JP2020015118A - Creep feed grinding method - Google Patents

Abstract

To measure a thickness of a work-piece during creep feed grinding so as to make differences of thicknesses thereof in grinding small.SOLUTION: A mount 73 comprises a hole 730 penetrating through upper and lower surfaces, at a side closer to outside than a rotary shaft 70 and closer to inside than a grindstone 741 and means 38 that radiates measurement light passing through the penetration hole 730, passes reflected light from an upper surface of a work-piece through the penetration hole 730 and receives the light, so as to measure a height of the upper surface of the work-piece. The creep feed grinding method comprises: a step in which a table 30 is positioned closer to a front side than a front side of a grinding wheel 74 in a Y-axis direction and further a lower surface of the grindstone 741 is positioned lower than the upper surface of the work-piece; a step of memorizing an initial height position of the grinding means 7; a step in which the table 30 is moved from a front side to a rear side with respect to the grinding means 7 and an initial value Z1 at which a surface to be ground of the work-piece is measured by the measuring means 38 is memorized; and a step in which the table 30 is moved with respect to the grinding means 7, the initial value Z1 is subtracted from a value at which the surface to be ground of the work-piece is measured by the measuring means 38, and the grinding means 7 is made to approach to a table holding surface by a difference of thicknesses which is caused by ablation of the grindstone 741 whenever the difference is calculated.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a creep feed grinding method for grinding a plate-like work.

  When a plate-shaped work provided with electrodes is suction-held by a holding table, and the upper surface of the plate-shaped work is rotated by a grinding wheel in which a grinding wheel is arranged in an annular shape to perform creep feed grinding, the grinding wheel is positioned at a predetermined height. When the outer peripheral surface (outer surface) of the grinding wheel is ground while moving the holding table holding the plate-like work in the Y-axis direction parallel to the holding surface direction of the holding table toward the grinding wheel, a large grinding force is secured. (For example, see Patent Documents 1 and 2).

JP 2010-016181 A JP 2009-69759 A

  When creep-feed grinding a plate-like work on the outer peripheral surface of the grinding wheel as described above, the thickness difference of the plate-like work, which is caused by the consumption of the grinding wheel, unless the entire surface to be ground of the plate-like work is ground. Can not be measured.

  Therefore, when performing creep feed grinding on a plate-shaped work on the outer peripheral surface of the grinding wheel, there is a problem in that the thickness of the plate-shaped work is measured during grinding to reduce the thickness difference of the plate-shaped work after grinding. .

  In order to solve the above problems, the present invention provides a holding table having a holding surface for holding a plate-like work, and a tip of a rotating shaft connected to the center of the upper surface of the mount, and a grinding wheel is annularly arranged on the lower surface of the mount. A grinding means for mounting a ring-shaped grinding wheel, rotating the rotating shaft to grind a plate-like work with the grinding wheel, and moving the holding table and the grinding means relatively in the Y-axis direction parallel to the holding surface direction. Creep feed for grinding a plate-like workpiece using a grinding device having a Y-axis direction moving means for moving and a Z-axis direction moving means for moving the grinding means in a Z-axis direction perpendicular to the holding surface. In the grinding method, the rotating shaft is inclined from the Z-axis direction with respect to the holding surface, and the direction in which the distance between the lower surface of the grinding wheel and the holding surface is minimized is defined as the front of the grinding wheel. Between the lower surface of the grinding wheel and the holding surface The side where the separation is greatest is defined as the rear of the grinding wheel, and the mount includes a through-hole penetrating the upper and lower surfaces outside the rotation axis and inside the grinding wheel of the mounted grinding wheel. The apparatus irradiates the upper surface of the plate-shaped work with the measurement light passing through the through hole, receives the reflected light reflected on the upper surface through the through hole, receives the light, and measures the upper surface height of the plate-shaped work in a non-contact manner. An upper surface height measuring unit, and using the Y-axis direction moving unit, the holding table is positioned forward of the grinding wheel mounted on the grinding unit in the Y-axis direction, and further, in the Z-axis direction. A positioning step of positioning the lower surface of the grinding wheel below the upper surface of the plate-like work held by the holding table by using a moving unit; and a grinding step of storing an initial height position of the grinding unit positioned in the positioning step. Means After the height storing step and the positioning step, the holding table is moved in the direction from the front to the rear with respect to the grinding means using the Y-axis direction moving means, and the lower surface of the grinding wheel is An initial upper surface height storing step of storing an initial value of the surface to be ground of the plate-like workpiece ground with the outer peripheral surface by the upper surface height measuring means, and using the Y axis direction moving means, The initial value stored in the initial upper surface height storage step from the value measured by the upper surface height measuring device on the surface to be ground of the plate-like workpiece ground by moving the holding table with respect to the grinding device. Calculating a difference caused by the consumption of the grinding wheel, and controlling the Z-axis direction moving means each time the difference is calculated, and bringing the grinding means closer to the holding surface by the distance of the difference. And a creep feed grinding method comprising:

