JP2009006407A - Thin edge grinding wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin edge grinding wheel capable of performing high quality machining by suppressing a decrease of width of an abrasive grain layer, while preventing clogging, etc. due to adhesion of chips to the abrasive grain layer, and suppressing generation of burrs, even when a workpiece is especially constituted of a metal lead frame, plating and electrodes arranged in the resin. <P>SOLUTION: This thin edge grinding wheel is provided with the circular thin plate shaped abrasive grain layer 1 constituted by dispersing abrasive grains 4 in a metal plating phase 3. A coating layer 2 made of TiN is coated on a side surface 1A of the abrasive grain layer 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin blade grindstone used for cutting and grooving various electronic material parts such as semiconductor devices.

As this type of thin-blade grindstone, for example, Patent Document 1 has an annular flat plate-shaped grindstone main body in which abrasive grains are dispersedly arranged in a metal binder phase, and at least in the cutting action region of this grindstone main body, the thickness direction An electroformed thin blade grindstone in which the protruding amount of the abrasive grains from the surface of the metal bonding layer on the side facing the steel sheet is 1/4 or less of the average grain diameter of the abrasive grains has been proposed, and at least in this cutting action region, the thickness direction It is described that a high concentration layer having a higher concentration of abrasive grains than that of the intermediate portion is provided at both ends. Also, in Patent Document 2, an annular cutting edge portion is a central electrocast abrasive layer having a low degree of concentration in which abrasive grains are fixed by plating, and an outer electroformed abrasive grain having a high degree of concentration formed on both sides thereof. In addition, Patent Document 3 discloses an electrodeposition blade formed by electrodepositing abrasive grains with a base metal, and the surface of the base metal is coated with diamond-like carbon. There has also been proposed a coating layer formed so as to be thinner than the height of the abrasive grains protruding from the base metal.
JP 2004-136431 A JP 2002-331464 A JP 2000-144477 A

  By the way, when an electronic material part or the like is cut into individual pieces by using such a thin blade grindstone, the electronic material part which is a workpiece to be cut is particularly QFN (quad flat non-leaded package) or IrDA (Infrared Data Communication Association). ) Cut when metal parts such as Cu, etc., highly ductile lead frames, plating, electrodes, etc. are arranged at intervals in the molding resin, such as standard light transmission modules or LED works. There is a problem in that metal burrs such as lead frames and electrodes are likely to be generated in the feed direction and rotation direction (downward direction) of the thin blade grindstone.

  In this regard, in the thin-blade grindstone described in Patent Document 1, as described above, by providing high concentration layers on both ends in the thickness direction, that is, on both sides of the abrasive grain layer, in the cutting action region of the abrasive grain layer. By making it difficult for the wear to progress on both side surfaces and for the grindstone to wear while maintaining its initial shape, burrs are hardly formed. Moreover, in the thin blade grindstone of patent document 2, an annular recessed part is formed in the width direction center part of the outer periphery of an annular cutting blade part by wearing a center electroformed abrasive grain layer by dressing or use, and this annular recessed part In the thin blade grindstone described in Patent Documents 1 and 2, the side surface remains exposed with a metallic binder phase due to nickel plating or the like. For this reason, chips generated during processing are likely to adhere and cause clogging, the resistance increases, and the grindstone may become hot during processing to cause seizure.

  However, in the thin blade grindstone described in Patent Document 3, the friction coefficient of diamond-like carbon coated on the surface of the base metal, that is, the side surface of the abrasive grain layer is small, so that clogging on the side surface is prevented. At the same time, the resistance during processing can be reduced, but on the other hand, with such a coating layer made of diamond-like carbon, the wear resistance on both side surfaces of the abrasive layer is sufficiently increased with respect to the central portion in the thickness direction. The edge of the side outer peripheral edge of the abrasive grain layer including this coating layer is rounded so that the abrasive grain layer is thinned, and the metal part is spread to the rounded outer peripheral edge. As a result, metal burrs are easily generated. In addition, since the abrasive layer is thinned in this way, a large difference occurs in the cutting width on the front and back surfaces of the cut workpiece, or a corner chip occurs in the ridge line portion between the front and back surfaces and the cutting surface, resulting in processing quality. May be damaged. Moreover, such a diamond-like carbon coating layer is easily peeled off by heat generated during processing, and it is difficult to maintain the effects of preventing clogging and reducing resistance over a long period of time. It is also difficult to improve its own rigidity.

