JP2005302831A - Grinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinder provided with a cleaning mechanism which can clean a workpiece without peeling the workpiece adhered to the workpiece. <P>SOLUTION: The grinder is provided with a chuck table, a grinding means, a workpiece carry-out means 37 having suction pads 372, and cleaning means. The cleaning means is equipped with an electric motor that can rotate/drive a cylindrical cleaning roller 382 in normal or reverse direction, and it is also provided with a detection means that can detect a timing when the central part of the suction pad 372 arrives at the cleaning roller 382, and a control means to control the rotational direction of the electric motor on the basis of a detection signal issued from the detection means. The control means controls the electric motor so that it may rotate in normal direction until the central part of the suction pad 372 arrives at the cleaning roller 382 and may rotate in reverse direction after the central part of the suction pad 372 arrives at the cleaning roller 382. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a grinding apparatus provided with cleaning means for cleaning a lower surface of a workpiece ground by a grinding means on a chuck table.

  As is well known to those skilled in the art, in a semiconductor device manufacturing process, a semiconductor wafer in which a plurality of circuits such as ICs and LSIs are formed is ground by a grinding device on the back surface before being divided into individual chips. It is formed in the thickness. A grinding apparatus for grinding the back surface of a semiconductor wafer includes a chuck table for sucking and holding a workpiece, a grinding means for grinding the workpiece sucked and held on the chuck table, and a workpiece ground on the chuck table. A workpiece unloading means for sucking and holding the workpiece is provided.

  When grinding the back surface of the semiconductor wafer using the above-described grinding apparatus, the surface side of the semiconductor wafer is held on the chuck table, so that the semiconductor formed on the surface of the semiconductor wafer is prevented from being damaged. A protective member made of polyvinyl chloride or the like is attached to the surface of the wafer. However, if the back surface of the semiconductor wafer is ground with the protective member attached to the surface of the semiconductor wafer and sucked and held on the chuck table, the grinding waste generated by grinding is sucked into the chuck table and enters between the protective member. And adheres to the surface of the protective member. If grinding scraps adhere to the surface of the protective member, there is a problem that the protective member is hindered when the protective member is peeled off from the semiconductor wafer or becomes a contamination source in subsequent processes.

  On the other hand, grinding dust also adheres to the suction surface of the suction pad for sucking and holding the workpiece in the workpiece unloading means for unloading the ground workpiece from the chuck table. When grinding scraps adhere to the suction surface of the suction pad, there is a problem that a workpiece formed as thin as a semiconductor wafer breaks when sucked.

In order to solve the above-described problem, a grinding apparatus has been proposed in which a cleaning unit that cleans the suction surface of the suction pad is disposed on the suction path of the suction pad that constitutes the workpiece discharge unit. (For example, see Patent Document 1)
JP 2003-45841 A

  The cleaning means disclosed in the above Japanese Patent Application Laid-Open No. 2003-45841 is configured to rotate a cylindrical cleaning brush and pass the suction surface of the suction pad in contact with the rotating cleaning brush. The surface can be cleaned effectively. It is also possible to clean the lower surface of the workpiece sucked and held by the suction pad using this cleaning means.

  Thus, when the surface of the protective member attached to the surface of the semiconductor wafer sucked and held by the suction pad is cleaned using the cleaning means described above, the outer peripheral portion of the protective member is caused by the rotation of the cleaning brush. The problem of peeling from the semiconductor wafer occurred. That is, when the rotation direction of the cleaning brush is opposite to the moving direction of the semiconductor wafer at the position facing the cleaning wafer and the semiconductor wafer held by the suction pad, cleaning is performed on the protective member attached to the surface of the semiconductor wafer. The outer peripheral surface that comes into contact with the brush is peeled off. In addition, when the rotation direction of the cleaning brush is set to be the forward direction with the moving direction of the semiconductor wafer at a position facing the semiconductor wafer, the outer peripheral surface of the protective member attached to the surface of the semiconductor wafer on the side passing through the cleaning brush Was found to peel.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to provide a grinding apparatus provided with cleaning means that can clean the protective member attached to the workpiece without peeling it off. There is.

