JP6687455B2 - Grinding machine - Google Patents

Description

  The present invention relates to a grinding device that grinds a resin layer on a semiconductor wafer.

  BACKGROUND ART As a grinding target of a grinding device, a plate-like work is known in which a columnar post electrode is erected on a wiring layer of a semiconductor wafer and the post electrode is resin-molded. The upper surface of the post electrode is exposed to the outside by grinding the resin layer on the surface of this plate-shaped work.However, when the post electrode is ground together with the resin layer, grinding dust such as metal powder adheres to the grindstone. I will end up. Therefore, a method is known in which the resin layer is ground while the distance from the upper surface of the resin layer of the plate-shaped work to the upper end surface of the post electrode is measured to expose the upper end surface of the post electrode from the upper surface of the resin layer. (See, for example, Patent Documents 1 and 2).

JP, 2014-103140, A JP, 2014-138037, A

  By the way, the distance between the upper surface of the resin layer and the upper end surface of the post electrode is measured by an optical sensor or the like from the optical path length difference between the reflected light from the upper surface of the resin layer and the reflected light from the upper end surface of the post electrode. However, if the resin on the post electrode is ground until it becomes thin, the reflected light from the upper surface of the resin layer cannot be distinguished from the reflected light from the upper end surface of the post electrode, and the resin on the upper end of the post electrode cannot be distinguished. It becomes impossible to measure the thickness. Therefore, there is a problem that the grinding cannot be stopped when the upper end surface of the post electrode is exposed on the upper surface of the resin layer, and the upper end surface of the post electrode is ground by the grinding wheel.

  The present invention has been made in view of the above point, and an object of the present invention is to provide a grinding apparatus that can grind only a resin layer to expose the upper end surface of an electrode.

The grinding apparatus of the present invention is a grinding apparatus that grinds the upper surface of a resin layer of a plate-like work that covers a columnar electrode standing on the upper surface of a semiconductor wafer with a resin to form a resin layer with a grinding wheel. Holding means having a rotating means for rotating a holding table for holding the work; grinding means for rotatably mounting a grinding wheel for grinding the resin layer of the plate-like work held by the holding means; and the grinding means. And a non-contact measuring means for measuring the thickness of the resin ground by the grinding wheel in a non-contact manner. The contact measuring unit includes a light projecting unit that projects measuring light from above the plate-shaped work held by the rotating holding unit, a light receiving unit that receives reflected light reflected by the plate-shaped work, and a light receiving unit that receives the reflected light. While grinding the resin layer with the grinding wheel From the difference in optical path length between the first reflected light reflected by the upper surface of the resin, the second reflected light reflected by the upper end surface of the electrode, and the third reflected light reflected by the upper surface of the semiconductor wafer , The thickness t1 of the resin on the semiconductor wafer, the thickness t2 of the resin on the upper end of the electrode, and the target thickness t3 of the resin on the semiconductor wafer when the thickness t2 of the resin on the upper end of the electrode is zero. A calculating means for calculating a plurality of thickness data including the plurality of thickness data, and a smaller one of the thickness t1 of the resin on the semiconductor wafer and the resin thickness t2 on the upper end of the electrode calculated by the calculating means, whichever is smaller, on the upper end of the electrode. Determining means for determining the thickness t2 of the resin, the thickness t1 of the resin on the semiconductor wafer is measured by the non-contact measuring means , and the resin is ground by the grinding wheel, and further, by the calculating means. Top of the electrode The thickness t2 of the resin on the semiconductor wafer when the zero calculates a target thickness t3 of the resin, after the calculated unloading is on the semiconductor wafer without calculating the thickness t2 of the resin on the upper end of the electrode The resin is ground by the grinding means until the thickness t1 of the resin reaches the target thickness t3.

  According to this configuration, a plurality of light beams measured from the first reflected light reflected on the upper surface of the resin layer, the second reflected light reflected on the upper end surface of the electrode, and the third reflected light reflected on the upper surface of the semiconductor wafer. The smaller thickness data is determined as the thickness of the resin on the upper end of the electrode. Thereby, the thickness of the resin on the semiconductor wafer and the thickness of the resin on the upper end of the electrode can be distinguished from the plurality of thickness data. At this time, since the target thickness of the resin on the semiconductor wafer when the resin thickness on the upper end of the electrode is zero is known, the thickness of the resin on the semiconductor wafer can be measured without measuring the resin thickness on the upper end of the electrode thereafter. It suffices to grind while measuring only. By grinding the resin on the semiconductor wafer so as to approach the target thickness, it is possible to grind only the resin on the upper end of the electrode to expose the upper end surface of the electrode.