  In the creep feed grinding method according to the present invention, the upper surface height measuring means irradiates the upper surface of the plate-shaped work with the measurement light passing through the through hole of the mount and receives the reflected light reflected on the upper surface through the through hole to receive the light. The height of the upper surface of the plate-like work is measured in a non-contact manner, and the holding table is positioned in front of the grinding wheel mounted on the grinding means in the Y-axis direction using the Y-axis direction moving means. Using the direction moving means, a positioning step of positioning the lower surface of the grinding wheel below the upper surface of the plate-like work held by the holding table, and an initial height of the grinding means for storing the initial height position of the grinding means positioned in the positioning step After the storing step and the positioning step, the holding table is moved in the direction from the front to the rear with respect to the grinding means using the Y-axis direction moving means, and the lower surface and the outer peripheral surface of the grinding wheel An initial upper surface height storing step of storing an initial value measured first by the upper surface height measuring means for the surface to be ground of the plate-like workpiece ground by the above, and holding to the grinding means using the Y axis direction moving means. The difference caused by the consumption of the grinding wheel by subtracting the initial value stored in the initial upper surface height storing step from the value measured by the upper surface height measuring means on the surface to be ground of the plate-like workpiece ground by moving the table. And a correction step of controlling the Z-axis direction moving means each time the difference is calculated, and bringing the grinding means closer to the holding surface by the distance of the difference. Can be reduced in thickness.

It is a perspective view showing an example of a grinding device. A side view illustrating a state in which a holding table is positioned forward of a grinding wheel mounted on a grinding means in a Y-axis direction, and a lower surface of a grinding wheel is positioned below an upper surface of a plate-like work held by the holding table. It is. Using the Y-axis direction moving means, the holding table is moved in the direction from the front to the rear of the grinding wheel with respect to the grinding means, and the plate-like work is started to be ground by the lower surface and the outer peripheral surface of the grinding wheel. It is a side view explaining. It is a side view explaining the case where the grinding means is brought close to the holding surface of the holding table by the controlled Z-axis direction moving means, and the correction to reduce the thickness difference of the plate-like work after the grinding is performed. It is a side view explaining the state where the whole upper surface of the plate-like work was finished by the lower surface and the outer peripheral surface of the front grinding wheel. FIG. 7 is a side view illustrating a state in which a lower surface of a front grinding wheel is positioned lower than an upper surface of a plate-shaped work and a plate-shaped work is positioned forward of the front grinding wheel in a conventional creep feed grinding method. In the conventional creep feed grinding method, the holding table was moved in the direction from the front to the back of the grinding wheel with respect to the grinding means, and the plate-like work was started to be ground by the lower surface and the outer peripheral surface of the front grinding wheel. It is a side view explaining a state. FIG. 7 is a side view illustrating a state in which the entire upper surface of a plate-like work has been ground by the lower surface and the outer peripheral surface of the front grinding wheel in the conventional creep feed grinding method.

The grinding device 1 shown in FIG. 1 is a device for grinding a plate-like work W held on a holding table 30 by a rotating grinding wheel 74, and includes a device base 10 extending in the Y-axis direction and a rear side on the device base 10. (In the + Y direction).
The front (−Y direction side) of the grinding device 1 on the device base 10 is an attachment / detachment area where the plate-shaped work W is attached to / detached from the holding table 30, and the rear of the device base 10 is the grinding unit 7. This is a grinding area in which the plate-shaped work W held on the holding table 30 is ground.

The plate-shaped work W shown in detail in FIG. 2 includes, for example, a rectangular substrate W1 made of PCB or the like and a rectangular chip W2 whose base material is silicon or the like. The lower surface of the chip W2 is joined to the upper surface of the substrate W1.
A device (not shown) is formed on the upper surface of the chip W2. A plurality of columnar electrodes E are provided upright on the surface of the device. The electrode E is made of, for example, copper as a main element.
The upper surface of the chip W2 is sealed with a resin layer J such as an epoxy resin, and the upper end of each electrode E is covered with the resin layer J.

