JP2022094578A - Electroformed grindstone - Google Patents

Abstract

To provide an electroformed grindstone that can promote self-sharpening while suppressing a decrease in strength.SOLUTION: An electroformed grindstone has a grindstone part including abrasive grains and a binder for fixing the abrasive grains. The binder is composed of a Ni-Co alloy and contains a fluorine-based resin. The Co content in the binder may be 5 wt.% or more and 30.2 wt.% or less. The content of the fluorine-based resin in the binder may be 3 vol% or more and less than 40 vol%.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electroformed grindstone used for cutting a workpiece or the like.

By dividing a wafer in which a plurality of devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are formed, a plurality of device chips including the devices are manufactured. Further, a package substrate can be obtained by mounting a plurality of device chips on a predetermined substrate and then coating the mounted device chips with a sealing material (mold resin) made of a resin. By dividing the package substrate, a packaged device including a plurality of packaged device chips is manufactured. Device chips and packaged devices are incorporated into various electronic devices such as mobile phones and personal computers.

A cutting device is used when dividing a workpiece such as a wafer or a package substrate. The cutting device includes a chuck table for holding the workpiece and a cutting unit for cutting the workpiece. The cutting unit includes a spindle that functions as a rotation axis, and a cutting blade is attached to the tip of the spindle.

As the cutting blade, an electroformed grindstone including an annular grindstone portion (cutting blade) can be used. For example, the grindstone portion of an electroformed grindstone is formed by fixing abrasive grains made of diamond with a layer made of nickel (Ni plating layer) formed by electrodeposition (see Patent Document 1). The work piece is held by the chuck table of the cutting device, and the work piece is cut and divided by cutting the grindstone portion into the work piece while rotating the electroformed grindstone (see Patent Document 2).

When the electroformed grindstone is cut into the work piece, the abrasive grains exposed from the Ni plating layer come into contact with the work piece and cut the work piece. When the cutting of the workpiece by the electroformed grindstone is continued for a certain period of time, the Ni plating layer is worn and the exposed abrasive grains fall off, and the abrasive grains embedded inside the Ni plating layer are newly replaced. Exposed to. This phenomenon is called a self-generated blade, and the self-generated blade maintains the sharpness of the electroformed grindstone.

However, the Ni-plated layer has a strong force to hold the abrasive grains, and even if the Ni-plated layer wears, the abrasive grains do not easily fall off. Therefore, the electroformed grindstone in which the abrasive grains are fixed by the Ni plating layer has a characteristic that spontaneous blade generation is unlikely to occur. When cutting of the workpiece is continued without spontaneous blade generation occurring at an appropriate frequency, the tip of the abrasive grains exposed from the Ni plating layer is worn and deformed due to contact with the workpiece. .. As a result, the pressure (machining load) applied to the workpiece during cutting increases, and machining defects are likely to occur.

Therefore, a method has been proposed in which the Ni-plated layer of the electroformed grindstone contains a fluororesin to control the falling off of the abrasive grains (see Patent Document 3). When the fluorine-based resin is dispersed in the Ni-plated layer, the abrasive grains are likely to fall off from the Ni-plated layer when the electroformed grindstone is cut into the workpiece, and the self-generated blade is promoted. As a result, the sharpness of the electroformed grindstone is maintained, and the occurrence of processing defects is suppressed.

Japanese Unexamined Patent Publication No. 2000-87282 Japanese Unexamined Patent Publication No. 2005-51094 Japanese Unexamined Patent Publication No. 2009-119559

When the fluorine-based resin is dispersed in the Ni-plated layer, the self-generated blade is promoted, but the hardness and rigidity of the Ni-plated layer are lowered, and the electroformed grindstone is liable to warp. When cutting is performed using such an electroformed grindstone, the electroformed grindstone may be chipped or cracked, or the electroformed grindstone may meander when cutting the workpiece, and an unintended region of the workpiece may be cut. It may be done. That is, when the Ni plating layer contains a fluorine-based resin, there is a problem that the strength of the electroformed grindstone is lowered, and the electroformed grindstone is liable to be damaged or defective in processing.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an electroformed grindstone capable of promoting spontaneous blade generation while suppressing a decrease in strength.

According to one aspect of the present invention, an electroformed grindstone including an abrasive grain and a binder for fixing the abrasive grain is provided, and the binder is a Ni—Co alloy and contains a fluororesin. Is provided.

It should be noted that the content of Co in the binder is preferably 5 wt% or more and 30.2 wt% or less. Further, preferably, the content of the fluororesin in the binder is 3 vol% or more and less than 40 vol%. Further, preferably, the average particle size of the abrasive grains is 1 μm or more and 80 μm or less, and the average particle size of the fluororesin is 0.1 μm or more and 20 μm or less.

