Grinding equipment

Abstract

[Research To] To discharge grinding chips from the holding surface and the porous component constituting the holding surface without increasing the size of the device. [Solution] By allowing the dual fluid 200 to flow from below the porous member 21 toward the retaining surface 22 while the wafer 100 covers the retaining surface 22, grinding chips entering the porous member 21 from the retaining surface 22 can be discharged from the porous member 21 and the retaining surface 22. Furthermore, to discharge grinding chips from the porous member 21, the workpiece, i.e., the wafer 100, and the existing configuration, i.e., the removal mechanism 172, are used. Therefore, since fewer additional components are required to discharge grinding chips from the porous member 21 and the retaining surface 22, the size of the grinding apparatus 1 can be avoided while effectively discharging grinding chips.

Description

Technical Field

[0001] This invention relates to a grinding apparatus. Prior Technology

[0002] In a grinding apparatus, a grinding stone grinds a plate-shaped object held by a porous component of a work chuck, and the grinding chips are discharged. Therefore, the holding surface attracts grinding chips from the outer periphery of the plate-shaped object. Furthermore, the attracted grinding chips are drawn to and remain on the outer periphery of the holding surface, reducing the attraction force and thinning the outer periphery of the plate-shaped object.

[0003] To prevent a decrease in the attractive force of such retaining surfaces, periodic self-grinding of the retaining surfaces is performed to remove grinding chips from the outer periphery of the retaining surfaces. However, the grinding chips generated during self-grinding of the retaining surfaces can enter the porous component, and after self-grinding, there may be grinding chips between the lower surface of the plate held by the retaining surfaces and the retaining surfaces. Therefore, the following situations may occur: localized thinning of the plate or cross-shaped cracks may appear on the plate.

[0004] Therefore, in the technology disclosed in Patent Document 1, a cover is provided that covers the area of ​​the retaining surface, and when the cover has covered the retaining surface, a dual fluid of water and air is sprayed from the retaining surface to remove grinding chips from the retaining surface and the porous member constituting the retaining surface. Previous technical documents Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-060922 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] However, in the technology of Patent Document 1, the device becomes larger because it has a cover that covers the retaining surface and a moving mechanism that moves the cover.

[0008] Therefore, the object of the present invention is to grind the plate to a uniform thickness by discharging grinding chips from the holding surface and the porous member constituting the holding surface, thereby suppressing the presence of grinding chips between the holding surface and the lower surface of the plate, without increasing the size of the device. The means to solve the problem

[0009] The grinding apparatus of the present invention (this grinding apparatus) comprises: a work chuck for attracting and holding a plate-shaped object by means of a holding surface of a porous member; a grinding mechanism for grinding the plate-shaped object attracted and held by the holding surface with a grinding stone; a loading mechanism for holding and loading the plate-shaped object into the holding surface; a loading mechanism for holding and loading the plate-shaped object out of the holding surface; and a control unit. The control unit performs the following controls: The plate-like object is attracted and held at the retaining surface; The plate-shaped object held in place by the holding surface is maintained by the removal mechanism or the insertion mechanism; and A two-fluid mixture of water and air is ejected from the retaining surface covered by the plate-like material. The dual fluid ejected from the retaining surface flows outward in the diameter direction of the retaining surface between the retaining surface and the plate, thereby removing grinding chips from the porous member and the retaining surface. The grinding apparatus may also include a lower surface cleaning mechanism, which cleans the lower surface of the plate held by the transfer mechanism or the transfer mechanism. The control unit cleans the lower surface of the plate that has left the holding surface by means of the lower surface cleaning mechanism after the dual fluid is sprayed from the holding surface, and then covers the holding surface with the plate again, and sprays the dual fluid from the holding surface to remove grinding chips from the porous member and the holding surface. Invention Effects

[0010] In this grinding apparatus, with the retaining surface already covered by a plate, a two-fluid flow can be allowed to pass through the porous component, thereby allowing grinding chips that have entered the porous component from the retaining surface to be discharged from both the porous component and the retaining surface. Therefore, since the situation where grinding chips are trapped between the retaining surface and the workpiece during grinding by the grinding mechanism can be suppressed, the workpiece can be ground to a uniform thickness.

