JP2022118429A - Grinding device and method for using grinding device - Google Patents

Abstract

To provide a grinding device and a method for using the grinding device that are able to wash a wafer placing surface without obtaining a space to be newly provided.SOLUTION: A grinding device comprises aligning means 9 comprising: a water reservoir table 92 having a diameter corresponding to a diameter of a wafer and performing alignment by means of surface tension of water W1; a water supply unit 93 that supplies water to the water reservoir table; and a washing unit 94 disposed on the water reservoir table and that washes a wafer placing surface. A method for using the grinding device includes: a water supply step of supplying water to the water reservoir table to form a water layer; an aligning step of placing a wafer on the water layer and performing alignment by means surface tension of the water; a washing step of holding the aligned wafer with a holding unit of conveying means and operating a washing unit to wash the wafer placing surface; and a conveying step of conveying the wafer from aligning means to a chuck table by the conveying means.SELECTED DRAWING: Figure 2

Description

The present invention relates to a grinding machine and a method of using the same.

A wafer having a plurality of devices such as ICs, LSIs, etc. formed on a surface partitioned by division lines is ground by a grinding device to form a desired thickness on the back surface, and then is individually separated by a dicing device and a laser processing device. device chips and used in electrical equipment such as mobile phones and personal computers.

The grinding apparatus includes a chuck table holding a wafer, grinding means rotatably supporting a grinding wheel having a grinding wheel for grinding the wafer held on the chuck table, the center of the chuck table, and the wafer. and a transport means for transporting the wafer from the alignment means to the chuck table so that the wafer can be formed to a desired thickness (for example, See Reference 1).

Japanese Patent Application Laid-Open No. 2007-317982

By the way, in the technique described in Patent Document 1, when the wafer conveyed from the table constituting the alignment means is held on the chuck table, the mounting surface (lower surface) of the wafer mounted on the chuck table. If the top surface of the wafer is ground in this state, dents (dimples) due to the dust and the like attached to the mounting surface will be formed on the grinding surface of the wafer. As a result, there is a problem that the quality of the wafer and further the quality of the device chips formed by dividing the wafer into individual pieces are degraded.

In order to deal with the above problem, it is conceivable to dispose cleaning means for cleaning the mounting surface side of the wafer in the space between the wafer transfer table from the table of the alignment means to the chuck table. However, it is necessary to secure a space between the alignment means and the chuck table for newly arranging the cleaning means. be.

The present invention has been made in view of the above facts, and its main technical problem is to newly provide cleaning means for cleaning the mounting surface side of the wafer while the wafer is transferred from the alignment means to the chuck table. It is an object of the present invention to provide a grinding apparatus capable of cleaning the mounting surface of a wafer without securing a space for cleaning, and a method of using the grinding apparatus.

In order to solve the above-mentioned main technical problems, according to the present invention, a chuck table for holding a wafer and a grinding wheel having an annular grinding wheel for grinding the wafer held by the chuck table are rotatably supported for grinding. means, alignment means for aligning the center of the chuck table with the center of the wafer, and transport means for holding and transporting the wafer from the alignment means to the chuck table with a holding portion. The alignment means comprises a water pool table having a diameter corresponding to the diameter of the wafer and performing alignment by the surface tension of water, a water supply unit for supplying water to the water pool table, and a water pool table disposed on the water pool table. and a cleaning unit for cleaning the mounting surface of the wafer.

The cleaning unit can include a cleaning nozzle that jets a mixture of water and air to clean the mounting surface of the wafer, and the cleaning nozzle is disposed in a radial area of the water pool table, Preferably, the water pool table is rotatable. Also, the cleaning section may include an ultrasonic transducer.

According to the present invention, there is provided a method for using the grinding apparatus, comprising: a water supply step of supplying water to the water pool table of the alignment means to form a water layer; An alignment step of placing a wafer on a layer and aligning the alignment using the surface tension of water, holding the aligned wafer by a holding portion of the conveying means, and operating the cleaning portion to operate the wafer mounting surface. and a transporting step of transporting the wafer from the positioning means to the chuck table by the transporting means.

