JP4488729B2 - Thickness measuring device and grinding device - Google Patents

Description

  The present invention relates to an apparatus for measuring the thickness of a plate-like object and a grinding apparatus incorporating the apparatus.

  For example, when the surface of a plate-like object such as a semiconductor wafer is to be formed to a desired thickness, the plate-like object is held on the chuck table and a rotating grinding wheel is brought into contact with the exposed surface of the plate-like object. Grind. In general, the thickness of the plate-like object being ground is measured using a stylus-type height gauge, and the grinding is generally terminated when the measured value matches the desired thickness value.

JP 2000-006018 A

  However, the height gauge is prone to failure, and if a failure occurs, it becomes impossible to accurately recognize the thickness of the plate-like material, so that the plate-like material cannot be finished to a desired thickness. Therefore, in order to always obtain the desired thickness for the plate-like material, the plate-like material after grinding is taken out periodically or randomly, and the thickness of the plate-like material is measured by another means to measure the reliability of the height gauge. There is a problem that an extra step of confirming is required, and productivity is lowered.

  Therefore, a problem to be solved by the present invention is to make it possible to efficiently measure the thickness in various processes related to a plate-like object.

The present invention relates to a chuck table for holding a plate-like object, a grinding means for grinding the plate-like object held on the chuck table, a cleaning means for cleaning the plate-like object after grinding, and a chuck for the plate-like object. The present invention relates to a grinding apparatus including at least a conveying unit that conveys from a table to a cleaning unit, and the cleaning unit is a cleaning unit that supports a plate-like object, and cleaning that supplies cleaning water to the plate-like object supported by the support table. A water supply nozzle, and the conveying means moves the holding pad from the chuck table to the support table and presses the plate-like object held by the holding pad against the support table. And a holding portion when the holding surface of the holding pad is brought into close contact with the supporting surface of the support table in a state where the plate-like object is not held by the holding pad of the conveying means. The vertical position of the surface is memorized, and the stored position when the plate-like object is pressed against the support surface of the support table while holding the plate-like object on the holding surface of the holding pad. Measuring means for determining the difference from the vertical position of the surface as the thickness of the plate-like object is disposed adjacent to the support table.

In the grinding apparatus according to the present invention, when the holding surface of the holding pad is brought into close contact with the supporting surface of the supporting table of the cleaning means in a state where the plate-like object is not held by the holding pad of the conveying means, The position is memorized, and the memorized vertical position of the holding surface and the vertical direction of the holding surface when the plate-like object is pressed against the support surface of the support table in a state where the plate-like object is held on the holding surface of the holding pad. Since the measuring means for obtaining the difference from the position as the thickness of the plate-like object is disposed adjacent to the support table, the thickness of the plate-like object can be accurately recognized. In addition, the thickness of the plate after grinding can be measured without going through extra steps, and it is also possible to check whether there is an error in the measurement of the thickness of the plate during grinding. It is.

  A thickness measuring apparatus 1 shown in FIG. 1 includes a support table 2 that holds a plate-like object, a conveying means 3 that holds and conveys the plate-like object, and a measuring means 4 that measures the thickness of the plate-like object. The

  The support table 2 has a support surface 20 formed of a porous member such as porous ceramics, and can hold a plate-like object by a suction force or the like acting on the support surface 20.

  The transport means 3 includes a holding pad 30 that holds a plate-like object on the holding surface 300, and an arm portion 31 that supports the holding pad 30 and rotates or moves up and down. A contact terminal 301 extending in the horizontal direction is fixed to a side portion of the holding pad 30. A buffer member such as a spring is disposed between the arm portion 31 and the holding pad 30 in order to reduce the impact at the time of collision.

