line 32 and the cooling gas supply line 53 are connected to the common elongated section 80 via a mixing valve 81. By adjusting the valve opening of the mixing valve 81 through the control device 40, a mixture of superheated steam and cooling gas at the desired temperature is supplied to the common elongated section 80 and sprayed from the elongated section 80 onto the grinding surface of the grinding pad 3. For example, a slit-shaped injection port is formed along the long side of the elongated section 80.

[0051] When the pad temperature adjustment device 5 has a mixing valve 81, the control device 40 is configured to calculate the amount of operation of the mixing valve 81 required to eliminate the difference between the preset target temperature and the surface temperature of the polishing pad 3. The valve opening of the mixing valve 81 corresponds to the mixing ratio of superheated steam and cooling gas. By changing the amount of operation of the mixing valve 81, the control device 40 adjusts the mixing ratio of superheated steam and cooling gas, thereby adjusting the temperature of the mixed gas injected into the polishing pad 3 from the nozzle of the elongated section 80. The control device 40 controls the amount of operation of the mixing valve 81 (i.e., the valve opening of the mixing valve 81) so that the surface temperature of the polishing pad 3 matches the preset target temperature.

[0052] The arrangement order of the pad heater 11, pad cooler 51, and suction nozzle 61 is arbitrary. However, as shown in FIG1, it is preferable that the pad cooler 51 is positioned downstream of the pad heater 11 in the rotation direction of the grinding pad 3, and the suction nozzle 61 is positioned downstream of the pad cooler 51 in the rotation direction of the grinding 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 heating machine 11, the pad cooling machine 51, and the suction nozzle 61 are preferably arranged adjacent to each other and grounded. In this case, the pad heating machine 11, the pad cooling machine 51, and the suction nozzle 61 can also be connected to each other by connecting tools such as connecting rods, connecting blocks, or connecting arms (none shown). These connecting tools function as the base of the structure that integrates the pad heating machine 11, the pad cooling machine 51, and the suction nozzle 61 into a single unit.

[0054] According to this embodiment, the pad heating unit 11, the pad cooling unit 51, and the suction nozzle 61 are arranged above the polishing pad 3. That is, the pad temperature adjustment device 5 does not have structural elements for the adhesion of dirt such as abrasive particles contained in the polishing slurry and abrasive powder from the polishing pad 3. As a result, the wafer W will not develop defects such as scratches or contamination caused by dirt detached from the pad temperature adjustment device 5. Furthermore, the surface condition of the polishing pad 3 will not change due to dirt detached from the pad temperature adjustment device 5, thus enabling the wafer W to be polished at the required polishing rate.

[0055] As shown in Figure 7, the pad temperature adjustment device 5 may also include a vertical movement mechanism 85, which moves the pad heater 11 vertically relative to the grinding surface of the grinding pad 3. Figure 7 is a schematic diagram showing an example of the vertical movement mechanism 85.

[0056] The up-and-down movement mechanism 85 shown in Figure 7 includes: a support arm 86 connected to the pad heater 11; and an up-and-down movement actuator 87 that moves the pad heater 11 up and down via the support arm 86. The structure of the up-and-down movement actuator 87 is arbitrary as long as it allows the pad heater 11 to move in the up-and-down direction. For example, the up-and-down movement actuator 87 can be a piston-cylinder device including a piston that moves the pad heater 11 up and down via the support arm 86, or it can be a motor (e.g., a servo motor or a stepper motor) that moves the pad heater 11 up and down via the support arm 86. In one embodiment, the up-and-down movement actuator 87 can also 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 up-and-down movement mechanism 85 is connected to the control device 40. The control device 40 controls the operation of the up-and-down movement mechanism 85 (i.e., the operation amount of the up-and-down movement actuator 87) based on the measured value of the pad temperature measuring device 10, thereby changing the position of the pad heater 11 in the up-and-down direction relative to the grinding surface of the grinding pad 3 (see arrow A in Figure 3(b)). If the distance between the pad heater 11 and the grinding pad 3 changes, the temperature of the superheated steam that collides with the grinding surface of the grinding pad 3 changes. For example, if the pad heater 11 is brought closer to the grinding pad 3, the superheated steam with a high temperature collides with the grinding surface of the grinding pad 3, which can cause the pad surface temperature to rise. On the other hand, if the pad heater 11 is moved away from the grinding pad 3, the superheated steam with a low temperature collides with the grinding surface of the grinding pad 3, which can cause the pad surface temperature to decrease. Therefore, by changing the distance between the pad heater 11 and the grinding surface of the grinding pad 3, the pad surface temperature can be adjusted.

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

[0059] The rotation mechanism 90 shown in Figure 8(a) includes: a rotation spindle 91 connected to the pad heater 11 via a support arm 86; and a rotation actuator 92 that rotates the rotation spindle 91. The rotation actuator 92 is, for example, a motor (e.g., a servo motor or stepper motor) that rotates the rotation spindle 91, or a rotary cylinder. In one embodiment, the rotation actuator 92 may also be a piston cylinder with a piston. In this case, the rotation mechanism 90 has a link mechanism that converts the piston action of the piston cylinder into the rotational action of the rotation spindle 91.

