JP2023171983A - Grinding device - Google Patents

Abstract

To provide a grinding device that is configured to render washing of an adsorption surface of a conveying pad unnecessary, by preventing grinding dust or spray including grinding dust from adhering to the adsorption surface.SOLUTION: The grinding device is provided with: a spinner cleaning mechanism (27) that cleans a wafer W suctioned and held by a spinner table (42), with cleaning liquid; a carrying mechanism (36) that makes a carrying pad (38) hold and carry the wafer (W) from the chuck table (43) to the spinner table (42); and a control part (90). When grinding the wafer W held on the chuck table (43) with a grindstone in processing chambers (80 and 81), the control part (90) makes the carrying mechanism (36) move the carrying pad (38) to an upper side of the spinner table (42).SELECTED DRAWING: Figure 1

Description

The present invention relates to a grinding device.

In a grinding apparatus used in semiconductor manufacturing, a wafer is held under suction by a chuck table, and a rotating grinding wheel is brought into contact with the wafer to grind the wafer. At this time, grinding debris is generated. Grinding debris has the problem of causing defects in ground wafers due to scattering around the wafer.

For example, during the grinding process, particles may adhere to the suction surface of a transfer pad that is waiting near the grinding wheel. Then, when a wafer that has been ground is next sucked and held, grinding debris may be present between the suction surface and the wafer, and the wafer may be damaged by the grinding debris.

In the grinding apparatus of Patent Document 1, grinding water is supplied to a wafer held on a chuck table in a processing chamber, and the wafer is ground using an annular grindstone. Machining is performed inside the processing chamber, and water seals are formed at the entrance and exit of the processing chamber to prevent grinding debris or spray containing grinding debris from being discharged outside the processing chamber.

In the grinding device of Patent Document 2, a cleaning unit for cleaning the suction surface is arranged. If grinding debris adheres to the suction surface of the transfer pad, the cleaning unit can wash away the grinding debris and keep the suction surface clean.

Japanese Patent Application Publication No. 2010-094785 Japanese Patent Application Publication No. 2012-076171

In a grinding device used in semiconductor manufacturing, in order to increase manufacturing efficiency, it is necessary to maintain the suction surface of a transfer pad in a clean state using a simpler device configuration and a simpler method.

The present invention has been made in view of the above, and provides a grinding device that prevents grinding debris or spray containing grinding debris from adhering to the suction surface of a transfer pad, thereby eliminating the need for cleaning the suction surface. The purpose is to

A grinding apparatus according to one aspect of the present invention includes a chuck table that holds a wafer on a holding surface, a grinding mechanism that uses a grindstone to grind the wafer held on the holding surface, and a nozzle that supplies water to the wafer and the grindstone. , a processing chamber that accommodates the chuck table, the grindstone, and the nozzle; a moving mechanism that moves the chuck table into and out of the processing chamber in a direction parallel to the holding surface; and a spinner table for suction holding. A grinding apparatus comprising: a spinner cleaning mechanism that cleans the wafer with a cleaning liquid; a transport mechanism that holds and transports the wafer from the chuck table to the spinner table using a transport pad; and a control unit, the control unit While the grindstone is grinding a wafer held on the chuck table in the processing chamber, the transport pad is moved above the spinner table by the transport mechanism.

Furthermore, a cleaning time setting part sets a cleaning time for cleaning the wafer with the spinner cleaning mechanism, and a grinding recipe setting part sets a grinding recipe for grinding the wafer held on the holding surface of the chuck table with the grindstone. , a grinding time calculation unit that calculates a grinding time from the grinding recipe set in the grinding recipe setting unit, and the control unit calculates the grinding time calculated by the grinding time calculation unit and the cleaning time setting unit. It is preferable that when the grinding time is longer than the cleaning time when compared with a set cleaning time, the transport pad is moved to the spinner cleaning mechanism.

According to the grinding device of the present invention, cleaning of the suction surface can be made unnecessary by preventing grinding debris or spray containing grinding debris from adhering to the suction surface of the transport pad.