Further, preferably, the electroformed grindstone includes an annular base and an annular grindstone portion formed along the outer peripheral edge of the base. Further, preferably, the electroformed grindstone is composed of the annular grindstone portion.

In the electroformed grindstone according to one aspect of the present invention, the abrasive grains are fixed by a binder made of a Ni—Co alloy and containing a fluororesin. The strength of the electroformed grindstone is maintained by the binder made of a Ni—Co alloy having high hardness and high rigidity, and the falling off of the abrasive grains is accelerated by the fluororesin. As a result, it is possible to suppress the decrease in the strength of the electroformed grindstone and promote the self-generated blade, and it is possible to prevent the electroformed grindstone from being damaged and processing defects.

FIG. 1A is a perspective view showing a hub type electroformed grindstone, and FIG. 1B is a perspective view showing a washer type electroformed grindstone. It is a perspective view which shows the cutting apparatus. It is a perspective view which shows the cutting unit. It is an enlarged sectional view which shows the tip part of the grindstone part. It is a partial sectional front view which shows the manufacturing apparatus which manufactures a hub type electroformed grindstone. FIG. 6A is a cross-sectional view showing an annular base on which a Ni—Co alloy plating layer is formed, and FIG. 6B is a cross-sectional view showing an annular base on which the outer peripheral portion is etched. It is a partial cross-sectional front view which shows the manufacturing apparatus which manufactures a washer type electroformed grindstone. FIG. 8 (A) is a cross-sectional view showing a disk-shaped base on which a Ni—Co alloy plating layer is formed, and FIG. 8 (B) shows a Ni—Co alloy plating layer separated from the disk-shaped base. It is sectional drawing which shows. FIG. 9A is a graph showing the relationship between the Co content and the size of the warp of the electroformed grindstone, and FIG. 9B is a graph showing the relationship between the Co content and the hardness of the electroformed grindstone. Yes, FIG. 9C is a graph showing the relationship between the Co content and the rigidity of the electroformed grindstone. FIG. 10A is a graph showing the relationship between the content of the fluororesin and the rigidity of the electroformed grindstone, and FIG. 10B is a graph showing the relationship between the content of the fluororesin and the maximum chipping size. be.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, a configuration example of the electroformed grindstone according to the present embodiment will be described. The electroformed grindstone according to this embodiment can be used as a cutting blade or the like for cutting a workpiece.

FIG. 1A is a perspective view showing a hub type electroformed grindstone 11. The electroformed grindstone 11 includes an annular base 13 and an annular grindstone portion 15 formed along the outer peripheral edge of the base 13.

For example, the base 13 is made of a metal containing aluminum as a main component, and includes a front surface 13a and a back surface 13b. In the central portion of the base 13, a columnar through hole 13c extending from the front surface 13a to the back surface 13b of the base 13 is provided so as to penetrate the base 13 in the thickness direction. Further, around the through hole 13c, an annular convex portion 13d protruding from the surface 13a of the base 13 in the thickness direction of the base 13 is provided.

On the back surface 13b side of the base 13, an annular grindstone portion 15 is provided along the outer peripheral edge of the base 13. The outer diameter of the grindstone portion 15 is larger than the outer diameter of the base 13, and the grindstone portion 15 is formed so as to protrude outward in the radial direction from the outer peripheral edge of the base 13.

FIG. 1B is a perspective view showing a washer type electroformed grindstone 21. The electroformed grindstone 21 is composed of only an annular grindstone portion 23. The grindstone portion 23 includes a front surface 23a and a back surface 23b. Further, in the central portion of the grindstone portion 23, a columnar through hole 23c extending from the front surface 23a to the back surface 23b of the grindstone portion 23 is provided so as to penetrate the grindstone portion 23 in the thickness direction.

For example, electroformed grindstones 11 and 21 are used as a cutting blade for cutting a workpiece. Specifically, the electroformed grindstone 11 is a hub-type cutting blade (hub blade) in which the grindstone portion 15 functions as an annular cutting blade. Further, the electroformed grindstone 21 is a washer-type cutting blade (washer blade) that functions as an annular cutting blade as a whole. The electroformed grindstones 11 and 21 are mounted on a cutting device to cut a workpiece.

FIG. 2 is a perspective view showing the cutting device 2. The cutting device 2 cuts the workpiece 31 using the electroformed grindstone 11 or the electroformed grindstone 21. In FIG. 3, the X-axis direction (machining feed direction, first horizontal direction, left-right direction) and the Y-axis direction (indexing feed direction, second horizontal direction, front-back direction) are directions perpendicular to each other. The Z-axis direction (vertical direction, vertical direction, height direction) is a direction perpendicular to the X-axis direction and the Y-axis direction.