  The present invention has been made under such a background, and suppresses the width thinning of the abrasive layer while preventing clogging or the like due to adhesion of chips to the abrasive layer, and in particular, the workpiece is in the resin as described above. An object of the present invention is to provide a thin blade grindstone capable of performing high-quality processing while suppressing the occurrence of burrs, etc. even when a metal lead frame, plating, electrodes, and the like are disposed on the surface.

  In order to solve the above-described problems and achieve such an object, the present invention includes a circular thin plate-like abrasive grain layer formed by dispersing abrasive grains in a metal plating phase, A coating layer made of TiN is coated.

  In the thin blade whetstone configured in this way, the coating layer coated on the side surface of the abrasive layer is made of TiN having high hardness and high wear resistance. The edge shape of the outer peripheral edge of the side surface can be maintained without being promoted, and the abrasive grain layer is prevented from thinning so that the edge is rounded. Occurrence of burrs, differences in the cutting widths of the front and back surfaces, or chipped corners of the workpiece can be suppressed. In addition, since such a hard coating layer is coated on the side surface, the rigidity and strength of the grindstone itself can be improved. Therefore, even if the thickness of the abrasive layer is reduced, straightness is ensured and high. Precision machining can be performed. For example, the cutting allowance can be made as small as possible to improve the product yield, and even when the oscillator can be grooved at a narrow pitch, this can be dealt with reliably. It becomes possible to do. On the other hand, the coating layer made of TiN does not easily peel from the metal plating phase in the abrasive layer, can maintain the above-mentioned edge shape over a long period of time, and chip adhesion is Since it is low, the occurrence of clogging or the like can be prevented, and an increase in resistance or seizure during processing can be prevented.

  Here, the coating layer may be covered over the entire circular side surface of the abrasive layer, but for example, an annular thin plate-like shape that is sandwiched between a pair of flanges and used for processing. In the thin-blade grindstone, if the coating layer is coated at least on the outer peripheral side of the flange, the abrasive layer is reliably supported via the high-hardness coating layer as described above to ensure straightness. Therefore, it is only necessary that this coating layer is coated with a width of 1/2 or more of the width in the radial direction of the abrasive grain layer from the outer periphery of the abrasive grain layer. However, if the coating thickness is so thick that the abrasive grains dispersed from the abrasive layer and protruding from the side surface are buried, there is a risk of increasing resistance during processing and deterioration of sharpness. The coating layer is preferably coated with a thickness of 1/2 or less of the average grain size of the abrasive grains.

  On the other hand, in order to coat such a coating layer made of TiN, a CVD method in which coating is carried out by reacting with a reactive gas while holding a thin blade grindstone having an abrasive layer formed by a known method in a high-temperature furnace ( (Chemical vapor deposition method) It is also possible, but in such a CVD method, the metal plating phase of the abrasive layer may change in quality due to high temperature and the rigidity and strength of the abrasive layer itself may be impaired. The coating layer is preferably coated by a PVD method (physical vapor deposition method) represented by an ion plating method or a sputtering method.

  Thus, according to the thin-blade grindstone of the present invention, the width of the abrasive layer can be prevented and the edge shape at the side outer peripheral edge can be maintained over a long period of time, even if the workpiece has a metal part in the resin. Even if it has, it is possible to perform high-quality processing by preventing the generation of burrs and the like. In addition, since the coating layer made of TiN is difficult to peel off from the metal plating phase of the abrasive grain layer, such an effect can be achieved over a long period of time. On the other hand, chip adhesion can be suppressed. It is also possible to prevent clogging due to adhesion, increase in resistance accompanying this, and seizure.

