JP2007301665A - Grinding wheel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To grind a wafer made of a difficult-grinding material such as a SIC, sapphire, and lithium tantalate without generating surface burning and surface tearing-off. <P>SOLUTION: A grinding wheel 20 is formed by mixing the diamond abrasives 22 and fine metal balls 23 into a resin bond 21, so that the metal balls 23 causing comparatively soft contact with counter-materials functions as a buffer material between diamond abrasives 22 and a wafer. The metal balls also have a cooling function due to a superior thermal conductivity, and a cutting edge generation function based on the dropout of the diamond abrasives 22 because the metal balls 23 are apt to drop out from the surface of the grinding wheel due to an excellent spherical ball. Consequently, the wafer formed by the difficult-grinding material such as the SIC can be effectively ground without generating the surface burning and surface tearing-off. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a grinding wheel including at least a grindstone and a wheel base that holds the grindstone in an annular shape, and a method for manufacturing the same.

  A wafer formed by dividing a plurality of devices such as IC, LSI, LED, etc. by dividing lines is divided into individual devices by a dividing device such as a dicing device or a laser processing device, and used for electronic devices such as mobile phones and personal computers. Is done.

  Here, the wafer is formed of SIC, sapphire, lithium tantalate, etc., and the back surface is polished by a grinding apparatus equipped with a grinding wheel before being divided into individual devices by the dividing apparatus, and has a predetermined thickness. To be processed.

JP 2001-205560 A

  However, when the back surface of a wafer formed of difficult-to-cut materials such as SIC, sapphire, lithium tantalate, etc. is ground with a grinding wheel of a grinding device, there is a problem that desired grinding processing cannot be performed due to surface burning, stuffiness, etc. In addition, it is necessary to use a processing apparatus having a relatively low production efficiency, such as a lapping apparatus or a polishing apparatus.

  The present invention has been made in view of the above, and a grinding wheel capable of grinding a wafer formed of a difficult-to-cut material such as SIC, sapphire, lithium tantalate, and the like without causing surface burning or stuffiness, and its manufacture It aims to provide a method.

  In order to solve the above-described problems and achieve the object, a grinding wheel according to the present invention is a grinding wheel including at least a grindstone and a wheel base that holds the grindstone in an annular shape, It contains at least a resin bond, superabrasive grains, and fine metal spheres.

  The grinding wheel according to the present invention is characterized in that, in the above invention, the superabrasive grains are diamond abrasive grains, and the fine metal spheres are nickel spheres.

  The grinding wheel according to the present invention is characterized in that, in the above invention, the diamond abrasive grains have a particle size of 1 to 50 μm, and the nickel spheres have a particle size of 10 to 100 μm.

  Further, the grinding wheel according to the present invention is characterized in that, in the above-mentioned invention, the blending is a weight ratio of resin bonds 6 to 10, diamond abrasive grains 15 to 25, and nickel balls 65 to 79.

  A grinding wheel manufacturing method according to the present invention is a grinding wheel manufacturing method including at least a grindstone and a wheel base that holds the grindstone in an annular shape, and includes a resin bond, superabrasive grains, and fine particles. A molding step of kneading a metal ball at an appropriate ratio to produce a molded product of a predetermined shape, and sintering to produce a sintered product by sintering the molded product at a temperature of 160 ° C. to 180 ° C. for half a day And a segment forming step for forming the sintered product into a segment-type grindstone having a predetermined shape, and a joining step for bonding the segment-type grindstone to the annular wheel base via a bonding agent. It is characterized by.

  The grinding wheel manufacturing method according to the present invention is characterized in that, in the above invention, the superabrasive grains are diamond abrasive grains, and the fine metal spheres are nickel spheres.

  Moreover, the manufacturing method of the grinding wheel which concerns on this invention is set to the said invention, The particle diameter of the said diamond abrasive grain is 1 micrometer-50 micrometers, The particle diameter of the said nickel sphere is 10 micrometers-100 micrometers, It is characterized by the above-mentioned.

  Moreover, the manufacturing method of the grinding wheel which concerns on this invention is the said invention. WHEREIN: A compounding ratio is the resin bond 6-10, the diamond abrasive grains 15-25, and the nickel balls 65-79, It is characterized by the above-mentioned.

  According to the grinding wheel and the method of manufacturing the same according to the present invention, the grinding wheel is formed by mixing diamond abrasive grains and fine metal balls into the resin bond to form a grinding wheel. Functions as a cushioning material between the diamond abrasive grains and the wafer, and also has a cooling function due to excellent thermal conductivity, and a cutting edge function due to diamond abrasive grains falling off due to the fact that metal balls are easy to fall off In combination with the above, there is an effect that a wafer formed of a difficult-to-cut material such as SIC can be efficiently ground without causing surface burning and stuffiness.

