TWI866999B - Wafer transfer mechanism and grinding device - Google Patents

Abstract

[Topic] Provide a wafer transfer mechanism that can prevent the wafer from being damaged due to grinding chips attached to the wafer. [Solution] A wafer transfer mechanism includes a wafer holding assembly for holding a wafer and a moving assembly for moving the wafer holding assembly. The wafer holding assembly includes a suction holding portion and a water supply portion, the suction holding portion having a porous surface for sucking and holding the outer peripheral area of the wafer, and the water supply portion is arranged on the inner side of the suction holding portion and supplies water.

Description

Wafer transfer mechanism and grinding device

The present invention relates to a wafer transfer mechanism for transferring wafers and a grinding device having the wafer transfer mechanism.

The wafer with multiple devices such as IC, LSI, memory, etc. divided by predetermined dividing lines and formed on the front side is ground by a grinding device to form a predetermined thickness on the back side, and then divided into individual device chips by a cutting device or laser processing device for use in electronic devices such as mobile phones and personal computers.

The grinding device is composed of at least a cassette loading portion, a wafer loading and unloading assembly, a temporary assembly, a first conveying assembly, a grinding assembly and a second conveying assembly, and can appropriately grind wafers. The cassette loading portion is used to load a cassette containing a plurality of wafers. The wafer loading and unloading assembly is used to load and unload wafers from a cassette loaded on the cassette loading portion. The temporary assembly is used to temporarily hold wafers loaded by the wafer loading and unloading assembly. The first conveying assembly is used to transfer the wafer temporarily placed on the temporary assembly to a worktable. The grinding assembly is used to grind the upper surface of the wafer held on the worktable. The second conveying assembly is used to transfer the ground wafer from the worktable to a cleaning assembly (see, for example, Patent Document 1). The first transfer assembly and the second transfer assembly include a suction pad for attracting and holding the wafer. Prior art literature Patent literature

Patent document 1: Japanese Patent Application Publication No. 2005-158854

Invention Problems to be Solved

However, if the back side of the ground wafer is held by the suction pad of the second transfer assembly, there is a problem that the grinding chips attached to the back side of the wafer dry and solidify, and the wafer is damaged in a subsequent step due to the solidified grinding chips.

Furthermore, if the thinned wafer is held by the suction pad of the second transfer assembly, there is a problem that grinding chips are caught between the suction pad and the wafer, thereby damaging the wafer.

The subject of the present invention made in view of the above facts is to provide a wafer transfer mechanism and a grinding device having a wafer transfer mechanism that can prevent the wafer from being damaged due to grinding chips attached to the wafer. Means for solving the problem

The first aspect of the present invention is to provide the following wafer transfer mechanism in order to solve the above-mentioned problem. That is, the first aspect of the present invention is to provide a wafer transfer mechanism for transferring wafers, wherein the wafer transfer mechanism has a wafer holding assembly for holding the wafer and a moving assembly for moving the wafer holding assembly, and the wafer holding assembly includes a suction holding part and a water supply part, wherein the suction holding part has a porous surface for sucking and holding the peripheral area of the wafer, and the water supply part is arranged on the inner side of the suction holding part and supplies water.

Preferably, the suction and holding part is composed of a plurality of segments, and the water supplied from the water supply part flows out between adjacent segments. Preferably, an annular wall is provided around the suction and holding part, and the annular wall is used to suppress the water level of the water flowing out from between the adjacent segments.

The second aspect of the present invention is to provide the following grinding device to solve the above-mentioned problem. That is, a grinding device is composed of at least a cassette loading part, a wafer carrying assembly, a temporary assembly, a first conveying assembly, a grinding assembly and a second conveying assembly. The cassette loading part is used to load a cassette containing a plurality of wafers, the wafer carrying assembly is used to carry wafers out and in from the cassette loaded on the cassette loading part, and the temporary assembly is used to carry wafers by the wafer carrying assembly. The wafer to be moved out is temporarily placed, the first transfer assembly is used to transfer the wafer temporarily placed on the temporary assembly to the work clamp, the grinding assembly is used to grind the upper surface of the wafer held on the work clamp, the second transfer assembly is used to move the ground wafer out of the work clamp and transfer it to the cleaning assembly, and the grinding device is composed of the wafer transfer mechanism as described above to form the second transfer assembly.

