Grinding Equipment

Abstract

To provide a grinding device configured so that even one operator can deal with detachment of a wafer from a holding surface of a chuck table, due to a trouble or the like in the middle of grinding.SOLUTION: A chuck table 6 comprises: suction force generating means 120 that is connected to a suction source 122 through a first valve 124 and generates suction force V on a holding surface 61; and fluid jetting means 130 that is connected to a fluid supply source 132 through a second valve 136 and jets fluid P onto the holding surface 61. An external force detecting sensor 110 that detects application of external force to the chuck table 6 is connected to the chuck table 6. In a state where grinding is interrupted and grinding means 3 and 4 are separated from the chuck table 6 by lifting means 39 and 49, when external force is applied to the chuck table 6 and a detection signal S is outputted from the external force detecting sensor 110 to control means 100, the control means 100 closes the first valve 124 and opens the second valve 136 to allow the fluid P to be jetted from the holding surface 61 of the chuck table 6, so that a work-piece W is floated from the holding surface 61.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a grinding device for grinding a workpiece. [Background technology]

[0002] A wafer has a number of devices such as ICs and LSIs formed on its front surface along division lines, and the back surface is ground by a grinding machine to form the wafer into the desired thickness. The wafer is then divided into individual device chips by a dicing machine and laser processing machine. These chips are then used in electrical devices such as mobile phones and personal computers.

[0003] The grinding apparatus includes a chuck table having a holding surface for holding a workpiece, grinding means having a rotatable grinding wheel with grinding stones arranged in a ring shape for grinding the workpiece held on the holding surface, lifting means for moving the grinding means toward and away from the chuck table, grinding water supply means for supplying grinding water to the grinding stones and the workpiece held on the chuck table, and control means, and is capable of grinding the workpiece (e.g., a semiconductor wafer) with high precision. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-101913 A Summary of the Invention [Problem to be solved by the invention]

[0005] When a trouble occurs during grinding using the above-mentioned grinding device (for example, when the load current value of the motor constituting the grinding means shows an abnormality), it becomes necessary to stop the operation of the grinding device midway and remove the wafer being ground from the chuck table in order to investigate the cause of the trouble. In this case, a touch panel arranged on the grinding device is used to instruct the control means (computer) to eject a fluid from the holding surface of the chuck table. Based on this instruction, an instruction signal is issued from the control means to the fluid ejection means, and a fluid, for example, a mixture of water and air, is ejected from the holding surface of the chuck table, and the workpiece held on the holding surface floats up. Since the workpiece that floats up from the holding surface of the chuck table may leave the holding surface of the chuck table together with the ejected fluid and fall into the surroundings, when performing this work, an operator who operates the operation panel of the grinding device to give instructions and another operator who waits in front of the chuck table to catch the workpiece that floats up from the holding surface of the chuck table before it falls are required, which causes a problem of poor productivity.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its main technical object is to provide a grinding apparatus that allows even a single operator to handle the removal of a wafer from the holding surface of a chuck table due to a problem or the like that occurs during grinding. [Means for solving the problem]

[0007] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a grinding apparatus comprising a chuck table having a holding surface for holding a workpiece, grinding means having a rotatable grinding wheel on which grinding stones for grinding the workpiece held on the holding surface are arranged in an annular shape, lifting means for moving the grinding means towards and away from the chuck table, grinding water supplying means for supplying grinding water to the grinding stone and the workpiece held on the chuck table, and control means, wherein the chuck table is provided with suction force generating means connected to a suction source via a first valve and generating a suction force on the holding surface, and fluid jetting means connected to a fluid supply source via a second valve and jetting fluid onto the holding surface, an external force detection sensor is connected to the chuck table for detecting the application of an external force to the chuck table, and when grinding is interrupted and the grinding means is moved away from the chuck table by the lifting means, The control means is set to a mode in which an operator removes a wafer from the chuck table. In this state, By operator A grinding device is provided in which, when an external force is applied and a detection signal is output from the external force detection sensor to the control means, the control means closes the first valve and opens the second valve to eject the fluid from the holding surface of the chuck table, thereby lifting the workpiece from the holding surface.

