Grinding device

Abstract

To suppress defects on the upper surface of a wafer in a grinding device.SOLUTION: A grinding device 1 includes a chuck table 10 for holding a wafer, a grinding mechanism 60 for grinding the wafer with a grinding wheel 66, and a processing chamber 31 for accommodating the chuck table 10 and the grinding wheel 66. The grinding device 1 includes a head portion 51 which is a cleaning water nozzle that supplies cleaning water to the upper surface of the wafer held on the chuck table 10 in the processing chamber 31 before grinding to clean the upper surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] BACKGROUND ART A grinding device is known that includes a rough grinding mechanism that performs grinding with a rough grinding wheel and a finish grinding mechanism that performs grinding with a finish grinding wheel having a smaller abrasive grain size than that of the rough grinding wheel (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-050944 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a grinding device, the wafer is first roughly ground by the rough grinding mechanism, and then finish ground by the finish grinding mechanism. If the finish grinding is performed while grinding debris generated during the rough grinding is still attached to the wafer, the grinding debris may become trapped between the bottom surface of the finish grinding wheel and the top surface of the wafer, causing deep scratches on the wafer.

[0005] The problem of grinding debris damaging wafers is not limited to grinding machines equipped with a rough grinding mechanism and a finish grinding mechanism, but can also occur in grinding machines equipped with a single grinding mechanism if particles such as grinding debris adhere to the top surface of the wafer before grinding.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a grinding device that suppresses defects on the upper surface of a wafer. [Means for solving the problem]

[0007] One aspect of the grinding apparatus of the present invention is a grinding apparatus comprising a chuck table for holding a wafer, a grinding mechanism for grinding the wafer with a grinding wheel, and a grinding chamber for accommodating the chuck table and the grinding wheel, and further comprising a cleaning water nozzle for supplying cleaning water to an upper surface of the wafer held on the chuck table in the grinding chamber before grinding to clean the upper surface.

[0008] Another embodiment of the grinding apparatus of the present invention is a grinding apparatus comprising a chuck table for holding a wafer, a turntable having three or more chuck tables and rotating around a central axis, a rough grinding mechanism for grinding the wafer with a rough grinding wheel, a finish grinding mechanism for grinding the wafer, which has been rough ground with the rough grinding wheel, with a finish grinding wheel, a rough grinding chamber for accommodating the chuck table and the rough grinding wheel, and a finish grinding chamber for accommodating the chuck table and the finish grinding wheel, and at least one of the rough grinding chamber and the finish grinding chamber is provided with a cleaning water nozzle for supplying cleaning water to the upper surface of the wafer to clean the upper surface of the wafer before grinding the wafer held on the chuck table with the finish grinding wheel. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a grinding device that suppresses defects on the upper surface of a wafer. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of a grinding device according to a first embodiment. [Figure 2] 2 is an enlarged view of the vicinity of a chuck table of the grinding machine according to the first embodiment. FIG. [Figure 3] 2 is a cross-sectional schematic view of a non-contact thickness measuring device provided in the grinding device according to the first embodiment. FIG. [Figure 4] FIG. 10 is a cross-sectional schematic view of a non-contact thickness measuring device according to a modified example. [Figure 5] FIG. 10 is a perspective view of a grinding device according to a second embodiment. [Figure 6] FIG. 10 is a perspective view of a grinding device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Fig. 1 is a perspective view of a grinding apparatus 1 according to this embodiment. The X-axis, Y-axis, and Z-axis directions shown in Fig. 1 are perpendicular to one another. The X-axis and Y-axis directions are substantially horizontal, and the Z-axis direction is the up-down direction (substantially vertical).

[0012] 1, the grinding apparatus 1 is a grinding apparatus that includes a chuck table 10 that holds a wafer W (see FIG. 3), a grinding mechanism 60 that grinds the wafer W with a grinding wheel 66, and a processing chamber 31 that houses the chuck table 10 and the grinding wheel 66 provided in the grinding mechanism 60. The grinding apparatus 1 is configured to perform grinding processing on the wafer W held on the chuck table 10 using the grinding mechanism 60 within the processing chamber 31 that is partitioned by a processing chamber cover 30. In other words, the processing chamber 31 is a grinding chamber.

[0013] The grinding apparatus 1 further includes a non-contact thickness gauge 50 that functions as a cleaning water nozzle that supplies cleaning water to the upper surface of the wafer W before grinding to clean the upper surface. The grinding apparatus 1 is configured to clean the upper surface of the wafer W held on the chuck table 10 in the processing chamber 31 using the non-contact thickness gauge 50 before performing grinding processing using the grinding mechanism 60.

[0014] The wafer W processed by the grinding apparatus 1 is, for example, a semiconductor wafer such as silicon or gallium arsenide, but is not limited to these. The wafer may also be a ceramic, glass, or sapphire-based optical device wafer.

[0015] The grinding apparatus 1 according to this embodiment will be described in detail below with reference to Fig. 1. A rectangular opening extending in the Y-axis direction is formed on the upper surface of a base 4 of the grinding apparatus 1. As shown in Fig. 1, a chuck table 10, a table rotation mechanism 15, and a movement mechanism 20 are placed inside the opening. This opening is covered by a bellows-shaped waterproof cover 6 that is movable together with the chuck table 10.