Preferably, a drying assembly is provided between the work table and the cleaning assembly, and the drying assembly dries the lower surface of the wafer transported by the second transport assembly. Effect of the invention

The first-level wafer transfer mechanism of the present invention has a wafer holding assembly for holding a wafer and a moving assembly for moving the wafer holding assembly, and the wafer holding assembly includes a suction holding portion and a water supply portion, wherein the suction holding portion has a porous surface for sucking and holding the peripheral area of the wafer, and the water supply portion is disposed on the inner side of the suction holding portion and supplies water, so that the area of the wafer sucked and held can be set smaller, and by supplying water to the wafer sucked and held by the suction holding portion, the grinding chips attached to the wafer will not dry and will not solidify. In addition, in the first-level wafer transfer mechanism of the present invention, since the area of the wafer sucked and held by the suction holding portion is smaller, the concern of grinding chips being sandwiched between the porous surface of the suction holding portion and the upper surface of the wafer can be reduced. Therefore, according to the first aspect of the wafer transfer mechanism of the present invention, it is possible to prevent the wafer from being damaged due to grinding chips attached to the wafer.

The second-level grinding device of the present invention is composed of at least a cassette loading portion, a wafer carrying assembly, a temporary assembly, a first conveying assembly, a grinding assembly, and a second conveying assembly. The cassette loading portion is used to load a cassette containing a plurality of wafers. The wafer carrying assembly is used to carry wafers out and in from the cassette loaded on the cassette loading portion. The temporary assembly is used to temporarily hold wafers carried out by the wafer carrying assembly. The first conveying assembly is used to carry wafers temporarily placed on the temporary assembly. As for the work chuck, the grinding assembly grinds the upper surface of the wafer held on the work chuck, and the second transfer assembly moves the ground wafer out of the work chuck and transfers it to the cleaning assembly. The grinding device is composed of the wafer transfer mechanism as described above to form the second transfer assembly, so the area of the wafer attracted and held can be set smaller, and by supplying water to the wafer attracted and held by the suction and holding part, the grinding shavings attached to the wafer will not dry and will not solidify. In addition, in the second-layer grinding device of the present invention, since the area of the wafer attracted and held by the suction and holding part is smaller, the concern of grinding shavings being sandwiched between the porous surface of the suction and holding part and the upper surface of the wafer can be reduced. Therefore, according to the second aspect of the present invention, the grinding device can prevent the wafer from being damaged due to grinding chips attached to the wafer.

The form used to implement the invention

Hereinafter, preferred embodiments of the wafer transfer mechanism and the grinding device according to the present invention will be described with reference to the drawings.

First, a preferred embodiment of a wafer transfer mechanism according to the present invention will be described with reference to Figures 1 to 3. As shown in Figure 1, a wafer transfer mechanism 2 includes a wafer holding assembly 4 for holding a wafer and a moving assembly 6 for moving the wafer holding assembly 4.

As shown in FIG. 2 , the wafer holding assembly 4 includes a suction holding portion 8 and a water supply portion 10 . The suction holding portion 8 has a porous surface P for sucking and holding the peripheral area of the wafer. The water supply portion 10 is disposed inside the suction holding portion 8 and supplies water.

As shown in FIG. 2 , the suction and holding portion 8 of the illustrated embodiment is composed of a plurality of (six in the illustrated embodiment) segments 12, the aforementioned segments 12 being segments formed into arc shapes by porous members such as porous ceramics, and the plurality of segments 12 are arranged in a ring shape. The segments 12 are supported by a supporting member 14, and the supporting member 14 includes a circular wall 16 and an annular wall 18 extending downward from the periphery of the circular wall 16. The plurality of segments 12 are fixed to the lower surface of the circular wall 16 at intervals in the circumferential direction and are surrounded by the annular wall 18. The outer diameter of the circumference defined by the outer peripheral surfaces 12a of the plurality of segments 12 is less than the diameter of the disc-shaped wafer W (refer to FIG. 3 ) to be held. Furthermore, each of the outer circumferential surface 12a, the inner circumferential surface 12b and the circumferential end surface 12c of each segment 12 is coated with resin, while the lower surface of each segment 12 is not coated with resin, and the lower surface of each segment 12 is formed as a porous surface P. The vertical position of the porous surface P of each segment 12 is the same.

As shown in FIG. 1 and FIG. 2(a), a plurality of (six in the illustrated embodiment) cylindrical suction ports 20 connected to each section 12 are attached to the upper surface of the circular wall 16. As shown in FIG. 1, each suction port 20 is connected to a suction source 26 via a flow path 24 provided with a valve 22. Furthermore, in the suction holding portion 8, it is formed such that the suction source 26 is actuated in a state where the valve 22 is opened and suction force is generated on the porous surface P, and as shown in FIG. 3, the periphery of the wafer W is sucked and held by the porous surface P. In this way, in the wafer holding assembly 4, since the peripheral area of the wafer W is sucked and held by a plurality of sections 12, the wafer W can still be surely sucked and held even if the width of each section 12 in the diameter direction is set smaller, and the area for sucking and holding the wafer W can be set smaller.

