Polishing method and polishing apparatus

Abstract

To provide a polishing method in which an accurate film thickness profile can be obtained.SOLUTION: In a polishing method, the temperature of an abrasive surface 3a of a polishing pad 3 is adjusted to a predetermined temperature using a pad temperature adjusting device 5, and then a substrate W is polished while controlling a polishing load with which the substrate W is pressed against the abrasive surface 3a, in accordance with a measurement value of a film thickness measuring instrument 7 provided on the polishing pad 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a polishing method and a polishing apparatus for polishing a substrate such as a wafer while pressing the substrate against a polishing surface of a polishing pad, and more particularly to a polishing method and a polishing apparatus for polishing a substrate while adjusting a polishing load based on a measurement value of a film thickness measuring device.

Background Art

[0002] A CMP (Chemical Mechanical Polishing) apparatus is a polishing apparatus used in the process of polishing the surface of a substrate such as a wafer in the manufacture of semiconductor devices. The CMP apparatus holds the substrate with a polishing head and rotates the substrate, and further presses the substrate against a polishing pad on a rotating polishing table to polish the surface of the substrate. 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 abrasive grains contained in the polishing liquid.

[0003] When polishing a substrate with a CMP apparatus, it is important to accurately detect a change in the state of the substrate surface for detecting the end point of polishing of the substrate and adjusting the polishing conditions of the substrate. For example, over-polishing and under-polishing with respect to the target polishing end point directly lead to product defects, so it is necessary to strictly control the polishing amount. Therefore, some CMP apparatuses are provided with a film thickness measuring device for measuring the film thickness of the substrate during polishing of the substrate (see, for example, Patent Document 1). This film thickness measuring device is installed, for example, inside the polishing table, and generates a film thickness signal indicating the film thickness of a plurality of regions of the substrate every time the polishing table makes one rotation. When the film thickness of the substrate indicated by the film thickness signal reaches a predetermined target thickness, the CMP apparatus issues commands to the polishing head and the polishing table to finish polishing the substrate.

[0004] The polishing head has, at its lower part, an elastic film that forms a plurality of pressure chambers for pressing the substrate against the polishing pad. By supplying a pressurized fluid such as compressed air to each pressure chamber, the substrate is pressed against the polishing pad by fluid pressure via the elastic film. The fluid pressure supplied to each pressure chamber is determined by the film thickness of each region of the substrate measured by a film thickness measuring device. For example, the fluid pressure supplied to each pressure chamber (i.e., the polishing load of the substrate against the polishing pad) is adjusted based on Preston's empirical rule that the polishing rate is proportional to the pressing force pressing the substrate against the polishing pad. That is, when increasing the polishing rate, the fluid pressure is increased, and when decreasing the polishing rate, the fluid pressure is decreased. With such a configuration, the pressing force for pressing the substrate against the polishing pad can be adjusted for each region of the substrate, so that the entire surface of the substrate is polished to a uniform thickness.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, due to the frictional heat generated by pressing the rotating substrate against the rotating polishing pad, the temperature of the polishing pad gradually rises during the polishing of the substrate. The polishing rate of the substrate depends not only on the polishing load of the substrate against the polishing pad but also on the surface temperature of the polishing pad. This is because the chemical action of the polishing liquid on the substrate depends on the temperature.

[0007] FIG. 20(a) is a diagram showing an example of the relationship between the polishing rate and the polishing temperature when polishing a substrate with a predetermined polishing load, and FIG. 20(b) is a diagram showing another example of the relationship between the polishing rate and the polishing temperature when polishing a substrate with a predetermined polishing load. In FIGS. 20(a) and 20(b), the vertical axis represents the polishing rate, and the horizontal axis represents the polishing temperature (with respect to the temperature of the surface of the polishing pad). The graphs shown in FIGS. 20(a) and 20(b) are graphs showing the relationship between the polishing rate and the polishing temperature when polishing a substrate with a constant polishing load, respectively, but the types of films formed on the substrate and the types of polishing liquids are different.

[0008] As shown in FIG. 20(a), when the polishing load is constant, generally, as the polishing temperature increases, the polishing rate also increases. Therefore, when the temperature of the polishing pad increases due to the frictional heat generated between the substrate and the polishing pad, the polishing rate also increases. If the polishing rate increases too much, it may become difficult to polish the substrate with an accurate film thickness profile. Furthermore, if the polishing rate exceeds the resolution of polishing end point detection (i.e., the polishing amount per rotation of the polishing table), it becomes impossible to detect the polishing end point with high precision, and there is a risk of over-polishing.

[0009] As shown in FIG. 20(b), depending on the type of film to be polished, there is a turning point TP at which the polishing rate that increases as the polishing temperature increases turns to decrease. When the polishing temperature exceeds the turning point TP, the polishing rate decreases, so the CMP apparatus increases the fluid pressure supplied to each pressure chamber. Then, the surface temperature of the polishing pad further increases, and the polishing rate decreases, which may result in a decrease in the throughput of the polishing apparatus.

[0010] Therefore, an object of the present invention is to provide a polishing method capable of obtaining an accurate film thickness profile. Another object of the present invention is to provide a polishing apparatus capable of obtaining an accurate film thickness profile.

Means for Solving the Problems

[0011] In one aspect, a polishing method is provided in which the temperature of the polishing surface of a polishing pad is adjusted to a predetermined temperature using a pad temperature adjusting device, and the substrate is polished while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of a film thickness measuring device provided on the polishing pad.

[0012] In one aspect, the step of polishing the substrate starts immediately after the temperature of the polishing surface reaches the predetermined temperature. In one aspect, the step of polishing the substrate starts after the temperature of the polishing surface has stabilized at the predetermined temperature. In one aspect, the step of polishing the substrate is performed while maintaining the temperature of the polishing surface at the predetermined temperature.

[0013] In one aspect, the predetermined temperature is a first predetermined temperature, and the step of polishing the substrate includes a first polishing in which the substrate is polished at the first predetermined temperature while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of the film thickness measuring device, and a second polishing in which the substrate is polished at a second predetermined temperature different from the first predetermined temperature while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of the film thickness measuring device. The switching from the first polishing to the second polishing is performed when the amount of the remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount. In one aspect, the predetermined temperature is a first predetermined temperature, and the step of polishing the substrate includes a first polishing in which the substrate is polished at the first predetermined temperature while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of the film thickness measuring device, and a second polishing in which the substrate is polished at a second predetermined temperature that gradually changes from the first predetermined temperature while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of the film thickness measuring device. The switching from the first polishing to the second polishing is performed when the amount of the remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount.

[0014] In one aspect, there is provided a polishing apparatus including a polishing table for supporting a polishing pad, a polishing head for pressing 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 adjusting device for adjusting the temperature of the polishing surface, a film thickness measuring device attached to the polishing table, and a control device for controlling at least the operations of the polishing head and the pad temperature adjusting device. The control device adjusts the temperature of the polishing surface to a predetermined temperature using the pad temperature adjusting device based on a measurement value of the pad temperature measuring device, and polishes the substrate while controlling a polishing load for pressing the substrate against the polishing surface based on a measurement value of the film thickness measuring device.

