Grinding apparatus

Abstract

To shorten downtime accompanying replacement of a grinding wheel, in a grinding device having a plurality of grinding mechanisms.SOLUTION: The grinding apparatus 1 includes the turntable 20 having at least three chuck tables, the grinding mechanism 50 (grinding mechanism 80) on which the grinding wheel 53 (grinding wheel 83) is mounted, the feeding mechanism 40 (feeding mechanism 70) that grind-feeds the grinding mechanism 50 (grinding mechanism 80), the first distance recognition section (second distance recognition section) that recognizes the distance between the holding surface and the upper surfaces of the grindstones 55 (grindstones 85), the carrying-in mechanism 17 and the carrying-out mechanism 18 that carry the wafer onto and out of the chuck tables, and the control section 90. When the distance recognized during grinding reaches a limit value, the control unit 90 brings the grinding mechanism into a state in which the grinding wheel can be replaced, carries out the wafer from one chuck table by the carrying-out mechanism, and moves the chuck table that does not hold the wafer to a position directly under the grinding mechanism that has replaced the grinding wheel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A known grinding device for grinding wafers with grinding wheels is equipped with multiple grinding mechanisms. In such a grinding device, the timing at which the grinding wheels of the multiple grinding mechanisms wear out and reach their service limits generally does not coincide. Patent Document 1 proposes a technology for synchronizing the replacement of multiple grinding wheels by adjusting the timing at which the wheels reach their service limits in order to streamline warm-up operations after replacement and reduce downtime. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-158871 Summary of the Invention [Problem to be solved by the invention]

[0004] However, synchronizing the replacement times of multiple grinding wheels by, for example, intentionally increasing the wear rate of the grinding wheels in some grinding mechanisms beyond the standard is uneconomical, and a different approach is needed.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a technique for reducing downtime associated with replacing grinding wheels in a grinding device equipped with multiple grinding mechanisms. [Means for solving the problem]

[0006] A grinding device according to one aspect of the present invention includes a holding mechanism that holds and rotates a wafer by a holding surface, a turntable that has at least three of the holding mechanisms arranged thereon and rotates about its axis, a first grinding mechanism equipped with a first grinding wheel having a first annular grinding stone arranged thereon for grinding the wafer, a second grinding mechanism equipped with a second grinding wheel having a second annular grinding stone arranged thereon for grinding the wafer, a first grinding feed mechanism that feeds the first grinding mechanism in a direction perpendicular to the holding surface for grinding, a second grinding feed mechanism that feeds the second grinding mechanism in a direction perpendicular to the holding surface for grinding, a first distance recognition unit that recognizes the distance between the holding surface and an upper surface of the first grinding stone, a second distance recognition unit that recognizes the distance between the holding surface and an upper surface of the second grinding stone, and a transfer mechanism that transfers the wafer into the holding mechanism. The grinding device is provided with at least an insertion mechanism and a carry-out mechanism that carries out the wafer held by the holding mechanism from the holding mechanism, and a control unit that, when the distance recognized by the first distance recognition unit or the second distance recognition unit reaches a preset grinding wheel limit value while the first grinding mechanism and the second grinding mechanism are performing grinding processing, puts the grinding mechanism, which is the first grinding mechanism or the second grinding mechanism whose distance has reached the grinding wheel limit value, into a state where the grinding wheel attached to the grinding mechanism can be replaced, and, when all of the holding mechanisms arranged on the turntable are holding wafers, carries out the wafer from one of the holding mechanisms arranged on the turntable by the carry-out mechanism and moves the holding mechanism that is not holding a wafer to directly below the grinding mechanism. [Effects of the Invention]

[0007] According to the present invention, in a grinding device equipped with a plurality of grinding mechanisms, downtime due to replacement of grinding wheels can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a grinding device according to a first embodiment. [Figure 2] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which wear of a grinding stone is detected. [Figure 3]10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which the grinding mechanism has been retracted. [Figure 4] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which the grinding wheel has been replaced. [Figure 5] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which a turntable is rotated. [Figure 6] FIG. 10 is a perspective view of a grinding device according to a second embodiment. [Figure 7] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which wear of a grinding stone is detected. [Figure 8] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which the grinding mechanism has been retracted. [Figure 9] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which the grinding wheel has been replaced. [Figure 10] 10 is a diagram for explaining the replacement support process for supporting the replacement of the grinding wheel, and shows the state in which the dressing grindstone is placed on the chuck table. FIG. [Figure 11] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which a turntable is rotated. [Figure 12] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which dressing is being performed. [Figure 13] 10A and 10B are diagrams for explaining a replacement support process for supporting replacement of a grinding wheel, and show a state in which a turntable is rotated. [Figure 14] 10 is a diagram illustrating a replacement support process for supporting replacement of a grinding wheel, showing the state in which the dressing wheel has been removed from the chuck table. FIG. [Figure 15] FIG. 10 is a perspective view of a grinding device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) The grinding device and the method for replacing the grinding wheel will be described below with reference to the accompanying drawings. Fig. 1 is a perspective view of a grinding device 1 according to this embodiment. The grinding device 1 shown in Fig. 1 is a fully automatic processing device, and is configured to automatically perform a series of operations for a wafer W, which is a workpiece, including a loading process, a rough grinding process, a finish grinding process, a cleaning process, and a loading process.