As shown in FIG2 , the water supply section 10 of the illustrated embodiment is composed of a plurality of (three in the illustrated embodiment) cylindrical components penetrating the circular wall 16. Each water supply section 10 is disposed radially inward of each section 12 constituting the suction and holding section 8. As shown in FIG1 , each water supply section 10 is connected to a water supply source 32 via a flow path 30 provided with a valve 28.

Furthermore, in the wafer holding assembly 4, the valve 28 is opened while the wafer W is held by the porous surface P of the suction holding portion 8, so that water from the water supply source 32 is supplied from the water supply portion 10 to the upper surface of the wafer W. When the water supplied to the upper surface of the wafer W flows out from between adjacent sections 12 and 12, the water level of the water flowing out from between adjacent sections 12 and 12 is suppressed by the annular wall 18 disposed around the suction holding portion 8. In this way, a water layer can be formed on the upper surface of the wafer W, so that the grinding chips attached to the wafer W will not dry and solidify.

As shown in FIG. 1 , the moving assembly 6 includes: a connecting shaft 34 fixed to the circular wall 16 of the supporting member 14 and extending in the up-down direction, an arm 36 extending substantially horizontally from one end connected to the upper end of the connecting shaft 34, a rotating shaft 38 fixed to the other end of the arm 36 and extending in the up-down direction, a motor (not shown) for rotating the rotating shaft 38 around the axis extending in the up-down direction, and a lifting assembly (not shown) such as an electric cylinder for lifting and lowering the rotating shaft 38.

As shown in FIG2 , the connecting shaft 34 has a cylindrical main portion 34a, a circular small diameter portion 34b formed at the lower end of the main portion 34a and having a smaller diameter than the main portion 34a, and a circular flange portion 34c formed at the upper end of the main portion 34a and having a larger diameter than the main portion 34a. The small diameter portion 34b of the connecting shaft 34 is fitted into a circular opening 16a formed at the center of the circular wall 16, thereby fixing the connecting shaft 34 to the circular wall 16.

As shown in FIG3 , a circular through opening 40 extending in the up-down direction is formed at one end of the arm 36. The connecting shaft 34 is inserted into the through opening 40 so as to be lifted and lowered. A circular recess 42 having a larger diameter than the through opening 40 is formed around the upper end side of the through opening 40. The flange 34c of the connecting shaft 34 is positioned in the recess 42, so that the connecting shaft 34 does not fall off the arm 36.

As can be understood by referring to FIG. 3 , a coil spring 44 is provided between the lower surface of one end of the arm 36 and the upper surface of the circular wall 16 of the support member 14. The coil spring 44 is arranged on the radially outer side of the main portion 34a of the connecting shaft 34. Thus, when the porous surface P of the suction holding portion 8 is positioned on the upper surface of the wafer W, the coil spring 44 is compressed to raise the suction holding portion 8 together with the support member 14, thereby relieving the impact acting on the wafer W from the porous surface P.

When the wafer transport mechanism 2 is used to transport the ground wafer W, first, the motor is used to properly rotate the rotating shaft 38 and the lifting assembly is used to properly lift it, thereby positioning the porous surface P of the suction holding portion 8 of the wafer holding assembly 4 above the peripheral area of the wafer W that has been placed on a suitable workbench (not shown). Next, the lifting assembly is used to lower the rotating shaft 38, and the porous surface P of the suction holding portion 8 is made to fit closely to the peripheral area of the upper surface of the wafer W. Next, the suction source 26 is actuated in a state where the valve 22 of the flow path 24 is opened to generate suction on the porous surface P, and as shown in FIG3 , the porous surface P is used to suck and hold the peripheral area of the upper surface of the wafer W.

Next, the valve 28 of the flow path 30 is opened to supply water from the water supply unit 10 to the upper surface of the wafer W. Next, the wafer W held by the wafer holding assembly 4 is transported by appropriately rotating the rotating shaft 38 with a motor and appropriately lifting it with a lifting assembly, and the lower surface of the wafer W is brought into contact with the upper surface of a suitable workbench (not shown) for placing the wafer W. Next, the valve 28 is closed and the supply of water from the water supply unit 10 is stopped. Then, the suction source 26 is stopped and the suction and holding of the wafer W by the porous surface P is released, and the wafer W is placed on the upper surface of the workbench. In this way, the wafer W is transported by the wafer transport mechanism 2.

