Wafer grinding device

Abstract

To provide a wafer grinding device capable of grinding a wafer in a state where a grindstone unit that grinds the wafer is accurately mounted.SOLUTION: A grinding device 1 includes a spindle 4 that is provided in a vertically movable manner and rotates about a rotation shaft CL, and a mounting section 6 that automatically magnetically attaches a grindstone unit 5 to the spindle 4, and grinds a wafer 10 by rotating the grindstone unit 5 mounted by the mounting section 6. A pipe 44 is inserted through the rotation shaft CL of the spindle 4, and air is made to pass through the pipe 44. A pressure sensor 92 detects the mounting state of the grindstone unit 5.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a grinding apparatus for grinding wafers, and more particularly to a wafer grinding apparatus that is capable of detecting whether or not a grinding wheel is attached to a spindle. [Background technology]

[0002] Conventionally, semiconductor wafers that have been thinly sliced ​​using a wire saw are ground even thinner using a grinding device, but when replacing the grinding wheel unit used for this grinding, a method has been proposed in which the grinding wheel unit is magnetically attached to enable replacement (Patent Document 1).

[0003] The method for replacing a grinding wheel unit in Patent Document 1 (see paragraph 62) involves providing an electromagnet below the spindle and providing a grinding wheel unit with a grinding wheel flange made of iron, and switching the electromagnet between a magnetized and demagnetized state to enable replacement with a new grinding wheel unit. By adopting such a configuration, it is no longer necessary to insert a tool from below to remove screws during replacement, as was previously the case, making the replacement work easier. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-148361 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the grinding wheel unit is made replaceable by a method other than manual replacement, the following problems arise.

[0006] That is, conventionally, grinding wheel units are attached manually, so the attachment status can be checked by touching with one's hand, but if the grinding wheel unit is attached automatically using an electromagnet or the like, the attachment status cannot be checked.

[0007] Furthermore, even if the grinding wheel unit is attached manually, there is a possibility that the grinding wheel unit may become loose during the grinding process, and in such a case, there is a risk that the grinding wheel unit may fall off, leading to damage to the grinding device.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a wafer grinding apparatus that can grind wafers with a grindstone unit that is accurately attached. [Means for solving the problem]

[0009] In other words, in order to solve the above-mentioned problems, the present invention provides a grinding device that includes a spindle that can be raised and lowered freely and rotates around a rotation axis, a mounting part for mounting a grinding wheel unit to the spindle, and a detection means for detecting the mounting state of the grinding wheel unit to the spindle by rotating the grinding wheel unit mounted by the mounting part.

[0010] With this configuration, if the grinding wheel unit is not installed correctly, this can be detected, thereby reducing the risk of the grinding wheel unit coming off during grinding operations and damaging the grinding device.

[0011] In addition, in such an invention, the rotation axis of the spindle is provided with a conductive passage that passes through to the mounting surface side of the grinding wheel unit, and the detection means detects the mounting state of the grinding wheel unit by the pressure of air passing through the conductive passage.

[0012] This configuration makes it easier to set the threshold value compared to using a proximity sensor, and eliminates the effects of magnetic force. It also has the advantage of eliminating the need to handle cables during rotation.

[0013] Furthermore, the rotation axis of the spindle is provided with a conductive passage that penetrates to the mounting surface side of the grinding wheel unit, and air and water are passed through the conductive passage, so that the mounting state of the grinding wheel unit can be detected by a detection means based on the pressure of the air passing through the conductive passage, and the wafer can be ground using water passing through the conductive passage.

[0014] With this configuration, the air for detecting the air pressure and the water for grinding can be passed through a common conduction path, which simplifies the structure.

[0015] The rotation axis of the spindle is provided with a conductive passage that penetrates to the grinding wheel unit side, and the detection means passes air through a tube that passes through the conductive passage, and detects the installation state of the grinding wheel unit by the pressure of the air.A gap area that allows water to pass through is formed in the gap between the tube and the conductive passage, and the water is discharged from the side of the spindle.