The cutting device 2 includes a base 4 that supports or accommodates each component constituting the cutting device 2. A cover 6 that covers the upper surface side of the base 4 is provided on the upper side of the base 4. A space (machining chamber) for machining the workpiece 31 is formed inside the cover 6, and a cutting unit 8 for cutting the workpiece 31 is arranged in the machining chamber.

A ball screw type moving mechanism (not shown) is connected to the cutting unit 8. This moving mechanism moves the cutting unit 8 along the Y-axis direction and moves the cutting unit 8 up and down along the Z-axis direction. Further, the electroformed grindstone 11 (see FIG. 1 (A)) or the electroformed grindstone 21 (see FIG. 1 (B)) is mounted on the cutting unit 8. Hereinafter, as an example, a case where the electroformed grindstone 11 is mounted on the cutting unit 8 and the cutting device 2 processes the workpiece 31 using the electroformed grindstone 11 will be described.

FIG. 3 is a perspective view showing the cutting unit 8. The cutting unit 8 includes a housing 10 formed in a hollow columnar shape. The housing 10 houses a columnar spindle 12 arranged along the Y-axis direction. The tip end portion (one end side) of the spindle 12 is exposed to the outside of the housing 10. Further, a rotation drive source (not shown) such as a motor for rotating the spindle 12 is connected to the base end portion (other end side) of the spindle 12.

A mount 14 is fixed to the tip of the spindle 12. The mount 14 includes a disk-shaped flange portion 16 and a columnar support shaft (boss portion) 18 projecting from the central portion of the surface 16a of the flange portion 16. On the surface 16a side of the outer peripheral portion of the flange portion 16, an annular convex portion 16b protruding from the surface 16a is provided along the outer peripheral edge of the flange portion 16. The tip surface of the convex portion 16b is formed substantially parallel to the surface 16a. Further, a threaded portion 18a is formed on the outer peripheral surface of the support shaft 18.

An annular fixing nut 20 is mounted on the support shaft 18. A columnar opening 20a that penetrates the fixing nut 20 in the thickness direction is formed in the central portion of the fixing nut 20. A thread groove corresponding to the threaded portion 18a of the support shaft 18 is formed on the side surface (inner peripheral surface) of the fixing nut 20 exposed inside the opening 20a.

When the support shaft 18 is inserted into the through hole 13c of the base 13 included in the electroformed grindstone 11, the electroformed grindstone 11 is mounted on the tip end portion (mount 14) of the spindle 12. The convex portion 13d of the base 13 corresponds to a grip portion that is gripped when the electroformed grindstone 11 is mounted.

When the fixing nut 20 is tightened to the threaded portion 18a of the support shaft 18 with the electroformed grindstone 11 mounted on the mount 14, the electroformed grindstone 11 is formed by the tip surface of the convex portion 16b of the flange portion 16 and the fixing nut 20. Be pinched. As a result, the electroformed grindstone 11 is fixed to the tip end portion (mount 14) of the spindle 12. Then, the electric casting grindstone 11 rotates around a rotation axis substantially parallel to the Y-axis direction by the power transmitted from the rotation drive source via the spindle 12 and the mount 14.

As shown in FIG. 2, a chuck table (holding table) 22 for holding the workpiece 31 is provided below the cutting unit 8. The upper surface of the chuck table 22 is a flat surface substantially parallel to the X-axis direction and the Y-axis direction, and constitutes a holding surface 22a for holding the workpiece 31. The holding surface 22a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve (not shown), or the like formed inside the chuck table 22.

A ball screw type moving mechanism (not shown) and a rotary drive source such as a motor are connected to the chuck table 22. The moving mechanism moves the chuck table 22 along the X-axis direction. Further, the rotation drive source rotates the chuck table 22 around a rotation axis substantially parallel to the Z-axis direction.

A cassette elevator 24 configured to be able to move up and down along the Z-axis direction is provided at a corner portion on the front side of the base 4. A cassette 26 capable of accommodating the workpiece 31 is placed on the cassette elevator 24. The cassette elevator 24 adjusts the height of the cassette 26 so that the workpiece 31 can be carried out from the cassette 26 and the workpiece 31 can be appropriately carried into the cassette 26.

A transport mechanism (not shown) for transporting the workpiece 31 is provided in the vicinity of the cassette elevator 24. This transport mechanism carries out the workpiece 31 before machining from the cassette 26 and transports it on the chuck table 22, and also carries the workpiece 31 machined by the cutting unit 8 into the cassette 26.