As described above, in the wafer transfer mechanism 2 of the illustrated embodiment, since the peripheral area of the wafer W is held by the suction holding portion 8, the area for holding the wafer W by suction can be set smaller, and by supplying water to the wafer W held by the suction holding portion 8, the grinding shavings attached to the wafer W will not dry and will not solidify. In addition, in the wafer transfer mechanism 2, since the area for holding the wafer W by the suction holding portion 8 is smaller, the concern of the grinding shavings being caught between the porous surface P of the suction holding portion 8 and the upper surface of the wafer W can be reduced. Therefore, according to the wafer transfer mechanism 2, the situation in which the wafer W is damaged by the grinding shavings attached to the wafer W can be prevented.

Next, a preferred embodiment of the grinding device according to the present invention will be described with reference to FIG. 4. The grinding device as a whole is represented by the symbol 50, which is at least composed of a cassette loading portion 54, a wafer carrying assembly 56, a temporary assembly 58, a first conveying assembly 62, a grinding assembly 64, and a second conveying assembly. The cassette loading portion 54 is used to load a cassette 52 containing a plurality of wafers W, the wafer carrying assembly 56 is used to carry the wafers W out of and into the cassette 52 loaded on the cassette loading portion 54, and the temporary assembly 58 is used to carry the wafers W to and from the cassette 52 loaded on the cassette loading portion 54. The wafer W moved out by the wafer loading and unloading assembly 56 is temporarily placed, the first transfer assembly 62 transfers the wafer W temporarily placed in the temporary assembly 58 to the work clamp 60, the grinding assembly 64 grinds the upper surface of the wafer W held on the work clamp 60, and the second transfer assembly moves the ground wafer W out of the work clamp 60 and transfers it to the cleaning assembly 66, and the second transfer assembly is composed of the above-mentioned wafer transfer mechanism 2.

The cassette loading section 54 of the illustrated embodiment includes: a first cassette loading section 54a for loading a first cassette 52a containing a plurality of wafers W before grinding; and a second cassette loading section 54b for loading a second cassette 52b containing a plurality of wafers W after grinding. As shown in FIG. 4 , the grinding device 50 has a rectangular base 68, and the first cassette loading section 54a and the second cassette loading section 54b are arranged on the upper surface of the base 68 with a gap therebetween.

The wafer loading and unloading assembly 56 is disposed between the first cassette loading portion 54a and the second cassette loading portion 54b. The wafer loading and unloading assembly 56 includes a multi-joint arm 70 supported on a base 68, an electric or air-driven actuator (not shown) for actuating the multi-joint arm 70, and a retaining piece 72 attached to the front end of the multi-joint arm 70. The retaining piece 72, which has a plurality of suction holes (not shown) formed on one side, is connected to a suction source (not shown).

Furthermore, in the wafer loading and unloading assembly 56, it is formed as follows: by generating suction force on one side of the holding sheet 72 with a suction source, the wafer W is sucked and held by the single side of the holding sheet 72; and by actuating the multi-jointed arm 70 with an actuator, the wafer W before grinding that is sucked and held by the single side of the holding sheet 72 is moved out from the first wafer box 52a to the temporary assembly 58, and the wafer W after grinding that is sucked and held by the single side of the holding sheet 72 is moved from the cleaning assembly 66 to the second wafer box 52b.

The temporary assembly 58 is disposed on the upper surface of the base 68 and adjacent to the first cassette loading portion 54a. The temporary assembly 58 includes a circular temporary table 74 having a diameter smaller than that of the wafer W, a plurality of pins 76 disposed at intervals around the temporary table 74 so as to be freely movable in the radial direction of the temporary table 74, and a pin moving assembly (not shown) that moves the plurality of pins 76 synchronously along the radial direction of the temporary table 74. Furthermore, the temporary assembly 58 is formed such that the center of the wafer W is aligned with the center of the temporary table 74 by allowing the plurality of pins 76 to abut against the periphery of the wafer W temporarily placed on the temporary table 74.

As shown in FIG. 4 , a circular turntable 78 is rotatably provided on the upper surface of the base 68. The turntable 78 is rotated in the counterclockwise direction when viewed from above by a turntable motor (not shown) built into the base 68. Three work clamps 60 are rotatably mounted at equal intervals in the circumferential direction on the peripheral side of the upper surface of the turntable 78. The work clamps 60 are rotated around an axis extending in the vertical direction as the center by a work clamp motor (not shown) installed on the lower surface of the turntable 78. In FIG. 4 , each work clamp 60 is formed so as to be positioned in sequence to a loading and unloading position represented by symbol A, a rough grinding position represented by symbol B, and a fine grinding position represented by symbol C by the rotation of the turntable 78.

A porous circular suction chuck 80 is disposed on the upper end of each work chuck 60. The suction chuck 80 is selectively connected to a suction source (not shown) and an air supply source (not shown).