[0008] It is preferable that the fluid supply source includes a water supply source and an air supply source, and that a mixed fluid of water and air is ejected from the holding surface when the second valve is opened. It is also preferable that the external force detection sensor is a pressure sensor, and that the pressure sensor outputs a detection signal when the chuck table is pressed from above. Effect of the Invention

[0009] The grinding apparatus of the present invention is a grinding apparatus comprising a chuck table having a holding surface for holding a workpiece, grinding means having a rotatable grinding wheel on which grinding stones for grinding the workpiece held on the holding surface are arranged in an annular shape, lifting means for moving the grinding means towards and away from the chuck table, grinding water supplying means for supplying grinding water to the grinding stone and the workpiece held on the chuck table, and control means, wherein the chuck table is provided with suction force generating means connected to a suction source via a first valve for generating a suction force on the holding surface, and fluid ejecting means connected to a fluid supply source via a second valve for ejecting fluid on the holding surface, and an external force detection sensor is connected to the chuck table for detecting the application of an external force to the chuck table, and when grinding is interrupted and the grinding means is moved away from the chuck table by the lifting means, The control means is set to a mode in which an operator removes a wafer from the chuck table. In this state, By operator When an external force is applied and a detection signal is output from the external force detection sensor to the control means, the control means closes the first valve and opens the second valve to spray the fluid from the holding surface of the chuck table and lift the workpiece from the holding surface. Therefore, even if a problem occurs during grinding processing and it becomes necessary to stop operation of the grinding apparatus and remove the wafer being ground from the chuck table, the work can be performed by one person, and there is no longer a need to have one operator operate the grinding apparatus while another operator waits to grab the wafer as it lifts up from the chuck table, as was the case in the conventional method, thereby solving the problem of poor productivity. [Brief description of the drawings]

[0010] [Figure 1] 1 is an overall perspective view of a grinding device according to an embodiment of the present invention; [Diagram 2] 2 is a conceptual diagram showing an overview of a suction force generating means and a fluid ejecting means disposed on a chuck table of the grinding machine shown in FIG. 1. [Diagram 3] FIG. 2A is a perspective view showing a manner in which a dicing tape is adhered to a wafer, and FIG. 2B is a perspective view showing a manner in which the wafer is held on a chuck table. [Figure 4] 2A is a perspective view showing a state in which grinding is performed by the grinding apparatus shown in FIG. 1, and FIG. 2B is a perspective view showing a state in which the grinding means is retracted from the chuck table. FIG. [Diagram 5] 11 is a conceptual diagram showing an operation of applying an external force to the chuck table to lift the wafer from the chuck table. [Figure 6] 4 is a flowchart of a control program stored in control means 100. [Figure 7] FIG. 11 is a side view showing a state in which the wafer is floated from the chuck table. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a grinding device constructed based on the present invention will be described in detail with reference to the accompanying drawings.

[0012] Fig. 1 shows a perspective view of a grinding device 1 according to this embodiment. The grinding device 1 includes a device housing 2 having a substantially rectangular parallelepiped shape. In Fig. 1, a support wall 21 is erected on the rear end side of the device housing 2. Two pairs of guide rails 22, 22 and 23, 23 extending in the vertical direction are provided on the inner surface of this support wall 21. A rough grinding unit 3 as a rough grinding means is attached to one of the guide rails 22, 22 so as to be movable in the vertical direction, and a finish grinding unit 4 as a finish grinding means is attached to the other guide rails 23, 23 so as to be movable in the vertical direction.

[0013] The rough grinding unit 3 comprises a unit housing 31, a wheel mount 33 arranged at the lower end of a rotating shaft 32 supported for free rotation by the unit housing 31, a rough grinding wheel 34 attached to the wheel mount 33 and having a plurality of grinding wheels 35 arranged in a ring shape on its underside, an electric motor 36 attached to the upper end of the unit housing 31 for rotating the wheel mount 33 in the direction indicated by arrow R1, and a movable base 38 supporting the unit housing 31 via a support member 37.