Further, according to the present invention, there is provided a method of using the grinding apparatus, comprising a water supply step of supplying water to the water pool table of the alignment means to form a water layer; An alignment step of placing a wafer on a layer of water and aligning the wafer by the surface tension of water, holding the aligned wafer by a holding portion of the conveying means, and operating the washing portion to place the wafer. a cleaning step of cleaning the mounting surface; and a carrying step of carrying the wafer to the chuck table by the carrying means. A method of using a grinding apparatus for cleaning the mounting surface of a wafer by injecting the mixed two fluids is provided.

The grinding apparatus of the present invention comprises a chuck table for holding a wafer, grinding means for rotatably supporting a grinding wheel having a grinding wheel for grinding the wafer held on the chuck table, and a center of the chuck table. A grinding apparatus comprising at least positioning means for aligning the center of the wafer with the center of the wafer, and conveying means for holding and conveying the wafer from the aligning means to the chuck table with a holding portion, wherein the aligning means is a water pool table which has a diameter corresponding to the diameter of the wafer and is aligned by the surface tension of water; a water supply unit which supplies water to the water pool table; and a cleaning unit for cleaning, so that the center of the wafer can be aligned with the center position of the chuck table, and the mounting surface side of the wafer can be cleaned while the wafer is conveyed from the alignment means to the chuck table. The mounting surface of the wafer can be cleaned without providing a new cleaning means for cleaning the wafer.

Further, according to the method of using the grinding apparatus of the present invention, there are provided a water supply step of supplying water to the water pool table of the positioning means to form a water layer; An alignment step of placing a wafer and aligning it by the surface tension of water, holding the aligned wafer by a holding part of the conveying means, and actuating the cleaning part to clean the mounting surface of the wafer. and a transporting step of transporting the wafer from the positioning means to the chuck table by the transporting means. While the wafer is transferred from the alignment means to the chuck table, the mounting surface of the wafer can be cleaned without newly disposing cleaning means for cleaning the mounting surface side of the wafer.

1 is an overall perspective view of a grinding device of this embodiment; FIG. (a) Perspective view of the alignment main body portion of the alignment means 9 arranged in FIG. ) is a sectional view showing the AA section of FIG. 1 is a perspective view of a wafer, which is an object to be processed, and a protective tape attached to the wafer; FIG. (a) A perspective view showing an embodiment of a positioning process, (b) a sectional view showing a BB section of (a). FIG. 4 is a partially enlarged cross-sectional view showing an aspect of fixing a wafer in a cleaning process; FIG. 4 is a partially enlarged cross-sectional view showing a mode of cleaning a wafer by a cleaning process; FIG. 11 is a perspective view showing another embodiment of the cleaning section and cleaning process; FIG. 8 is a partially enlarged cross-sectional view showing an aspect of a cleaning process by the cleaning unit shown in FIG. 7;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a grinding apparatus constructed based on the present invention and a method of using the grinding apparatus will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a perspective view of a grinding device 1 according to this embodiment. The grinding apparatus 1 includes a chuck table 6 that holds wafers 10 (contained in a first cassette 7 in the drawing), and a grinding means (in this embodiment, a A rough grinding unit 3 and a finish grinding unit 4), positioning means 9 for aligning the center of the chuck table 6 with the center of the wafer 10, and the holding portion 13a holding the wafer 10 from the positioning means 9 to the chuck table 6. and a conveying means 13 for conveying. The rough grinding unit 3 rotatably supports a rough grinding wheel 34 having an annular grinding wheel 35 for rough grinding, and the finish grinding unit 4 has an annular grinding wheel 45 for finish grinding. A finish grinding wheel 44 is rotatably supported. As described above, the grinding apparatus 1 of this embodiment includes the rough grinding unit 3 and the finish grinding unit 4, but the present invention is not limited to this. Three or more may be provided. The grinding device 1 of this embodiment will be described in more detail.

The grinding device 1 includes a substantially rectangular parallelepiped device housing 2 . In FIG. 1, a support wall 21 is erected on the rear end side of the device housing 2 (back side in the Y direction in the drawing). Two pairs of vertically extending guide rails 22 , 22 and 23 , 23 are arranged on the inner surface of the support wall 21 . A rough grinding unit 3 as rough grinding means is mounted on one of the guide rails 22, 22 so as to be movable in the vertical direction, and a finish grinding unit 4 as finish grinding means is mounted on the other guide rails 23, 23. It is mounted so as to be vertically movable.