[0016] The chuck table 10 has a holding surface 111 for holding a wafer W, which is a workpiece, and suction-holds the wafer W placed on the holding surface 111. The chuck table 10 includes a frame 12 having a recess formed therein and a circular porous plate 11 embedded in the recess of the frame 12. The frame 12 has a flow path formed therein that connects the recess of the frame 12 to a suction source (not shown). The upper surface of the porous plate 11 exposed from the frame 12 is the holding surface 111, which is formed to be flush with the upper surface of the frame 12. The wafer W is placed on the holding surface 111 with its back surface, on which no devices are formed, facing upward. Note that a tape T (see FIG. 3) for protecting the devices may be attached to the front surface of the wafer W on which devices are formed. The chuck table 10 suction-holds the wafer W by generating a suction force on the holding surface 111 when a suction source (not shown) performs a suction operation.

[0017] The table rotation mechanism 15 is a mechanism that rotates the chuck table 10 and supports the chuck table 10 from below. The table rotation mechanism 15 is configured to be rotatable around a rotation axis that runs along the Z-axis direction and passes through the center of the chuck table 10. The table rotation mechanism 15 rotates the chuck table 10 that is connected to the table rotation mechanism 15.

[0018] The moving mechanism 20 is a mechanism for moving the chuck table 10 in the Y-axis direction, and is, for example, a ball screw type electric slider. The moving mechanism 20 includes a ball screw 21 and a guide rail 22 extending in the Y-axis direction, a motor 23 connected to one end of the ball screw 21, and a slide unit 24 slidably installed on the guide rail 22. A nut unit (not shown) that is threadedly engaged with the ball screw 21 is formed on the back surface of the slide unit 24. In the moving mechanism 20, the slide unit 24 moves in the Y-axis direction due to rotation of the motor 23, and accordingly, the chuck table 10 fixed to the slide unit 24 moves in the Y-axis direction.

[0019] A column 5 is erected on the upper surface of the base 4. As shown in Fig. 1, a grinding mechanism 60 and a processing feed mechanism 70 are provided on the front surface of the column 5 extending upward from the upper surface of the base 4. The grinding device 1 further includes a control unit 90 that controls the operation of each part of the grinding device 1.

[0020] The processing feed mechanism 70 is a mechanism that feeds the grinding mechanism 60 in the Z-axis direction for processing, and is, for example, a ball screw type electric slider. The processing feed mechanism 70 includes a ball screw 71 and guide rail 72 that extend in the Z-axis direction, a motor 73 connected to one end of the ball screw 71, and a Z-axis stage 74 that is slidably installed on the guide rail 72. A nut portion (not shown) that is threaded onto the ball screw 71 is formed on the rear side of the Z-axis stage 74. In the processing feed mechanism 70, the Z-axis stage 74 moves in the Z-axis direction due to rotation of the motor 73, and accordingly, the grinding mechanism 60 fixed to the Z-axis stage 74 moves in the Z-axis direction along the guide rail 72.

[0021] The grinding mechanism 60 is a mechanism for grinding a wafer W held on the chuck table 10, and includes a spindle unit 61, a mount 62 provided at the lower end of the spindle unit 61, a holder 63 surrounding the spindle unit 61 and fixed to a Z-axis stage 74, and a grinding wheel 64 held on the underside of the mount 62. The grinding mechanism 60 is configured to rotate the grinding wheel 64 around its central axis using the spindle unit 61. The grinding wheel 64 is provided with a wheel base 65 and multiple grinding wheels 66 arranged in a ring shape on the underside of the wheel base 65. The multiple grinding wheels 66 are formed, for example, by bonding diamond abrasive grains with a bonding agent such as a vitrified bond.

[0022] The control unit 90 includes a processor 91 and a memory 92. The memory 92 stores various parameters, programs, and the like. The processor 91 executes the programs stored in the memory to control the operation of each component of the grinding apparatus 1. For example, the grinding process is performed in the grinding apparatus 1 when the processor 91 executes the programs. More specifically, the processor 91 rotates the grinding wheel 64 at high speed using the spindle unit 61 and rotates the chuck table 10 holding the wafer W at low speed in the same direction using the table rotation mechanism 15. Furthermore, the processor 91 moves the grinding wheel 64 in the Z-axis direction using the processing feed mechanism 70 so that the grinding stone 66 of the rotating grinding wheel 64 contacts the backside of the wafer W held on the chuck table 10. As a result, in the grinding apparatus 1, the grinding process is performed by the grinding mechanism 60 to grind the backside of the wafer W. During the grinding process, grinding water is supplied to the wafer W from the wheel base 65 of the grinding wheel 64.

[0023] Fig. 2 is an enlarged view of the vicinity of the chuck table 10 of the grinding apparatus 1 according to this embodiment. Fig. 3 is a cross-sectional schematic view of a non-contact thickness measuring device 50 provided in the grinding apparatus 1 according to this embodiment. The configuration around the chuck table 10 will be described below with reference to Figs. 1 to 3.

[0024] 1, the grinding apparatus 1 further includes a processing chamber cover 30, a contact thickness gauge 40, and a non-contact thickness gauge 50 on the upper surface of the base 4. The contact thickness gauge 40 is a gauge that measures the thickness of the wafer W held on the holding surface 111 of the chuck table 10 by contact, and the non-contact thickness gauge 50 is a gauge that measures the thickness of the wafer W held on the holding surface 111 of the chuck table 10 by non-contact. Both the contact thickness gauge 40 and the non-contact thickness gauge 50 are provided in the processing chamber 31 formed by the processing chamber cover 30.