[0014] The moving base 38 is provided with a guided groove that slidably fits into the guide rails 22, 22 provided on the support wall 21, and the rough grinding unit 3 is supported so as to be movable in the vertical direction. The grinding device 1 in the illustrated embodiment is provided with a grinding feed mechanism 39 arranged as a lifting means for lifting the moving base 38 of the rough grinding unit 3 along the guide rails 22, 22. The grinding feed mechanism 39 is provided with a male screw rod 391 that is arranged in the vertical direction parallel to the guide rails 22, 22 and rotatably supported on the support wall 21, a pulse motor 392 for rotating the male screw rod 391, and a female screw block (not shown) that is attached to the moving base 38 and screws into the male screw rod 391. The male screw rod 391 is driven forward and reverse by the pulse motor 392 to move the rough grinding unit 3 in the Z-axis direction (vertical direction).

[0015] The finish grinding unit 4 is also configured in a manner substantially similar to the rough grinding unit 3, and comprises a unit housing 41, a wheel mount 43 arranged at the lower end of a rotating shaft 42 supported rotatably on the unit housing 41, a finish grinding wheel 44 attached to the wheel mount 43 and having a plurality of grinding wheels 45 arranged in a ring shape on its underside, an electric motor 46 attached to the upper end of the unit housing 41 for rotating the wheel mount 43 in the direction indicated by arrow R2, and a movable base 48 supporting the unit housing 41 via a support member 47.

[0016] The movable base 48 is provided with a guided groove that slidably fits into the guide rails 23, 23 provided on the support wall 21, and the finish grinding unit 4 is supported so as to be movable in the vertical direction. The grinding device 1 in the illustrated embodiment is provided with a grinding feed mechanism 49 arranged as a lifting means for lifting and lowering the movable base 48 of the finish grinding unit 4 along the guide rails 23, 23. The grinding feed mechanism 49 is provided with a male screw rod 491 that is arranged in the vertical direction parallel to the guide rails 23, 23 and rotatably supported on the support wall 21, a pulse motor 492 for rotating the male screw rod 491, and a female screw block (not shown) that is attached to the movable base 48 and screws into the male screw rod 491, and the male screw rod 491 is driven forward and reverse by the pulse motor 492 to move the finish grinding unit 4 in the Z-axis direction (vertical direction).

[0017] A grinding water supplying means 10 is connected to the rotating shaft ends 32a, 42a of the rotating shaft 32, 42 rotated by the electric motor 36 and the electric motor 46, for supplying grinding water L to the grinding wheels 35, 45 and the workpiece held on the chuck table 6 described later. The grinding water supplying means 10 includes a grinding water tank 10a incorporating a pressure pump (not shown), a grinding water supplying path 10d having an opening / closing valve 10b, and a grinding water supplying path 10e having an opening / closing valve 10c, and supplies the grinding water L pumped from the grinding water tank 10a to the rotating shaft ends 32a, 42a, and sprays it horizontally from the center of the lower end faces of the rough grinding wheel 34 and the finish grinding wheel 44 toward the grinding wheels 35, 45. In FIG. 1, for convenience of explanation, the grinding water supply means 10 is shown outside the device housing 2, but it may be accommodated inside the device housing 2.

[0018] The grinding device 1 in the illustrated embodiment includes a turntable 5 disposed in front of the support wall 21 so as to be substantially flush with the upper surface of the device housing 2. The turntable 5 is formed in a relatively large-diameter disk shape, and is rotated appropriately in the direction indicated by the arrow R3 by a rotation drive mechanism (not shown). In the illustrated embodiment, the turntable 5 is provided with three chuck tables 6 arranged at angles of 120 degrees, and each chuck table 6 is provided with a rotation drive means (described later) and is configured to be rotatable in the direction indicated by the arrow R4. The chuck table 6 includes a suction chuck 61 formed in a disk shape from a breathable member and forming the holding surface of the chuck table 6, and a frame 62 surrounding the suction chuck 61.