[0010] The wafer W is formed in a substantially circular disk shape and is carried into the grinding apparatus 1 with a protective tape T attached to its underside. The wafer W may be a semiconductor substrate such as silicon or gallium arsenide, or an inorganic material substrate such as ceramic, glass, or sapphire, or may even be a package substrate for a semiconductor product. The wafer W may also be carried into the grinding apparatus 1 without a protective tape T attached to its underside.

[0011] The X-axis, Y-axis, and Z-axis directions of the grinding apparatus 1 are perpendicular to one another. The X-axis and Y-axis directions are approximately horizontal, and the Z-axis direction is an up-down direction (approximately vertical). Of the two arrows indicating the X-axis direction, the side marked with the letter X is the front, and the side without the letter X is the rear. Of the two arrows indicating the Y-axis direction, the side marked with the letter Y is the left, and the side without the letter Y is the right. Of the two arrows indicating the Z-axis direction, the side marked with the letter Z is the up, and the side without the letter Z is the down.

[0012] A pair of cassettes (cassette 11, cassette 19) capable of accommodating a plurality of wafers W are placed on the front side of a base 10 of the grinding apparatus 1. The cassette 11 is a cassette that accommodates wafers W before grinding, and the cassette 19 is a cassette that accommodates wafers W before grinding. Behind the pair of cassettes, a robot hand 12 is provided that puts and takes wafers W into and out of the cassette 11 and the cassette 19. The robot hand 12 is configured by providing a hand portion at the tip of a robot arm made up of a multi-joint link.

[0013] A positioning mechanism 13 that positions the wafer W before grinding is provided diagonally to the rear right of the robot hand 12. The positioning mechanism 13 is configured by arranging a plurality of positioning pins 15 that are movable forward and backward in the radial direction of the positioning table 14 around the periphery of the positioning table 14. In the positioning mechanism 13, the plurality of positioning pins 15 abut against the outer periphery of the wafer W placed on the positioning table 14, thereby positioning the wafer W so that its center coincides with the center of the positioning table 14.

[0014] A cleaning mechanism 16 for cleaning the ground wafer W is provided diagonally to the rear left of the robot hand 12. The cleaning mechanism 16 is equipped with various nozzles (not shown) for spraying cleaning water and dry air toward a spinner table (not shown). In the cleaning mechanism 16, the spinner table holding the wafer W is lowered into the base 10, cleaning water is sprayed onto the wafer W within the base 10 for spinner cleaning, and then dry air is blown onto the wafer W to dry it.

[0015] The robot hand 12 transports the wafer W before grinding from the cassette 11 to the positioning mechanism 13, and transports the wafer W after grinding from the cleaning mechanism 16 to the cassette 11.

[0016] Between the positioning mechanism 13 and the cleaning mechanism 16, a carry-in mechanism 17 and a carry-out mechanism 18 are provided, and further behind them, a turntable 20 equipped with three chuck tables (chuck table 21, chuck table 22, chuck table 23) is provided.

[0017] The loading mechanism 17 is a loading mechanism that loads the wafer W before grinding onto the chuck table, and is configured by providing a holding pad at the tip of a support arm that can rotate around an axis in the Z-axis direction on the base 10. In the loading mechanism 17, the holding pad holds the wafer W by suction, thereby lifting it from the positioning table 14. Furthermore, the holding pad is rotated by the support arm, thereby loading the wafer W onto the chuck table.

[0018] The carry-out mechanism 18 is a mechanism that carries out the ground wafer W held on the chuck table from the chuck table, and is configured by providing a holding pad at the tip of a support arm that can rotate around an axis in the Z-axis direction on the base 10. In the carry-out mechanism 18, the holding pad lifts the wafer W from the chuck table by suction-holding the wafer W. Furthermore, the holding pad is rotated by the support arm, so that the wafer W is carried out from the chuck table to the cleaning mechanism 16.

[0019] Three chuck tables (chuck table 21, chuck table 22, and chuck table 23) are arranged at equal intervals around the circumferential direction of the turntable 20. Furthermore, the turntable 20 is configured to rotate (spin) around a rotation axis in the Z-axis direction. The turntable 20 is rotationally driven by a table driving mechanism (not shown).