  The measuring unit 4 measures the distance between the holding surface 300 of the holding pad 30 and the support surface 20 in a state where the plate-like object held by the holding pad 30 of the transport unit 3 is pressed against the support surface 20 of the support table 2. A measuring rod 40 that has a function and moves forward and backward in the up-and-down direction of the holding pad 30; a main body portion 41 that holds the measuring rod 40 so as to be movable forward and backward; and measures the position of the measuring rod 40; The contact-type measuring instrument includes a storage unit 42 that stores 40 positions and a calculation unit 43 that calculates the thickness of the plate-like object based on the stored contents of the storage unit 42. The measuring rod 40 is located below the contact terminal 301, contacts the contact terminal 301, and moves up and down according to the position of the contact terminal 301. As the measuring means 4, for example, a length measuring device provided by HEIDENHAIN Co., Ltd. can be used.

  When measuring the thickness of the plate-like object held on the holding pad 30 of the conveying means 3, first, as shown in FIG. 2, in a state where the plate-like object is not held on the holding pad 30 of the conveying means 3, The holding surface 300 of the holding pad 30 is brought into close contact with the support surface 20 of the support table 2, and the vertical position Z1 of the measuring rod 40 at that time is measured by the main body 41 and stored in the storage unit 42.

  Next, as shown in FIG. 3, the plate-like object 7 is held on the holding surface 300 of the holding pad 30, and the plate-like object 7 is pressed against the support surface 20 of the support table 2. Then, the vertical position Z2 of the measuring rod 40 at that time is measured by the main body 41 and stored in the storage unit 42.

  The calculation unit 43 reads the values of Z1 and Z2 stored in the storage unit 42, and can calculate the thickness of the plate-like object 7 by calculating (Z1-Z2). Thus, since the thickness can be obtained in a state where the surface of the plate-like object is pressed against the support table 2 by the holding pad 30, the plate-like object is not damaged.

  Note that the contact terminal 301 may not necessarily be required depending on the size and shape of the support table 2 and the holding pad 30, but the distance from the measuring means 4 can be adjusted by adjusting the size and shape of the contact terminal. Thus, the degree of freedom of the installation position of the measuring means 4 with respect to the processing apparatus is increased.

  As an apparatus on which the thickness measuring apparatus 1 is mounted, for example, there is a grinding apparatus 5 shown in FIG. The grinding device 5 is a device for grinding a surface of a plate-like object to have a desired thickness, and cassettes 500 and 501 for accommodating the plate-like object 7 and carrying out or cassettes of the plate-like object 7 from the cassette 500. A carry-in / out means 51 for carrying the plate-like object 7 into and 501, an alignment table 52 for aligning the plate-like object, a first conveying means 53 and a second conveying means 54 for conveying the plate-like object. And four chuck tables 550, 551, 552, and 553 for holding the plate-like object 7, a turntable 56 that supports these chuck tables in a rotatable manner, and can also rotate itself, and is held by each chuck table. It has the 1st grinding means 57 and the 2nd grinding means 58 which grind a plate-shaped object, and the washing | cleaning means 59 which wash | cleans the plate-shaped object after grinding.

The first grinding means 57 and the second grinding means 58 can be raised and lowered with respect to the standing wall portion 60. A pair of first guide rails 61 and second guide rails 62 are disposed on one surface of the wall portion 60 in the vertical direction. The first guide rails 61 support the first grinding means 57. The first support portion 63 is slidably engaged, and the second guide rail 62 is slidably engaged with the second support portion 64 that supports the second grinding means 58. The first grinding means 57 moves up and down as the support portion 63 moves up and down by driving the pulse motor 65, and the second grinding means 58 moves up and down as the support portion 64 moves up and down by driving the pulse motor 66. It is the composition to do. The vertical positions of the first grinding means 57 and the second grinding means 58 can be accurately recognized based on the number of pulses supplied to the pulse motors 65 and 66.

  The first grinding means 57 has a configuration in which a grinding wheel 572 is attached to the lower end of a spindle 570 having a vertical axis through a mounter 571, and a rough grinding wheel 573 is fixed to the lower surface of the grinding wheel 572. Thus, the coarse grinding wheel 573 rotates with the rotation of the spindle 570. On the other hand, the second grinding means 58 has a configuration in which a grinding wheel 582 is attached to a lower end of a spindle 580 having a vertical axis through a mounter 581 and a finish grinding wheel 583 is fixed to the lower surface of the grinding wheel 582. Thus, the finish grinding wheel 583 rotates with the rotation of the spindle 580.