The rough grinding unit 3 includes a unit housing 31, a wheel mount 33 disposed at the lower end of a rotating shaft 32 rotatably supported by the unit housing 31, and a plurality of grinding wheels annularly mounted on the wheel mount 33 on the lower surface. 35 is arranged, an electric motor 36 mounted on the upper end of the unit housing 31 and rotating the wheel mount 33 in the direction indicated by the arrow R1, and a movement supporting the unit housing 31 via a support member 37 A base 38 is provided.

The finish grinding unit 4 has substantially the same structure as the rough grinding unit 3, and includes a unit housing 41, a wheel mount 43 disposed at the lower end of a rotary shaft 42 rotatably supported by the unit housing 41, and a wheel. A finish grinding wheel 44 mounted on a mount 43 and having a plurality of grinding wheels 45 annularly arranged on the lower surface, an electric motor 46 mounted on the upper end of the unit housing 41 and rotating the wheel mount 43 in the direction indicated by the arrow R2, A movable base 48 that supports the unit housing 41 via a support member 47 is provided.

The movable base 38 is provided with guide grooves slidably engaged with the guide rails 22, 22 provided on the support wall 21, and supports the rough grinding unit 3 so as to be vertically movable. be done. The support wall 21 is provided with a grinding feed mechanism 39 for moving the movable base 38 of the rough grinding unit 3 up and down along the guide rails 22 , 22 . The grinding feed mechanism 39 includes a male threaded rod 391 arranged vertically in parallel with the guide rails 22 and rotatably supported, a pulse motor 392 for rotating the male threaded rod 391, and a moving base 38. A female threaded block (not shown) is mounted on the rear side of the unit and screwed with the male threaded rod 391. By rotating the male threaded rod 391 forward and backward by a pulse motor 392, the rough grinding unit 3 is moved in the Z direction (vertical direction). ).

The movable base 48 is provided with guide grooves that slidably engage with the guide rails 23, 23 provided on the support wall 21, and supports the finish grinding unit 4 so as to be vertically movable. be done. The support wall 21 is provided with a grinding feed mechanism 49 for moving the movable base 48 of the finish grinding unit 4 up and down along the guide rails 23 , 23 . The grinding feed mechanism 49 includes a male threaded rod 491 vertically arranged on the support wall 21 in parallel with the guide rails 23 and rotatably supported, a pulse motor 492 for rotationally driving the male threaded rod 491, A female threaded block (not shown) is mounted on the rear side of the moving base 48 and screwed with the male threaded rod 491. By rotating the male threaded rod 491 forward and backward by a pulse motor 492, the finish grinding unit 4 is rotated in the Z direction. direction (vertical direction).

The rotary shaft 32 rotated by the electric motor 36 of the rough grinding unit 3 and the electric motor 46 of the finish grinding unit 4 and the rotary shaft 42 are mounted on the grinding wheels 35 and 45 and the wafer 10 held on the chuck table 6 which will be described later. Grinding water supply means (not shown) for supplying grinding water is connected. Grinding water pressure-fed from the grinding water supply means is supplied to the rotating shaft 32 and the rotating shaft 42, and is directed from the center of the lower end surface of the rough grinding wheel 34 and the finish grinding wheel 44 to the grinding wheel 35 and the grinding wheel 45. sprayed horizontally.

The grinding machine 1 in the illustrated embodiment comprises a turntable 5 arranged on the front side of the support wall 21 so as to be substantially flush with the upper surface of the machine housing 2 . The turntable 5 is formed in the shape of a disk having a relatively large diameter, and is appropriately rotated in the direction indicated by an arrow R3 by a rotation drive mechanism (not shown). In the illustrated embodiment, three chuck tables 6 are arranged on the turntable 5 at an angle of 120 degrees each. 3 and directly below the finish grinding unit 4, it is configured to be rotatable in the direction indicated by the arrow R4. The chuck table 6 includes a disk-shaped suction chuck 61 that forms a holding surface of the chuck table 6 and a frame 62 that surrounds the suction chuck 61 .

The three chuck tables 6 arranged on the turntable 5 are rotated in the direction indicated by the arrow R3, whereby the workpiece loading/unloading area A→rough grinding area B→finish grinding. Area C→Work piece loading/unloading area A is sequentially moved.

