Determining method of dresser board, dressing method and processing device

Abstract

To provide a new technique that can prevent a dresser board from being wrongly attached, in utilizing a proper dresser board out of a plurality of kinds of dresser boards.SOLUTION: A determining method of a dresser board comprises a measuring step of measuring irregularities on a surface of a dresser board set on a holding unit and a determining step of determining that there is an error when a numerical value of the measured irregularities on the surface is over a threshold. In the measuring step, the irregularities are measured by any of measurement of the surface by a non-contact type detecting unit, measurement of the depth of the surface by a contact-type detecting unit and analysis of an image photographed by a detecting unit comprising a camera.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for dressing a grinding wheel using a dresser board. [Background technology]

[0002] In the semiconductor device manufacturing process, when composite materials containing silicon, resin, and metal are ground using grinding tools such as grinding wheels, the condition of the grinding wheels can deteriorate due to wear of the diamond abrasive grains contained in the grinding wheels.

[0003] To address this issue, a dresser board made of abrasive grains shaped with a binder is held on a chuck table, and the dresser board is ground with a grinding member to restore the condition of the grinding wheel, a process known as dressing.

[0004] Dressing also has two roles: truing to align the height of the grinding wheel, and exposing the abrasive grains from the grinding wheel's bond material, so it is necessary to use a dresser board that is appropriate for the type of grinding wheel.

[0005] Furthermore, if the wrong dresser board is used from among the multiple dresser boards available, problems such as damage to the grinding wheel or uneven shapes of the segments of each grinding stone arranged circumferentially on the grinding wheel can occur, affecting processing accuracy. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-183359 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, Patent Document 1 discloses a technique for preventing the wrong grinding wheel from being attached by identifying the grinding stone using a sensor.

[0008] However, Patent Document 1 does not include any description of how to identify dresser boards, and the current situation is that this is described in the dresser board manual to warn against attaching the wrong dresser board.

[0009] Therefore, for example, there is a possibility that an operator who is not familiar with the work may attach the dresser board incorrectly, and improvements are needed to prevent this from happening, which could result in damage to the grinding wheel or a decrease in processing quality.

[0010] In view of the above problems, the present invention proposes a novel technique for preventing the wrong dresser board from being attached when using the correct one from among a plurality of types of dresser boards. [Means for solving the problem]

[0011] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0012] According to one aspect of the present invention, a method for evaluating a dresser board includes a measurement step for measuring the unevenness of the surface of a dresser board set in a holding unit, and a judgment step for making an error judgment if the numerical value of the measured unevenness of the surface exceeds a threshold value.

[0013] Furthermore, according to one aspect of the present invention, the measurement of the unevenness in the measurement step is performed by either measuring the surface depth using a non-contact detection unit, measuring the surface depth using a contact detection unit, or analyzing an image captured by a detection unit equipped with a camera.

[0014] According to one aspect of the present invention, a dressing method is provided, comprising: a positioning step of positioning a detection unit above a dresser board set in a holding unit; a measurement step of measuring the unevenness of the surface of the dresser board with the detection unit; a determination step of making an error determination if the numerical value of the measured unevenness of the surface exceeds a threshold value; an abort step of aborting the dressing if an error is determined; and a dressing step of dressing the dresser board with a processing unit if no error is determined.

[0015] According to one aspect of the present invention, a processing device is provided which includes a holding unit for holding a workpiece or a dresser board, a processing unit for processing the workpiece held in the holding unit, a detection unit for measuring the unevenness of the surface of the dresser board held in the holding unit, and a control unit, and the control unit makes an error judgment when the numerical value of the unevenness of the surface measured by the detection unit exceeds a threshold value.