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

[0061] As shown in Figure 8(b), if the pad heater 11 is rotated from its initial position (see Figure 3(c)) where the elongated portion 11a of the pad heater 11 extends approximately parallel to the long side of the grinding pad 3, the direction and amount of superheated steam colliding with the grinding surface of the grinding pad 3 change. As a result, the surface temperature of the pad 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 rotating mechanism 95 that rotates the pad heating machine 11 around its long side axis. Figure 9(b) is a cross-sectional view showing the state when the pad heating machine 11 shown in Figure 9(a) rotates upward. Figure 9(c) is a cross-sectional view showing the state when the pad heating machine 11 shown in Figure 9(a) rotates downward.

[0063] The rotating mechanism 95 shown in Figure 9(a) is mounted at the end of the pad heater 11 and includes a rotary actuator 96 that rotates the pad heater 11. The rotary actuator 96 is, for example, a servo motor or a stepper motor.

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

[0065] As shown in Figures 9(b) and 9(c), changing the direction of the nozzle 11b of the pad heater 11 relative to the grinding surface of the grinding pad 3 alters the amount and temperature of the superheated steam impacting the grinding surface of the grinding pad 3. As shown in Figure 9(b), rotating the pad heater 11 upwards reduces the amount and temperature of the superheated steam impacting the grinding surface of the grinding pad 3, thus lowering the pad surface temperature. As shown in Figure 9(c), rotating the pad heater 11 downwards increases the amount and temperature of the superheated steam impacting the grinding surface of the grinding pad 3, thus increasing the pad surface temperature. Therefore, by controlling the rotation angle of the pad heater 11 relative to the support arm 86, the pad surface temperature can be adjusted.

[0066] The pad temperature adjustment device 5 may also have any combination of two of the above-mentioned up-and-down moving mechanism 85, rotating mechanism 90 and rotating mechanism 95, or it may have all of the above-and-down moving mechanism 85, rotating mechanism 90 and rotating mechanism 95.

[0067] Figure 10 is a schematic cross-sectional view of a pad heater according to another embodiment. The pad heater 11 shown in Figure 10 also includes a gate mechanism 76, which includes a gate 77 for opening and closing the injection port 11b and an actuator 78 for driving the gate 77. In the example shown in Figure 10, the gate mechanism 76 has two gates 77, but it may also have only one gate 77. The actuator 78 may be, for example, a piston cylinder device including a piston that moves the gate 77, or it may be a motor (e.g., a servo motor or a stepper motor) that moves the gate 77. In one embodiment, the actuator 78 is a piezoelectric actuator that uses the piezoelectric effect of a piezoelectric element to move the gate 77.

[0068] Actuator 78 is connected to control device 40. Control device 40 controls the operation of actuator 78 (i.e., the amount of operation of actuator 78) based on the measured value of pad temperature measuring device 10, thereby controlling the opening of nozzle 11b. In this embodiment, the opening of nozzle 11b is equivalent to the width of nozzle 11b in the direction perpendicular to the long side. If the opening of nozzle 11b is changed, the flow rate and temperature of superheated steam colliding with the grinding surface of grinding pad 3 change, and the pad surface temperature changes. Therefore, by controlling the opening of nozzle 11b, the pad surface temperature can be adjusted.

[0069] Figures 11(a) and 11(b) are schematic diagrams illustrating a gate mechanism according to another embodiment. More specifically, Figure 11(a) is a perspective view of the gate mechanism according to another embodiment viewed from the lower surface, and Figure 11(b) is a schematic diagram illustrating an example of the operation of the gate mechanism shown in Figure 11(a). Unless otherwise specified, the structure of this embodiment is the same as that described with reference to Figure 10, and therefore, repeated descriptions are omitted.

[0070] The gate mechanism 76 shown in Figure 11(a) has a gate 77 comprising a plurality of piezoelectric elements 101. The plurality of piezoelectric elements 101 are arranged along the long side direction of the injection port 11b (i.e., along the long side direction of the strip portion 11a). In this embodiment, the strip portion 11a of the pad heater 11 has a rectangular cross-section, but as described above, the cross-sectional shape of the strip portion 11a is not limited to the example described. The gate 77 shown in Figure 11(a) adjusts the opening of the injection port 11b of the pad heater 11 by the extension and retraction action caused by 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 Figure 11(a), to avoid clutter, only control lines extending from the piezoelectric elements 101 to the piezoelectric element driver 103 are depicted. The control device 40 can independently control the extension and retraction of each piezoelectric element 101 by controlling the operation of the piezoelectric element driver 103 (see, for example, Figure 11(b)). The piezoelectric element driver 103 functions as an actuator to adjust the opening of the nozzle 11b of the pad heater 11.

[0072] When the pad temperature measuring device 10 is the temperature distribution measuring device described above, the control device 40 can acquire the temperature distribution (temperature profile) of the abrasive pad 3 along the radial direction of the abrasive pad 3. Figure 12 is a graph showing an example of the target temperature distribution of the abrasive pad and the temperature distribution acquired by the pad temperature measuring device. In Figure 12, the vertical axis represents the pad surface temperature, and the horizontal axis represents the radial position of the abrasive pad.