The illustrated grinding apparatus 1 includes a first cassette 7 disposed on one side (the front side in the X direction in the drawing) of a workpiece carry-in/carry-out area A for accommodating wafers 10 before grinding; A second cassette 8 disposed on the other side (back side in the X direction in the figure) of the object carry-in/carry-out area A for accommodating the wafers 10 after grinding, a first cassette 7 and the workpiece carry-in/carry-out area A; positioning means 9 disposed between the unloading area A and aligned with the center of the chuck table 6 positioned in the workpiece loading/unloading area A and the center of the wafer 10; The cleaning means 11 arranged between A and the second cassette 8 and the wafers 10 stored in the first cassette 7 are unloaded and conveyed to the alignment means 9, and the wafers are removed from the cleaning means 11. The wafer 10 aligned by the alignment means 9 is positioned in the workpiece loading/unloading area A from the alignment means 9. and a conveying means 14 for conveying the ground wafer 10 placed on the chuck table 6 positioned in the workpiece loading/unloading area A to the cleaning means 11. and have.

An operation panel 15 for instructing a grinding operation and designating machining conditions is arranged on the front side in the Y direction of the device housing 2 where the conveying means 12 is arranged. In addition to the above configuration, the grinding apparatus 1 has a display monitor that displays the state of the grinding process and has a touch panel function so that work instructions can be given as appropriate, and a control means that controls each operating mechanism. etc. are provided, and the entire grinding apparatus 1 is covered with a cover, the description of which is omitted for convenience of explanation.

As shown in FIG. 1, the alignment means 9 includes an alignment main body portion 90 and a collection pool 91 surrounding the alignment main body portion 90 for collecting and discharging washing water flowing out from the alignment main body portion 90 . Prepare. The recovery pool 91 includes a cylindrical peripheral wall portion 91a with an open top, a bottom wall portion 91b, and a discharge hole 91c formed in the bottom wall portion 91b. The water flowing out from the alignment main body 90 is collected in the recovery pool 91 and discharged from the drain hole 91c of the bottom wall 91b. discharged into the tank. The alignment body 90 of the alignment means 9 will be described more specifically with reference to FIG.

As shown in FIG. 2(a), the alignment main body 90 has a diameter corresponding to the diameter of the wafer 10 (see FIG. 3), which will be described later in detail, and is a water pool table that performs alignment using the surface tension of water. 92 , a water supply unit 93 for supplying water to the water pool table 92 , and a cleaning unit 94 disposed on the water pool table 92 for cleaning the mounting surface of the wafer 10 . The water pool table 92 includes a circular bottom portion 92a and a peripheral wall 92b surrounding the bottom portion 92a. The water supply part 93 and the washing part 94 of this embodiment are arranged on the bottom part 92 a of the water pool table 92 . The cleaning section 94 includes, for example, four cleaning nozzles 941 to 944 arranged in series in a radial region (region between the center of the bottom portion 92a and the peripheral wall 92b). FIG. 2(b) shows a perspective view of the cleaning nozzles 941 to 944 constituting the cleaning section 94 and a connecting block 940 connecting the cleaning nozzles 941 to 944, and FIG. 2 shows a sectional view showing the AA section; FIG. As can be seen from FIG. 2(c), inside the connecting block 940, an air supply path 98 extending in the longitudinal direction of the connecting block 940 through which the air P supplied from the air supply source 120 is introduced, and a high pressure Water W2 supplied from a water supply source 130 is introduced, and a high-pressure water supply path 99 extending in the longitudinal direction of the connecting block 940 is arranged in parallel with the air supply path 98. The air supply path 98 and the high-pressure water supply path 99 and are merged in the connection block 940 and connected to the cleaning nozzle 944 . Since the cleaning nozzles 941 to 943 are also connected to the air supply path 98 and the high-pressure water supply path 99 in the same manner as described above, by operating the air supply source 120 and the high-pressure water supply source 130, they can be connected. A mixed two-fluid is generated by mixing the air P and the water W2 in the block 940, and is simultaneously jetted upward from the jet ports 941a-944a of the cleaning nozzles 941-944.

As shown in the drawing, the upper end of a rotary shaft 95 is connected and fixed to the lower surface of the water pool table 92 . The rotating shaft 95 is rotationally driven by an electric motor 96 in the direction indicated by an arrow R5. A rotary joint 97 is arranged at the lower end of the rotating shaft 95 . Three paths (not shown) are formed inside the rotating shaft 95, and the water supply unit 93 and the low-pressure water supply source 110 are connected via the three paths and the rotary joint 97, The cleaning unit 94 is connected to an air supply source 120 and a high-pressure water supply source 130 .