[0015] In one aspect, the control device starts polishing the substrate immediately after the temperature of the polishing surface reaches the predetermined temperature. In one aspect, the control device starts polishing the substrate after the temperature of the polishing surface stabilizes at the predetermined temperature. In one aspect, the control device polishes the substrate while maintaining the temperature of the polishing surface at the predetermined temperature.

[0016] In one aspect, the predetermined temperature is a first predetermined temperature. The polishing of the substrate includes a first polishing at the first predetermined temperature, in which the substrate is polished while controlling a polishing load for pressing the substrate against the polishing surface based on a measurement value of the film thickness measuring device, and a second polishing at a second predetermined temperature different from the first predetermined temperature, in which the substrate is polished while controlling a polishing load for pressing the substrate against the polishing surface based on a measurement value of the film thickness measuring device. The control device switches from the first polishing to the second polishing when the amount of the remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount. In one aspect, the predetermined temperature is a first predetermined temperature, and the polishing of the substrate includes a first polishing in which the substrate is polished at the first predetermined temperature while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of the film thickness measuring device, and a second polishing in which the substrate is polished at a second predetermined temperature that gradually changes from the first predetermined temperature while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of the film thickness measuring device. The control device switches from the first polishing to the second polishing when the amount of the remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount.

Advantages of the Invention

[0017] According to the present invention, since the polishing pad is maintained at a predetermined temperature during the polishing of the substrate, it is possible to polish the substrate at a desired polishing rate based on the measurement value of the film thickness measuring device. As a result, the substrate can be polished with an accurate film thickness profile.

Brief Description of the Drawings

[0018]

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[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a polishing apparatus (CMP apparatus) according to an embodiment. As shown in FIG. 1, the polishing apparatus 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 (slurry) to the surface of the polishing pad 3, and a pad temperature adjustment device 5 for adjusting the temperature of the polishing surface 3a of the polishing pad 3. The surface (upper surface) of the polishing pad 3 constitutes a polishing surface 3a for polishing the wafer W.

[0020] The polishing head 1 is movable in the vertical direction and rotatable about its axis in the direction indicated by the arrow. The wafer W is held on the lower surface of the polishing head 1 by vacuum suction or the like. A table motor 6 is connected to the polishing table 2 and is rotatable 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 attached to the upper surface of the polishing table 2.

[0021] The polishing apparatus includes a control device 40 that controls the operations of the polishing head 1, the table motor 6, the polishing liquid supply nozzle 4, and the pad temperature adjustment device 5. The control device 40 is composed of at least one computer. The control device 40 includes, for example, a storage device 110 in which a program is stored, and an arithmetic device 120 that performs arithmetic operations according to instructions included in the program. The arithmetic device 120 includes a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) that performs arithmetic operations according to instructions included in the program. The storage device 110 includes a main storage device (e.g., a random access memory) accessible by the arithmetic device 120 and an auxiliary storage device (e.g., a hard disk drive or a solid state drive) that stores data and programs.

[0022] The polishing apparatus further includes a film thickness sensor 7 that functions as a film thickness measuring device for measuring the film thickness of the wafer W. This film thickness sensor 7 is fixed to the polishing table 2 and rotates together with the polishing table 2. The film thickness sensor 7 is configured to generate a film thickness signal that changes according to the film thickness of the wafer W. The film thickness sensor 7 is installed inside the polishing table 2, and each time the polishing table 2 makes one rotation, it generates a film thickness signal indicating the film thickness of a plurality of regions including the central portion of the wafer W.

[0023] Examples of the film thickness sensor 7 include an optical sensor and an eddy current sensor. The eddy current sensor is a sensor that detects the magnetic flux linkage formed by the eddy current of the wafer W and detects the thickness of the wafer W based on the detected magnetic flux linkage. The optical sensor is a sensor that irradiates light onto the wafer W and detects the thickness of the wafer W by measuring the interference wave reflected from the wafer W.

[0024] During the polishing of the wafer W, the film thickness sensor 7 rotates together with the polishing table 2 and generates a film thickness signal while traversing the surface of the wafer W. This film thickness signal is an index value that directly or indirectly indicates the film thickness of the wafer W and changes according to the decrease in the film thickness of the wafer W. The film thickness sensor 7 is connected to the control device 40, and the film thickness signal is sent to the control device 40. When the film thickness of the wafer W indicated by the film thickness signal reaches a predetermined target thickness, the control device 40 issues commands to the polishing head 1 and the polishing table 2 to terminate the polishing of the wafer W.

[0025] FIG. 2 is a cross-sectional view showing the polishing head 1 shown in FIG. 1. The polishing head 1 includes a disk-shaped carrier 25, a circular flexible elastic membrane (membrane) 26 that forms a plurality of (four in this embodiment) pressure chambers D1, D2, D3, D4 below the carrier 25, and a retainer ring 28 that is arranged so as to surround the elastic membrane 26 and presses the polishing surface 3a of the polishing pad 3. The pressure chambers D1, D2, D3, D4 are formed between the elastic membrane 26 and the lower surface of the carrier 25. The carrier 25 of the polishing head 1 is fixed to the lower end of the head shaft.

[0026] The elastic membrane 26 has a plurality of annular partition walls 26a, and the pressure chambers D1, D2, D3, D4 are partitioned from each other by these partition walls 26a. The central pressure chamber D1 is circular, and the other pressure chambers D2, D3, D4 are annular. These pressure chambers D1, D2, D3, D4 are arranged concentrically. The number of pressure chambers is not particularly limited, and the polishing head 1 may be provided with more than four or less than four pressure chambers.

[0027] The pressure chambers D1, D2, D3, D4 are connected to fluid lines G1, G2, G3, G4, and pressurized fluid (e.g., pressurized air) is supplied into the pressure chambers D1, D2, D3, D4 through the fluid lines G1, G2, G3, G4. Pressure regulators R1, R2, R3, R4 are respectively attached to the fluid lines G1, G2, G3, G4. The pressure regulators R1, R2, R3, R4 can independently adjust the pressure of the pressurized fluid in the pressure chambers D1, D2, D3, D4. Thereby, the polishing head 1 can polish the corresponding four regions of the wafer W, namely, the central portion, the inner middle portion, the outer middle portion, and the peripheral portion, with the same or different polishing loads.

[0028] An annular elastic membrane 29 is disposed between the retainer ring 28 and the carrier 25. An annular pressure chamber D5 is formed inside this elastic membrane 29. This pressure chamber D5 is connected to a fluid line G5, and pressurized fluid (e.g., pressurized air) is supplied into the pressure chamber D5 through the fluid line G5. A pressure regulator R5 is attached to the fluid line G5. The pressure of the pressurized fluid in the pressure chamber D5 is adjusted by the pressure regulator R5. The pressure in the pressure chamber D5 is applied to the retainer ring 28, and the retainer ring 28 can directly press the polishing surface 3a of the polishing pad 3 independently of the elastic membrane (membrane) 26. Flow meters K1, K2, K3, K4, K5 are respectively attached to the fluid lines G1, G2, G3, G4, G5.