[0019] The three chuck tables 6 arranged on the turntable 5 are moved sequentially from workpiece loading / unloading area A → rough grinding area B → finish grinding area C → workpiece loading / unloading area A by rotating the turntable 5 in the direction indicated by arrow R3.

[0020] The illustrated grinding apparatus 1 comprises a first cassette 7 arranged on one side of the workpiece carry-in / out area A and accommodating wafers W, which are workpieces before grinding, a second cassette 8 arranged on the other side of the workpiece carry-in / out area A and accommodating wafers W after grinding, a temporary placement means 9 arranged between the first cassette 7 and the workpiece carry-in / out area A for aligning the center of the workpiece, a cleaning means 11 arranged between the workpiece carry-in / out area A and the second cassette 8, and a cleaning means 12 arranged between the workpiece carry-in / out area A and the second cassette 8. The workpiece transport means 12 transports the wafer W that has been ground to the temporary placement means 9 and transports the wafer W that has been cleaned by the cleaning means 11 to the second cassette 8, a first transport means 13 transports the wafer W that has been placed on the temporary placement means 9 and centered onto the chuck table 6 positioned in the workpiece carry-in / out area A, and a second transport means 14 transports the wafer W after grinding that is placed on the chuck table 6 positioned in the workpiece carry-in / out area A to the cleaning means 11. Note that the present invention is not limited to the above-mentioned configuration, and for example, a single transport means serving as both the first transport means 13 and the second transport means 14 may be provided.

[0021] At the front side of the equipment housing 2, where the workpiece transport means 12 is arranged, there are provided an operation panel 15 for instructing the grinding work and specifying the processing conditions, and a display monitor 16 for displaying the status during grinding and having a touch panel function so that appropriate work instructions can be given.

[0022] The configuration of the chuck table 6 will be described in more detail with reference to FIG. 2. The configuration described below is common to the three chuck tables 6 arranged on the turntable 5. FIG. 2 shows a part of the turntable 5 in cross section, and also shows the chuck table 6 as viewed from the side. The frame 62 of the chuck table 6 is connected to a drive shaft 64 of an electric motor 63 and is rotated at a desired rotation speed. The suction chuck 61 of the chuck table 6 is connected to the suction source 122 via a first valve 124 arranged in a communication passage 126, and includes a suction force generating means 120 that generates a suction force V on the suction chuck 61 via a passage in the drive shaft 64. The suction chuck 61 is connected to a fluid supply source 132 via a second valve 136 arranged in a communication passage 138, and includes a fluid ejection means 130 that ejects a fluid P onto the suction chuck 61. In this embodiment, the communication passage 138 is connected to the communication passage 126, which is connected to a rotary joint 65 disposed at a lower end 64a of a drive shaft 64 of the electric motor 63. The suction force generating means 120 opens the first valve 124 and closes the second valve 136 to generate a suction force V on the suction chuck 61 constituting a holding surface for holding the workpiece through the rotary joint 65. The fluid jetting means 130 closes the first valve 124 and opens the second valve 136 to jet a fluid P to the suction chuck 61 through the rotary joint 65. The fluid supply source 132 in this embodiment is composed of an air supply source 132a that jets air A and a water supply source 132b that jets water L, and jets a fluid P in which the air A and the water L are mixed. The water supply source 132b for spouting the water L may also be used as the grinding water supply means 10 described above.

[0023] A plurality of (e.g., three or more) pressure sensors 110 are arranged as external force detection sensors on the outer circumferential underside of a support plate 631 that supports an electric motor 63 that rotates and drives the chuck table 6, and the chuck table 6 is supported on the turntable 5 via the plurality of pressure sensors 110. The pressure sensor 110 may be, for example, a sensor made of a piezoelectric element. When a pressing force is applied from above to the chuck table 6 with a finger or the like and a certain amount of force (e.g., 1 N or more) is applied, it is determined that an external force has been applied to the chuck table 6 and a detection signal is output from the pressure sensor 110.