[0011] Furthermore, in this grinding apparatus, existing components, namely the conveying mechanism or the conveying mechanism, are used to discharge grinding chips from the porous member and the holding surface. As a result, fewer additional components are required to discharge grinding chips, thus avoiding the need for a large-scale grinding apparatus while ensuring the effective discharge of grinding chips. Simple Explanation of the Diagram

[0012] Figure 1 is a perspective view showing the structure of the grinding apparatus. Figure 2 is an explanatory diagram showing the first holding step and the second holding step. Figure 3 is an explanatory diagram showing the fluid ejection process. Figure 4 is an explanatory diagram showing the cleaning steps for the lower surface. Figure 5 is an explanatory diagram showing a modified example of the pad of the transfer mechanism. Implementation

[0013] Forms used to implement inventions

[0014] As shown in Figure 1, the grinding apparatus 1 of this embodiment is an apparatus for grinding a workpiece, namely a wafer 100. The wafer 100 is, for example, a circular plate-shaped workpiece, and has a front side 101 and a back side 102. The back side 102 of the wafer 100 is the surface to be ground. Furthermore, the wafer 100 also functions as a plate-shaped object used to remove grinding chips from the porous member 21 and the holding surface 22.

[0015] The grinding apparatus 1 has a first apparatus base 10 and a second apparatus base 11 disposed behind the first apparatus base 10 (on the +Y direction side).

[0016] A first wafer cassette stage 160 and a second wafer cassette stage 162 are provided on the -Y direction side of the first device base 10. The first wafer cassette stage 160 holds a first wafer cassette 161 for accommodating a wafer 100 before processing. The second wafer cassette stage 162 holds a second wafer cassette 163 for accommodating a wafer 100 after processing.

[0017] The first wafer cassette 161 and the second wafer cassette 163 have a plurality of shelves inside, and each shelf holds wafers 100 one by one. That is, the first wafer cassette 161 and the second wafer cassette 163 hold a plurality of wafers 100 in a shelf-like manner.

[0018] The openings (not shown) of the first wafer cassette 161 and the second wafer cassette 163 face the +Y direction. A robot 155 is disposed on the +Y direction side of these openings. The robot 155 has a holding surface for holding the wafer 100. The robot 155 moves (stores) the processed wafer 100 into the second wafer cassette 163. Furthermore, the robot 155 removes the unprocessed wafer 100 from the first wafer cassette 161 and places it on the temporary worktable 154 of the temporary holding mechanism 152.

[0019] The temporary placement mechanism 152 is used to temporarily place the wafer 100 removed from the first cassette 161 and is positioned adjacent to the robot 155. The temporary placement mechanism 152 includes a temporary placement stage 154 and an alignment member 153. The alignment member 153 includes a plurality of alignment pins arranged externally to surround the temporary placement stage 154; and a slider to move the alignment pins in the radial direction of the temporary placement stage 154. In the alignment member 153, the diameter of the circle connecting the plurality of alignment pins is reduced by moving the alignment pins toward the center in the radial direction of the temporary placement stage 154. This allows the wafer 100, already placed on the temporary placement stage 154, to be aligned (centered) to a predetermined position where the center of the temporary placement stage 154 coincides with the center of the wafer 100.

[0020] An infeed mechanism 170 is provided adjacent to the temporary mechanism 152. The infeed mechanism 170 holds the wafer 100 that has been temporarily placed in the temporary mechanism 152 and moves it into the holding surface 22 of the work chuck 20 for placement.

[0021] The work chuck 20 is one example of a holding member for holding the wafer 100, and has a holding surface 22 for attracting and holding the wafer 100. The holding surface 22 is connected to the attraction source 47 (see Figure 2) and can attract and hold the wafer 100. The work chuck 20 can rotate with a central axis extending in the Z-axis direction through the center of the holding surface 22 as the center, while the wafer 100 is being attracted and held by the holding surface 22.

[0022] In this embodiment, two worktables 20 are arranged on the upper surface of the turntable 6, which is mounted on the second device base 11, on a circle centered on the center of the turntable 6. A rotation axis (not shown) for rotating the turntable 6 is arranged at the center of the turntable 6. The turntable 6 can rotate around an axis extending in the Z-axis direction via this rotation axis. As the turntable 6 rotates, the two worktables 20 revolve around it. This allows the worktables 20 to be positioned near the temporary holding mechanism 152 and below the grinding mechanism 70.

[0023] Furthermore, a support column 15 is erected on the +Y direction side of the second device base 11. A grinding mechanism 70 for grinding the wafer 100 and a grinding feed mechanism 60 are provided on the front surface of the support column 15.

[0024] The grinding feed mechanism 60 moves the worktable 20 and the grinding stone 77 of the grinding mechanism 70 relative to each other in the Z-axis direction (grinding feed direction) perpendicular to the holding surface 22. In this embodiment, the grinding feed mechanism 60 is configured to move the grinding stone 77 relative to the worktable 20 in the Z-axis direction.

[0025] The grinding feed mechanism 60 includes: a pair of Z-axis guideways 61 parallel to the Z-axis direction, a Z-axis moving table 63 sliding on the Z-axis guideways 61, a Z-axis ball screw 62 parallel to the Z-axis guideways 61, a Z-axis motor 64, and a support 66 mounted on the Z-axis moving table 63. The support 66 supports the grinding mechanism 70.