The upper surface of the resin layer J becomes the upper surface Wa of the plate-shaped work W, and the lower surface of the substrate W1 becomes the lower surface Wb of the plate-shaped work W. The lower surface Wb of the plate-shaped work W may be protected by, for example, attaching a protection tape (not shown).
An example of the size of the rectangular plate-shaped work W is 600 mm long × 300 mm wide.
The configuration of the plate-shaped work W is not limited to this example.

For example, the holding table 30 illustrated in FIG. 1 includes a suction unit 300 made of a porous member or the like and sucking the plate-shaped work W, and a frame 301 that supports the suction unit 300. The suction unit 300 communicates with a suction source (not shown) such as a vacuum generator, and the suction force generated by suction by the suction source is transmitted to the holding surface 300a that is an exposed surface of the suction unit 300. The holding table 30 can suck and hold the plate-shaped work W on the holding surface 300a.
Further, the holding table 30 is rotatable around the axis in the Z-axis direction by rotating means 34 disposed below the holding table 30 while being surrounded by the cover 39.

Below the holding table 30, the cover 39, and the bellows cover 39a connected to the cover 39, a Y-axis direction moving means 14 for moving the holding table 30 in the Y-axis direction parallel to the holding surface 300a is provided. I have. The Y-axis direction moving means 14 includes a ball screw 140 having an axis in the Y-axis direction, a pair of guide rails 141 disposed in parallel with the ball screw 140, a motor 142 connected to the ball screw 140 and rotating the ball screw 140. And a movable plate 143 having a nut screwed into the ball screw 140 and a bottom portion sliding on the guide rail 141. When the motor 142 rotates the ball screw 140, the movable plate 143 The holding table 30 disposed on the movable plate 143 via the rotating means 34 moves in the Y-axis direction by being guided by the rail 141 and moving in the Y-axis direction. The bellows cover 39a expands and contracts in the Y-axis direction as the holding table 30 moves.
Note that the rotating means 34 does not need to be provided because it is stopped during the grinding process.

  On the front surface of the column 11, a Z-axis direction moving means 5 for moving the grinding means 7 in the Z-axis direction perpendicular to the Y-axis direction and perpendicular to the holding surface 300a of the holding table 30 is provided. The Z-axis direction moving means 5 includes a ball screw 50 having an axis in the Z-axis direction, a pair of guide rails 51 disposed in parallel with the ball screw 50, and a motor connected to the upper end of the ball screw 50 to rotate the ball screw 50. 52, and an elevating plate 53 in which an inner nut is screwed into the ball screw 50 and a side portion slides on the guide rail 51. When the motor 52 rotates the ball screw 50, the elevating plate 53 Reciprocating in the Z-axis direction guided by the rail 51, the grinding means 7 fixed to the elevating plate 53 is ground and fed in the Z-axis direction.

  The grinding means 7 includes a rotating shaft 70 whose axial direction is inclined from the Z-axis direction with respect to the holding surface 300a of the holding table 30, a housing 71 that rotatably supports the rotating shaft 70, and rotationally drives the rotating shaft 70. Motor 72, a circular plate-shaped mount 73 connected to the tip of a rotating shaft 70, a grinding wheel 74 mounted on the lower surface of the mount 73, and an elevating plate 53 of the Z-axis direction moving means 5 that supports the housing 71. And a holder 75 whose side surface is fixed.

Since the rotating shaft 70 is inclined from the Z-axis direction, the annular grinding wheel 741 is also inclined from the Z-axis direction. The direction in which the distance between the lower surface 741b of the grinding wheel 741 shown in FIG. 2 and the holding surface 300a of the holding table 30 is minimized (the −Y direction side) is defined as the front of the grinding wheel 74 (that is, the front of the grinding wheel 741). I do. The side where the distance between the lower surface 741b of the grinding wheel 741 and the holding surface 300a is the maximum (the + Y direction side in FIG. 2) is defined as the rear side of the grinding wheel 74 (the rear side of the grinding wheel 741).
In FIG. 2, some of the components of the grinding device 1 are simplified and omitted.