In order to solve the main technical problem, according to the present invention, a chuck table for holding a workpiece, a grinding means for grinding the workpiece held on the chuck table, and grinding on the chuck table are performed. A workpiece unloading means having a suction pad for sucking and holding the workpiece, and a cleaning means for cleaning the workpiece disposed on the suction pad unloading path and sucked and held by the suction pad. In the grinding device
The cleaning means includes a cylindrical cleaning roller, and an electric motor capable of normal rotation and reverse rotation for rotationally driving the cleaning roller.
Detecting means for detecting a time point when the central portion of the suction pad reaches the cleaning roller;
Control means for controlling the rotation direction of the electric motor based on a detection signal from the detection means,
The control means includes the electric motor so that the rotation direction of the cleaning roller is forward with the moving direction of the suction pad at a position facing the suction pad until the center of the suction pad reaches the cleaning roller. The electric motor so that when the central portion of the suction pad reaches the cleaning roller, the rotation direction of the cleaning roller is opposite to the moving direction of the suction pad at a position facing the suction pad. Drive in reverse,
A grinding device is provided.

  Since the grinding device according to the present invention is configured as described above, the workpiece sucked and held by the suction pad constituting the workpiece unloading means is attached to the workpiece when passing through the cleaning roller. The outer periphery on the side where the protective member begins to contact the cleaning roller and the outer periphery on the side passing through the cleaning roller are cleaned without peeling.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a grinding apparatus configured according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a grinding apparatus provided with a workpiece unloading mechanism constructed according to the present invention.
The grinding device in the illustrated embodiment includes a device housing 2 having a substantially rectangular parallelepiped shape. A stationary support plate 4 is erected on the upper right end of the device housing 2 in FIG. Two pairs of guide rails 6, 6 and 8, 8 extending in the vertical direction are provided on the inner surface of the stationary support plate 4. A rough grinding unit 10 as rough grinding means is mounted on one of the guide rails 6 and 6 so as to be movable in the vertical direction. A finish grinding unit 12 as finish grinding means is vertically mounted on the other guide rails 8 and 8. It is mounted to move in the direction.

  The rough grinding unit 10 includes a unit housing 101, a grinding wheel 102 rotatably attached to the lower end of the unit housing 101, and a grinding wheel 102 attached to the upper end of the unit housing 101 in a direction indicated by an arrow 102a. And a movable base 104 on which the unit housing 101 is mounted. Guided rails 105, 105 are provided on the moving base 104, and the guided rails 105, 105 are movably fitted to the guide rails 6, 6 provided on the stationary support plate 4. The rough grinding unit 10 is supported so as to be movable in the vertical direction. The rough grinding unit 10 in the illustrated form includes a feed mechanism 11 that moves the moving base 104 along the guide rails 6 and 6 and adjusts the cutting depth of the grinding wheel 102. The feed mechanism 11 includes a male screw rod 111 that is disposed on the stationary support plate 4 in parallel with the guide rails 6 and 6 and is rotatably supported, and a pulse motor 112 that rotationally drives the male screw rod 111. , A female screw block (not shown) mounted on the moving base 104 and screwed to the male screw rod 111 is provided, and the male screw rod 111 is driven forward and reverse by a pulse motor 112 to move the rough grinding unit 10 in the vertical direction. Move to.

  The finish grinding unit 12 is also configured in the same manner as the rough grinding unit 10, and is equipped with a unit housing 121, a grinding wheel 122 rotatably attached to the lower end of the unit housing 121, and an upper end of the unit housing 121. A rotation drive mechanism 123 that rotates the grinding wheel 122 in a direction indicated by an arrow 122a and a moving base 124 on which the unit housing 121 is mounted are provided. Guided rails 125, 125 are provided on the moving base 124, and the guided rails 125, 125 are movably fitted to the guide rails 8, 8 provided on the stationary support plate 4. The finish grinding unit 12 is supported so as to be movable in the vertical direction. The finish grinding unit 12 in the illustrated form includes a feed mechanism 13 that moves the moving base 124 along the guide rails 8 and 8 and adjusts the cutting depth of the grinding wheel 122. The feed mechanism 13 has substantially the same configuration as the feed means 11. That is, the feed mechanism 13 includes a male screw rod 131 which is disposed on the stationary support plate 4 in the vertical direction in parallel with the guide rails 6 and 6 and is rotatably supported, and a pulse motor for driving the male screw rod 131 to rotate. 132 and a female screw block (not shown) that is mounted on the moving base 124 and is screwed with the male screw rod 131. By driving the male screw rod 121 forward and backward by the pulse motor 132, the finish grinding unit 12 is moved. Move it up and down.

