Chip manufacturing method

Abstract

To divide a workpiece into a plurality of chips and to polish the end surfaces of the chips by using a cutting device.SOLUTION: This chip manufacturing method comprises: a first holding step of holding a workpiece on a first holding table; a division step of cutting and dividing the workpiece into a plurality of chips by moving a first cutting blade rotated about a first spindle and the first holding table relative to each other in a machining feed direction orthogonal to the longitudinal direction to the first spindle; a second holding step of holding at least one of the chips on a second holding table so as to expose upward the end surface exposed through cutting; and a polishing step of polishing the end surface at the lower end by moving a second cutting blade and the second holding table relative to each other in an indexing feed direction which is the longitudinal direction of the second spindle in state where the lower end of the second cutting blade rotated about the second spindle cuts the end surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a chip, which comprises polishing the end faces of a chip separated from a workpiece by cutting to produce a chip having a mirror-finished end face. [Background technology]

[0002] Optical waveguides that function as optical circuits are used for switching optical transmission paths, multiplexing optical waves, demultiplexing optical waves, etc. Optical waveguides generally have a core that serves as an optical transmission path, and a cladding for confining the light in the core.

[0003] An optical waveguide may have the form of a rectangular plate-shaped device chip (hereinafter, simply referred to as a chip) also called a planar lightwave circuit (PLC). A chip that functions as an optical waveguide has, for example, a support substrate, a lower clad on the support substrate, an upper clad on the lower clad, and a core sandwiched between the lower clad and the upper clad.

[0004] The chip includes a front surface, a back surface, and four side surfaces that connect the outer peripheries of the front and back surfaces, each of which is substantially flat. Of the four side surfaces, two side surfaces that are substantially parallel to each other function as a light input surface, and the other side surface functions as a light output surface.

[0005] In order to allow light to pass through the chip efficiently, the entrance and exit surfaces need to be finished to a mirror-like state with few irregularities. However, when a single workpiece is cut into multiple chips, cutting marks remain on the end faces of the chips (especially the end faces of the core) that correspond to the entrance and exit surfaces, and the cutting marks impede the entrance and exit of light.

[0006] In order to reduce cutting marks and make the entrance and exit surfaces mirror-finished, it is possible, for example, to fix the chip in a state where the end face of the chip is exposed using some kind of jig or the like, and then polish the end face of the chip using a polishing device having a spindle with a disc-shaped polishing pad attached to the tip.

[0007] In addition, in a grinding process using a grinding device, a grinding technique is known that reduces grinding marks on one of the front and back surfaces of a chip (see, for example, Patent Document 1). However, using a polishing device or a grinding device in addition to a cutting device increases the cost required for manufacturing the chip. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2002-75941 A Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of these problems, and aims to divide a workpiece into multiple chips and polish the end faces of the chips by using a cutting device without using either a polishing device or a grinding device. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided a method for manufacturing chips having mirror-finished end faces by polishing end faces of chips separated from a workpiece by cutting, the method including: a first holding step of holding the workpiece on a first holding table; a dividing step of cutting the workpiece and dividing it into a plurality of chips by relatively moving a first cutting blade that rotates around a first spindle as a rotation axis and the first holding table after the first holding step along a processing feed direction perpendicular to the longitudinal direction of the first spindle; Thereafter, a second holding step is performed of holding at least one of the plurality of chips on a second holding table so that the end face exposed by cutting is exposed upward, and after the second holding step, a polishing step is performed of polishing the end face with the lower end of a second cutting blade which rotates around a second spindle as a rotation axis, by relatively moving the second cutting blade and the second holding table along an indexing feed direction which is the longitudinal direction of the second spindle.

[0011] Preferably, the chip manufacturing method further includes a flat dressing step, after the dividing step and before the polishing step, of dressing the first cutting blade by relatively moving the first cutting blade and the first holding table along the longitudinal direction of the first spindle with the lower end of the first cutting blade rotating around the rotation axis positioned at a position lower than the upper surface of a dress board held by the first holding table, and the second cutting blade is identical to the first cutting blade.

[0012] Also, preferably, the chip manufacturing method further includes a flat dressing process, after the dividing process and before the polishing process, in which the lower end of the second cutting blade rotating around the rotation axis is positioned at a position lower than the upper surface of the dressing board held by the second holding table, and the second cutting blade and the second holding table are moved relatively along the index feed direction to dress the second cutting blade, and the second cutting blade is different from the first cutting blade.

