JP5889663B2 - Method for polishing quartz wafer end face and rotating grindstone - Google Patents

Description

  The present invention relates to a method for polishing a quartz wafer end face and a rotating grindstone used therefor.

  In the conventional polishing process of the crystal wafer end face, first, after coarsely polishing with a small grindstone (for example, about # 400 to # 1200) having a relatively large abrasive grain size, as disclosed in Patent Document 1, As a finishing process, multiple quartz wafers are bonded together with a known wax material and stacked, and the quartz wafers are rotated together while pouring loose abrasive slurry between the end faces of the quartz wafers and the polishing brush. A polishing brush is brought into contact with the end face of the crystal wafer, and the end face of the crystal wafer is mirror-polished with loose abrasive slurry.

JP 2006-231396 A

  However, when mirror polishing with loose abrasive slurry is performed as a finishing process, the finishing process takes a long time and the entire polishing process is long because the polishing method is changed from rough polishing to finishing process during the polishing process. Resulting in inefficiency. In addition, since a plurality of polishing methods are required, it is also a factor in increasing the cost of end face processing.

  Furthermore, since the loose abrasive slurry is used for finishing, the waste liquid treatment also leads to longer end face processing, inefficiency, and higher costs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a novel quartz wafer end face polishing method that is efficient and low-cost, and a rotating grindstone used therefor.

In order to achieve the above object, a first configuration of a rotating grindstone according to the present invention is a rotating grindstone for polishing an end face of a crystal wafer. , A ring-shaped resin bond grindstone part in which abrasive grains are bonded by resin bond, and the metal bond grindstone part and the resin bond grindstone part are coaxially laminated and fixed. The ring width of the resin bond grindstone part is metal It is characterized by being wider than the ring width of the bond grindstone .

  The configuration of the second rotating grindstone of the present invention is the same as that of the first configuration described above. The rotating grindstone of the present invention further includes a first disk plate having a first through hole in the rotation center axis, and a rotation center axis. A second disk plate having a second through hole and coaxially and interchangeably connected to the first disk plate, wherein the metal bond grindstone part and the resin bond grindstone part are respectively the first disk It is joined to either one of the plate and the second disk plate and the other outer peripheral surface.

  The configuration of the third rotating grindstone of the present invention is that in the second configuration, the first disk plate has a protruding portion surrounding the first through hole, and the second through hole of the second disk plate is It can be fitted to the protrusion.

  The configuration of the fourth rotary grindstone of the present invention is any one of the first to third configurations described above, wherein the outer peripheral end surfaces of the metal bond grindstone portion and / or the resin bond grindstone portion are each provided with a groove portion extending in the circumferential direction. It is characterized by having.

  In the fifth rotary grindstone of the present invention, in any one of the first to fourth configurations, the metal bond grindstone portion is composed of a plurality of grindstone layers including abrasive grains having different particle diameters. It is characterized by.

  The configuration of the sixth rotating grindstone of the present invention is characterized in that, in the fifth configuration, the outer peripheral end surface of the metal bond grindstone portion has a groove portion extending in the circumferential direction for each grindstone layer.

  According to the present invention, there is provided a rotating grindstone in which a metal bond grindstone portion suitable for rough polishing and a resin bond grindstone portion suitable for mirror polishing are coaxially laminated. Can be performed continuously from rough polishing to mirror polishing with a single rotating grindstone. As a result, the end face processing of the quartz wafer is made more efficient, and the cost can be reduced. Further, according to the polishing method of the crystal wafer end face of the present invention, the crystal wafer end face is polished by the metal bond grindstone and the resin bond grindstone, and the polishing using the free abrasive slurry is not performed. .

It is the whole and partial perspective view of the rotating grindstone in this Embodiment. It is the whole and a partial sectional view of a rotating grindstone in this embodiment. It is a figure which shows typically the end surface process using the rotary grindstone in this Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, this embodiment does not limit the technical scope of the present invention.

  1 and 2 are diagrams showing a configuration of a rotating grindstone according to an embodiment of the present invention. FIG. 1 is an overall and partial perspective view of the rotating grindstone, and FIG. 2 is an entire and partial sectional view of the rotating grindstone. is there.