[0024] The illustrated grinding device 1 includes a control means 100. The control means 100 includes a central processing unit (CPU) that performs calculations according to a control program, a read-only memory (ROM) that stores the control program and the like, a readable / writable random access memory (RAM) that serves as storage means for storing calculation results and the like, and an input interface and an output interface (all of which are not shown). The control means 100 thus configured is connected to the grinding water supply means 10, the operation panel 15, the display monitor 16, the pressure sensor 110, the first valve 124, the second valve 136, and other operating parts (not shown).

[0025] The illustrated grinding device 1 has substantially the configuration described above, and the effects of the grinding device 1 of this embodiment will be described below.

[0026] In the grinding apparatus 1 of this embodiment, the wafer W stored in the first cassette 7 as the workpiece has a plurality of devices D formed on its surface Wa, partitioned by planned division lines, as shown in FIG. 3(a), and a dicing tape T is attached to the surface Wa of the wafer W.

[0027] When the first cassette 7 containing the wafer W is set in the grinding device 1 shown in FIG. 1, the turntable 5 is operated to position the chuck table 6 on which the wafer W is not held in the workpiece carry-in / out area A, or to position the chuck table 6 on which the wafer W has been carried out after the finish grinding process in the workpiece carry-in / out area A. Next, the workpiece transport means 12 is operated to carry out the unprocessed wafer W from the first cassette 7 and place it on the temporary placement means 9 to perform centering of the wafer W. The wafer W after centering is transported using the first transport means 13, and placed on the suction chuck 61 of a predetermined chuck table 6 positioned in the workpiece carry-in / out area A with the dicing tape T side facing downward and the back surface Wb side of the wafer W facing upward, as shown in FIG. 3(b). Then, the suction source 122 of the suction force generating means 120 described based on FIG. 2 is operated, the first valve 124 is opened, and the second valve 136 is closed to generate a suction force V on the suction chuck 61 constituting the holding surface of the chuck table 6, thereby suction-holding the wafer W.

[0028] Once the wafer W has been suction-held on a designated chuck table 6, the turntable 5 is rotated in the direction indicated by the arrow R3 in FIG. 1, and the chuck table 6, which is suction-holding the unprocessed wafer W described above, is moved from the workpiece loading / unloading area A toward the rough grinding area B.

[0029] When the chuck table 6 is positioned in the rough grinding area B, the rough grinding step described below is performed. More specifically, as shown in FIG. 4(a), the wafer W held on the chuck table 6 is positioned at a position where the grinding wheel 35 arranged in an annular shape on the lower surface of the rough grinding wheel 34 passes over the entire back surface of the wafer W. Next, the chuck table 6 is rotated in the direction indicated by the arrow R4 in FIG. 4(a) at, for example, 300 rpm, and at the same time, the rough grinding unit 3 is operated to rotate the rough grinding wheel 34 in the direction indicated by the arrow R1 in the figure at, for example, 6000 rpm. Then, the grinding feed mechanism 39 is operated to lower the rough grinding unit 3 in the direction indicated by the arrow R5 in FIG. 4(a), and the grinding wheel 35 is brought into contact with the back surface Wb of the wafer W from above, and is fed for grinding at a grinding feed speed of, for example, 1.0 μm / sec. At this time, the grinding water supply means 10 described based on FIG. 1 is operated to supply grinding water L from the underside of the rough grinding wheel 34 toward the grinding stone 35 and the back surface Wb of the wafer W, which is the workpiece.

[0030] Although details will not be explained, when the above-mentioned rough grinding process is performed, if a wafer W after undergoing the rough grinding process is positioned in the adjacent finish grinding processing area C, the finish grinding unit 4 can be operated at the same time as the above-mentioned rough grinding process is performed, and the finish grinding wheel 44 can be brought into contact with the wafer W to perform the finish grinding process.

[0031] Here, in the above-mentioned grinding apparatus 1, it is assumed that a trouble occurs during grinding in which the load current value of the electric motor 36 constituting the rough grinding unit 3 arranged as the rough grinding means indicates an abnormal value, and the trouble is detected by the control means 100. In this case, the control means 100 notifies the outside that the trouble has occurred by sounding a buzzer arranged in the grinding apparatus 1, blinking a red lamp, or the like, and raises (retracts) the rough grinding unit 3 in the direction indicated by the arrow R6 as shown in Fig. 4(b), thereby bringing the operation of the grinding apparatus 1 to an emergency stop.