  1 to 3 are schematic views showing an embodiment of the thin blade grindstone of the present invention. As shown in FIG. 1, the thin-blade grindstone of the present embodiment is an annular shape centered on the axis O and has a thin plate shape having a thickness of about 0.05 to 0.5 mm. And a coating layer 2 coated on the side surface 1A of the annular thin plate-like abrasive grain layer 1 and the inner diameter part 1B of the abrasive grain layer 1 is not shown in the drawing. While being inserted into the main shaft of the apparatus, the inner peripheral side portion including the coating layer 2 on both side surfaces 1A and 1A is attached to the main shaft by being sandwiched by a pair of flanges or the like. Then, by rotating around the axis O and feeding it in a direction perpendicular to the axis O, the outer peripheral edge cuts an electronic component such as the above-described QFN or IrDA standard light transmission module or LED work. Used for ultra-precision machining such as grooving.

  The abrasive grain layer 1 is obtained by uniformly dispersing superabrasive grains 4 such as diamond and cBN in a metal plating phase 3 such as Ni, and has a predetermined thickness while incorporating the superabrasive grains 4 on a base metal. After the metal plating phase 3 is deposited, the metal plating phase 3 is formed by a well-known electroforming method by peeling from the base metal and making the side surfaces 1A sharp. On the other hand, in the present embodiment, the coating layer 2 is formed on both side surfaces 1A and 1A of the thus formed abrasive grain layer 1 by ½ the radial width W of the abrasive grain layer 1 from the outer periphery of the abrasive grain layer 1. The above-mentioned constant width X is coated with a substantially constant thickness t equal to or less than 1/2 of the average grain size of the superabrasive grains 4, and is constituted by coating TiN by the PVD method. . In addition, the coating layer 2 made of TiN thus coated has the width X and the thickness t substantially equal to each other on both side surfaces 1A, 1A of the abrasive grain layer 1.

More specifically, the coating layer 2 is coated by an arc ion plating method. For example, the abrasive layer 1 formed as described above is masked except for a portion where the coating layer 2 is to be formed. After holding in the chamber and creating a vacuum of 1 × 10 ^{−4 to} 3 × 10 ⁻⁵ Pa, first, high-frequency plasma is generated at an output of 300 W while introducing Ar gas, and −500 V is applied to the abrasive layer 1. The surface is cleaned by applying a DC bias voltage. Next, after applying a pulse bias voltage of −10 kV to the abrasive grain layer 1, nitrogen gas is introduced into the vacuum chamber at a flow rate of 100 to 120 (SCCM) to generate a high-frequency plasma and / or after generating Ti alloy. The target is evaporated by arc discharge with an arc current of about 80 A, and is coated by vapor deposition in a processing time of about 120 minutes, for example, so as to achieve a predetermined thickness t while adjusting the applied pulse bias voltage. .

  In the thin blade grindstone thus coated with the coating layer 2, the thickness t of the coating layer 2 is ½ or less of the average grain size of the superabrasive grains 4. The superabrasive grains 4 that have protruded from 1A by more than ½ of the average particle diameter also protrude from the surface of the coating layer 2. Further, after the coating layer 2 is coated, the inner diameter and outer diameter of the thin-blade grindstone are formed to a predetermined diameter. At this time, the coating layer 2 is removed at the outer peripheral edge of the abrasive grain layer 1 and the superabrasive as shown in FIG. While the grains 4 are projected, the outer peripheral edge of the side surface of the grindstone including the coating layer 2 is formed to have a substantially right-angled edge shape.