[0026] The Z-axis moving table 63 is configured to slide on the Z-axis guide rail 61. A nut (not shown) is fixed to the Z-axis moving table 63. A Z-axis ball screw 62 is screwed into this nut. The Z-axis motor 64 is connected to one end of the Z-axis ball screw 62.

[0027] In the grinding feed mechanism 60, the Z-axis ball screw 62 is rotated by the Z-axis motor 64, causing the Z-axis moving table 63 to move along the Z-axis guide rail 61 in the Z-axis direction. Consequently, the support 66 mounted on the Z-axis moving table 63 and the grinding mechanism 70 supported on the support 66 also move together with the Z-axis moving table 63 in the Z-axis direction.

[0028] The grinding mechanism 70 grinds the wafer 100 held by the holding surface 22 of the work chuck 20 using a grinding stone 77. The grinding mechanism 70 includes: a spindle housing 71 fixed to the support 66, a spindle 72 rotatably held in the spindle housing 71, a spindle motor 73 that drives the spindle 72, a wheel seat 74 mounted on the lower end of the spindle 72, and a grinding wheel 75 supported by the wheel seat 74.

[0029] The spindle housing 71 is held in the support 66 in a manner that extends in the Z-axis direction. The spindle 72 extends in the Z-axis direction orthogonal to the holding surface 22 of the worktable 20 and is rotatably supported by the spindle housing 71.

[0030] The spindle motor 73 is connected to the upper end of the spindle 72. The spindle 72 rotates around a rotation axis extending in the Z-axis direction via the spindle motor 73.

[0031] The wheel holder 74 is formed in the shape of a circular plate and is fixed to the lower end (front end) of the spindle 72. The wheel holder 74 supports the grinding wheel 75.

[0032] The grinding wheel 75 is formed with an outer diameter that is approximately the same as the outer diameter of the wheel base 74. The grinding wheel 75 includes an annular wheel base 76 formed of metal. On the lower surface of the wheel base 76, a plurality of grinding stones 77 arranged in a ring are fixed around the entire circumference. The grinding stones 77 rotate together with the spindle motor 73 and the spindle 72 with their center as the axis, and grind the back surface 102 of the wafer 100 held in the work chuck 20.

[0033] The ground wafer 100 can be removed by the removal mechanism 172. The removal mechanism 172 holds the wafer 100, which is held on the holding surface 22 of the work chuck 20, and removes it from the holding surface 22. The removal mechanism 172 transports the wafer 100, which has been removed from the holding surface 22, to the rotary table 157 of the monolithic rotary cleaning mechanism 156. Furthermore, the configuration of the removal mechanism 172 will be described later.

[0034] The rotary cleaning mechanism 156 is a rotary cleaning unit for cleaning the wafer 100. The rotary cleaning mechanism 156 includes a rotary table 157 for holding the wafer 100 and nozzles 158 for spraying cleaning water and dry air toward the rotary table 157.

[0035] In the rotary cleaning mechanism 156, the rotary table 157 holding the wafer 100 rotates and sprays cleaning water toward the wafer 100 to clean it by rotation. Afterward, dry air is sprayed onto the wafer 100 to dry it.

[0036] The wafer 100 that has been cleaned by the rotary cleaning mechanism 156 can be moved into the second wafer cassette 163 on the second wafer cassette stage 162 by the robot 155.

[0037] Furthermore, a lower surface cleaning mechanism 180 is provided between the turntable 6 and the rotary cleaning mechanism 156. The lower surface cleaning mechanism 180 is used to clean the lower surface, i.e., the front surface 101, of the wafer 100 that is transported from the work chuck 20 to the rotary cleaning mechanism 156 by the transfer mechanism 172. That is, the lower surface cleaning mechanism 180 cleans the front surface 101 of the wafer 100 held by the transfer mechanism 172.

[0038] Here, we will explain the configuration of the worktable 20. As shown in Figure 2, the work chuck 20 is a circular plate-shaped worktable used to hold the wafer 100. The work chuck 20 includes a circular plate-shaped porous component 21 and a frame 23 supporting the porous component 21. The porous component 21 is connected to the attraction source 47. The work chuck 20 can attract and hold the wafer 100 by means of the attraction force from the attraction source 47 being transmitted to the upper surface, i.e., the holding surface 22, of the porous component 21.

[0039] Furthermore, the worktable 20 is configured to be rotatable by a rotating mechanism 30. The rotating mechanism 30 may be, for example, a pulley mechanism, and includes a motor 31 that serves as a drive source, a drive pulley 32 mounted on the shaft of the motor 31, a driven pulley 34 connected to the drive pulley 32 via an endless belt 33, and a rotating shaft 35 supporting the driven pulley 34.