Furthermore, the work chuck 60 is formed such that a suction source generates suction force on the upper surface of the suction chuck 80 to attract and hold the wafer W placed on the upper surface of the suction chuck 80. Furthermore, the work chuck 60 is formed such that air is supplied from an air supply source to the suction chuck 80 to eject air from the upper surface of the suction chuck 80, thereby separating the wafer W from the suction chuck 80.

The first transport assembly 62 is arranged between the temporary assembly 58 and the turntable 78. The first transport assembly 62 includes: a rotating shaft 84 which is rotatably and elevatably mounted on the base 68 and extends upward from the upper surface of the base 68, an arm 86 which extends substantially horizontally from the upper end of the rotating shaft 84, an adsorption sheet 88 attached to the lower surface of the front end of the arm 86, a rotating shaft motor (not shown) for rotating the rotating shaft 84, and an elevating assembly (not shown) such as an electric cylinder for elevating the rotating shaft 84. The adsorption sheet 88 having a plurality of suction holes (not shown) formed on the lower surface is connected to a suction source (not shown).

Furthermore, in the first transfer assembly 62, a suction source is used to generate suction force on the lower surface of the suction sheet 88, so that the wafer W temporarily placed in the temporary assembly 58 is attracted and held by the lower surface of the suction sheet 88, and the rotating shaft 84 is lifted and rotated by the lifting assembly and the rotating shaft motor, so that the wafer W attracted and held by the lower surface of the suction sheet 88 is transferred from the temporary assembly 58 to the work clamp 60 positioned at the loading and unloading position A.

The grinding assembly 64 of the illustrated embodiment includes a mounting wall 90 extending upward from the end of a base 68, a first lifting plate 92 and a second lifting plate 94 each of which is installed on a single surface of the mounting wall 90 so as to be freely raised and lowered, a first lifting mechanism 96 for raising and lowering the first lifting plate 92, and a second lifting mechanism 98 for raising and lowering the second lifting plate 94.

The first lifting mechanism 96 has a ball screw 100 extending in the up-down direction along one side of the installation wall 90, and a motor 102 for rotating the ball screw 100. The nut portion (not shown) of the ball screw 100 is connected to the first lifting plate 92. In addition, in the first lifting mechanism 96, the ball screw 100 converts the rotational motion of the motor 102 into a linear motion and transmits it to the first lifting plate 92, so that the first lifting plate 92 is lifted and lowered along the guide rail 90a attached to one side of the installation wall 90. In addition, since the second lifting mechanism 98 is preferably configured the same as the first lifting mechanism 96, the same symbol as the configuration of the first lifting mechanism 96 is added, and the description is omitted.

The grinding assembly 64 includes a rough grinding unit 104 installed on one side of the first lifting plate 92, and a fine grinding unit 106 installed on one side of the second lifting plate 94. The rough grinding unit 104 includes a protruding wall 108 protruding from one side of the first lifting plate 92, a spindle 110 rotatably supported on the protruding wall 108 about an axis extending in the vertical direction, and a spindle motor 112 mounted on the upper surface of the protruding wall 108 to rotate the spindle 110. A disc-shaped wheel seat 114 is fixed to the lower end of the spindle 110, and a grinding stone 116 for rough grinding is fixed to the lower surface of the wheel seat 114. Furthermore, with respect to the fine grinding unit 106, since it is preferably configured the same as the rough grinding unit 104 except that a fine grinding grinding stone 118 formed of abrasive grains having a smaller grain size than that of the rough grinding grinding stone 116 is fixed to the lower surface of the wheel seat 114, the fine grinding unit 106 is denoted by the same symbol as the configuration of the rough grinding unit 104 and its description is omitted.

A cleaning water nozzle 120 is provided on the upper surface of the base 68 adjacent to the loading and unloading position A and spraying cleaning water. Furthermore, the upper surface of the wafer W can be cleaned by spraying cleaning water from the cleaning water nozzle 120 toward the upper surface (grinding surface) of the wafer W positioned at the loading and unloading position A after the rough grinding and the fine grinding.

As shown in FIG. 4 , the cleaning assembly 66 is disposed adjacent to the second cassette mounting portion 54 b on the upper surface of the base 68. The cleaning assembly 66 includes a circular rotating table 122 rotatably mounted on the base 68, a rotating table motor (not shown) for rotating the rotating table 122, a cleaning water nozzle (not shown) for spraying cleaning water onto the wafer W held on the rotating table 122, and an air nozzle (not shown) for spraying dry air onto the wafer W held on the rotating table 122. The diameter of the rotating table 122 is smaller than the diameter of the wafer W. Furthermore, a porous circular adsorption chuck 124 is disposed at the upper end portion of the rotary table 122, and the adsorption chuck 124 is selectively connected to a suction source (not shown) and an air supply source (not shown).