It is a perspective view showing a grinding device of this embodiment. It is a perspective view of the conveyance pad of the grinding apparatus of this embodiment in the state moved above the spinner table by the conveyance mechanism.

Hereinafter, a grinding device according to the present embodiment will be described with reference to the accompanying drawings. FIG. 1 shows the entire protective member forming apparatus according to this embodiment. FIG. 2 shows a state in which the conveyance pad of the grinding device according to this embodiment is moved above the spinner table by the conveyance mechanism.

The X-axis direction, Y-axis direction, and Z-axis direction shown in each figure are perpendicular to each other. The X-axis direction and the Y-axis direction are substantially horizontal directions, and the Z-axis direction is an up-down direction (vertical direction). In each figure, of the double arrows indicating the X-axis direction, the side marked with the letter X is the left side, and the side without the letter X is the right side. Of the double arrows indicating the Y-axis direction, the side marked with the letter Y is defined as the front, and the side without the letter Y is defined as the rear. Of the double arrows indicating the Z-axis direction, the side marked with the letter Z is defined as the upper side, and the side without the letter Z is defined as the lower side.

As shown in FIG. 1, the grinding apparatus 1 is configured to fully automatically perform a series of operations on the wafer W, including loading processing, rough grinding processing, finish grinding processing, cleaning processing, and unloading processing. . The wafer W is formed into a substantially disk shape, and is carried into the grinding apparatus 1 while being accommodated in a cassette C. The wafer W may be a plate-shaped workpiece to be ground, and may be a semiconductor substrate made of silicon, gallium arsenide, etc., an inorganic material substrate such as ceramic, glass, or sapphire, or a package of a semiconductor product. It may also be a substrate or the like. The back surface (upper surface in FIG. 1) of the wafer W is the surface to be ground, and the protective tape T is attached to the front surface (lower surface in FIG. 1).

A pair of cassettes C containing a plurality of wafers W are placed on the front side of the base 11 of the grinding device 1 . A cassette robot 16 that takes wafers W into and out of the cassettes C is provided behind the pair of cassettes C. A positioning mechanism 21 for positioning the wafer W before processing and a spinner cleaning mechanism 26 for cleaning the processed wafer W are provided diagonally at the rear of the cassette robot 16. Between the positioning mechanism 21 and the spinner cleaning mechanism 26, there are provided a loading mechanism 31 for loading the unprocessed wafer W into the chuck table 42, and a transport mechanism 36 for loading the processed wafer W from the chuck table 42. There is.

The cassette robot 16 is constructed by providing a hand section 18 at the tip of a robot arm 17 consisting of a multi-articulated link. In the cassette robot 16, unprocessed wafers W are transferred from the cassette C to the positioning mechanism 21, and processed wafers W are transferred from the spinner cleaning mechanism 26 to the cassette C. The positioning mechanism 21 is configured by arranging a plurality of positioning pins 23 around the temporary table 22 that can move forward and backward with respect to the center of the temporary table 22. In the positioning mechanism 21, the center of the wafer W is positioned at the center of the temporary table 22 by a plurality of positioning pins 23 abutting against the outer peripheral edge of the wafer W placed on the temporary table 22.

The carry-in mechanism 31 is configured by providing a carry-in pad 33 at the tip of a carry-in arm 32 that is rotatable on the base 11 . In the carry-in mechanism 31, the wafer W is lifted from the temporary table 22 by the carry-in pad 33, and the wafer W is carried into the chuck table 42 by rotating the carry-in pad 33 by the carry-in arm 32. The transport mechanism 36 is configured by providing a transport pad 38 at the tip of a transport arm 37 that is rotatable on the base 11 . In the transport mechanism 36 , the wafer W is suction-held by the transport pad 38 and lifted from the chuck table 42 , and the transport arm 37 rotates the transport pad 38 to transport the wafer W from the chuck table 42 . A suction surface for suctioning and holding the wafer W is formed by a porous plate on the lower surface of the transfer pad 38, and the suction surface is connected to a suction source.