[0025] The processing chamber cover 30 is a cover that covers the processing chamber 31, which is a processing space where the wafer W is processed by the grinding mechanism 60. A spindle unit 61 is inserted into a through-hole (not shown) provided on the upper surface of the processing chamber cover 30, thereby accommodating a grinding wheel 64 of the grinding mechanism 60 inside the processing chamber 31. A gap is also formed below the front (-Y axis direction) side wall of the processing chamber cover 30. The chuck table 10 moves from outside the processing chamber 31 into the processing chamber 31 through the gap formed in the processing chamber cover 30, and is positioned at a grinding position below the grinding mechanism 60.

[0026] 1 and 2, the contact thickness measuring device 40 includes a height gauge 41 and a height gauge 42. Both the height gauge 41 and the height gauge 42 are supported by an L-shaped arm fixed to the upper surface of the base 4. The height gauge 41 is positioned above the frame 12 when the chuck table 10 is in a predetermined position. In contrast, the height gauge 42 is positioned above the porous plate 11 when the chuck table 10 is in a predetermined position.

[0027] The height gauge 41 is a height gauge that measures the height of the upper surface of the frame 12, which is equal to the height of the holding surface 111, by detecting contact with the holding surface 111. In contrast, the height gauge 42 is a height gauge that measures the height of the upper surface Wa (see FIG. 3) of the wafer W placed on the porous plate 11 by detecting contact with the upper surface Wa.

[0028] The contact thickness measuring device 40 calculates the thickness of the wafer W based on the difference between the heights measured by the height gauge 41 and the height gauge 42. For example, if protective tape T (see FIG. 3) is attached to the wafer W, the contact thickness measuring device 40 may calculate the thickness of the wafer W by subtracting the known thickness of the tape T from the difference between the heights measured by the height gauge 41 and the height gauge 42.

[0029] 1 and 2, the non-contact thickness measuring device 50 includes a head unit 51 fixed to an L-shaped arm and a motor 52 that rotates the L-shaped arm around the Z axis. The head unit 51 is attached to the tip of the L-shaped arm that extends from the upper surface of the base 4. The head unit 51 moves between above the chuck table 10 and other positions by the rotation of the motor 52 provided inside the base 4.

[0030] 3, head unit 51 includes measurement unit 510 and photometric protection unit 520, which are separated by cover glass 530. Housing 511 of measurement unit 510 contains light-emitting unit 512, half mirror 513, and light-receiving unit 514. Housing 521 of photometric protection unit 520 has water reservoir 525 therein for temporarily storing water, supply port 522 connected to water supply source 53 formed on the side, and opening 523 formed on the bottom surface 524. That is, the bottom of head unit 51 is provided with water reservoir 525 for temporarily storing water, supply port 522 for supplying water from water supply source 53 to water reservoir 525, and opening 523 for supplying water from water reservoir 525 to top surface Wa of wafer W.

[0031] The motor 52 that rotates the L-shaped arm that supports the head portion 51 is a radial movement mechanism that moves the head portion 51 in the radial direction of the holding surface 111 of the chuck table 10, and moves the head portion 51 above the chuck table 10 in a direction approximately parallel to the holding surface 111.

[0032] 3, with the head unit 51 positioned above the wafer W by the motor 52, the water supply source 53 supplies water into the housing 521 via the supply port 522. Furthermore, water is supplied via the supply port 522 and the opening 523 to the space between the lower surface 524 of the head unit 51 and the upper surface Wa of the wafer W, thereby filling the space between the lower surface 524 and the upper surface Wa with water and forming a water layer L. With the water layer L formed, the light-emitting unit 512 emits light, causing laser light to exit the head unit 51 via the half mirror 513, the cover glass 530, and the opening 523 and then irradiate the wafer W through the water layer L. A portion of the laser light irradiated onto the wafer W is reflected by the upper surface Wa and the lower surface Wb of the wafer W, re-enters the head unit 51, and is guided to the light-receiving unit 514 via the half mirror 513.

[0033] In the non-contact thickness measuring device 50, the head unit 51 disposed above the wafer W calculates the thickness of the wafer W based on the optical path difference of the laser light reflected from each of the upper surface Wa and the lower surface Wb of the wafer W, detected by the light receiving unit 514, when a water layer L is formed between the lower surface 524 and the upper surface Wa. Although not particularly limited, the head unit 51 may be, for example, a spectroscopic interference wafer thickness gauge that measures the thickness of the wafer W by analyzing the interference light of the laser light reflected from each of the upper surface Wa and the lower surface Wb. That is, the head unit 51 is a non-contact measuring unit that measures the thickness of the wafer W held on the holding surface 111 of the chuck table 10, and also a water layer forming unit that is disposed above the wafer W and forms a water layer L between the lower surface 524 of the head unit 51 and the upper surface Wa of the wafer W, filling the gap with water.

[0034] In this way, the non-contact thickness measuring device 50 measures the thickness of the wafer W with the water layer L formed between the lower surface 524 and the upper surface Wa. Therefore, even when the thickness of the wafer W is measured during the grinding process of the wafer W, the measurement light is not blocked by sprays of grinding water that are scattered during the grinding process, and the grinding apparatus 1 makes it possible to measure the thickness of the wafer W with high accuracy.