[0016] With this configuration, the cooling effect of the spindle can be improved by passing water through the spindle. [Effects of the Invention]

[0017] According to the present invention, in a grinding device that includes a spindle that can be raised and lowered and rotates around a rotation axis, a mounting portion for mounting a grinding wheel unit to the spindle, and that rotates the grinding wheel unit mounted by the mounting portion to grind wafers, a detection means is provided for detecting the mounting state of the grinding wheel unit to the spindle.This makes it possible to detect if the grinding wheel unit is not mounted correctly, and reduces the risk of the grinding wheel unit coming off during grinding operations and damaging the grinding device. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic plan view of a wafer grinding apparatus according to an embodiment of the present invention; [Figure 2] A diagram showing the state in which the grinding wheel unit is attached to the attachment part in the same configuration. [Figure 3] FIG. 10 shows an index table and a mounting member in the same embodiment. [Figure 4] FIG. 10 is a diagram showing a state in which a grinding wheel unit is replaced in the same embodiment. [Figure 5] FIG. 10 is a diagram showing a state in which a grinding wheel unit is replaced in the same embodiment. [Figure 6] Schematic diagram showing a cross section of the spindle in the same configuration [Figure 7] FIG. 10 is a diagram showing a circular member having a water discharge portion in the same embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] As shown in FIG. 1, the grinding apparatus 1 in this embodiment includes a plurality of chuck tables 2 that rotate while holding wafers 10 (shown in shaded areas), an index table 3 that moves the chuck tables 2 between a rough grinding position A1, a finish grinding position A2, and the like, a grinding stone unit 5 that grinds the wafers 10 held on the chuck tables 2, a spindle 4 that raises and lowers the grinding stone unit 5 and rotates it, and a mounting unit 6 (see FIG. 2) that lowers the spindle 4 to magnetically attach the grinding stone unit 5 placed on the chuck table 2. Characteristically, the apparatus includes a detector 9 (see FIG. 6) that detects whether the grinding stone unit 5 is correctly attached to the spindle 4 when magnetically attaching the grinding stone unit 5 to the spindle 4. This allows the grinding operation to be stopped if the grinding stone unit 5 is not correctly attached. This embodiment will be described in detail below.

[0021] 1, the chuck table 2 of the grinding device 1 is configured to have a diameter slightly larger than that of the wafer 10, and is configured so that the wafer 10 is attracted to its upper surface by an air suction mechanism (not shown). With the wafer 10 attracted by air, it is rotated by a motor (not shown) provided below.

[0022] As shown in Fig. 3, the index table 3 has a plurality of openings 31 for accommodating the chuck table 2, and is configured so that the chuck table 2 (not shown in Fig. 3) accommodated in the openings 31 can be rotated by a motor and moved between a rough grinding position A1 (see Fig. 1), a finish grinding position A2, etc. An intermediate section 32 is provided between the openings 31 of the index table 3, and a radial slider 33 provided in this intermediate section 32 is attached to a mounting member 7 for mounting the grinding wheel unit 5 thereon.

[0023] Meanwhile, a spindle 4 is provided near the index table 3. As shown in Figures 4 and 5, the spindle 4 raises and lowers a grinding stone unit 5 in the normal direction (Z-axis direction) of the wafer 10, and rotates the grinding stone unit 5 by pressing it against the surface of the wafer 10. A grinding stone unit 5 for rough grinding is attached to one side of the spindle 4, and a grinding stone unit 5 for finish grinding is attached to the other side.

[0024] As shown in Fig. 2, the grinding wheel unit 5 attached to the spindle 4 has a plurality of grinding wheels 53 attached in the circumferential direction below a grinding wheel flange 51 made of a magnetic metal, and is attached in alignment with the rotation axis CL of the spindle 4. When attaching the grinding wheel unit 5 to be aligned with the rotation axis CL of the spindle 4, a conical protrusion 55 protruding from the center of the grinding wheel flange 51 is inserted into a circular opening 41 provided below the rotation axis CL of the spindle 4, as shown in Fig. 6, thereby enabling alignment.