The spinner cleaning mechanism 26 includes a nozzle 28 that sprays cleaning water or dry air toward the spinner table 27, and a cover 29 that covers the spinner cleaning mechanism 26 during cleaning. In the spinner cleaning mechanism 26, a spinner table 27 holds the wafer W. A cover 29 rises from within the base 11 and covers the spinner cleaning mechanism 26. In the spinner cleaning mechanism 26 covered by the cover 29, cleaning water is sprayed from a nozzle to clean the wafer W, and then dry air is blown to dry the wafer W.

Alternatively, the cover 29 covering the spinner cleaning mechanism 26 may be divided into the cassette C side and the moving mechanism 41 side, and the cover on the cassette C side and the cover on the moving mechanism 41 side may be moved up and down individually.

Further, as another form of the spinner cleaning mechanism 26, the spinner table 27 holding the wafer W may be lowered into the base 11 to perform cleaning. In this case, cleaning water is sprayed within the base 11 to clean the wafer W using a spinner, and then dry air is blown to dry the wafer W.

Behind the carry-in mechanism 31 and the transport mechanism 36, a moving mechanism (turntable) 41 is provided in which three chuck tables 42 are rotatably arranged at equal intervals in the circumferential direction. A holding surface 43 is formed on the upper surface of each chuck table 42 to hold the wafer W by suction via a protective tape T.

The moving mechanism 41 rotates intermittently at 120 degree intervals, resulting in a loading/unloading position 45a where wafers W are loaded and unloaded, a rough grinding position 45b facing a rough grinding mechanism (grinding mechanism) 46, and a finishing grinding mechanism (grinding mechanism). The finishing grinding position 45c is positioned opposite to the finishing grinding position 45c. At the rough grinding position 45b, the wafer W is roughly ground to a predetermined thickness by the rough grinding mechanism 50. At the finish grinding position 45c, the wafer W is finish ground by the finish grinding mechanism 55 to the finish thickness. Columns 12 and 13 are erected around the moving mechanism 41.

Above the axis of the moving mechanism 41, in the vicinity of the rough grinding position 45b and the finish grinding position 45c, there are first measuring means 44a for measuring the height of the holding surface of the chuck table 42, and a first measuring means 44a for measuring the height of the upper surface of the wafer W. A second measuring means 44b is provided for measuring. The first measuring means 44a and the second measuring means 44b are both constructed of contact-type height gauges.

A rough grinding chamber 80 and a finish grinding chamber 81 are provided around the moving mechanism 41, covering the rough grinding mechanism 50 and the finish grinding mechanism 55, respectively. Each processing chamber is formed by a box-shaped cover member 82. The cover member 82 is provided with an opening wall 83 that opens so that the chuck table 42 can enter and exit the processing chamber when the moving mechanism 41 rotates. The chuck table 42 is configured to be movable into and out of the processing chamber in a direction parallel to the holding surface 43.

A nozzle (not shown) for supplying water to the wafer W held by the chuck table 42 and the grindstone is provided in each processing chamber. The position of the nozzle that supplies water to the wafer W and the grindstone is not particularly limited, and may be provided anywhere within the processing chamber, or may be configured to be supplied from the grinding wheels 53 and 58 of the grinding mechanism. good.

The top wall 84 of the cover member 82 is provided with a circular opening 85 through which the grinding wheels 53, 58 can be inserted.

A partition plate 46 is provided on the upper surface of the moving mechanism 41 to partition the area where each chuck table is provided. The partition plate 46 is provided to extend in the radial direction from the axial center of the moving mechanism 41, and is formed higher than the height of the chuck table 42.

The upper surface of the partition plate 46 is provided with a groove (not shown), and water is supplied to the groove from a water supply section (not shown) inside the shaft center portion of the moving mechanism 41. With this configuration, a water seal is formed between the rough grinding chamber 80 and the lower surface of the opening wall 83 of the finish grinding chamber 81 due to the surface tension of the water supplied to the groove.