[0035] In the grinding apparatus 1, the non-contact thickness gauge 50 is used not only to measure the thickness of the wafer W but also to clean the upper surface Wa of the wafer W. In other words, the head unit 51, which is the water layer forming unit, is also used as a cleaning water nozzle that supplies cleaning water to the upper surface Wa of the wafer W to clean the upper surface Wa of the wafer W. Cleaning of the upper surface Wa of the wafer W using the non-contact thickness gauge 50 will be described below.

[0036] Cleaning of the upper surface Wa of the wafer W using the non-contact thickness measuring device 50 is performed on the wafer W before grinding. Specifically, by executing the program by the processor 91, in the grinding apparatus 1, cleaning of the upper surface Wa of the wafer W is performed using the head portion 51 (water layer forming portion) of the non-contact thickness measuring device 50 as a cleaning water nozzle before grinding processing using the grinding mechanism 60, and then grinding processing is performed using the grinding mechanism 60.

[0037] More specifically, when the grinding device 1 is instructed to grind the wafer W, the processor 91 first controls the moving mechanism 20 to move the chuck table 10, which holds the wafer W by suction, to the grinding position. Then, the processor 91 controls the motor 52 to move the head unit 51 above the chuck table 10. When the head unit 51 is positioned above the chuck table 10, the upper surface Wa of the wafer W is cleaned.

[0038] To clean the upper surface Wa of the wafer W, the processor 91 controls the table rotation mechanism 15 to rotate the wafer W together with the chuck table 10 at high speed, and drives the motor 23 to move the chuck table 10, thereby positioning the head unit 51 directly above the center of the wafer W. Furthermore, the processor 91 starts the supply of water from the water supply source 53 to the non-contact thickness gauge 50, causing the head unit 51 to spray water onto the upper surface Wa of the wafer W held on the chuck table 10. The water sprayed from the opening 523 of the head unit 51 toward approximately the center of the upper surface Wa of the wafer W flows radially outward from the center over the upper surface Wa of the wafer W due to centrifugal force generated by the rotation of the chuck table 10, and finally falls off the wafer W and is drained away. At this time, grinding debris adhering to the upper surface Wa of the wafer W is also drained off the wafer W along with the water, thereby cleaning the upper surface Wa of the wafer W. That is, in the grinding apparatus 1, the upper surface Wa of the wafer W is spinner-cleaned with water discharged from the head portion 51. That is, the water is cleaning water.

[0039] During cleaning of the upper surface Wa of the wafer W, the processor 91 may control the motor 23 to reciprocate the chuck table 10 in the Y-axis direction. During cleaning of the upper surface Wa of the wafer W, the processor 91 may control the motor 52 to reciprocate the head unit 51 above the wafer W in an arc relative to the radial area of ​​the wafer.

[0040] Examples of grinding debris adhering to a wafer W before grinding include when grinding debris generated in a previous grinding process and adhering to the processing chamber cover 30 falls onto a wafer W moving into the processing chamber 31, or when grinding debris generated in a previous grinding process and remaining as a spray inside the processing chamber 31 adheres to a wafer W moving into the processing chamber 31.

[0041] When the cleaning is completed, the processor 91 controls the motor 52 to retract the head unit 51 from above the chuck table 10, and further, if the chuck table 10 is deviated from the grinding position, moves the chuck table 10 to the grinding position. Thereafter, grinding processing is performed using the grinding mechanism 60, and the upper surface Wa of the wafer W is ground by the grinding wheel 66.

[0042] As described above, in the grinding apparatus 1 according to this embodiment, the upper surface Wa of the wafer W is cleaned before the grinding process, and therefore it is possible to avoid starting the grinding process with grinding debris remaining on the upper surface Wa of the wafer W. This makes it possible to significantly prevent situations in which grinding debris gets caught between the grinding wheel 66 and the upper surface Wa of the wafer W, causing deep scratches on the wafer W during the grinding process. Therefore, the grinding apparatus 1 can prevent defects on the upper surface Wa of the wafer W.

[0043] Furthermore, the grinding apparatus 1 utilizes the configuration of an existing grinding apparatus to clean the top surface Wa of the wafer W before grinding. Specifically, the head 51 of a non-contact thickness gauge 50, which is positioned above the wafer W and measures the thickness of the wafer W, is used as a cleaning water nozzle. In existing grinding apparatuses, the non-contact thickness gauge 50 continuously measures the thickness of the wafer W during grinding by forming a water layer L. However, in the grinding apparatus 1, the non-contact thickness gauge 50's function of supplying water to the top surface Wa of the wafer W is utilized to clean the top surface Wa of the wafer W before grinding. In this way, by using the head 51 of the non-contact thickness gauge 50 as a cleaning water nozzle, the top surface Wa of the wafer W can be cleaned before grinding by simply modifying the control program of the existing grinding apparatus without changing the physical configuration of the apparatus. In other words, application to existing grinding apparatuses is relatively easy, and high technical effects can be obtained while effectively utilizing the user's existing assets, resulting in high cost-effectiveness.

[0044] Furthermore, in the grinding apparatus 1, the non-contact thickness measuring device 50 has a motor 52, which is a radial movement mechanism, so that the head unit 51, which is a water layer forming unit, can be easily positioned above the center of the chuck table 10, i.e., directly above the center of the wafer W. By positioning the head unit 51 directly above the center of the wafer W and spraying water, the water supplied from the head unit 51 to the upper surface Wa of the wafer W spreads uniformly radially outward from the center of the wafer W due to the centrifugal force caused by the rotation of the chuck table 10. This allows the entire upper surface Wa of the wafer W to be efficiently cleaned in a short time. Furthermore, by moving the head unit 51 back and forth above the wafer W, including directly above the center of the wafer W, the area directly hit by the water sprayed from the head unit 51 can be changed, thereby expanding the area on the upper surface Wa of the wafer W where a particularly strong cleaning power is applied.