  Therefore, in the thin blade grindstone of this embodiment formed in this way, the coating layer 2 made of TiN coated on the side surface 1A of the abrasive grain layer 1 has higher hardness than the metal plating phase 3 of the abrasive grain layer 1. Since the wear resistance is high, even when the abrasive grain layer 1 is worn, the abrasive grain layer 1 is wide so that the outer peripheral edges of the side surfaces 1A and 1A are worn away and the edges are rounded in cross section. It will not fade, and will wear out substantially uniformly while maintaining this edge shape that is substantially perpendicular to the cross section. For this reason, since cutting and grooving of a workpiece can be performed while maintaining the sharpness of the edge, according to the thin blade whetstone having the above-described configuration, even if the workpiece is a highly ductile metal such as Cu in the mold resin Even if it includes lead frames, electrodes, and plating, it is possible to prevent the occurrence of such metal burrs, reduce the difference in cutting width between the front and back surfaces of the cut workpiece, It is possible to prevent the occurrence of corner chipping at the intersecting ridge line portion with the cut surface, and high-quality processing can be achieved.

  Further, such a coating layer 2 made of TiN is not easily peeled off by heat generated during processing like a conventional coating layer made of diamond-like carbon, and is stable over a long period of time. The above effects can be achieved. On the other hand, the TiN coating layer 2 has less chip adhesion compared to, for example, an abrasive layer with a metal plating phase 3 such as Ni exposed, thus preventing clogging due to chips and the like. It is possible to promote a reduction in resistance at the time, and it is possible to maintain a sharp sharpness over a long period of time by suppressing heat generation during processing and seizure associated therewith.

  Furthermore, by coating the side surface 1A with the coating layer 2 made of hard TiN in this way, in this embodiment, even if the thickness of the thin blade grindstone is reduced, sufficient rigidity and strength can be secured, This maintains the straightness of the thin-edged grindstone during cutting and grooving, and achieves high machining accuracy, while reducing the cutting allowance as much as possible to improve product yield and ensuring grooving at narrow pitches. It is possible to respond. In addition, the abrasive layer 1 is thus coated with the hard and highly wear-resistant coating layer 2 made of TiN, whereby the wear resistance of the grindstone itself can be improved and the life can be extended.

  Furthermore, in the present embodiment, the coating layer 2 is coated from the outer periphery of the abrasive grain layer 1 with a width X that is ½ or more of the radial width W of the abrasive grain layer 1, and a thin blade grindstone is formed by a pair of flanges. When sandwiched, the coating layers 2 and 2 on both side surfaces 1A and 1A of the abrasive grain layer 1 are sandwiched between the inner peripheral portions of the coating layer 2 and the flange. For this reason, cutting and grooving can be performed with these flanges supporting the outer periphery of the thin-blade grindstone through the hard coating layers 2 and 2, and the rigidity and strength of the grindstone itself are ensured as described above. In combination with this, it is possible to further improve the straightness and process with high accuracy.

  The width X only needs to be in such a range that the flange sandwiches the coating layer 2 as described above. For example, the width X is equal to the width W of the side surface 1A of the annular abrasive grain layer 1, that is, The entire surface of the side surface 1A may be configured to be coated with the coating layer 2. However, in the present embodiment, the thin blade whetstone is sandwiched between the pair of flanges as described above. For example, the present invention is applied to a thin blade whetstone with a hub in which the abrasive grain layer 1 is formed on the side surface of an annular base metal. It is also possible to apply.

  On the other hand, in the present embodiment, the coating layer 2 has a thickness t that is 1/2 or less of the average grain size of the superabrasive grains 4, and the average grain size is measured from both side surfaces 1A of the abrasive grain layer 1 as described above. The superabrasive grains 4 protruding more than 1/2 are projected from the surface of the coating layer 2 as they are, and for this reason, a slight gap is formed between the processing wall surface during cutting and grooving and the surface of the coating layer 2. But clearance can be secured. Accordingly, resistance during processing can be further reduced, and chips can be smoothly discharged through this clearance, so that occurrence of clogging and the like can be prevented more reliably. However, if the thickness t of the coating layer 2 is too small, it may be difficult to ensure rigidity and strength. Therefore, the thickness t is 1/5 or more of the average grain size of the abrasive grains, or 0.5 μm or more. It is desirable that the thickness be 1.0 μm or more.

