JP2018183828A - Method for dressing grinding wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding wheel-dressing method capable of flatly forming the bottom face of a grinding wheel.SOLUTION: A grinding wheel-dressing method comprises: a holding step ST1 of holding a dressing board on the holding surface of a chuck table; a first dressing step ST2 of feeding for grinding, a grinding wheel at a first speed which becomes a grinding condition exceeding the capacity discharging a grinding waste by the grinding wheel and grinding the dressing board to compulsorily dress the grinding wheel; and a second dressing step ST3 of feeding for grinding, the grinding wheel at a second speed slower than the first speed capable of corresponding to the capacity discharging the grinding waste by the grinding wheel and grinding the dressing board to consume the grinding wheel. In the first dressing step ST2, the grinding face of the grinding wheel is ground down by the grinding waste and accordingly, a concave portion is formed by the grinding waste. In the second dressing step ST3, the convex portions on both sides of the concave portion is removed and consequently, the grinding wheel is flattened.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a dressing method for a grinding wheel.

  In order to reduce the thickness of various plate-like workpieces such as semiconductor wafers, optical device wafers, resin package substrates, etc., a grinding apparatus that grinds the workpieces with a grinding wheel in which grinding wheels are arranged annularly is known. (For example, refer to Patent Document 1). In the grinding wheel, new abrasive grains are exposed one after another due to wear by the self-generated blade action, and maintain a sharpness of a certain level or more. Therefore, the grinding wheel needs to be properly consumed, but it is not suitable depending on the processing conditions.

  As a grinding wheel, for example, a long life grindstone has been developed for grinding a large amount of workpieces with a single grinding wheel while suppressing the amount of wear. The long life grindstone is a grinding grindstone formed of vitrified bond, which is a relatively hard type bond material. When dressing a long-life grindstone, if the long-life grindstone grinds the dressing board under standard dressing conditions, the bottom surface of the long-life grindstone is not uniformly consumed as a whole, and a recess is likely to occur on the bottom surface. The concave portion is generated because the grinding scrap between the bottom surface of the long life grindstone and the dressing board is difficult to be discharged, and the center of the bottom surface is scraped by the grinding scrap.

JP 2006-015423 A

  As described above, when the workpiece is ground with the grinding wheel in which the concave portion is generated, the shape of the concave portion is transferred to the workpiece. In particular, in the case of grinding a resin package substrate that does not require finish grinding, the transfer of the recesses becomes significant.

  This invention is made | formed in view of such a point, The place made into the objective provides the dressing method of the grinding stone which can form the bottom face of a grinding stone flat.

  In order to solve the above-described problems and achieve the object, the grinding wheel dressing method of the present invention includes a chuck table for holding a workpiece, and a grinding machine in which abrasive grains are attached to a lower end of a spindle and bonded by vitrified bonds. Using a grinding apparatus comprising a grinding unit that grinds a workpiece held on the chuck table with a grindstone, and a grinding feed unit that grinds and feeds the grinding unit in a direction perpendicular to the holding surface, the grinding grindstone is A dressing method for a grinding wheel to be dressed, comprising: a holding step for holding a dressing board on a holding surface of the chuck table; and the grinding wheel at a first speed that provides a grinding condition that exceeds a discharging ability of the grinding wheel. A first dressing step in which the grinding wheel is forcibly ground to forcibly sharpen the grinding wheel A second dressing step of grinding and feeding the dressing board by grinding and feeding the grinding wheel at a second speed slower than the first speed, which can be supported by the grinding scrap discharging ability of the grinding wheel, and depleting the grinding wheel In the first dressing step, the bottom surface of the grinding wheel is scraped by the grinding scraps to form recesses in the bottom surface, and in the second dressing step, the convex portions on both sides of the recess in the grinding wheel Is removed and flattened.

  Further, in the dressing method of the grinding wheel, in the first dressing step and the second dressing step, the dressing board is ground while rotating the chuck table, and the rotation speed of the chuck table in the second dressing step is The rotation speed of the first dressing step may be slower.