[0045] FIG. 3 illustrates an example in which water supplied from a water supply source 53 is supplied to a water reservoir 525 in a housing 521 through a supply port 522. However, as shown in FIG. 4, the head unit 51 of the non-contact thickness gauge 50 may further include an air supply port 526 connected to an air source 54 for supplying air into the water reservoir 525. The head unit 51 may supply air together with water to the water reservoir 525 to create a mixed fluid within the water reservoir 525, and then supply the mixed fluid to the upper surface Wa through the opening 523 to clean the upper surface Wa of the wafer W with the mixed fluid. That is, the cleaning water supplied by the head unit 51, which is a cleaning nozzle, may contain air, and the water reservoir 525 may function as an air mixing unit that mixes air into the cleaning water. By performing two-fluid cleaning using a mixed fluid of water and air, it is possible to reduce the amount of water used and achieve high cleaning effectiveness while being environmentally friendly. The air may be supplied in the form of nanobubbles, and the upper surface Wa of the wafer W may be cleaned using nanobubble water, which is a mixed fluid containing nanobubbles, as cleaning water.

[0046] (Second embodiment) Fig. 5 is a perspective view of the grinding device 2 according to this embodiment. The X-axis, Y-axis, and Z-axis directions shown in Fig. 5 are perpendicular to one another. The X-axis and Y-axis directions are substantially horizontal, and the Z-axis direction is the up-down direction (substantially vertical).

[0047] The grinding apparatus 2 differs from the grinding apparatus 1 in that it is equipped with a grinding water nozzle 80 instead of the non-contact thickness measuring device 50, and in that during grinding, grinding water is supplied to the wafer W from the grinding water nozzle 80 instead of being supplied to the wafer W from the wheel base 65 of the grinding wheel 64. The grinding apparatus 2 also differs from the grinding apparatus 1 in that the grinding water nozzle 80 that supplies grinding water during grinding is used to clean the wafer W before grinding. That is, in the grinding apparatus 2, the grinding water nozzle 80 is used as a cleaning water nozzle.

[0048] The grinding water nozzle 80 is located inside the grinding stones 66 arranged in a circular ring shape on the grinding wheel 64 when viewed from above, and is configured to supply grinding water to the vicinity of the processing point of the wafer W during grinding. The processing point refers to a position on the upper surface Wa of the wafer W that corresponds approximately to the center of the chuck table 10.

[0049] The grinding apparatus 2 according to this embodiment also cleans the upper surface Wa of the wafer W before grinding, thereby preventing the start of grinding with grinding debris remaining on the upper surface Wa of the wafer W. Therefore, defects on the upper surface Wa of the wafer W can be suppressed. The grinding apparatus 2 is similar to the grinding apparatus 1 in that it cleans the upper surface Wa of the wafer W before grinding by utilizing a configuration (in this example, the grinding water nozzle 80) that is included in existing grinding apparatuses. Therefore, simply by modifying the control program of an existing grinding apparatus, it is possible to clean the upper surface of the wafer before grinding. Furthermore, similar to the grinding apparatus 1, it is possible to supply water near the center of the upper surface Wa of the wafer W and use centrifugal force to uniformly and efficiently clean the entire upper surface Wa of the wafer W.

[0050] (Third embodiment) Fig. 6 is a perspective view of the grinding device 3 according to this embodiment. The X-axis, Y-axis, and Z-axis directions shown in Fig. 6 are perpendicular to one another. The X-axis and Y-axis directions are substantially horizontal, and the Z-axis direction is the up-down direction (substantially vertical).

[0051] As shown in FIG. 6, the grinding device 3 is a grinding device that includes three chuck tables 10 for holding wafers W, a turntable 110 for rotating the chuck tables 10 around a central axis, a rough grinding mechanism 160 for grinding the wafers W with a rough grinding wheel 166, a finish grinding mechanism 260 for grinding the wafers W with a finish grinding wheel 266, a first processing chamber 131 that accommodates the chuck tables 10 and the rough grinding wheels 166, and a second processing chamber 132 that accommodates the chuck tables 10 and the finish grinding wheels 266.

[0052] The grinding apparatus 3 is configured to perform, for example, fully automatically, a series of processes on a wafer W, which is a workpiece, including a carry-in process, a grinding process (rough grinding, finish grinding), a cleaning process, and a carry-out process. In the grinding process, the grinding apparatus 3 is configured to perform rough grinding on the wafer W held on the chuck table 10 in the first processing chamber 131 using a rough grinding mechanism 160, and then perform finish grinding on the wafer W held on the chuck table 10 in the second processing chamber 132 using a finish grinding mechanism 260. In other words, the first processing chamber 131 is a rough grinding chamber, and the second processing chamber 132 is a finish grinding chamber.

[0053] The grinding device 3 further includes a non-contact thickness measuring device 150 having a head portion 151 that supplies cleaning water to the upper surface Wa of the wafer W and cleans the upper surface Wa of the wafer W before a rough grinding process in which the wafer W held on the chuck table 10 is ground by a rough grinding wheel 166, and a non-contact thickness measuring device 250 having a head portion 251 that supplies cleaning water to the upper surface Wa of the wafer W and cleans the upper surface Wa of the wafer W before a finish grinding process in which the wafer W held on the chuck table 10 is ground by a finish grinding wheel 266.