The rotary joint 97 and the low-pressure water supply source 110 are connected by a communication path 112 in which an on-off valve 114 is arranged. The rotary joint 97 and the air supply source 120 are connected by a communication path 122 , and an open/close valve 124 is arranged in the communication path 122 . The rotary joint 97 and the high-pressure water supply source 130 are connected by a communication path 132, and an opening/closing valve 134 is arranged in the communication path 132. As shown in FIG. In the illustrated embodiment, a drainage channel 116 is connected to the communicating passage 112 and a drainage control valve 118 is arranged in the drainage channel 116 . The open/close valves 114, 124, and 134 and the drain valve 118 are connected to control means (not shown), and the open/closed states are controlled by the control means. The water pressure of the water W1 supplied from the low-pressure water supply source 110 is a pressure corresponding to the so-called standard pressure at the time of distributing tap water, and the water pressure of the water W2 supplied by the high-pressure water supply source 130 is, for example, the water W1 is set to about 0.3 Mpa, which is higher than Also, the pressure of the air P supplied by the air supply source 120 is set to 0.3 Mpa. The open/close valves 114, 124, 134 and the drain valve 118 are not limited to being opened/closed by the control means, and may be manually opened/closed. Further, when water of different pressure (or different flow rate) can be supplied from the high-pressure water supply source 130, the low-pressure water supply source 110 is omitted by providing the high-pressure water supply source 130 with the function of the low-pressure water supply source 110. is also possible.

By using the above-described positioning means 9 and carrying out the positioning process described later, the center position of the water pool table 92 of the positioning means 9 and the center position of the wafer 10 are made to match. is used to match the center position of the wafer 10 conveyed from the water pool table 92 with the center position of the chuck table 6 described above.

The grinding machine 1 of the present embodiment generally has the configuration described above, and the method of using the grinding machine 1 and its effects will be described below.

The workpiece to be ground in this embodiment is a silicon (Si) wafer 10 formed on a surface 10a where a plurality of devices D are partitioned by dividing lines L, as shown in FIG. A protective tape T is adhered to the surface 10a of the wafer 10 to integrate them. In the first cassette 7 of the grinding apparatus 1 shown in FIG. 1, a plurality of wafers 10 to which the protective tapes T are adhered and integrated are accommodated.

When the first cassette 7 containing a plurality of wafers 10 is set in the grinding apparatus 1 shown in FIG. It is positioned in the goods carry-in/carry-out area A. Next, the conveying means 12 is operated to unload the unprocessed wafer 10 from the first cassette 7 and convey it to the alignment means 9 . Here, the open/close valve 114 of the communication passage 112 of the alignment main body 90 described with reference to FIG. As a result, as shown in FIG. 4(a), water W1 is supplied from a water supply portion 93 disposed on the bottom portion 92a of the water pool table 92, and the water pool table 92 is formed by the bottom portion 92a and the peripheral wall 92b. Sufficient water W1 is supplied to fill the volume, and the on-off valve 114 is closed. As a result, a layer of water W1 that bulges upward from the water reservoir table 92 is formed by the action of surface tension (water supply step). After the water supply step is performed, as shown in FIG. 4B, the wafer 10 transported to the alignment means 9 is placed with the protective tape T side serving as the mounting surface facing downward and the back surface 10b facing upward. , and is placed on the layer of water W1 formed on the water pool table 92. As shown in FIG. By placing the wafer 10 on the layer of water W1 formed in the water pool table 92 in this manner, the horizontal position of the wafer 10 is adjusted by the action of the surface tension of the water W1, and the central position of the wafer 10 is adjusted. and the center position of the water pool table 92 (positioning step).

As described above, when the wafer 10 is aligned on the layer of water W1 formed on the water pool table 92, as shown in FIG. The holding portion 13a of the means 13 is positioned above the center of the water pool table 92 (=the center of the wafer 10), lowered in the direction indicated by the arrow R6, and positioned in contact with the rear surface 10b of the wafer 10. FIG. Next, the suction means (not shown) is operated to generate suction negative pressure V on the lower surface side of the holding portion 13a through the transfer means 13, thereby attracting the wafer 10 and fixing it. After the position of the wafer 10 is fixed by the holding portion 13a, the open/close valve 18 is opened and the water W1 stored in the water pool table 92 is discharged through the drainage channel 116. FIG.

