JP6849506B2 - A computer-readable recording medium on which board holding devices, board processing devices, board processing methods, and programs are recorded. - Google Patents

Description

The present invention relates to a substrate holding device that holds a substrate to which a liquid is supplied by vacuum adsorption. The present invention also relates to a substrate processing apparatus and a substrate processing method for processing a substrate held by such a substrate holding apparatus. Furthermore, the present invention relates to a computer-readable recording medium on which a program for executing such a substrate processing method is recorded.

From the viewpoint of improving the yield in the manufacture of semiconductor devices, the control of the surface state of the substrate has been attracting attention in recent years. In the process of manufacturing a semiconductor device, various materials are formed on a silicon wafer. Therefore, an unnecessary film or surface roughness is formed on the peripheral edge of the substrate. In recent years, a method of transporting a substrate by holding only the peripheral edge of the substrate with an arm has become common. Under such a background, the unnecessary film remaining on the peripheral edge is peeled off during various steps and adheres to the device formed on the substrate, which reduces the yield. Therefore, in order to remove an unnecessary film formed on the peripheral edge of the substrate, the peripheral edge of the substrate is polished using a polishing device. The polishing device for polishing the peripheral edge of the substrate is, for example, supplying a polishing liquid onto the substrate held by the substrate holding device and sliding a polishing tool such as a polishing tape on the peripheral edge of the substrate. As a result, the peripheral edge of the substrate is polished.

In addition, as semiconductor devices become more integrated and denser, circuit wiring is becoming finer and the number of layers of multi-layer wiring is increasing. A polishing device that polishes the surface of a substrate on which a semiconductor device is formed is used in order to realize multi-layer wiring while miniaturizing a circuit. The polishing device that polishes the surface of the substrate polishes the surface of the substrate held by the substrate holding device while supplying a polishing liquid containing abrasive grains such as _{silica (SiO 2) onto the polishing surface of the polishing pad.} Make it slide on the surface. As a result, the surface of the substrate is polished.

Further, the manufacturing process of the semiconductor device includes various substrate treatments such as plating treatment, etching treatment, and polishing treatment. In the process of performing these substrate treatments, particles may adhere to the surface of the substrate. Particles on the surface of the substrate can cause device defects such as short circuits in the wiring. Therefore, a cleaning device is used to remove particles from the surface of the substrate. The cleaning device cleans the surface of the substrate by bringing the liquid into contact with the surface of the substrate held by the substrate holding device, for example.

The polishing device and the cleaning device are substrate processing devices that perform substrate processing such as polishing or cleaning while rotating the substrate held by the substrate holding device. The substrate holding device provided in such a substrate processing device generally drives a substrate holding portion that holds the substrate by vacuum suction, a rotating shaft connected to the substrate holding portion, and a motor that rotates the rotating shaft. It includes a source and a control unit that controls the operation of components such as a substrate holding unit, a rotating shaft, and a drive source. The substrate holding portion has a substrate holding surface that holds the substrate by vacuum suction. The control unit of the substrate processing apparatus may be used as the control unit of the substrate holding apparatus.

Further, in order to evacuate the substrate to the substrate holding surface, the substrate holding device has a vacuum line for communicating the substrate holding surface with the vacuum source and a vacuum source valve arranged on the vacuum line. The vacuum main valve is connected to the control unit. When the control unit opens the vacuum source valve, the substrate holding surface communicates with the vacuum source, and the substrate placed on the substrate holding surface is evacuated. When a liquid (for example, polishing liquid, cleaning liquid, etc.) is supplied to the substrate vacuum-adsorbed on the substrate holding surface, a gas-liquid two-phase flow composed of the liquid and the atmosphere causes a slight gap between the substrate and the substrate holding surface. It penetrates into the vacuum line and is sucked into the vacuum line. As a result, the vacuum source is contaminated by the liquid contained in the gas-liquid two-phase flow.

Therefore, the substrate holding device further has a gas-liquid separation unit provided with a gas-liquid separation tank. The gas-liquid separation tank of the gas-liquid separation unit is arranged in a vacuum line, and the liquid is separated from the gas-liquid two-phase flow sucked into the vacuum line from the substrate holding surface by the gas-liquid separation tank. Further, the gas-liquid separation unit includes a discharge line for discharging the liquid accumulated in the gas-liquid separation tank, a drain valve arranged in the discharge line, and a liquid level sensor capable of detecting the liquid level in the gas-liquid separation tank. Have. The drain valve and the liquid level sensor are connected to the control unit. When the control unit closes the vacuum main valve and opens the drain valve arranged in the discharge line, the liquid accumulated in the gas-liquid separation tank is discharged from the gas-liquid separation tank via the discharge line.

The liquid level sensor of the conventional gas-liquid separation unit functions as a full liquid sensor for preventing the liquid from overflowing from the gas-liquid separation tank. That is, the control unit monitors the upper limit of the liquid level in the gas-liquid separation tank by the signal output from the liquid level sensor. When the control unit receives the signal output from the liquid level sensor, the control unit stops the substrate processing in the substrate processing apparatus in order to prevent the liquid from overflowing from the gas-liquid separation tank. In this case, it is possible to prevent the liquid from overflowing from the gas-liquid separation tank, but the substrate being processed is discarded. Therefore, the control unit opens the drain valve for a predetermined time each time the substrate is processed so that the liquid level in the gas-liquid separation tank does not reach the liquid level detection position of the liquid level sensor, and the liquid is discharged from the gas-liquid separation tank. Perform a drainage process to drain.

Japanese Unexamined Patent Publication No. 2015-150648

However, since the vacuum source valve is closed during the drainage treatment for discharging the liquid from the gas-liquid separation tank, the substrate cannot be vacuum-adsorbed to the substrate holding surface. That is, the substrate process cannot be executed during the drainage process.

In the conventional substrate holding device, since the drainage treatment is executed every time the substrate is processed, wasted time is generated between the completion of the substrate processing and the start of the substrate processing of the next substrate. There is a risk. More specifically, even when the liquid level in the gas-liquid separation tank that rises due to the next substrate processing does not reach the liquid level detection position of the liquid level sensor, that is, the substrate processing device does not perform the drainage treatment. Even if does not stop, the control unit executes the drainage process. In this case, the time between the drainage treatments is wasted, which hinders the improvement of the throughput of the substrate processing.

Further, since the conventional substrate holding device has only one liquid level sensor that functions as a full liquid sensor, the control unit ensures that the liquid is discharged from the gas-liquid separation tank when the drain valve is opened. It cannot be monitored whether or not it is present. For example, if the discharge line is clogged, the liquid cannot be discharged from the gas-liquid separation tank even if the drain valve is opened. In this case, even if the control unit opens the drain valve for each substrate processing for a predetermined time, the liquid level in the gas-liquid separation tank rises to the liquid level detection position of the liquid level sensor, and the substrate processing is stopped.

Therefore, an object of the present invention is to provide a substrate holding device capable of improving the throughput of substrate processing while monitoring that the drainage treatment for discharging the liquid from the gas-liquid separation tank is surely executed. And. Another object of the present invention is to provide a substrate processing apparatus and a substrate processing method provided with such a substrate holding device. Furthermore, it is an object of the present invention to provide a computer-readable recording medium on which a program for executing such a substrate processing method is recorded.

In order to achieve the above-mentioned object, one aspect of the present invention is a substrate holding portion having a substrate holding surface for holding a substrate to which a liquid is supplied by vacuum adsorption, and a vacuum line for communicating the substrate holding surface with a vacuum source. And at least one gas-liquid separation unit that separates the liquid from the gas-liquid two-phase flow sucked into the vacuum line from the substrate holding surface, and a control unit that controls the operation of the substrate holding unit and the gas-liquid separation unit. The gas-liquid separation unit includes a gas-liquid separation tank arranged in the vacuum line, a discharge line for discharging the liquid accumulated in the gas-liquid separation tank, and a drain valve arranged in the discharge line. , A high liquid level sensor capable of detecting the liquid level of the gas-liquid separation tank, a low liquid level sensor capable of detecting the liquid level of the gas-liquid separation tank lower than the high liquid level sensor, and the gas-liquid separation tank. A liquid level detection pipe connected to the above and where the high liquid level sensor and the low liquid level sensor are arranged, an extrusion line connected to the gas-liquid separation tank, and the liquid level detection pipe branched from the extrusion line. The control unit controls the opening / closing operation of the drain valve based on the output signal of the low liquid level sensor, and discharges the liquid accumulated in the gas-liquid separation tank to the discharge line. The substrate holding device is characterized in that the pressurized gas extruded into the gas-liquid separation tank is supplied to the gas-liquid separation tank via the extrusion line.

A preferred embodiment of the present invention is characterized in that the substrate holding device is further provided with a flow rate regulator arranged in the purge line and adjusting the flow rate of the pressurized gas flowing through the purge line.
In a preferred embodiment of the present invention, the at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit, and the first gas-liquid separation unit is detected by the high liquid level sensor. An intermediate liquid level sensor capable of detecting the liquid level between the liquid level and the liquid level detected by the low liquid level sensor is further provided, and the control unit receives an output signal from the intermediate liquid level sensor. In this case, the gas-liquid separation tank into which the gas-liquid two-phase flow is introduced is switched from the gas-liquid separation tank of the first gas-liquid separation unit to the gas-liquid separation tank of the second gas-liquid separation unit. And.

Another aspect of the present invention processes a substrate holding device that holds a substrate, a liquid supply unit that supplies a liquid to the substrate held by the substrate holding device, and the substrate held by the substrate holding device. A substrate processing unit, the substrate holding device, the liquid supply unit, and a control unit for controlling the operation of the substrate processing unit are provided, and the substrate holding device has a substrate holding surface for holding the substrate by vacuum suction. At least one gas-liquid separation unit that separates a liquid from a substrate holding portion, a vacuum line that communicates the substrate holding surface with a vacuum source, and a gas-liquid two-phase flow that flows from the substrate holding surface through the vacuum line. The gas-liquid separation unit is arranged in the gas-liquid separation tank arranged in the vacuum line, a discharge line for discharging the liquid accumulated in the gas-liquid separation tank, and the discharge line. A drain valve, a high liquid level sensor capable of detecting the liquid level of the gas-liquid separation tank, a low liquid level sensor capable of detecting the liquid level of the gas-liquid separation tank lower than the high liquid level sensor, and the above. The liquid level detection pipe connected to the gas-liquid separation tank and arranged with the high-liquid level sensor and the low-liquid level sensor, an extrusion line connected to the gas-liquid separation tank, and a branch from the extrusion line are described. It has a purge line connected to the liquid level detection pipe, and the control unit controls the opening / closing operation of the drain valve based on the output signal of the low liquid level sensor, and the gas-liquid separation tank has. The substrate processing apparatus is characterized in that a pressurized gas that pushes the accumulated liquid to the discharge line is supplied to the gas-liquid separation tank via the extrusion line.