  The dressing method for a grinding wheel of the present invention has an effect that the bottom surface of the grinding wheel can be formed flat.

FIG. 1 is a perspective view illustrating a configuration example of a grinding apparatus that performs a dressing method for a grinding wheel according to a first embodiment. FIG. 2 is a perspective view of a grinding wheel of the grinding apparatus shown in FIG. FIG. 3 is a cross-sectional view of a part of the grinding wheel of the grinding wheel shown in FIG. FIG. 4 is a perspective view showing an example of a workpiece to be processed by the grinding apparatus shown in FIG. FIG. 5 is a flowchart showing a dressing method for a grinding wheel according to the first embodiment. FIG. 6 is a perspective view showing a dressing board and the like held on the chuck table in the holding step of the dressing method of the grinding wheel shown in FIG. FIG. 7 is a side view showing a first dressing step and a second dressing step of the grinding wheel dressing method shown in FIG. FIG. 8 is an enlarged cross-sectional view showing the main parts of the grinding wheel and the like during the first dressing step of the grinding stone dressing method shown in FIG. FIG. 9 is an enlarged cross-sectional view showing a main part of the grinding wheel or the like during the second dressing step of the grinding wheel dressing method shown in FIG. FIG. 10 is an enlarged cross-sectional view of the grinding wheel and the like after the second dressing step of the grinding wheel dressing method shown in FIG.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

Embodiment 1
A grinding stone dressing method according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating a configuration example of a grinding apparatus that performs a dressing method for a grinding wheel according to a first embodiment. FIG. 2 is a perspective view of a grinding wheel of the grinding apparatus shown in FIG. FIG. 3 is a cross-sectional view of a part of the grinding wheel of the grinding wheel shown in FIG. FIG. 4 is a perspective view showing an example of a workpiece to be processed by the grinding apparatus shown in FIG.

  The dressing method of the grinding wheel according to the first embodiment is performed by the grinding apparatus 1 shown in FIG. The grinding apparatus 1 grinds and thins the surface 202 of the workpiece 201 shown in FIG. 4, and forms the surface 202 flatly. In the first embodiment, a workpiece 201 to be processed by the grinding apparatus 1 includes a resin substrate 203, a plurality of devices (not shown) mounted on the resin substrate 203, and a mold in which the devices are sealed, as shown in FIG. A resin package substrate including a resin 204. The device of the workpiece 201 is mounted on each region of the resin substrate 203 defined by the division lines 205 shown by dotted lines in FIG. 4 formed in a lattice shape.

  The workpiece 201 is divided along the scheduled division line 205 after the surface 202 of the mold resin 204 is ground and formed flat by the grinding device 1. In the first embodiment, the workpiece 201 is the resin package substrate shown in FIG. 4 in which the surface 202 does not need to be subjected to finish grinding. However, in the present invention, a circle whose base material is silicon, sapphire, gallium or the like is used. A plate-shaped semiconductor wafer or an optical device wafer may be used, or a so-called TAIKO wafer in which a central portion is thinned and a thick portion is formed on an outer peripheral portion, a ceramic plate, a glass plate, or the like may be used.

  As shown in FIG. 1, the grinding apparatus 1 includes an apparatus base 2, a chuck table 10, a grinding unit 20, a processing feed unit (not shown), a grinding feed unit 40, and a control unit 90. The grinding apparatus 1 according to the first embodiment is a so-called uniaxial grinding apparatus that includes only one grinding unit 20 and forms the surface 202 of the resin package substrate, which is the workpiece 201, flat.

  The chuck table 10 holds the workpiece 201 by placing the workpiece 201 attached to the disk-shaped protection member 210 on the holding surface 11 via the protection member 210. The chuck table 10 has a disk shape in which a portion constituting the holding surface 11 is formed of porous ceramic or the like, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown) and placed on the holding surface 11. The workpiece 201 is held by suction. The chuck table 10 is supported by a support base 12 that is rotatable about an axis parallel to the Z-axis direction. The Z-axis direction is parallel to the vertical direction and orthogonal to the holding surface 11.

