Chuck table and grinding device

Abstract

To provide a chuck table which can resolve a problem of contamination of a suction pad caused by the suction pad of transport means suctioning contaminants and a problem of clogging occurring at a porous plate, and to provide a grinding device.SOLUTION: A grinding device 1 is formed including: a chuck table 3 which holds a wafer 10; grinding means 4 which rotatably includes a grinding wheel 42 in which grind stones 43 for grinding the wafer 10 held by the chuck table 3 are annularly arranged; and a grinding water supply means 6 which supplies griding water W to the grind stones 43 and the wafer 10. The chuck table 3 includes: a porous plate 31 having a holding surface 31a which suctions and holds the wafer 10; and a frame body 32 which supports an outer periphery and a bottom surface of the porous plate 31 and transmits a negative pressure and a positive pressure to the holding surface 31a. The frame body 32 is formed with multiple grooves 33 extending from the holding surface 31a side to a side surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a chuck table for holding a wafer and a grinding apparatus for grinding the wafer held on the chuck table. [Background technology]

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

[0003] The grinding device is configured to include a chuck table that holds the wafer, a grinding means that has a rotatable grinding wheel with grinding stones arranged in a ring shape to grind the wafer held on the chuck table, and a grinding water supply means that supplies grinding water to the grinding stones and the wafer, and can process the wafer to a desired thickness (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-246098 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when a wafer held on a chuck table is ground in the above-described grinding apparatus, contaminants (grinding debris) generated during grinding become mixed with the grinding water supplied during grinding and accumulate on the outer periphery of the chuck table, and when the wafer is carried out from the chuck table, the suction pad of the transport means sucks up the contaminants, causing the suction pad to become contaminated.

[0006] Furthermore, when the chuck table sucks and holds the next wafer, the grinding water containing contaminants is sucked in, causing clogging of the porous plate that constitutes the chuck table.

[0007] The present invention has been made in consideration of the above facts, and its main technical object is to provide a chuck table and a grinding device that can solve the problem of the suction pad of the conveying means sucking in the contaminants and becoming contaminated, and the problem of the porous plate becoming clogged. [Means for solving the problem]

[0008] In order to solve the above-mentioned main technical problem, according to the present invention, a chuck table for holding a wafer comprises a porous plate having a holding surface for suction-holding the wafer, and a pressure adjusting device for supporting the outer periphery and bottom surface of the porous plate and transmitting negative pressure and positive pressure to the holding surface. Frame and a frame body, and a plurality of grooves are formed in the frame body from the holding surface side to the side surface. The upper surface of the holding surface and the upper surface of the frame are formed flush with each other. A chuck table is provided. Also according to the present invention, there is provided a chuck table for holding a wafer, comprising: a porous plate having a holding surface for suction-holding a wafer; and a frame for supporting the outer periphery and bottom surface of the porous plate and transmitting negative and positive pressure to the holding surface, wherein the frame has a plurality of grooves formed therein from the holding surface side to the side surface, the grooves being grooves for allowing grinding water that has flowed over the wafer held on the holding surface to flow down. Also according to the present invention, there is provided a chuck table for holding a wafer, comprising: a porous plate having a holding surface for suction-holding a wafer; and a frame for supporting the outer periphery and bottom surface of the porous plate and transmitting negative and positive pressure to the holding surface, wherein the frame has a plurality of grooves formed therein that extend from the holding surface side to the side surface and to the lower end of the side surface.

[0009] According to the present invention, there is also provided a grinding apparatus including a chuck table for holding a wafer, grinding means having a rotatable grinding wheel on which grinding stones for grinding the wafer held on the chuck table are arranged in an annular shape, and grinding water supply means for supplying grinding water to the grinding stones and the wafer, The chuck table is any one of the chuck tables described above. A grinding apparatus is provided. [Effects of the Invention]

[0010] The chuck table of the present invention comprises a porous plate having a holding surface for suction-holding a wafer, and a chuck supporting the outer periphery and bottom surface of the porous plate and transmitting negative and positive pressure to the holding surface. FrameSince the frame has a plurality of grooves formed in it from the holding surface to the side surfaces, when the frame is applied to a grinding device, for example, the capillary action in the grooves and the surface tension of the grinding water flowing down the side surfaces of the frame allow the grinding water containing contaminants to smoothly flow down the outer periphery of the chuck table, i.e., from the upper surface of the frame, and the grinding water is prevented from accumulating on the outer periphery of the chuck table. This eliminates the problem of contamination of the suction pad that suctions the wafer when the processed wafer is removed from the chuck table due to the suction pad sucking up contaminants generated during processing.