[0073] To precisely control the in-plane uniformity (flatness) of the entire surface of the polished wafer W, it is preferable to ensure that the temperature distribution is always consistent with the target temperature. Therefore, in this embodiment, the control device 40 controls the extension and retraction of each piezoelectric element 101 in such a way that the temperature distribution obtained by the pad temperature measuring device 10 is consistent with the target temperature. For example, as shown in FIG12, the control device 40 causes the piezoelectric element 101 corresponding to the position Pa of the polishing pad 3 where the difference between the target temperature and the measured temperature Da is large to contract significantly, thereby increasing the amount of superheated steam injected. On the other hand, the control device 40 causes the piezoelectric element 101 corresponding to the position Pb of the polishing pad 3 where the difference between the target temperature and the measured temperature Db is small to contract significantly, thereby further reducing the amount of superheated steam injected compared to the amount injected at position Pa.

[0074] The control device 40 controls the operation of the piezoelectric element driver 103 (i.e., the extension and retraction of each piezoelectric element 101) based on the measured values ​​of the pad temperature measuring device 10, thereby freely controlling the opening of the nozzle 11b along the radial direction of the polishing pad 3. As described above, changing the opening of the nozzle 11b changes the flow rate and temperature of the superheated steam colliding with the polishing surface of the polishing pad 3, and thus changes the surface temperature of the pad. By performing this pad temperature control, the overall temperature distribution of the polishing pad 3 can be made consistent with the target temperature. As a result, the wafer W can be polished precisely.

[0075] Figure 13 is a schematic cross-sectional view of a pad heater 11 according to another embodiment. Figure 13 shows a cross-section of the elongated section 11a of the pad heater 11. The pad heater 11 shown in Figure 13 has a heater 79 disposed inside the elongated section 11a. The heater 79 is also connected to a control device 40, which controls the operation of the heater 79 (e.g., ON / OFF operation). The heater 79 can be used to reheat the superheated steam that has cooled during its gradual flow from the superheated steam generator 31 to the pad heater 11. By reheating the superheated steam, adverse conditions such as condensation of the superheated steam in the pad heater 11 are prevented.

[0076] Figure 14 is a schematic diagram showing a grinding apparatus including a pad temperature adjustment device according to another embodiment. Figure 14 corresponds to the upper surface view of the grinding apparatus. Unless otherwise specified, the structure of this embodiment is the same as that of the described embodiment, and therefore repeated descriptions are omitted.

[0077] In the embodiment shown in Figure 14, structural elements such as the polishing table 2, polishing pad 3, and polishing head 1 are arranged in the polishing chamber PR, and the polishing of the wafer W is performed in the polishing chamber PR. The polishing chamber PR is a space divided by four partition walls 58, and the pressure inside it is maintained at a predetermined pressure (e.g., a lower pressure than the outside pressure of the polishing chamber PR). In addition, three of the four partition walls 58 are depicted in Figure 14.

[0078] If superheated steam is injected from the pad heater 11 and cooling gas is injected from the pad cooler 51, the pressure in the grinding chamber PR may rise further than the specified pressure, exceeding the allowable value set for the grinding chamber PR. Therefore, in this embodiment, the pad temperature adjustment device 5 includes a grinding chamber suction device 66, which draws air from the grinding chamber PR to maintain the pressure in the grinding chamber PR at a specified value. The grinding chamber suction device 66 shown in FIG14 includes a vacuum device 67 such as a vacuum pump and a suction pump; a grinding chamber suction line 68 extending from the grinding chamber PR; and a damper 69 disposed on the grinding chamber suction line 68.

[0079] Control device 40 is connected to damper 69. Control device 40 adjusts the opening of damper 69 to maintain the pressure in grinding chamber PR at a predetermined value. For example, control device 40 adjusts the opening of damper 69 so that the flow rate of air flowing in grinding chamber suction line 68 is equal to the sum of the measured values ​​of flow regulator 35 and flow regulator 54. In one embodiment, control device 40 may also be connected to vacuum device 67 to control the opening of damper 69 and / or the operation of vacuum device 67 to maintain the pressure in grinding chamber PR at a predetermined value.

[0080] Figure 15(a) is a schematic diagram of a pad cooler showing a cooling mechanism according to another embodiment, and Figure 15(b) is a cross-sectional view of the pad cooler shown in Figure 15(a). Unless otherwise specified, the structure of this embodiment is the same as that shown in Figures 4(a) and 4(b), and therefore, repeated descriptions are omitted.

[0081] The pad cooler 51 shown in Figures 15(a) and 15(b) further includes a gate mechanism 110, which includes gates 111 for opening and closing the injection ports 51b and an actuator 113 for driving the gates 111. In the example shown in Figure 15, the elongated portion 51a of the pad cooler 51 has a rectangular cross-section, and the gate mechanism 110 has a pair of gates 111 that can adjust the opening of all injection ports 51b. In one embodiment, the gate mechanism 110 may also have only one gate 111 that can adjust the opening of all injection ports 51b. The actuator 113 may be, for example, a piston cylinder device including a piston that moves the gate 111, or it may be a motor (e.g., a servo motor or a stepper motor) that moves the gate 111. In one embodiment, the actuator 113 may also be a piezoelectric actuator that uses the inverse piezoelectric effect of a piezoelectric element to move the gate 111.