  The machining feed unit is installed on the apparatus base 2 and relatively moves the chuck table 10 in the Y-axis direction, which is a machining feed direction parallel to the holding surface 11. The processing feed unit moves the support base 12 supporting the chuck table 10 in the Y-axis direction, thereby bringing the chuck table 10 away from the grinding unit 20 and the processing position 102 below the grinding unit 20. Is moved over.

  The grinding feed unit 40 is fixed to the column 3 erected on the apparatus base 2, and feeds the grinding unit 20 in the Z-axis direction, which is a cutting feed direction orthogonal to the holding surface 11. The column 3 is formed in a column shape standing from the end of the apparatus base 2 near the processing position 102. The grinding feed unit 40 lowers the grinding unit 20 to bring the grinding wheel 23 of the grinding unit 20 close to the workpiece 201 held on the chuck table 10 at the processing position 102, and raises the grinding unit 20 to move the grinding wheel 23. The workpiece is held away from the workpiece 201 held on the chuck table 10 at the machining position 102.

  The processing feed unit and grinding feed unit 40 includes a well-known ball screw 41 provided rotatably around the axis, a well-known pulse motor 42 that rotates the ball screw 41 around the axis, and the chuck table 10 or the grinding unit 20. A well-known guide rail 43 is provided that is movably supported in the Y-axis direction or the Z-axis direction.

  In the grinding unit 20, the grinding wheel 23 is pressed against the workpiece 201 held on the chuck table 10 by the grinding feed unit 40, and the grinding table 27 of the grinding wheel 23 is used to feed the grinding table 27 while supplying a grinding liquid such as pure water. 10 to grind the workpiece 201 held on the workpiece. As shown in FIG. 1, the grinding unit 20 includes a spindle housing 21 provided so as to be movable in the Z-axis direction by a grinding feed unit 40, and a spindle 22 provided in the spindle housing 21 so as to be rotatable about an axis. A grinding wheel 23 attached to the lower end of the spindle 22. The spindle 22 is arranged in parallel with the Z-axis direction, and is rotated around the axis by a spindle motor 24. The spindle 22 has a disk-shaped wheel mount 25 attached to the lower end thereof to which a grinding wheel 23 is attached.

  As shown in FIG. 2, the grinding wheel 23 includes a wheel base 26 attached to the wheel mount 25, and a plurality of grinding wheels 27 disposed on the wheel base 26 in a substantially annular shape. The wheel base 26 is made of stainless steel or aluminum alloy and is formed in an annular shape.

  The plurality of grinding wheels 27 are disposed on a base surface 28 facing the chuck table 10 disposed at a processing position 102 of a wheel base 26 attached to the wheel mount 25. The plurality of grinding wheels 27 are disposed on the base surface 28 and attached to the lower end of the spindle 22. The plurality of grinding wheels 27 are arranged on the base surface 28 of the wheel base 26 at equal intervals in the circumferential direction. In the first embodiment, as shown in FIG. 3, each grinding wheel 27 is bonded with abrasive grains 272 such as diamond or CBN (Cubic Boron Nitride) by vitrified bonds 271 that are bonding materials. In the first embodiment, the grinding wheel 23 is a so-called long life wheel in which the amount of wear of the grinding wheel 27 is 3/4 or less when grinding is performed under the same conditions as a grinding wheel having a conventional grinding wheel. The consumption amount is, for example, the dimension in the Z-axis direction of the grinding wheel 27 that decreases per unit time.

  Before the grinding wheel 23 is shipped from the factory and grinds the workpiece 201, the grinding surface 29 that is the bottom surface facing the workpiece 201 of the grinding wheel 27 is not flat, and the grinding surface 29 is the holding surface. 11 is often at least one of a state that is not parallel to 11 and a state in which the grinding surfaces 29 of the plurality of grinding wheels 27 are not located on the same plane. When grinding the workpiece 201, the grinding wheel 23 is such that the grinding surfaces 29 of the plurality of grinding wheels 27 are located on the same plane, and the grinding surfaces 29 are flat and parallel to the holding surface 11. desirable.