[0025] The mounting unit 6, located below the spindle 4, allows the grinding wheel unit 5 to be automatically attached to and detached from the spindle 4. The mounting unit 6 can be switched between an attached state and a detached state using a switching unit 60 (see FIG. 2). While various structures can be used for the mounting unit 6, a structure that magnetizes the grinding wheel unit 5 is used here. Specifically, the mounting unit 6 has a permanent magnet inside. By inserting a pin 62 of the switching unit 60 into a switching hole 61 provided on the side of the mounting unit 6 and rotating it 180 degrees, the mounting unit 6 can be switched between a magnetized state and a demagnetized state using the permanent magnet. The pin 62 for this switching is slidable from the side when the spindle 4 is lowered. The pin 62 is advanced by a cylinder 63 and inserted into the switching hole 61. In this state, the pin 62 is rotated 180 degrees using a motor 64, thereby switching between the magnetized state (mounted state) and the demagnetized state (detached state). In this way, by allowing the grinding wheel unit 5 to be removed only when the grinding wheel unit 5 is lowered, impact due to dropping is prevented even when the grinding wheel unit 5 is dropped. Note that if the grinding wheel unit 5 is merely magnetically attached to the underside of the spindle 4, the grinding wheel unit 5 may slide against the underside of the spindle 4 due to frictional force during rotation. Therefore, to prevent this rubbing, a columnar member 42 is provided hanging down from the spindle 4, and the lower end of this columnar member 42 is fitted into a hole 54 (see FIG. 1 ) in the upper surface of the grinding wheel flange 51 to prevent sliding. Note that, although the columnar member 42 is provided here to fit into the hole 54, sliding may be prevented without providing the columnar member 42.

[0026] On the other hand, on the index table 3, a mounting member 7 for mounting the grindstone unit 5 thereon is provided.

[0027] The mounting member 7 is configured to mount the grindstone unit 5. In this embodiment, the mounting member 7 has a thickness that prevents the grindstone 53 from contacting the index table 3 or the chuck table 2 when the grindstone unit 5 is mounted thereon, and a size that prevents the grindstone flange 51 from interfering with the chuck table 2. The mounting member 7 is also formed with a rectangular recess 72 (see FIG. 3), into which a rectangular fitting member 52 (see FIGS. 2 and 3) of the same shape provided on the underside of the grindstone flange 51 can be fitted and fixed. The mounting member 7 is slidable along a slider 33 that extends radially of the index table 3 and is fixed in a predetermined position with a screw 71. When the mounting member 7 is attached to the index table 3, the mounting member 7 is positioned within the slider 33 and fixed with the screw 71 so that the rotation axis CL of the grindstone flange 51 fixed in the rectangular recess 72 coincides with the rotation axis CL of the spindle 4 when the index table 3 is rotated.

[0028] The control unit 8 (FIG. 2) controls the cylinder 63, motor 64, etc. to perform this series of operations, and by operating a switch, moves the mounting member 7 to a position below the spindle 4, and controls the grinding wheel unit 5 to be lowered to the vicinity of the mounting member 7, and then drives the switching unit 60 to place the grinding wheel unit 5 on the mounting member 7. When a new grinding wheel unit 5 is to be attached, the new grinding wheel unit 5 is placed on the mounting member 7 at the grinding wheel replacement position, and with the grinding wheel unit 5 moved to a position below the spindle 4 (the state in FIG. 4(a)), the spindle 4 is lowered (the state in FIG. 4(b)), and the switching unit 60 is driven to magnetize the grinding wheel unit 5. In addition, when stopping the grinding wheel unit 5 placed on the mounting member 7 at a position below the rotation axis CL of the spindle 4, a method can be used in which a mark or the like is attached to the index table 3 or the mounting member 7, and this mark is read by an optical sensor to control the stopping position so that the rotation axis CL of the spindle 4 and the rotation axis of the grinding wheel unit 5 are aligned.

[0029] With this configuration, in this embodiment, a detection unit 9 is provided that can detect whether the grindstone unit 5 is correctly attached to the spindle 4 or not.

[0030] This detection unit 9 can use a proximity sensor, optical sensor, vibration sensor, etc. to detect whether the grinding wheel unit 5 is correctly attached to the spindle 4. In this case, as shown in Figure 6, a conductive passage 43 for passing air is provided on the rotation axis CL of the spindle 4, and air is constantly passed through this passage. A pressure sensor 92 is provided on the side of the air compressor 91 that sends out this air, and by detecting changes in pressure using this pressure sensor 92, the attachment status of the grinding wheel unit 5 can be detected.

[0031] Specifically, a small-diameter pipe 44 extending in the vertical direction is provided in a hollow conduction passage 43 provided along the rotation axis CL of the spindle 4, and air can be sent into the interior from an external air compressor 91. The lower end portion of this pipe 44 is provided up to the vicinity of the circular opening 41, and when the conical protrusion 55 of the grinding wheel unit 5 is accurately fitted into the circular opening 41, the circular opening 41 blocks air, but when the protrusion 55 is not properly fitted into the circular opening 41, air is discharged from the circular opening 41.