A display unit (display unit, display device) 28 for displaying various information related to the cutting device 2 is provided on the front surface 6a side of the cover 6. The display unit 28 displays information (machining conditions, machining status, etc.) regarding the machining of the workpiece 31 and an image of the workpiece 31 held by the chuck table 22.

For example, the display unit 28 is composed of a touch panel type display. In this case, the display unit 28 serves as a user interface, and the operator can input information such as machining conditions to the cutting device 2 by touch operation of the display unit 28. That is, the display unit 28 also functions as an input unit (input unit, input device) for inputting information to the cutting device 2. However, the input unit may be provided separately from the display unit 28. For example, a keyboard, a mouse, or the like can be used as the input unit.

A control unit (control unit, control device) 30 for controlling the cutting device 2 is provided inside or outside the cutting device 2. The control unit 30 is connected to each component (cutting unit 8, chuck table 22, cassette elevator 24, display unit 28, etc.) constituting the cutting device 2, and is a control signal for controlling the operation of each component. To generate.

For example, the control unit 30 is configured by a computer. Specifically, the control unit 30 is a processing unit that performs processing such as calculations necessary for controlling the cutting device 2, and a storage unit that stores various information (data, programs, etc.) used for controlling the cutting device 2. And prepare. The processing unit includes a processor such as a CPU (Central Processing Unit). Further, the storage unit includes a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

The workpiece 31 housed in the cassette 26 is conveyed onto the chuck table 22 by the conveying mechanism. When the work piece 31 is placed on the chuck table 22 and the suction force (negative pressure) of the suction source is applied to the holding surface 22a, the work piece 31 is sucked and held by the chuck table 22. The workpiece 31 held by the chuck table 22 is cut by the electroformed grindstone 11 mounted on the cutting unit 8. Then, the workpiece 31 after processing is conveyed by the conveying mechanism and is accommodated in the cassette 26 again.

When cutting the workpiece 31 with the electroformed grindstone 11, first, the height of the cutting unit 8 (in the Z-axis direction) so that the lower end of the electroformed grindstone 11 is positioned below the upper surface of the workpiece 31. Position) is adjusted. Further, the position of the cutting unit 8 in the Y-axis direction is adjusted so that the electroformed grindstone 11 cuts into a desired position of the workpiece 31. In this state, when the chuck table 22 is moved along the X-axis direction while rotating the electroformed grindstone 11, the grindstone portion 15 (see FIG. 3) of the electroformed grindstone 11 cuts into the workpiece 31 and the workpiece is worked. 31 is cut.

Further, the cutting unit 8 includes a nozzle (not shown) for supplying a liquid (cutting fluid) such as pure water toward the electroformed grindstone 11 and the workpiece 31. During the cutting process, the cutting fluid is supplied to the electroformed grindstone 11 and the workpiece 31 via the nozzle. As a result, the electroformed grindstone 11 and the workpiece 31 are cooled, and the debris (cutting debris) generated by cutting is washed away.

There are no restrictions on the material, shape, structure, size, etc. of the workpiece 31 to be cut by the cutting device 2. For example, the workpiece 31 may be a wafer made of a semiconductor (Si, GaAs, InP, GaN, SiC, etc.), sapphire, glass, ceramics, resin, metal, or the like. Further, the workpiece 31 may be a package substrate such as a CSP (Chip Size Package) substrate or a QFN (Quad Flat Non-leaded package) substrate.

Further, although the case where the workpiece 31 is cut by the electroformed grindstone 11 has been described above, the cutting device 2 may also cut the workpiece 31 using the electroformed grindstone 21 (see FIG. 1 (B)). can. In this case, the electroformed grindstone 21 is attached to the cutting unit 8. Then, the electroformed grindstone 21 is rotated to cut into the workpiece 31, so that the workpiece 31 is cut.

FIG. 4 is an enlarged cross-sectional view showing the tip portions of the grindstone portions 15 and 23. The grindstone portions 15 and 23 each include an abrasive grain 41 and a binder (bonding material) 43 for fixing the abrasive grain 41, respectively. There is no limitation on the material and size of the abrasive grains 41. For example, by using an abrasive grain 41 made of diamond, cubic Boron Nitride (cBN) or the like and having an average particle size of 1 μm or more and 80 μm or less, good cutting of the workpiece 31 becomes possible.

When the electroformed grindstones 11 and 21 (see FIGS. 1A and 1B) are cut into the workpiece 31, the abrasive grains 41 exposed from the surface of the binder 43 are formed into the workpiece 31. Contact and cut the workpiece 31. Then, when the cutting of the workpiece 31 by the electroformed grindstones 11 and 21 is continued for a certain period of time, the abrasive grains 41 that are exposed due to the wear of the binder 43 fall off and are embedded inside the binder 43. The existing grindstone is newly exposed. This phenomenon is called a self-generated blade, and the self-generated blade maintains the sharpness of the electroformed grindstones 11 and 21.