[0029] During the polishing of the wafer W, the elastic film 26 presses the wafer W against the polishing surface 3a of the polishing pad 3, and the retainer ring 28 presses the polishing surface 3a of the polishing pad 3 around the wafer W. The control device 40 controls (or determines) the pressure of the pressurized fluid supplied to the pressure chambers D1, D2, D3, D4, D5 based on the film thickness signals indicating the film thicknesses of a plurality of regions sent from the film thickness sensor 7. With such a configuration, the pressing force (i.e., the polishing load) for pressing the wafer W against the polishing pad 3 can be adjusted for each region of the wafer W, so that the entire surface of the wafer W can be polished to a uniform film thickness.

[0030] In the embodiment shown in FIG. 1, the pad temperature adjustment device 5 includes a heat exchanger 11 that adjusts the temperature of the polishing surface 3a by performing heat exchange with the polishing pad 3, a fluid supply system 30 that supplies the heat exchanger 11 with the temperature-adjusted heating fluid and cooling fluid, and a lifting mechanism 20 connected to the heat exchanger 11. The heat exchanger 11 is located above the polishing table 2 and the polishing surface 3a of the polishing pad 3, and the bottom surface of the heat exchanger 11 faces the polishing surface 3a of the polishing pad 3. The lifting mechanism 20 is configured to raise and lower the heat exchanger 11. More specifically, the lifting mechanism 20 is configured to move the bottom surface of the heat exchanger 11 in a direction approaching the polishing surface 3a of the polishing pad 3 and in a direction away from the polishing surface 3a of the polishing pad 3. The lifting mechanism 20 includes an actuator (not shown) such as a motor or an air cylinder. The operation of the lifting mechanism 20 is controlled by the control device 40.

[0031] The fluid supply system 30 includes a heating fluid supply tank 31 as a heating fluid supply source that stores the temperature-adjusted heating fluid, a heating fluid supply pipe 32 and a heating fluid return pipe 33 that connect the heating fluid supply tank 31 and the heat exchanger 11. One end of the heating fluid supply pipe 32 and the heating fluid return pipe 33 is connected to the heating fluid supply tank 31, and the other end is connected to the heat exchanger 11.

[0032] The temperature-adjusted heating fluid is supplied from the heating fluid supply tank 31 to the heat exchanger 11 through the heating fluid supply pipe 32, flows through the heat exchanger 11, and then is returned from the heat exchanger 11 to the heating fluid supply tank 31 through the heating fluid return pipe 33. Thus, the heating fluid circulates between the heating fluid supply tank 31 and the heat exchanger 11. The heating fluid supply tank 31 has a heater (not shown), and the heating fluid is heated to a predetermined temperature by the heater.

[0033] The fluid supply system 30 further includes a first on-off valve 41 and a first flow control valve 42 attached to the heating fluid supply pipe 32. The first flow control valve 42 is disposed between the heat exchanger 11 and the first on-off valve 41. The first on-off valve 41 is a valve that does not have a flow rate adjustment function, while the first flow control valve 42 is a valve that has a flow rate adjustment function.

[0034] The fluid supply system 30 further includes a cooling fluid supply pipe 51 and a cooling fluid discharge pipe 52 connected to the heat exchanger 11. The cooling fluid supply pipe 51 is connected to a cooling fluid supply source (for example, a cold water supply source) provided in the factory where the polishing apparatus is installed. The cooling fluid is supplied to the heat exchanger 11 through the cooling fluid supply pipe 51, flows through the heat exchanger 11, and then is discharged from the heat exchanger 11 through the cooling fluid discharge pipe 52. In one embodiment, the cooling fluid that has flowed through the heat exchanger 11 may be returned to the cooling fluid supply source through the cooling fluid discharge pipe 52.

[0035] The fluid supply system 30 further includes a second on-off valve 55 and a second flow control valve 56 attached to the cooling fluid supply pipe 51. The second flow control valve 56 is disposed between the heat exchanger 11 and the second on-off valve 55. The second on-off valve 55 is a valve that does not have a flow rate adjustment function, while the second flow control valve 56 is a valve that has a flow rate adjustment function.

[0036] The first on-off valve 41, the first flow control valve 42, the second on-off valve 55, and the second flow control valve 56 are connected to the control device 40, and the operations of the first on-off valve 41, the first flow control valve 42, the second on-off valve 55, and the second flow control valve 56 are controlled by the control device 40.

[0037] The polishing apparatus further includes a pad temperature measuring device 39 that measures the temperature of the polishing surface 3a of the polishing pad 3 (hereinafter sometimes referred to as the pad surface temperature). The pad temperature measuring device 39 is connected to the control device 40. The control device 40 is configured to operate the first flow control valve 42 and the second flow control valve 56 based on the pad surface temperature measured by the pad temperature measuring device 39. The first on-off valve 41 and the second on-off valve 55 are normally open. As the pad temperature measuring device 39, a radiation thermometer that can non-contactedly measure the temperature of the polishing surface 3a of the polishing pad 3 can be used. The pad temperature measuring device 39 is disposed above the polishing surface 3a of the polishing pad 3.

[0038] The pad temperature measuring device 39 non-contactedly measures the pad surface temperature and sends the measured value to the control device 40. The pad temperature measuring device 39 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 acquires 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 thermography, thermopile, and infrared camera. When the pad temperature measuring device 39 is a temperature distribution measuring device, the pad temperature measuring device 39 is configured to measure the distribution of the surface temperature of the polishing pad 3 in a region including the center and the outer peripheral edge of the polishing pad 3 and extending in the radial direction of the polishing pad 3. In this specification, the temperature distribution (temperature profile) indicates the relationship between the pad surface temperature and the radial position on the wafer W.

[0039] The control device 40 controls the flow rates of the heating fluid and the cooling fluid by operating the first flow control valve 42 and the second flow control valve 56 based on the measured pad surface temperature so that the pad surface temperature is maintained at a preset target temperature. The first flow control valve 42 and the second flow control valve 56 operate according to a control signal from the control device 40 and adjust the flow rate of the heating fluid and the flow rate of the cooling fluid supplied to the heat exchanger 11. Heat exchange occurs between the heating fluid and the cooling fluid flowing through the heat exchanger 11 and the polishing pad 3, thereby changing the pad surface temperature.

[0040] By such feedback control, the temperature of the polishing surface 3a of the polishing pad 3 (i.e., the pad surface temperature) is maintained at a predetermined target temperature. As the above feedback control, PID control can be used. The target temperature of the polishing pad 3 is determined according to the type of the film constituting the surface of the wafer W or the polishing process. The determined target temperature is input in advance to the control device 40 and stored in the storage device 110.

[0041] In order to maintain the pad surface temperature at a predetermined target temperature, during the polishing of the wafer W, the heat exchanger 11 contacts the surface of the polishing pad 3 (i.e., the polishing surface 3a). In this specification, the mode in which the heat exchanger 11 contacts the polishing surface 3a of the polishing pad 3 includes not only the mode in which the heat exchanger 11 directly contacts the polishing surface 3a of the polishing pad 3 but also the mode in which the heat exchanger 11 contacts the polishing surface 3a of the polishing pad 3 with a polishing liquid (slurry) present between the heat exchanger 11 and the polishing surface 3a of the polishing pad 3. In any mode, heat exchange occurs between the heating fluid and the cooling fluid flowing through the heat exchanger 11 and the polishing pad 3, thereby controlling the pad surface temperature.