  The control unit 90 controls the above-described components of the grinding apparatus 1 to cause the grinding apparatus 1 to perform the machining operation on the workpiece 201 and the dressing method of the grinding wheel according to the first embodiment. The control unit 90 is a computer. The control unit 90 includes an arithmetic processing device having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a read only memory (ROM) or a random access memory (RAM), and an input / output interface device. And have. The arithmetic processing device of the control unit 90 performs arithmetic processing according to a computer program stored in the storage device, and sends a control signal for controlling the grinding device 1 to the above-mentioned of the grinding device 1 via the input / output interface device. Output to the specified component. In addition, the control unit 90 is connected to a display unit (not shown) configured by a liquid crystal display device that displays a processing operation state, an image, and the like, and an input device used when an operator registers processing content information and the like. . The input device includes at least one of a touch panel provided in the display unit, a keyboard, and the like.

  A dressing method for a grinding wheel according to the first embodiment will be described. FIG. 5 is a flowchart showing a dressing method for a grinding wheel according to the first embodiment. FIG. 6 is a perspective view showing a dressing board and the like held on the chuck table in the holding step of the dressing method of the grinding wheel shown in FIG. FIG. 7 is a side view showing a first dressing step and a second dressing step of the grinding wheel dressing method shown in FIG. FIG. 8 is an enlarged cross-sectional view showing the main parts of the grinding wheel and the like during the first dressing step of the grinding stone dressing method shown in FIG. FIG. 9 is an enlarged cross-sectional view showing a main part of the grinding wheel or the like during the second dressing step of the grinding wheel dressing method shown in FIG. FIG. 10 is an enlarged cross-sectional view of the grinding wheel and the like after the second dressing step of the grinding wheel dressing method shown in FIG.

  The dressing method for a grinding wheel (hereinafter simply referred to as a dressing method) according to Embodiment 1 is a method for dressing the grinding wheel 27 using the grinding device 1. The dressing means that the grinding wheel 27 is conspicuous before or while the workpiece 201 is ground after being shipped from the factory, and the grinding surfaces 29 of the plurality of grinding wheels 27 are positioned on the same plane, The grinding surface 29 is flat and parallel to the Y-axis direction. In the first embodiment, the dressing method dresses the grinding wheel 27 of the grinding wheel 23 before being shipped from the factory and grinding the workpiece 201.

  As shown in FIG. 5, the dressing method includes a holding step ST1, a first dressing step ST2, and a second dressing step ST3.

  The holding step ST <b> 1 is a step of holding the dressing board 100 shown in FIG. 6 on the holding surface 11 of the chuck table 10. The dressing board 100 is for dressing the grinding wheel 27. In the first embodiment, the dressing board 100 dresses the grinding wheel 27 before being shipped from the factory and grinding the workpiece 201. The dressing board 100 is formed in a disk shape having a rectangular cross section. The dressing board 100 is configured by mixing abrasive grains such as WA (white alundum, alumina) and GC (green carbonite, silicon carbide) into a bond material of resin or ceramics.

  In the holding step ST1, the operator of the grinding apparatus 1 attaches the dressing board 100 to the disc-like holding member 110 and holds the holding member on the holding surface 11 of the chuck table 10 at the loading / unloading position 101 as shown in FIG. The dressing board 100 is placed via 110. In the holding step ST1, the control unit 90 sucks and holds the dressing board 100 on the holding surface 11 via the holding member 110 when receiving an instruction to start dressing from the operator via the input device. The dressing method proceeds to the first dressing step ST2.