Furthermore, in the cleaning assembly 66, a suction source is used to generate suction force on the upper surface of the adsorption chuck 124, so that the rotary table 122 is used to attract and hold the wafer W, and the rotary table 122 that attracts and holds the wafer W is rotated, while the cleaning water nozzle sprays cleaning water to clean the wafer W, and the air nozzle sprays dry air to dry the wafer W. Furthermore, in the cleaning assembly 66, after the wafer W is cleaned, air is supplied from the air supply source to the adsorption chuck 124, so that the air is sprayed from the upper surface of the adsorption chuck 124, so that the wafer W is separated from the adsorption chuck 124.

The wafer transfer mechanism 2 constituting the second transfer assembly is disposed between the cleaning assembly 66 and the turntable 78, and the rotation axis 38 of the moving assembly 6 of the wafer transfer mechanism 2 is rotatably and freely mounted on the upper surface of the base 68. In addition, the wafer transfer mechanism 2 is configured to carry out the ground wafer W held by the work clamp 60 positioned at the loading and unloading position A from the work clamp 60 and transfer it to the cleaning assembly 66.

Furthermore, the grinding device 50 of the illustrated embodiment is provided with a drying assembly 126, which can dry the lower surface of the wafer W transported by the second transport assembly (wafer transport mechanism 2) between the work clamp 60 and the cleaning assembly 66. The drying assembly 126 of the illustrated embodiment has a plurality of spray holes 128 formed on the upper surface of the base 68 and an air supply source (not shown) connected to each spray hole 128, and each spray hole 128 is located below the path (transport path of the wafer W) through which the wafer holding assembly 4 of the wafer transport mechanism 2 passes. Furthermore, the drying module 126 is configured to spray dry air onto the lower surface of the wafer W held by the wafer holding module 4 during transportation, thereby drying the lower surface of the wafer W.

Next, a method for grinding wafers W using the grinding device 50 described above is described. In the illustrated embodiment, first, a cassette loading step is performed, wherein a first cassette 52a containing a plurality of wafers W before grinding is loaded on a first cassette loading portion 54a, and an empty second cassette 52b containing a plurality of wafers W after grinding is loaded on a second cassette loading portion 54b.

After the cassette loading step is performed, a temporary step is performed to carry out the wafer W from the first cassette 52a and temporarily place it on the temporary assembly 58. In the temporary step, the multi-jointed arm 70 of the wafer carrying-in and carrying-out assembly 56 is first actuated, and a single surface of a retaining sheet 72 formed with a plurality of suction holes is brought into close contact with the wafer W that has been accommodated in the first cassette 52a before the grinding process, and the retaining sheet 72 is used to attract and hold the wafer W. Then, the multi-jointed arm 70 is actuated to carry out the wafer W from the first cassette 52a, and the lower surface of the wafer W is brought into contact with the upper surface of the temporary workbench 74 of the temporary assembly 58. Then, the attraction and holding of the wafer W by the retaining sheet 72 is released, and the wafer W is temporarily placed on the temporary workbench 74. Furthermore, by allowing the plurality of pins 76 to abut against the periphery of the wafer W temporarily placed on the temporary stage 74 , the center of the wafer W is aligned with the center of the temporary stage 74 .

After the temporary placement step is performed, the first transport step is performed, and the first transport step is to transport the wafer W temporarily placed in the temporary assembly 58 to the work clamp 60. In the first transport step, the rotation shaft 84 of the first transport assembly 62 is first rotated, and the suction piece 88 of the first transport assembly 62 is positioned above the wafer W temporarily placed in the temporary assembly 58. Then, the suction piece 88 is lowered so that the lower surface of the suction piece 88 is in close contact with the upper surface of the wafer W, and the wafer W is held by the lower surface of the suction piece 88. Then, the rotation shaft 84 is raised and lowered and rotated, and the wafer W held by the suction piece 88 is transported from the temporary assembly 58 to the work clamp 60 positioned at the loading and unloading position A.

After the first transfer step is performed, a grinding step is performed to grind the upper surface of the wafer W held on the work chuck 60. In the grinding step, the wafer W is first held by the work chuck 60 by suction. Then, the turntable 78 is rotated 120 degrees, and the work chuck 60 holding the wafer W by suction is positioned at the rough grinding position B. Then, the work chuck 60 is rotated in the counterclockwise direction as viewed from above at a predetermined rotation speed, and the spindle 110 is rotated in the counterclockwise direction as viewed from above at a predetermined rotation speed. Then, the spindle 110 is lowered by the first lifting mechanism 96, and the grinding stone 116 for rough grinding is brought into contact with the upper surface of the wafer W while supplying grinding water to the grinding area. Thereafter, the spindle 110 is lowered at a predetermined grinding feed speed. Thus, the upper surface of the wafer W can be roughly ground.