[0042] As the heating fluid supplied to the heat exchanger 11, a heating fluid such as hot water is used. The heating fluid is heated to, for example, about 80°C by a heater (not shown) in the heating fluid supply tank 31. When it is desired to more rapidly raise the surface temperature of the polishing pad 3, silicone oil may be used as the heating fluid. When silicone oil is used as the heating fluid, the silicone oil is heated to 100°C or higher (for example, about 120°C) by a heater in the heating fluid supply tank 31.

[0043] As the cooling fluid supplied to the heat exchanger 11, a cooling fluid such as cold water or silicone oil is used. When silicone oil is used as the cooling fluid, a chiller is connected to the cooling fluid supply pipe 51 as the cooling fluid supply source, and by cooling the silicone oil to 0°C or lower, the polishing pad 3 can be rapidly cooled. As the cold water, pure water can be used. In order to cool the pure water to generate cold water, a chiller may be used as the cooling fluid supply source. In this case, the cold water that has flowed through the heat exchanger 11 may be returned to the chiller through the cooling fluid discharge pipe 52.

[0044] The heating fluid supply pipe 32 and the cooling fluid supply pipe 51 are completely independent pipes. Therefore, the heating fluid and the cooling fluid are supplied to the heat exchanger 11 simultaneously without being mixed. The heating fluid return pipe 33 and the cooling fluid discharge pipe 52 are also completely independent pipes. Therefore, the heating fluid is returned to the heating fluid supply tank 31 without being mixed with the cooling fluid, and the cooling fluid is discharged without being mixed with the heating fluid or returned to the cooling fluid supply source.

[0045] Next, the heat exchanger 11 will be described with reference to FIG. 3. FIG. 3 is a horizontal cross-sectional view showing the heat exchanger 11 according to one embodiment. As shown in FIG. 3, the heat exchanger 11 includes a flow path structure 71 in which a heating flow path 61 and a cooling flow path 62 are formed inside. In the present embodiment, the whole of the heat exchanger 11 has a circular shape. The bottom surface of the heat exchanger 11 is flat and circular. The bottom surface of the heat exchanger 11 is composed of the bottom surface of the flow path structure 71. The flow path structure 71 is made of a material having excellent wear resistance and high thermal conductivity, such as a ceramic such as dense SiC.

[0046] The heating flow path 61 and the cooling flow path 62 extend adjacent to each other (side by side) and in a spiral shape. Further, the heating flow path 61 and the cooling flow path 62 have a point-symmetric shape and have the same length as each other. Each of the heating flow path 61 and the cooling flow path 62 is basically composed of a plurality of arc flow paths 64 having a constant curvature and a plurality of inclined flow paths 65 connecting these arc flow paths 64. Two adjacent arc flow paths 64 are connected by each inclined flow path 65.

[0047] According to such a configuration, the outermost peripheral portions of each of the heating flow path 61 and the cooling flow path 62 can be arranged at the outermost peripheral portion of the heat exchanger 11. That is, the entire bottom surface of the heat exchanger 11 is located below the heating flow path 61 and the cooling flow path 62, and the heating fluid and the cooling fluid can quickly heat and cool the polishing surface 3a of the polishing pad 3. The heat exchange between the heating fluid and the cooling fluid and the polishing pad 3 is performed in a state where slurry exists between the polishing surface 3a of the polishing pad 3 and the bottom surface of the heat exchanger 11. However, the shapes of the heating flow path 61 and the cooling flow path 62 are not limited to the embodiment shown in FIG. 2 and may have other shapes.

[0048] The heating fluid supply pipe 32 (see FIG. 1) is connected to the inlet 61a of the heating flow path 61, and the heating fluid return pipe 33 (see FIG. 1) is connected to the outlet 61b of the heating flow path 61. The cooling fluid supply pipe 51 (see FIG. 1) is connected to the inlet 62a of the cooling flow path 62, and the cooling fluid discharge pipe 52 (see FIG. 1) is connected to the outlet 62b of the cooling flow path 62. The inlets 61a and 62a of the heating flow path 61 and the cooling flow path 62 are located at the peripheral portion of the heat exchanger 11, and the outlets 61b and 62b of the heating flow path 61 and the cooling flow path 62 are located at the central portion of the heat exchanger 11. Therefore, the heating fluid and the cooling fluid flow spirally from the peripheral portion to the central portion of the heat exchanger 11. The heating flow path 61 and the cooling flow path 62 are completely separated, and the heating fluid and the cooling fluid are not mixed within the heat exchanger 11.

[0049] FIG. 4 is a plan view showing the positional relationship between the heat exchanger 11 and the polishing head 1 on the polishing pad 3. The heat exchanger 11 is circular when viewed from above, and the diameter of the heat exchanger 11 is smaller than the diameter of the polishing head 1. The distance from the rotation center O of the polishing pad 3 to the center P of the heat exchanger 11 is the same as the distance from the rotation center O of the polishing pad 3 to the center Q of the polishing head 1. Since the heating flow path 61 and the cooling flow path 62 are adjacent to each other, the heating flow path 61 and the cooling flow path 62 are arranged not only in the radial direction of the polishing pad 3 but also along the circumferential direction of the polishing pad 3. Therefore, while the polishing table 2 and the polishing pad 3 are rotating, the polishing pad 3 exchanges heat with both the heating fluid and the cooling fluid.

[0050] In a polishing apparatus having such a pad temperature adjusting device 5, the wafer W is polished as follows. The wafer W to be polished is held by the polishing head 1 and further rotated by the polishing head 1. The polishing table 2 is rotated by a table motor 6 together with the polishing pad 3. In this state, a polishing liquid (slurry) is supplied from the polishing liquid supply nozzle 4 to the polishing surface 3a of the polishing pad 3. Next, the heat exchanger 11 of the pad temperature adjusting device 5 is brought into contact with the polishing surface 3a of the polishing pad 3, and the temperature of the polishing surface 3a is adjusted and maintained at a predetermined temperature. Further, the surface of the wafer W is pressed against the polishing surface 3a of the polishing pad 3 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 slurry. The surface of the wafer W is planarized by the chemical action of the slurry and the mechanical action of the abrasive grains contained in the slurry.

[0051] FIG. 5(a) is a graph showing an example of the temperature change of the polishing surface 3a of the polishing pad 3 adjusted by the pad temperature adjusting device 5 during the polishing of the wafer W, and FIG. 5(b) is a graph showing the change in the film thickness of the wafer W. In FIG. 5(a), the vertical axis represents the temperature of the polishing surface 3a, and the horizontal axis represents the elapsed time. In FIG. 5(b), the vertical axis represents the film thickness of the wafer W, and the horizontal axis represents the elapsed time.

[0052] As shown in FIG. 5(a), in the present embodiment, the heat exchanger 11 is brought into contact with the polishing surface 3a of the polishing pad 3 at time Ta, and the polishing surface 3a is heated so that the temperature of the polishing surface 3a reaches a predetermined temperature T1. Time Ta corresponds to the time when the temperature adjustment of the polishing surface 3a using the pad temperature adjusting device 5 is started. In the present embodiment, the wafer W held by the polishing head 1 is pressed against the polishing surface 3a at time Ta. At this time, the pressure of the pressurized fluid supplied to the pressure chambers D1, D2, D3, D4, D5 (see FIG. 2) is set to an arbitrary value, and based on the measured value of the film thickness sensor (film thickness measuring device) 7, the polishing of the wafer W for controlling the polishing load for pressing the wafer W against the polishing surface 3a has not been started.