The inclination angle of the rotating shaft 70 from the Z-axis direction is a slight angle, and a predetermined value is set as the angle according to the diameter of the grinding wheel 74, for example.
For example, when the diameter (mm) of the grinding wheel 74 is Φ300, the inclination angle of the rotating shaft 70 from the Z-axis direction is the height position of the lower surface 741b in front of the grinding wheel 741 and the rear of the grinding wheel 741. The angle L0 between the height position of the lower surface 741b and the height position is set to, for example, 20 μm to 30 μm.
When the diameter (mm) of the grinding wheel 74 is Φ500, for example, the inclination angle of the rotating shaft 70 from the Z-axis direction is determined by the height position of the lower surface 741b in front of the grinding wheel 741 and the height position of the grinding wheel 741. The difference L0 from the height position of the rear lower surface 741b is set to an angle of, for example, 30 μm to 50 μm.
The holding surface 300a of the holding table 30 is ground with the lower surface 741b of the grinding wheel 741 in a state where the rotating shaft 70 is inclined, and the lower surface 741b and the holding surface 300a are made parallel to each other. The workpiece W is held and ground by the lower surface 741b of the grinding wheel 741.

  As shown in FIGS. 1 and 2, the mount 73 includes a through hole 730 that penetrates the upper and lower surfaces of the mount 73 outside the rotation shaft 70 and inside the grinding wheel 741 of the mounted grinding wheel 74. A plurality of (for example, nine) through holes 730 are formed at equal intervals in the circumferential direction, and are positioned below the grinding means 7 through the through holes 730 when the mount 73 is viewed from the + Z direction. The plate-shaped work W on the holding table 30 can be visually recognized.

  The grinding wheel 74 includes an annular wheel base 740, and a plurality of substantially rectangular parallelepiped grinding wheels 741 are annularly arranged in a region on the outer peripheral side of the bottom surface of the wheel base 740. The grinding wheel 741 is formed by fixing diamond abrasive grains or the like with a predetermined bonding agent. The grinding wheel 741 is, for example, a grinding wheel for grinding a plate-like work W provided with an electrode E made of copper or the like. The ratio and size of the holes in the grinding wheel are smaller than those of a normal grinding wheel. It is big. The reason why the ratio and size of the holes in the grinding wheel 741 are set to be large is that when the electrode E is ground with a normal grinding wheel, the copper constituting the electrode E tends to clog the holes of the grinding wheel. This is to prevent clogging. On the other hand, since the grinding wheel 741 is a grinding wheel in which the ratio and size of the holes are set to be large, the amount of wear accompanying the grinding of the plate-shaped work W is larger than that of a normal grinding wheel.

  As shown in FIG. 1, a grinding water nozzle 36 is provided at a position adjacent to the grinding wheel 74 of the grinding means 7 in a state where the grinding water nozzle 36 is lowered to a position at which the plate-shaped work W is ground. Is connected to a grinding water supply source 360.

The grinding device 1 irradiates the upper surface Wa of the plate-shaped work W held on the holding table 30 with measurement light that has passed through the through-hole 730 formed in the mount 73, receives reflected light reflected on the upper surface Wa, and receives the reflected light. An upper surface height measuring means 38 for measuring the height of the upper surface Wa of the workpiece W in a non-contact manner is provided.
The upper surface height measuring means 38 is, for example, a regression reflection type optical displacement sensor, a light projecting unit for irradiating the upper surface Wa of the plate-shaped work W with measuring light, and a collimator for converting the measuring light into parallel light. It comprises a lens, a light receiving unit such as a CCD for detecting the reflected light reflected on the upper surface Wa of the plate-shaped work W, and the like.

  In the present embodiment, as shown in FIG. 1, the upper surface height measuring means 38 is supported by, for example, a support member 37 attached to the front surface of the holder 75, and the rotation orbit of the plurality of through holes 730 of the mount 73. Is located above. The support member 37 may not be provided, and the mounting position of the upper surface height measuring means 38 is not limited to the example shown in FIG.

  As shown in FIG. 1, the grinding apparatus 1 includes a control unit 9 that includes a CPU and a storage unit 91 such as a memory and controls the entire apparatus. The control unit 9 is electrically connected to the Z-axis direction moving unit 5, the Y-axis direction moving unit 14, and the like by wiring (not shown), and is controlled by the Z-axis direction moving unit 5 under the control of the control unit 9. The moving operation and positioning height of the means 7 in the Z-axis direction, the moving speed of the holding table 30 by the Y-axis direction moving means 14, and the like are controlled.