  According to the present invention, the target thickness of the resin on the semiconductor wafer when the thickness of the resin on the upper end of the electrode is zero is determined from the thickness of the resin on the semiconductor wafer and the thickness of the resin on the upper end of the electrode. Therefore, by bringing the thickness of the resin on the semiconductor wafer close to the target thickness, it is possible to grind only the resin layer and expose the upper end surface of the electrode.

It is a perspective view of the grinding device of the present embodiment. It is a figure which shows an example of the measurement process by the non-contact measuring means of a comparative example. It is a figure which shows an example of the measurement process by the non-contact measuring means of this Embodiment. It is a figure which shows an example of the grinding operation by the grinding device of this Embodiment.

  Hereinafter, the grinding device of the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of the grinding apparatus of this embodiment. It should be noted that the grinding apparatus of the present embodiment is not limited to the apparatus configuration dedicated to grinding as shown in FIG. 1, and for example, a series of processing such as grinding, polishing, and cleaning is carried out automatically. It may be incorporated in a fully automatic processing device.

  As shown in FIG. 1, the grinding device 1 is configured to grind a plate-shaped work W held by a holding means 20 using a grinding wheel 45 in which a large number of grinding wheels 46 are arranged in an annular shape. In the plate-shaped work W, the resin layer 75 is laminated on the semiconductor wafer 70 by covering the columnar electrodes 72 (see FIG. 3A) standing on the wiring layer 71 (see FIG. 3A) on the semiconductor wafer 70 with resin. Is configured. The plate-like work W is held by the holding means 20 via the protective tape T, and the upper surface of the resin layer 75 is ground to expose the columnar electrodes 72 from the upper surface of the resin layer 75 (see FIG. 3C). The semiconductor wafer is not limited to a silicon wafer, and may be a wafer such as gallium arsenide or silicon carbide.

  A rectangular opening extending in the X-axis direction is formed on the upper surface of the base 10 of the grinding apparatus 1. The opening is covered with a movable plate 11 movable along with the holding means 20 and a bellows-like waterproof cover 12. ing. Below the waterproof cover 12, ball screw type advancing / retreating means (not shown) for moving the holding means 20 in the X-axis direction is provided. The holding means 20 is configured to rotate the holding table 21 by the rotating means 22 while holding the plate-shaped work W on the holding table 21. On the upper surface of the holding table 21, a holding surface 23 for suction-holding the plate-shaped work W is formed by a porous material.

  The column 13 on the base 10 is provided with a grinding feed means 30 for feeding the grinding means 40 toward and away from the holding means 20 (Z-axis direction). The grinding feed means 30 has a pair of guide rails 31 arranged in the column 13 and parallel to the Z-axis direction, and a motor-driven Z-axis table 32 slidably installed on the pair of guide rails 31. . Not-shown nuts are formed on the back side of the Z-axis table 32, and ball screws 33 are screwed into these nuts. The grinding motor 40 is moved along the guide rail 31 in the Z-axis direction by rotationally driving the ball screw 33 by the drive motor 34 connected to one end of the ball screw 33.

  The grinding means 40 is attached to the front surface of the Z-axis table 32 via a housing 41, and has a mount 43 provided at the lower end of a cylindrical spindle 42. A flange 44 is provided on the spindle 42, and the grinding means 40 is supported by the housing 41 via the flange 44. On the lower surface of the mount 43, a grinding wheel 45 having a plurality of grinding wheels 46 annularly arranged is rotatably mounted. As each of the grinding wheels 46, for example, a vitrified grinding wheel in which a large number of abrasive grains are bonded by vitrified bonds is used. The vitrified grindstone makes it possible to reduce the adhesion of resin to the ground surface.

  Near the holding table 21, contact measuring means 49 for measuring the height of the holding surface 23 of the holding table 21 and non-contact measuring means 50 for measuring the resin thickness of the plate-shaped work W in a non-contact manner are provided. ing. The contact measuring means 49 is a so-called height gauge, and contacts the holding surface 23 of the holding table 21 with a tracing stylus to measure the height of the holding surface 23 that serves as a reference during grinding. The non-contact measuring means 50 is a so-called spectroscopic interferometer, which projects measurement light onto the plate-like work W, and the thickness of the resin layer 75 (see FIG. 3) from the reflected light reflected by the plate-like work W. Is being measured. The details of the non-contact measuring means 50 will be described later.