[0054] The grinding device 3 is configured to perform rough grinding using the rough grinding mechanism 160, and after the rough grinding, to clean the upper surface Wa of the wafer W in the first processing chamber 131 using the head part 151 of the non-contact thickness measuring device 150. Furthermore, before performing finish grinding using the finish grinding mechanism 260, the grinding device 3 is configured to clean the upper surface Wa of the wafer W held on the chuck table 10 in the second processing chamber 132 using the head part 251 of the non-contact thickness measuring device 250, and then perform finish grinding using the finish grinding mechanism 260.

[0055] The grinding apparatus 3 according to this embodiment will be described in further detail below with reference to Fig. 6. In addition to the chuck table 10, turntable 110, non-contact thickness gauge 150, rough grinding mechanism 160, non-contact thickness gauge 250, and finish grinding mechanism 260 described above, the grinding apparatus 3 also includes cassettes 101, 102, a robot hand 121, a positioning mechanism 122, a first transfer mechanism 123, a second transfer mechanism 124, a spinner cleaning device 125, a processing chamber cover 130, a contact thickness gauge 140, processing feed mechanisms 170 and 270, and a control unit 190.

[0056] The chuck table 10 has a configuration similar to that of the chuck table 10 of the grinding apparatus 1 shown in FIG. 1 and is configured to be rotatable around the central axis of the chuck table 10 by a rotation mechanism (not shown). Furthermore, the chuck table 10 moves as the turntable 110 rotates. The turntable 110 is a disk-shaped table provided on the upper surface of the base 104 of the grinding apparatus 3. Three chuck tables 10 are arranged on the turntable 110 at equal intervals of 120 degrees. When the turntable 110 rotates and the chuck table 10 is located at a transfer position closest to the transfer mechanisms (first transfer mechanism 123, second transfer mechanism 124), the wafer W is transferred in and out at that transfer position. As the turntable 110 rotates, the chuck table 10 moves in the following order: transfer position, rough grinding position, finish grinding position, and transfer position. The rough grinding position and the finish grinding position are positions below the rough grinding mechanism 160 in the first processing chamber 131 and below the finish grinding mechanism 260 in the second processing chamber 132, respectively.

[0057] The contact thickness measuring device 140 is equipped with two height gauges 141 and two height gauges 142. One of the two pairs of height gauges 141 and 142 included in the contact thickness measuring device 140 measures the thickness of the wafer W held on the chuck table 10 located at the rough grinding position in the first processing chamber 131, and the other measures the thickness of the wafer W held on the chuck table 10 located at the finish grinding position in the second processing chamber 132. The height gauge 141 is a contact-type height gauge that measures the height of the upper surface of the frame 12, and the height gauge 142 is a contact-type height gauge that measures the height of the upper surface Wa of the wafer W. The contact thickness measuring device 140 measures the thickness of the wafer W based on the measurement results of the height gauges 141 and 142. For example, the contact thickness measuring device 140 may calculate the thickness of the wafer W by subtracting the thickness of the tape from the difference between the measurement result of the height gauge 141 and the measurement result of the height gauge 142 .

[0058] The non-contact thickness gauge 150 and the non-contact thickness gauge 250 are measuring instruments having a configuration similar to that of the non-contact thickness gauge 50 of the grinding apparatus 1, and are disposed in the first processing chamber 131 and the second processing chamber 132, respectively. That is, the non-contact thickness gauge 150 and the non-contact thickness gauge 250 each have a head unit 151 and a head unit 251 serving as a water layer forming unit, and a motor 152 and a motor 252 serving as a radial movement mechanism, and measure the thickness of the wafer W while forming a water layer between the underside of the non-contact thickness gauge 150 and the upper surface Wa of the wafer W held on the chuck table 10 using water supplied from a water supply source (not shown). Furthermore, the head unit 151 and the head unit 251 serving as the water layer forming unit of the non-contact thickness gauge 150 and the non-contact thickness gauge 250 are also used as cleaning water nozzles for cleaning the upper surface Wa of the wafer W, similar to the water layer forming unit of the non-contact thickness gauge 50 of the grinding apparatus 1. The head portion 151, which is the water layer forming portion of the non-contact thickness measuring device 150, is used as a cleaning water nozzle for cleaning the upper surface Wa of the wafer W in the first processing chamber 131 (rough grinding chamber) after the rough grinding process, and the head portion 251, which is the water layer forming portion of the non-contact thickness measuring device 250, is used as a cleaning water nozzle for cleaning the upper surface Wa of the wafer W in the second processing chamber 132 (finish grinding chamber) before the finish grinding process.

[0059] The rough grinding mechanism 160 and the finish grinding mechanism 260 have the same configuration as the grinding mechanism 60 of the grinding device 1, and are controlled to move up and down by a processing feed mechanism 170 provided on the column 105 and a processing feed mechanism 270 provided on the column 205. The rough grinding mechanism 160 (finish grinding mechanism 260) includes a spindle unit 161 (spindle unit 261), a mount 162 (mount 262), a holder 163 (holder 263), and a grinding wheel 164 (grinding wheel 264). The processing feed mechanism 170 (processing feed mechanism 270) includes a ball screw 171 (ball screw 271), a guide rail 172 (guide rail 272), a motor 173 (motor 273), and a Z-axis stage 174 (Z-axis stage 274).