[0040] The rotating shaft 35 is located directly below the center of the retaining surface 22 on the lower surface of the work chuck 20, and extends perpendicularly to the retaining surface 22 of the work chuck 20. The driving pulley 32 is driven by the rotation of the motor 31, and the endless belt 33 rotates in tandem with the rotation of the driving pulley 32. The driven pulley 34 and the rotating shaft 35 rotate due to the rotation of the endless belt 33. Thus, the work chuck 20 rotates about the center of the retaining surface 22 as its axis.

[0041] Furthermore, the grinding apparatus 1 is equipped with a fluid flow mechanism 40. The fluid flow mechanism 40 is a mechanism for supplying fluid, i.e., air or water, to the holding surface 22 of the worktable 20, or for applying an attractive force to the holding surface 22.

[0042] The fluid flow mechanism 40 includes a suction groove 403, a suction flow path 470 connected to the suction groove 403, a rotary joint 460 connected to the rotating shaft 35, and a suction pipe 471 connected to the suction flow path 470.

[0043] The suction groove 403 is provided on the bottom surface of the recess of the frame 23 in the work clamp 20 in a manner that connects with the lower surface of the porous component 21. The suction groove 403 is formed in a concentric circle with the center of the work clamp 20 as the center.

[0044] The suction flow path 470 extends from the bottom surface of the suction groove 403 by passing through the frame 23, the rotating shaft 35 and the rotary joint 460.

[0045] The suction flow path 470 is connected to the suction pipe 471 outside the rotary joint 460. One end of the suction pipe 471 is connected to the suction flow path 470. The other end of the suction pipe 471 is connected to the suction source 47. This suction source 47 is, for example, equipped with an ejector mechanism or a vacuum generating device, and is used to apply suction to the upper surface, i.e., the holding surface 22, of the porous member 21 connected to the work clamp 20.

[0046] Furthermore, in the suction pipe 471, a suction switching valve 475 and a suction flow adjustment unit 473 are sequentially arranged from the suction source 47 toward the suction flow path 470. The suction switching valve 475 switches the connection state between the suction pipe 471 and the suction source 47. The suction flow adjustment unit 473 is, for example, a proportional control valve, and is used to change the internal orifice diameter when the suction switching valve 475 is open, thereby adjusting the suction force transmitted from the suction source 47 to the holding surface 22 of the porous member 21. Furthermore, the suction flow adjustment unit 473 can also be a needle valve or gate valve for manually adjusting the orifice diameter.

[0047] In addition, an air pipe 481 is connected to the suction pipe 471. The air pipe 481 is used to connect the holding surface 22 of the work stand 20 to the air supply source 48.

[0048] One end of the air pipe 481 is connected to the suction flow path 470 via the suction pipe 471. The other end of the air pipe 481 is connected to an air supply source 48. The air supply source 48 includes a compressor and is used to supply air to the holding surface 22 of the worktable 20.

[0049] Furthermore, in the air piping 481, an air supply switching valve 485 and an air regulating unit 483 are sequentially arranged from the air supply source 48 toward the suction flow path 470. The air supply switching valve 485 switches the connection state between the air piping 481 and the air supply source 48. The air regulating unit 483 is, for example, a proportional control valve, and is used to adjust the flow rate of air delivered from the air supply source 48 to the holding surface 22 by changing the diameter of its internal orifice when the air supply switching valve 485 is open. Furthermore, the air adjustment unit 483 can also be a needle valve or gate valve whose orifice diameter can be adjusted manually.

[0050] Furthermore, a pressure sensor 487 is installed on the air pipe 481. The pressure sensor 487 detects the attraction force of the retaining surface 22 by detecting the pressure value of the air pipe 481.

[0051] Furthermore, a water pipe 491 is connected to the air pipe 481. The water pipe 491 is used to connect the holding surface 22 of the work clamp 20 to the water supply source 49.

[0052] One end of the water pipe 491 is connected to the suction flow path 470 via the air pipe 481 and the suction pipe 471. The other end of the water pipe 491 is connected to a water supply source 49. The water supply source 49 is equipped with a pump and is used to supply water to the holding surface 22 of the work clamp 20.

[0053] Furthermore, in the water piping 491, a water supply switch valve 495 and a water adjustment unit 493 are sequentially arranged from the water supply source 49 toward the suction flow path 470. The water supply switch valve 495 switches the connection state between the water piping 491 and the water supply source 49. The water adjustment unit 493 is, for example, a proportional control valve, and is used to adjust the flow rate of water delivered from the water supply source 49 to the holding surface 22 by changing the diameter of its internal orifice when the water supply switch valve 495 is open. Furthermore, the water adjustment unit 493 can also be a needle valve or gate valve for manually adjusting the orifice diameter.