[0020] Each chuck table has a porous member at its top that is connected to a suction source. The upper surface of the porous member serves as a holding surface that holds the wafer W by suction. Each chuck table is supported so as to be rotatable about a central axis that passes through the center of the holding surface. In other words, each chuck table is a holding mechanism that holds and rotates the wafer W by its holding surface.

[0021] The three chuck tables are positioned, in this order, as the turntable 20 rotates intermittently at 120-degree intervals: a load / unload position where the wafer W is loaded and unloaded by the load mechanism 17 and the unload mechanism 18; a first grinding position where the grinding wheel 55 of the grinding mechanism 50 grinds the wafer W; and a second grinding position where the grinding wheel 85 of the grinding mechanism 80 grinds the wafer W. At the first grinding position, the grinding wheel 55 roughly grinds the wafer W on the chuck table (chuck table 22) to a predetermined thickness. At the second grinding position, the grinding wheel 85 finish-grinds the wafer W on the chuck table (chuck table 23) to a finish thickness.

[0022] The grinding mechanism 50 is a first grinding mechanism in which a grinding wheel 53 is attached to a disk-shaped mount 52 at the lower end of a spindle 51 extending in the Z-axis direction. The spindle 51 is not particularly limited, but may be, for example, an air spindle, and is supported rotatably about an axis in the Z-axis direction via high-pressure air.

[0023] The grinding wheel 53 is a first grinding wheel that includes an annular wheel base 54 and a grinding stone 55 that grinds the wafer W arranged in an annular shape on the wheel base 54. When the grinding stone 55 of the grinding wheel 53 wears out, it is removed from the mount 52 and replaced.

[0024] The grinding mechanism 80 is a second grinding mechanism in which a grinding wheel 83 is attached to a disk-shaped mount 82 at the lower end of a spindle 81 extending in the Z-axis direction. The spindle 81 is not particularly limited, but may be, for example, an air spindle, and is supported rotatably about an axis in the Z-axis direction via high-pressure air.

[0025] The grinding wheel 83 is a second grinding wheel that includes an annular wheel base 84 and a grinding stone 85 that grinds the wafer W arranged annularly on the wheel base 84. When the grinding stone 85 of the grinding wheel 83 wears out, it is removed from the mount 82 and replaced.

[0026] The grinding wheel 55 and the grinding wheel 85 are made of diamond grinding wheels in which diamond abrasive grains are bound with a binder such as a metal bond or a resin bond. The grinding wheel 85 is made of abrasive grains with a finer grain size than the grinding wheel 55.

[0027] Behind the first grinding position and the second grinding position on the turntable 20, a column 30 that supports the grinding mechanism 50 and a column 60 that supports the grinding mechanism 80 are provided in an upright position.

[0028] The front surface of the column 30 is provided with a feed mechanism 40 that feeds the grinding mechanism 50 for grinding in a direction perpendicular to the holding surface of the chuck table 22. The feed mechanism 40 is a first grinding feed mechanism, and is provided with a ball screw 41 extending in a direction parallel to the Z-axis direction, a pair of guide rails 42 extending in a direction parallel to the Z-axis direction, a motor 43 connected to one end of the ball screw 41, and a table 44 slidably installed on the guide rails 42, on the front surface of the column 30. A nut portion (not shown) that is threaded onto the ball screw 41 is formed on the back surface of the table 44. In the feed mechanism 40, the table 44 moves in the Z-axis direction due to rotation of the motor 43, and accordingly, the grinding mechanism 50 fixed to the table 44 moves in the Z-axis direction.

[0029] A feed mechanism 70 is provided on the front surface of the column 60, which feeds the grinding mechanism 80 for grinding in a direction perpendicular to the holding surface of the chuck table. The feed mechanism 70 is a second grinding feed mechanism, and is provided on the front surface of the column 60 with a ball screw 71 extending in a direction parallel to the Z-axis direction, a pair of guide rails 72 extending in a direction parallel to the Z-axis direction, a motor 73 connected to one end of the ball screw 71, and a table 74 slidably installed on the guide rails 72. A nut portion (not shown) threadedly engaged with the ball screw 71 is formed on the back surface of the table 74. In the feed mechanism 70, the table 74 moves in the Z-axis direction due to rotation of the motor 73, and accordingly, the grinding mechanism 80 fixed to the table 74 moves in the Z-axis direction.

[0030] The grinding apparatus 1 further includes a control unit 90. The control unit 90 includes, for example, a processor and a memory, and executes a program stored in the memory to control the operation of each unit of the grinding apparatus 1. For example, the processor executes the program, and the grinding apparatus 1 performs a series of processes, including a carry-in process, a rough grinding process, a finish grinding process, a cleaning process, and a carry-out process, in a fully automatic manner.