The water seal has the function of partitioning the chuck table 42 located within each processing chamber. Occurs during grinding due to water seals. It is possible to suppress splashes such as grinding debris from entering adjacent processing chambers and scattering outside the processing chamber.

The column 12 is provided with a drive mechanism 61 that moves the rough grinding mechanism 50 up and down. The drive mechanism 61 includes a pair of guide rails 62 arranged in front of the column 12 and parallel to the Z-axis direction, and a motor-driven Z-axis table 63 slidably installed on the pair of guide rails 62. There is. A rough grinding mechanism 50 is supported on the front surface of the Z-axis table 63 via a housing 64. A ball screw 65 is screwed onto the back side of the Z-axis table 63, and a drive motor 66 is connected to one end of the ball screw 65. The ball screw 65 is rotationally driven by the drive motor 66, and the rough grinding mechanism 50 is moved along the guide rail 62 in the Z-axis direction.

Similarly, the column 13 is provided with a drive mechanism 71 that moves the finish grinding mechanism 55 up and down. The drive mechanism 71 includes a pair of guide rails 72 arranged in front of the column 13 and parallel to the Z-axis direction, and a motor-driven Z-axis table 73 slidably installed on the pair of guide rails 72. There is. A finish grinding mechanism 55 is supported on the front surface of the Z-axis table 73 via a housing 74. A ball screw 75 is screwed onto the back side of the Z-axis table 73, and a drive motor 76 is connected to one end of the ball screw 75. The ball screw 75 is rotationally driven by the drive motor 76, and the finish grinding mechanism 55 is moved along the guide rail 72 in the Z-axis direction.

A mount 52 is provided at the lower end of the spindle 51 of the rough grinding mechanism 50, and a grinding wheel 53 for rough grinding in which a plurality of rough grinding wheels (grinding wheels) 50 are arranged in an annular manner is mounted on the lower surface of the mount 52. . The rough grinding wheel 54 is, for example, a diamond wheel made of diamond abrasive grains hardened with a binder such as metal bond or resin bond. Further, a mount 57 is provided at the lower end of the spindle 56 of the finish grinding mechanism 55, and a grinding wheel 58 for finish grinding in which a plurality of finish grinding wheels (grinding wheels) 59 are arranged in an annular manner is mounted on the lower surface of the mount 57. be done. The finishing grinding wheel 59 is composed of abrasive grains having a finer grain size than the rough grinding wheel 54.

When grinding a wafer W with such a grinding apparatus 1, the wafer W is first transferred from the cassette C to the positioning mechanism 21, and the wafer W is centered by the positioning mechanism 21. Next, the wafer W is carried into the loading/unloading position 45a on the chuck table 42 with the surface to be ground, which is the back surface of the wafer W, facing upward and the protective tape T attached to the front surface facing downward, and the wafer W is held by suction. Ru. Then, by rotation of the moving mechanism 41, the wafer W is positioned in the order of the rough grinding position 45b and the finish grinding position 45c.

During rough grinding of the wafer W at the rough grinding position 45b, the wafer W is suction-held by the chuck table 42 using the surface of the protective tape T attached to the wafer W as the surface to be held. In this state, the rough grinding wheel 54 that rotates while rotating the chuck table 42 around the Z-axis is brought into contact with the upper surface of the wafer W, and the upper surface of the wafer W is roughly ground as a surface to be ground. In the final grinding of the wafer W at the final grinding position 45c after the movement mechanism 41 has been rotated, the finishing grinding wheel 59, which rotates while rotating the chuck table 42 around the Z-axis, ) for final grinding.

After the final grinding, the surface of the wafer W to be ground is suctioned and held by the transport pad 38 of the transport mechanism 36, and the wafer W is transported to the spinner cleaning mechanism 26. The wafer W is cleaned by the spinner cleaning mechanism 26, and the wafer W is carried out from the spinner cleaning mechanism 26 to the cassette C.

The grinding device 1 is centrally controlled by a control unit 90 (FIG. 1), and the control unit 90 is composed of a processor that executes various processes, and a storage unit (memory) that stores various parameters, programs, etc. ing. For example, the control unit 90 controls the operation of moving a transport pad 38, which will be described later, above the spinner table 27.