[0082] Actuator 113 is connected to control device 40. Control device 40 controls the operation of actuator 78 or piezoelectric element driver 103 of pad heater 11 and the operation of actuator 113 (i.e., the operating amount of nozzle 51b) based on the measured value of pad temperature measuring device 10, thereby controlling the opening of nozzles 11b and 51b. In this embodiment, the opening of nozzle 51b corresponds to the width of nozzle 51b in the direction perpendicular to the long side. If the opening of nozzles 11b and 51b is changed, the flow rate and temperature of superheated steam and the flow rate and temperature of cooling gas on the grinding surface of the impact grinding pad 3 change, and the pad surface temperature changes. Therefore, by controlling the opening of nozzles 11b and 51b, the pad surface temperature can be precisely adjusted.

[0083] Figure 16 is a cross-sectional view schematically illustrating a cooling mechanism according to another embodiment of a pad cooler. As shown in Figure 16, the pad cooler 51 may also have a guide plate 120 mounted on the lower part of the pad cooler 51. Specifically, the guide plate 120 is mounted on the lower part of the elongated section 51a. The guide plate 120 may be a single plate extending throughout the entire elongated section 51a, or it may be multiple plates mounted corresponding to each spray nozzle 51b. The guide plate 120 has a shaft 120a at its end, which is rotatably mounted on a bearing 121 fixed to the lower surface of the elongated section 51a. The cooling mechanism 50 also has a rotation actuator 122 that rotates the guide plate 120 about the shaft 120a, and the rotation actuator 122 is connected to the control device 40.

[0084] If the guide plate 120 is rotated, the position and amount of cooling gas on the grinding surface of the impact grinding pad 3 will change. As a result, the surface temperature of the pad can also be adjusted by controlling the rotation angle of the guide plate 120.

[0085] In the case where the pad cooling machine 51 has multiple guide plates 120 installed corresponding to each spray nozzle 51b, the pad temperature measuring device 10 is preferably a temperature distribution measuring device that can acquire the temperature distribution 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 distribution 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 in a manner that the temperature distribution of the entire polishing pad 3 is consistent with the target temperature. As a result, the wafer W can be polished with precision.

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

[0087] The rotating mechanism 130 shown in Figure 17 is mounted at the end of the pad cooler 51 and includes a rotary actuator 131 that rotates the pad cooler 51. The rotary actuator 131 is, for example, a servo motor or a stepper motor.

[0088] The rotating mechanism 130 is connected to the control device 40. The control device 40 can control the operation of the rotating mechanism 130 (i.e., the operating amount of the rotating actuator 131) based on the measured value of the pad temperature measuring device 10, thereby changing the direction of the nozzle 51b of the pad cooler 51 relative to the grinding surface of the grinding pad 3. If the direction of the nozzle 51b of the pad cooler 51 relative to the grinding surface of the grinding pad 3 is changed, the amount and temperature of the cooling gas colliding with the grinding surface of the grinding pad 3 will change. Therefore, by controlling the rotation angle of the pad cooler 51 relative to the grinding surface of the grinding pad 3, the surface temperature of the pad can be adjusted.

[0089] In the pad temperature adjustment device 5 of the described embodiment, the control device 40 controls at least one of the following based on the measured values ​​of the pad temperature measuring device 10: the temperature, flow rate, injection quantity, injection position, and injection range of the superheated steam and cooling gas, thereby controlling the temperature of the grinding surface of the grinding pad 3. More specifically, the control device 40 controls at least one of the following based on the measured values ​​of the pad temperature measuring device 10: the flow rate regulator 35, the flow rate regulator 54, the superheated steam generator 31, the up-and-down moving mechanism 85, the rotating mechanism 90, the rotating mechanism 130, the gate mechanism 77, the gate mechanism 110, the heater 79, the mixing valve 81, and the guide plate 120, thereby bringing the temperature of the grinding surface of the grinding pad 3 to the target temperature and maintaining it at the target temperature. This allows the wafer W to be precisely ground to the desired film thickness. Especially in embodiments where the gate 77 includes multiple piezoelectric elements 10, and where the pad cooler 51 has multiple guide plates 120 installed corresponding to each injection port 51b, the temperature distribution of the entire grinding pad 3 can be made consistent with the target temperature.

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

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

[0092] In this manual, the control action that temporarily increases the flow rate and / or temperature of superheated steam when the surface temperature of the polishing pad 3 is first controlled is referred to as "pad temperature control start action". Furthermore, in this manual, the flow rate and temperature of superheated steam calculated in order to make the surface temperature of the polishing pad 3 reach the target temperature are referred to as "set flow rate" and "set temperature", respectively.

[0093] During the initial operation of the pad temperature control, the control device 40, for example, controls the operation of the flow regulator 35 to further increase the flow rate of superheated steam ejected from the nozzle 11b of the pad heater 11 compared to the set flow rate. Alternatively, during the initial operation of the pad temperature control, the control device 40 may also control the operation of the superheated steam generator 31 and / or the heater 79 to further increase the temperature of the superheated steam ejected from the nozzle 11b of the pad heater 11 compared to the set temperature. The control device 40 may also control the operation of the flow regulator 35 and the superheated steam generator 31 and / or the heater 79 to further increase the flow rate and temperature of the superheated steam ejected from the nozzle 11b of the pad heater 11 compared to the set flow rate and set temperature. Through these actions, the pad surface temperature can be brought to the target temperature as quickly as possible.