[0032] Meanwhile, grinding water passes through an annular gap 45 on the outside of the pipe 44 in the conduit 43 of the spindle 4, and is discharged from there to the side of the spindle 4. When discharging water from the side of the spindle 4 in this way, a circular member 46 (see Figures 6 and 7) is provided below the spindle 4, and the water is discharged to the side from a plurality of grooves 47 (see Figure 7) provided in the upper surface of the circular member 46. The discharge portion of the grooves 47 constitutes the discharge section of the present invention.

[0033] Next, a method for replacing the grinding wheel unit 5 in the grinding device 1 configured as above and a method for detecting the mounting state of the grinding wheel unit 5 will be described. In the explanation, it is assumed that the old grinding wheel unit 5 is already mounted on the mounting portion 6 of the spindle 4, and the case where the old grinding wheel unit 5 is removed and replaced with a new grinding wheel unit 5 will be described.

[0034] First, when removing the old grinding wheel unit 5, set the switch to "removal mode 81" (Figure 2) and rotate the mounting member 7 on the index table 3 until it is directly below the rotation axis CL of the spindle 4 (the state shown in Figure 4(a)).

[0035] Then, in this state, the spindle 4 is lowered and the grindstone unit 5 is stopped at a position near the mounting member 7 (for example, at a position several millimeters away) (the state of FIG. 4(b)).

[0036] Next, the switching hole 61 of the mounting portion 6 provided on the spindle 4 is oriented in the sliding direction of the pin 62, and in this state, the pin 62 is advanced via the cylinder 63. Then, the pin 62 is inserted into the switching hole 61, and the pin 62 is rotated 180 degrees.

[0037] Then, the mounting portion 6 switches from a magnetized state to a demagnetized state, and the grinding wheel unit 5 falls onto the mounting member 7 (the state shown in FIG. 5(c)). When the grinding wheel flange 51 falls in this manner, the fitting member 52 of the grinding wheel flange 51 fits into the pin 62 of the mounting member 7, and the grinding wheel flange 51 is fixed in place.

[0038] When dropping the grindstone unit 5, air may be discharged from the pipe 44 in the guide passage 43 of the spindle 4, and the air pressure may also be used to make it easier to drop the grindstone unit 5.

[0039] Next, with the grindstone flange 51 removed in this manner, the spindle 4 is raised (the state shown in FIG. 5(d)), and the index table 3 is rotated to move it to the grindstone replacement position A3 (see FIG. 1) of the grindstone unit 5. Then, the old grindstone unit 5 is picked up with both hands and collected.

[0040] Next, when attaching a new grinding wheel unit 5, the reverse operation is performed. That is, the new grinding wheel unit 5 is carried to the grinding wheel replacement position A3 and placed on the mounting member 7. At this time, the fitting member 52 of the grinding wheel unit 5 is fitted onto the pin 62 of the mounting member 7.

[0041] Then, the switch is changed to “attachment mode 82 ”, the index table 3 is rotated, and the grindstone unit 5 placed on the placement member 7 is moved to directly below the rotation axis CL of the spindle 4 .

[0042] Then, the spindle 4 is lowered, and at this position, the pin 62 of the switching portion 60 is advanced and inserted into the switching hole 61 of the mounting portion 6, and then rotated 180 degrees in the opposite direction.

[0043] As a result, the grinding wheel unit 5 is magnetically attached to the mounting portion 6 of the spindle 4 and is lifted from the mounting member 7. At this time, the columnar member 42 hanging down from the spindle 4 is fitted into the hole 54 provided on the upper surface of the grinding wheel flange 51, and the grinding wheel unit 5 is fixed so as not to be able to slide in the rotational direction.

[0044] When attaching the grinding wheel unit 5 in this manner, if air is being discharged from the tube 44 of the conduction passage 43 of the spindle 4, it may be difficult to magnetize the grinding wheel unit 5. In such a case, it may be possible to block air from the air compressor 91.

[0045] Then, with the grindstone unit 5 magnetically attached in this manner, the pin 62 of the switching portion 60 is retracted and the spindle 4 is raised.