[0053] Next, the control device 40 determines whether or not the temperature of the polishing surface 3a has stabilized at a predetermined temperature T1 based on the measured value of the temperature of the polishing surface 3a sent from the pad temperature measuring device 39. For example, the control device 40 stores in advance an allowable value set for the predetermined temperature T1, and monitors whether or not the temperature of the polishing surface 3a stays within this allowable value during a predetermined elapsed time. The control device 40 determines the time point Tb when the temperature of the polishing surface 3a has been within the allowable value for a predetermined elapsed time as the stabilization time point.

[0054] In one embodiment, the control device 40 may press the wafer W held by the polishing head 1 against the polishing pad 3a of the polishing pad 3 at the time point Tb instead of the time point Ta.

[0055] Next, when the polishing time reaches the stabilization time point Tb, the control device 40 starts polishing the wafer W by controlling the polishing load for pressing the wafer W against the polishing surface 3a based on the measured value of the film thickness sensor (film thickness measuring device) 7. Even if frictional heat is generated between the wafer W and the polishing pad 3, after the time point Tb, the temperature of the polishing surface 3a of the polishing pad 3 is maintained at the predetermined temperature T1 by the pad temperature adjusting device 5. Therefore, since the polishing rate does not change depending on the polishing temperature, the wafer W can be polished at a desired polishing rate based on the measured value of the film thickness sensor 7. That is, as shown in FIG. 5(b), the film thickness decreases at a constant rate. As a result, the substrate can be polished with an accurate film thickness profile. When the wafer W is polished until the film thickness reaches the target film thickness M1, the control device 40 ends the polishing of the wafer W at that time point Tc.

[0056] According to the present embodiment, even if the film to be polished is a film having the turning point TP shown in FIG. 20(b), the polishing rate does not change during the polishing of the wafer W, so the throughput of the polishing apparatus does not decrease. On the contrary, by setting the predetermined temperature T1 to the polishing temperature of the turning point TP or in the vicinity of the polishing temperature, the wafer W can be polished at the maximum polishing rate. As a result, the throughput of the polishing apparatus can be improved.

[0057] In one embodiment, when the control device 40 does not reach the time point Tb even after a predetermined time TE has elapsed since the time point Ta, the control device 40 may start polishing the wafer W by controlling the polishing load for pressing the wafer W against the polishing surface 3a based on the measured value of the film thickness sensor 7. In this case, since there may be an abnormality in the components of the polishing device including the pad temperature adjustment device 5 and the pad temperature measuring device 39, and / or in the wafer W, the control device 40 may issue an alarm, and in addition to the alarm, may stop the polishing of the wafer W. The control device 40 stores the predetermined time TE in advance.

[0058] In one embodiment, when the control device 40 does not reach the time point Tb even after polishing a predetermined amount of the film, the control device 40 may start polishing the wafer W by controlling the polishing load for pressing the wafer W against the polishing surface 3a based on the measured value of the film thickness sensor 7. Also in this case, since there may be an abnormality in the components of the polishing device including the pad temperature adjustment device 5 and the pad temperature measuring device 39, and / or in the wafer W, the control device 40 may issue an alarm, and in addition to the alarm, may stop the polishing of the wafer W. The control device 40 stores the above-mentioned predetermined amount in advance.

[0059] When the film thickness sensor 7 is an eddy current sensor, depending on the type of the eddy current sensor, the measured value may be affected by the ambient temperature. Therefore, in the present embodiment, the control device 40 may correct the measured value of the eddy current sensor. For example, a relational expression or a table showing the relationship between the temperature and the measured value of the eddy current sensor is obtained in advance by experiments, and the measured value of the eddy current sensor is corrected using this relational expression or table.

[0060] In one embodiment, the control device 40 may start polishing the wafer W by controlling the polishing load that presses the wafer W against the polishing surface 3a based on the measured value of the film thickness sensor 7 immediately after the time point Td when the temperature of the polishing surface 3a of the polishing pad 3 first reaches the predetermined temperature T1. In this case, the polishing rate is not stable from the time point Td until the time point Tb is reached, but after the time point Tb, the polishing rate becomes stable. Therefore, finally, the substrate can be polished with an accurate film thickness profile. In one embodiment, the wafer W held by the polishing head 1 may be pressed against the polishing surface 3a of the polishing pad 3 at the time point Td instead of the time point Ta.

[0061] As described above, the polishing rate of the wafer W also depends on the temperature of the polishing surface 3a of the polishing pad 3. Therefore, in order to obtain a more accurate film thickness profile while suppressing a decrease in throughput, the predetermined temperature T1 may be changed. In the following description of the embodiments described with reference to FIGS. 6(a) and 6(b), and in the following description of the embodiments described with reference to FIGS. 8(a) and 8(b), the predetermined temperature T1 is referred to as the "first predetermined temperature T1", and the polishing temperature of the polishing surface 3a changed from the first predetermined temperature is referred to as the "second predetermined temperature T2". In addition, since the configurations of these embodiments are the same as those of the embodiment described with reference to FIGS. 5(a) and 5(b) unless otherwise specified, the overlapping description is omitted.

[0062] FIG. 6(a) is a graph showing another example of the temperature change of the polishing surface 3a of the polishing pad 3 adjusted by the pad temperature adjusting device 5 during the polishing of the wafer W, and FIG. 6(b) is a graph showing the change in the film thickness of the wafer W. In FIG. 6(a), the vertical axis represents the temperature of the polishing surface 3a, and the horizontal axis represents the elapsed time. In FIG. 6(b), the vertical axis represents the film thickness of the wafer W, and the horizontal axis represents the elapsed time.

[0063] As shown in FIGS. 6(a) and 6(b), when the film thickness of the wafer W reaches the temperature-switching film thickness M2, the control device 40 switches the first predetermined temperature T1 to the second predetermined temperature T2. In the present embodiment, the second predetermined temperature T2 is lower than the first predetermined temperature T1, and the polishing rate at the second predetermined temperature T2 is lower than the polishing rate at the first predetermined temperature.

[0064] FIG. 7 is a schematic diagram for explaining the temperature-switching film thickness M2. FIG. 7 schematically depicts a cross-section of the wafer W that is the object to be polished. As shown in FIG. 7, the temperature-switching film thickness M2 is set in the vicinity of the target film thickness M1.

[0065] In the present embodiment, the control device 40 adjusts and maintains the temperature of the polishing surface 3a at the first predetermined temperature T1 at which a high polishing rate (for example, the maximum polishing rate) is achieved until the temperature-switching film thickness M2 is reached, and polishes the wafer W. When the film thickness reaches the temperature-switching film thickness M2, the control device 40 changes the temperature of the polishing surface 3a to the second predetermined temperature T2 at which the polishing rate is lower than the polishing rate at the first predetermined temperature T1. At the second predetermined temperature T2, the polishing of the wafer W proceeds slowly, so that a more accurate film thickness profile can be obtained. On the other hand, until the temperature-switching film thickness M2 is reached, the temperature of the polishing surface 3a is maintained at the first predetermined temperature T1 at which a high polishing rate is achieved, so that a decrease in throughput is suppressed.