[0094] Figure 18 is a graph illustrating an example of the pad temperature adjustment initiation operation. In the graph shown in Figure 18, the vertical axis represents the pad surface temperature, and the horizontal axis represents time. In Figure 18, the target temperature is depicted by a solid horizontal line, and the change in pad surface temperature when the pad temperature adjustment initiation operation is performed is depicted by a single-point chain line. In Figure 18, the curve depicted by a two-point chain line represents the change in pad surface temperature when the pad temperature adjustment initiation operation is not performed. Point Ts in Figure 18 represents the time point at which the pad temperature adjustment device 5 begins to adjust the temperature of the grinding pad 3.

[0095] As described above, during the initial operation of the pad temperature control, the flow rate and / or temperature of the superheated steam are temporarily increased further than the set flow rate and / or set temperature. Figure 18 shows the graph where the flow rate of the superheated steam is further increased than the set flow rate. The following describes the initial operation of the pad temperature control by injecting superheated steam at a flow rate greater than the set flow rate. The initial operation of the pad temperature control by injecting superheated steam at a temperature greater than the set temperature can also be performed using the same control action.

[0096] As shown in Figure 18, the control device 40 pre-stores a set time Ta, which specifies the maximum execution time for the pad temperature adjustment to begin. The set flow rate and set time Ta can be arbitrarily specified. For example, the set time Ta can also be obtained through the following experiment: In a state where the pad temperature adjustment is not initiated, a specified flow rate of superheated steam is injected from the nozzle 11b of the pad heater 11 onto the grinding surface of the grinding pad 3. In this experiment, the time from the start of temperature adjustment of the grinding pad 3 until the pad surface temperature reaches the target temperature is measured, and this measured time is determined as the set time Ta.

[0097] The control device 40 calculates the flow rate of superheated steam required to bring the pad surface temperature to the target temperature during the period from the start of temperature adjustment of the polishing pad 3 (i.e., time Ts) to the arrival of a set time Ta. To execute the pad temperature adjustment start operation, the control device 40 injects superheated steam from the nozzle 11b of the pad heater 11 at a flow rate greater than the calculated superheated steam flow rate. As a result, the pad surface temperature quickly reaches the target temperature, thus allowing the polishing conditions of the wafer W to quickly reach their optimal levels.

[0098] During the execution of the pad temperature adjustment initiation, the control device 40 stops the operation of the cooling mechanism 50 and the suction mechanism 60. At the point when the pad surface temperature reaches the target temperature (refer to time point Tb in Figure 18), the control device 40 terminates the pad temperature adjustment initiation and begins normal pad temperature adjustment control to maintain the pad surface temperature at the target temperature. More specifically, the control device 40 initiates the operation of the cooling mechanism 50 and the suction mechanism 60, starting normal control by controlling at least one of the following: the temperature, flow rate, injection quantity, injection position, and injection range of the superheated steam and cooling gas. This minimizes overshoot, which occurs when the pad surface temperature exceeds the target temperature.

[0099] Even if the pad surface temperature has not reached the target temperature, but the elapsed time since the start of pad temperature adjustment, measured from time Ts, reaches the set time Ta, the control device 40 will still begin the following normal control: controlling at least one of the temperature, flow rate, injection quantity, injection position, and injection range of the superheated steam and cooling gas. In one embodiment, the control device 40 may also determine that the pad temperature adjustment device 5 is malfunctioning and stop the polishing process of the wafer W.

[0100] Figure 19 is a schematic diagram showing a grinding apparatus including a pad temperature adjustment device according to another embodiment. Unless otherwise specified, the structure of this embodiment is the same as that described above, and therefore repeated descriptions are omitted.

[0101] The pad temperature adjustment device 5 shown in Figure 19 includes: a cleaning device 45 in a retracted position to the side of the abrasive pad 3, a cleaning pad heater 11, a pad cooler 51, and a suction nozzle 61. A control device 40 is connected to the cleaning device 45 and controls the operation of the cleaning device 45. Furthermore, Figure 19 only depicts the pad heater 11, pad cooler 51, suction nozzle 61, and cleaning device 45 of the pad temperature adjustment device 5; illustrations of other structural components are omitted.

[0102] In this embodiment, the pad temperature adjustment device 5 includes the rotating mechanism 90. The control device 40 causes the rotating actuator 92 of the rotating mechanism 90 (refer to Figure 8(a)) to work, so that the pad heater 11, the pad cooler 51 and the suction nozzle 61 move from the initial position shown in Figure 3(c) to the retraction position shown in Figure 19.

[0103] The cleaning device 45 includes multiple sprayers 46 that spray cleaning fluid (e.g., pure water) from above and below onto the pad heater 11, pad cooler 51, and suction nozzle 61, which have been moved to a retracted position. After the pad heater 11, pad cooler 51, and suction nozzle 61 have moved to the retracted position, the control device 40 sprays cleaning fluid onto the pad heater 11, pad cooler 51, and suction nozzle 61 from the sprayers 46. Through this action, dirt adhering to the pad heater 11, pad cooler 51, and suction nozzle 61 is cleaned.