For example, the above-described motor 52 of the Z-axis direction moving means 5 is a pulse motor that operates by a driving pulse supplied from a pulse oscillator (not shown). The control means 9 counts the number of driving pulses supplied to the Z-axis direction moving means 5 and recognizes the height position of the grinding means 7.
The motor 52 of the Z-axis direction moving means 5 may be a servomotor, and a rotary encoder may be connected to the servomotor. The rotary encoder is connected to a control unit 9 also having a function as a servo amplifier. After an operation signal is supplied from the control unit 9 to the servomotor, the rotary encoder transmits an encoder signal (the number of rotations of the servomotor) to the control unit 9. Output to The control means 9 calculates the amount of movement of the grinding means 7 in the Z-axis direction based on the received encoder signal and recognizes the height position.

  Hereinafter, each step in the case where the plate-shaped work W is creep feed-ground by the grinding apparatus 1 will be described with reference to FIGS. 1 to 4.

(1) Positioning Step First, the plate-shaped work W shown in FIGS. 1 and 2 is placed on the holding surface 300 a of the holding table 30 with the resin layer J facing upward in the attachment / detachment area on the device base 10. Then, the suction force generated by the operation of the suction source (not shown) connected to the holding table 30 is transmitted to the holding surface 300a, so that the plate work W is sucked and held by the holding table 30.

  The Y-axis direction moving means 14 shown in FIG. 2 moves the holding table 30 holding the plate-shaped workpiece W by suction from the attachment / detachment area on the apparatus base 10 to a predetermined position in the + Y direction in the grinding area. Reference numeral 30 is positioned at the start position of the feed in the Y-axis direction. That is, as shown in FIG. 2, the distance between the lower surface 741 b of the grinding wheel 741 and the holding surface 300 a of the holding table 30 is smaller than the front (−Y direction side) of the grinding wheel. The plate-shaped work W held on the holding table 30 is positioned.

Further, the grinding means 7 is sent in the −Z direction by the Z-axis direction moving means 5, and under the control of the Z-axis direction moving means 5 by the control means 9, the front of the grinding wheel 741 which is the lowermost end of the grinding wheel 741. The grinding means 7 is positioned at a predetermined height position where the lower surface 741b of the plate-shaped workpiece W cuts into the upper surface Wa of the plate-shaped work W. That is, the lower surface 741b of the front grinding wheel 741 is positioned below the upper surface Wa of the plate-shaped work W held on the holding table 30.
Before the grinding, a setup for storing the height position of the grinding means 7 in which the lower surface 741b of the front (−Y direction side) grinding wheel 741 is in contact with the holding surface 300a of the holding table 30 is performed. The position of the lower surface 741b of the front grinding wheel 741 positioned lower than the upper surface Wa of the plate-shaped work W held on the holding table 30 is determined by the height position of the grinding means 7 stored in the setup and the finished thickness of the plate-shaped work W. The upper position. That is, the distance between the lower surface 741b of the front grinding wheel 741 and the holding surface 300a of the holding table 30 is a preset finishing thickness of the plate-like work W.

(2) Grinding Means Initial Height Storage Step The height position of the grinding means 7 in the positioning step is a height at which the lower surface 741b and the outer peripheral surface 741d of the front grinding wheel 741 cut a predetermined amount into the resin layer J and the electrode E. And a height position Z0 (initial height position Z0) for setting the ground work W to a desired thickness (finished thickness).
The initial height position Z0 of the grinding means 7 is stored in the storage section 91 of the control means 9.

(3) Initial Top Height Storage Step The motor 72 of the grinding means 7 shown in FIG. 1 drives the rotating shaft 70 to rotate, for example, counterclockwise as viewed from the + Z direction, and the grinding wheel 74 rotates accordingly. . Then, as shown in FIG. 3, the Y-axis direction moving means 14 moves the holding table 30 holding the plate-shaped work W by suction in the + Y direction. Is moved in a direction from the front (−Y direction side) to the rear side (+ Y direction side). Then, the circular upper surface of the resin layer J and the electrode E of the plate-like work W is ground by the lower surface 741b on the front side and the outer peripheral surface 741d of the rotating grinding wheel 741. An example of the ratio of the area of the resin layer J appearing on the upper surface Wa of the plate-shaped work W to be ground to the total area of the circular upper surfaces of all the electrodes E is, for example, resin layer J: circular upper surface of all the electrodes E = 20:80.
Note that the rear side (+ Y direction side) of the rotating grinding wheel 741 does not grind the plate-shaped work W.