Further, the binder 43 contains a granular fluororesin 45. For example, as the fluororesin 45, resins such as PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy alkane), FEP (perfluoroethylene propene copolymer), and ETFE (ethylene tetrafluoroethylene copolymer) are dispersed in the binder 43. Will be done.

When the fluororesin 45 is contained in the binder 43, the strength of the region where the fluororesin 45 is present inside the binder 43 is locally reduced. As a result, when the workpiece 31 is cut with the electroformed grindstones 11 and 21, the binder 43 is likely to be worn and the abrasive grains 41 are likely to fall off. As a result, the self-generated blade is promoted, and the sharpness of the electroformed grindstones 11 and 21 is maintained.

However, when the binder 43 is a Ni-plated layer or the like, if the fluororesin 45 is dispersed in the binder 43, the hardness and rigidity of the binder 43 decrease, and the electroformed grindstones 11 and 21 are warped. It will be easier to do. When cutting is performed using such electroformed grindstones 11 and 21, the electroformed grindstones 11 and 21 are chipped or cracked, and the electroformed grindstones 11 and 21 meander when the workpiece 31 is cut. The unintended region of the workpiece 31 may be cut.

Therefore, in the present embodiment, the binder 43 made of an alloy containing nickel and cobalt (Ni—Co alloy) is used. Specifically, a layer made of a Ni—Co alloy (Ni—Co alloy plating layer) formed by electrodeposition is used as the binder 43. The binder 43 made of a Ni—Co alloy has higher strength than the binder made of a Ni plating layer. Therefore, even if the binder 43 made of a Ni—Co alloy contains the fluororesin 45, the decrease in the strength of the binder 43 is suppressed to the extent that the electroformed grindstones 11 and 21 are not damaged or processing defects occur. That is, electroformed grindstones 11 and 21 capable of promoting spontaneous blade generation while suppressing a decrease in strength can be obtained.

There is no limit to the size of the fluororesin 45. For example, the average particle size of the fluororesin 45 is set to 0.1 μm or more and 20 μm or less in order to maintain the promotion effect of the spontaneous blade while suppressing an extreme decrease in the strength of the binder 43 made of a Ni—Co alloy. ..

Next, an example of a method for manufacturing the electroformed grindstones 11 and 21 including the binder 43 made of a Ni—Co alloy will be described. The electroformed grindstones 11 and 21 are manufactured by using, for example, electrolytic plating. In the following, the procedure for manufacturing the electroformed grindstones 11 and 21 using the manufacturing apparatus 40 (see FIGS. 5 and 7) will be described in detail.

FIG. 5 is a partial cross-sectional front view showing a manufacturing apparatus 40 for manufacturing a hub type electroformed grindstone. The manufacturing apparatus 40 includes a plating bath 42 for storing the plating solution 44. As the plating solution 44, an electrolytic solution containing Ni and Co is used. Abrasive particles are dispersed in the plating solution 44. Further, a solution 46 containing a fluororesin is added to the plating solution 44.

A plate-shaped electrode 48 made of Ni and an annular base 51 are immersed in the plating solution 44. Since the base 51 is finally used as the base 13 of the electroformed grindstone 11 (see FIG. 1 (A)), the base 51 is formed in a shape corresponding to the base 13. Further, a mask 53 is formed on the base 51 so as to cover the base 51. The mask 53 has an annular opening corresponding to the shape of the grindstone portion 15 (see FIG. 1A), and a part of the base 51 is exposed inside the opening of the mask 53.

The electrode 48 and the base 51 are connected to the DC power supply 50. Specifically, the electrode 48 is connected to the positive terminal (positive electrode) of the DC power supply 50. Further, the base 51 is connected to the negative terminal (negative electrode) of the DC power supply 50 via the switch 52.

Further, the fan 54 is immersed in the plating solution 44. A rotary drive source 56 such as a motor is connected to the fan 54. When the fan 54 is rotated by the rotation drive source 56, the plating solution 44 is agitated, and the abrasive grains and the fluororesin contained in the plating solution 44 are substantially uniformly dispersed.

When the switch 52 is turned on while stirring the plating solution 44 by the fan 54, the base 51 functions as a cathode and the electrode 48 functions as an anode, and a direct current flows through the plating solution 44. As a result, the Ni—Co alloy plating layer containing the abrasive grains and the fluororesin is electrodeposited on the region of the base 51 that is not covered by the mask 53 and is exposed. Then, after the Ni—Co alloy plating layer having a desired thickness is formed on the base 51, the mask 53 is removed from the base 51.