  The plate-like object 7 before grinding is stored in a plurality of stages in the cassette 500 and is carried out one by one by the carrying-in / out means 51 and placed on the alignment table 52. Then, after the plate-like object 7 is aligned at a fixed position, the plate-like object 7 is adsorbed by the first conveying means 53 and the first conveying means 53 pivots, so that the plate-like object 7 is placed on the chuck table 550. Is placed and held.

  Next, the turntable 56 is rotated by a required angle (90 degrees in this embodiment), and the plate-like object 7 is positioned immediately below the first grinding means 57. At this time, the chuck table 551 is automatically positioned at the position where the chuck table 550 is located before the turntable 56 rotates.

  Then, the first grinding means 57 descends while the rough grinding wheel 573 rotates, so that the rough grinding wheel 573 comes into contact with the surface of the plate-like object 7 and the surface is rough ground. Next, the turntable 56 is rotated by a required angle so that the plate-like object 7 is positioned immediately below the second grinding means 58, and the second grinding means 58 is lowered while the finish grinding wheel 583 is rotated, thereby completing the finish. The grinding wheel 583 comes into contact with the surface after the rough grinding of the plate-like object 7 and the surface is finish-ground, so that the plate-like object 7 is formed to a desired thickness. Whether or not the plate-like object 7 is formed to a desired thickness is determined by recognizing the vertical position of the second grinding means 58 from the number of pulses supplied to the pulse motor 66 that drives the second grinding means 58. Can be sought.

  After finishing grinding, the turntable 56 is rotated by a required angle so that the plate-like object 7 is positioned in the vicinity of the cleaning means 59. Then, the plate-like object 7 is conveyed to the cleaning means 59 by the second conveying means 54.

  As shown in FIG. 5, the transport means 3 shown in FIG. 1 can be used as the second transport means 54. A flow passage 540 through which cleaning water or suction air used for cleaning the holding pad 30 circulates is formed inside the second transport means 54, and this flow passage 540 is provided via valves 541 and 542. Are connected to a cleaning water supply source 543 and a suction source 544, respectively.

  On the other hand, the cleaning means 59 includes a spinner table 590 that supports a plate-like object to be cleaned, and a cleaning water supply nozzle 591 that supplies cleaning water to the plate-like object supported by the spinner table 590. As the spinner table 590, The support table 2 shown in FIG. 1 can be used. 1 is disposed in the vicinity of the spinner table 590, and the spinner table 590, the second transport means 54, and the measurement means 4 constitute the thickness measuring apparatus 1.

  Although not shown, the cleaning means 59 is provided with a shutter for preventing the cleaning water from splashing around during cleaning, and the shutter is lowered so that the periphery of the spinner table 59 Cleaning is performed in a state of being sealed by the shutter. Therefore, it is preferable that the measuring means 4 is disposed outside the shutter.

  Before the ground plate 7 is transported to the spinner table 590, as shown in FIG. 6, the holding pad constituting the second transport means 54 in a state where the spinner table 590 does not support the plate. 30 holding surfaces 300 are brought into close contact with the support surface 20 of the spinner table 590. At this time, since the contact terminal 301 pushes the measurement rod 40 downward, the position of the measurement rod 40 at that time is measured in advance in the main body 41 and the position is stored in the storage unit 42 as the origin. The step of storing the origin may be performed once.

  The ground plate-like object 7 is adsorbed by the holding pad 30 that constitutes the second conveying means 54, and is lowered from the chuck table by the arm portion 31 after being positioned directly below the spinner table 590, as shown in FIG. Further, the plate-like object 7 is held by the holding pad 30 while being pressed against the support surface 20 of the spinner table 590. At this time, since the contact terminal 301 pushes the measurement rod 40 downward, the position of the measurement rod 40 at that time is measured in the main body 41 and the position is stored in the storage unit 42.