  During the grinding, the grinding water sprayed from the grinding water nozzle 36 shown in FIG. 1 is supplied from the outer peripheral surface 741d side of the grinding wheel 741 to the contact portion between the grinding wheel 741 and the plate-shaped work W. Therefore, the grinding can be performed on the inner peripheral surface side of the grinding wheel 741 shown in FIG.

Immediately after the grinding of the upper surface Wa of the plate-shaped work W is started, the height of the upper surface Wa, which is the surface to be ground of the plate-shaped work W, starts to be measured by the upper surface height measuring means 38.
The light projecting part of the upper surface height measuring means 38 shown in FIG. 3 irradiates the ground surface upper surface Wa of the plate-shaped work W with measurement light in the −Z direction. The measurement light is converted into parallel light parallel to the Z-axis direction by the collimator lens, and reaches the plate-shaped workpiece W through any one of the through holes 730 formed in the rotating mount 73. The reflected light from the ground upper surface Wa of the plate-shaped work W passes through the through-hole 730 again, and the light path difference when the light receiving unit receives the light is used to determine the upper surface height measuring means 38 and the plate-shaped work W by the principle of triangulation. The distance to the upper surface Wa is calculated, and the height of the upper surface Wa of the ground plate-like workpiece W is measured. As described above, in the grinding device 1, the upper surface height measuring means 38 can measure the height of the upper surface Wa immediately after the plate-shaped work W is ground, unlike the conventional case, when performing creep feed grinding.
Since the grinding is performed by the grinding water nozzle 36 so as not to generate much spray of the grinding water on the inner peripheral surface side of the grinding wheel 741, the measurement of the upper surface height measuring means 38 is not hindered by the spray. It has become.

Then, the upper surface height measuring means 38 sequentially controls the information on the measured height of the upper surface Wa immediately after the start of the grinding of the measured plate-like work W and the height of the upper surface Wa which has been ground thereafter for each unit time. Send to 9. The information sent to the control unit 9 is sequentially stored in the storage unit 91 of the control unit 9.
An initial value obtained by first measuring the ground upper surface Wa of the plate-shaped work W immediately after the start of the grinding by the upper surface height measuring means 38 is, for example, a height Z1 shown in FIG.

(4) Correction Step As shown in FIG. 4, as the holding table 30 moves in the + Y direction, the upper surface Wa of the plate-shaped work W is ground by the grinding unit 7 and the control unit 9 is provided. The calculating unit 92 shown in FIG. 1 stores the initial upper surface height in the initial upper surface height storing process based on the height (measured value) of the upper surface Wa of the plate-like work W sent from the upper surface height measuring unit 38 to the control unit 9 per unit time. The difference caused by the consumption of the grinding wheel 741 is calculated by subtracting the height Z1 which is the stored initial value. That is, the difference L1 caused by the consumption of the grinding wheel 741 obtained by subtracting the height Z1, which is the initial value, from the height Z2 of the newly measured upper surface Wa of the plate-shaped work W shown in FIG. 4 is calculated.

  The calculated difference L1 is a thickness difference of the plate-shaped work W, and is a consumption amount of the grinding wheel 741 from the beginning of grinding. When the calculation unit 92 calculates the difference L1, the Z-axis direction moving unit 5 moves the grinding unit 7 in the Z-axis direction under the control of the control unit 9 to reduce the thickness difference of the ground plate-like work W. The first correction is performed. In other words, the grinding means 7 located at the initial height position Z0 is brought closer to the plate-like work W sucked and held on the holding surface 300a of the holding table 30 by a distance of the difference L1 (downward) to perform the grinding. Then, the height of the upper surface Wa of the plate-like work W ground after the main correction becomes the height Z1 again, and the ground plate-like work W has a desired thickness.

  Further, the grinding is performed, and the height as the initial value stored in the storage unit 91 from the height position Z3 of the upper surface Wa of the plate-shaped work W newly measured by the upper surface height measuring means 38 shown in FIG. The difference L2 caused by the consumption of the grinding wheel 741 from which the difference Z1 has been subtracted is calculated by the calculation unit 92. The calculated difference L2 is a thickness difference of the plate-shaped work W, and is a consumed amount of the front grinding wheel 741 after the first correction is performed. Then, under the control of the control means 9, a second correction is performed in which the Z-axis direction moving means 5 moves the grinding means 7 in the Z-axis direction to reduce the thickness difference of the plate-like workpiece W after the grinding. That is, the grinding is performed by bringing the grinding means 7 closer to the plate-shaped work W by the distance of the difference L2, so that the height of the upper surface Wa of the plate-shaped work W ground after the second correction is increased to the height Z1 again. , And the ground work W has a desired thickness.