[0031] In the grinding apparatus 1, the control unit 90 is configured to perform a process for supporting the replacement of the grinding wheel and the subsequent work (hereinafter referred to as the replacement support process). Specifically, when the grinding wheel wears beyond a predetermined limit during the grinding process, the control unit 90 is configured to interrupt the above-described series of processes and make the grinding wheel replaceable, thereby prompting the user to replace the grinding wheel. Furthermore, once the user has replaced the grinding wheel, the control unit 90 is configured to prompt the user to perform work to return to the interrupted series of processes. This allows the user to replace the grinding wheel and perform the subsequent work with support from the grinding apparatus 1. Therefore, the replacement of the grinding wheel and the subsequent work are performed smoothly, allowing the grinding apparatus 1 to quickly return to the fully automatic series of processes.

[0032] 2 to 5 are diagrams illustrating the grinding wheel replacement support process in the grinding apparatus 1. Fig. 2 shows the state in which wear of the grinding stone is detected, Fig. 3 shows the state in which the grinding mechanism is retracted, Fig. 4 shows the state in which the grinding wheel has been replaced, and Fig. 5 shows the state in which the turntable has been rotated. Below, with reference to Figs. 2 to 5, the grinding wheel replacement support process will be described using as an example a case in which wafers W (wafer Wa, wafer Wc, wafer Wb) are held on each of three chuck tables (chuck table 21, chuck table 22, chuck table 23) provided on the turntable 20.

[0033] In addition to the above-described configuration, the grinding device 1 is equipped with a distance recognition unit 91 and a distance recognition unit 92. The distance recognition unit 91 is a first distance recognition unit that recognizes the distance between the holding surface of the chuck table at the first grinding position and the upper surface of the grinding wheel 55 (the lower surface of the wheel base 54). The distance recognition unit 92 is a second distance recognition unit that recognizes the distance between the holding surface of the chuck table at the second grinding position and the upper surface of the grinding wheel 55 (the lower surface of the wheel base 84).

[0034] 2, the distance recognition unit 91 is configured to recognize the distance between the holding surface 220 and the upper surface of the grinding wheel 55 based on the feed position of the grinding mechanism 50 by the feed mechanism 40 when the grinding mechanism 50 grinds the wafer W to a predetermined thickness. More specifically, the distance recognition unit 91 may recognize the distance between the holding surface 220 and the upper surface of the grinding wheel 55 (i.e., the thickness of the grinding wheel 55) based on the feed position when the thickness of the wafer W measured using a height gauge (not shown) or the like reaches the predetermined thickness. In the grinding apparatus 1, it can be determined that the shorter the distance recognized by the distance recognition unit 91, the more worn the grinding wheel 55 is.

[0035] 2, the distance recognition unit 92 is configured to recognize the distance between the holding surface 230 and the upper surface of the grinding wheel 85 based on the feed position of the grinding mechanism 80 by the feed mechanism 70 when the grinding mechanism 80 grinds the wafer W to the finish thickness. More specifically, the distance recognition unit 92 may recognize the distance between the holding surface 230 and the upper surface of the grinding wheel 85 (i.e., the thickness of the grinding wheel 85 or the extension amount of the grinding wheel 85 extending from the wheel base) based on the feed position when the thickness of the wafer W measured using a height gauge (not shown) or the like reaches the finish thickness. In the grinding apparatus 1, it can be determined that the shorter the distance recognized by the distance recognition unit 92, the more worn the grinding wheel 85 is.

[0036] When the control unit 90 determines that either of the grinding holes needs to be replaced based on the distance recognized by the distance recognition unit (distance recognition unit 91, distance recognition unit 92) during grinding processing, it suspends part or all of the series of fully automatic processes and assists the user in replacing the grinding wheel and subsequent operations. This will be described in more detail below.

[0037] In the grinding apparatus 1, in a series of fully automated processes, the grinding mechanism 50 and the grinding mechanism 80 simultaneously grind the wafer W in parallel. The control unit 90 monitors the distances recognized by the distance recognition unit 91 and the distance recognition unit 92 during the grinding processes by the grinding mechanism 50 and the grinding mechanism 80. Then, for example, as shown in Fig. 2, when the grinding wheel 85 of the grinding mechanism 80 is worn out and the distance recognized by the distance recognition unit 92 reaches a preset grinding wheel limit value (i.e., the distance becomes equal to or less than a certain threshold), the control unit 90 controls the grinding mechanism 80, whose distance has reached the grinding wheel limit value, to a state in which the grinding wheel 83 can be replaced.

[0038] 3, the rotation of the spindle 81 is stopped, and the grinding mechanism 80 is raised by the feed mechanism 70 to separate it from the wafer Wb held on the chuck table 23. At this time, the control unit 90 may more directly prompt the user to replace the grinding wheel 83, for example, by displaying a predetermined screen on a monitor (not shown). Note that the notification to the user that the grinding wheel 83 should be replaced may be notified to the user by using other devices such as a speaker or a lamp, instead of a monitor.