[0016] According to one aspect of the present invention, the detection unit is configured as a non-contact detection unit, a contact detection unit, or a detection unit equipped with a camera. [Effects of the Invention]

[0017] The present invention provides the following effects. That is, according to one aspect of the present invention, even if the wrong dresser board is set, the device can automatically detect the error and prompt the user to set the correct dresser board, thereby solving the problem of incorrect dresser board setting and preventing damage to the grinding wheel and deterioration of processing quality due to the mistake. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram showing an example of a processing apparatus for implementing the present invention; [Figure 2] FIG. 2 is a diagram showing an example of the configuration of a grinding unit. [Figure 3] FIG. 10 is a diagram showing an example of the configuration of a dresser board. [Figure 4] 5A and 5B are diagrams showing measurement of unevenness on the surface of a dresser board by a detection unit. [Figure 5] (A) is a diagram showing the measurement of the surface irregularities of a coarse-grained dresser board. (B) is a diagram showing the measurement of the surface irregularities of a fine-grained dresser board. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The processing device 1 shown in Figure 1 is configured to include a holding unit 30 that holds a workpiece W, and a grinding unit 7 that is a processing unit that processes the workpiece W held by the holding unit 30.

[0020] 1 is configured as a so-called single-axis grinding device equipped with one grinding unit 7, but the present invention can also be applied to a so-called double-axis grinding device equipped with two grinding units for performing rough grinding and finish grinding, respectively.The present invention can also be applied to a configuration in which multiple single-axis grinding devices are arranged side by side to perform rough grinding and finish grinding.

[0021] Furthermore, in the following examples, a grinding device has been used as an example of a processing device, but the present invention can also be applied to a cutting device that has a processing unit equipped with a rotating cutting blade for processing cutting grooves, or a polishing device that has a processing unit for polishing the surface of a workpiece.

[0022] 1, the base 10 of the processing device 1 has its longitudinal direction in the Y-axis direction, and the front (-Y direction side) of the base 10 is configured as a loading / unloading area A2 where the workpiece W is loaded and unloaded into the holding unit 30, and the rear (+Y direction side) of the base 10 is configured as a grinding area A1 where the grinding unit 7 grinds the workpiece W held on the holding unit 30. The grinding area A1 is formed in a processing chamber formed by a cover (not shown), and the grinding unit 7 is housed in the processing chamber.

[0023] The processing device according to the present invention is not limited to a grinding device with a single-axis grinding unit 7 like the processing device 1, but may be a two-axis grinding device equipped with a rough grinding means and a finish grinding means, and capable of positioning the workpiece W below the rough grinding means or the finish grinding means using a rotating turntable.

[0024] The workpiece W is, for example, a circular semiconductor wafer made of a silicon base material or the like. The workpiece W may be made of gallium arsenide, sapphire, gallium nitride, ceramics, resin, silicon carbide, or the like, in addition to silicon, or may be a rectangular package substrate or the like. The workpiece W may have a device formed thereon, or may be a wafer cut from an ingot without a device formed thereon. It may also be a semiconductor wafer whose outer periphery has been edge-trimmed to a predetermined depth from one side.

[0025] 1, the holding unit 30 for holding the workpiece W includes, for example, a circular holding table 30a that suction-holds the workpiece W, and a frame 30d that supports the holding table 30a. The holding table 30a is made of a porous material or the like and is connected to a suction source (not shown), so that the workpiece W is suction-held on the holding surface, which is the exposed surface of the holding table 30a.

[0026] 1, the holding unit 30 is surrounded by a cover 39, and can be rotated about a rotation axis in the Z-axis direction by a table rotation means (not shown) disposed below the cover 39. The holding unit 30 can also be moved back and forth in the Y-axis direction by a Y-axis movement means (not shown) disposed below the cover 39 and a bellows cover 37 connected to the front and rear of the cover 39 shown in FIG.

[0027] 1, an upright wall 11 is erected in the grinding area A1 on the base 10, and a grinding feed mechanism 5 is disposed in front of the upright wall 11, which grinds and feeds the grinding unit 7 in the Z-axis direction (vertical direction) so as to move the grinding unit 7 away from or toward the holding unit 30. The grinding feed mechanism 5 includes a ball screw 50 having an axis in the vertical direction, a pair of guide rails 51 disposed parallel to the ball screw 50, a motor 52 connected to the upper end of the ball screw 50 and rotating the ball screw 50, and an elevator plate 53 whose internal nut is threaded onto the ball screw 50 and whose side portions are in sliding contact with the guide rails 51. When the motor 52 rotates the ball screw 50, the elevator plate 53 is guided by the guide rails 51 and moves back and forth in the Z-axis direction, and the grinding unit 7 fixed to the elevator plate 53 is ground and fed in the Z-axis direction.