[0011] In addition, the grinding apparatus of the present invention is a grinding apparatus comprising a chuck table for holding a wafer, a grinding means having a rotatable grinding wheel on which grinding stones are arranged in a ring shape for grinding the wafer held on the chuck table, and a grinding water supply means for supplying grinding water to the grinding stone and the wafer, wherein the chuck table comprises a porous plate having a holding surface for suction-holding the wafer, and a frame body supporting the outer periphery and bottom surface of the porous plate and transmitting negative and positive pressure to the holding surface, and the frame body has a plurality of grooves formed therein extending from the holding surface side to the side surface, so that the capillary action of the grooves formed in the frame body and the surface tension of the grinding water flowing down from the side surface of the frame body allow grinding water mixed with contaminants, etc., to flow smoothly down the outer periphery of the chuck table, i.e., from the top surface of the frame body, preventing it from accumulating on the outer periphery of the chuck table. This eliminates the problem that when the ground wafer is carried out from the chuck table, the suction pad that holds the wafer sucks in contaminants generated during processing, causing the suction pad to become contaminated. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view of a wafer held on a chuck table according to the present embodiment. [Figure 2] 1 is an overall perspective view of a grinding device according to an embodiment of the present invention; [Figure 3] 3 is a perspective view showing a manner in which a wafer is held on a chuck table of the grinding apparatus shown in FIG. 2. FIG. [Figure 4] 3 is a schematic view showing a mode in which a suction source, a water source, and an air supply source are connected to the chuck table shown in FIG. 2. [Figure 5] 3 is a perspective view showing how a wafer is ground in the grinding apparatus shown in FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a chuck table for holding a wafer and a grinding apparatus for grinding a wafer held on the chuck table, which are configured based on the present invention, will be described in detail with reference to the accompanying drawings.

[0014] 1 shows a wafer 10 to be ground while being held on a chuck table 3 of a grinding apparatus 1 (see FIG. 2) of this embodiment. The wafer 10 has a surface 10a on which a plurality of devices 12 are formed and partitioned by planned division lines 14, and a protective tape T is attached to the surface 10a.

[0015] 2 shows an overall perspective view of a grinding apparatus 1 for grinding a wafer 10 according to this embodiment. The grinding apparatus 1 includes at least a chuck table 3 for holding the wafer 10, a grinding means 4 for grinding the back surface 10b of the wafer 10 held on the chuck table 3, a lifting means 5 for lifting the grinding means 4 in the Z-axis direction (up and down direction), and a grinding water supplying means 6 for supplying grinding water W to the grinding stone 43 of the grinding means 4 and the wafer 10.

[0016] 2 and 3, the chuck table 3 includes a porous plate 31 having a holding surface 31a that holds the wafer 10 by suction, and a frame 32 that supports the outer periphery and bottom surface of the porous plate 31 and transmits negative pressure (negative pressure) and positive pressure (positive pressure) to the holding surface 31a. The porous plate 31 is made of a breathable material. A plurality of grooves 33 are formed around the entire periphery of the frame 32, extending from the holding surface 31a to the side surface. Each groove 33 has a width of, for example, about 1 to 2 mm.

[0017] The chuck table 3 is configured to be rotatable by a rotary drive means (not shown), and is moved to any position in the X-axis direction by an X-axis moving means (not shown) housed inside the device housing 2, for example, to a load / unload position on the front side in the drawing where the wafer 10 is loaded and unloaded, and to a grinding processing position directly below the grinding means 4 where grinding processing is performed.