  As shown in FIG. 6, when the holding pad 30 is brought into close contact with the support surface 20 of the spinner table 590 without the plate-like object, and when the plate-like object 7 is held by the holding pad 20, Since the position of the measuring rod 40 differs by the thickness of the plate-like object 7 when pressed, if the difference between the two positions of the measuring rod stored in the storage unit 42 is calculated by the calculating unit 43, the plate The thickness of the object 7 can be recognized. When the thickness of the plate-like object 7 obtained based on the number of pulses supplied to the pulse motor 66 at the end of finish grinding is compared with the thickness of the plate-like object 7 obtained in the calculation unit 43, the values do not match. Therefore, it can be determined that an error has occurred in the second grinding means 58.

  Since the second conveying means 54 is also a means for conveying the plate-like object 7 from each chuck table to the cleaning means 59, the conveyance and the measurement of the thickness of the plate-like object 7 are continuously performed without passing through extra steps. And can be done efficiently.

  Further, when a height gauge is disposed in the vicinity of the turntable 56 and the thickness of the plate-like object 7 being ground is measured with the height gauge, the measurement result by the thickness measuring device 1 is collated with the result measured with the height gauge after grinding. If the thickness values do not match, it can be determined that the height gauge is defective.

  In the grinding device 5 shown in FIG. 4, the thickness measuring device 1 is configured by the second transporting unit 54, the support table 590 of the cleaning unit 59, and the measuring unit 4, but the transporting unit and the support that configure the measuring device 1. The table may be provided separately from the second transport unit 54 and the support table 590. Moreover, the thickness measuring apparatus 1 can also be mounted in processing apparatuses other than a grinding apparatus.

  The present invention can be used for various processes that require accurate recognition of the thickness of a plate-like object.

It is a perspective view which shows an example of a thickness measuring apparatus. It is a front view which shows a mode that the position of the measuring rod in a state without a plate-shaped object is measured. It is a front view which shows a mode that the position of the measuring rod in a state with a plate-shaped object is measured. It is a perspective view which shows an example of a grinding device. It is sectional drawing which shows the structure of the thickness measuring apparatus in a grinding device. It is a front view which shows a mode that the position of the measuring rod in a state without a plate-shaped object is measured in a grinding device. It is a front view which shows a mode that the position of the measurement rod in a state with a plate-shaped object is measured in a grinding device.

1: Measuring device 2: Support table 20: Support surface 3: Conveying means 30: Holding pad 300: Holding surface 301: Contact terminal 31: Arm part 4: Measuring means 40: Measuring rod 41: Main body part 42: Storage part 43: Calculation unit 5: Grinding device 500, 501: Cassette 51: Loading / unloading means 52: Positioning table 53: First conveying means 54: Second conveying means 540: Flow path 541, 542: Valve 543: Washing water supply source 544: suction source 550, 551, 552, 553: chuck table 56: turntable 57: first grinding means 570: spindle 571: mounter 572: grinding wheel 573: rough grinding wheel 58: second grinding means 580: spindle 581: Mounter 582: Grinding wheel 583: Grinding wheel 59: Cleaning means 590: Spinner table 591 Cleaning water supply nozzle 60: Wall portion 61: first guide rail 62: second guide rail 63: first support portion 64: second support portion 65, 66: pulse motor

Claims (1)

A chuck table for holding the plate-like object, a grinding means for grinding the plate-like object held on the chuck table, a cleaning means for cleaning the plate-like object after grinding, and the plate-like object from the chuck table A grinding device comprising at least a conveying means for conveying to the cleaning means,
The cleaning means includes a support table that supports a plate-like object, and a cleaning water supply nozzle that supplies cleaning water to the plate-like object supported by the support table,
The conveying means moves the holding pad from the chuck table to the support table and presses the plate-like object held by the holding pad against the support table. It consists of an arm part and
Storing the vertical position of the holding surface when the holding surface of the holding pad is brought into close contact with the support surface of the support table in a state where the plate-like object is not held by the holding pad of the transport means ; The stored vertical position of the holding surface and the vertical direction of the holding surface when the plate-like object is pressed against the supporting surface of the support table in a state where the plate-like object is held on the holding surface of the holding pad. A grinding apparatus in which measuring means for determining a difference from the position as the thickness of the plate-like object is disposed adjacent to the support table.

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