Next, the electric motor 96 is operated to rotate the water pool table 92 together with the rotating shaft 95 in the direction indicated by the arrow R5 (for example, 60 rpm), as shown in FIG. Next, the opening/closing valve 124 on the communicating path 122 and the opening/closing valve 134 on the communicating path 132 are opened, and the air supply source 120 and the high-pressure water supply source 130 are operated. As a result, the air P and the water W2 are supplied to the cleaning nozzles 941 to 944 constituting the cleaning section 94, and the mixed two-fluid (P+W2) formed by the air P and the water W2 is jetted from the cleaning nozzles 941 to 944. be. Here, since the water pool table 92 is rotating in the direction indicated by R5, the mixed two fluids (P+W2) are directed to the protective tape T side of the wafer 10 fixed on the water pool table 92, that is, to the chuck table 6. The entire mounting surface side to be mounted is sprayed, and the mounting surface side is satisfactorily cleaned (washing process). When the washing process is completed, the operation of the air supply source 120 and the high-pressure water supply source 130 is stopped, and the opening/closing valve 124 on the communicating path 122 and the opening/closing valve 134 on the communicating path 132 are closed. . At this time, by stopping the high-pressure water supply source 130 and closing the opening/closing valve 134 prior to stopping the operation of the air supply source 120 and closing the opening/closing valve 124, the wafer 10 can be placed. Only the air P is jetted to the surface, and the water W2 adhering to the mounting surface side can be removed. It should be noted that the water W1 and W2 leaking from the water pool table 92 to the outside in the above-described alignment process and cleaning process are collected by the above-described collection pool 91, and are disposed in the bottom wall portion 91b of the collection pool 91. It is discharged from the hole 91c.

The wafer 10 on which the above-described positioning process and cleaning process have been performed is transported using the transport means 13, and the suction chuck 61 of the predetermined chuck table 6 positioned in the workpiece loading/unloading area A shown in FIG. place on top. The center position of the wafer 10 transported to the chuck table 6 and the center position of the chuck table 6 are aligned by performing the above-described positioning process and aligning the center position of the water pool table 92 with the center position of the wafer 10 . are also consistent. Then, the suction means (not shown) is operated to suck and hold the wafer 10 on the suction chuck 61 of the chuck table 6 .

Next, the turntable 5 is rotated in the direction indicated by the arrow R3 in FIG. Move to region B.

After the chuck table 6 holding the unprocessed wafer 10 is positioned in the rough grinding processing zone B, the rough grinding process described below is carried out. More specifically, the wafer 10 held on the chuck table 6 is positioned directly below the rough grinding wheel 34, the chuck table 6 is rotated in the direction indicated by the arrow R4 at, for example, 300 rpm, and at the same time the rough grinding unit 3 is rotated. In operation, coarse grinding wheel 34 is rotated in the direction indicated by arrow R1 in the figure at, for example, 6000 rpm. Then, the above-described grinding feed mechanism 39 is operated to lower the rough grinding unit 3, and the grinding wheel 35 is brought into contact with the back surface 10b of the wafer 10 from above. Grinding feed at speed. At this time, grinding water supply means (not shown) is operated to supply grinding water from the lower surface of the rough grinding wheel 34 toward the grinding wheel 35 and the back surface 10 b of the wafer 10 .

When performing the rough grinding process described above, if the wafer 10 after the rough grinding process is positioned in the adjacent finish grinding zone C, at the same time as performing the rough grinding process, The finish grinding unit 4 is operated in the same manner as the rough grinding unit 3, and the finish grinding wheel 44 is brought into contact with the wafer 10, so that the back surface 10b of the wafer 10 is subjected to the finish grinding process. The grinding feed speed of the grinding feed mechanism 49 of the finish grinding unit 4 is set slower than the grinding feed speed of the rough grinding unit 3 (for example, 0.1 μm/second).

After the rough grinding process and the finish grinding process have been carried out, the transfer means 14 is moved from the chuck table 6 positioned in the workpiece loading/unloading area A by rotating the turntable 5 in the direction indicated by R3. In operation, the wafer 10 subjected to the grinding process is conveyed to the cleaning means 11, and the grinding surface (back surface 10b) of the wafer 10 is cleaned and dried. Next, the transport means 12 is operated to transport the cleaned and dried wafers 10 from the cleaning means 11 to a predetermined position in the second cassette 8 .