  Hereinafter, a grinding wheel mounted on a grinding apparatus which is the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is an external perspective view showing a configuration example of a grinding wheel 10 of the present embodiment. The grinding wheel 10 according to the present embodiment includes at least a plurality of grindstones 20 formed in a segment shape and a wheel base 30 that holds the grindstones 20 in a ring shape with a predetermined gap 11. Here, the wheel base 30 is formed with a plurality of screw holes 31 and a grinding water supply path 32 for fixing to a mount of a grinding apparatus to be described later. Further, as shown in FIG. 2 (d), a ring shape for embedding the grindstone 20 later using a lathe or the like on the free surface 33 on the side where the grindstone 20 is disposed of the wheel base 30 is provided. A grindstone burying portion 34 is formed by the groove.

  On the other hand, the grindstone 20 of the present embodiment is configured to include at least a resin bond, superabrasive grains, and fine metal balls. Here, with reference to FIG. 2, the manufacturing process of the grinding wheel 10 including the manufacturing process of the grindstone 20 of this Embodiment is demonstrated. FIG. 2 is a perspective view showing the manufacturing process of the grinding wheel in the order of steps.

  First, a powder obtained by kneading resin bonds, superabrasive grains, and fine metal spheres in an appropriate ratio is filled in a mold 40 as shown in FIG. It shape | molds with a hot press into the disk shape shown, and the molded product 41 is produced | generated (molding step). In this case, the curing temperature of the resin is about 160 ° C to 170 ° C. Here, resin such as phenol is used as the resin bond, diamond abrasive is used as the superabrasive, and nickel sphere is used as the fine metal sphere. In this case, the particle diameter of the diamond abrasive grains is preferably 1 μm to 50 μm, whereas the particle diameter of the nickel sphere is preferably about 10 μm to 100 μm. Moreover, it is preferable that a mixing | blending is resin (resin bond) 6-10, diamond abrasive grains 15-25, and nickel spheres 65-79 by a weight ratio, for example, resin (resin bond) 8wt in this Embodiment. %, Diamond abrasive grains 20 wt%, and nickel spheres 72 wt%. As such nickel spheres, for example, Ni balls 100 μm, 80 μm, etc. sold by Hitachi Metals Admet may be used.

  Next, the molded product 41 after molding as shown in FIG. 2B is sintered at a temperature of 160 ° C. to 180 ° C. for half a day to produce a sintered product 42 as shown in FIG. (Sintering step). And the produced | generated sintered compact 42 is shape | molded by the dicer 43 using the dicer 43, and shape | molded into the segment type grindstone 20 of a predetermined size and a predetermined shape (molding step).

  Then, the plurality of segment-type grindstones 20 are bonded by adhering an epoxy resin as a bonding agent 44 to the grindstone embedded portion 34 of the wheel base 30 as shown in FIG. (Coupling step) As shown in FIG. 2E, the grinding wheel 10 in which a plurality of segment-type grindstones 20 are annularly held on the wheel base 30 with a predetermined gap 11 is completed.

  The grinding wheel 10 manufactured as described above is mounted on, for example, a grinding apparatus 50 shown in FIG. FIG. 3 is a schematic perspective view showing a configuration example of the grinding device 50. The grinding device 50 holds a wafer 51 formed of a difficult-to-cut material such as SIC and can rotate the chuck table 52, and grinding that rotatably supports the grinding wheel 10 that grinds the wafer 51 held on the chuck table 52. Means 60 and grinding feed means 70 for grinding and feeding the grinding means 60 are provided.

  First, the chuck table 52 is connected to a drive source (not shown) and can rotate. The chuck table 52 is provided so as to be movable in the X-axis direction by a feed mechanism such as a ball screw, a nut, or a pulse motor.

  The grinding means 60 includes a grinding wheel 10, a housing 61, a mount 63 that is rotatably attached to the lower end of the housing 61 and supports the grinding wheel 10 that is attached by a bolt 62, and a spindle that supports and rotates the mount 63. 64, a motor 65 that rotationally drives the spindle 64, and a moving base 66 on which a housing 61 is mounted. The moving base 66 has guided rails 661, and the guided rails 661 are movably fitted to guide rails 55 provided on the support plate 54 of the housing 53 so that the grinding means 60 moves in the vertical direction. Supported as possible.

  The grinding feed means 70 is for grinding and feeding the grinding wheel 10 in the vertical direction by moving the moving base 66 of the grinding means 60 along the guide rail 55. The grinding feed means 70 includes a male screw rod 71 which is disposed on the support plate 54 in the vertical direction parallel to the guide rail 55 and is rotatably supported, a pulse motor 72 for rotationally driving the male screw rod 71, and a moving base. 66 and a female screw block (not shown) that is screwed with the male screw rod 71.

  The chuck table 52 holding the wafer 51 is rotated, and the grinding wheel 60 is lowered by the grinding feed means 70 while the grinding wheel 10 is rotated by the motor 65, whereby the segment type grindstone 20 of the rotating grinding wheel 10 is moved to the wafer. Grinding is performed in contact with the upper surface of 51. At this time, as shown in FIG. 4, the upper surface of the wafer 51 passes around the grindstone 20 being ground from the grinding water supply source through the spindle 64, the passage in the mount 63, and the grinding water supply passage 32 of the grinding wheel 30. Grinding water is supplied, and the grindstone 20 is cooled and grinding waste is discharged.