[0028] The grinding unit 7 comprises a spindle 70 whose axial direction is the Z-axis direction, a housing 71 that rotatably supports the spindle 70, a motor 72 that rotates and drives the spindle 70, a mount 73 connected to the lower end of the spindle 70, and a grinding wheel 74 that is removably attached to the underside of the mount 73.

[0029] In the loading / unloading area A2, a height gauge 33 is provided on the side of the movement path in the Y-axis direction of the holding unit 30. This height gauge 33 can measure the thickness of the workpiece W held by the holding unit 30 after processing.

[0030] The processing device 1 is equipped with a control unit 19 for controlling each component of the processing device 1. The control unit 19 controls the grinding feed operation of the grinding unit 7 by the grinding feed mechanism 5, the rotation operation of the grinding wheel 74 in the grinding unit 7, and the positioning operation of the holding unit 30 relative to the grinding wheel 74 by the Y-axis moving means.

[0031] The processing device 1 is provided with a display unit 60 configured as, for example, a touch panel type, and is configured to enable various settings to be input by an operator and to display the operating status of the device.

[0032] 2, a device D is formed on the front surface Wa of the workpiece W, and the front surface Wa is suction-held on the holding surface 30b of the holding table 30a via a protective sheet. The back surface Wb of the workpiece W is exposed upward, and this back surface Wb is ground by the grinding wheel 74, thereby thinning the workpiece W.

[0033] The grinding wheel 74 is composed of a metal annular wheel 74a and a plurality of grinding stones 74b, each of which has a substantially rectangular parallelepiped shape and is arranged at intervals in the circumferential direction on the underside of the annular wheel 74a. Each grinding stone 74b is formed, for example, by fixing diamond abrasive grains or the like with a binder (adhesive), and the underside of each grinding stone 74b forms a grinding surface.

[0034] The annular wheel 74a of the grinding wheel 74 is formed with a nozzle (not shown) for spraying out the machining fluid, and the machining fluid is continuously supplied between the grinding surface of the grinding stone 74b and the workpiece W.

[0035] In the above configuration, dressing is performed at a predetermined timing on the grinding stones 74b of the grinding wheel 74. The main purposes of dressing are truing, which aligns the height of the grinding stones 74b, and dressing, which exposes the abrasive grains from the bond material of the grinding stones 74b.

[0036] The predetermined timing for performing dressing is, for example, during the initial setup when introducing the processing apparatus 1 or after grinding a predetermined number of workpieces. When dressing, as shown in Fig. 1, one of multiple types of dresser boards 4A, 4B that corresponds to the grinding stone 74b of the grinding wheel 74 is selected and used.

[0037] For example, if the grinding stone 74b of the grinding wheel 74 is a coarse grinding stone for rough grinding, the dresser board 4A, which also has a coarse grit, is used. If the grinding stone 74b of the grinding wheel 74 is a fine grinding stone for finish grinding, the dresser board 4B, which also has a fine grit, is used.

[0038] 3 shows an example of a dresser board 4A, which has a configuration in which a disk-shaped support portion 41 made of resin such as polyvinyl chloride and a disk-shaped dressing tool portion 42 with a smaller diameter than the support portion 41 are integrated with an adhesive at the center of the upper surface of the support portion 41. The dressing tool portion 42 is formed by kneading abrasive grains made of silicon carbide (SiC), aluminum oxide (Al2O3), or the like with a bond material made of a vitrified bond, a resin bond, or the like, and then firing the mixture.

[0039] As shown in Fig. 3, during dressing, the operator places the dresser board 4A on the holding surface 30b of the holding table 30a. Next, the holding table 30a suction-holds the support portion 41 of the dresser board 4A and moves it below the grinding unit 7. Next, the holding table 30a is rotated at a predetermined rotation speed, and the grinding wheel 74 is lowered at a predetermined grinding feed rate while rotating at a predetermined speed. This allows the dressing to be performed by the grinding stone 74b using the dressing tool portion 42.