[0104] Once the cleaning of the pad heater 11, pad cooler 51, and suction nozzle 61 is complete, the control device 40 controls the rotation mechanism 90 to move the pad heater 11, pad cooler 51, and suction nozzle 61 to their initial positions (see Figure 3(c)). If cleaning fluid droplets drip from the pad heater 11, pad cooler 51, and suction nozzle 61, which have moved to their initial positions, onto the grinding pad 3, the concentration of the grinding fluid (slurry) may change, adversely affecting the grinding performance. Therefore, in this embodiment, the cleaning device 45 may also include multiple nozzles 47 that spray gas (e.g., air, nitrogen, or argon) onto the pad heater 11, pad cooler 51, and suction nozzle 61 after cleaning with the cleaning fluid.

[0105] The cleaning fluid adhering to the pad heater 11, pad cooler 51, and suction nozzle 61 can be blown away by the gas sprayed from the nozzle 47, thereby drying the pad heater 11, pad cooler 51, and suction nozzle 61. This drying process prevents cleaning fluid droplets from dripping from the pad heater 11, pad cooler 51, and suction nozzle 61, which have moved to their initial positions, onto the abrasive pad 3. In one embodiment, the injector 46 may also have the function of spraying gas onto the pad heater 11, pad cooler 51, and suction nozzle 61 independently of the cleaning fluid.

[0106] In the described embodiment, the pad temperature adjustment device 5 includes not only the pad heater 11, but also a cooling mechanism 50 and a suction mechanism 60. However, the pad temperature adjustment 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, the pad temperature adjustment device 5 preferably has at least one of the up-and-down moving mechanism 85, the rotating mechanism 90, and the rotary mechanism 95. These mechanisms 85, 90, and 95 allow for fine adjustment of the pad surface temperature.

[0107] Figure 20 is a schematic diagram illustrating a heating fluid supply system and a cooling fluid supply system according to another embodiment. Unless otherwise specified, the structure of this embodiment is the same as that of the embodiment shown in Figure 2, and therefore, repeated descriptions are omitted.

[0108] The heating fluid supply system 30 shown in Figure 20 includes: a thermometer 71 disposed on a superheated steam supply line 32; and a flow meter 72 and a flow regulator 73 (e.g., a flow control valve) disposed on a gas supply line 34. The thermometer 71 is connected to a control device 40 and sends the measured value of the superheated steam temperature 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 sends the measured value of the flow rate of the gas flowing in 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 in such a way that the temperature of the superheated steam flowing in the superheated steam supply line 32 is consistent with the calculated steam temperature.

[0110] The control device 40 may also control the operation of the flow regulator 73 based on the pad surface temperature measured by the pad temperature measuring device 10, in addition to controlling the operation of the superheated steam generator 31. 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 in the gas supply line 34. The control device 40 controls the operation of the superheated steam generator 31 and / or the flow regulator 73 in such a way that the temperature of the superheated steam flowing in the superheated steam supply line 32 matches the calculated steam temperature, and / or the flow rate of the gas flowing in the gas supply line 34 matches the calculated gas flow rate.

[0111] Figure 21 is a schematic diagram illustrating a heating fluid supply system according to another embodiment. Unless otherwise specified, the structure of this embodiment is the same as the heating fluid supply system of the embodiment shown in Figure 2, and therefore, a repeated description is omitted.

[0112] The heating fluid supply system shown in Figure 21 has a drain tank 37 connected to an exhaust line 36. A water branch line 38, branching from the water supply line 33, is also connected to the drain tank 37, and a valve 39 is installed on the water branch line 38. Opening the valve 39 supplies room temperature water to the drain tank 37.

[0113] Excess superheated steam flowing through exhaust line 36 is supplied to drain tank 37, where it condenses and reduces to water. To ensure efficient condensation of the excess superheated steam, ambient temperature water is supplied to drain tank 37 through water branch line 38, thus lowering the ambient temperature inside drain tank 37. At the bottom of drain tank 37, a drain line 83 is connected, through which the condensed water from the superheated steam is discharged from the grinding device.

[0114] Although not illustrated, the water branch line 38 can be omitted, and the drain line 83 can be connected to the superheated steam generator 31. In this case, the high-temperature water accumulated in the drain tank 37 is supplied to the superheated steam generator 31 and used again to generate superheated steam. Based on this structure, energy-efficient operation of the superheated steam generator 31 can be expected.

[0115] Figure 22 is a schematic diagram showing the 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 Figure 22 is an ejector. For the vacuum source 63, a gas branch line 55 is connected to branch off from the cooling gas supply line 53 of the cooling fluid supply system 52. The driving fluid for the vacuum source 63 is ambient temperature gas supplied to the vacuum source 63 through the gas branch line 55. A flow regulator 74 (e.g., a flow control valve) is disposed on the gas branch line 55 to adjust the flow rate of the driving fluid. This structure can be used to reduce the operating cost of the vacuum source 63.

[0116] Figure 23 is a schematic diagram showing the combination of a heating fluid supply system 30, a cooling fluid supply system 50, and a suction mechanism 60 according to another embodiment. Embodiments not specifically described are the same as those described with reference to Figures 21 and 22, and therefore their descriptions are omitted.