  Here, the grinding operation by the grindstone 20 of the grinding wheel 10 of the present embodiment will be described. FIG. 5 is a diagram illustrating a state in which the surface state of the grindstone 20 of the present embodiment is photographed with a microscope. According to the grindstone 20 of the present embodiment, as schematically shown in the blow-out portion in FIG. 5, a resin bond 21 made of phenol resin as a component, superabrasive grains 22 made of diamond abrasive grains, and nickel balls As shown by black circles, a large number of drop marks 24 of the metal spheres 23 have been confirmed.

  That is, in the grindstone 20 of the present embodiment, by mixing the fine metal spheres 23, the metal spheres 23 that are relatively soft to hit are formed between the superabrasive grains 22 (diamond abrasive grains) and the wafer 51 to be ground. The superabrasive grains 22 (diamond abrasive grains) induced by the cooling function by the metal spheres 23 being excellent in thermal conductivity and the metal spheres 23 being true spheres and being easily dropped from the surface of the grindstone 20. In combination with the cutting edge function due to omission, the wafer 51 formed of a difficult-to-cut material such as SIC can be efficiently ground without causing surface burning or stuffiness.

  Here, the grinding experiment result of the SIC wafer using the grinding wheel 10 of the present embodiment and the conventional grinding wheel will be described. First, the wafer 51 to be ground was obtained by attaching a SIC wafer having a diameter of 3 inches and a thickness of 380 μm on a glass wafer having a diameter of 4 inches. Moreover, the grindstone of the conventional grinding wheel was formed by kneading superabrasive grains in vitrified bonds. In addition, the grinding conditions are all that the rotation speed of the spindle 64 is 2500 rpm, the rotation speed of the chuck table 51 is 7 rpm, the grinding water amount is 3.0 liter / min, and the grinding feed speed is 0.2 μm / s for the conventional grinding wheel. The grinding wheel 10 of the present embodiment is 0.5 μm / s.

  FIG. 6 is a diagram showing the results of such an experiment. In a grinding apparatus using a conventional grinding wheel, the spindle load power value exceeded the set value (1500 W), the grinding was terminated in the middle, and the sample wafer was damaged due to a high grinding load. Is. On the other hand, in the grinding apparatus using the grinding wheel 10 having the grindstone 20 of the present embodiment, the spindle load power value increases every grinding, but it was confirmed that the grinding is possible.

  In this embodiment, the example of application to the case of a SIC wafer has been described as the wafer 51 to be ground. However, the grinding of the wafer 51 formed of a difficult-to-cut material such as sapphire or lithium tantalate is described. You may make it apply.

It is an external appearance perspective view which shows the structural example of the grinding wheel of this Embodiment. It is a perspective view which shows the manufacturing process of a grinding wheel in order of a process. It is a schematic perspective view which shows the structural example of a grinding apparatus. It is sectional drawing which shows the mode of grinding water supply. It is a figure which shows a mode that the surface state of the grindstone of this Embodiment was image | photographed with the microscope. It is a figure which shows the result of experiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Grinding wheel 20 Grinding wheel 21 Resin bond 22 Super abrasive grain 23 Fine metal sphere 30 Wheel base 41 Molded product 42 Sintered product 44 Bonding agent

Claims (8)

A grinding wheel comprising at least a grindstone and a wheel base for holding the grindstone in an annular shape,
The grinding wheel according to claim 1, wherein the grinding wheel includes at least a resin bond, superabrasive grains, and fine metal balls.   The grinding wheel according to claim 1, wherein the superabrasive grains are diamond abrasive grains, and the fine metal spheres are nickel spheres.   3. The grinding wheel according to claim 2, wherein the diamond abrasive grains have a particle diameter of 1 μm to 50 μm, and the nickel spheres have a particle diameter of 10 μm to 100 μm.   4. The grinding wheel according to claim 2, wherein the blending is resin bonds 6 to 10, diamond abrasive grains 15 to 25, and nickel spheres 65 to 79 in a weight ratio. A grinding wheel comprising at least a grindstone and a wheel base for holding the grindstone in an annular shape,
A molding step in which a resin bond, superabrasive grains, and fine metal spheres are kneaded at an appropriate ratio to produce a molded product having a predetermined shape,
A sintering step of sintering the molded product at a temperature of 160 ° C. to 180 ° C. for half a day to produce a sintered product;
A segment molding step of molding the sintered product into a segment-shaped grindstone having a predetermined shape;
A bonding step of bonding the segment-type grindstone to the annular wheel base via a bonding agent;
A method for producing a grinding wheel, comprising:   6. The grinding wheel manufacturing method according to claim 5, wherein the superabrasive grains are diamond abrasive grains, and the fine metal spheres are nickel spheres.   The method for manufacturing a grinding wheel according to claim 6, wherein the diamond abrasive grains have a particle diameter of 1 μm to 50 μm, and the nickel spheres have a particle diameter of 10 μm to 100 μm.   8. The method for manufacturing a grinding wheel according to claim 6, wherein the blending is resin bonds 6 to 10, diamond abrasive grains 15 to 25, and nickel spheres 65 to 79 in a weight ratio.

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