In a preferred embodiment of the present invention, the at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit, and the first gas-liquid separation unit is detected by the high liquid level sensor. An intermediate liquid level sensor capable of detecting the liquid level between the liquid level and the liquid level detected by the low liquid level sensor is further provided, and the control unit receives an output signal from the intermediate liquid level sensor. In this case, the gas-liquid separation tank into which the gas-liquid two-phase flow is introduced is switched from the gas-liquid separation tank of the first gas-liquid separation unit to the gas-liquid separation tank of the second gas-liquid separation unit. And.

In still another aspect of the present invention, the substrate is held on the substrate holding surface by vacuum adsorption, the substrate is treated while supplying a liquid to the substrate, and a gas-liquid separation tank provided in at least one gas-liquid separation unit is provided. The liquid is separated from the gas-liquid two-phase flow sucked from the substrate holding surface, and the liquid level in the gas-liquid separation tank is set to a high liquid level arranged in the liquid level detection pipe connected to the gas-liquid separation tank. Only when the sensor and the low-liquid level sensor capable of detecting the liquid level lower than the high-liquid level sensor monitor and the signal is output from the low-liquid level sensor after the processing of the substrate is completed. Then, a drainage treatment for discharging the liquid from the gas-liquid separation tank is executed, and during the execution of the drainage treatment, the gas-liquid separation layer is pressurized via an extrusion line connected to the gas-liquid separation layer. A gas is supplied to push the liquid accumulated in the gas-liquid separation tank to the discharge line, and the pressurized gas is supplied to a purge line branched from the extrusion line and connected to the liquid level detection pipe. It is a substrate processing method characterized by.

In a preferred embodiment of the present invention, the at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit, and the liquid in the first gas-liquid separation tank is being processed during the processing of the substrate. The surface is monitored by an intermediate liquid level sensor capable of detecting the liquid level between the liquid level detected by the high liquid level sensor and the liquid level detected by the low liquid level sensor, and from the intermediate liquid level sensor. When a signal is output, the gas-liquid separation tank that separates the liquid from the gas-liquid two-phase flow is switched from the gas-liquid separation tank of the first gas-liquid separation unit to the gas-liquid separation tank of the second gas-liquid separation unit. It is characterized by that.

Yet another aspect of the present invention is provided in at least one gas-liquid separation unit, a step of holding the substrate on the substrate holding surface by vacuum adsorption, a step of processing the substrate while supplying a liquid to the substrate, and a step of processing the substrate. The step of separating the liquid from the gas-liquid two-phase flow sucked from the substrate holding surface in the gas-liquid separation tank and the liquid level in the gas-liquid separation tank are connected to the liquid level detection pipe connected to the gas-liquid separation tank. A signal from the low liquid level sensor after the step of monitoring by the arranged high liquid level sensor and the low liquid level sensor capable of detecting the liquid level lower than the high liquid level sensor and the processing of the substrate are completed. Is output only when the step of executing the drainage treatment for discharging the liquid from the gas-liquid separation tank and the extrusion line connected to the gas-liquid separation layer during the drainage treatment. A pressurized gas is supplied to the gas-liquid separation layer to push the liquid accumulated in the gas-liquid separation tank to the discharge line, and at the same time, to a purge line branched from the extrusion line and connected to the liquid level detection pipe. A non-temporary computer-readable recording medium on which a program for causing a computer to execute the step of supplying the pressurized gas is recorded.

In a preferred embodiment of the present invention, the at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit, and when the step of processing the substrate is being executed, the first gas-liquid separation unit is performed. The liquid level in the gas-liquid separation tank is monitored by an intermediate liquid level sensor capable of detecting the liquid level between the liquid level detected by the high liquid level sensor and the liquid level detected by the low liquid level sensor. The step and the gas-liquid separation tank that separates the liquid from the gas-liquid two-phase flow when a signal is output from the intermediate liquid level sensor are moved from the gas-liquid separation tank of the first gas-liquid separation unit to the second gas-liquid. It features a step of switching the separation unit to a gas-liquid separation tank, and the computer further performing.

According to the present invention, the control unit opens the drain valve and executes the drainage process of discharging the liquid from the gas-liquid separation tank only when the low liquid level sensor detects the liquid level. That is, since the control unit can execute the drainage treatment only when the drainage treatment is required, the throughput of the substrate processing can be improved. Further, the control unit can monitor that the drainage process is surely executed based on the signal output from the low liquid level sensor. As a result, the disposal of the substrate can be effectively prevented.

It is sectional drawing which shows the substrate processing apparatus which concerns on one Embodiment. It is a vertical sectional view of the substrate processing apparatus shown in FIG. 3 (a) and 3 (b) are enlarged cross-sectional views showing the peripheral edge of the substrate. It is an enlarged view of a polishing head. It is a figure which shows the state which the polishing head is polishing the bevel part of a substrate. It is a schematic diagram of the substrate holding apparatus provided in the polishing apparatus shown in FIG. 1 and FIG. It is a flowchart of the polishing process executed by the polishing apparatus shown in FIGS. 1 and 2. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which shows the substrate holding apparatus which concerns on other embodiment. It is a flowchart of the polishing process of the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which showed each process of polishing the wafer held in the substrate holding apparatus shown in FIG. It is a schematic diagram which shows an example of the structure of a control part. It is a schematic diagram which shows the substrate processing apparatus which concerns on other embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view showing a substrate processing apparatus according to an embodiment, and FIG. 2 is a vertical cross-sectional view of the substrate processing apparatus shown in FIG. The substrate processing apparatus shown in FIG. 1 is a polishing apparatus that polishes the bevel portion of the wafer W, which is an example of a substrate.

Here, in the present specification, the peripheral edge portion of the wafer W is defined as a region including a bevel portion located on the outermost periphery of the substrate and a top edge portion and a bottom edge portion located radially inside the bevel portion. .. 3A and 3B are enlarged cross-sectional views showing the peripheral edge of the wafer W. More specifically, FIG. 3A is a cross-sectional view of a so-called straight type wafer W, and FIG. 3B is a cross-sectional view of a so-called round type wafer W. In the wafer W of FIG. 3A, the bevel portion is a wafer W composed of an upper inclined portion (upper bevel portion) P, a lower inclined portion (lower bevel portion) Q, and a side portion (apex) R. It is the outermost peripheral surface (indicated by reference numeral B). In the wafer W of FIG. 3B, the bevel portion is a portion (indicated by reference numeral B) having a curved cross section, which constitutes the outermost peripheral surface of the wafer W. The top edge portion is a flat portion E1 located radially inside the bevel portion B. The bottom edge portion is a flat portion E2 located on the opposite side of the top edge portion and radially inside the bevel portion B. The top edge portion may also include an area in which the device is formed.

As shown in FIGS. 1 and 2, this polishing apparatus includes a substrate holding apparatus 3 that horizontally holds and rotates the wafer W. FIG. 1 shows a state in which the substrate holding device 3 holds the wafer W. In the present embodiment, the polishing device includes a control unit 9 that controls the operation of the entire polishing device including the substrate holding device 3. The substrate holding device 3 rotates a dish-shaped holding stage (board holding portion) 4 that holds the back surface of the wafer W by vacuum suction, a hollow shaft 5 connected to the central portion of the holding stage 4, and the hollow shaft 5. It is provided with a motor M1 for making the motor. The wafer W is placed on the substrate holding surface 4a of the holding stage 4 by a hand (not shown) of the transport mechanism so that the center of the wafer W coincides with the axis of the hollow shaft 5.

The hollow shaft 5 is supported by a ball spline bearing (linear motion bearing) 6 so as to be vertically movable. A groove 4b is formed on the substrate holding surface 4a of the holding stage 4, and the groove 4b communicates with the vacuum line L1 extending through the hollow shaft 5. The vacuum line L1 is connected to a vacuum source (not shown) via a rotary joint 8 attached to the lower end of the hollow shaft 5. A gas-liquid separation tank 16 is arranged in the vacuum line L1. A part of the vacuum line L1 extending from the gas-liquid separation tank 16 to the holding stage 4 functions as a vacuum primary line (communication line) L2 for communicating the internal space of the gas-liquid separation tank 16 with the substrate holding surface 4a. A part of the vacuum line L1 extending from the gas-liquid separation tank 16 to the vacuum source functions as a vacuum secondary line L3.

The gas-liquid separation tank 16 is connected to a gas supply line L4 for separating the processed wafer W from the substrate holding surface 4a of the holding stage 4. When the wafer W is vacuum-adsorbed to the substrate holding surface 4a, the control unit 9 communicates the substrate holding surface 4a with the vacuum source via the vacuum primary line L2, the gas-liquid separation tank 16, and the vacuum secondary line L3. On the other hand, when the processed wafer W is separated from the substrate holding surface 4a, the control unit 9 pressurizes the substrate holding surface 4a via the vacuum primary line L2, the gas-liquid separation tank 16, and the gas supply line L4. Supply gas. That is, by switching between the vacuum secondary line L3 and the gas supply line L4, the control unit 9 vacuum-adsorbs the wafer W to the substrate holding surface 4a of the holding stage 4 via the vacuum primary line L2 and detaches it. The substrate holding device 3 includes a vacuum line L1 having a vacuum primary line L2 and a vacuum secondary line L3, a gas-liquid separation tank 16, a holding stage 4 having a substrate holding surface 4a, and the like. The configuration and operation will be described later.

The hollow shaft 5 is rotated by the motor M1 via a pulley p1 connected to the hollow shaft 5, a pulley p2 attached to the rotating shaft of the motor M1, and a belt b1 hung on these pulleys p1 and p2. .. The rotation shaft of the motor M1 extends parallel to the hollow shaft 5. With such a configuration, the wafer W held on the substrate holding surface 4a of the holding stage 4 is rotated by the motor M1.

The ball spline bearing 6 is a bearing that allows the hollow shaft 5 to move freely in the longitudinal direction thereof. The ball spline bearing 6 is fixed to a cylindrical casing 12. Therefore, in the present embodiment, the hollow shaft 5 is configured to be able to linearly move up and down with respect to the casing 12, and the hollow shaft 5 and the casing 12 rotate integrally. The hollow shaft 5 is connected to an air cylinder (elevating mechanism) 15, and the hollow shaft 5 and the holding stage 4 can be raised and lowered by the air cylinder 15.

A radial bearing 18 is interposed between the casing 12 and the cylindrical casing 14 arranged concentrically on the outer side of the casing 12, and the casing 12 is rotatably supported by the bearing 18. With such a configuration, the substrate holding device 3 can rotate the wafer W around its central axis Cr and raise and lower the wafer W along the central axis Cr.