  In addition, the grinding device 1 is provided with a control means 60 that integrally controls each part of the device. Further, the non-contact measuring means 50 is provided with a calculating means 56 and a judging means 57 described later. The control unit 60, the calculation unit 56, and the determination unit 57 are configured by a processor that executes various processes, a memory, and the like. The memory is configured by one or a plurality of storage media such as a ROM (Read Only Memory) and a RAM (Random Access Memory) according to the application. By controlling the grinding feed amount of the grinding means 40 with high accuracy by the control means 60, only the resin layer 75 of the plate-shaped work W is ground and the columnar electrode 72 (see FIG. ) Is exposed.

  By the way, when exposing the columnar electrode from the resin layer, it is common to grind while measuring the thickness of the resin on the upper end of the electrode, but it is difficult to grind only the resin by such a method. . Here, with reference to FIG. 2, a general measurement process using the non-contact measuring means will be described. FIG. 2 is a diagram showing an example of a measurement process performed by the non-contact measuring means of the comparative example.

  As shown in FIG. 2A, at the start of grinding the plate-shaped workpiece W, the measurement light from the non-contact measuring means 50 does not pass through the resin layer 75, and only the first reflected light R1 reflected by the upper surface 76 of the resin layer 75 is generated. The light is received by the non-contact measuring means 50. This is because the distance from the upper surface 76 of the resin layer 75 to the upper end surface 73 of the columnar electrode 72 is large, and the resin on the upper end of the electrode 72 is sufficiently thick so that it is not contacted by the filler or the like contained in the resin layer 75. This is because the measuring light projected from the measuring means 50 is scattered. Therefore, immediately after the start of grinding, the resin layer 75 of the plate-shaped work W is ground without measuring the thickness of the resin on the upper end of the electrode 72.

  Subsequently, as shown in FIG. 2B, when the resin layer 75 is ground and the distance from the upper surface 76 of the resin layer 75 to the upper end surface 73 of the columnar electrode 72 becomes shorter, the first light reflected by the upper surface 76 of the resin layer 75. In addition to the reflected light R1 of the above, the second reflected light R2 reflected by the upper end surface 73 of the electrode 72 is received by the non-contact measuring means 50. At this time, from the difference in optical path length between the first reflected light R1 reflected by the upper surface 76 of the resin layer 75 and the second reflected light R2 reflected by the upper end surface 73 of the electrode 72, the resin on the upper end of the electrode 72 is The thickness t is measured. Therefore, in the middle of grinding, the resin layer 75 of the plate-shaped work W is ground while measuring the thickness t of the resin on the upper end of the electrode 72.

  However, as shown in FIG. 2C, when the distance from the upper surface 76 of the resin layer 75 to the upper end surface 73 of the columnar electrode 72 becomes further shorter, the non-contact measuring means 50 reflects the first light reflected by the upper surface 76 of the resin layer 75. The reflected light R1 and the second reflected light R2 reflected by the upper end surface 73 of the electrode 72 cannot be distinguished. Further, a spectroscopic interferometer is used as the non-contact measuring means 50 for measuring the thickness of the resin, but a normal spectroscopic interferometer cannot measure a minute thickness. Therefore, immediately before the end of grinding, the thickness of the resin on the upper end of the electrode 72 cannot be measured, and the resin layer 75 of the plate-shaped work W may be ground too much.

  Therefore, in the present embodiment, the resin thickness t1 on the semiconductor wafer 70 (see FIG. 3B) and the resin thickness t2 on the upper ends of the columnar electrodes 72 (see FIG. 3B) are obtained during grinding, and at this point of time. The target thickness t3 (see FIG. 3B) of the resin on the semiconductor wafer 70 when the resin thickness on the upper end of the electrode 72 is zero is calculated. Accordingly, after the calculation of the target thickness t3, the resin layer 75 is ground so that the resin thickness t1 of the semiconductor wafer 70 approaches the target thickness t3 without measuring the resin thickness t2 on the upper end of the electrode 72. The upper end surface 73 of the electrode 72 can be exposed by grinding only the surface.