[0032] An operator who notices a problem with the grinding apparatus 1 operates the display monitor 16 of the grinding apparatus 1 (or the operation panel 15) to confirm the cause of the problem and switch to the wafer removal mode as shown in FIG. 5 in order to recover from the current situation. The switch to the wafer removal mode is premised on the fact that grinding is interrupted and the grinding means (rough grinding unit 3, finish grinding unit 4) are moved away from the chuck table 6 by the lifting means (grinding feed mechanisms 39, 49), and the control means 100 confirms this premise before switching to the wafer removal mode. When the mode is switched to the wafer removal mode, the control means 100 executes a flow chart 140 shown in FIG. 6. The operation of the grinding apparatus 1 when the flow chart 140 is executed will be described below.

[0033] When the flow chart 140 is executed, first, in step S1, an external force is applied to the chuck table 6, and it is determined whether the pressure sensor 110 receives an external force equal to or greater than a predetermined value (for example, 1 N or greater), that is, whether the pressure sensor 110 detects an external force. If the pressure sensor 110 does not detect an external force, the process does not proceed to step S2, and step S1 is repeated. Here, the operator enters the inside of the grinding apparatus 1, and as shown in FIG. 5, in order to apply an external force to the chuck table 6, the operator uses his / her finger F to push a predetermined position on the chuck table 6, for example, the frame body 62, from above to below, thereby applying an external force of, for example, 1 N or greater to the chuck table 6. This external force is detected by the pressure sensor 110, which transmits a detection signal S to the control means 100 to notify the control means 100 that an external force has been applied. When the control means 100 receives the detection signal S, the process proceeds to step S2, where the first valve 124 of the suction force generating means 120 is closed, and the generation of the suction force V acting on the suction chuck 61 of the chuck table 6 is stopped.

[0034] Following step S2, the process proceeds to step S3, where the second valve 136 of the fluid jetting means 130 is opened. In a factory in which the grinding apparatus 1 is installed, the air source 132a and the water source 132b are normally in operation at all times, so that by opening the second valve 136, a fluid P containing a mixture of air A and water L is supplied to the communication passage 138 as shown in Fig. 5. The fluid P supplied to the communication passage 138 flows into the communication passage 126, and is supplied via the rotary joint 65 and the lower end 64a of the drive shaft 64 of the electric motor 63, and is jetted out of the suction chuck 61 as shown in Fig. 7.

[0035] 7, the above-mentioned fluid P is ejected from the suction chuck 61, causing the wafer W that has been sucked and held by the suction chuck 61 to float. Since the operator is in front of the chuck table 6 in order to apply an external force with a finger F to the chuck table 6 to cause the wafer W to float from the suction chuck 61, the operator can easily grasp and take out the wafer W that floats with the ejection of the fluid P.

[0036] As described above, after step S3 is performed, the control means 100 judges whether or not a predetermined time (for example, 5 seconds) has elapsed since the second valve 136 was opened. If 5 seconds have not elapsed, step S4 is repeated to continue the operation of ejecting the fluid P from the suction chuck 61. If it is judged in step S4 that a predetermined time has elapsed since the second valve 136 was opened, the process proceeds to step S5, where the second valve 136 is closed. As a result, the ejection of the fluid P from the suction chuck 61 is stopped. After step S5 is performed, the process returns to step S1 (RETURN), and the flow chart 140 is repeatedly performed. As a result, for example, when there are three chuck tables 6 as shown in FIG. 1 and a wafer W is held on each of the three chuck tables 6, the wafer W can be taken out from each of the chuck tables 6.

[0037] As described above, the wafer W is safely removed from the chuck table 6, the cause of the abnormality is confirmed, and if it is confirmed that the grinding process can be resumed, the control means 100 is instructed to end the wafer removal mode (flowchart 140) by operating the display monitor 16, and is also instructed to resume the grinding process.