[0117] In the cooling fluid supply system 50 shown in Figure 23, a gas branch line 56, different from the gas branch line 55 used to supply driving fluid to the vacuum source 63, which serves as an ejector, branches off from the cooling gas supply line 53. In the following description, the gas branch line 55 will be referred to as the first branch line 55, and the gas branch line 56 will be referred to as the second branch line 56.

[0118] The second branch line 56 is connected to the exhaust line 36. The ambient temperature gas flowing from the second branch line 56 to the exhaust line 36 mixes with excess superheated steam in the exhaust line 36, cooling the superheated steam. Therefore, cooled superheated steam and water condensed from the superheated steam are supplied to the drain tank 37.

[0119] A gas release line 41 is connected to the drain tank 37, and the gas release line 41 is connected to the discharge line 65 of the vacuum source 63, which serves as an ejector. The gas flowing from the exhaust line 36 to the drain tank 37 flows into the discharge line 65 through the gas release line 41, and is discharged from the grinding device via the discharge line 65.

[0120] The embodiments described are intended to enable those skilled in the art to practice the invention. Various modifications of the embodiments will naturally occur to those skilled in the art, and the technical concept of the invention can be applied to other embodiments. Therefore, the invention is not limited to the described embodiments, but is interpreted in the broadest possible sense, following the technical concept defined in the claims.

[0121] 1: Grinding head 2: Grinding table 3: Grinding pad 4: Grinding fluid supply nozzle 5: Pad temperature adjustment device 9: Heating mechanism 10: Pad Temperature Measuring Instrument 11: Pad heating machine 11a, 51a, 61a, 80: Long strip section 11b, 51b: Injection nozzle 30: Heating fluid supply system 31: Superheated Steam Generator 32: Superheated Steam Supply Line 33: Water Supply Line 34: Gas supply line 35, 54, 64, 73, 74: Flow regulator 36: Exhaust line 37: Drainage tank 38: Water branch line 39: Valve 40: Control device 41: Gas release line 45: Cleaning device 46: Injector 47: Nozzle 50: Cooling mechanism 51: Pad Cooler 52: Cooling fluid supply system 53: Cooling gas supply line 58: Isolation Wall 60: Suction mechanism 61: Suction nozzle 61b: Suction port 62: Suction line 63: Vacuum source (vacuum device) 65: Exhaust line 66: Grinding chamber suction device 67: Vacuum device 68: Grinding chamber suction line 69: Dampers 70: Gas Mainline 71: Thermometer 72: Flow meter 76, 110: Barrier mechanism 77, 111: Barrier 78, 113: Actuators 79: Heater 81: Mixing valve 83: Drainage line 85: Up and down moving mechanism 86: Support arm 87: Up and down movement actuator 90: Rotating mechanism 91: Rotate the spindle 92, 122: Rotary actuator 95, 130: Rotating mechanism 96, 131: Rotary actuator 101: Piezoelectric element 103: Piezoelectric element actuator 120: Guide board 120a: Shaft 121: Bearing CL1, CL2: Central axis Da, Db: Temperature difference P1: Imaginary Face P2: Face PR: Grinding Chamber Pa, Pb: Position Ta: Set Time Tb: Time point Ts: Time W: substrate

Claims

1. A grinding apparatus, comprising: A grinding table, used to support the grinding pad; A grinding head presses the substrate against the grinding surface of the grinding pad to grind the substrate; A pad temperature measuring device measures the temperature of the grinding surface; a pad temperature adjusting device adjusts the temperature of the grinding surface; and a control device controls the operation of the pad temperature adjusting device based on the temperature of the grinding surface measured by the pad temperature measuring device. The pad temperature adjusting device includes a pad heater disposed upwards and away from the grinding surface. The pad heater has an elongated portion extending along the approximate radius of the grinding pad and a slit-shaped nozzle formed along the long side of the elongated portion for spraying a heating fluid onto the grinding surface. The pad temperature adjusting device further includes a baffle mechanism for adjusting the opening of the nozzle. The pad temperature measuring device is capable of measuring the temperature distribution of the grinding pad along the radial direction. The baffle mechanism includes piezoelectric elements arranged along the long side of the nozzle of the pad heater. The control device independently adjusts the extension and retraction of each piezoelectric element based on the temperature distribution.

2. The grinding apparatus as claimed in claim 1, wherein, The pad temperature adjustment device further includes a vertical movement mechanism that moves the pad heater vertically relative to the grinding surface.

3. The grinding apparatus as described in claim 1 or 2, wherein, The pad temperature adjustment device further includes a rotation mechanism that causes the pad heater to rotate horizontally relative to the grinding surface.

4. The grinding apparatus as described in claim 1 or 2, wherein, The pad temperature adjustment device further includes a rotating mechanism that allows the pad heater to rotate around its long side axis.

5. The grinding apparatus as described in claim 1 or 2, wherein, The pad temperature adjustment device further includes a cooling mechanism that sprays cooling fluid onto the grinding surface to cool the grinding surface.

6. The grinding apparatus as claimed in claim 5, wherein, The cooling mechanism includes a pad cooler disposed upwards from the grinding surface. The pad temperature adjustment device further includes a rotation mechanism that rotates the pad cooler around its long side axis.