  Furthermore, in the present embodiment, the coating layer 2 made of TiN is coated by the PVD method, and the abrasive layer 1 is not exposed to a high temperature when the coating layer 2 is coated. The metal plating phase 3 of the abrasive grain layer 1 is not altered by high temperature, and the rigidity and strength of the abrasive grain layer 1 itself are not impaired. Accordingly, it is possible to prevent a situation in which the rigidity and strength of the thin blade grinding wheel as a whole are impaired despite the coating layer 2 being coated, and even more reliably even if the grinding stone thickness is reduced. High-precision machining is possible, and cutting allowance can be reduced and grooving at a narrow pitch can be achieved.

  Hereinafter, the thin-blade grindstone of the present invention will be described with more specific examples. In this example, first, an abrasive grain layer 1 having an outer diameter of 58 mm, an inner diameter of 40 mm, and a thickness of 0.15 mm in which diamond superabrasive grains having an average grain diameter of 25 μm (grain size # 600) are uniformly dispersed in the Ni plating phase at a concentration of 100. Was manufactured as a base blade. Next, a coating layer 2 made of TiN having a thickness t of 10 μm, 5 μm, and 15 μm is formed on each side surface 1A, 1A of the abrasive layer 1 of the base blade by the PVD method using the arc ion plating method under the conditions described above. Three thin blade grinding wheels according to the present invention were manufactured. These are referred to as Examples 1 to 3 in the order of the thickness t. In Examples 1 to 3, the width X of the coating layer 2 from the outer periphery of the grindstone was 4.5 mm which is 1/2 of the width W of the abrasive grain layer 1 = 9 mm.

Next, the glass epoxy resin substrate having a width of 80 mm, a length of 200 mm, and a thickness of 1.0 mm is cut using the thin blade grindstone of the base blade not coated with the coating layer 2 as Examples 1 to 3 and a comparative example. The difference in the cutting width between the front and back surfaces of the workpiece at the cutting lengths of 100 m, 500 m, and 1000 m was measured, and the presence or absence of corner chipping was confirmed with a tool microscope. The cutting device is model number AWD-100A manufactured by Tokyo Seimitsu Co., Ltd., and each thin blade grindstone is sandwiched between its main shafts by a flange having an outer diameter of 52 mm, and is cut at a main shaft rotation speed of 30000 min ⁻¹ and a feed rate of 100 mm / sec. Processing was performed. The results are shown in Table 1 for the difference in cutting width and in Table 2 for the corner chipping.

  From the results of Tables 1 and 2, the thin blade whetstone of the base blade as a comparative example is larger than any of the thin blade whetstones of Examples 1 to 3 in both the cutting width difference and the corner chipping. There was a tendency for the increase to become more pronounced with increasing length. On the other hand, in the thin-blade grindstones of Examples 1 to 3, both the difference in cutting width and the corner chip are generally smaller than those of the base blade, and especially the difference in cutting width tends to increase up to a cutting length of 500 m. From this, it can be seen that although it is slightly increased in Example 2 up to 1000 m, it is stable at a substantially constant size.

  Further, when these Examples 1 to 3 are compared with each other, the difference in cutting width was not significantly different in Examples 1 and 3, whereas in Example 2 in which the thickness t of the coating layer 2 was reduced. These tend to be larger than those of Examples 1 and 3. In addition, as for the corner chipping, in Example 3, although a small chipping was observed although the quality was not deteriorated from the cutting length of 100 m, the thickness t of the coating layer 2 was 1 / (average particle diameter of the abrasive grains 4). In Examples 1 and 2 which were set to 2 or less, a cutting length of 1000 m was not recognized.