  The first dressing step ST2 is a step in which the grinding wheel 27 is ground and fed at the first speed 301 shown in FIG. 7, and the dressing board 100 is ground to forcibly sharpen the grinding wheel 27. In the first dressing step ST2, the control unit 90 moves the chuck table 10 from the loading / unloading position 101 to the machining position 102 by the machining feed unit. In the first dressing step ST2, as shown in FIG. 7, the control unit 90 rotates the grinding wheel 23 of the chuck table 10 and the grinding unit 20 around the axis center at the machining position 102, and the grinding wheel of the grinding unit 20 is rotated. The grinding wheel 27 of 23 is ground and fed at the first speed 301 toward the dressing board 100 to dress the grinding surface 29 of the grinding wheel 27. As described above, in the first dressing step ST2, the control unit 90 grinds the dressing board 100 while rotating the chuck table 10 around the axis.

  During the dressing of the first dressing step ST2, the grinding wheel 27 and the like are ground, and grinding waste 400 formed by grinding is generated between the grinding surface 29 and the surface of the dressing board 100 as shown in FIG. To do. Since the grinding wheel 27 is moved toward the dressing board 100, the grinding waste 400 moves in the direction of being pushed toward both sides of the grinding surface 29 along the radial direction of the grinding wheel 23. However, the first speed 301 of the first dressing step ST2 is such that the grinding wheel 27 is faster than the dressing board 100 before the majority (eg, more than half) of the grinding waste 400 is pushed out between the grinding surface 29 and the dressing board 100. It is the speed to move toward. For this reason, the first speed 301 is a speed at which most (for example, half or more) of the grinding waste 400 stays between the grinding surface 29 and the dressing board 100. Thus, the first speed 301 is a grinding condition that exceeds the discharge capacity of the grinding waste 400 of the grinding wheel 27.

  For this reason, in the first dressing step ST2, the grinding dust 400 grinds the grinding surface 29, and the grinding wheel 23 before the dressing shown by the dotted line in FIG. 8 is applied to the grinding wheel 23 as shown by the solid line in FIG. A recess 30 is formed in which the center in the radial direction is recessed from both sides in the radial direction. Thus, in the first dressing step ST <b> 2, the grinding surface 29 of the grinding wheel 27 is scraped by the grinding dust 400 to form the recesses 30 in the grinding surface 29, and the protrusions 31 are formed on both sides in the radial direction of the recesses 30. . The dressing method proceeds to the second dressing step ST3 after performing the first dressing step ST2 for a predetermined time.

  The second dressing step ST3 is a step in which the grinding wheel 27 is ground and fed at a second speed 302 slower than the first speed 301, the dressing board 100 is ground, and the grinding wheel 27 is consumed. In the second dressing step ST3, the control unit 90 makes the rotation speed of the chuck table 10 slower than the first dressing step ST2, and rotates the chuck wheel 10 and the grinding wheel 23 of the grinding unit 20 around the axis, The grinding wheel 27 of the grinding wheel 23 of the grinding unit 20 is ground and fed at a second speed 302 toward the dressing board 100 to dress the grinding surface 29 of the grinding wheel 27. As described above, in the second dressing step ST3, the control unit 90 grinds the dressing board 100 while rotating the chuck table 10 about the axis. The rotation speed of the chuck table 10 in the second dressing step ST3 is slower than the rotation speed of the chuck table 10 in the first dressing step ST2.

  As shown in FIG. 9, the second speed 302 of the second dressing step ST <b> 3 is a grinding wheel after most (for example, half or more) of the grinding waste 400 is pushed out between the grinding surface 29 and the dressing board 100. Reference numeral 27 denotes a moving speed toward the dressing board 100. For this reason, the second speed 302 is a speed at which most (for example, half or more) of the grinding waste 400 is discharged from between the grinding surface 29 and the dressing board 100. As described above, the second speed 302 is a grinding condition that can be dealt with by the discharging ability of the grinding waste 400 of the grinding wheel 27. For this reason, in the second dressing step ST3, it is possible to suppress the grinding waste 400 from grinding the grinding surface 29, and the grinding surface 29 is a recess 30 of the grinding wheel 27 before the second dressing step ST3 indicated by a dotted line in FIG. The convex portions 31 on both sides are removed, and after the second dressing step ST3, as shown by a solid line in FIG. In the dressing method, when the control unit 90 performs the second dressing step ST3 for a predetermined time, the rotation of the chuck table 10 and the grinding wheel 23 is stopped, and the grinding unit 20 is moved away from the chuck table 10. In the dressing method, the control unit 90 moves the chuck table 10 to the loading / unloading position 101, stops the suction holding of the dressing board 100, and ends the dressing method.