[0039] While controlling the grinding mechanism 80 as described above, the control unit 90 does not interrupt the grinding process by the grinding mechanism 50, and causes the grinding mechanism 50 to continue the grinding process until the wafer Wc reaches a predetermined thickness. Furthermore, the control unit 90 causes the carry-out mechanism 18 to carry out the ground wafer Wa held on the chuck table 21 located at the carry-in / out position from the chuck table 21 and move it to the cleaning mechanism 16. This puts the chuck table 21 into an empty state where no wafer is held on it.

[0040] 4, the user replaces the worn grinding wheel 83 attached to the grinding mechanism 80 with a new grinding wheel 86. The grinding wheel 86 has unworn grinding stones 88 arranged in a ring shape on a wheel base 87. During this time, the control unit 90 controls the cleaning mechanism 16 to clean the wafer Wa, and when cleaning is complete, controls the robot hand 12 to store the wafer Wa in the cassette 19. Furthermore, when the wafer Wc reaches a predetermined thickness and grinding is complete, the control unit 90 stops the rotation of the spindle 51 and uses the feed mechanism 40 to raise the grinding mechanism 50 and separate it from the wafer Wc held on the chuck table 22. This controls the turntable 20 to a rotatable state.

[0041] When the control unit 90 detects, either by a predetermined user operation or automatically, that the grinding wheel has been replaced in one grinding mechanism 80 and that the grinding process has been completed in the other grinding mechanism 50, it rotates the turntable 20 as shown in FIG. 5 to move the empty chuck table 21 that is not holding a wafer to directly below the grinding mechanism 80 whose grinding wheel has been replaced, thereby completing the replacement assistance process.

[0042] As described above, the grinding device 1 can determine when a grinding wheel needs to be replaced, and when a grinding wheel replacement is necessary, the grinding mechanism that requires the grinding wheel replacement is controlled to a state where the grinding wheel replacement is possible, that is, a state where the user can immediately begin the replacement work. This makes it possible to make the user aware of the need to replace the grinding wheel and encourage them to do so, and also makes it possible to smoothly complete the actual replacement work in a short time. Therefore, the grinding device 1 can shorten the time from when a grinding wheel replacement is necessary to when the replacement is completed compared to conventional methods.

[0043] Typically, when a grinding wheel is replaced, the grinding wheel of the new grinding wheel is dressed with a dressing wheel, followed by various setup procedures to return to a fully automated process. Among these, dressing is performed to ensure the grinding wheel fully demonstrates its performance. In the grinding apparatus 1, when the grinding wheel is replaced, a preparation process for dressing is automatically performed. Specifically, the grinding apparatus 1 controls the rotation of the turntable 20 to move the chuck table 21, which has previously been emptied of wafers to hold the dressing wheel, directly beneath the grinding wheel requiring dressing. This allows the user to complete preparation for dressing simply by placing the dressing wheel on the empty chuck table, allowing the grinding apparatus 1 to begin the dressing process promptly. Therefore, the grinding apparatus 1 can shorten the time from grinding wheel replacement to the completion of dressing compared to conventional methods, thereby enabling an earlier return to fully automated processing.

[0044] As described above, with the grinding device 1 according to this embodiment, it is possible to shorten the period from when the need for changing the grinding wheel is recognized and full-automatic processing is interrupted, through the replacement of the grinding wheel and subsequent processing (e.g., dressing, setup, etc.), until the interrupted full-automatic processing is resumed, and therefore the downtime associated with changing the grinding wheel (grinding wheel) can be shortened.

[0045] Furthermore, according to the grinding device 1 of this embodiment, the motorized parts (such as the grinding mechanism and turntable) of the grinding device 1 are automatically controlled to a state corresponding to the work to be performed by the user. This reduces the workload on the user and also reduces the time wasted due to the user not being able to recognize the work to be performed. Therefore, in addition to the effect of reducing the processing time itself through automation, the effect of reducing the time until the user starts work can also be expected, so that downtime can be reduced more than the time reduction obtained by simply automating the process, while reducing the burden on the user.

[0046] Furthermore, unlike the grinding device described in Patent Document 1, which synchronizes the timing of grinding wheel replacement across multiple grinding mechanisms, the grinding device 1 shortens overall downtime by shortening the downtime associated with each grinding wheel replacement. Therefore, there is no need to increase the wear rate of the grinding wheels in some of the grinding mechanisms beyond the standard in order to synchronize the timing of replacement of multiple grinding wheels. Therefore, the average replacement frequency of each grinding wheel can be reduced compared to the grinding device described in Patent Document 1.