  The grinding apparatus in the illustrated embodiment includes a turntable 15 disposed so as to be substantially flush with the upper surface of the apparatus housing 2 on the front side of the stationary support plate 4. The turntable 15 is formed in a relatively large-diameter disk shape, and is appropriately rotated in a direction indicated by an arrow 15a by a rotation drive mechanism (not shown). In the illustrated embodiment, three chuck tables 20 are arranged on the turntable 15 so as to be rotatable in a horizontal plane with a phase angle of 120 degrees. As shown in FIG. 2, the chuck table 20 includes a disk-shaped base 21 and a suction holding chuck 22 formed in a disk shape by a porous ceramic material, and a workpiece to be processed placed on the suction holding chuck 22. The object is sucked and held by operating a suction means (not shown). The chuck table 20 configured as described above is rotated in a direction indicated by an arrow 20a by a rotation driving mechanism (not shown) as shown in FIG. The three chuck tables 20 arranged on the turntable 15 are provided with a workpiece loading / unloading area A, a rough grinding machining area B, a finish grinding machining area C, and a workpiece by appropriately rotating the turntable 15. It is sequentially moved to the loading / unloading area A.

  The illustrated grinding apparatus includes a first cassette 31 that is disposed on one side with respect to a workpiece loading / unloading area A and stocks a semiconductor wafer that is a workpiece before grinding, and a workpiece loading / unloading. A second cassette 32 that is disposed on the other side with respect to the area A and stocks the semiconductor wafer that is a workpiece after grinding, and between the first cassette 31 and the workpiece loading / unloading area A. Centering means 33 for centering the workpiece to be disposed, spinner cleaning means 34 disposed between the workpiece loading / unloading area A and the second cassette 32, and the first cassette 31 Workpiece transport means 35 for transporting the semiconductor wafer, which is a work piece stored in the semiconductor wafer, to the centering means 33 and transporting the semiconductor wafer cleaned by the spinner cleaning means 34 to the second cassette 32, and centering hand A workpiece loading means 36 for conveying the semiconductor wafer placed on the center 33 and centered on the chuck table 20 positioned in the workpiece loading / unloading zone A, and positioned in the workpiece loading / unloading zone A A workpiece unloading means 37 for conveying the semiconductor wafer after grinding mounted on the chuck table 20 to the cleaning means 34, and a suction pad unloading path to be described later in the workpiece unloading means 37. A cleaning means 38 for cleaning the workpiece disposed and held on the suction pad is provided.

  The workpiece unloading means 37 includes an L-shaped operating arm 371 and a suction pad 372 attached to the tip of the operating arm 371. The suction pad 372 is connected to suction means (not shown), and sucks and holds the workpiece on the suction surface (lower surface) by operating the suction means. The operating arm 371 is configured to be swingable in a direction indicated by arrows 37a and 37b around the base by an operating mechanism (not shown). That is, as shown in FIG. 2, the suction pad 372 of the workpiece unloading means 37 is moved between the workpiece loading / unloading area A and the spinner cleaning means 34 along the unloading path indicated by a one-dotted line. .

  Next, the cleaning means 38 will be described with reference to FIG. The cleaning means 38 in the illustrated embodiment is capable of forward / reverse rotation by rotationally driving a support frame 381, a cleaning roller 382 rotatably supported by the support frame 381, and a rotating shaft 382a of the cleaning roller 382. And a cleaning water jet nozzle 384 and 384 disposed on both sides of the cleaning roller 382 and connected to cleaning water supply means (not shown). The cleaning roller 382 is formed of a sponge material in the illustrated embodiment. As shown in FIG. 2, the cleaning means 38 configured in this way is disposed in the carry-out path indicated by the one-dot chain line of the suction pad 372 constituting the workpiece carry-out means 37.

  Continuing the description based on FIG. 2, the grinding device in the illustrated embodiment is configured such that when the suction pad 372 holds the workpiece and carries it out of the workpiece loading / unloading area A to the spinner cleaning means 34. A detection means 39 is provided for detecting when the central portion of the suction pad 372 reaches the cleaning roller 382. In addition, the grinding apparatus includes a control unit 40 that controls the rotation direction of the electric motor 383 constituting the cleaning unit 38 based on a detection signal from the detection unit 39.

The grinding apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
Here, a semiconductor wafer as a workpiece to be ground by the grinding apparatus will be described with reference to FIG. A semiconductor wafer 50 shown in FIG. 4A is made of, for example, a silicon wafer having a thickness of 600 μm, and a plurality of streets 51 are formed in a lattice shape on the surface 50 a and are partitioned by the plurality of streets 51. Circuits 52 are formed in a plurality of regions. A protective member 60 made of polyvinyl chloride or the like is attached to the surface 50a of the semiconductor wafer 50 thus configured, as shown in FIG. 4 (b). A plurality of semiconductor wafers 50 having protective members attached to the front surface are accommodated in the first cassette 31 with the back surface 50b facing upward.