[0040] 1, the processing apparatus 1 includes a detection unit 8 for detecting irregularities on the surface of the dresser board 4A. In this embodiment, the detection unit 8 is provided at the tip of a support arm 82, and is configured to be positioned above a holding table 30a positioned in the loading / unloading area A2. The operations of the detection unit 8 and the support arm 82 are controlled by a control unit 19.

[0041] 4, the detection unit 8 is positioned above the dressing tool portion 42 of the dresser board 4A held on the holding table 30a by the control unit 19, and is configured to be able to detect unevenness on the surface of the dressing tool portion 42 in a non-contact manner. The detection unit 8 may be, for example, a non-contact type that detects unevenness on the surface by irradiating a laser, or may be, for example, a contact type height gauge with a contact needle, or a camera that captures an image of the surface of the dressing tool portion 42, and the control unit 19 may analyze the data acquired by these devices to recognize the unevenness.

[0042] As shown in Figure 4, the control unit 19 positions the detection unit 8 above the dressing tool portion 42 of the dresser board 4A and starts measurement, and detects the unevenness of the surface of the dressing tool portion 42, for example, by rotating the holding table 30a once.

[0043] FIG. 5(A) shows an example of detection, in which the holding table 30a (FIG. 4) is rotated with the measurement point set at the position of radius R of the dressing tool portion 42. As shown in the enlarged cross-sectional view, unevenness is formed on the surface, and the state of these unevenness is detected as the holding table 30a rotates, with the horizontal axis representing time T and the vertical axis representing depth D. Note that the enlarged cross-sectional view of FIG. 5(A) shows a dressing tool portion consisting of coarse abrasive grains 4m and a binder 4n, and the enlarged cross-sectional view of FIG. 5(B) shows a dressing tool portion consisting of fine abrasive grains 4x and a binder 4y.

[0044] FIG. 5(A) shows an example of measuring a coarse-meshed dresser board 4A, where it is detected that the deviation exceeds +d to -d from the reference value C depending on the surface unevenness. On the other hand, FIG. 5(B) shows an example of measuring a fine-meshed dresser board 4B, where it is detected that the deviation does not exceed +d to -d from the reference value C depending on the surface unevenness. The reference value C can be defined, for example, from the median of all measured values.

[0045] 5(A)(B), the control unit 19 (FIG. 4) sets the swing range +d to -d as a threshold value, and when a value (depth D) exceeding this threshold value is detected, it can determine that a coarse-grained dresser board 4A is set. On the other hand, when a value (depth D) exceeding this threshold value is not detected, it can determine that a fine-grained dresser board 4B is set.

[0046] Next, an example of how the dressing is performed will be described. 1, two types of grinding wheels 74, one for rough grinding and the other for finish grinding, are used interchangeably to perform both rough grinding and finish grinding. The grinding wheels 74 may be provided with grinding stones 74b for rough grinding or with grinding stones 74b for finish grinding. The control unit 19 recognizes which of the two types of grinding wheels 74 is attached. Two types of dresser boards 4A, 4B are used to accommodate the selection of the two types of grinding wheels 74.

[0047] The control unit 19 stores in advance the above-mentioned threshold values ​​for distinguishing between the two types of dresser boards 4A and 4B. In this embodiment, two types of grinding wheels and dresser boards are assumed, but the number of types may be three or more, and is not particularly limited. When there are many types, a number of threshold values ​​corresponding to the number of types are set in advance.

[0048] Based on the above, when dressing becomes necessary at a predetermined timing in the configuration of FIG. 1, the operator selects a mode for performing dressing on the display unit 60. The control unit 19 moves the holding table 30a to the loading / unloading area A2. The operator sets the dresser board 4A that he / she recognizes as the one to be used on the holding table 30a, and performs an operation on the display unit 60 to start dressing.

[0049] The control unit 19 initiates the dressing sequence. First, an arrangement step is performed in which the detection unit 8 is arranged above the dresser board 4A, as shown in Fig. 4. Specifically, the control unit 19 operates the holding unit 30 and the support arm 82 so that the dressing tool part 42 of the dresser board 4A is positioned directly below the detection unit 8.