As shown in FIG. 1, four polishing head assemblies 1A, 1B, 1C, and 1D are arranged around the wafer W held by the substrate holding device 3. Each of the polishing head assemblies 1A, 1B, 1C, and 1D functions as a substrate processing unit for polishing the bevel portion of the wafer W. Polishing tape supply mechanisms 2A, 2B, 2C, and 2D are provided on the radial outer sides of the polishing head assemblies 1A, 1B, 1C, and 1D, respectively. The polishing head assembly 1A, 1B, 1C, 1D and the polishing tape supply mechanism 2A, 2B, 2C, 2D are separated by a partition wall 20. The internal space of the partition wall 20 constitutes the polishing chamber 21, and the four polishing head assemblies 1A, 1B, 1C, 1D and the holding stage 4 are arranged in the polishing chamber 21. On the other hand, the polishing tape supply mechanisms 2A, 2B, 2C, and 2D are arranged outside the partition wall 20 (that is, outside the polishing chamber 21). The polishing head assemblies 1A, 1B, 1C, and 1D have the same configuration as each other, and the polishing tape supply mechanisms 2A, 2B, 2C, and 2D also have the same configuration as each other. Hereinafter, the polishing head assembly 1A and the polishing tape supply mechanism 2A will be described.

The polishing tape supply mechanism 2A includes a supply reel 24 for supplying the polishing tape 23, which is an example of a polishing tool, to the polishing head assembly 1A, and a recovery reel 25 for collecting the polishing tape 23 used for polishing the wafer W. ing. The supply reel 24 is arranged above the recovery reel 25. A motor M2 is connected to the supply reel 24 and the recovery reel 25 via a coupling 27, respectively (FIG. 1 shows only the coupling 27 and the motor M2 connected to the supply reel 24). Each motor M2 can apply a constant torque in a predetermined rotation direction to apply a predetermined tension to the polishing tape 23.

The polishing tape 23 is a long strip-shaped polishing tool, and one side thereof constitutes a polishing surface. The polishing tape 23 has a base material tape made of a PET sheet or the like, and a polishing layer formed on the base material tape. The polishing layer is composed of a binder (for example, resin) that covers one surface of the base material tape and abrasive grains held by the binder, and the surface of the polishing layer constitutes the polishing surface. As the polishing tool, a strip-shaped polishing cloth may be used instead of the polishing tape 23.

The polishing tape 23 is set in the polishing tape supply mechanism 2A in a state of being wound around the supply reel 24. The side surface of the polishing tape 23 is supported by a reel plate so that the winding collapse does not occur. One end of the polishing tape 23 is attached to the recovery reel 25, and the recovery reel 25 winds up the polishing tape 23 supplied to the polishing head assembly 1A to collect the polishing tape 23. The polishing head assembly 1A includes a polishing head 30 for bringing the polishing tape 23 supplied from the polishing tape supply mechanism 2A into contact with the peripheral edge of the wafer W. The polishing tape 23 is supplied to the polishing head 30 so that the polishing surface (front surface) of the polishing tape 23 faces the wafer W.

The polishing tape supply mechanism 2A has a plurality of guide rollers 31, 32, 33, 34, and the polishing tape 23 supplied to the polishing head assembly 1A and collected from the polishing head assembly 1A is the guide rollers 31. , 32, 33, 34. The polishing tape 23 is supplied from the supply reel 24 to the polishing head 30 through the opening 20a provided in the partition wall 20, and the used polishing tape 23 is collected by the recovery reel 25 through the opening 20a.

As shown in FIG. 2, an upper supply nozzle 36 is arranged above the wafer W, and the polishing liquid is supplied toward the center of the upper surface of the wafer W held by the substrate holding device 3. Further, the polishing apparatus includes a lower supply nozzle 37 that supplies the polishing liquid toward the boundary portion (the outer peripheral portion of the holding stage 4) between the back surface of the wafer W and the holding stage 4 of the substrate holding device 3. The upper supply nozzle 36 and the lower supply nozzle 37 function as a liquid supply unit that supplies the polishing liquid (liquid) to the wafer W held by the substrate holding device 3. Pure water is usually used as the polishing liquid, but ammonia can also be used when silica is used as the abrasive grains of the polishing tape 23. Further, the polishing apparatus includes a cleaning nozzle 38 for cleaning the polishing head 30 after the polishing process, and after the wafer W is raised by the substrate holding device 3 after the polishing process, cleaning water is sprayed toward the polishing head 30. The polishing head 30 after the polishing process can be cleaned.

As shown in FIG. 2, in order to isolate the mechanism such as the ball spline bearing 6 and the radial bearing 18 from the polishing chamber 21 when the hollow shaft 5 moves up and down with respect to the casing 12, the hollow shaft 5 and the upper end of the casing 12 are separated from each other. A bellows 19 that can be expanded and contracted up and down is arranged between them. FIG. 2 shows a state in which the hollow shaft 5 is lowered, and shows that the holding stage 4 is in the polishing position. After the polishing process, the wafer W is raised to the transfer position together with the holding stage 4 and the hollow shaft 5 by the air cylinder 15, and the wafer W is separated from the holding stage 4 at this transfer position.

The partition wall 20 includes a transport port 20b for loading and unloading the wafer W into and out of the polishing chamber 21. The transport port 20b is formed as a notch extending horizontally. Therefore, the wafer W gripped by the transfer mechanism can cross the inside of the polishing chamber 21 through the transfer port 20b while maintaining a horizontal state. An opening 20c and a louver 40 are provided on the upper surface of the partition wall 20, and an exhaust port (not shown) is provided on the lower surface. During the polishing process, the transport port 20b is closed by a shutter (not shown). Therefore, a downflow of clean air is formed inside the polishing chamber 21 by exhausting air from the exhaust port by a fan mechanism (not shown). Since the polishing treatment is performed in this state, the polishing liquid is prevented from being scattered upward, and the polishing treatment can be performed while keeping the upper space of the polishing chamber 21 clean.

As shown in FIG. 1, the polishing head 30 is fixed to one end of the arm 60, and the arm 60 is rotatably configured around a rotation axis Ct parallel to the tangential direction of the wafer W. The other end of the arm 60 is connected to the motor M4 via pulleys p3 and p4 and a belt b2. When the motor M4 rotates clockwise and counterclockwise by a predetermined angle, the arm 60 rotates about the axis Ct by a predetermined angle. In the present embodiment, the motor M4, the arm 60, the pulleys p3 and p4, and the belt b2 constitute a tilt mechanism that tilts the polishing head 30 with respect to the surface of the wafer W.

The tilt mechanism is mounted on the moving table 61. The moving table 61 is movably connected to the base plate 65 via the guide 62 and the rail 63. The rail 63 extends linearly along the radial direction of the wafer W held by the substrate holding device 3, and the moving table 61 can move linearly along the radial direction of the wafer W. A connecting plate 66 penetrating the base plate 65 is attached to the moving table 61, and a linear actuator 67 is connected to the connecting plate 66 via a joint 68. The linear actuator 67 is directly or indirectly fixed to the base plate 65.

As the linear actuator 67, a combination of an air cylinder, a positioning motor, and a ball screw can be adopted. The linear actuator 67, the rail 63, and the guide 62 constitute a moving mechanism for linearly moving the polishing head 30 in the radial direction of the wafer W. That is, the moving mechanism operates so as to move the polishing head 30 closer to and further from the wafer W along the rail 63. On the other hand, the polishing tape supply mechanism 2A is fixed to the base plate 65.

FIG. 4 is an enlarged view of the polishing head 30. As shown in FIG. 4, the polishing head 30 includes a pressing mechanism 41 that presses the polished surface of the polishing tape 23 against the wafer W with a predetermined force. Further, the polishing head 30 includes a tape feeding mechanism 42 for feeding the polishing tape 23 from the supply reel 24 to the collection reel 25. The polishing head 30 has a plurality of guide rollers 43, 44, 45, 46, 47, 48, 49, and these guide rollers allow the polishing tape 23 to advance in a direction orthogonal to the tangential direction of the wafer W. Guide the polishing tape 23.

The tape feeding mechanism 42 provided on the polishing head 30 includes a tape feeding roller 42a, a tape gripping roller 42b, and a motor M3 for rotating the tape feeding roller 42a. The motor M3 is provided on the side surface of the polishing head 30, and a tape feed roller 42a is attached to the rotating shaft of the motor M3. The tape gripping roller 42b is arranged adjacent to the tape feeding roller 42a. The tape gripping roller 42b is supported by a mechanism (not shown) so as to generate a force in the direction indicated by the arrow NF in FIG. 3 (direction toward the tape feed roller 42a), and is configured to press the tape feed roller 42a. ing.

When the motor M3 rotates in the direction of the arrow shown in FIG. 4, the tape feed roller 42a rotates and the polishing tape 23 can be fed from the supply reel 24 to the recovery reel 25 via the polishing head 30. The tape gripping roller 42b is configured to rotate about its own axis and rotates as the polishing tape 23 is fed.

The pressing mechanism 41 includes a pressing pad 50 arranged on the back surface side of the polishing tape 23, and an air cylinder (driving mechanism) 52 that moves the pressing pad 50 toward the peripheral edge of the wafer W. The air cylinder 52 is a so-called single rod cylinder. By controlling the air pressure supplied to the air cylinder 52, the force for pressing the polishing tape 23 against the wafer W is adjusted. The tilt mechanism, pressing mechanism 41, tape feeding mechanism 42, and moving mechanism for moving each polishing head assembly of the four polishing head assemblies 1A, 1B, 1C, and 1D arranged around the wafer W are independent of each other. It is configured to be operational.

In the present embodiment, the control unit 9 (FIG. 9) controls the operation of the entire polishing apparatus including the polishing head assembly 1A, 1B, 1C, 1D, the polishing tape supply mechanism 2A, 2B, 2C, 2D, the substrate holding device 3, and the like. 2) is provided. The control unit 9 controls the polishing process (board process) of the wafer W.

FIG. 5 is a diagram showing a state in which the polishing head 30 is polishing the bevel portion of the wafer W. When polishing the bevel portion of the wafer W, the wafer W is held by vacuum suction on the substrate holding surface 4a of the holding stage 4 and rotated. Further, the polishing liquid is supplied to the surface of the wafer W from the upper supply nozzle 36. The polishing liquid may be supplied to the peripheral edge of the wafer W from the lower supply nozzle 37. In this state, as shown in FIG. 5, the polishing tape 23 is pressed against the bevel portion of the wafer W by the pressing member 50 while continuously changing the tilt angle of the polishing head 30 by the tilt mechanism described above. During polishing, the polishing tape 23 is fed at a predetermined speed by the tape feeding mechanism 42.