FIG. 6A is a cross-sectional view showing an annular base 51 on which the Ni—Co alloy plating layer 55 is formed. The base 51 has a front surface 51a, a back surface 51b, and a through hole 51c corresponding to the front surface 13a, the back surface 13b, the through hole 13c, and the convex portion 13d of the electroformed grindstone 11 (see FIG. 1A). , A convex portion 51d is provided. Then, an annular Ni—Co alloy plating layer 55 is formed on the outer peripheral portion of the base 51 on the back surface 51b side.

FIG. 6B is a cross-sectional view showing an annular base 51 having an etched outer peripheral portion. After the Ni—Co alloy plating layer 55 is formed on the base 51, the outer peripheral portion of the base 51 is etched so that the Ni—Co alloy plating layer 55 is placed in the radial direction of the base 51 from the outer peripheral edge of the base 51. Protrude outward. As a result, a hub-type electroformed grindstone in which the annular Ni—Co alloy plating layer 55 formed along the outer peripheral edge of the base 51 functions as a cutting edge can be obtained. This electroformed grindstone corresponds to the electroformed grindstone 11 shown in FIG. 1 (A).

FIG. 7 is a partial cross-sectional front view showing a manufacturing apparatus 40 for manufacturing a washer-type electroformed grindstone. The washer-type electroformed grindstone can also be manufactured by using the manufacturing apparatus 40 in the same manner as the hub-type electroformed grindstone.

When manufacturing a washer-type electroformed grindstone, a disk-shaped base 61 is immersed in the plating solution 44 instead of the base 51 (see FIG. 5). A mask 63 is formed on the base 61 so as to cover the base 61. The mask 63 has an annular opening corresponding to the shape of the grindstone portion 23 (see FIG. 1B), and a part of the base 61 is exposed inside the opening of the mask 63.

When the switch 52 is turned on while stirring the plating solution 44 by the fan 54, the base 61 functions as a cathode and the electrode 48 functions as an anode, and a direct current flows through the plating solution 44. As a result, the Ni—Co alloy plating layer containing the abrasive grains and the fluororesin is electrodeposited on the region of the base 61 that is not covered by the mask 63 and is exposed. FIG. 8A is a cross-sectional view showing a disk-shaped base 61 on which the Ni—Co alloy plating layer 65 is formed.

Then, the annular Ni—Co alloy plating layer 65 is peeled off from the base 61 and separated. As a result, a washer-type electroformed grindstone that functions as a cutting edge can be obtained. FIG. 8B is a cross-sectional view showing a Ni—Co alloy plating layer 65 separated from the disk-shaped base 61. The Ni—Co alloy plating layer 65 thus formed corresponds to the electroformed grindstone 21 shown in FIG. 1 (B).

The electroformed grindstones 11 and 21 shown in FIGS. 1 (A) and 1 (B) are manufactured by the above manufacturing method. The composition ratio of the binder 43 (see FIG. 4) contained in the electroformed grindstones 11 and 21 can be controlled by the concentration of the plating solution 44 (see FIGS. 5 and 7). Further, the content of the fluororesin 45 (see FIG. 4) in the binder 43 can be controlled by the amount of the solution 46 (see FIGS. 5 and 7) containing the fluororesin.

Specifically, the ratio of Ni and Co contained in the plating solution 44 is reflected in the ratio of Ni and Co contained in the binder 43. Further, the ratio of the fluororesin and the metal (Ni and Co) contained in the plating solution 44 is reflected in the content of the fluororesin 45 in the binder 43.

The Co content and the fluororesin 45 content in the binder 43 are adjusted so that the strength of the binder 43 is maintained above a certain level and spontaneous blade generation is likely to occur when the workpiece 31 is cut. Fluorine. Specifically, the Co content in the binder 43 is preferably 5 wt% or more and 30.2 wt% or less. Further, the content of the fluororesin 45 in the binder 43 is preferably 3 vol% or more and less than 40 vol%.

As described above, in the electroformed grindstones 11 and 21 according to the present embodiment, the abrasive grains 41 are fixed by the binder 43 which is made of Ni—Co alloy and contains the fluorine-based resin 45. The strength of the electroformed grindstones 11 and 21 is maintained by the binder 43 made of a Ni—Co alloy having high hardness and high rigidity, and the fluororesin 45 accelerates the detachment of the abrasive grains 41. As a result, it is possible to suppress the decrease in the strength of the electroformed grindstones 11 and 21 and promote the self-generated blade, and it is possible to prevent the electroformed grindstones 11 and 21 from being damaged and processing defects.