[0066] In the example shown in FIGS. 6(a) and 6(b), the second predetermined temperature T2 is lower than the first predetermined temperature T1. However, depending on the type of film of the wafer W, the properties of the slurry, and / or the polishing conditions (for example, the rotation speed of the polishing head 1 and the rotation speed of the polishing table 2, etc.), the polishing rate may decrease by increasing the temperature of the polishing surface 3a. For example, when the film to be polished is a film having a turning point TP shown in FIG. 20(b), the polishing rate can be decreased by setting the temperature of the polishing surface 3a higher than the polishing temperature at the turning point TP. In such a case, the second predetermined temperature T2 may be set higher than the first predetermined temperature T1.

[0067] In the present embodiment, the second predetermined temperature T2 and the temperature switching film thickness M2 are preferably set in consideration of the type of film to be polished, polishing conditions (for example, the rotation speeds of the polishing head 1 and the polishing table 2, and the type of slurry), and the throughput of the polishing apparatus. For example, when it is desired to suppress a decrease in the throughput of the polishing apparatus, the temperature switching film thickness M2 may be set to a value as close as possible to the target film thickness M1 while considering the type of film to be polished and the polishing conditions, or the second predetermined temperature T2 may be set to a temperature as high (or low) as possible.

[0068] FIG. 8(a) is a graph showing still another example of the temperature change of the polishing surface 3a of the polishing pad 3 adjusted by the pad temperature adjusting device 5 during the polishing of the wafer W, and FIG. 8(b) is a graph showing the change in the film thickness of the wafer W. In FIG. 8(a), the vertical axis represents the temperature of the polishing surface 3a, and the horizontal axis represents the elapsed time. In FIG. 8(b), the vertical axis represents the film thickness of the wafer W, and the horizontal axis represents the elapsed time.

[0069] Also in the embodiment shown in FIGS. 8(a) and 8(b), when the film thickness reaches the temperature switching film thickness M2, the control device 40 changes the temperature of the polishing surface 3a from the first predetermined temperature T1 to the second predetermined temperature T2 at which the polishing rate is lower than the polishing rate at the first predetermined temperature. In the present embodiment, the control device 40 gradually decreases the second predetermined temperature T2. By performing such control, since the polishing rate gradually decreases, it is possible to obtain a more accurate film thickness profile while suppressing a decrease in throughput. Similar to the embodiment described with reference to FIGS. 6(a) and 6(b), when the polishing rate decreases by increasing the temperature of the polishing surface 3a, the control device 40 gradually increases the second predetermined temperature T2.

[0070] Also in this embodiment, similar to the embodiment described with reference to FIGS. 5(a) and 5(b), the second predetermined temperature T2 and the temperature switching film thickness M2 are preferably set in consideration of the type of film to be polished, polishing conditions (e.g., the rotation speeds of the polishing head 1 and the polishing table 2, and the type of slurry), and the throughput of the polishing apparatus. Further, in this embodiment, the throughput of the polishing apparatus can be adjusted by adjusting the amount of change in the second predetermined temperature. For example, if the amount of change in the second predetermined temperature is set higher, the throughput of the polishing apparatus can be improved. On the other hand, if the amount of change in the second predetermined temperature is set lower, a more accurate film thickness profile can be obtained.

[0071] In the above-described embodiment, the pad temperature adjustment device 5 has a heat exchanger 11 that contacts the polishing surface 3a of the polishing pad 3 as a device for adjusting the temperature of the polishing surface 3a of the polishing pad 3 (i.e., a device that functions as a heating device and a cooling device for the polishing surface 3a). That is, the above-described pad temperature adjustment device 5 is a contact-type pad temperature adjustment device in which the heat exchanger 11 contacts the polishing surface 3a. However, the pad temperature adjustment device 5 may be a non-contact-type pad temperature adjustment device that does not have a component that contacts the polishing surface 3a.

[0072] FIG. 9 is a schematic plan view of a polishing apparatus (CMP apparatus) according to another embodiment. The polishing apparatus shown in FIG. 9 differs from the polishing apparatus shown in FIG. 1 only in the configuration of the pad temperature adjustment device. Therefore, the same or corresponding components are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0073] In this embodiment, the pad temperature adjustment device 5 is a non-contact-type pad temperature adjustment device disposed above the polishing surface 3a of the polishing pad 3. This pad temperature adjustment device 5 includes a heating device (infrared heater) 15 that extends parallel to the polishing surface 3a of the polishing pad 3.

[0074] The infrared heater 15 emits infrared rays (radiant heat) onto the polishing surface 3a of the polishing pad 3. In the present embodiment, the infrared heater 15 has a disk shape arranged parallel to the polishing pad 3 (i.e., in the horizontal direction), but the shape of the infrared heater 15 is not limited to the present embodiment. In one embodiment, the infrared heater 15 may have a rectangular shape extending in the radial direction of the polishing pad 3. In one embodiment, the infrared heater 15 may be configured to be swingable along the radial direction of the polishing pad 3.

[0075] FIG. 10 is a schematic diagram showing the infrared heater 15 shown in FIG. 9. As shown in FIG. 10, the infrared heater 15 is arranged above the polishing pad 3. More specifically, the infrared heater 15 is arranged at a height such that it does not adhere to the polishing liquid supplied onto the polishing surface 3a of the polishing pad 3 and can heat the polishing surface 3a. According to such an arrangement, none of the components of the pad temperature adjusting device 5 come into contact with the polishing pad 3. Therefore, it is possible to prevent contamination of the wafer W caused by contact between the components of the pad temperature adjusting device 5 and the polishing surface 3a of the polishing pad 3.

[0076] Furthermore, when any component of the pad temperature adjusting device 5 comes into contact with the polishing pad 3 (the polishing surface 3a thereof), the polishing liquid will inevitably adhere (or stick) to this component. In this case, the adhered polishing liquid may fall onto the polishing surface 3a of the polishing pad 3 as foreign matter, and as a result, there is a risk that defects such as scratches may occur on the wafer W. According to the configuration of the present embodiment, since none of the components of the pad temperature adjusting device 5 come into contact with the polishing pad 3, defects such as scratches do not occur on the wafer W due to foreign matter falling from the components of the pad temperature adjusting device 5.

[0077] As shown in FIG. 9, the pad temperature adjustment device 5 may include a cooling device 17 that cools the polishing surface 3a of the polishing pad 3. As an example of the cooling device 17, a cooling device that injects gas onto the polishing surface 3a for cooling can be mentioned. As shown in FIG. 9, the cooling device 17 is connected to the control device 11, and the control device 11 can control the cooling device 17 independently of the infrared heater 15. With such a configuration, the control device 11 can adjust the temperature of the polishing surface 3a with higher accuracy.

[0078] In one embodiment, the pad temperature adjustment device 5 may include a plurality of heating devices. FIG. 11 is a diagram showing a plurality of infrared heaters 15A, 15B, and 15C arranged in the radial direction of the polishing pad 3. The pad temperature adjustment device 5 shown in FIG. 11 includes a plurality (three in this embodiment) of infrared heaters 15A, 15B, and 15C arranged in series in the radial direction of the polishing pad 3. Note that the number of infrared heaters is not limited to this embodiment. Two infrared heaters may be provided, or four or more infrared heaters may be provided.