[0046] The wafer 10 is then ground using the new grinding wheel unit 5 thus replaced. During this grinding operation, water is supplied to the wafer 10 side by passing it through the gap 45 on the outside of the tube 44 of the spindle 4, and water is also supplied to the wafer 10 side through the groove 47 of the circular member 46. At the same time, air is passed through the tube 44 provided in the conduit 43 of the spindle 4, and the air pressure is constantly measured by the pressure sensor 92. If the air pressure is above a certain value, it is determined that the grinding wheel unit 5 is properly attached, and if the air pressure is below the certain value, it is determined that the grinding wheel unit 5 is not properly attached and air is leaking, and the grinding operation is stopped.

[0047] As described above, according to the embodiment, the grinding device 1 includes a spindle 4 that can be raised and lowered and rotates around a rotation axis CL, a mounting portion 6 for mounting a grinding wheel unit 5 to the spindle 4, and a pressure sensor 92 that detects the mounting state of the grinding wheel unit 5 relative to the spindle 4 by rotating the grinding wheel unit 5 mounted by the mounting portion 6.This makes it possible to detect if the grinding wheel unit 5 is not mounted correctly, thereby reducing the risk of the grinding wheel unit 5 coming off during grinding operation and damaging the grinding device 1.

[0048] The present invention is not limited to the above-described embodiment, but can be implemented in various forms.

[0049] For example, in the above embodiment, the case where the grinding wheel unit 5 is attached by magnetic adhesion is described, but the present invention can also be applied to a case where the grinding wheel unit 5 is attached manually using bolts or the like.Furthermore, when the grinding wheel unit 5 is attached by a method other than manual attachment, a method of attaching the grinding wheel unit 5 by a method other than magnetic adhesion can also be used.

[0050] In the above embodiment, air is sent into the tube 44 of the convex passage 43 of the spindle 4 to detect air leakage from the conical protrusion 55 and the circular opening 41 of the grinding wheel unit 5, thereby enabling the installation status of the grinding wheel unit 5 to be detected. However, it is preferable to allow some pressure change so that the installation status can be determined. Also, while air is sent here, conversely, the installation status may be detected by sucking in air during installation rather than by sending in air. Note that if this suction is performed, the decompressed air can help ensure that the grinding wheel unit 5 is installed properly.

[0051] Furthermore, in the above embodiment, the mounting state of the spindle 4 can be detected using the pressure sensor 92, but the mounting state may also be detected using various methods such as an optical sensor, a vibration sensor, or a proximity sensor. [Explanation of symbols]

[0052] 1. Grinding equipment 2. Chuck table 3. Index table 4. Spindle 46 Circular member 47...Groove (discharge part) 5. Grinding wheel unit 55...Protrusion 6. Mounting part 7. Mounting member 8. Control section 9. Detection means 91···Air compressor 92 Pressure Sensor

Claims

1. a spindle that is provided so as to be able to freely rise and fall and that rotates around a rotation axis; a mounting portion for mounting a grinding wheel unit on the spindle; In the grinding apparatus, the grinding stone unit mounted by the mounting portion is rotated to grind the wafer, A wafer grinding apparatus characterized in that it is provided with a detection means for detecting the attachment state of the grinding stone unit to the spindle.

2. The spindle has a guide passage penetrating the rotary shaft on the side of the mounting surface of the grinding wheel unit, 2. The wafer grinding device according to claim 1, wherein said detecting means detects the mounting state of the grinding stone unit by the pressure of air passing through said conducting passage.

3. The spindle has a guide passage penetrating the rotary shaft on the side of the mounting surface of the grinding wheel unit, The conductive path allows air and water to pass through, the detection means detects the attachment state of the grinding wheel unit based on the pressure of air passing through the conduction passage, 2. The wafer grinding apparatus according to claim 1, wherein the wafer is ground by water passing through said conducting passage.

4. The spindle has a guide passage penetrating the rotary shaft on the side of the mounting surface of the grinding wheel unit, the detection means passes air through a tube passing through the conduction passage and detects the attachment state of the grinding wheel unit based on the pressure of the air, 2. The wafer grinding device according to claim 1, further comprising a gap between said pipe and said conducting passage for allowing water to pass therethrough, and a discharge section for discharging said water from a side of said spindle.

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