Next, the turntable 78 is rotated 120 degrees, and the work chuck 60 holding the wafer W by suction is positioned at the fine grinding position C. Next, the work chuck 60 is rotated in the counterclockwise direction as viewed from above at a predetermined rotation speed, and the spindle 110 is rotated in the counterclockwise direction as viewed from above at a predetermined rotation speed, similarly to the rough grinding process. Next, the spindle 110 is lowered by the second lifting mechanism 98, and the grinding stone 118 for fine grinding is brought into contact with the upper surface of the wafer W while supplying grinding water to the grinding area. Thereafter, the spindle 110 is lowered at a predetermined grinding feed speed. In this way, the upper surface of the wafer W can be finely ground. After the fine grinding process is performed, the turntable 78 is rotated 120 degrees, and the worktable 60 holding the wafer W by suction is positioned at the loading and unloading position A. Then, cleaning water is sprayed from the cleaning water nozzle 120 toward the upper surface (grinding surface) of the wafer W, and the upper surface of the wafer W is cleaned.

After the grinding step is performed, the second transport step is performed to remove the ground wafer W from the work chuck 60 and transport it to the cleaning assembly 66. In the second transport step, first, the rotating shaft 38 of the moving assembly 6 of the wafer transport mechanism 2 constituting the second transport assembly is rotated to position the porous surface P of the suction holding portion 8 of the wafer holding assembly 4 above the peripheral area of the wafer W placed on the work chuck 60 positioned at the loading and unloading position A. Then, the suction holding portion 8 is lowered so that the porous surface P of the suction holding portion 8 is in close contact with the peripheral area of the upper surface of the wafer W, and the wafer W is sucked and held, and water is supplied to the upper surface of the wafer W from the water supply portion 10. Then, the suction and holding of the wafer W by the work chuck 60 is released.

Next, the wafer W is separated from the work table 60 by spraying a double fluid of air and water from the suction chuck 80, and the wafer holding assembly 4 is raised, so that the wafer W held by the wafer holding assembly 4 is transferred from the work table 60 to the rotary table 122 of the cleaning assembly 66. Here, when the wafer W is transferred, dry air is sprayed from each spray hole 128 of the drying assembly 126 to dry the lower surface of the wafer W being transferred. And, after the lower surface of the wafer W is brought into contact with the upper surface of the rotary table 122, the suction and holding of the wafer W by the porous surface P of the suction holding portion 8 is released.

After the second transfer step has been performed, a cleaning step is performed to clean the ground wafer W. In the cleaning step, the wafer W is first held by suction by the rotary table 122. Then, the wafer W is cleaned by spraying cleaning water from the cleaning water nozzle while the rotary table 122 is rotated. In this way, the grinding chips and grinding water attached to the wafer W can be removed to clean the wafer W, and the cleaning water can be removed from the wafer W by the centrifugal force formed by the rotation of the rotary table 122. Then, dry air is sprayed from the air nozzle while the rotary table 122 is rotated. Thereby, the cleaning water that cannot be completely removed by the centrifugal force generated by the rotation of the rotary table 122 can be removed from the wafer W, and the wafer W can be dried. Then, the suction and holding of the wafer W by the rotary table 122 is released.

After the cleaning step is performed, the cassette carrying step is performed, and the cassette carrying step is to carry out the cleaned wafer W from the cleaning assembly 66 and carry it into the second cassette 52b. In the cassette carrying step, the multi-jointed arm 70 of the wafer carrying assembly 56 is first actuated so that the single side of the retaining sheet 72 is closely attached to the wafer W placed on the rotary table 122. Then, the wafer W is separated from the suction chuck 124 by spraying air from the upper surface of the suction chuck 124 of the rotary table 122, and the wafer W is attracted and held by the retaining sheet 72. Then, the multi-jointed arm 70 is actuated to carry out the cleaned wafer W from the cleaning assembly 66 and carry it into the second cassette 52b. Furthermore, the suction and holding of the wafer W by the holding piece 72 is released.

As described above, in the grinding device 50 of the illustrated embodiment, since the second transfer assembly that transfers the ground wafer W from the work clamp 60 to the cleaning assembly 66 is composed of the wafer transfer mechanism 2, and the outer peripheral area of the wafer W is held by the suction holding portion 8, the area for holding the wafer W by suction can be set smaller, and by supplying water to the wafer W held by the suction holding portion 8, the grinding chips attached to the wafer W will not dry and will not solidify. In addition, in the grinding device 50, since the area for holding the wafer W by suction holding portion 8 is smaller, the concern of the grinding chips being sandwiched between the porous surface P of the suction holding portion 8 and the upper surface of the wafer W can be reduced. Therefore, according to the grinding device 50, it is possible to prevent the wafer W from being damaged due to the grinding chips attached to the wafer W.