[0054] Next, the configuration of the loading mechanism 170 and the unloading mechanism 172 will be explained. Furthermore, in this embodiment, the loading mechanism 170 and the unloading mechanism 172 have the same configuration. Therefore, the configuration of the unloading mechanism 172 will be explained below.

[0055] As shown in Figure 2, the transfer mechanism 172 includes a circular plate-shaped pad 80 and an arm 81 that suspends and supports the pad 80 freely up and down. One end of the arm 81 is connected to the upper end of a rotating column 82 that extends from the first device base 10 (see Figure 1) in the Z-axis direction. Furthermore, the rotating column 82 is connected to a motor 94 that rotates the rotating column 82 and the arm 81 together, and to a vertical movement mechanism 95 that moves the rotating column 82 and the arm 81 together in the vertical direction.

[0056] At the other end of the arm 81, a circular plate member 84 is connected via a support post 83. A plurality of (e.g., 3) through holes 85 are formed in the circular plate member 84 at equal intervals on the circumference. Bolts 86, which are already connected to pads 80, are inserted into the through holes 85.

[0057] The bolt 86 has a shaft portion 87 and a head 88. The shaft portion 87 has a diameter slightly smaller than that of the through hole 85, and the head 88 is formed at the upper end of the shaft portion 87. The shaft portion 87 passes through the through hole 85 and is loosely fitted. The lower end of the shaft portion 87 is connected to the upper surface of the frame 91 of the pad 80. The head 88 is formed with a diameter larger than the through hole 85, thereby limiting the range of descent of the bolt 86. Furthermore, bolt 86 has a spring 860 around shaft portion 87 as an impact absorbing member. The upper end of spring 860 contacts the lower surface of circular plate member 84, while the lower end of spring 860 contacts the upper surface of frame 91 of pad 80. Spring 860 imparts potential energy to circular plate member 84 and pad 80 in a direction away from each other.

[0058] The arm 81 is configured to absorb the impact applied to the pad 80 while suspending and supporting the pad 80 through the circular plate member 84 and the bolt 86.

[0059] The disc-shaped pad 80 includes, for example, a pad holding portion 90 and a frame 91. The pad holding portion 90 has an area slightly larger than that of the wafer 100 and is made of a porous material. The frame 91 supports the pad holding portion 90. The lower surface of the pad holding portion 90 becomes the pad holding surface 92 that attracts and holds the upper surface, i.e., the back surface 102, of the wafer 100.

[0060] Furthermore, the removal mechanism 172 includes a suction path 89. The suction path 89 extends into a frame 91 that passes through the arm 81, the support column 83, the circular plate member 84, and the pad 80, and its lower end is connected to the upper surface of the pad holding portion 90. Furthermore, the upper end of the suction path 89 is connected to the suction source 99.

[0061] Thus, in the removal mechanism 172, when the pad holding surface 92 is in contact with the wafer 100 held on the holding surface 22 of the work chuck 20, by connecting the attraction source 99 to the attraction path 89, the attraction force of the attraction source 99 can be transmitted to the pad holding surface 92, and the wafer 100 is attracted and held by the pad holding surface 92.

[0062] Furthermore, the rotating column 82 and the arm 81 can be rotated and raised and lowered by the motor 94 and the up-and-down moving mechanism 95, thereby causing the pad 80 holding the wafer 100 to rotate and rise and fall, and the wafer 100 to be removed from the work chuck 20.

[0063] Furthermore, as shown in Figure 1, the grinding apparatus 1 has a control unit 7 for controlling the grinding apparatus 1. The control unit 7 includes a CPU for performing calculations according to a control program, and memory media such as memory. The control unit 7 performs various processes and integrates the control of the various components of the grinding apparatus 1.

[0064] For example, the control unit 7 controls the aforementioned components of the grinding device 1 to perform grinding processing on the wafer 100.

[0065] Furthermore, in order to prevent the decrease in the attractive force of the surface of the porous member 21 in the work chuck 20, i.e. the holding surface 22, the control unit 7 periodically performs self-grinding of the holding surface 22 by grinding with the grinding stone 77 of the grinding mechanism 70 to remove grinding chips from the outer periphery of the holding surface 22. Furthermore, when grinding the retaining surface 22, it is acceptable whether or not fluid is ejected from the retaining surface 22.

[0066] Furthermore, during this self-grinding process, grinding chips may enter the interior of the porous component 21. These grinding chips include: debris generated from grinding the porous component 21 due to the grinding of the holding surface 22, grinding chips generated when grinding the wafer 100 remaining on the outer periphery of the holding surface 22, and abrasive grains that fall off from the grinding stone 77 grinding the holding surface 22. Therefore, the control unit 7 performs a cleaning process to remove the grinding chips from the porous component 21 and the holding surface 22. The cleaning process in this embodiment will be explained below.