As described above, in this embodiment, the center position of the wafer 10 is positioned at the center position of the water pool table 92 by performing the positioning process using the positioning means 9 . As a result, the center of the wafer 10 can be aligned with the center position of the chuck table 6 positioned in the workpiece loading/unloading area A by the holding portion 13 a of the transport means 13 . Since the mounting surface of the wafer 10 is washed by the washing unit 94 of the water pool table 92 , the mounting surface side of the wafer 10 is washed while the wafer 10 is transferred from the positioning means 9 to the chuck table 6 . It is possible to clean the mounting surface of the wafer 10 without newly arranging a cleaning means for cleaning, and as a result, when performing the above-described grinding process, a dent caused by dust etc. is also avoided from being formed.

In the above-described embodiment, the cleaning unit 94 includes cleaning nozzles 941 to 944 for cleaning the mounting surface of the wafer 10 by injecting a mixed two-fluid (P+W2) in which high-pressure water W2 and air P are mixed. Although an example has been shown, the present invention is not limited to this. 7 and 8, an alignment body portion 90' having a cleaning portion 140 having a configuration different from that of the cleaning portion 94 provided in the alignment means 9 will be described.

FIG. 7 shows a portion of alignment body 90' with cleaning portion 140. As shown in FIG. The alignment main body 90' has a diameter corresponding to the diameter of the wafer 10 (see FIG. 3) which is a workpiece, and has a water pool table 92' for alignment using the surface tension of water. and a cleaning unit 140 disposed in the water pool table 92' and cleaning the mounting surface of the wafer 10. As shown in FIG. The water pool table 92' has a circular bottom portion 92a' and a peripheral wall 92b' surrounding the bottom portion 92a'. The water supply part 93' and the cleaning part 140 of this embodiment are arranged on the bottom part 92a' of the water pool table 92'.

The cleaning unit 140 includes ultrasonic transducers 142 and 144 arranged on the bottom 92a' of the water pool table 92'. The ultrasonic transducers 142 and 144 are vibrated using, for example, electrostrictive vibrating elements using lead zirconate titanate (PZT), and are vibrated at a frequency of, for example, 20 kHz to 100 kHz. The ultrasonic transducer 142 is annularly formed and disposed on the bottom 92a' of the water pool table 92'. An ultrasonic transducer 144 is disposed in the center of the bottom 92a' of the basin table 92'. The water supply part 93 ′ is arranged in a region between the ultrasonic transducers 142 and 144 .

As shown in the figure, the upper end of the rotating shaft 95 is connected to the lower surface of the water pool table 92'. The structure below the rotating shaft 95 is the same as that of the positioning body 90 described with reference to FIG. and a rotary joint 97 connecting with a communication passage 112 extending from the source 110 . 7 and 8 does not include the cleaning nozzles 941 to 944 shown in FIG. , 132 are unnecessary.

As shown in FIG. 7, a water reservoir table 92' is filled with water W1 from a water supply unit 93' to form a layer of water W1, and the protective tape T (mounting surface) side of the wafer 10 is placed. . As described with reference to FIG. 4B, the center position of the water pool table 92' and the center position of the wafer 10 are changed by the action of the surface tension of the water W1 stored in the water pool table 92'. Once aligned, the positioning process is performed. 5, the conveying means 13 is operated to position the holding portion 13a of the conveying means 13 at the center position of the rear surface 10b of the wafer 10 as shown in FIG. 10 is fixed on the pool table 92'. After the wafer 10 is fixed on the water pool table 92', a high frequency voltage (20 to 100 kHz) is applied to the ultrasonic transducers 142 and 144 via the wiring 146 arranged inside the rotating shaft 95 to vibrate. Then, the surface of the wafer 10 on the side of the protective tape T, that is, the mounting surface is washed through the layer of water W1 stored in the water pool table 92' (washing step). After the cleaning process is carried out in this manner, the holding portion 13a of the transporting means 13 is raised in the direction indicated by the arrow R7 in the drawing, and the wafer is transported to the chuck table 6. And a finish grinding process is carried out. When cleaning the mounting surface of the wafer 10 with the ultrasonic oscillators 142 and 144, a layer of water W1 must exist between the water pool table 92' and the protective tape T of the wafer 10. Therefore, it is preferable to open the on-off valve 114 and continue to supply the water W1 from the water supply portion 93'. At this time, it is not necessary to rotate the rotating shaft 95 by the electric motor 96 .