Next, the evaluation result of the electroformed grindstone according to the present embodiment will be described. In this evaluation, an electroformed grindstone made of Ni-Co alloy and having abrasive grains fixed by a binder containing a fluororesin is manufactured, and the mechanical properties of the electroformed grindstone and the workpiece are processed by the electroformed grindstone. The processing quality at the time of processing was evaluated.

In this evaluation, a washer-type electroplating grindstone (see FIG. 1 (B)) manufactured by electrolytic plating (see FIG. 7) was used. The dimensions of the electroformed grindstone were set to an outer diameter of 56 mm, an inner diameter of 40 mm, and a thickness of 0.05 mm. As the grindstone, granular diamond (average particle size 8 μm, concentration 45) was used, and as the fluororesin, granular PTFE (average particle size 0.3 μm) was used.

First, nine types of electroformed grindstones having different Co contents in the binder were manufactured. The content of Co in the binder of each electroformed grindstone is 0 wt% (Ni plating layer), 3.1 wt%, 5 wt%, 8.1 wt%, 13.6 wt%, 20.3 wt%, 27.1 wt%, respectively. It was set to 30.2 wt% and 35 wt%. In addition, the content of fluororesin (PTFE) in the binder was unified to 20 vol% for all electroformed grindstones.

The Co content (wt%) described above corresponds to the ratio of the mass of Co in the binder to the mass of the entire binder (the sum of the masses of Ni and Co in the binder). The content of the fluororesin (vol%) corresponds to the total volume of the fluororesin in the binder with respect to the volume of the entire binder. Then, the size, hardness, and rigidity of the warp were measured for each of the nine types of electroformed grindstones.

FIG. 9A is a graph showing the relationship between the Co content and the size of the warp of the electroformed grindstone. The magnitude of the warp of the electroformed grindstone corresponds to the maximum value of the difference in position between the center and the outer peripheral edge of the electroformed grindstone in the thickness direction of the electroformed grindstone. The larger the warp of the electroformed grindstone, the more easily the electroformed grindstone is damaged or meandered when the workpiece is cut with the electroformed grindstone.

As shown in FIG. 9A, when a Co-containing binder (Ni—Co alloy plating layer) is used, an electroformed grindstone is used as compared with the case where a Co-free binder (Ni plating layer) is used. Warpage has been reduced. In particular, when the Co content is 5 wt% or more and 30.2 wt% or less, the warp size of the electroformed grindstone is reduced to 1/3 or less of that when the Ni plating layer is used, and the electroformed grindstone It was confirmed that it is extremely effective in suppressing warpage.

FIG. 9B is a graph showing the relationship between the Co content and the hardness (Vickers hardness) of the electroformed grindstone. Further, FIG. 9C is a graph showing the relationship between the Co content and the rigidity of the electroformed grindstone. As shown in FIGS. 9B and 9C, when the Ni—Co alloy plating layer was used, the hardness and rigidity of the electroformed grindstone were improved as compared with the case where the Ni plating layer was used. In particular, when the Co content is 8.1 wt% or more and 30.2 wt% or less, the increase in hardness is remarkable, and it has been confirmed that it is extremely effective in improving the strength of the electroformed grindstone.

Next, eight types of electroformed grindstones having different contents of the fluororesin (PTFE) in the binder were manufactured. The content of the fluororesin in the binder of each electroformed grindstone was 0 vol% (without fluororesin), 5 vol%, 10 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, and 40 vol%, respectively. The Co content in the binder was unified to 20 wt% for all electroformed grindstones. Then, the rigidity of each of the eight types of electroformed grindstones was measured.

FIG. 10A is a graph showing the relationship between the content of the fluororesin and the rigidity (Vickers hardness) of the electroformed grindstone. As shown in FIG. 10A, when a Ni—Co alloy plating layer is used as the binder, the rigidity of the electroformed grindstone hardly changes even if the binder contains a fluororesin, and the electroformed grindstone has the same rigidity. It was confirmed that the strength does not easily decrease due to the mixing of fluororesin. However, when the content of the fluororesin reached 40 vol%, the electroformed grindstone became brittle and damaged. Therefore, the content of the fluororesin is preferably less than 40 vol%, more preferably 35 vol% or less.

Next, the workpiece was actually cut using seven types of electroformed grindstones having different contents of the fluororesin (PTFE) in the binder. The content of the fluororesin in the binder of each electroformed grindstone was 0 vol% (without fluororesin), 3 vol%, 10 vol%, 20 vol%, 25 vol%, 30 vol%, and 35 vol%, respectively. The Co content in the binder was unified to 20 wt% for all electroformed grindstones. Then, after cutting the workpiece with each electroformed grindstone, the machining quality was evaluated by measuring the size of the chipping (chipping) generated in the workpiece.