[0079] Each of the plurality of infrared heaters 15A, 15B, and 15C is connected to the control device 11. The control device 11 can individually control each infrared heater 15A, 15B, and 15C, and can partially change the surface temperature of the polishing pad 3. In one embodiment, each infrared heater 15A, 15B, and 15C may be configured to be swingable along the radial direction of the polishing pad 3.

[0080] FIG. 12 is a diagram showing a pad temperature adjustment device provided with a reflector. As shown in FIG. 12, the pad temperature adjustment device 5 may include a reflector 16 that reflects the infrared rays radiated from the infrared heater 15 toward the polishing pad 3. The reflector 16 is disposed above the infrared heater 15 so as to cover the infrared heater 15. The reflector 16 can efficiently reflect the infrared rays radiated from the infrared heater 15 to the polishing surface 3a of the polishing pad 3 by the reflection. In one embodiment, the reflector 16 may be disposed not only above the infrared heater 15 but also on the side of the infrared heater 15.

[0081] FIGS. 13 and 14 are diagrams showing a pad temperature adjusting device provided with a suction nozzle. As shown in FIGS. 13 and 14, the pad temperature adjusting device 5 may include a suction nozzle 75 that lowers the ambient temperature by sucking hot air near the polishing surface 3a of the polishing pad 3 heated by the infrared heater 15. The suction nozzle 75 sucks the air above the polishing surface 3a adjacent to the polishing surface 3a to lower the temperature of the polishing surface 3a.

[0082] The suction nozzle 75 is connected to a suction device 76. More specifically, the suction port 75a of the suction nozzle 75 is disposed above the polishing surface 3a, and the connection end 75b of the suction nozzle 75 is connected to the suction device 76 via a suction line 74. A control valve 78 is connected to the suction line 74. These suction nozzle 75, suction line 74, control valve 78, and suction device 76 constitute a suction mechanism 70. The pad temperature adjusting device 5 includes the suction mechanism 70.

[0083] The suction port 75a of the suction nozzle 75 is disposed at a height capable of sucking the heat of the polishing surface 3a without sucking the polishing liquid supplied onto the polishing surface 3a of the polishing pad 3. In the embodiment shown in FIG. 13, the suction port 75a of the suction nozzle 75 is disposed at the center of the infrared heater 15. However, the arrangement location of the suction port 75a is not limited to the embodiment shown in FIG. 13.

[0084] FIG. 15 is a diagram showing still another embodiment of the pad temperature adjusting device. The configuration and operation of this embodiment not specifically described are the same as those of the above-described embodiment, and thus the overlapping description is omitted. As shown in FIG. 15, the pad temperature adjusting device 5 may include a fan 79 that is disposed adjacent to the infrared heater 15 and forms an air flow (see the arrow in FIG. 15) toward the polishing surface 3a of the polishing pad 3.

[0085] In the embodiment shown in FIG. 15, the fan 79 is disposed above the infrared heater 15 and is disposed to face the polishing surface 3a of the polishing pad 3 via the infrared heater 15. In one embodiment, the fan 79 may be disposed below the infrared heater 15.

[0086] The fan 79 is connected to the control device 40, and the control device 40 can drive the fan 79. When the fan 79 is driven with the infrared heater 15 being driven, the air around the fan 79 is sent as hot air to the polishing surface 3a of the polishing pad 3. The control device 40 controls the flow rate of the air (i.e., the wind speed) sent by the fan 79 to a flow rate at which the polishing liquid on the polishing pad 3 does not scatter. In the embodiment shown in FIG. 15, a single fan 79 is provided, but the number of fans 79 is not limited to this embodiment. A plurality of fans 79 may be provided.

[0087] The control device 40 can control the infrared heater 15 and the fan 79 separately. Therefore, in one embodiment, the control device 40 may drive only the fan 79 without driving the infrared heater 15 based on the temperature of the polishing surface 3a of the polishing pad 3 measured by the pad temperature measuring device 39. As a result, the polishing surface 3a of the polishing pad 3 is cooled by the air sent by the rotation of the fan 79.

[0088] FIGS. 16 and 17 are diagrams showing still other embodiments of the pad temperature adjusting device. The configuration and operation of this embodiment not specifically described are the same as those of the above-described embodiment, and thus the overlapping description is omitted.

[0089] In the embodiments shown in FIGS. 16 and 17, the pad temperature adjusting device 5 does not include the infrared heater 15. Instead, it includes a heating fluid nozzle 80 that sprays a heating fluid onto the polishing surface 3a of the polishing pad 3.

[0090] The pad temperature adjustment device 5 may include a suction nozzle 75 that sucks the heating fluid supplied from the heating fluid nozzle 80. The suction nozzle 75 has the same configuration as the suction nozzle 75 according to the embodiment shown in FIG. 13. Therefore, the description of the configuration of the suction nozzle 75 is omitted.

[0091] As shown in FIGS. 16 and 17, the heating fluid nozzle 80 includes a plurality of supply ports 80a arranged around the suction port 75a of the suction nozzle 75 so that the heating fluid flows toward the suction port 75a of the suction nozzle 75.

[0092] As shown in FIG. 17, the heating fluid nozzle 80 is connected to a heating fluid supply source 82. More specifically, the supply port 80a of the heating fluid nozzle 80 is disposed above the polishing surface 3a, and the connection end 80b of the heating fluid nozzle 80 is connected to the heating fluid supply source 82 via a supply line 81. A control valve 83 is connected to the supply line 81. The heating fluid nozzle 80, the supply line 81, the heating fluid supply source 82, and the control valve 83 constitute a heating mechanism 60. The pad temperature adjustment device 5 includes the heating mechanism 60.

[0093] The control device 40 is connected to the control valve 83. When the control device 40 opens the control valve 83, the heating fluid is supplied from the supply port 80a of the heating fluid nozzle 80 toward the polishing surface 3a of the polishing pad 3 through the supply line 81. Examples of the heating fluid include heated gas, heating steam, and superheated steam. Examples of the heated gas include high-temperature air (i.e., hot air). Superheated steam means high-temperature steam obtained by further heating saturated steam.

[0094] In the embodiment shown in FIG. 17, the three supply ports 80a are arranged at equal intervals so as to surround the suction port 75a of the suction nozzle 75, but the number of the supply ports 80a is not limited to this embodiment. The number of the supply ports 80a may be two, or may be four or more. The plurality of supply ports 80a may be arranged at unequal intervals so as to surround the suction port 75a.

[0095] As shown in FIGS. 16 and 17, the pad temperature adjustment device 5 may include a heat insulating cover 85 that covers the suction port 75a of the suction nozzle 75 and the supply port 80a of the heating fluid nozzle 80.

[0096] FIG. 18 is a diagram showing a modified example of the heating fluid nozzle 80 according to the embodiment shown in FIG. 16. Each supply port 80a may be inclined at an angle such that the polishing liquid on the polishing pad 3 does not scatter. In one embodiment, as shown in FIG. 18, a plurality (three in this embodiment) of supply ports 80a are inclined at a predetermined angle toward the suction port 75a of the suction nozzle 75 so that a swirling flow (see the arc-shaped arrow in FIG. 18) of the heating fluid toward the suction port 75a of the suction nozzle 75 is formed. In the embodiment shown in FIG. 18, each supply port 80a extends along the circumferential direction of the heat insulating cover 85 and is inclined at a predetermined angle toward the suction port 75a.