[0018] As shown in FIG. 4 , the frame 32 is connected to the suction source 7 via the communication passages 73 and 71, to the water source 8 via the communication passages 73, 74, and 81, and to the air supply source 9 via the communication passages 73, 74, and 91. An on-off valve 72 is disposed in the communication passage 71, an on-off valve 82 is disposed in the communication passage 81, and an on-off valve 92 is disposed in the communication passage 91. By closing the on-off valves 82 and 92, opening the on-off valve 72, and operating the suction source 7, negative pressure can be transmitted through the frame 32 and generated on the holding surface 31 a of the porous plate 31. Furthermore, by closing the on-off valves 72 and 92, opening the on-off valve 82, and operating the water source 8, cleaning water can be supplied through the frame 32 and sprayed onto the holding surface 31 a of the porous plate 31. Furthermore, by closing the on-off valves 72 and 82, opening the on-off valve 92, and operating the air supply source 9, positive pressure can be transmitted via the frame 32 and generated on the holding surface 31a of the porous plate 31. Furthermore, by closing the on-off valve 72, opening the on-off valves 82 and 92, and operating the water source 8 and the air supply source 9, a mixed fluid of air and water can be sprayed onto the holding surface 31a of the porous plate 31.

[0019] The grinding means 4 includes at least a rotating shaft 41, a grinding wheel 42 disposed at the lower end of the rotating shaft 41, a plurality of grinding stones 43 disposed in an annular shape on the lower surface of the grinding wheel 42, an electric motor 44 for rotating the rotating shaft 41, a support part 45 for supporting the grinding means 4, and a Z-axis movable base 46 supported on the vertical wall part 2a of the device housing 2 so as to be movable up and down in the Z-axis direction together with the support part 45. The lifting means 5 converts the rotational motion of the pulse motor 51 into linear motion via a ball screw 52 rotated by the pulse motor 51 and transmits the linear motion to the Z-axis movable base 46, thereby enabling the grinding means 4 to move to any position in the Z-axis direction (up and down). The grinding water supply means 6 includes a grinding water supply source 61, a communication passage 62, and an on-off valve 63 for opening and closing the communication passage 62. The communication passage 62 is connected to the upper end 41a of the rotating shaft 41 of the grinding means 4. Grinding water W supplied from the grinding water supply source 61 is supplied through the inside of the rotary shaft 41 to the wafer 10 held on the chuck table 3 and to the grinding wheel 43 that grinds the wafer 10. The grinding device 1 is equipped with a control means (not shown), and the above-mentioned operating parts are controlled by control signals issued from the control means.

[0020] The grinding device 1 and the chuck table 3 of this embodiment have the configuration generally as described above, and their functions and actions will be described below.

[0021] When grinding the back surface 10b of the wafer 10 using the grinding apparatus 1 described above, the chuck table 3 is moved to the carry-in / out position as shown in Fig. 2, and the wafer 10 is placed on the holding surface 31a of the chuck table 3 with the back surface 10b side facing upward and the protective tape T side facing downward. Next, the on-off valve 72 described with reference to Fig. 4 is opened and the suction source 7 is operated to generate negative pressure on the holding surface 31a of the porous plate 31 to hold the wafer 10 by suction.

[0022] Next, the X-axis moving means is operated to position the chuck table 3 at a grinding position directly below the grinding means 4. Then, as shown in FIG. 5 , the chuck table 3 is rotated in the direction indicated by arrow R1 at a predetermined rotational speed (e.g., 300 rpm) by operating a rotation drive means (not shown), and the rotation shaft 41 of the grinding means 4 is rotated in the direction indicated by arrow R2 at a predetermined rotational speed (e.g., 3000 rpm). Next, the lifting means 5 is operated to lower the grinding means 4 in the direction indicated by arrow R3, bringing the grinding wheel 43 into contact with the back surface 10b of the wafer 10. The grinding water supply means 6 is operated to supply grinding water W to the grinding wheel 43 and the back surface 10b of the wafer 10 via the rotation shaft 41. In this manner, the wafer 10 is ground and thinned to a predetermined thickness while the grinding means 4 is fed at a predetermined speed (e.g., 1 μm / sec). When carrying out this grinding process, a thickness measuring means (not shown) can be operated to measure the thickness of the wafer 10 while carrying out the grinding process.