  Hereinafter, with reference to FIG. 3, a measurement process using the non-contact measuring means of the present embodiment will be described. FIG. 3 is a diagram showing an example of measurement processing by the non-contact measuring means of the present embodiment.

  As shown in FIG. 3A, in the non-contact measuring means 50, when the measuring light is emitted from the light projecting portion 51, a part of the measuring light is reflected on the reference surface (not shown) in the sensor head 53 via the half mirror 52. Is reflected and the remaining measurement light transmitted through the reference surface is projected from above the plate-like work W. The reflected light reflected by the plate-shaped work W passes through the reference surface in the sensor head 53, is separated by the diffraction grating 54, and is received by the light receiving unit 55. The distance (optical path length) from the sensor head 53 to the reflection position of the plate-shaped work W is measured based on the interference light intensity of the reflected light from the reference surface and the reflected light from the plate-shaped work W at this time.

  At the start of grinding of the plate-shaped work W, the measurement light from the light projecting section 51 of the non-contact measuring means 50 does not pass through the resin layer 75 of the plate-shaped work W as described above, and is reflected by the upper surface 76 of the resin layer 75. Only the first reflected light R1 is received by the light receiving unit 55. Therefore, only the distance from the sensor head 53 to the upper surface 76 of the resin layer 75 is measured based on the first reflected light R1, and the thickness of the resin on the upper ends of the columnar electrodes 72 is also measured on the semiconductor wafer 70. Thickness is not measured either. Therefore, immediately after the start of grinding, the resin layer 75 of the plate-shaped work W is ground without measuring the thickness of the resin layer 75 of the plate-shaped work W.

  As shown in FIG. 3B, when the resin layer 75 of the plate-shaped work W is ground, the distance from the upper surface 76 of the resin layer 75 to the upper end surface 73 of the columnar electrode 72 is reduced, and at the same time, the upper surface 76 of the resin layer 75. To the upper surface 77 of the semiconductor wafer 70. Then, the first reflected light R1 reflected by the upper surface 76 of the resin layer 75, the second reflected light R2 reflected by the upper end surface 73 of the electrode 72, and the third reflected light R3 reflected by the upper surface 77 of the semiconductor wafer 70. Is received by the light receiving unit 55 (see FIG. 3A). The light reception result by the light receiving unit 55 is converted into an electric signal and output to the calculating means 56 (see FIG. 3A), and the calculating means 56 calculates the thickness of the resin from the optical path length difference between the first to third reflected lights R1, R2, and R3. Is calculated.

  At this time, the calculating means 56 calculates the thickness t2 of the resin on the upper end of the columnar electrode 72 and the thickness t1 of the resin on the semiconductor wafer 70 from the optical path length difference of the first to third reflected lights R1, R2, R3. A plurality of thickness data including is measured. The resin thickness t2 on the upper end of the electrode 72 is the optical path length difference between the first and second reflected lights R1 and R2, and the resin thickness t1 on the semiconductor wafer 70 is the optical path of the first and third reflected lights R1 and R3. Although there is a difference in length, the calculating means 56 cannot recognize which of the plurality of thickness data the thicknesses t1 and t2 of these resins correspond to. Therefore, the plurality of thickness data are output to the determination means 57 (see FIG. 3A), and the determination means 57 determines that the smaller data of the plurality of thickness data is the resin thickness t2 on the upper end of the electrode 72.

  Thus, the thickness t2 of the resin on the upper end of the columnar electrode 72 and the thickness t1 of the resin on the semiconductor wafer 70 are distinguished from each other based on the plurality of thickness data. From the resin thickness t2 on the upper end of the electrode 72 and the resin thickness t1 on the semiconductor wafer 70 at this time, the resin thickness on the semiconductor wafer 70 when the resin thickness t2 on the upper end of the electrode 72 becomes zero. The target thickness t3 is calculated. As described above, when the second and third reflected lights R2 and R3 are received, the target thickness t3 of the resin on the semiconductor wafer 70 corresponding to the upper end surface 73 of the electrode 72 is calculated, and thus the electrode 72 of the electrode 72 is calculated. It is possible to grind only the resin without measuring the thickness t2 of the resin on the upper end.