  The semiconductor wafer 50, which is a workpiece before grinding, accommodated in the first cassette 31 is conveyed by the vertical movement and advancing / retreating operation of the workpiece conveying means 35, placed on the center alignment 33, and six pins 331. Centered by radial movement towards the center of The semiconductor wafer 50 placed and centered on the centering means 33 is placed on the suction holding chuck 22 of the chuck table 20 positioned in the workpiece loading / unloading area A by the turning operation of the workpiece loading means 36. Placed. Then, a suction means (not shown) is operated to suck and hold the semiconductor wafer 50 on the suction holding chuck 22. Next, the turntable 15 is rotated 120 degrees in the direction indicated by the arrow 15a by a rotation drive mechanism (not shown), and the chuck table 20 on which the semiconductor wafer is placed is positioned in the rough grinding region B.

  When the chuck table 20 holding the semiconductor wafer 50 is positioned in the rough grinding area B, the chuck table 20 is rotated in a direction indicated by an arrow 20a by a rotation driving mechanism (not shown). On the other hand, the grinding wheel 102 of the rough grinding unit 10 is lowered by a predetermined amount by the feed mechanism 11 while being rotated in the direction indicated by the arrow 102a. As a result, rough grinding is performed on the back surface 50 b of the semiconductor wafer 50 on the chuck table 20. During this time, the semiconductor wafer 50 before grinding is placed on the next chuck table 20 positioned in the work carry-in / out area A as described above. Then, the semiconductor wafer 50 is sucked and held on the chuck table 20 by operating a suction means (not shown). Next, the turntable 15 is rotated 120 degrees in the direction indicated by the arrow 15a, the chuck table 20 holding the semiconductor wafer 50 subjected to rough grinding is positioned in the finish grinding area C, and the semiconductor before grinding is processed. The chuck table 20 holding the wafer 50 is positioned in the rough grinding area B.

  In this manner, the rough grinding unit 10 performs rough grinding on the back surface 50b of the semiconductor wafer 50 before rough grinding held on the chuck table 20 positioned in the rough grinding region B, and finish grinding. The finish grinding unit 12 performs finish grinding on the back surface 50b of the semiconductor wafer 50 placed on the chuck table 20 positioned in the region C and subjected to rough grinding. Next, the turntable 15 is rotated 120 degrees in the direction indicated by the arrow 15a, and the chuck table 20 holding the finish-ground semiconductor wafer 50 is positioned in the workpiece loading / unloading area A. The chuck table 20 holding the semiconductor wafer 50 subjected to rough grinding in the rough grinding region B is held in the finish grinding region C, and the chuck holding the semiconductor wafer 50 before grinding in the workpiece loading / unloading region A. The table 20 is moved to the rough grinding area B, respectively.

  The chuck table 20 that has returned to the workpiece loading / unloading zone A via the rough grinding zone B and the finish grinding zone C releases the suction holding of the semiconductor wafer 50 that has been finish ground here. Then, the finish-ground semiconductor wafer 50 on the chuck table 20 positioned in the workpiece loading / unloading area A is sucked and held on the suction surface (lower surface) of the suction pad 372 constituting the workpiece unloading means 37. Then, it is carried out toward the spinner cleaning means 34. In this unloading process, the surface (lower surface) of the protective member 60 adhered to the surface 50a (lower surface) of the semiconductor wafer 50 sucked and held by the suction pad 372 is the cleaning means disposed in the unloading path of the suction pad 372 It is cleaned by passing through 38.