7. The grinding apparatus as claimed in claim 5, wherein, The cooling mechanism includes: a pad cooler disposed upwards from the grinding surface, the pad cooler having: an elongated portion extending along the approximate radius of the grinding pad; The cooling mechanism also includes a plurality of spray nozzles arranged along the long side of the strip for spraying the cooling fluid onto the grinding surface. The cooling mechanism further includes a baffle mechanism for adjusting the opening of the plurality of spray nozzles of the pad cooler.

8. The grinding apparatus as claimed in claim 5, wherein, The cooling mechanism includes: a pad cooler disposed above the grinding surface and away from the ground; the cooling mechanism also includes: a guide plate mounted on the pad cooler; and an actuator for rotating the guide plate.

9. The grinding apparatus as claimed in claim 1 or 2, wherein, The pad temperature adjustment device further includes a suction mechanism, which is disposed above the grinding surface to suction the air above the grinding surface.

10. The grinding apparatus as claimed in claim 1 or 2, wherein, The pad temperature adjustment device further includes a heater, which is disposed inside the pad heating machine.

11. The grinding apparatus as claimed in claim 1 or 2, wherein, The grinding table is disposed in the grinding chamber, and the pad temperature adjustment device further includes: a grinding chamber suction device, which draws air from the grinding chamber in a manner that maintains the pressure in the grinding chamber at a specified value.

12. The grinding apparatus as described in claim 1 or 2, further comprising: A cleaning device cleans the pad heater at a retracted position to the side of the abrasive pad.

13. The grinding apparatus as claimed in claim 1 or 2, wherein, The heating fluid is superheated steam.

14. The grinding apparatus as claimed in claim 1 or 2, wherein, When the control device begins to control the surface temperature of the polishing pad, it performs a pad temperature adjustment start action, which is to supply the pad heater with a heating fluid having a flow rate and / or temperature greater than the flow rate and / or temperature of the heating fluid calculated to make the polishing surface reach the target temperature.

15. The grinding apparatus as claimed in claim 14, wherein, The pad temperature adjustment device further includes: a heating fluid supply line for supplying the heating fluid to the pad heater; and a flow regulator disposed on the heating fluid supply line, wherein the control device uses the flow regulator to increase the flow rate of the heating fluid during the start of the pad temperature adjustment operation.

16. The grinding apparatus as claimed in claim 14, wherein, If the temperature of the grinding surface of the grinding pad reaches the target temperature, the control device will stop the pad temperature adjustment and start the operation.

17. A polishing method comprising: polishing a substrate by pressing it against the polishing surface using a pad heater disposed above and away from the polishing surface; and, upon initiating temperature control of the polishing surface, performing a pad temperature adjustment initiation operation to bring the temperature of the polishing surface to a target temperature; wherein, during the polishing of the substrate, based on the temperature of the polishing surface measured by a pad temperature measuring device, a heating fluid is injected from a slit-shaped nozzle formed in the elongated portion of the pad heater to maintain the temperature of the polishing surface at the target temperature; the pad temperature adjustment initiation operation comprises supplying the pad heater with a heating fluid having a flow rate and / or temperature greater than that calculated for bringing the temperature of the polishing surface to the target temperature. The process of maintaining the temperature of the grinding surface at the target temperature is performed by at least one of the following adjustments: adjusting the temperature and / or flow rate of the heating fluid; adjusting the vertical movement of the pad heater relative to the grinding surface; adjusting the horizontal rotation of the pad heater relative to the grinding surface; and adjusting the rotational movement of the pad heater around its long side axis. The adjustment of the flow rate of the heating fluid is performed using a baffle, which can adjust the opening of the nozzle of the pad heater. The pad temperature measuring device is a measuring device capable of measuring the temperature distribution of the grinding pad along the radial direction. The baffle includes piezoelectric elements arranged along the long side of the nozzle of the pad heater. The adjustment of the flow rate of the heating fluid is performed by independently adjusting the extension and retraction of each piezoelectric element based on the temperature distribution.

18. The grinding method as described in claim 17, wherein, The process of maintaining the temperature of the grinding surface at the target temperature is performed using the pad heating machine and a cooling mechanism that cools the grinding surface by spraying cooling fluid onto it.

19. The grinding method as described in claim 18, wherein, The cooling mechanism includes: a pad cooler disposed upwards and away from the grinding surface; the pad cooler having: an elongated portion extending along the approximate radius of the grinding pad; and a plurality of nozzles arranged along the long side of the elongated portion for spraying the cooling fluid onto the grinding surface; the process of maintaining the temperature of the grinding surface at the target temperature is performed by further adding at least one of the following adjustments: adjusting the rotational action of the pad cooler to rotate about its long side axis; adjusting the opening of the plurality of nozzles of the pad cooler based on a baffle; and adjusting the rotational action of a guide plate mounted on the pad cooler.

20. The grinding method as described in claim 17, wherein, The pad temperature control starts by using a flow regulator configured in the heating fluid supply line of the pad heater to increase the flow rate of the heating fluid.

21. The grinding method as described in claim 17, wherein, If the temperature of the grinding surface of the grinding pad reaches the target temperature, the pad temperature adjustment start-up operation ends.

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