As the work piece, borosilicate glass having a length of 100 mm, a width of 100 mm, and a thickness of 0.5 mm was used. A cutting device (see FIG. 2) was used for cutting the workpiece. Then, the workpiece held by the chuck table was cut with an electroformed grindstone, and the workpiece was divided into a plurality of chips.

Specifically, first, the electroformed grindstone was placed on the outside of the workpiece. Further, the height of the electroformed grindstone was adjusted so that the lower end of the electroformed grindstone was positioned below the lower surface of the workpiece. Then, while rotating the electric casting grindstone (rotation speed: 15000 / min), the chuck table is moved along a direction substantially parallel to the length direction of the workpiece (machining feed rate: 10 mm / s) to be machined. The object was cut along the length direction. Then, while moving the electroformed grindstone in the width direction of the workpiece at intervals of 5 mm, the cutting of the workpiece was repeated in the same procedure.

Next, the chuck table was rotated 90 ° in the horizontal direction, and the workpiece was cut a plurality of times along the width direction under the same conditions. As a result, the workpiece was divided into a plurality of rectangular parallelepiped chips (length 5 mm, width 5 mm, thickness 0.5 mm).

Then, the lower surface side of the divided workpiece (plurality of chips) was observed, and the longest chipping (maximum chipping) among the chippings extending from the cut end on the lower surface side of the workpiece was identified. Then, the maximum chipping length was measured and recorded as the maximum chipping size. The above work was performed on each of the seven workpieces cut by the seven types of electroformed grindstones.

FIG. 10B is a graph showing the relationship between the content of the fluororesin and the maximum chipping size. As shown in FIG. 10B, when the content of the fluororesin was 3 vol% or more, the maximum chipping size was significantly reduced. In particular, when the content of the fluororesin was 20 vol% or more, the maximum chipping size was significantly reduced (8 μm or less), and it was confirmed that the processing quality was extremely effectively improved. It is presumed that the reduction in the maximum chipping size as described above is due to the fact that the self-generated blade is promoted by the fluororesin and the sharpness of the electroformed grindstone is maintained.

From the above evaluation results, it was confirmed that the electroformed grindstone according to the present embodiment has high strength and characteristics that spontaneous blades are likely to occur.

The structure, method, and the like according to the present embodiment can be appropriately modified and implemented as long as they do not deviate from the scope of the object of the present invention.

11 Electroformed grindstone 13 Base 13a Front surface 13b Back surface 13c Through hole 13d Convex part 15 Grindstone part 21 Electroformed grindstone 23 Grindstone part 23a Front surface 23b Back surface 23c Through hole 31 Work piece 41 Abrasive grain 43 Bonding material
45 Fluorine-based resin 51 Base 51a Front 51b Back 51c Through hole 51d Convex 53 Mask 55 Ni-Co alloy plating layer 61 Base 63 Mask 65 Ni-Co alloy plating layer 2 Cutting equipment 4 Base 6 Cover 6a Front 8 Cutting Unit 10 Housing 12 Spindle 14 Mount 16 Flange 16a Surface 16b Convex 18 Support shaft (boss)
18a Thread 20 Fixing nut 20a Opening 22 Chuck table (holding table)
22a Holding surface 24 Cassette elevator 26 Cassette 28 Display unit (display unit, display device)
30 Control unit (control unit, control device)
40 Manufacturing equipment 42 Plating bathtub 44 Plating solution 46 Solution 48 Electrode 50 DC power supply 52 Switch 54 Fan 56 Rotational drive source

Claims (6)

A grindstone portion including an abrasive grain and a binder for fixing the abrasive grain is provided.
The binder is an electroformed grindstone made of a Ni—Co alloy and containing a fluororesin. The electroformed grindstone according to claim 1, wherein the content of Co in the binder is 5 wt% or more and 30.2 wt% or less. The electroformed grindstone according to claim 1 or 2, wherein the content of the fluororesin in the binder is 3 vol% or more and less than 40 vol%. The average particle size of the abrasive grains is 1 μm or more and 80 μm or less.
The electroformed grindstone according to any one of claims 1 to 3, wherein the fluororesin has an average particle size of 0.1 μm or more and 20 μm or less. The electroformed grindstone according to any one of claims 1 to 4, further comprising an annular base and an annular grindstone portion formed along the outer peripheral edge of the base. The electroformed grindstone according to any one of claims 1 to 4, wherein the electroformed grindstone is composed of an annular grindstone portion.

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