A cleaning process of the protection member 60 will be described.
When the suction pad 372 that sucks and holds the semiconductor wafer 50 starts to move in the direction indicated by the arrow 37a in FIG. 1 (the direction of unloading from the workpiece loading / unloading area A to the spinner cleaning means 34), the cleaning of the cleaning means 38 is performed. Line clean water is ejected from the water ejection nozzles 384 and 384 (see FIG. 3), and as shown in FIG. 5A, the electric motor 383 is driven to rotate forward, and the cleaning roller 382 is driven to rotate in the direction indicated by the arrow 382a. ing. The rotation direction of the cleaning roller 382 is set to be forward with the moving direction (arrow 37a) of the suction pad 372 at a position facing the suction pad 372 as shown in FIG. For this reason, the outer periphery of the protective member 60 adhered to the surface 50a (lower surface) of the semiconductor wafer 50 is not peeled off when it starts to contact the cleaning roller 382. When the central portion of the suction pad 372 that sucks and holds the semiconductor wafer 50 reaches the cleaning roller 382 as shown in FIG. 5B, the detection means 39 shown in FIG. Send detection signal. When the detection signal from the detection means 39 is input, the control means 40 drives the electric motor 383 of the cleaning means 38 in the reverse direction. Accordingly, the cleaning roller 382 is driven to rotate in the direction indicated by the arrow 382b as shown in FIG. As a result, the rotation direction of the cleaning roller 382 is opposite to the moving direction (arrow 37a) of the suction pad 372 at a position facing the suction pad 372. In this state, when the semiconductor wafer 50 sucked and held by the suction pad 372 moves in the direction indicated by the arrow 37a, the rotation direction of the cleaning roller 382 is changed even when passing through the cleaning roller 382 as shown in FIG. Since the suction pad 372 moves in the opposite direction (arrow 37a), the outer periphery on the passing side of the protective member 60 attached to the surface 50a (lower surface) of the semiconductor wafer 50 does not peel off. In this way, the semiconductor wafer 50 sucked and held by the suction pad 372 passes through the cleaning roller 382 and thereby adheres to the surface (lower surface) of the protective member 60 adhered to the surface 50a (lower surface) of the semiconductor wafer 50. The grinding scraps that are being removed are removed. As described above, the semiconductor wafer 50 that has passed through the cleaning roller 382 is conveyed to the spinner cleaning means 34.

  The semiconductor wafer 40 transported to the spinner cleaning means 34 is spin-dried while cleaning and removing the grinding debris adhering to the back surface 50a (grinding surface) and side surfaces. The semiconductor wafer 50 thus cleaned and spin-dried is transported and stored in the second cassette 32 by the workpiece transport means 35.

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, as a detecting means for detecting when the central portion of the suction pad 372 reaches the cleaning roller 382, the suction pad 372 is rotated by a predetermined angle in the direction in which the suction pad 372 is carried out from the work-in / out area A to the spinner cleaning means 34. Means for detecting this by the number of rotations of a drive motor of an operating mechanism (not shown) may be used.

The perspective view of the grinding device comprised by this invention. Explanatory drawing which shows the arrangement | positioning relationship of the movement path | route of the workpiece delivery mechanism with which the grinding apparatus shown in FIG. 1 is equipped, and the washing | cleaning mechanism. The perspective view of the washing | cleaning mechanism with which the grinding apparatus shown in FIG. 1 is equipped. The perspective view of the semiconductor wafer as a workpiece ground by the grinding apparatus shown in FIG. Explanatory drawing which shows the washing | cleaning process by the washing | cleaning roller which comprises the washing | cleaning mechanism with which the grinding apparatus shown in FIG. 1 is equipped.

Explanation of symbols

2: Device housing 4: Stationary support plate 4
6: Guide rail 8: Guide rail 10: Rough grinding unit 12: Finish grinding unit 13: Feed mechanism 15: Turntable 20: Chuck table 31: First cassette 32: Second cassette 33: Workpiece placement section 34: Cleaning means 35: Workpiece conveying means 36: Workpiece carrying means 37: Workpiece carrying means 371: Actuating arm 372: Suction pad 38: Cleaning mechanism 382: Cleaning roller 383: Electric motor 384: Cleaning water jetting Nozzle 39: Detection means 40: Control means 50: Semiconductor wafer (workpiece)
60: Protection member

Claims (1)

A workpiece comprising a chuck table for holding a workpiece, a grinding means for grinding the workpiece held on the chuck table, and a suction pad for sucking and holding the workpiece ground on the chuck table In a grinding apparatus comprising: an object unloading means; and a cleaning means that is disposed in an unloading path of the suction pad and cleans a workpiece sucked and held by the suction pad.
The cleaning means includes a cylindrical cleaning roller, and an electric motor capable of normal rotation and reverse rotation for rotationally driving the cleaning roller.
Detecting means for detecting a time point when the central portion of the suction pad reaches the cleaning roller;
Control means for controlling the rotation direction of the electric motor based on a detection signal from the detection means,
The control means includes the electric motor so that the rotation direction of the cleaning roller is forward with the moving direction of the suction pad at a position facing the suction pad until the center of the suction pad reaches the cleaning roller. The electric motor so that when the central portion of the suction pad reaches the cleaning roller, the rotation direction of the cleaning roller is opposite to the moving direction of the suction pad at a position facing the suction pad. Drive in reverse,
A grinding apparatus characterized by that.

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