[0067] [Step 1] In the cleaning process, the control unit 7 first uses the robot 155 to take out the wafer 100 before processing from the first wafer cassette 161 and place it on the temporary worktable 154 of the temporary mechanism 152, and position the wafer 100 in the predetermined position.

[0068] Furthermore, the control unit 7 controls the loading mechanism 170 to hold the wafer 100 on the temporary holding mechanism 152. That is, the control unit 7 uses the motor 94 and the up-and-down movement mechanism 95 of the loading mechanism 170 shown in FIG. 2 to rotate and raise the pad 80, so that the pad holding surface 92 contacts the wafer 100 on the temporary holding mechanism 152. In this state, by connecting the attraction source 99 to the attraction path 89, the loading mechanism 170 attracts and holds the wafer 100 by means of the pad holding surface 92 of the pad 80.

[0069] Subsequently, the control unit 7 places the wafer 100 onto the holding surface 22 of the work chuck 20, which is located near the temporary holding mechanism 152, by rotating and raising the pad 80 of the loading mechanism 170, and retracts the pad 80 from the work chuck 20. Thus, as shown in FIG2, the holding surface 22 is covered by the wafer 100.

[0070] Subsequently, the control unit 7 opens the suction switch valve 475 shown in FIG. 2 and adjusts the orifice diameter of the suction flow adjustment unit 473, thereby connecting the porous component 21 of the work chuck 20 to the suction source 47. Thereby, the holding surface 22 of the work chuck 20 attracts and holds the wafer 100. Furthermore, the orifice diameter of the suction flow adjustment unit 473 can also be fully open.

[0071] [Second Holding Step] Secondly, the control unit 7 uses the transfer mechanism 172 to hold the wafer 100 held by the holding surface 22. That is, the control unit 7 uses the motor 94 and the up-and-down movement mechanism 95 of the transfer mechanism 172 to rotate and raise the pad 80, so that the pad holding surface 92 contacts the wafer 100 held by the holding surface 22 of the work chuck 20. In this state, by connecting the attraction source 99 to the attraction path 89, the transfer mechanism 172 can attract and hold the wafer 100 by the pad holding surface 92 of the pad 80.

[0072] Thus, as shown in Figure 2, the wafer 100 is held by the unloading mechanism 172 with the holding surface 22 of the work chuck 20 covered. Afterwards, the control unit 7 stops the suction and holding of the wafer 100 by the holding surface 22 of the work chuck 20 by closing the suction switch valve 475.

[0073] [Fluid ejection procedure] Next, the control unit 7 sprays a mixed fluid of water and air, i.e., a dual fluid, from the holding surface 22 covered by the wafer 100. In this way, the dual fluid sprayed from the holding surface 22 flows outward in the diameter direction of the holding surface 22 between the holding surface 22 and the wafer 100, and removes grinding chips from the porous member 21 of the work chuck 20 and the holding surface 22.

[0074] That is, the control unit 7 opens the air supply switch valve 485 and the water supply switch valve 495, and adjusts the orifice diameter of the air adjustment unit 483 and the orifice diameter of the water adjustment unit 493, so that the porous component 21 of the work stand 20 is connected to the air supply source 48 and the water supply source 49. In this way, the control unit 7 supplies a predetermined amount of air and water to the porous component 21 as shown by arrow 501 in FIG3. Furthermore, the orifice diameters of the air adjustment unit 483 and the water adjustment unit 493 can also be fully open.

[0075] The dual fluid supplied to the porous member 21 flows upward within the porous member 21 and is ejected outward from the holding surface 22 along with the grinding chips within the porous member 21. As shown in FIG3, the wafer 100 held in the unloading mechanism 172, with the holding surface 22 covered, floats off the holding surface 22 along with the pad 80 due to the resistance of the dual fluid 200, as indicated by arrow 503, to the potential exerted by the spring 860. Furthermore, the dual fluid 200 containing grinding chips flows out radially outward from the gap between the holding surface 22 and the wafer 100. Furthermore, as shown in Figure 3, the spring 860 will contract as the pad 80 rises, and the head 88 of the bolt 86 will float off the upper surface of the circular plate component 84.

[0076] After a predetermined time has elapsed since the ejection of the dual fluid 200, the control unit 7 closes the air supply switch valve 485 and the water supply switch valve 495, thereby stopping the ejection of the dual fluid 200. Then, the control unit 7 causes the wafer 100 to leave the holding surface 22 by rotating and raising / lowering the pad 80 of the wafer removal mechanism 172.