  The rotating grindstone 10 includes two disk plates 11 and 12 that can be connected and fixed coaxially, a metal bond grindstone portion 13 in which abrasive grains are bonded with metal bonds, and a resin bond grindstone portion 14 in which abrasive grains are bonded with resin bonds. As shown in FIG. 1B, the metal bond grindstone portion 13 is joined to the outer peripheral surface of the disc plate 11, and as shown in FIG. 1A, the resin bond grindstone portion 14 is a disc plate. 12 are joined to the outer peripheral surface. The metal bond grindstone portion 13 and the resin bond grindstone portion 14 are joined to the outer peripheral surfaces of the disc plate 11 and the disc plate 12 with an adhesive, respectively. The resin bond grindstone portion 14 may be joined to the outer peripheral surface of the disk plate 11, and the metal bond grindstone portion 13 may be joined to the outer peripheral surface of the disc plate 12. The disc plates 11 and 12 are made of a metal such as aluminum or stainless steel.

  The disk plate 11 has a first through hole 11a on the rotation center axis and a protruding portion 11b that surrounds the first through hole 11a and protrudes in the axial direction. The disk plate 12 has a second through-hole 12a on the rotation center axis, and the second through-hole 12a is shaped to match the outer peripheral shape of the protrusion 11b of the first disk plate, and the protrusion As shown in FIG. 1 (c), they are fitted to the portion 11b, and both are overlapped on the same axis and connected and fixed by fixing means such as screws and screws. The disk plates 11 and 12 are provided with screw holes 11c and 12c at positions where they overlap each other when overlapped.

  Thereby, since the disk plates 11 and 12 are integrated coaxially, both the grindstone portions 13 and 14 are also coaxially arranged, and the alliance is also provided when polishing is transferred from the metal bond grindstone portion 13 to the resin bond grindstone portion 14. Adjustment (axis alignment) is unnecessary, machining time can be shortened, and high machining accuracy can be secured.

  As shown in FIG. 1 (c), the resin bond grindstone portion 14 is disposed so as to be laminated in the axial direction with the metal bond grindstone portion 13 by connecting the two disk plates 11 and 12. As will be described later, the metal bond grindstone 13 has abrasive grains having a relatively large particle size (small count) for rough polishing, and the resin bond grindstone 14 performs mirror polishing (finishing). For having relatively small grain size (large count).

  In rough polishing, hard and brittle quartz wafers including the R-finishing of the end face are ground to a large extent. Therefore, metal bonds, which are hard binders suitable for shape processing, are preferred. Metals that combine metal bonds and abrasive grains with large grain sizes A bond grindstone 13 is used. Since there is little embedding of abrasive grains in metal bonds and clogging is less likely to occur, the frequency of wheel replacement can be reduced. In mirror polishing, it is preferable to use a soft binder suitable for fine processing, and a resin bond grindstone portion 14 in which a resin bond softer than a metal bond and abrasive grains having a small particle diameter are used. Further, in mirror processing of a quartz wafer, since a temperature during polishing is high, it is preferable to use a polyamide resin bond having higher heat resistance than a phenol resin bond.

  Since the disk plates 11 and 12 are connected and fixed in a replaceable manner with screws or screws (not shown), either the metal bond grindstone portion 13 or the resin bond grindstone portion 14 can be exchanged. In particular, the resin bond grindstone portion 14 has a faster wear rate and a shorter life than the metal bond grindstone portion 13, and therefore has a high replacement frequency. By connecting and fixing the disk plates 11 and 12 so that they can be exchanged, even if the metal bond grindstone part 13 and the resin bond grindstone part 14 having different exchange frequencies are laminated in a single layer, they can be exchanged according to their respective lifetimes. The grindstone can be used without waste.

  Further, the outer diameters of the metal bond grindstone portion 13 and the resin bond grindstone portion 14 are the same, but the ring width of the resin bond grindstone portion 14 is formed wider than the ring width of the metal bond grindstone portion 13. In accordance with the difference, the outer diameter of the disc plate 12 to which the resin bond grindstone portion 14 is joined is formed smaller than the outer diameter of the disc plate 11 to which the metal bond grindstone portion 13 is joined. That is, the disk plate 11 and the disk plate 12 having different outer diameters are integrated by being coaxially stacked and connected and fixed, and the resin bond grindstone portion 14 is formed on the outer peripheral surface of the disk plate 12 having a relatively small outer diameter. The metal bond grindstone 13 is joined to the outer peripheral surface of the disk plate 11 having a relatively long outer diameter. Since the resin bond grindstone 14 has a faster wear rate than the metal bond grindstone 13, the resin bond grindstone 14 is made wider than the ring width of the metal bond grindstone 13. Maintenance efficiency is improved, for example, the replacement frequency of 14 can be reduced. Of course, the ring widths of both the grindstone portions 13 and 14 may be the same. In that case, the outer diameters of the disk plates 11 and 12 may be the same.