  As described above, the dressing method according to the first embodiment performs the second dressing step ST3 in which the grinding wheel 27 is ground and fed at the second speed 302 that can be handled by the discharging ability of the grinding dust 400 of the grinding wheel 27. Grinding waste 400 generated by dressing can be discharged from between the grinding surface 29 and the dressing board 100. For this reason, the dressing method according to the first embodiment can suppress the grinding scraps 400 from grinding the grinding surface 29 in the second dressing step ST3. As a result, in the dressing method according to the first embodiment, the convex portions 31 on both sides of the grinding wheel 27 can be preferentially consumed, and the grinding surface 29 of the grinding wheel 27 can be formed flat. In addition, since the dressing method according to the first embodiment can form the grinding surface 29 of the grinding wheel 27 flat, the shape of the grinding surface 29 of the grinding wheel 27 is transferred to the surface 202 of the workpiece 201 after grinding. Even if it is done, there exists an effect that the surface 202 does not become unevenness.

  In the dressing method according to the first embodiment, the rotation speed of the chuck table 10 in the second dressing step ST3 is slower than the rotation speed of the chuck table 10 in the first dressing step ST2. 400 can be discharged from between the grinding surface 29 and the dressing board 100.

  Moreover, since the dressing method according to the first embodiment performs the first dressing step ST2 for grinding and feeding at the first speed 301 higher than the second speed 302 before the second dressing step ST3, the dressing method is applied. It can suppress that required time becomes long.

  The present invention is not limited to the first embodiment. That is, various modifications can be made without departing from the scope of the present invention. In the first embodiment, the grinding apparatus 1 having only one grinding unit 20 performs the dressing method. However, the dressing method of the present invention finishes the rough grinding unit for rough grinding the workpiece 201 and the workpiece 201. You may implement by the grinding apparatus provided with the finish grinding unit to grind at least.

DESCRIPTION OF SYMBOLS 1 Grinding device 10 Chuck table 11 Holding surface 20 Grinding unit 22 Spindle 27 Grinding wheel 29 Grinding surface (bottom surface)
30 Concave part 31 Convex part 40 Grinding feed unit 100 Dressing board 201 Work piece 271 Vitrified bond 272 Abrasive grain 301 First speed 302 Second speed Z Direction perpendicular to holding surface ST1 Holding step ST2 First dressing step ST3 Second Dressing step

Claims (2)

A chuck table for holding a workpiece, a grinding unit for grinding the workpiece held on the chuck table with a grinding wheel attached to the lower end of the spindle and bonded with vitrified bonds, and holding the grinding unit A grinding wheel dressing method for dressing the grinding wheel using a grinding apparatus comprising a grinding feed unit for grinding and feeding in a direction orthogonal to the surface,
A holding step for holding the dressing board on the holding surface of the chuck table;
A first dressing step in which the grinding wheel is ground and fed at a first speed that is a grinding condition exceeding a grinding waste discharging capacity of the grinding wheel, the dressing board is ground to forcibly sharpen the grinding wheel;
A second dressing step for grinding and feeding the dressing board by grinding and feeding the grinding wheel at a second speed slower than the first speed that can be handled by the grinding waste discharging ability of the grinding wheel; With
In the first dressing step, the bottom surface of the grinding wheel is scraped by the grinding scraps to form concave portions on the bottom surface, and in the second dressing step, the convex portions on both sides of the concave portion of the grinding wheel are removed and flattened. A method for dressing a grinding wheel, characterized in that: In the first dressing step and the second dressing step, the dressing board is ground while rotating the chuck table,
The grinding wheel dressing method according to claim 1, wherein the rotation speed of the chuck table in the second dressing step is slower than the rotation speed of the first dressing step.

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