[0077] As described above, in this embodiment, by allowing the dual fluid 200 to flow from below the porous member 21 toward the retaining surface 22 while the wafer 100 covers the retaining surface 22, grinding chips entering the porous member 21 from the retaining surface 22 are discharged from the porous member 21 and the retaining surface 22. Therefore, since the presence of grinding chips between the retaining surface 22 and the wafer 100 can be suppressed when the wafer 100 is ground by the grinding mechanism 70, the wafer 100 can be ground to a uniform thickness.

[0078] Furthermore, in this embodiment, the workpiece, namely the wafer 100, and the existing component, namely the removal mechanism 172, are used to discharge grinding chips from the porous component 21. As a result, since fewer additional components are required to discharge grinding chips from the porous component 21 and the holding surface 22, the size of the grinding apparatus 1 can be avoided, and the discharge of grinding chips can be achieved.

[0079] Furthermore, during the fluid ejection step, if the dual fluid 200 is supplied to the porous member 21 while the holding surface 22 is not covered by the wafer 100, the dual fluid 200 will only be ejected from the holding surface 22 through the easily passable portion of the porous member 21. Therefore, it is difficult to remove grinding chips from the entire area of ​​the porous member 21.

[0080] In this embodiment, the dual fluid 200 is supplied to the porous member 21 while the wafer 100, held in place by the removal mechanism 172, covers the holding surface 22. This allows the dual fluid 200 to be ejected from the holding surface 22 under pressure, thus enabling it to be ejected from the entire surface of the holding surface 22. Consequently, grinding chips can be discharged from approximately the entire area within the porous member 21.

[0081] Furthermore, after the dual fluid 200 is ejected from the holding surface 22, the control unit 7 can use the lower surface cleaning mechanism 180 shown in FIG1 to clean the lower surface (i.e., the front surface 101) of the wafer 100 that has left the holding surface 22, and then cover the holding surface 22 with the wafer 100 again, and eject the dual fluid 200 from the holding surface 22 to remove grinding chips from the porous member 21 and the holding surface 22.

[0082] In this case, the control unit 7 will perform the following surface cleaning step after the fluid ejection step.

[0083] [Bottom Surface Cleaning Steps] The control unit 7 causes the wafer 100 to leave the holding surface 22 by rotating and raising the pad 80 of the removal mechanism 172 holding the wafer 100, and arranges it directly above the lower surface cleaning mechanism 180 as shown in FIG4.

[0084] The lower surface cleaning mechanism 180 includes a sponge roller 181, a hollow shaft 182, and a base member 183. The shaft 182 is inserted into the sponge roller 181 to hold the sponge roller 181 in place, and the base member 183 supports the shaft 182 so that it can rotate freely. The shaft 182 is connected to a water source 185 through a connector 184, allowing water supplied from the water source 185 to be supplied to the sponge roller 181 through holes provided on the surface of the shaft 182.

[0085] Then, as shown in FIG. 4, the control unit 7 adjusts the position of the pad 80 holding the wafer 100 in the removal mechanism 172 so that the front surface 101 of the wafer 100 comes into contact with the sponge roller 181 in the lower surface cleaning mechanism 180. Furthermore, while supplying water to the sponge roller 181 of the lower surface cleaning mechanism 180, the control unit 7 rotates the pad 80 holding the wafer 100 horizontally relative to the lower surface cleaning mechanism 180 as shown by arrow 505 in FIG. 4. In this way, the water-containing sponge roller 181 rotates and contacts the front surface 101 of the wafer 100, thereby cleaning the front surface 101.

[0086] After the entire front surface 101 of the wafer 100 has been cleaned, the control unit 7 ends the lower surface cleaning step and causes the pad 80 of the transfer mechanism 172 to rotate and rise, thereby covering the holding surface 22 of the work chuck 20 with the wafer 100. Then, the control unit 7 performs the above-mentioned fluid ejection step again to remove grinding chips from the porous member 21 and the holding surface 22.

[0087] In this configuration, the removal of grinding chips from the porous member 21 and the holding surface 22 can be repeatedly performed while cleaning the lower surface (front surface 101) of the wafer 100. Thus, grinding chips can be effectively removed from the porous member 21 and the holding surface 22.

[0088] Furthermore, in the above-described embodiment, as shown in FIG2, the area of ​​the pad 80 in the transfer mechanism 172 is slightly larger than the area of ​​the wafer 100. Alternatively, as shown in FIG5, the pad 80 may have a smaller area than the wafer 100.

[0089] In this configuration, the pad 80 does not hold the outer peripheral portion of the wafer 100. Therefore, during the fluid ejection step, when the dual fluid 200 is ejected from the holding surface 22 of the work chuck 20, it becomes easier to create a gap between the holding surface 22 and the outer peripheral portion of the wafer 100. Consequently, since it becomes easier to discharge the dual fluid 200 containing grinding chips from the gap between the holding surface 22 and the wafer 100 radially outward from the holding surface 22, grinding chips can be effectively removed from the porous member 21 and the holding surface 22.