[0023] As described above, when grinding is performed using the grinding apparatus 1 of this embodiment, the frame 32 of the chuck table 3 has multiple grooves 33 formed in it, extending from the holding surface 31a to the side surface, so that the grinding water W, which is supplied to the grinding wheel 43 and the wafer 10 and contains contaminants, smoothly flows down the outer periphery of the chuck table 3, i.e., from the upper surface of the frame 32, due to the capillary action of the grooves 33 and the surface tension of the grinding water W flowing down the side surface of the frame 32, and is prevented from accumulating on the outer periphery of the chuck table 3. This eliminates the problem of a suction pad (not shown) sucking in contaminants and becoming contaminated when the operation of the suction source 7 is stopped and the wafer 10 is carried out of the chuck table 3 after grinding.

[0024] After the above-mentioned grinding process is completed, the above-mentioned on-off valves 72 and 92 are closed, on-off valve 82 is opened, and the water source 8 is operated to spray cleaning water onto the holding surface 31a of the porous plate 31 to clean the porous plate 31; alternatively, on-off valve 72 is closed, on-off valves 82 and 92 are opened, and the water source 8 and air supply source 9 are operated to spray a mixed fluid of air and water onto the holding surface 31a of the porous plate 31 to clean it, and then on-off valves 72 and 82 are closed, on-off valve 92 is opened, and the air supply source 9 is operated to supply drying air to the porous plate 31 to dry it. In this case, since the above-mentioned groove 33 is formed in the frame body 32 of the chuck table 3, the cleaning water sprayed from inside the frame body 32 toward the holding surface 31a of the porous plate 31 cleans the porous plate 31 and flows smoothly down to the outside of the frame body 32, preventing it from accumulating on the frame body 32.This eliminates the problem of clogging caused by the porous plate 31 of the chuck table 3 sucking in water containing contaminants that has accumulated on the frame body 32 when it suction-holds the next wafer 10. [Explanation of symbols]

[0025] 1: Grinding device 2: Device housing 3: Chuck table 31: Porous plate 31a: Holding surface 32:Frame body 33: Groove 4: Grinding means 41: Rotation axis 41a top end 42: Grinding wheel 43: Grinding wheel 44: Electric motor 45: Support part 46:Z-axis moving base 5: Lifting means 51: Pulse motor 52: Ball screw 6: Grinding water supply means 61: Grinding water supply source 62: Communication path 63: On-off valve 7: Suction source 71, 73, 74: Communication path 72: On-off valve 8: Water source 81:Communication path 82: On-off valve 9: Air supply source 91:Communication path 92: On-off valve 10: Wafer 12: Device 14: Planned division line T: Protective tape W: Grinding water

Claims

1. A chuck table for holding a wafer, A porous plate having a holding surface that suction-holds a wafer, and a frame that supports the outer periphery and bottom surface of the porous plate and transmits negative pressure and positive pressure to the holding surface, The frame has a plurality of grooves formed therein, the grooves extending from the holding surface to the side surface, The upper surface of the holding surface and the upper surface of the frame are formed flush with each other.

2. A chuck table for holding a wafer, A porous plate having a holding surface that suction-holds a wafer, and a frame that supports the outer periphery and bottom surface of the porous plate and transmits negative pressure and positive pressure to the holding surface, The frame has a plurality of grooves formed therein, the grooves extending from the holding surface to the side surface, The groove is a groove for allowing grinding water that has flowed over the wafer held on the holding surface to flow down the groove.

3. A chuck table for holding a wafer, comprising: A porous plate having a holding surface that suction-holds a wafer, and a frame that supports the outer periphery and bottom surface of the porous plate and transmits negative pressure and positive pressure to the holding surface, The frame has a plurality of grooves formed therein, the grooves extending from the holding surface to the side surface and reaching the lower end of the side surface.

4. A grinding device comprising: a chuck table for holding a wafer; a grinding means having a rotatable grinding wheel on which grinding stones for grinding the wafer held on the chuck table are arranged in a ring shape; and a grinding water supply means for supplying grinding water to the grinding stones and the wafer, 4. A grinding apparatus, wherein the chuck table is the chuck table according to any one of claims 1 to 3.

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