[0047] In the above-described embodiment, the control unit 90 removes a wafer from a chuck table to create an empty state, and then, after replacing the grinding wheel, moves the empty chuck table directly below the grinding mechanism whose grinding wheel has been replaced. However, if there is a chuck table that does not hold a wafer, the control unit 90 may move the chuck table directly below the grinding mechanism whose grinding wheel has been replaced after replacing the grinding wheel. That is, when the wear of the grinding wheel reaches its limit, the control unit 90 only needs to perform at least the following processes: control the grinding mechanism to a state where the grinding wheel can be replaced; and move the chuck table that does not hold a wafer directly below the grinding mechanism after the grinding wheel has been replaced. Furthermore, if all of the chuck tables on the turntable are holding wafers, the control unit 90 may further perform the process of removing a wafer from one of the chuck tables before moving the chuck table that does not hold a wafer directly below the grinding mechanism after the grinding wheel has been replaced.

[0048] (Second embodiment) Fig. 6 is a perspective view of the grinding apparatus 2 according to this embodiment. The grinding apparatus 2 shown in Fig. 6 is a fully automatic processing apparatus, similar to the grinding apparatus 1 according to the first embodiment, and is configured to automatically perform a series of operations for a wafer W, which is a workpiece, including a loading process, a rough grinding process, a finish grinding process, a cleaning process, and a loading process.

[0049] As shown in Figure 6, the grinding device 2 differs from the grinding device 1 in that it is equipped with a dressing wheel storage section 100 that stores a dressing wheel 101 in the space between the positioning mechanism 13 and the cleaning mechanism 16, and in that the grinding device 2 also performs dressing during the replacement assistance process.

[0050] 7 to 14 are diagrams illustrating the grinding wheel replacement support process in the grinding apparatus 2. FIG. 7 illustrates the detection of wear on the grinding wheel, FIG. 8 illustrates the retraction of the grinding mechanism, FIG. 9 illustrates the replacement of the grinding wheel, and FIG. 10 illustrates the placement of the dressing wheel on the chuck table. FIG. 11 illustrates the rotation of the turntable, FIG. 12 illustrates the dressing process, FIG. 13 illustrates the rotation of the turntable, and FIG. 14 illustrates the removal of the dressing wheel from the chuck table. Hereinafter, with reference to FIGS. 7 to 14, the grinding wheel replacement support process performed in the grinding apparatus 2 when replacing the grinding wheel will be described using an example in which wafers W (wafer Wa, wafer Wc, wafer Wb) are held on three chuck tables (chuck table 21, chuck table 22, chuck table 23) provided on the turntable 20, respectively.

[0051] In the grinding apparatus 2, in a series of processes that are performed fully automatically, the grinding mechanism 50 and the grinding mechanism 80 simultaneously grind the wafer W in parallel. At this time, the dressing wheel 101 is housed in the dressing wheel housing unit 100, as shown in FIG. 7. During the grinding processes by the grinding mechanism 50 and the grinding mechanism 80, the control unit 90 monitors the distances recognized by the distance recognition units 91 and 92. Then, for example, as shown in FIG. 7, when the grinding wheel 85 of the grinding mechanism 80 is worn and the distance recognized by the distance recognition unit 92 reaches a preset grinding wheel limit value (i.e., the distance becomes equal to or less than a certain threshold), the control unit 90 controls the grinding mechanism 80, whose distance has reached the grinding wheel limit value, to a state in which the grinding wheel 83 can be replaced.

[0052] 8, the rotation of the spindle 81 is stopped, and the grinding mechanism 80 is raised by the feed mechanism 70 to separate it from the wafer Wb held on the chuck table 23. At this time, the control unit 90 may more directly prompt the user to replace the grinding wheel 83 by, for example, displaying a predetermined screen on a monitor (not shown).

[0053] While controlling the grinding mechanism 80 as described above, the control unit 90 does not interrupt the grinding process by the grinding mechanism 50, and causes the grinding mechanism 50 to continue the grinding process until the wafer Wc reaches a predetermined thickness. Furthermore, the control unit 90 causes the carry-out mechanism 18 to carry out the ground wafer Wa held on the chuck table 21 located at the carry-in / out position from the chuck table 21 and move it to the cleaning mechanism 16. This puts the chuck table 21 into an empty state where no wafer is held on it.

[0054] 9, the user replaces the worn grinding wheel 83 attached to the grinding mechanism 80 with a new grinding wheel 86. During this time, the control unit 90 controls the cleaning mechanism 16 to clean the wafer Wa, and when cleaning is complete, controls the robot hand 12 to store the wafer Wa in the cassette 19. After the wafer Wa is moved to the cassette 19, the unloading mechanism 18 transports the dressing wheel 101 stored in the dressing wheel storage unit 100 to the cleaning mechanism 16. When the wafer Wc reaches a predetermined thickness and grinding is completed, the control unit 90 stops the rotation of the spindle 51 and causes the feed mechanism 40 to lift the grinding mechanism 50 away from the wafer Wc held on the chuck table 22. This controls the turntable 20 to a rotatable state.