The storage section of the control section 90 includes a cleaning time setting section 91 . The cleaning time setting section 91 stores the cleaning time for cleaning the wafer W by the spinner cleaning mechanism 26.

The storage section of the control section 90 includes a grinding recipe setting section 92. The grinding recipe setting unit 92 stores a grinding recipe for grinding the wafer W held on the holding surface 43 of the chuck table 42 with a grindstone. The grinding recipe sets the wafer thickness of the desired wafer W before grinding, the finished wafer thickness for determining completion of grinding, the rotation speed of the chuck table 42, the feed speed for lowering the grindstone, the rotation speed of the grindstone, etc.

The storage section of the control section 90 includes a grinding time calculation section 93. The grinding time calculation unit 93 calculates the grinding time from the difference (grinding amount) between the wafer thickness before grinding and the finished wafer thickness of the grinding recipe set in the grinding recipe setting unit and the feed rate at which the grinding wheel is lowered.

Next, with reference to FIG. 2, the functions of the grinding device according to this embodiment will be explained. FIG. 2 shows that in the grinding apparatus according to the present embodiment, when the wafer W held on the chuck table 42 in the processing chamber is being ground with a grindstone, the transport pad 38 is moved above the spinner table 27 by the transport mechanism 36. It is a perspective view of the state moved to .

As shown in FIG. 2, in the grinding apparatus according to this embodiment, when a wafer W held on a chuck table 42 is being ground with a grindstone in a processing chamber, a transfer pad 38 is transferred to a spinner table by a transfer mechanism 36. It is moved above 27.

With this configuration, the transport pad 38 can be placed on standby at a distance from the grinding mechanism or the processing chamber. This prevents polishing debris scattered from the grinding mechanism or spray containing polishing debris scattered from the entrance/exit of the processing chamber when the moving mechanism (turntable) 41 is rotated from adhering to the transport pad 38. be able to.

Therefore, the suction surface of the transfer pad 38 can be maintained in a clean state with a simple configuration and a simple method. Furthermore, the cleaning time required by a dedicated unit for cleaning the transport pad 38 can be eliminated, and production efficiency can be improved.

In this embodiment, the operation of moving the transport pad 38 above the spinner table 27 by the transport mechanism 36 will be described.

This operation may be performed at any timing during the grinding process. For example, it may be carried out at a timing before starting the grinding process, or may be carried out during the grinding process.

In the control unit 90, the operation of moving the transport pad 38 above the spinner table 27 is controlled. In the grinding time calculating section 93, the grinding time is calculated from the grinding recipe stored in the grinding recipe setting section 92.

Subsequently, the calculated grinding time is compared with the cleaning time stored in the spinner cleaning time setting section 91. If the control unit 90 determines that the calculated grinding time is longer than the cleaning time set in the cleaning time setting unit 91, the conveyance mechanism 36 rotates on the base 11, and the conveyance pad 38 is moved to the spinner cleaning mechanism. Move above 26.

Alternatively, when the transport pad 38 is waiting above the spinner table 27, air may be jetted out from the suction surface of the transport pad 38 to form an air layer between the suction surface and the upper surface of the spinner table 49. good. This is preferable because the ejected air can more effectively prevent adhesion of polishing debris or spray containing polishing debris.

Alternatively, the cover 29 covering the spinner cleaning mechanism 26 may be divided, and the cover on the cassette C side and the cover on the moving mechanism 41 side may each operate independently.

In this case, when the transport pad 38 is waiting above the spinner table 27, the cover on the moving mechanism 41 side can be raised to prevent grinding debris from scattering from the processing chamber side, which is preferable. Furthermore, when the cover on the moving mechanism 41 side is raised, the transport arm 37 collides with the cover, preventing the cover from rising. A groove may also be provided. Further, the cover on the moving mechanism 41 side may be divided so as to be able to rise so as not to collide with the transport arm 37 when the transport pad 38 is placed on standby above the spinner table 27.