[0060] The grinding wheel 164 of the rough grinding mechanism 160 is provided with a wheel base 165 and a plurality of rough grinding stones 166. In contrast, the grinding wheel 264 of the finish grinding mechanism 260 is provided with a wheel base 265 and a plurality of finish grinding stones 266. The rough grinding stone 166 and the finish grinding stone 266 differ in that the abrasive grain size of the finish grinding stone 266 is smaller than the abrasive grain size of the rough grinding stone 166.

[0061] The processing chamber cover 130 is a cover that covers the processing chamber consisting of a first processing chamber 131 and a second processing chamber 132. The first processing chamber 131 is the space within the processing chamber partitioned by the processing chamber cover 130 where rough grinding is performed, and a through-hole is formed in the upper surface of the first processing chamber 131 for passing a spindle unit 161 of the rough grinding mechanism 160. The second processing chamber 132 is the space within the processing chamber partitioned by the processing chamber cover 130 where finish grinding is performed, and a through-hole is formed in the upper surface of the second processing chamber 132 for passing a spindle unit 261 of the finish grinding mechanism 260. The first processing chamber 131 and the second processing chamber 132 are separated by a partition wall (not shown) that hangs down from the upper surface of the processing chamber cover 130. In addition, gaps are formed below some of the side surfaces and the partition wall of the processing chamber cover 130 so as not to interfere with the rotation of the turntable 110.

[0062] The cassette 101 and the cassette 102 have the same configuration and contain wafers W before and after grinding, respectively. The robot hand 121 transports the wafers W between the cassette 101 and the positioning mechanism 122 and between the cassette 102 and the spinner cleaning device 125. The positioning mechanism 122 positions the center of the wafer W at the center of the positioning mechanism 122 using a plurality of positioning pins that can advance and retreat relative to the center of the positioning mechanism 122. The first transport mechanism 123 transports the wafer W from the positioning mechanism 122 to the chuck table 10, and the second transport mechanism 124 transports the wafer W from the chuck table 10 to the spinner cleaning device 125. The spinner cleaning device 125 cleans the wafers W after finish grinding. The spinner cleaning device 125 has a spinner table that rotates at high speed and cleans the wafers W by supplying a cleaning liquid to the wafers W held by the spinner table.

[0063] The control unit 190 includes a processor 191 and a memory 192. Various parameters, programs, etc. are stored in the memory 192, and the processor 191 executes the programs stored in the memory 192 to control the operation of each part of the grinding device 3. For example, by the processor 191 executing the programs, in the grinding device 3, in a series of processes for continuously processing a plurality of wafers, a cleaning process is performed before a finish grinding process, and then the finish grinding process is performed.

[0064] In the grinding apparatus 3 configured as described above, the upper surface Wa of the wafer W is cleaned before finish grinding, thereby preventing the start of finish grinding with remaining grinding debris generated during rough grinding on the upper surface Wa of the wafer W. This makes it possible to suppress defects on the upper surface Wa of the wafer W after finish grinding, achieving the same effects as the grinding apparatus 1. Furthermore, the grinding apparatus 3 cleans the upper surface Wa of the wafer W before finish grinding by utilizing the components of an existing grinding apparatus (in this example, the non-contact thickness gauge 150 and the non-contact thickness gauge 250). Therefore, simply by modifying the control program of the existing grinding apparatus, the upper surface Wa of the wafer W can be cleaned before finish grinding, and similar to the grinding apparatus 1, this can be easily applied to existing grinding apparatuses. Furthermore, similar to the grinding device 1, by adjusting the position of the head unit 151 (head unit 251) with the motor 152 (motor 252), water can be supplied near the center of the upper surface Wa of the wafer W, and the entire upper surface Wa of the wafer W can be uniformly and efficiently cleaned by centrifugal force.

[0065] The upper surface Wa of the wafer W may be cleaned while the head unit 151 (head unit 251) is moved in the radial direction of the upper surface Wa of the wafer W by the motor 152 (motor 252).

[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, a circular chuck table 10 is exemplified, but the shape of the chuck table 10 is not limited to circular and may be, for example, rectangular. Even if the shape of the chuck table 10 is other than circular, the same effect can be obtained by cleaning the table before grinding. Note that, when the chuck table 10 is other than circular, the moving mechanism for moving the water layer forming unit does not need to move the water layer forming unit in the radial direction of the chuck table 10, as long as it moves the water layer forming unit between a position above the wafer W and another position.

[0068] In the above-described embodiment, an example was shown in which the top surface of the wafer W is cleaned after rough grinding and before finish grinding in the grinding apparatus 3, but cleaning of the top surface of the wafer W may be performed in at least one of the two processes. This cleaning prevents deep scratches from being caused in the finish grinding process, thereby making it possible to obtain a wafer W with a well-ground top surface Wa. That is, the grinding apparatus 3 may have at least one of the non-contact thickness gauge 150 and the non-contact thickness gauge 250, and at least one of the head unit 151 and the head unit 251 may be used as a cleaning water nozzle.