  Next, in the same manner as described above, diamond superabrasive grains having an average grain size of 18.5 μm (grain size # 700) were uniformly dispersed in the Ni plating layer with a concentration of 100, an outer diameter of 58 mm, an inner diameter of 40 mm, and a thickness of 0.22 mm. The abrasive layer 1 of the base blade is manufactured as a base blade, and the thickness t is set to 9 μm and 5 μm on both side surfaces 1A and 1A of the abrasive layer 1 of this base blade by the PVD method using the arc ion plating method under the same conditions as described above. The coating layer 2 made of TiN having a thickness of 13 μm was coated to produce three types of thin blade grinding wheels according to the present invention. Let these be Examples 4-6 in order of the said thickness t. In Examples 4 to 6 as well, the width X of the coating layer 2 from the outer periphery of the grindstone was 4.5 mm, which is 1/2 of the width W of the abrasive grain layer 1 = 9 mm, as in Examples 1 to 3.

And the glass-epoxy resin board | substrate of width 60mm, length 120mm, and thickness 0.2mm with the thin blade grindstone of these Examples 4-6 and the thin blade grindstone of the said base blade which does not coat | cover the coating layer 2 as a comparative example The workpiece is cut with a resist resin with a thickness of 0.8 mm on the surface and Cu metal plating with a thickness of 0.02 mm on the back surface. The size of burrs generated in the rotation direction was also measured at cutting lengths of 100 m, 500 m, and 1000 m. The results are shown in Table 3 for the difference in cutting width and in Table 4 for the size of burrs. At this time, the spindle rotation speed was 20000 min ⁻¹ , and the feed rate was 70 mm / sec.

  From the results in Table 3, the difference in the cutting width was the same as in the case of the base blades in Examples 1 to 3 and the comparative example, except that the difference at the cutting length of 100 m in Example 5 was large. The difference is suppressed small in Examples 4 to 6 in which the coating layer 2 was coated with respect to the base blade not coated with the layer 2, and in Examples 4 to 6, the coating layer 2 was thick. Thus, the difference was smaller than in Example 5 where the coating layer 2 was thin. Further, regarding the increase in the difference with respect to the increase in the cutting length, the difference in the cutting width increases as the cutting length increases in the base blade, whereas in Examples 4 to 6, the cutting length tends to be stable at 500 m or more. Presents.

  Further, from the results of Table 4, the size of the burr is also suppressed to be small in Examples 4 to 6 in which the coating layer 2 is coated on the base blade not coated with the coating layer 2. The thickness t of the coating layer 2 was small in Examples 4 and 5 where the thickness t of the coating layer 2 was 1/2 or less of the average particle diameter of the abrasive grains 4, and in the thicker Example 6, the thickness t tended to be slightly larger. Note that the size of the burr itself, including the base blade, tended to be almost constant regardless of the cutting length.

It is a side view which shows one Embodiment of this invention. It is ZZ sectional drawing in FIG. It is an enlarged view which shows the outer periphery part periphery of sectional drawing shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Abrasive grain layer 1A Side surface of abrasive grain layer 1 2 Coating layer 3 Metal plating phase 4 Super abrasive grain (abrasive grain)
W Radial width of abrasive layer 1 X Radial width of coating layer 2 t Thickness of coating layer 2

Claims (4)

  A thin-blade grindstone comprising a circular thin plate-like abrasive grain layer in which abrasive grains are dispersed in a metal plating phase, and a coating layer made of TiN is coated on a side surface of the abrasive grain layer.   2. The thin-blade grindstone according to claim 1, wherein the coating layer is coated with a width of ½ or more of a radial width of the abrasive grain layer from an outer periphery of the abrasive grain layer.   The thin-blade grindstone according to claim 1 or 2, wherein the coating layer is coated with a thickness of ½ or less of an average particle diameter of the abrasive grains.   The thin-blade grindstone according to any one of claims 1 to 3, wherein the coating layer is coated by a PVD method.

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