After finish grinding in the grinding process, the chuck table 42 after finish grinding moves to the carry-in/out position 45a. The transport pad 38 above the spinner cleaning mechanism 26 is rotated on the base 11 by the transport mechanism 36 . The transfer pad 38 sucks and holds the surface of the wafer W to be ground, and the wafer W is carried out to the spinner cleaning mechanism 26, where the wafer W is cleaned.

Furthermore, in the present embodiment, as shown in FIG. 1, the grinding device 1 has been described as having a configuration including a plurality of grinding mechanisms for the purpose of performing rough grinding and finish grinding, but the present invention is not limited to this configuration. . For example, the configuration may include a single grinding mechanism.

As described above, it is possible to prevent grinding debris or spray containing grinding debris from adhering to the suction surface of the transfer pad, thereby making it unnecessary to clean the suction surface. Thereby, the suction surface of the transfer pad can be maintained in a clean state with a simple configuration and a simple method. Furthermore, the cleaning time required by a dedicated unit for cleaning the transfer pad can be eliminated, and production efficiency can be improved.

1: Grinding device 11: Base 12: Column 13: Column 16: Cassette robot 17: Robot arm 18: Hand part 21: Positioning mechanism 22: Temporary table 23: Positioning pin 26: Spinner cleaning mechanism 27: Spinner table 28: Nozzle 29 : Cover 31 : Carry-in mechanism 32 : Carry-in arm 33 : Carry-in pad 36 : Transport mechanism 37 : Transport arm 38 : Transport pad 41 : Movement mechanism 42 : Chuck table 43 : Holding surface 44a : First measuring means 44b : First Measuring means 45a of 2: Loading/unloading position 45b: Rough grinding position 45c: Finish grinding position 46: Partition plate 50: Rough grinding mechanism 51: Spindle 52: Mount 53: Grinding wheel 54: Rough grinding wheel 55: Finish grinding mechanism 56: Spindle 57 : Mount 58 : Grinding wheel 59 : Finish grinding wheel 61 : Drive mechanism 62 : Guide rail 63 : Z-axis table 64 : Housing 65 : Ball screw 66 : Drive motor 71 : Drive mechanism 72 : Guide rail 73 : Z-axis table 74 : Housing 75 : Ball screw 76 : Drive motor 80 : Rough grinding chamber 81 : Finish grinding chamber 82 : Cover member 83 : Opening wall 84 : Upper wall part 85 : Circular opening part 90 : Control part 91 : Spinner cleaning time setting part 92: Grinding recipe setting section 93: Grinding time calculation section C: Cassette T: Protective tape W: Wafer

Claims (2)

a chuck table that holds the wafer on a holding surface;
a grinding mechanism that uses a grindstone to grind the wafer held on the holding surface;
a nozzle that supplies water to the wafer and the grindstone;
a processing chamber that accommodates the chuck table, the grindstone, and the nozzle;
a moving mechanism that moves the chuck table into and out of the processing chamber in a direction parallel to the holding surface;
a spinner cleaning mechanism that cleans the wafer suctioned and held by the spinner table with cleaning liquid;
a transport mechanism that holds and transports the wafer from the chuck table to the spinner table using a transport pad;
A grinding device comprising a control unit,
The control unit is a grinding device that moves the transport pad above the spinner table by the transport mechanism when the grindstone is grinding a wafer held on the chuck table in the processing chamber. a cleaning time setting unit that sets a cleaning time for cleaning the wafer with the spinner cleaning mechanism;
a grinding recipe setting unit that sets a grinding recipe for grinding the wafer held on the holding surface of the chuck table with the grindstone;
A grinding time calculation unit that calculates the grinding time from the grinding recipe set in the grinding recipe setting unit,
The control unit compares the grinding time calculated by the grinding time calculation unit with the cleaning time set by the cleaning time setting unit, and when the grinding time is longer than the cleaning time, the control unit moves the transfer pad to the spinner. The grinding device according to claim 1, wherein the grinding device is moved to a cleaning mechanism.

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