2: Wafer transfer mechanism 4: Wafer holding assembly 6: Moving assembly 8: Suction holding unit 10: Water supply unit 12: Segment 12a: Outer peripheral surface 12b: Inner peripheral surface 12c: Circumferential end surface 14: Support member 16: Circular wall 16a: Circular opening 18: Annular wall 20: Suction port 22,28: Valve 24,30: Flow path 26: Suction source 32: Water supply source 34: Connecting shaft 34a: Main part 34b: Small diameter part 34c: Flange part 36,86: Arm 38: Rotating shaft 40: Through opening 42: Recess 44: Coil spring 50: Grinding device 52: Sheet cassette 52a: First sheet cassette 52b: Second sheet cassette 54: Sheet cassette loading part 54a: First sheet cassette loading part 54b: Second sheet cassette loading part 56: Wafer loading and unloading assembly 58: Temporary assembly 60: Work clamp 62: First conveyor Assembly 64: Grinding assembly 66: Cleaning assembly 68: Base 70: Multi-joint arm 72: Retaining plate 74: Temporary workbench 76: Pin 78: Turntable 80: Suction chuck 84: Rotating shaft 88: Suction plate 90: Mounting wall 90a: Guide rail 92: First lifting plate 94: Second lifting plate 96: First lifting mechanism 98: Second lifting mechanism 100: Ball screw 102: Motor 104 : Rough grinding unit 106: Fine grinding unit 108: Protruding wall 110: Spindle 112: Spindle motor 114: Wheel seat 116: Grinding stone for rough grinding 118: Grinding stone for fine grinding 120: Washing water nozzle 122: Rotating table 124: Suction chuck 126: Drying assembly 128: Spray hole A: Loading and unloading position B: Rough grinding position C: Fine grinding position P: Porous surface W: Wafer

FIG. 1 is a perspective view of a wafer transfer mechanism constructed according to the present invention. FIG. 2 (a) is a disassembled perspective view of the wafer transfer mechanism shown in FIG. 1 , and (b) is a perspective view of the wafer holding assembly shown in (a) viewed from the bottom surface side. FIG. 3 is a cross-sectional view showing a state where a wafer is held by the wafer holding assembly shown in FIG. 1 . FIG. 4 is a perspective view of a grinding device constructed according to the present invention.

4: Wafer holding assembly

6: Mobile components

8: Suction and holding part

10: Water supply department

12: Section

12a: Outer surface

12b: Inner circumference

12c: Circumferential end face

14: Support components

16: Circular wall

16a: Round opening

18: Ring wall

20: Suction port

34: Connecting shaft

34a: Main part

34b: Small path

34c: flange

36: Arm

44: Coil spring

P: Porous surface

Claims (3)

A wafer transport mechanism is a wafer transport mechanism for transporting wafers, and has a wafer holding assembly for holding the wafer, and a moving assembly for moving the wafer holding assembly. The wafer holding assembly includes a suction holding part and a water supply part. The suction holding part has a porous surface for sucking and holding the outer peripheral area of the wafer. The water supply part is arranged inside the suction holding part and supplies water. The suction holding part is composed of a plurality of sections, and the water supplied from the water supply part flows out between the adjacent sections. An annular wall is arranged around the suction holding part. The annular wall forms a water layer on the upper surface of the wafer by suppressing the water level of the water flowing out from between the adjacent sections. A grinding device is composed of at least a cassette loading portion, a wafer carrying assembly, a temporary assembly, a first conveying assembly, a grinding assembly and a second conveying assembly. The cassette loading portion is used to load a cassette containing a plurality of wafers. The wafer carrying assembly is used to carry wafers out and in from the cassette loaded on the cassette loading portion. The temporary assembly is used to carry wafers carried out by the wafer carrying assembly. The wafer is temporarily placed, the first transfer assembly is used to transfer the wafer temporarily placed on the temporary assembly to the work chuck, the grinding assembly is used to grind the upper surface of the wafer held on the work chuck, the second transfer assembly is used to transfer the ground wafer from the work chuck to the cleaning assembly, and the grinding device is composed of the wafer transfer mechanism of claim 1 to form the second transfer assembly. As in claim 2, the grinding device is provided with a drying component between the work clamp and the cleaning component, and the drying component dries the lower surface of the wafer transported by the second transport component.

Images