  As shown in FIG. 2, the metal bond grindstone portion 13 and the resin bond grindstone portion 14 are each composed of a plurality of layers having different particle sizes in the axial direction. FIG. 2B is an enlarged view of a portion surrounded by a dotted line in FIG. In the example shown in FIG. 2B, the metal bond grindstone 13 is composed of three layers, for example, stacked in the order of # 400, # 800, and # 1200 from the bottom of the drawing. Moreover, the resin bond grindstone part 14 is comprised from two layers, for example, is laminated | stacked in order of # 1500 and # 3000 from the bottom of the drawing. Through the resin bond grindstone portion 14 and the metal bond grindstone portion 13, the grindstones are stacked in order from the smallest count to the largest count. The number of layers in both the grindstone portions 13 and 14 is arbitrary and can be designed as appropriate. However, in rough polishing in which a large amount of processing is generated, the burden on the grindstone is large, so that the metal bond grindstone portion as in this embodiment is used. It is preferable to subdivide the number of layers 13 to be larger than the number of layers of the resin bond grindstone 14.

  In the above combination example of particle diameters, for example, up to # 1500 can be formed as the metal bond grindstone 13. That is, the resin bond grindstone part 14 should just have at least 1 layer which has an abrasive grain with the smallest particle size suitable for mirror surface finishing. On the other hand, since the resin bond grindstone portion 14 has a high wear rate, a plurality of layers may be provided as in the above combination example from the viewpoint of replacement frequency.

  In addition, by setting the minimum particle size in the resin bond grindstone portion 14 to # 3000, the index Ra (arithmetic average roughness) indicating the surface roughness can be finished to about 1 to 3 nm, and cracks on the end face can be generated. And greatly contribute to the improvement of yield.

  A plurality of layers of metal bond grindstones 13 having different particle diameters are a mixture of abrasive grains (diamonds, CBN (regular crystal boron nitride), etc.), binders (metal bonds), and fillers for each layer. In the molding step, the mixture corresponding to each layer is poured into a mold in order, laminated and molded, and then the molded product is fired at a predetermined temperature. The blending amount and blending ratio of the abrasive grains, the binder and the filler can be adjusted as appropriate. Similarly to the metal bond grindstone 13, the resin bond grindstone 14 having a plurality of layers having different particle sizes also generates a mixture in which abrasive grains, binders (resin bonds), and fillers having respective particle sizes are mixed for each layer. In the molding process, the mixture corresponding to each layer is poured into a mold in order, laminated and molded, and then fired at a predetermined temperature. However, since the metal bond grindstone portion 13 and the resin bond grindstone 14 are different in predetermined production conditions such as the firing temperature, the metal bond grindstone portion 13 and the resin bond grindstone portion 14 are produced separately, as described above. Reference numerals 13 and 14 denote disk plates 11 and 12 that are connected to the outer peripheral surface and are coaxially stacked and fixed. Further, the plurality of layers of metal bond grindstones 14 may be formed separately up to the firing step, instead of being laminated in the molding process, and then each layer may be laminated and bonded with an adhesive or the like. Similarly, the resin bond grindstone portion 14 may be separately manufactured for each layer up to the firing step.

  Further, as shown in FIGS. 2B and 2C, a groove 20 extending in the circumferential direction is formed on the outer peripheral end face of each layer of the metal bond grindstone 13 and the resin bond grindstone 14. FIG. 2C is an enlarged cross-sectional view of the groove 20. The groove 20 is used for chamfering (R processing or C processing) of the end face of the crystal wafer, and dimensions such as depth, width, and angle are appropriately determined.

  Since the chamfering groove 20 is formed in each layer of the resin bond grindstone 14, the chamfered portion of the crystal wafer end face can be mirror-polished by the grindstone without using the free abrasive slurry. The generation of cracks can be prevented.

  As described above, in the present embodiment, the metal bond grindstone portion 13 and the resin bond grindstone portion 14 are laminated and integrated in order to shape-process (chamfer chamfering) the end surface of the hard and brittle crystal wafer and further polish the mirror surface. Using a single rotating grindstone, first, a shape (for example, R shape) is formed by rough grinding with a grindstone using a relatively large grain size abrasive and a hard bond metal bond, and then a continuous process. Thus, mirror finishing is performed by polishing with a grindstone using a relatively small grain size abrasive grain and a resin bond which is a soft binder.