  As described above, the upper surface Wa, which is the surface to be ground of the plate-like workpiece W ground by moving the holding table 30 with respect to the grinding means 7 using the Y-axis direction moving means 14, is used to measure the upper surface height measuring means 38. Subtracts the initial value Z1 stored in the initial upper surface height storing step from the measured value to calculate a difference caused by the consumption of the grinding wheel 741, and every time the difference is calculated, the control means 9 sets the Z-axis direction. The moving means 5 is controlled, and the Z-axis direction moving means 5 performs the correction to bring the grinding means 7 closer to the holding surface 300a of the holding table 30 by the distance of the difference every third unit time and fourth time. Then, the holding table 30 moves to a predetermined position in the −Y direction, and after the entire upper surface Wa of the plate-shaped work W is ground by the lower surface 741 b and the outer peripheral surface 741 d of the front grinding wheel 741, the grinding unit 7 moves to + Z. And is separated from the plate-like work W.

Here, the problems in the conventional creep feed grinding method will be briefly described with reference to FIGS.
In the conventional creep feed grinding method, the grinding means 7 shown in FIG. 6 is sent in the −Z direction by the Z-axis direction moving means 5, and the lower surface 741 b of the front (−Y direction side) grinding wheel 741 is held by the holding table 30. Is positioned at a height position where a predetermined amount is cut into the resin layer J and the electrode E of the plate-shaped work W held at the position. Then, the Y-axis direction moving means 14 moves the holding table 30 holding the plate-shaped work W by suction at a predetermined feed speed in the + Y direction, which is a direction from the front to the rear of the grinding wheel 74. Then, as shown in FIG. 7, the circular upper surface of the resin layer J and the electrode E of the plate-like work W is ground by the lower surface 741b and the outer peripheral surface 741d in front of the rotating grinding wheel 741.

  As shown in FIG. 7, the holding table 30 is moved to a predetermined position in the −Y direction, and after grinding the entire upper surface Wa of the plate-shaped work W with the lower surface 741 b and the outer peripheral surface 741 d in front of the grinding wheel 741, grinding is performed. The means 7 is pulled up in the + Z direction and is separated from the plate-like work W.

  As shown in FIG. 8, for example, when conventional creep feed grinding is performed on a long plate-shaped workpiece W, the thickness at which the grinding wheel 741 starts to enter the plate-shaped workpiece W due to the consumption of the grinding wheel 741. The thickness at which the grinding wheel 741 is separated from the plate-shaped workpiece W is greatly different from the thickness at the point where the grinding wheel 741 is separated from the plate-shaped workpiece W. Further, when the work includes the electrode E made of copper, such as the plate-like work W, the grinding wheel 741 is a grindstone in which the ratio and size of the holes are set to be large. The amount of wear accompanying the grinding of the plate-like work W also increases, and the difference in the thickness becomes particularly large.

  On the other hand, in the creep feed grinding method according to the present invention, the upper surface height measuring means 38 irradiates the upper surface Wa of the plate-shaped work W with the measurement light passing through the through hole 730 of the mount 73 and reflects the reflected light on the upper surface Wa. The light passes through the through-hole 730 and receives light to measure the height of the upper surface of the plate-shaped work W in a non-contact manner. The Y-axis direction moving means 14 is used to move the grinding wheel 74 mounted on the grinding means 7 in the Y-axis direction. The holding table 30 is positioned on the front side (−Y direction side) from the front side (−Y direction side), and the holding table 30 holds the lower surface 741 b in front of the grinding wheel 741 using the Z-axis direction moving means 5. A positioning step of positioning below the upper surface Wa of the plate-like work W; a grinding unit initial height storage step of storing the initial height position Z0 of the grinding unit 7 positioned in the positioning step; After that, the holding table 30 is moved in the direction from the front (−Y direction) to the rear (+ Y direction) with respect to the grinding means 7 using the Y-axis direction movement means 14, and the lower surface 741 b of the grinding wheel 741 is moved. An initial upper surface height storing step of storing an initial value Z1 of the upper surface Wa, which is a surface to be ground of the plate-shaped work W ground with the outer peripheral surface 741d, first measured by the upper surface height measuring means 38; The upper surface Wa, which is the ground surface of the plate-like workpiece W ground by moving the holding table 30 with respect to the grinding means 7 using the means 14, is used to calculate the initial upper surface height from the value measured by the upper surface height measuring means. The difference generated by the consumption of the grinding wheel 741 is calculated by subtracting the initial value Z1 stored in the storing step, and every time the difference is calculated, the control means 9 controls the Z-axis direction moving means 5 to calculate the difference. Distance in the Z-axis direction For and a correction step to approach the holding surface 300a of the grinding means 7 by means 5, it is possible to reduce the thickness difference of the plate-shaped workpiece W after grinding.