During polishing of the bevel portion of the wafer W, a gas-liquid two-phase flow composed of a polishing liquid and an atmosphere is sucked into the vacuum line L1 that communicates the vacuum source and the substrate holding surface 4a. In order to prevent the vacuum source from being contaminated by the polishing liquid contained in the gas-liquid two-phase flow, the substrate holding device 3 of the polishing device includes a gas-liquid separation unit described below.

FIG. 6 is a schematic view of a substrate holding device 3 provided in the polishing device shown in FIGS. 1 and 2. As shown in FIG. 6, in this substrate holding device 3, the holding stage (board holding portion) 4 having the substrate holding surface 4a for holding the wafer W by vacuum suction and the vacuum for communicating the substrate holding surface 4a with the vacuum source. The line L1 and the gas-liquid separation unit 10 that separates the liquid from the gas-liquid two-phase flow sucked from the substrate holding surface 4a into the vacuum primary line L2 of the vacuum line L1 are provided. The operation of the entire substrate holding device 3 including the gas-liquid separation unit 10 is controlled by the control unit 9.

The gas-liquid separation unit 10 has a gas-liquid separation tank 16 that separates a polishing liquid (liquid) from a gas-liquid two-phase flow sucked into the vacuum primary line L2 of the vacuum line L1, and the gas-liquid two-phase flow is gas. In the liquid separation tank 16, gas (air) and liquid (polishing liquid) are separated from each other. The polishing liquid separated from the gas-liquid two-phase flow is stored in the gas-liquid separation tank 16, and the air separated from the gas-liquid two-phase flow is discharged through the vacuum secondary line L3 of the vacuum line L1.

Further, the gas-liquid separation unit 10 has a high liquid level sensor 71 capable of detecting the liquid level of the gas-liquid separation tank 16 and a low liquid level sensor 71 capable of detecting the liquid level of the gas-liquid separation tank 16 lower than the high liquid level sensor 71. A liquid level sensor 73, a discharge line L5 for discharging the polishing liquid (liquid) accumulated in the gas-liquid separation tank 16, and a drain valve 70 arranged in the discharge line L5 are provided. The high-liquid level sensor 71 and the low-liquid level sensor 73 are connected to the control unit 9 via a signal line (not shown), and the control unit 9 outputs from the high-liquid level sensor 71 and the low-liquid level sensor 73. It is possible to monitor the high liquid level and the low liquid level in the gas-liquid separation tank 16 by the signal generated. Further, the drain valve 70 is also connected to the control unit 9, and the opening / closing operation of the drain valve 70 is controlled by the control unit 9.

In the present embodiment, the gas-liquid separation unit 10 has a liquid level detection pipe 72 having both ends connected to the upper part and the lower part of the gas-liquid separation tank 16, and has a high liquid level sensor 71 and a low liquid level sensor 73. Is arranged in the liquid level detection pipe 72. The liquid level detection pipe 72 communicates with the gas-liquid separation tank 16 at both ends thereof, and the liquid collected in the gas-liquid separation tank 16 flows into the liquid level detection pipe 72 from the lower end of the liquid level detection pipe 72. To do. Therefore, the liquid level in the liquid level detection pipe 72 is the same as the liquid level S in the gas-liquid separation tank 16. As the high liquid level sensor 71 and the low liquid level sensor 73, any sensor capable of detecting the liquid level S in the gas-liquid separation tank 16 (in the present embodiment, the liquid level in the liquid level detection pipe 72) can be used. it can. Such a sensor is, for example, an optical sensor including a light emitting unit and a light receiving unit, or a capacitance type sensor including a detection electrode and a ground electrode.

In the present embodiment, the high liquid level sensor 71 and the low liquid level sensor 73 do not generate a signal output to the control unit 9 when the liquid level is not detected, but detect the liquid level. Is configured to output a signal to the control unit 9. In this case, when the high liquid level sensor 71 or the low liquid level sensor 73 detects the liquid level, the control unit 9 receives an ON signal from the high liquid level sensor 71 or the low liquid level sensor 73. Alternatively, the high liquid level sensor 71 and the low liquid level sensor 73 output a signal to the control unit 9 when the liquid level is not detected, while the low liquid level sensor 73 outputs a signal to the control unit 9 when the liquid level is detected. It may be configured to stop the generation of the output signal. In this case, when the high liquid level sensor 71 or the low liquid level sensor 73 detects the liquid level, the control unit 9 receives an OFF signal from the high liquid level sensor 71 or the low liquid level sensor 73.

The high liquid level sensor 71 is arranged above the low liquid level sensor 73, and functions as a full liquid sensor that prevents the liquid accumulated in the gas-liquid separation tank 16 from overflowing from the gas-liquid separation tank 16. More specifically, the control unit 9 monitors the upper limit of the liquid level in the gas-liquid separation tank 16 by the signal output from the high liquid level sensor 71. When the control unit 9 receives the signal output from the high liquid level sensor 71, the control unit 9 has a polishing device (board processing) including a substrate holding device 3 in order to prevent the liquid from overflowing from the gas-liquid separation tank. Device) Stop the entire operation.

The low liquid level sensor 73 is arranged below the high liquid level sensor 71, and detects a liquid level lower than the liquid level detected by the high liquid level sensor 71. The control unit 9 controls the opening / closing operation of the drain valve 70 based on the signal output from the low liquid level sensor 73, and executes a drainage process for discharging the liquid accumulated in the gas-liquid separation tank 16. When the control unit 9 opens the drain valve 70, the polishing liquid accumulated in the gas-liquid separation tank 16 is discharged from the gas-liquid separation tank 16 via the discharge line L5.

As shown in FIG. 6, the gas-liquid separation unit 10 preferably includes an extrusion line L6 connected to the gas-liquid separation tank 16 and an extrusion gas supply valve 79 arranged in the extrusion line L6. The extruded gas supply valve 79 is connected to the control unit 9, and the control unit 9 controls the opening / closing operation of the extruded gas supply valve 79. The extrusion line L6 extends from a gas supply source (not shown) to the upper part of the gas-liquid separation tank 16, and when the extrusion gas supply valve 79 is opened, a pressurized gas (for example, pressurized air or pressurized nitrogen) is released. It is supplied to the gas-liquid separation tank 16. When the extruded gas supply valve 79 is opened while the drain valve 70 is open, the pressurized gas is supplied to the gas-liquid separation tank 16 and the polishing liquid accumulated in the gas-liquid separation tank 16 is pushed out to the discharge line L5. As a result, the drainage treatment for discharging the liquid accumulated in the gas-liquid separation tank 16 is promoted.

As shown in FIG. 6, the gas-liquid separation unit 10 of the substrate holding device 3 may include a purge line L7 that branches from the extrusion line L6 and is connected to the liquid level detection pipe 72. The purge line L7 is branched from the extrusion line L6 at a branch point P1 provided between the extrusion gas supply valve 79 and the gas-liquid separation tank 16, and is connected to the upper part of the liquid level detection pipe 72. More specifically, the purge line L7 is connected to the liquid level detection pipe 72 above the high liquid level sensor 71.

When the control unit 9 opens the extrusion gas supply valve 79 to promote the drainage treatment, the pressurized gas is supplied to the gas-liquid separation tank 16 via the extrusion line L6, and at the same time, the liquid is supplied to the gas-liquid separation tank 16 via the purge line L7. Pressurized gas is supplied to the surface detection pipe 72. When the liquid level S in the gas-liquid separation tank 16 is lowered by the liquid drainage treatment, the liquid level of the liquid level detection pipe 72 is also lowered. At this time, the high liquid level sensor 71 or the low liquid level sensor 73 may erroneously detect the liquid level S of the gas-liquid separation tank 16 due to the droplets remaining on the liquid level detection pipe 72. In the present embodiment, the pressurized gas is supplied from the purge line L7 to the liquid level detection pipe 72 during the drainage treatment. Since this pressurized gas moves the droplets remaining in the liquid level detection pipe 72 downward (that is, toward the liquid level in the liquid level detection pipe 72), the high liquid level sensor 71 or the low liquid level False detection of the sensor 73 can be effectively prevented.

As shown in FIG. 6, it is preferable that the purge line L7 is provided with a flow rate regulator 80 for adjusting the flow rate of the gas flowing through the purge line L7. The flow rate regulator 80 is, for example, a flow rate adjusting valve. By adjusting the flow rate of the gas supplied to the liquid level detection pipe 72 with the flow rate regulator 80, it is possible to prevent the liquid level in the gas liquid level detection pipe 72 from swelling. As a result, the high liquid level sensor 71 and the low liquid level sensor 73 are prevented from erroneously detecting the liquid level.

Next, with reference to FIGS. 7 to 12, the polishing process performed by the polishing apparatus including the substrate holding apparatus 3 described above will be described. FIG. 7 is a flowchart of a polishing process executed by the polishing apparatus shown in FIGS. 1 and 2. 8 to 12 are schematic views showing each step of polishing the wafer W held by the substrate holding device 3 shown in FIG. More specifically, FIG. 8 is a diagram showing a state in which the wafer W is conveyed above the substrate holding device 3, and FIG. 9 is a diagram in which the wafer W is the substrate holding surface 4a of the holding stage 4 of the substrate holding device 3. FIG. 10 is a diagram showing a state of being held by vacuum suction, and FIG. 10 is a diagram showing a state of polishing the bevel portion of the wafer W held on the substrate holding surface 4a of the holding stage 4. FIG. 11 is a diagram showing a state in which the wafer W is separated from the substrate holding surface 4a of the holding stage 4 after the polishing process of the wafer W is completed, and FIG. 12 is a diagram after the polishing process of the wafer W is completed. , It is a figure which shows the state which the drainage process is executed. In FIGS. 8 to 12, the valve filled in black represents the valve opened by the control unit 9, and the white valve represents the closed valve.

As shown in FIG. 8, when the polishing device performs the polishing process of the wafer W, the wafer W is first subjected to the substrate holding device 3 by a transfer mechanism (not shown) controlled by the control unit 9. It is conveyed above the holding stage 4. Next, the control unit 9 controls the transfer mechanism to place the wafer W on the substrate holding surface 4a of the holding stage 4 (step 1 in FIG. 7). Next, as shown in FIG. 9, the control unit 9 connects to the communication valve 75 arranged in the vacuum primary line L2 which is a part of the vacuum line L1 and the vacuum secondary line L3 which is a part of the vacuum line L1. The arranged vacuum source valve 77 is opened to communicate the vacuum source with the substrate holding surface 4a. As a result, the wafer W is held on the substrate holding surface 4a by vacuum suction (step 2 in FIG. 7).