  As shown in FIG. 3C, when the target thickness t3 of the resin on the semiconductor wafer 70 is calculated, the control means 60 (see FIG. 3A) grinds the resin thickness t1 on the semiconductor wafer 70 so as to approach the target thickness t3. The feeding means 30 (see FIG. 3A) is controlled. As described above, since the grinding can be performed while measuring only the resin thickness t1 on the semiconductor wafer 70, even if the resin thickness t2 on the upper end of the columnar electrode 72 becomes small, the grinding accuracy is not affected. Therefore, the resin layer 75 can be accurately ground until the resin thickness t1 on the upper end of the electrode 72 becomes zero, and the upper end surface 73 of the electrode 72 is exposed on the upper surface 76 of the resin layer 75 without scraping the electrode 72. Can be made.

  With reference to FIG. 4, a grinding operation by the grinding device of the present embodiment will be described. FIG. 4 is a diagram showing an example of a grinding operation by the grinding device of the present embodiment.

  As shown in FIG. 4A, when the plate-shaped work W is placed on the holding table 21, the suction force of the holding surface 23 holds the plate-shaped work W so that the center of the plate-shaped work W is aligned with the center of the holding surface 23. Further, the non-contact measuring means 50 is positioned above the plate-shaped work W, the measurement light is projected from the light projecting portion 51 toward the plate-shaped work W, and the measurement process is started. Then, the holding table 21 is rotated by the rotating means 22, the grinding wheel 45 is brought close to the plate-shaped work W on the holding table 21, and the resin layer 75 is ground. The thinning of the resin layer 75 allows the measurement light to pass through the resin layer 75, and the measurement light is reflected by the upper surface 76 of the resin layer 75, the upper end surface 73 of the columnar electrode 72, and the upper surface 77 of the semiconductor wafer 70.

  In the non-contact measuring means 50, the first to third reflected lights R1, R2, and R3 reflected by the upper surface 76 of the resin layer 75, the upper end surface 73 of the columnar electrode 72, and the upper surface 77 of the semiconductor wafer 70 (FIG. 3B). (See) is received. The thickness t2 of the resin on the upper end of the columnar electrode 72 and the thickness t1 of the resin on the semiconductor wafer 70 are measured from the optical path length differences of the first to third reflected lights R1, R2, R3. When the resin thickness t2 on the upper end of the columnar electrode 72 and the resin thickness t1 on the semiconductor wafer 70 are measured, the resin on the semiconductor wafer 70 when the resin thickness t2 on the upper end of the electrode 72 becomes zero. Target thickness t3 is set.

  Therefore, in the subsequent grinding operation, since it is sufficient to grind while measuring the resin thickness t1 on the semiconductor wafer 70, it is not necessary to measure the resin thickness t2 on the upper end of the electrode 72. As described above, the control unit 60 does not control the thickness t2 of the resin on the upper end of the electrode 72 to zero, but controls the thickness t1 of the resin on the semiconductor wafer 70 to approach the target thickness t3. It

  As shown in FIG. 4B, while the thickness t1 of the resin on the semiconductor wafer 70 is measured in real time by the non-contact measuring means 50, the grinding feeding means 30 (see FIG. 4A) feeds the grinding means 40 by grinding. Then, the resin layer 75 is ground until the resin thickness t1 of the semiconductor wafer 70 reaches the target thickness t3, and the upper end surface 73 of the columnar electrode 72 is exposed from the upper surface 76 of the resin layer 75. Therefore, even if the thickness t2 of the resin on the upper end of the electrode 72 becomes small, the measurement accuracy of the non-contact measuring means 50 does not deteriorate, and only the resin is removed from the upper end of the electrode 72. Since the electrode 72 is not ground, the processing dust such as metal powder does not adhere to the grinding wheel 46.

  As described above, in the grinding apparatus 1 of the present embodiment, the first reflected light R1 reflected by the upper surface 76 of the resin layer 75, the second reflected light R2 reflected by the upper end surface 73 of the electrode 72, and the semiconductor wafer 70. Of the plurality of thickness data measured from the third reflected light R3 reflected by the upper surface 77 of the above, the smaller thickness data is determined as the resin thickness t2 on the upper end of the electrode 72. Thereby, the thickness t1 of the resin on the semiconductor wafer 70 and the thickness t2 of the resin on the upper end of the electrode 72 can be discriminated from the plurality of thickness data. At this time, since the target thickness t3 of the resin on the semiconductor wafer 70 when the thickness t2 of the resin on the upper end of the electrode 72 is zero is known, thereafter, without measuring the thickness t2 of the resin on the upper end of the electrode 72, It suffices to grind while measuring only the resin thickness t1 of the semiconductor wafer 70. By grinding the resin thickness t1 on the semiconductor wafer 70 so as to approach the target thickness t3, only the resin on the upper end of the electrode 72 can be ground to expose the upper end surface 73 of the electrode 72.