[0069] In the above-described embodiment, the grinding apparatus 3 uses the non-contact thickness gauges 150 and 250 to clean the wafer before finish grinding. However, even in a two-axis grinding apparatus such as the grinding apparatus 3, if the non-contact thickness gauges 150 and 250 are not provided, a grinding water nozzle, such as the grinding water nozzle 80 for supplying grinding water to the grinding apparatus 2 shown in FIG. 5, may be provided near the chuck table 10. When the grinding water nozzle is provided near the chuck table 10, the grinding water nozzle may be used as a cleaning water nozzle to clean the top surface of the wafer before finish grinding. Because the grinding water nozzle is configured to supply grinding water near the processing point in advance, a radial movement mechanism, as with the non-contact thickness gauge, is not required. The grinding water nozzle is preferably positioned so that the grinding water lands at the center of the wafer.

[0070] In the above-described embodiment, the upper surface of the wafer is cleaned after rough grinding and before finish grinding, but the upper surface of the wafer may be cleaned before rough grinding. Alternatively, the upper surface of the wafer may be cleaned before rough grinding, and then the upper surface of the wafer may be cleaned after rough grinding and before finish grinding. [Industrial Applicability]

[0071] As described above, the grinding apparatus of the present invention can suppress defects on the upper surface of a wafer, and is therefore useful as a grinding apparatus used in, for example, semiconductor manufacturing equipment. [Explanation of symbols]

[0072] 1, 2, 3: grinding device, 4, 104: base, 5, 105, 205: column, 6: waterproof cover, 10: chuck table, 11: porous plate, 12: frame, 15: table rotation mechanism, 20: movement mechanism, 21, 71, 171, 271: ball screw, 22, 72, 172, 272: guide rail, 23, 52, 73, 152, 173, 252, 273: motor, 24: slide part, 30, 130: machining chamber cover, 31: machining Workshop, 40, 140: Contact thickness measuring device, 41, 42, 141, 142: Height gauge, 50, 150: Non-contact thickness measuring device, 51, 151, 251: Head unit, 53: Water supply source, 54: Air supply source, 60: Grinding mechanism, 61, 161, 261: Spindle unit, 62, 162, 262: Mount, 63, 163, 263: Holder, 64, 164, 264: Grinding wheel, 65, 165, 265: Wheel base, 66: Grinding wheel, 70, 170, 270: processing feed mechanism, 74, 174, 274: Z-axis stage, 80: grinding water nozzle, 90, 190: control unit, 91, 191: processor, 92, 192: memory, 101, 102: cassette, 110: turntable, 111: holding surface, 121: robot hand, 122: positioning mechanism, 123: first conveying mechanism, 124: second conveying mechanism, 125: spinner cleaning device, 131: first processing chamber, 132: second processing chamber, 160: rough grinding mechanism, 166: rough grinding wheel, 260: finish grinding mechanism, 266: finish grinding wheel, 510: measurement unit, 511, 521: housing, 512: light emitting unit, 513: half mirror, 514: light receiving unit, 520: photometric protection unit, 522: supply port, 523: opening, 524, Wb: bottom surface, 525: water reservoir, 526: air supply port, 530: cover glass, L: water layer, T: tape, W: wafer, Wa: top surface

Claims

1. A grinding apparatus comprising: a chuck table for holding a wafer; a grinding mechanism for grinding the wafer with a grinding wheel; and a grinding chamber for accommodating the chuck table and the grinding wheel, The grinding apparatus includes a cleaning water nozzle that supplies cleaning water to the upper surface of the wafer held on the chuck table in the grinding chamber before grinding to clean the upper surface.

2. 2. The grinding device according to claim 1, wherein air is mixed into the cleaning water supplied by said cleaning water nozzle.

3. a non-contact thickness measuring device that is disposed in the grinding chamber and that measures the thickness of the wafer held on the chuck table in a non-contact manner; The non-contact thickness measuring device comprises: a water layer forming unit disposed above the wafer, which forms a water layer between the lower surface and the upper surface of the wafer to fill the gap with water; a radial movement mechanism that moves the water layer forming unit in a radial direction of the holding surface of the chuck table, 3. The grinding apparatus according to claim 1, wherein the water layer forming portion is used as the cleaning water nozzle.

4. A grinding device comprising: a chuck table for holding a wafer; a turntable having three or more chuck tables and rotating the turntable about a central axis; a rough grinding mechanism for grinding the wafer with a rough grinding wheel; a finish grinding mechanism for grinding the wafer, which has been rough ground with the rough grinding wheel, with a finish grinding wheel; a rough grinding chamber for accommodating the chuck table and the rough grinding wheel; and a finish grinding chamber for accommodating the chuck table and the finish grinding wheel, a cleaning water nozzle is provided in at least one of the rough grinding chamber and the finish grinding chamber for supplying cleaning water to an upper surface of the wafer to clean the upper surface of the wafer before the wafer held on the chuck table is ground by the finish grinding wheel; Grinding equipment.

5. 5. The grinding device according to claim 4, wherein the cleaning water nozzle includes an air mixing unit for mixing air into the cleaning water.

6. a non-contact thickness measuring device disposed in at least one of the rough grinding chamber and the finish grinding chamber for measuring the thickness of the wafer held on the chuck table in a non-contact manner; The non-contact thickness measuring device comprises: a water layer forming unit disposed above the wafer, which forms a water layer between the lower surface and the upper surface of the wafer to fill the gap with water; a radial movement mechanism that moves the water layer forming unit in a radial direction of the holding surface of the chuck table, 6. The grinding apparatus according to claim 4, wherein the water layer forming portion is used as the cleaning water nozzle.

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