Next, the control unit 9 executes a polishing process (substrate processing) of the wafer W (step 3 in FIG. 7). More specifically, as shown in FIG. 10, the control unit 9 rotates the substrate stage 4 and polishes the upper surface of the wafer W vacuum-adsorbed from the upper supply nozzle 36 to the substrate holding surface 4a of the substrate stage 4. Supply the liquid. At this time, the polishing liquid may be supplied to the peripheral edge of the wafer W from the lower supply nozzle 37 (see FIG. 2). Further, the control unit 9 moves the polishing head 30 toward the bevel portion of the wafer W and presses the polishing tape 23 against the bevel portion of the wafer W. As a result, the bevel portion of the wafer W is polished. During polishing of the bevel portion of the wafer W, the polishing head 30 can continuously change the inclination angle with respect to the wafer W by the above-mentioned tilt mechanism (see FIG. 5).

Further, during polishing of the bevel portion of the wafer W, the gas-liquid two-phase flow composed of the polishing liquid supplied from the upper supply nozzle 36 (and / or the lower supply nozzle 37) and the atmosphere flows into the vacuum primary line L2 of the vacuum line L1. It flows into the gas-liquid separation tank 16 through the gas-liquid separation tank 16. This gas-liquid two-phase flow is separated into a gas (that is, air) and a liquid (that is, a polishing liquid) in the gas-liquid separation tank 16 (step 4 in FIG. 7), and the air is a vacuum secondary of the vacuum line L1. It is discharged from the polishing apparatus through the line L3. On the other hand, since the polishing liquid is stored in the gas-liquid separation tank 16, the liquid level S in the gas-liquid separation tank 16 rises.

As shown in FIG. 11, when the polishing process of the wafer W is completed, the control unit 9 moves the polishing head 30 away from the wafer W and polishes from the upper supply nozzle 36 (and / or the lower supply nozzle 37). Stop the supply of liquid. Further, the control unit 9 stops the rotation of the wafer W. Next, the control unit 9 closes the vacuum source valve 77 and opens the gas supply valve 78 of the gas supply line L4. As a result, the pressurized gas is supplied to the substrate holding surface 4a of the holding stage 4 via the vacuum primary line L2. In this state, the control unit 9 controls the transfer mechanism to separate the wafer W from the substrate holding surface 4a of the holding stage 4 (step 5 in FIG. 7). When the wafer W is separated from the substrate holding surface 4a by the transfer mechanism, the control unit 9 closes the communication valve 75 and the gas supply valve 78.

At this time, the control unit 9 confirms whether or not the low liquid level sensor 73 has detected the liquid level. More specifically, the control unit 9 confirms whether or not a signal is output from the low liquid level sensor 73 (step 6 in FIG. 7). As shown in FIG. 11, when the liquid level S of the gas-liquid separation tank 16 is located below the liquid level detection position of the low liquid level sensor 73, the low liquid level sensor 73 is sent to the control unit 9. No signal is output. In this case, the control unit 9 returns to step 1 in order to execute the polishing process of the next wafer W, conveys the next wafer W above the holding stage 4 of the substrate holding device 3, and causes the holding stage. It is placed on the substrate holding surface 4a of No. 4 (see FIGS. 8 and 9). The distance between the high liquid level sensor 71 and the low liquid level sensor 73 is such that the liquid level S of the gas-liquid separation tank 16 is the liquid level detection position of the high liquid level sensor 71 even if the next wafer W polishing process is executed. It is set to a distance that does not reach.

On the other hand, as shown in FIG. 12, when the liquid level S of the gas-liquid separation tank 16 is higher than the liquid level detection position of the low liquid level sensor 73, a signal is output from the low liquid level sensor 73 to the control unit 9. Will be done. The control unit 9 that has received the output signal from the low liquid level sensor 73 executes a drainage process for discharging the polishing liquid accumulated in the gas-liquid separation tank 16 (step 7 in FIG. 7). More specifically, the control unit 9 opens the drain valve 70 arranged in the discharge line L5, further opens the extrusion gas supply valve 79 arranged in the extrusion line L6, and separates the pressurized gas into a gas-liquid separation tank. It is supplied to 16 and the liquid level detection pipe 72. As a result, the polishing liquid accumulated in the gas-liquid separation tank 16 is efficiently discharged from the gas-liquid separation tank 16 via the discharge line L5, and the droplets adhering to the inner surface of the liquid level detection pipe 72 are removed. To.

The control unit 9 drains until the liquid level S of the gas-liquid separation tank 16 is located below the liquid level detection position of the low liquid level sensor 73 (that is, until the output from the low liquid level sensor 73 stops). Perform liquid treatment. During the drainage process, the control unit 9 monitors whether or not the drainage process is reliably executed. More specifically, the control unit 9 stores the upper limit value T1 with respect to the execution time of the drainage process in advance, and compares the upper limit value T1 with the elapsed time T2 counted after opening the drain valve 70. (Step 8 in FIG. 7). If the output from the low liquid level sensor 73 is stopped before the elapsed time T2 reaches the upper limit value T1, the control unit 9 determines that the drainage process has been performed reliably. In this case, the control unit 9 closes the drain valve 70 arranged in the discharge line L5 and the extruded gas supply valve 79 arranged in the extrusion line L6 to end the liquid drainage process (step 9 in FIG. 7). When the drainage process is completed, the control unit 9 returns to step 1, transports the next wafer W above the holding stage 4 of the substrate holding device 3, and places it on the substrate holding surface 4a of the holding stage 4. (See FIGS. 8 and 9).

On the other hand, if the output from the low liquid level sensor 73 does not stop even if the elapsed time T2 exceeds the upper limit value T1, the control unit 9 determines that the drainage process has not been reliably performed. In this case, the control unit 9 outputs an alarm (step 10 in FIG. 7) and stops the next wafer W transfer operation. As a result, the operator of the polishing apparatus can detect a defect such as clogging of the discharge line L5 when the polishing process of the wafer W is not executed, so that the disposal of the wafer W can be effectively prevented. be able to.

As described above, according to the present embodiment, the gas-liquid separation unit 10 has two liquid level sensors (that is, a high liquid level sensor 71 and a low liquid level sensor 73) capable of detecting the liquid level of the gas-liquid separation tank 16. have. The control unit 9 executes the drainage process of discharging the liquid from the gas-liquid separation tank 16 only when the low liquid level sensor 73 detects the liquid level. That is, if the low liquid level sensor 73 does not detect the liquid level, the control unit 9 starts the polishing process of the next wafer W without executing the drainage process. As a result, the throughput of substrate processing can be improved. Further, since the control unit 9 can monitor whether or not the drainage treatment is reliably performed based on the output signal of the low liquid level sensor 73, the wafer W can be effectively prevented from being disposed of. be able to.

FIG. 13 is a schematic view showing the substrate holding device 3 according to another embodiment. Since the configuration and operation of the present embodiment not particularly described are the same as those of the substrate holding device 3 shown in FIG. 6, the duplicated description thereof will be omitted.

The substrate holding device 3 shown in FIG. 13 differs from the substrate holding device 3 shown in FIG. 6 in that it has a plurality of (two in FIG. 13) gas-liquid separation units 10a and 10b. The first gas-liquid separation unit 10a and the second gas-liquid separation unit 10b have the same configuration as the gas-liquid separation unit 10 shown in FIG. 6, except for the intermediate liquid level sensor described later. The components of the present embodiment corresponding to the components of the gas-liquid separation unit 10 shown in FIG. 6 are designated by the same reference numerals different only in the subscripts (that is, “a” and “b”) in detail. The description is omitted.

The vacuum primary line L2 of the vacuum line L1 branches to the first branch line L2-1 and the second branch line L2-2 at the branch point P2. The first branch line L2-1 extends from the branch point P2 to the first gas-liquid separation tank 16a of the first gas-liquid separation unit 10a, and the second branch line L2-2 extends from the branch point P2 to the second gas-liquid separation unit. It extends to the second gas-liquid separation tank 16b of 10b. A part of the vacuum primary line L2 extending from the branch point P2 to the substrate holding surface 4a functions as a common line L2-3.

The first communication valve 75a of the first gas-liquid separation unit 10a is arranged at the first branch line L2-1, and the second communication valve 75b of the second gas-liquid separation unit 10b is the second branch line L2-2. It is located in. When the first communication valve 75a and the first vacuum source valve 77a are opened, the substrate holding surface 4a of the holding holder 4 communicates with the vacuum source via the first gas-liquid separation tank 16a of the first separation unit 10a. Similarly, when the second communication valve 75b and the second vacuum source valve 77b are opened, the substrate holding surface 4a of the holding holder 4 communicates with the vacuum source via the second gas-liquid separation tank 16b of the second separation unit 10b.

The first gas-liquid separation unit 10a has a first high liquid level sensor 71a and a first low liquid level sensor 73a arranged in the first liquid level detection pipe 72a, and further, these liquid level sensors 71a, 73a. It is provided with a first intermediate liquid level sensor 76a arranged between the two. The first intermediate liquid level sensor 76a is arranged above the first low liquid level sensor 73a and below the first high liquid level sensor 71a. The first intermediate liquid level sensor 76a can detect the liquid level between the liquid level detected by the first high liquid level sensor 71a and the liquid level detected by the first low liquid level sensor 73a. As the first intermediate liquid level sensor 76a, any sensor (for example, an optical sensor or an optical sensor) capable of detecting the liquid level of the first gas-liquid separation tank 16a (in the present embodiment, the liquid level of the first liquid level detection pipe 72a) can be detected. Capacitive sensor) can be used.

Similarly, the second gas-liquid separation unit 10b has a second high liquid level sensor 71b and a second low liquid level sensor 73b arranged in the second liquid level detection pipe 72b, and further, these liquid level sensors. A second intermediate liquid level sensor 76b arranged between 71b and 73b is provided. The second intermediate liquid level sensor 76b is arranged above the second low liquid level sensor 73b and below the second high liquid level sensor 71b. The second intermediate liquid level sensor 76b can detect the liquid level between the liquid level detected by the second high liquid level sensor 71b and the liquid level detected by the second low liquid level sensor 73b. As the second intermediate liquid level sensor 76b, any sensor (for example, an optical sensor or an optical sensor) capable of detecting the liquid level of the second gas-liquid separation tank 16b (in the present embodiment, the liquid level of the second liquid level detection pipe 72b) can be detected. Capacitive sensor) can be used.

In the present embodiment, the control unit 9 drains liquid based on the output signals of the first low liquid level sensor 73a, the first intermediate liquid level sensor 76a, the second low liquid level sensor 73b, and the second intermediate liquid level sensor 76b. Control the processing operation. More specifically, the control unit 9 controls the opening / closing operation of the first drain valve 70a based on the output signals of the first low liquid level sensor 73a and the first intermediate liquid level sensor 76a, and the second low liquid level sensor. The opening / closing operation of the second drain valve 70b is controlled based on the output signals of the 73b and the second intermediate liquid level sensor 76b.