[0090] Furthermore, in the above embodiment, a wafer 100 is used as a plate-like object covering the holding surface 22 of the work chuck 20 during the fluid ejection step. In this regard, a dummy wafer or a plate-like component can also be used as the plate-like object covering the holding surface 22. The dummy wafer can be, for example, a wafer that is not the object being ground by the grinding apparatus 1. The plate-like component can be, for example, a component used for cleaning the porous component 21. In this case, the dummy wafer or plate-like component is pre-placed in the first wafer cassette 161 and can be removed by the robot 155 during the first holding step and attracted and held on the holding surface 22 of the work chuck 20.

[0091] Furthermore, in the above embodiment, the control unit 7 performs the fluid ejection step while the holding surface 22 of the work chuck 20 is covered by the wafer 100 held by the transfer mechanism 172. Alternatively, the control unit 7 can also perform the fluid ejection step while the wafer 100 held by the transfer mechanism 170 covers the holding surface 22 of the work chuck 20. In this case, during the second holding step, the transfer mechanism 170 holds the wafer 100 that has been attracted and held on the holding surface 22. Also, in this case, the lower surface cleaning mechanism 180 can be positioned near the transfer mechanism 170.

[0092] 1: Grinding equipment 6: Turntable 7: Control Department 10: Base of Device 1 11: Base of the second device 15: Pillar 20: Worktable 21: Porous components 22: Keep the surface 23: Frame 30: Rotating mechanism 31: Motor 32: Drive pulley 33: Endless belt 34: Driven pulley 35: Rotation axis 40: Fluid flow mechanism 47: Source of Attraction 48: Air supply source 49: Water supply source 60: Grinding feed mechanism 61: Z-axis guide rail 62: Z-axis ball screw 63: Z-axis moving table 64: Z-axis motor 66: Supporter 70: Grinding mechanism 71: Spindle housing 72: Spindle 73: Spindle Motor 74: Wheel seat 75: Grinding wheel 76: Wheel base platform 77: Grinding stone 80: Pad 81: Arm 82: Rotating column 83: Pillar 84: Circular plate components 85: Through hole 86: Bolt 87: Shaft 88: Head 89: Attraction Path 90: Pad retaining part 91: Frame 92: Pad retaining surface 94: Motor 95: Up and down moving mechanism 99: Source of Attraction 100: Wafer 101: Front 102: Back 152: Temporary Institution 153: Alignment Components 154: Temporary Workbench 155: Robot 156: Rotary washing mechanism 157: Rotary worktable 158: Nozzle 160: First cartridge carrier platform 161: 1st cassette 162: Second cassette platform 163: 2nd cartridge 170: Moving-in agency 172: Relocation Agency 180: Lower surface cleaning mechanism 181: Sponge Roller 182: Shaft 183: Base components 184: Connector 185: Water Source 200: Two-fluid 403: Attraction Ditch 460: Rotary Joint 470: Attraction Flow Path 471: Suction piping 473: Attraction Flow Adjustment Department 475: Suction switch valve 481: Air piping 483: Air Conditioning Department 485: Air supply switch valve 487: Pressure sensor 491:Water piping 493: Water Adjustment Department 495: Water supply switch valve 501, 503, 505: Arrows 860: Spring +X,-X,+Y,-Y,+Z,-Z: Direction

Claims

1. A grinding apparatus comprising: a work chuck for attracting and holding a plate-shaped object via a holding surface of a porous member; a grinding mechanism for grinding the plate-shaped object attracted and held by the holding surface with a grinding stone; an infeed mechanism for holding the plate-shaped object and infeeding it into the holding surface; an outfeed mechanism for holding the plate-shaped object and outfeeding it from the holding surface; and a control unit, the grinding apparatus further comprising a lower surface cleaning mechanism for cleaning the lower surface of the plate-shaped object held by the outfeed mechanism or the infeed mechanism, the control unit performing the following control: attracting and holding the plate-shaped object on the holding surface; holding the plate-shaped object attracted and held by the holding surface via the outfeed mechanism or the infeed mechanism; and spraying a two-fluid mixture of water and air from the holding surface covered with the plate-shaped object. After the dual fluid is ejected from the holding surface, the lower surface of the plate that has left the holding surface is cleaned by the lower surface cleaning mechanism, and the holding surface is covered again with the plate, and the dual fluid is ejected from the holding surface. The dual fluid ejected from the holding surface flows outward in the diameter direction of the holding surface between the holding surface and the plate, thereby removing grinding chips from the porous member and the holding surface.

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