  It goes without saying that the creep feed grinding method according to the present invention is not limited to the above-described embodiment, and may be carried out in various forms within the scope of the technical idea. Also, the components of the grinding device 1 illustrated in the accompanying drawings are not limited thereto, and can be appropriately changed within a range in which the effects of the present invention can be exhibited.

W: Plate work W1: Substrate W2: Chip E: Electrode J: Resin layer 1: Grinding device 10: Device base 11: Column 14: Y-axis direction moving means 140: Ball screw 141: One pair of guide rails 142: Motor 143: Movable plate 30: Holding table 300: Suction unit 300a: Holding surface 301: Frame 34: Rotating means 39: Cover 39a: Bellows cover 38: Upper surface height measuring means 37: Support member 5: Z-axis direction moving means 50: Ball screw 51: a pair of guide rails 52: motor 53: lifting plate 7: grinding means 70: rotating shaft 71: housing 72: motor 73: mount 730: through hole 74: grinding wheel 740: wheel base 741: grinding wheel 741b: grinding Lower surface of the grindstone 75: holder 9: control means 91: storage unit 92: calculation unit

Claims (1)

A holding table having a holding surface for holding a plate-like work, and a ring-shaped grinding wheel in which the tip of a rotating shaft is connected to the center of the upper surface of the mount and a grinding wheel is annularly arranged on the lower surface of the mount, and the rotating shaft is mounted. Grinding means for rotating and grinding a plate-like work with the grinding wheel, Y-axis direction moving means for relatively moving the holding table and the grinding means in the Y-axis direction parallel to the holding surface direction, A creep-feed grinding method for grinding a plate-like work using a grinding device having a Z-axis direction moving means for moving the means in a Z-axis direction perpendicular to the holding surface,
The rotation axis is inclined from the Z-axis direction with respect to the holding surface, and the direction in which the distance between the lower surface of the grinding wheel and the holding surface is minimized is defined as the front of the grinding wheel, and the lower surface of the grinding wheel And the direction in which the distance between the holding surface and the holding surface is maximum is defined as the rear of the grinding wheel,
The mount includes a through hole that penetrates the upper and lower surfaces outside the rotation shaft and inside the grinding wheel of the mounted grinding wheel,
The grinding device irradiates the measurement light passing through the through-hole to the upper surface of the plate-shaped work, receives the reflected light reflected on the upper surface through the through-hole, receives the light, and adjusts the height of the upper surface of the plate-shaped work in a non-contact manner. Equipped with an upper surface height measuring means for measuring,
Using the Y-axis direction moving means, the holding table is positioned in front of the grinding wheel mounted on the grinding means in the Y-axis direction from the front, and further, the grinding is performed using the Z-axis direction moving means. A positioning step of positioning the lower surface of the grindstone below the upper surface of the plate-shaped work held by the holding table,
Grinding means initial height storage step of storing the initial height position of the grinding means positioned in the positioning step,
After the positioning step, the holding table is moved in the direction from the front to the rear with respect to the grinding means using the Y-axis direction moving means, and the grinding table is ground on the lower surface and the outer peripheral surface of the grinding wheel. An initial upper surface height storing step of storing an initial value of the ground surface of the plate-shaped work that has been first measured by the upper surface height measuring means,
Using the Y-axis direction moving means, the surface to be ground of the plate-like workpiece ground by moving the holding table with respect to the grinding means is determined from the value measured by the upper surface height measuring means to obtain the initial upper surface. The difference caused by the consumption of the grinding wheel is calculated by subtracting the initial value stored in the height storage step, and every time the difference is calculated, the Z-axis direction moving means is controlled, and only the distance of the difference is calculated. A correction step of bringing the grinding means closer to the holding surface.

Images