Next, with reference to FIGS. 14 to 20, the polishing process performed by the polishing apparatus including the substrate holding apparatus 3 shown in FIG. 13 will be described. FIG. 14 is a flowchart of the polishing process of the wafer W held by the substrate holding device 3 shown in FIG. 15 to 20 are schematic views showing each step of polishing the wafer W held by the substrate holding device 3 shown in FIG. 13. More specifically, FIG. 15 is a diagram showing a state in which the wafer W is conveyed above the substrate holding device 3, and FIG. 16 shows a substrate holding surface 4a of the holding stage 4 of the substrate holding device 3 in which the wafer W is conveyed. FIG. 17 is a diagram showing a state of being held by vacuum suction, and FIG. 17 is a diagram showing a state of polishing the bevel portion of the wafer W held on the substrate holding surface 4a of the holding stage 4. FIG. 18 is a diagram showing a state in which the first intermediate liquid level sensor 76a detects the liquid level S in the first gas-liquid separation tank 16a during polishing of the wafer W. FIG. 19 is a diagram showing a state in which the wafer W is separated from the substrate holding surface 4a of the holding stage 4 after the polishing process of the wafer W is completed, and FIG. 20 is a diagram showing a state after the polishing process of the wafer W is completed. , It is a figure which shows the state which the drainage process is executed. In FIGS. 15 to 20, the valve filled in black represents the valve opened by the control unit 9, and the white valve represents the closed valve.

As shown in FIG. 15, when the polishing device performs the polishing process of the wafer W, the wafer W is first subjected to the substrate holding device 3 by a transfer mechanism (not shown) controlled by the control unit 9. It is conveyed above the holding stage 4. Next, the control unit 9 controls the transfer mechanism to place the wafer W on the substrate holding surface 4a of the holding stage 4 (step 1 in FIG. 14). Next, as shown in FIG. 16, the control unit 9 has a first communication valve 75a arranged on the first branch line L2-1 and a first vacuum source valve 77a arranged on the first vacuum secondary line L3a. Is opened, and the vacuum source is communicated with the substrate holding surface 4a via the first gas-liquid separation tank 16a. As a result, the wafer W is held on the substrate holding surface 4a by vacuum suction (step 2 in FIG. 14).

Next, the control unit 9 executes a polishing process (substrate processing) of the wafer W (step 3 in FIG. 14). More specifically, as shown in FIG. 17, the control unit 9 rotates the substrate stage 4 and polishes the upper surface of the wafer W vacuum-adsorbed from the upper supply nozzle 36 to the substrate holding surface 4a of the substrate stage 4. Supply the liquid. At this time, the polishing liquid may be supplied to the peripheral edge of the wafer W from the lower supply nozzle 37 (see FIG. 2). Further, the control unit 9 moves the polishing head 30 toward the bevel portion of the wafer W and presses the polishing tape 23 against the bevel portion of the wafer W. As a result, the bevel portion of the wafer W is polished. During polishing of the bevel portion of the wafer W, the polishing head 30 can continuously change the inclination angle with respect to the wafer W by the above-mentioned tilt mechanism (see FIG. 5).

Further, during polishing of the bevel portion of the wafer W, the gas-liquid two-phase flow composed of the polishing liquid supplied from the upper supply nozzle 36 (and / or the lower supply nozzle 37) and the atmosphere flows into the vacuum primary line L2 of the vacuum line L1. (In this embodiment, it flows into the first gas-liquid separation tank 16a through the common line L2-3 and the first branch line L2-1). This gas-liquid two-phase flow is separated into a gas (that is, air) and a liquid (that is, a polishing liquid) in the first gas-liquid separation tank 16a (step 4 in FIG. 14), and the air is secondary to the first vacuum. It is discharged from the polishing apparatus through the line L3a. On the other hand, since the polishing liquid is stored in the first gas-liquid separation tank 16a, the liquid level Sa in the first gas-liquid separation tank 16a rises.

While polishing the wafer W, the control unit 9 monitors whether or not a signal is output from the first intermediate liquid level sensor 76a (step 5 in FIG. 14). As shown in FIG. 18, when the liquid level Sa of the first gas-liquid separation tank 16a is located above the liquid level detection position of the first intermediate liquid level sensor 76a, the first intermediate liquid level sensor 76a Outputs a signal to the control unit 9. Upon receiving the output signal from the first intermediate liquid level sensor 76a, the control unit 9 sets the gas-liquid separation tank into which the gas-liquid two-phase flow sucked from the substrate holding surface 4a is introduced into the first gas-liquid separation unit 10a. The 1-gas-liquid separation tank 16a is switched to the second gas-liquid separation tank 16b of the second gas-liquid separation unit 10b (step 6 in FIG. 14). More specifically, the control unit 9 opens the second communication valve 75b and the second vacuum source valve 77b of the second gas-liquid separation unit 10b, and opens the first communication valve 75a and the first communication valve 75a of the first gas-liquid separation unit 10a. Close the vacuum main valve 77a. As a result, the gas-liquid two-phase flow sucked from the substrate holding surface 4a is introduced into the second gas-liquid separation tank 16b, and becomes a gas (that is, air) and a liquid (that is, a polishing liquid) in the gas-liquid separation tank 16b. Separated from each other. The polishing liquid separated from the gas-liquid two-phase flow in the second gas-liquid separation tank 16b accumulates in the second gas-liquid separation tank 16b, and the liquid level Sb in the second gas-liquid separation tank 16b rises.

Next, the control unit 9 executes a drainage process for discharging the polishing liquid accumulated in the first gas-liquid separation tank 16a (step 7 in FIG. 14). More specifically, the control unit 9 opens the first drain valve 70a arranged in the first discharge line L5a, and further opens the first extruded gas supply valve 79a arranged in the first extrusion line L6a. Pressurized gas is supplied to the first gas-liquid separation tank 16a and the first liquid level detection pipe 72a. As a result, the polishing liquid accumulated in the first gas-liquid separation tank 16a is efficiently discharged from the first gas-liquid separation tank 16a via the first discharge line L5a, and the inner surface of the first liquid level detection pipe 72a. The droplets adhering to the water are removed.

In the control unit 9, until the liquid level Sa of the first gas-liquid separation tank 16a is located below the liquid level detection position of the first low liquid level sensor 73a (that is, the output from the first low liquid level sensor 73a is output. Perform drainage treatment (until it stops). During the drainage process, the control unit 9 monitors whether or not the drainage process is reliably executed. More specifically, the control unit 9 stores the upper limit value T1'with respect to the execution time of the drainage process in advance, and the elapsed time T2 counted after opening the upper limit value T1'and the first drain valve 70a. Compared with'(step 8 in FIG. 14). If the output from the first low liquid level sensor 73a is stopped before the elapsed time T2'reaches the upper limit value T1', the control unit 9 determines that the drainage process has been performed reliably. In this case, the control unit 9 closes the first drain valve 70a arranged in the first discharge line L5a and the first extruded gas supply valve 79a arranged in the first extrusion line L6a to end the liquid drainage process. (Step 9 in FIG. 7), the first gas-liquid separation tank 16a is made to stand by.

On the other hand, if the output from the first low liquid level sensor 73a does not stop even if the elapsed time T2'exceeds the upper limit time T1', the control unit 9 determines that the drainage process has not been performed reliably. To do. In this case, the control unit 9 outputs an alarm (step 10 in FIG. 7) and puts the first gas-liquid separation tank 16a on standby.

In the present embodiment, gas-liquid separation in which a gas-liquid two-phase flow is introduced when the liquid level Sa in the first gas-liquid separation tank 16a becomes higher than the liquid level detection position of the first intermediate liquid level sensor 76a. The tank is switched from the first gas-liquid separation tank 16a to the second gas-liquid separation tank 16b. Further, while the liquid is separated from the gas-liquid two-phase flow in the second gas-liquid separation tank 16b, a drainage treatment for discharging the polishing liquid from the first gas-liquid separation tank 16a is executed. If the liquid level Sb in the second gas-liquid separation tank 16b becomes higher than the liquid level detection position of the second intermediate liquid level sensor 76b during polishing of the wafer W, the control unit 9 controls the gas-liquid two-phase. The gas-liquid separation tank into which the flow is introduced may be switched from the second gas-liquid separation tank 16b to the first gas-liquid separation tank 16a. In this case, the control unit 9 executes a drainage process for discharging the polishing liquid from the second gas-liquid separation tank 16b.

As described above, according to the substrate holding device 3 of the present embodiment, the gas-liquid separation tank into which the gas-liquid two-phase flow is introduced during the polishing of the wafer W separates the second gas-liquid from the first gas-liquid separation tank 16a. It is switched to the tank 16b (or from the second gas-liquid separation tank 16b to the first gas-liquid separation tank 16a). Therefore, even when the polishing time of the wafer W is long, the liquid level Sa (or liquid level Sb) in the first gas-liquid separation tank 16a (or the second gas-liquid separation tank 16b) is the first high liquid level sensor 71a (or the liquid level Sb). Alternatively, since the liquid level detection position of the second high liquid level sensor 71b) is not reached, the polishing process does not stop. As a result, since there is no restriction on the polishing time of the wafer W, the wafer W can be polished by any polishing recipe.

In step 5 of FIG. 14, when the polishing of the wafer W is completed without outputting a signal from the first intermediate liquid level sensor 76a to the control unit 9, the control unit 9 performs the polishing head 30 as shown in FIG. Is moved away from the wafer W to stop the supply of the polishing liquid from the upper supply nozzle 36 (and / or the lower supply nozzle 37). Further, the control unit 9 stops the rotation of the wafer W. Next, the control unit 9 closes the first vacuum source valve 77a and opens the first gas supply valve 78a of the first gas supply line L4a. As a result, the pressurized gas is supplied to the substrate holding surface 4a of the holding stage 4 via the first branch line L2-1 and the common line L2-3. In this state, the control unit 9 controls the transfer mechanism to separate the wafer W from the substrate holding surface 4a of the holding stage 4 (step 11 in FIG. 14). When the wafer W is separated from the substrate holding surface 4a by the transfer mechanism, the control unit 9 closes the first communication valve 75a and the first gas supply valve 78a.

At this time, the control unit 9 confirms whether or not the first low liquid level sensor 73a has detected the liquid level. More specifically, the control unit 9 confirms whether or not a signal is output from the first low liquid level sensor 73a (step 12 in FIG. 7). As shown in FIG. 19, when the liquid level Sa of the first gas-liquid separation tank 16a is located below the liquid level detection position of the first low liquid level sensor 73a, the first low liquid level sensor 73a Does not output a signal to the control unit 9. In this case, the control unit 9 returns to step 1 in order to execute the polishing process of the next wafer W, conveys the next wafer W above the holding stage 4 of the substrate holding device 3, and causes the holding stage. It is placed on the substrate holding surface 4a of No. 4 (see FIGS. 15 and 16).