The alignment main body portion 90' described above can also achieve the same effects as the alignment main body portion 90' described above. Further, in the above-described embodiment, instead of the cleaning unit 94 having the cleaning nozzles 941 to 944, the cleaning unit 140 having the ultrasonic transducers 142 and 144 is provided. and ultrasonic transducers.

1: Grinding Device 2: Device Housing 21: Support Walls 22, 23: Guide Rail 3: Rough Grinding Unit 31: Unit Housing 32: Rotary Shaft 33: Wheel Mount 34: Rough Grinding Wheel 35: Grinding Wheel 36: Electric Motor 37: Support member 39: Grinding feed mechanism 4: Finish grinding unit 41: Unit housing 42: Rotary shaft 43: Wheel mount 44: Finish grinding wheel 45: Grinding wheel 46: Electric motor 47: Support member 49: Grinding feed mechanism 5: Turntable 6: Chuck table 61: Suction chuck 7: First cassette 8: Second cassette 9: Positioning means 90, 90': Positioning body 91: Recovery pool 91a: Peripheral wall 91b: Bottom wall 91c: Ejection Holes 92, 92': Water pool tables 92a, 92a': Bottoms 92b, 92b': Peripheral walls 93, 93': Water supply part 94: Washing part 940: Connecting blocks 941 to 944: Washing nozzle 95: Rotating shaft 96: Electric motor 97: Rotary Joint 10: Wafer 11: Washing Means 12: Conveying Means 13: Conveying Means 13a: Holding Part 14: Conveying Means 15: Operation Panel 110: Low Pressure Water Supply Source 112: Communication Path 114: Opening/Closing Valve 116: Drainage Path 118 : Drainage valve 120: Air supply source 122: Communication passage 124: Open/close valve 130: High pressure water supply source 132: Communication passage 134: Open/close valve 140: Washing unit 142, 144: Ultrasonic transducer D: Device L: Line to be divided T: Protective tape P: Air W1, W2: Water P+W2: Mixed 2 fluids

Claims (6)

A chuck table holding a wafer, a grinding means rotatably supporting a grinding wheel having an annular grinding wheel for grinding the wafer held on the chuck table, and the center of the chuck table and the center of the wafer being aligned. and a conveying means for holding and conveying a wafer from the aligning means to the chuck table with a holding portion,
The alignment means includes a water pool table having a diameter corresponding to the diameter of the wafer and performing alignment using the surface tension of water, a water supply section for supplying water to the water pool table, and a wafer disposed on the water pool table. and a cleaning unit for cleaning the mounting surface of the grinding apparatus. 2. The grinding apparatus according to claim 1, wherein the cleaning unit includes a cleaning nozzle for cleaning the mounting surface of the wafer by injecting a mixed two-fluid of water and air. 3. The grinding apparatus according to claim 2, wherein said cleaning nozzle is arranged in a radial area of said water pool table, and said water pool table is rotatable. 3. The grinding apparatus according to claim 1, wherein said cleaning unit includes an ultrasonic oscillator. A method of using the grinding apparatus according to any one of claims 1 to 4,
a water supply step of supplying water to the water pool table of the alignment means to form a layer of water;
an alignment step of placing the wafer on a layer of water formed on the water pool table and aligning the wafer with the surface tension of the water;
a cleaning step of holding the aligned wafer by a holding portion of the conveying means and operating the cleaning portion to clean the mounting surface of the wafer;
a conveying step of conveying the wafer from the alignment means to the chuck table by the conveying means;
A method of using a grinding device comprising: A method of using the grinding apparatus according to claim 3,
a water supply step of supplying water to the water pool table of the alignment means to form a layer of water;
an alignment step of placing the wafer on a layer of water formed on the water pool table and aligning the wafer with the surface tension of the water;
a cleaning step of holding the aligned wafer by a holding portion of the conveying means and operating the cleaning portion to clean the mounting surface of the wafer;
a conveying step of conveying the wafer to the chuck table by the conveying means;
including
A method of using the grinding apparatus, wherein in the cleaning step, the water pool table is rotated and the mixed two fluids are jetted from the cleaning nozzle to the wafer mounting surface to clean the wafer mounting surface.

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