[0038] According to this embodiment, even if a problem occurs during grinding processing and it becomes necessary to stop the operation of the grinding apparatus 1 and remove the wafer W that is being ground from the chuck table 6, the work can be performed by one person, eliminating the need to provide an operator to operate the grinding apparatus 1 and an operator to grasp the wafer W that floats up from the chuck table 6, as was the case in the conventional method, thereby solving the problem of poor productivity.

[0039] The present invention is not limited to the above embodiment. In the above embodiment, three chuck tables 6 are arranged on the turntable 5, and an example of a grinding device capable of simultaneously performing rough grinding and finish grinding is shown, but the present invention is not limited to this, and can also be applied to a grinding device equipped with only one chuck table. In addition, in the above embodiment, an example is shown in which a fluid P mixed with air A and water L is used as the fluid to be ejected from the chuck table 6, but the present invention is not limited to this, and only water L can be discharged, or other fluids can be mixed. Furthermore, in the above embodiment, an example is shown in which a pressure sensor using a piezoelectric element is used as the external force detection sensor, but the present invention is not limited to this, and for example, a detection means using a strain gauge or a button switch may be used. [Explanation of symbols]

[0040] 1: Grinding device 2: Device housing 21:Supporting wall 22, 23: Guide rail 3: Rough grinding unit 31: Unit housing 32: Rotation axis 33: Wheel mount 34: Rough grinding wheel 35: Grinding wheel 36: Electric motor 37: Support member 38: Mobile base 39: Grinding feed mechanism 4: Finish grinding unit 41: Unit housing 42: Rotation axis 43: Wheel mount 44: Finishing grinding wheel 45: Grinding wheel 46: Electric motor 47: Support member 48: Mobile base 49: Grinding feed mechanism 5: Turntable 6: Chuck table 61: Suction chuck 62: Frame 63: Electric motor 631: Support plate 64: Drive shaft 64a: Bottom end 65: Rotary joint 7: First Cassette 8: Second Cassette 9: Temporary storage means 10: Grinding water supply means 10a: Grinding water tank 10b: Opening and closing valve 10c: Opening and closing valve 10d: Grinding water supply channel 10e: Grinding water supply channel 11: Cleaning method 12:Workpiece conveyance means 13: First conveying means 14: Second conveyance means 15: Operation panel 16: Display monitor 100: Control means 110: Pressure sensor 120: Attraction force generation means 122: Suction source 124: First valve 126: Communication path 130: Fluid ejection means 132: Fluid supply source 132a: Air source 132b: Water source 136: Second valve 138: Communication path A: Air L: Water (grinding water) P:Fluid

Claims

1. A grinding device comprising: a chuck table having a holding surface for holding a workpiece; grinding means having a rotatable grinding wheel on which grinding stones for grinding the workpiece held on the holding surface are arranged in an annular shape; lifting means for moving the grinding means toward and away from the chuck table; grinding water supplying means for supplying grinding water to the grinding stones and the workpiece held on the chuck table; and control means, the chuck table includes a suction force generating means connected to a suction source via a first valve and generating a suction force on the holding surface, and a fluid ejecting means connected to a fluid supply source via a second valve and ejecting a fluid onto the holding surface, An external force detection sensor is connected to the chuck table which detects that an external force is applied to the chuck table, and when grinding is interrupted and the grinding means is moved away from the chuck table by the lifting means and the control means is set to a mode in which the operator removes the wafer from the chuck table, when an external force is applied to the chuck table by the operator and a detection signal is output from the external force detection sensor to the control means, the control means closes the first valve and opens the second valve to spray the fluid from the holding surface of the chuck table, thereby floating the workpiece from the holding surface.

2. 2. The grinding device according to claim 1, wherein the fluid supply source includes a water supply source and an air supply source, and when the second valve is opened, a mixture of water and air is ejected from the holding surface.

3. 3. The grinding apparatus according to claim 1, wherein the external force detection sensor is a pressure sensor, and the pressure sensor outputs a detection signal when the chuck table is pressed from above.

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