  FIG. 3 is a diagram schematically showing end face processing using the rotating grindstone in the present embodiment. The rotating grindstone 10 is coaxially connected to a rotating shaft through a through hole 11a formed at the center of the disk plate 11, and this rotating shaft is operated by a driving source (not shown) such as a motor via a belt mechanism. By being driven, the rotating grindstone 10 rotates.

  As described above, each layer of the metal bond grindstone portion 13 and the resin bond grindstone portion 14 in the rotary grindstone 10 is laminated so that the grain size of the abrasive grains becomes finer in order from the lowermost layer to the upper layer. Polishing is performed by moving the quartz wafer to be polished in the direction of the rotation axis by a moving means (not shown) such as a screw mechanism, and bringing the end face of the quartz wafer into contact with the groove 20 on the outer peripheral surface of the rotating grindstone 10. First, polishing is performed by bringing the end face of the quartz wafer into contact with the lowermost layer (the grindstone layer having the largest grain size of the metal bond grindstone 13), and then polishing is sequentially performed on each layer adjacent to the stacking order from the lowermost layer. Finally, polishing is performed with the uppermost layer (the grindstone layer having the smallest grain size of the resin bond grindstone portion 14). In this way, rough polishing to mirror polishing can be performed in a coaxial polishing process using a single rotating grindstone, which significantly improves processing accuracy, including high roundness. Further, since the metal bond grindstone portion 13 and the resin bond grindstone portion 14 perform rough polishing to mirror polishing, polishing can be performed without using the free abrasive slurry, so that waste liquid treatment is also unnecessary. Furthermore, since the metal bond grindstone portion and the resin bond grindstone portion 14 are disposed on the same rotating shaft during the transition from the polishing by the metal bond grindstone portion 13 to the polishing by the resin bond grindstone portion 14, alignment adjustment is performed. Therefore, the polishing process time is greatly shortened and the processing accuracy including high roundness is greatly improved.

  The rotational speed and the number of steps (number of times of contact) of the grinding wheel in polishing in each layer are appropriately set to optimum values in consideration of various conditions such as the size of the crystal wafer and the cutting amount.

  The present invention is not limited to the above-described embodiment, and there are design changes within a range that does not depart from the gist including various modifications and corrections that can be conceived by those having ordinary knowledge in the field of the present invention. Of course, it is included in the present invention.

  10: Rotating whetstone, 11: Disk plate, 11a: First through hole, 11b: Projection, 11c: Screw hole, 12: Disk plate, 12a: Second through hole, 12c: Screw hole, 13: Metal bond Grinding wheel, 14: Resin bond grinding wheel, 20: Groove

Claims (6)

In a rotating grindstone for polishing the end face of a quartz wafer,
An annular metal bond whetstone with abrasive grains bonded with metal bonds;
An annular resin bond grindstone unit with abrasive grains bonded with resin bonds,
The metal bond grindstone portion and the resin bond grindstone portion are coaxially laminated and fixed ,
The rotating grindstone is characterized in that an annular width of the resin bond grindstone portion is wider than an annular width of the metal bond grindstone portion . In claim 1,
A first disk plate having a first through-hole in the rotation center axis, and a second disk plate having a second through-hole in the rotation center axis and connected and fixed coaxially to the first disk plate. A disk plate,
The rotating grindstone is characterized in that the metal bond grindstone portion and the resin bond grindstone portion are joined to either one of the first disc plate and the second disc plate and the other outer peripheral surface, respectively. In claim 2,
The first disc plate has a protrusion surrounding the first through hole, and the second through hole of the second disc plate can be fitted into the protrusion. Whetstone. In any one of Claims 1 thru | or 3,
The rotating grindstone is characterized in that each of the outer peripheral end surfaces of the metal bond grindstone and / or the resin bond grindstone has grooves extending in the circumferential direction. In any one of Claims 1 thru | or 4,
An outer peripheral end face of the metal bond grindstone portion is composed of a plurality of grindstone layers including abrasive grains having different particle diameters. In claim 5,
The said metal bond grindstone part has a groove part extended in the circumferential direction for every grindstone layer, The rotary grindstone characterized by the above-mentioned.

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