[0055] 10, the control unit 90 causes the unloading mechanism 18 to load the dressing wheel 101 from the cleaning mechanism 16 onto the chuck table 21, which has been vacant since the wafer Wa was unloaded, and causes the chuck table 21 to hold the dressing wheel 101. Thereafter, when the control unit 90 detects, either by a predetermined user operation or automatically, that the grinding wheel has been replaced in one grinding mechanism 80, the grinding process has been completed in the other grinding mechanism 50, and the dressing wheel 101 has been held on the chuck table 21, the control unit 90 rotates the turntable 20 to move the chuck table 21 holding the dressing wheel 101 to directly below the grinding mechanism 80 whose grinding wheel has been replaced, as shown in FIG.

[0056] When the dressing wheel 101 moves directly below the grinding mechanism 80, the control unit 90 starts rotating the spindle 81 as shown in Figure 12, and lowers the grinding mechanism 80 using the feed mechanism 70, dressing the grinding wheel 88 of the grinding wheel 86 newly attached to the grinding mechanism 80 with the dressing wheel 101.

[0057] 13, when the dressing is completed, the control unit 90 stops the rotation of the spindle 81 and causes the feed mechanism 70 to raise the grinding mechanism 80 and move it away from the dressing grindstone 101 held on the chuck table 23. Thereafter, the control unit 90 rotates the turntable 20 again to move the chuck table 21 holding the dressing grindstone 101 to the carry-in / out position.

[0058] When the chuck table 21 moves to the carry-in / out position, the control unit 90 causes the carry-out mechanism 18 to store the dress grindstone 101 in the dress grindstone storage unit 100, as shown in FIG. 14, and ends the replacement support process.

[0059] As described above, according to the grinding device 2, similar to the grinding device 1, it is possible to shorten the period from when the need for grinding wheel replacement is recognized and fully automatic processing is interrupted, through the replacement of the grinding wheel and subsequent processing (e.g., dressing, setup, etc.), until the interrupted fully automatic processing is resumed, thereby shortening the downtime associated with replacing the grinding wheel (grinding wheel). In particular, with the grinding device 2, because the grinding stone of the replaced grinding wheel is automatically dressed, the time from replacing the grinding wheel to completing dressing can be further shortened than with the grinding device 1 according to the first embodiment.

[0060] The grinding apparatus 2 may further include an auto-setup unit that automatically performs various setups required after dressing and before returning to normal operation. By including the auto-setup unit, the grinding apparatus 2 may be configured to automatically return to fully automatic processing after changing the grinding wheel by automating setup as well as dressing.

[0061] (Third embodiment) Fig. 15 is a perspective view of the grinding apparatus 3 according to this embodiment. The grinding apparatus 3 shown in Fig. 15 is a fully automatic processing apparatus, similar to the grinding apparatus 2 according to the second embodiment, and is configured to automatically perform a series of operations including a loading process, a rough grinding process, a finish grinding process, a cleaning process, and a loading process for a wafer W, which is a workpiece.

[0062] Grinding device 3 differs from grinding device 2 in that, while the above-mentioned grinding device 2 is a two-axis, three-chuck type grinding device with two grinding mechanisms and three chuck tables, grinding device 3 is a four-axis, five-chuck type grinding device with four grinding mechanisms and five chuck tables.

[0063] Other features are the same as those of the grinding apparatus 2. Specifically, the grinding apparatus 2 is similar to the grinding apparatus 2 in that it has two cassettes (cassette 111, cassette 119) in front of the base 110, into which wafers W are loaded and unloaded by a robot hand 112, that it has a positioning mechanism 113 and a cleaning mechanism 116 in front of the turntable 120, that it has a dress grindstone accommodating section 200 that accommodates a dress grindstone 201 between the positioning mechanism 113 and the cleaning mechanism 116, and that the wafers W are transported between the positioning mechanism 113, the cleaning mechanism 116, and the dress grindstone accommodating section 200 and the chuck tables (chuck table 121, chuck table 122, chuck table 123, . . . , chuck table 125) provided on the turntable 120 by a load mechanism 117 and a load mechanism 118.

[0064] Above the turntable 120, there are provided four grinding mechanisms (grinding mechanism 151, grinding mechanism 152, grinding mechanism 153, grinding mechanism 154), which can be raised and lowered by feed mechanisms (feed mechanism 141, feed mechanism 142, feed mechanism 143, feed mechanism 144) supported by columns (column 131, column 132, column 133, column 134).