[0097] FIG. 19 is a diagram showing still another embodiment of the pad temperature adjustment device. As shown in FIG. 19, the embodiment shown in FIG. 13 and the embodiment shown in FIG. 16 may be combined. In the embodiment shown in FIG. 19, a reflecting plate 16 is attached to the inner surface of the heat insulating cover 85. Note that the embodiment shown in FIG. 10 (i.e., the embodiment in which the reflecting plate 16 is not provided) and the embodiment shown in FIG. 16 may be combined.

[0098] The surface temperature of the polishing pad 3 can be changed based on the configuration described in the above-described embodiments. For example, by adopting at least one of means for changing the magnitude of the current supplied to the infrared heater 15, means for changing the angle of the reflecting plate 16, means for changing the distance between the infrared heater 15 and the polishing surface 3a of the polishing pad 3, means for changing the rotation speed of the fan 79, and means for changing the angle at which the heating fluid is applied to the polishing surface 3a of the polishing pad 3, the control device 40 can change the surface temperature of the polishing pad 3.

[0099] When changing the angle of the reflector 16, the control device 40 may control the operation of a motor (not shown) capable of changing the angle of the reflector 16. When changing the distance between the infrared heater 15 and the polishing surface 3a of the polishing pad 3, the control device 40 may control the operation of a motor (not shown) capable of adjusting the height of the infrared heater 15. When changing the angle at which the heating fluid is applied to the polishing surface 3a, the control device 40 may control the operation of a motor (not shown) capable of changing the angle of the heating fluid nozzle 80.

[0100] In the embodiment shown in FIG. 11, an example of partially changing the surface temperature of the polishing pad 3 has been described. However, the surface temperature of the polishing pad 3 may be partially changed by the means described below. For example, by adopting at least one of the means of changing the angle of the reflector 16, changing the orientation angle of the infrared heater 15, and changing the angle at which the heating fluid is applied, the control device 40 can partially change the temperature of the polishing surface 3a of the polishing pad 3.

[0101] The above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to practice the present invention. Various modifications of the above embodiments can be naturally made by those skilled in the art, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is construed in the broadest scope in accordance with the technical idea defined by the claims.

Explanation of Reference Numerals

[0102] 1 Polishing head 2 Polishing table 3 Polishing pad 4 Polishing liquid supply nozzle 5 Pad temperature adjustment device 6 Table motor 11 Heat exchanger 15 Heating device (infrared heater) 15A, 15B, 15C Infrared heaters 16 Reflector 17 Cooling device 25 Suction nozzle 26 Elastic membrane 30 Fluid supply system 39 Pad temperature measurer 40 Control device 60 Heating mechanism 70 Suction mechanism 79 Fan 80 Heating fluid nozzle

Claims

1. Adjust the temperature of the polishing surface of the polishing pad to a predetermined temperature using a pad temperature adjustment device, while polishing the substrate while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of a film thickness measuring device provided on the polishing pad, wherein the predetermined temperature is a first predetermined temperature, the step of polishing the substrate is a first polishing for polishing the substrate while controlling the polishing load for pressing the substrate against the polishing surface such that the measurement value of the film thickness measuring device decreases at a constant rate at the first predetermined temperature, a second polishing for polishing the substrate while controlling the polishing load for pressing the substrate against the polishing surface such that the measurement value of the film thickness measuring device decreases at a constant rate at a second predetermined temperature different from the first predetermined temperature, the switching from the first polishing to the second polishing is performed when the amount of the remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount, the step of polishing the substrate starts immediately after the temperature of the polishing surface reaches the first predetermined temperature, a polishing method.

2. The step of polishing the substrate is performed while maintaining the temperature of the polishing surface at the first predetermined temperature or the second predetermined temperature, the polishing method according to Claim 1.

3. Adjust the temperature of the polishing surface of the polishing pad to a predetermined temperature using a pad temperature adjustment device, while polishing the substrate while controlling the polishing load for pressing the substrate against the polishing surface based on the measurement value of a film thickness measuring device provided on the polishing pad, wherein the predetermined temperature is a first predetermined temperature, the step of polishing the substrate is a first polishing for polishing the substrate while controlling the polishing load for pressing the substrate against the polishing surface such that the measurement value of the film thickness measuring device decreases at a constant rate at the first predetermined temperature, a second polishing for polishing the substrate while controlling the polishing load for pressing the substrate against the polishing surface such that the measurement value of the film thickness measuring device decreases at a constant rate at a second predetermined temperature gradually changed from the first predetermined temperature, the switching from the first polishing to the second polishing is performed when the amount of the remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount, a polishing method.

4. a polishing table for supporting the polishing pad, a polishing head for pressing the 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 adjustment device for adjusting the temperature of the polishing surface; A film thickness measuring device attached to the polishing table; A control device for controlling the operations of at least the polishing head and the pad temperature adjustment device, and; The control device: Based on the measured value of the pad temperature measuring device, adjusts the temperature of the polishing surface to a predetermined temperature using the pad temperature adjustment device; Based on the measured value of the film thickness measuring device, polishes the substrate while controlling the polishing load for pressing the substrate against the polishing surface; The predetermined temperature is a first predetermined temperature; The polishing of the substrate: A first polishing in which the substrate is polished while controlling the polishing load for pressing the substrate against the polishing surface so that the measured value of the film thickness measuring device decreases at a constant rate at the first predetermined temperature; A second polishing in which the substrate is polished while controlling the polishing load for pressing the substrate against the polishing surface so that the measured value of the film thickness measuring device decreases at a constant rate at a second predetermined temperature different from the first predetermined temperature, and; The control device switches from the first polishing to the second polishing when the amount of the remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount; The control device starts polishing the substrate immediately after the temperature of the polishing surface reaches the first predetermined temperature, a polishing device.

5. The control device polishes the substrate while maintaining the temperature of the polishing surface at the first predetermined temperature or the second predetermined temperature, the polishing device according to claim 4.

6. 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 adjustment device for adjusting the temperature of the polishing surface; A film thickness measuring device attached to the polishing table; A control device for controlling the operations of at least the polishing head and the pad temperature adjustment device, and; The control device: Based on the measured value of the pad temperature measuring device, adjusts the temperature of the polishing surface to a predetermined temperature using the pad temperature adjustment device; Based on the measured value of the film thickness measuring device, polishes the substrate while controlling the polishing load for pressing the substrate against the polishing surface; The predetermined temperature is a first predetermined temperature; The polishing of the substrate: A first polishing in which the substrate is polished while controlling the polishing load for pressing the substrate against the polishing surface so that the measured value of the film thickness measuring device decreases at a constant rate at the first predetermined temperature; A second polishing step of polishing the substrate while controlling a polishing load for pressing the substrate against the polishing surface such that a measurement value of the film thickness measuring device decreases at a constant rate at a second predetermined temperature that gradually changes from the first predetermined temperature, The polishing apparatus, wherein the control device switches from the first polishing step to the second polishing step when an amount of a remaining film of the substrate measured by the film thickness measuring device reaches a predetermined amount.

Images