On the other hand, as shown in FIG. 20, when the liquid level Sa of the first gas-liquid separation tank 16a is higher than the liquid level detection position of the first low liquid level sensor 73a, it is controlled from the first low liquid level sensor 73a. A signal is output to unit 9. The control unit 9 that has received the output signal from the first low-liquid level sensor 73a executes a drainage process for discharging the polishing liquid accumulated in the first gas-liquid separation tank 16a (step 13 in FIG. 14). More specifically, the control unit 9 opens the first drain valve 70a arranged in the first discharge line L5a, and further opens the first extruded gas supply valve 79a arranged in the first extrusion line L6a. Pressurized gas is supplied to the first gas-liquid separation tank 16a and the first liquid level detection pipe 72a. As a result, the polishing liquid accumulated in the first gas-liquid separation tank 16a is efficiently discharged from the first gas-liquid separation tank 16a via the first discharge line L5a, and the inner surface of the first liquid level detection pipe 72a. The droplets adhering to the water are removed.

In the control unit 9, until the liquid level Sa of the first gas-liquid separation tank 16a is located below the liquid level detection position of the first low liquid level sensor 73a (that is, the output from the first low liquid level sensor 73a is output. Perform drainage treatment (until it stops). During the drainage process, the control unit 9 monitors whether or not the drainage process is reliably executed. More specifically, the control unit 9 stores the upper limit value T1 with respect to the execution time of the drainage process in advance, and stores the upper limit value T1 and the elapsed time T2 counted after opening the first drain valve 70a. Comparison is made (step 14 in FIG. 7). If the output from the first low liquid level sensor 73a is stopped before the elapsed time T2 reaches the upper limit value T1, the control unit 9 determines that the drainage process has been reliably performed. In this case, the control unit 9 closes the first drain valve 70a arranged in the first discharge line L5a and the first extrusion gas supply valve 79a arranged in the first extrusion line L6a to end the liquid drainage process. (Step 15 in FIG. 7). When the drainage process is completed, the control unit 9 returns to step 1, transports the next wafer W above the holding stage 4 of the substrate holding device 3, and places it on the substrate holding surface 4a of the holding stage 4. (See FIGS. 15 and 16).

On the other hand, if the output from the first low liquid level sensor 73a does not stop even if the elapsed time T2 exceeds the upper limit time T, the control unit 9 determines that the drainage process has not been reliably performed. In this case, the control unit 9 outputs an alarm (step 11 in FIG. 7) and stops the next wafer W transfer operation. As a result, the operator of the polishing apparatus can detect a defect such as clogging of the first discharge line L5a when the polishing process of the wafer W is not executed, so that the wafer W can be effectively disposed of. Can be prevented.

As described above, also in the present embodiment, the control unit 9 performs the first gas-liquid separation tank 16a (or the first gas-liquid separation tank 16a) only when the first low-liquidity sensor 73a (or the second low-liquidity sensor 73b) detects the liquid level. Alternatively, a drainage treatment for discharging the liquid from the second gas-liquid separation tank 16b) is performed. That is, if the first low liquid level sensor 73a (or the second low liquid level sensor 73b) does not detect the liquid level, the control unit 9 does not execute the drainage process and polishes the next wafer W. To start. As a result, the throughput of substrate processing can be improved. Further, the control unit 9 can monitor whether or not the drainage process is reliably performed based on the output signal of the first low liquid level sensor 73a (or the second low liquid level sensor 73b). Therefore, the disposal of the wafer W can be effectively prevented.

As described above, the operation of the polishing device (board processing device) including the board holding device 3 is controlled by the control unit 9. In the present embodiment, the control unit 9 is composed of a dedicated computer or a general-purpose computer. FIG. 21 is a schematic view showing an example of the configuration of the control unit 9. The control unit 9 includes a storage device 110 that stores programs and data, a processing device 120 such as a CPU (central processing unit) that performs calculations according to the program stored in the storage device 110, data, programs, and various types. It includes an input device 130 for inputting information to the storage device 110, an output device 140 for outputting processing results and processed data, and a communication device 150 for connecting to a network such as the Internet.

The storage device 110 includes a main storage device 111 accessible to the processing device 120 and an auxiliary storage device 112 for storing data and programs. The main storage device 111 is, for example, a random access memory (RAM), and the auxiliary storage device 112 is a storage device such as a hard disk drive (HDD) or a solid state drive (SSD).

The input device 130 includes a keyboard and a mouse, and further includes a recording medium reading device 132 for reading data from the recording medium and a recording medium port 134 to which the recording medium is connected. The recording medium is a computer-readable recording medium that is a non-temporary tangible object, and is, for example, an optical disk (for example, CD-ROM or DVD-ROM) or a semiconductor memory (for example, a USB flash drive or a memory card). is there. Examples of the recording medium reading device 132 include an optical drive such as a CD drive and a DVD drive, and a card reader. An example of the recording medium port 134 is a USB terminal. The program and / or data stored in the recording medium is introduced into the control unit 9 via the input device 130 and stored in the auxiliary storage device 112 of the storage device 110. The output device 140 includes a display device 141 and a printing device 142.

The control unit 9 operates according to a program electrically stored in the storage device 110. That is, the control unit 9 holds the wafer W on the substrate holding surface 4a by vacuum suction (see step 2 in FIG. 7 and step 2 in FIG. 14), and supplies the polishing liquid to the wafer W while supplying the wafer W. From the substrate holding surface 4a in the step (see step 3 in FIG. 7 and step 3 in FIG. 14) and the gas-liquid separation tank 16 (or the first gas-liquid separation tank 16a) for executing the polishing process (substrate processing). After the step of separating the polishing liquid (liquid) from the sucked gas-liquid two-phase flow (see step 4 of FIG. 7 and step 4 of FIG. 14) and the polishing process of the wafer W are completed, the low liquid level sensor Based on the signal output from the 73 (or the first low liquid level sensor 73a), the step of executing the drainage process (see step 7 of FIG. 7 or step 13 of FIG. 14) is executed. The control unit 9 of the polishing device including the substrate holding device 3 shown in FIG. 13 is based on the output signal of the first intermediate liquid level sensor 76a of the first gas-liquid separation unit 16a during the polishing process of the wafer W. A step of switching the gas-liquid separation tank into which the liquid two-phase flow is introduced from the first gas-liquid separation tank 16a to the second gas-liquid separation tank 16b (see step 6 in FIG. 14) and the drainage of the first gas-liquid separation tank 16a. The step of executing the liquid treatment (see step 7 of FIG. 14) and the step of executing the liquid treatment are further executed.

The program for causing the control unit 9 to execute these steps is recorded on a computer-readable recording medium that is a non-temporary tangible object, and is provided to the control unit 9 via the recording medium. Alternatively, the program may be provided to the control unit 9 via a communication network such as the Internet.

In the above-described embodiment, a polishing device (board processing device) for polishing the bevel portion of the wafer W has been described, but the present invention is not limited to this example. For example, the substrate holding device 3 described above may be a substrate holding device arranged in a polishing device that polishes the surface of the wafer W.

FIG. 22 is a schematic view showing a substrate processing apparatus according to another embodiment. The substrate processing apparatus shown in FIG. 22 is a polishing apparatus for polishing the surface of a wafer W, which is an example of a substrate. The polishing apparatus shown in FIG. 22 has a top ring (substrate holding portion) 4 that holds and rotates a wafer W, which is an example of a substrate, a polishing table 153 that supports the polishing pad 152, and a polishing liquid (liquid) on the polishing pad 152. ) Is provided with a polishing liquid supply unit 155. The polishing table 153 is connected to a table motor 159 arranged below the table shaft 153a via a table shaft 153a, and can rotate around the table shaft 153a. In the present embodiment, the substrate holding device 3 has a top ring 4, a vacuum line L1 for communicating the lower surface of the top ring 4 with a vacuum source, and a gas-liquid separation unit 10. The configuration and operation of the gas-liquid separation unit 10 shown in FIG. 22 is the same as the configuration and operation of the gas-liquid separation unit 10 described with reference to FIGS. 6 to 12.

The lower surface of the top ring 4 which is the substrate holding portion communicates with the vacuum line L1, and the top ring 4 is configured to hold the wafer W on the lower surface by vacuum suction. Therefore, the lower surface of the top ring 4 corresponds to the substrate holding surface 4a described above.

The top ring 4 is connected to a top ring shaft 156, and the top ring shaft 156 is moved up and down by a vertical movement mechanism (not shown) installed on the top ring head 158. By moving the top ring shaft 156 up and down, the entire top ring 4 is moved up and down with respect to the top ring head 158 as shown by an arrow, and is positioned. Further, the top ring shaft 156 is rotated by a rotation mechanism (not shown) installed in the top ring head 158. Therefore, the top ring 4 rotates about its own axis as indicated by the arrow as the top ring shaft 156 rotates.

The top ring head 158 is configured to be rotatable around the head arm shaft 157, and the top ring 4 holding the wafer W on the lower surface is a polishing table 153 from the receiving position of the wafer W due to the rotation of the top ring head 158. Moved upwards. Then, the top ring 4 is lowered to press the wafer W against the polishing surface 152a of the polishing pad 152. At this time, the top ring 4 and the polishing table 153 are rotated, respectively, and the polishing liquid (liquid) is supplied onto the polishing pad 152 from the polishing liquid supply unit 155 provided above the polishing table 153. In this way, the wafer W is brought into sliding contact with the polishing surface 152a of the polishing pad 152 to polish the surface of the wafer W.

When the polishing of the surface of the wafer W is completed, the top ring 4 holds the wafer on its lower surface and is raised. At this time, the gas-liquid two-phase flow composed of the polishing liquid adhering to the surface of the wafer W, the polishing liquid remaining on the polishing surface 152a of the polishing pad 152, and the atmosphere is sucked into the vacuum primary line L2 of the vacuum line L1. As described above, the gas-liquid two-phase flow sucked into the vacuum primary line L2 of the vacuum line L1 is separated into a gas (air) and a liquid (polishing liquid) in the gas-liquid separation tank 16. The polishing liquid separated from the gas-liquid two-phase flow is stored in the gas-liquid separation tank 16.

Also in this embodiment, the control unit 9 executes the drainage process of discharging the liquid from the gas-liquid separation tank 16 based on the signal output from the low liquid level sensor 73. More specifically, after the polishing of the surface of the wafer W is completed, the control unit 9 confirms whether or not a signal is output from the low liquid level sensor 73 (see step 6 in FIG. 7). When a signal is output from the low liquid level sensor 73, the control unit 9 opens the drain valve 70 and discharges the liquid from the gas-liquid separation tank 16 (see step 7 in FIG. 7). On the other hand, when no signal is output from the low liquid level sensor 73, the next wafer W is held by the top ring 4 (see step 2 in FIG. 7), and polishing processing (board processing) is executed (FIG. 7). See step 3 of 7).