[0050] Next, a measurement step is performed in which the dresser board 4A is rotated while measuring the unevenness of the surface of the dressing tool part 42. Specifically, as shown in Fig. 5(A), the dressing tool part 42 rotates, and the unevenness of the surface is measured at the position of the radius R of the dressing tool part 42.

[0051] Next, if the measured surface unevenness value exceeds a threshold, a determination step is executed to determine whether an error has occurred. Specifically, as shown in Fig. 5(A), the control unit 19 calculates a reference value C and determines whether the value exceeds a pre-stored threshold (amplitude +d to -d).

[0052] Next, an abort step is executed to abort the dressing if an error is determined. Specifically, for example, an error is displayed on the display unit 60, and the holding unit 30 and the support arm 82 are operated so that the detection unit 8 is positioned away from above the dresser board 4A.

[0053] The error message displayed on the display unit 60 may be, for example, "Dresser board error" or "Please set the correct dresser board," to inform the operator that an incorrect dresser board has been set.

[0054] The operator checks whether or not the wrong dresser board has been set, then sets the correct dresser board and performs an operation on the display unit 60 again to start dressing.

[0055] On the other hand, if no error is determined, the control unit 19 moves the holding unit 30 to below the grinding unit 7, which is the processing unit, and executes a dressing step in which the grinding unit 7 is lowered and the dresser board 4A is dressed (ground) with the grinding wheel 74b.

[0056] Although the above embodiment is an embodiment that includes the process up to the dressing, it is also possible to use a method for determining whether the correct dresser board has been set, and to put the device into standby mode once the determination is complete.

[0057] As described above, even if the operator sets the wrong dresser board, the device (control unit 19) automatically detects the error and prompts the operator to set the correct dresser board. This solves the problem of incorrectly setting the dresser board, and prevents damage to the grinding wheel and deterioration of processing quality due to the mistake. [Explanation of symbols]

[0058] 1 Processing equipment 4A Dresser Board 4B Dresser Board 5 Grinding feed mechanism 7 Grinding Unit 8 Detection Unit 10 base 11 Upright wall 19 Control Unit 30 Holding Unit 30a Holding table 30b Holding surface 30d frame 33 Height Gauge 41 Support part 42 Dressing tool section 60 display units 70 Spindle 71 Housing 72 Motor 74 Grinding Wheel 74a Annular Wheel 74b Grinding wheel 82 Support arm A1 Grinding area A2 Loading / unloading area C Standard value D Device R radius T time W Workpiece Wa surface Wb back side

Claims

1. a measuring step of measuring the unevenness of the surface of the dresser board set in the holding unit; and a determining step of determining an error when the measured numerical value of the unevenness of the surface exceeds a threshold value.

2. The measurement of the unevenness in the measurement step includes: Surface depth measurement by non-contact detection unit, Surface depth measurement by contact-type detection unit, analysis of images taken by a detection unit comprising a camera; 2. The method for determining a dresser board according to claim 1, wherein the method is carried out by any one of the following methods.

3. a placement step of placing the detection unit above the dresser board set in the holding unit; a measuring step of measuring unevenness on the surface of the dresser board by the detection unit; a determining step of determining an error when the measured value of the surface unevenness exceeds a threshold value; a stop step of stopping the dressing when an error is determined; If no error is determined, a dressing step is performed in which the processing unit dresses the dresser board. A dressing method comprising the steps of:

4. The measurement of the unevenness in the measurement step includes: Surface depth measurement by non-contact detection unit, Surface depth measurement by contact-type detection unit, analysis of images taken by a detection unit comprising a camera; 4. The dressing method according to claim 3, wherein the dressing is performed by any one of the following methods.

5. a holding unit for holding the workpiece or the dresser board; a processing unit that processes the workpiece held by the holding unit; a detection unit for measuring the unevenness of the surface of the dresser board held by the holding unit; a control unit; The control unit determines an error when the numerical value of the surface unevenness measured by the detection unit exceeds a threshold value.

6. The detection unit comprises: The detection unit may be a non-contact type, a contact type, or a camera type.

6. The processing device according to claim 5.

Images