[0065] The grinding device 3 also has a distance recognition unit (not shown), and when it detects that the wear of the grinding wheel of any of the grinding mechanisms has reached its limit during grinding based on the distance recognized by the distance recognition unit, it performs the same processing as the grinding device 2 under the control of the control unit 190. That is, the grinding device 3 makes the grinding wheel replaceable, and after the replacement, moves the dressing wheel 201 directly below the replaced grinding wheel to perform dressing. In this way, like the grinding device 2, the grinding device 3 can also reduce the downtime associated with replacing worn grinding wheels (grinding wheels 161, 162, 163, and 164).

[0066] The embodiments of the present invention are not limited to the above-described embodiments, and may be variously modified, substituted, or altered without departing from the spirit and scope of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention.

[0067] In the above-described embodiment, an example of replacing the grinding wheel of the finish grinding mechanism is shown, but the grinding wheel to be replaced may be one whose grinding stone has reached its wear limit, and the grinding wheel of the rough grinding mechanism may also be replaced.

[0068] In the above-described embodiment, an example is shown in which the dressing stone is moved directly below the replaced grinding wheel and dressing is performed automatically, but the dressing itself may be started by user operation, or, as with grinding wheel replacement, the process up to the point where dressing can be started may be automated.

[0069] In the above-described embodiments, a two-axis, three-chuck grinding machine and a four-axis, five-chuck grinding machine are exemplified, but the number of grinding mechanisms and chuck tables is not limited to these examples. Any grinding machine having a plurality of grinding mechanisms and a plurality of chuck tables may be used. [Industrial Applicability]

[0070] As described above, the grinding device equipped with multiple grinding mechanisms of the present invention can reduce downtime associated with changing grinding wheels, and is useful in grinding devices where high throughput is expected, particularly in fully automatic grinding devices. [Explanation of symbols]

[0071] 1, 2, 3: grinding device, 11, 19, 111, 119: cassette, 16, 116: cleaning mechanism, 17, 117: loading mechanism, 18, 118: unloading mechanism, 20, 120: turntable, 21, 22, 23, 121, 122, 123, 125: chuck table, 40, 70, 141, 142, 143, 144: feeding mechanism, 50, 80, 151, 152, 153, 154: grinding Grinding mechanism, 51, 81: spindle, 52, 82: mount, 53, 83, 161, 162, 163, 164: grinding wheel, 54, 84: wheel base, 55, 85: grinding stone, 90, 190: control unit, 91, 92: distance recognition unit, 100, 200: dressing stone storage unit, 101, 201: dressing stone, 210, 220, 230: holding surface, W, Wa, Wb, Wc: wafer

Claims

1. a holding mechanism that holds and rotates the wafer by a holding surface; a turntable on which at least three of the holding mechanisms are arranged and which rotates; a first grinding mechanism equipped with a first grinding wheel having an annular first grinding stone disposed thereon for grinding the wafer; a second grinding mechanism equipped with a second grinding wheel having a second annular grinding stone disposed thereon for grinding the wafer; a first grinding feed mechanism that feeds the first grinding mechanism in a direction perpendicular to the holding surface; a second grinding feed mechanism that feeds the second grinding mechanism in a direction perpendicular to the holding surface; a first distance recognition unit that recognizes the distance between the holding surface and an upper surface of the first grinding wheel; a second distance recognition unit that recognizes the distance between the holding surface and an upper surface of the second grinding wheel; a loading mechanism for loading the wafer into the holding mechanism; a carry-out mechanism that carries out the wafer held by the holding mechanism from the holding mechanism; A grinding device comprising at least When the first grinding mechanism and the second grinding mechanism are performing grinding, if the distance recognized by the first distance recognition unit or the second distance recognition unit reaches a preset grinding wheel limit value, Putting the grinding mechanism, which is the first grinding mechanism or the second grinding mechanism, in which the distance has reached the grinding wheel limit value into a state in which the grinding wheel attached to the grinding mechanism can be replaced, If all of the holding mechanisms arranged on the turntable are holding wafers, the carrying-out mechanism carries the wafer out of one of the holding mechanisms arranged on the turntable; moving the holding mechanism not holding a wafer to directly below the grinding mechanism; A grinding device comprising a control unit.

2. A dressing stone accommodating section is provided for accommodating the dressing stone, The control unit If all three of the holding mechanisms are holding wafers, the wafer is unloaded from one of the holding mechanisms by the unloading mechanism; the dressing wheel accommodated in the dressing wheel accommodating section is held by the holding mechanism by the carrying-in mechanism or the carrying-out mechanism, and then the holding mechanism holding the dressing wheel is moved to immediately below the grinding mechanism to which the distance has reached the grinding wheel limit value; dressing a grinding wheel newly installed in the grinding mechanism; The grinding device according to claim 1.

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