Further, during the drainage process, the control unit 9 monitors whether or not the drainage process is reliably executed. More specifically, the control unit 9 stores the upper limit value T1 with respect to the execution time of the drainage process in advance, and compares the upper limit value T1 with the elapsed time T2 counted after opening the drain valve 70. (See step 8 in FIG. 7). If the output from the low liquid level sensor 73 is stopped before the elapsed time T2 reaches the upper limit value T1, the control unit 9 determines that the drainage process has been performed reliably. In this case, the control unit 9 ends the drainage process (see step 9 in FIG. 7). When the drainage process is completed, the control unit 9 returns to step 1, holds the next wafer W with the top ring 4, and polishes the surface of the wafer W.

As described above, also in the present embodiment, the control unit 9 executes the drainage process of discharging the liquid from the gas-liquid separation tank 16 only when the low liquid level sensor 73 detects the liquid level. That is, if the low liquid level sensor 73 does not detect the liquid level, the control unit 9 starts the polishing process of the next wafer W without executing the drainage process. As a result, the throughput of substrate processing can be improved. Further, since the control unit 9 can monitor whether or not the drainage treatment is reliably performed based on the output signal of the low liquid level sensor 73, the wafer W can be effectively prevented from being disposed of. be able to.

Although not shown, the substrate holding device 3 of the polishing device shown in FIG. 22 may have two gas-liquid separation units 10a and 10b described with reference to FIG. In this case, the control unit 9 introduces a gas-liquid two-phase flow based on a signal output from the first intermediate liquid level sensor 76a (or the second intermediate liquid level sensor 76b) during polishing of the wafer W. The gas-liquid separation tank is switched from the first gas-liquid separation tank 16a (or the second gas-liquid separation tank 16b) to the second gas-liquid separation tank 16b (or the first gas-liquid separation tank 16a) (step of FIG. 14). 6). Further, the control unit 9 executes a drainage process for discharging the polishing liquid accumulated in the first gas-liquid separation tank 16a (see step 7 in FIG. 14).

As described above, the substrate holding device 3 described with reference to FIG. 6 or 13 can be used as the substrate holding device for holding the substrate to which the liquid is supplied by vacuum adsorption. Although not shown, the substrate holding device 3 of the cleaning device for cleaning the substrate by supplying a cleaning liquid to the substrate vacuum-adsorbed on the substrate holding surface is described with reference to FIG. 6 or 13. May be used.

The above-described embodiment is described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention belongs to carry out the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is construed in the broadest range according to the technical idea defined by the claims.

1A-1D polishing head assembly (board processing unit)
2A to 2D polishing tape supply mechanism 3 Substrate holding device 4 Holding stage (board holding part)
9 Control unit 10 Gas-liquid separation unit 16 Gas-liquid separation tank 36 Upper supply nozzle 37 Lower supply nozzle 70 Drain valve 71 High liquid level sensor 72 Liquid level detection piping 73 Low liquid level sensor 75 Communication valve 76 Intermediate liquid level sensor 77 Vacuum source Valve 78 Gas supply valve 79 Extruded gas supply valve 80 Flow regulator L1 Vacuum line L2 Vacuum primary line L3 Vacuum secondary line L4 Gas supply line L5 Discharge line L6 Extrusion line L7 Purge line

Claims (9)

A substrate holding portion having a substrate holding surface for holding a substrate to which a liquid is supplied by vacuum adsorption,
A vacuum line that communicates the substrate holding surface with the vacuum source,
At least one gas-liquid separation unit that separates the liquid from the gas-liquid two-phase flow sucked into the vacuum line from the substrate holding surface.
A control unit that controls the operation of the substrate holding unit and the gas-liquid separation unit is provided.
The gas-liquid separation unit
The gas-liquid separation tank arranged in the vacuum line and
A discharge line for discharging the liquid accumulated in the gas-liquid separation tank and
The drain valve arranged in the discharge line and
A high liquid level sensor capable of detecting the liquid level in the gas-liquid separation tank and
A low liquid level sensor capable of detecting the liquid level of the gas-liquid separation tank lower than the high liquid level sensor,
A liquid level detection pipe connected to the gas-liquid separation tank and in which the high liquid level sensor and the low liquid level sensor are arranged,
An extrusion line connected to the gas-liquid separation tank and
A purge line that branches off from the extrusion line and is connected to the liquid level detection pipe is provided.
The control unit controls the opening / closing operation of the drain valve based on the output signal of the low liquid level sensor .
A substrate holding device, characterized in that a pressurized gas that pushes a liquid accumulated in the gas-liquid separation tank to the discharge line is supplied to the gas-liquid separation tank via the extrusion line. The substrate holding device according to claim 1 , further comprising a flow rate regulator arranged in the purge line and adjusting the flow rate of the pressurized gas flowing through the purge line. The at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit.
The first gas-liquid separation unit further includes an intermediate liquid level sensor capable of detecting a liquid level between the liquid level detected by the high liquid level sensor and the liquid level detected by the low liquid level sensor.
When the control unit receives the output signal from the intermediate liquid level sensor, the gas-liquid separation tank into which the gas-liquid two-phase flow is introduced is introduced from the gas-liquid separation tank of the first gas-liquid separation unit. The substrate holding device according to claim 1, wherein the second gas-liquid separation unit is switched to a gas-liquid separation tank. A board holding device that holds the board and
A liquid supply unit that supplies liquid to the substrate held by the substrate holding device, and
A substrate processing unit that processes the substrate held by the substrate holding device, and a substrate processing unit.
The substrate holding device, the liquid supply unit, and a control unit for controlling the operation of the substrate processing unit are provided.
The substrate holding device has a substrate holding portion having a substrate holding surface for holding the substrate by vacuum suction, a vacuum line for communicating the substrate holding surface with a vacuum source, and an inflow from the substrate holding surface via the vacuum line. It has at least one gas-liquid separation unit that separates the liquid from the gas-liquid two-phase flow.
The gas-liquid separation unit includes a gas-liquid separation tank arranged in the vacuum line, a discharge line for discharging the liquid accumulated in the gas-liquid separation tank, a drain valve arranged in the discharge line, and the gas-liquid separation unit. A high liquid level sensor capable of detecting the liquid level in the separation tank, a low liquid level sensor capable of detecting the liquid level in the gas-liquid separation tank lower than the high liquid level sensor, and a low liquid level sensor capable of detecting the liquid level in the gas-liquid separation tank are connected to the gas-liquid separation tank. The liquid level detection pipe in which the high liquid level sensor and the low liquid level sensor are arranged, an extrusion line connected to the gas-liquid separation tank, and a branch from the extrusion line are connected to the liquid level detection pipe. Has a purge line and
The control unit controls the opening / closing operation of the drain valve based on the output signal of the low liquid level sensor .
A substrate processing apparatus characterized in that a pressurized gas that pushes a liquid accumulated in the gas-liquid separation tank to the discharge line is supplied to the gas-liquid separation tank via the extrusion line. The at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit.
The first gas-liquid separation unit further includes an intermediate liquid level sensor capable of detecting a liquid level between the liquid level detected by the high liquid level sensor and the liquid level detected by the low liquid level sensor.
When the control unit receives the output signal from the intermediate liquid level sensor, the gas-liquid separation tank into which the gas-liquid two-phase flow is introduced is introduced from the gas-liquid separation tank of the first gas-liquid separation unit. The substrate processing apparatus according to claim 4 , wherein the second gas-liquid separation unit is switched to a gas-liquid separation tank. The substrate is held on the substrate holding surface by vacuum adsorption,
Processing the substrate while supplying the liquid to the substrate,
A gas-liquid separation tank provided in at least one gas-liquid separation unit separates the liquid from the gas-liquid two-phase flow sucked from the substrate holding surface.
The liquid level in the gas-liquid separation tank is a low liquid level capable of detecting a liquid level lower than that of the high liquid level sensor and the high liquid level sensor arranged in the liquid level detection pipe connected to the gas-liquid separation tank. Monitor with a sensor,
After the processing of the substrate is completed, the drainage treatment for discharging the liquid from the gas-liquid separation tank is executed only when a signal is output from the low liquid level sensor.
During the liquid drainage treatment, a pressurized gas is supplied to the gas-liquid separation layer via an extrusion line connected to the gas-liquid separation layer, and the liquid accumulated in the gas-liquid separation tank is discharged to the gas-liquid separation tank. A substrate processing method characterized by supplying the pressurized gas to a purge line branched from the extrusion line and connected to the liquid level detection pipe. The at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit.
During the processing of the substrate, the liquid level in the first gas-liquid separation tank is set between the liquid level detected by the high liquid level sensor and the liquid level detected by the low liquid level sensor. Monitor with a detectable intermediate liquid level sensor,
When a signal is output from the intermediate liquid level sensor, the gas-liquid separation tank that separates the liquid from the gas-liquid two-phase flow is moved from the gas-liquid separation tank of the first gas-liquid separation unit to the second gas-liquid separation unit. The substrate processing method according to claim 6 , wherein the gas-liquid separation tank is switched to. Steps to hold the substrate on the substrate holding surface by vacuum suction,
The step of processing the substrate while supplying the liquid to the substrate,
A step of separating the liquid from the gas-liquid two-phase flow sucked from the substrate holding surface in a gas-liquid separation tank provided in at least one gas-liquid separation unit.
The liquid level in the gas-liquid separation tank is a low liquid level capable of detecting a liquid level lower than that of the high liquid level sensor and the high liquid level sensor arranged in the liquid level detection pipe connected to the gas-liquid separation tank. Steps to monitor with sensors and
A step of executing a drainage treatment for discharging the liquid from the gas-liquid separation tank only when a signal is output from the low liquid level sensor after the processing of the substrate is completed.
During the liquid drainage treatment, a pressurized gas is supplied to the gas-liquid separation layer via an extrusion line connected to the gas-liquid separation layer, and the liquid accumulated in the gas-liquid separation tank is pushed out to the discharge line. At the same time, a non-temporary computer-readable program recording a program for causing the computer to execute the step of supplying the pressurized gas to the purge line branched from the extrusion line and connected to the liquid level detection pipe. recoding media. The at least one gas-liquid separation unit is a first gas-liquid separation unit and a second gas-liquid separation unit.
While executing the step of processing the substrate, the liquid level in the first gas-liquid separation tank is the liquid level detected by the high liquid level sensor and the liquid detected by the low liquid level sensor. The step of monitoring the liquid level between the surfaces with an intermediate liquid level sensor that can detect it,
When a signal is output from the intermediate liquid level sensor, the gas-liquid separation tank that separates the liquid from the gas-liquid two-phase flow is moved from the gas-liquid separation tank of the first gas-liquid separation unit to the second gas-liquid separation unit. The computer-readable recording medium according to claim 8 , wherein the step of switching to the gas-liquid separation tank is further executed by a computer.

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