  The present invention is not limited to the above-mentioned embodiment, and can be implemented with various modifications. In the above-described embodiment, the size and shape shown in the accompanying drawings are not limited to this, and can be appropriately changed within the range where the effect of the present invention is exhibited. Other than the above, the present invention can be appropriately modified and implemented without departing from the scope of the object of the present invention.

  For example, in the above-described embodiment, the grinding feed means 30 is configured to feed the grinding means 40 in the grinding feed direction in which the grinding means 40 approaches and separates from the holding means 20, but the present invention is not limited to this configuration. The grinding feed means 30 may be configured to relatively feed the holding means 20 and the grinding means 40 in the grinding feed direction. For example, the grinding means 40 feeds the holding means 20 in the grinding feed direction. May be configured as follows.

  Further, in the above-described embodiment, the non-contact measuring means 50 is configured as a spectroscopic interferometer, but the configuration is not limited to this. The non-contact measuring means 50 may measure the resin thickness of the plate-shaped workpiece W in a non-contact manner, and may measure the resin thickness of the plate-shaped workpiece W using another optical measuring device. .

  As described above, the present invention has an effect that only the resin layer can be ground to expose the upper end surface of the electrode, and in particular, a grinding device using a spectral interferometer for measuring the thickness of the resin layer is provided. It is useful.

1 Grinding Device 20 Holding Means 21 Holding Table 22 Rotating Means 30 Grinding Feeding Means 40 Grinding Means 45 Grinding Wheels 46 Grinding Wheels 50 Non-contact Measuring Means 51 Light Emitting Parts 55 Light Receiving Parts 56 Calculating Means 57 Judging Means 60 Control Means 70 Semiconductor Wafers 72 Electrode 73 Upper end surface of electrode 75 Resin layer 76 Upper surface of resin layer 77 Upper surface of semiconductor wafer R1 First reflected light R2 Second reflected light R3 Third reflected light W Plate work

Claims (1)

A grinding device for grinding a columnar electrode standing on the upper surface of a semiconductor wafer with a resin to grind the upper surface of the resin layer of a plate-like work forming a resin layer with a grinding wheel,
Holding means having a rotating means for rotating a holding table for holding the plate-like work, grinding means for rotatably mounting a grinding wheel for grinding the resin layer of the plate-like work held by the holding means, and the grinding A grinding feed means for feeding the means and the holding means in a grinding feed direction relatively approaching and separating from each other, and a non-contact measuring means for non-contactly measuring the thickness of the resin ground by the grinding wheel. ,
The non-contact measuring means,
A light projecting section for projecting measurement light from above the plate-like work held by the rotating holding means;
A light receiving portion for receiving the reflected light of the measurement light reflected by the plate-like work,
The first reflected light reflected by the upper surface of the resin, the second reflected light reflected by the upper end surface of the electrode, and the upper surface of the semiconductor wafer, which are received by the light receiving portion while the resin layer is being ground by the grinding wheel. From the difference in optical path length from the third reflected light, when the resin thickness t1 on the semiconductor wafer, the resin thickness t2 on the upper end of the electrode, and the resin thickness t2 on the upper end of the electrode are zero. Calculation means for calculating a plurality of thickness data including a target thickness t3 of the resin on the semiconductor wafer,
A determination unit that determines the smaller thickness data of the resin thickness t1 on the semiconductor wafer and the resin thickness t2 on the upper end of the electrode calculated by the calculation unit as the resin thickness t2 on the upper end of the electrode. Prepare,
When the thickness t1 of the resin on the semiconductor wafer is measured by the non-contact measuring means, the resin is ground by the grinding wheel, and when the thickness t2 of the resin on the upper end of the electrode becomes zero by the calculating means. Then, the target thickness t3 of the resin on the semiconductor wafer is calculated, and after the calculation , the thickness t1 of the resin on the semiconductor wafer is set to the target thickness t3 without calculating the thickness t2 of the resin on the upper end of the electrode. A grinding device that grinds the resin by the grinding means until it becomes.

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