[0013] Also, preferably, in the polishing step, two end faces located opposite each other among the four end faces of the at least one chip are polished sequentially.

[0014] Also, preferably, each of the at least one chip includes an optical waveguide having a core through which light propagates and a cladding for confining the light in the core, the core being exposed at the two end faces polished in the polishing process, one of the two end faces corresponding to the light entrance face into the optical waveguide and the other of the two end faces corresponding to the light exit face from the optical waveguide.

[0015] Also, preferably, in the polishing step, the end surface is polished with the second cutting blade and the at least one tip positioned so as to intersect with each other when the second holding table is viewed in a plane.

[0016] Also, preferably, in the second holding step, the at least one chip fixed to a substrate or a dicing tape with wax is held by the second holding table. Effect of the Invention

[0017] In the method for manufacturing a chip according to one aspect of the present invention, a cutting device is used to both divide a workpiece into a plurality of chips and polish the end faces of the chips. Therefore, the cost required for manufacturing chips with mirror-finished end faces can be reduced compared to the case where a polishing device or a grinding device is used in addition to a cutting device. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a flow diagram of a method for manufacturing a chip according to the first embodiment. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4]FIG. 4(A) is a partially sectional side view showing how a workpiece unit is placed on a holding surface, and FIG. 4(B) is a diagram showing a first holding step. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 7(A) is a plan view of the chip, FIG. 7(B) is a front view of the chip, and FIG. 7(C) is a right side view of the chip. [Figure 8] FIG. 8(A) is a partial cross-sectional side view showing how the chip is fixed to the support substrate, and FIG. 8(B) is a diagram showing the second holding step. [Figure 9] FIG. 9(A) is a partially sectional side view showing the grinding step, and FIG. 9(B) is a plan view showing the positional relationship between another cutting blade and tip in the grinding step. [Figure 10] FIG. [Figure 11] FIG. 11(A) is a flow diagram of a method for manufacturing a chip in the second embodiment, and FIG. 11(B) is a flow diagram of a modified example of the second embodiment. [Figure 12] FIG. 4 is a partial cross-sectional side view showing a flat dressing process. [Figure 13] FIG. 11 is a perspective view showing a flat dressing process. [Figure 14] FIG. 14(A) is a schematic diagram of a cross section of a cutting blade before a flat-dressing process, and FIG. 14(B) is a schematic diagram of a cross section of a cutting blade after a flat-dressing process. [Figure 15] FIG. 2 is a partial cross-sectional side view showing a cutting device having a dual spindle structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (First embodiment) An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a flow diagram of a method for manufacturing a chip 11 (see Fig. 7) according to a first embodiment. In the first embodiment, a first holding step S10, a dividing step S20, a second holding step S30, and a polishing step S40 are performed in this order using a cutting device 2 (see Fig. 2).

[0020] First, a description will be given of the cutting device 2. Fig. 2 is a perspective view of the cutting device 2. Note that the X-axis direction (processing feed direction), Y-axis direction (indexing feed direction), and Z-axis direction (height direction, vertical direction) shown in Fig. 2 are mutually orthogonal.

[0021] The cutting device 2 includes a base 4 that supports or houses each of the components. A rectangular opening 4a is formed in the base 4, with its longitudinal portion disposed along the X-axis direction. A rectangular table cover 6 is provided within the opening 4a.

[0022] Bellows-shaped cover members 8 that are extendable and contractible along the X-axis direction are provided on both sides of the table cover 6 in the X-axis direction. A disk-shaped chuck table (first holding table, also serving as a second holding table) 10 is provided on the table cover 6.

[0023] The chuck table 10 has a disk-shaped frame made of metal. The frame has a disk-shaped recess that opens to the upper surface. A disk-shaped porous plate made of porous ceramics is fixed in the recess of the frame.

[0024] The upper surfaces of the frame and the porous plate are substantially flush with each other, forming a holding surface 10a that is substantially parallel to the XY plane. A suction source (not shown) such as a vacuum pump is connected to the frame. When negative pressure generated by the suction source is transmitted to the porous plate, negative pressure is generated on the upper surface of the porous plate.

[0025] Using this negative pressure, the workpiece 21 is sucked and held by the holding surface 10a. A plurality of clamp units 10b (four in this embodiment) are arranged at approximately equal intervals along the outer periphery of the frame.

[0026] The workpiece 21 of this embodiment includes a rectangular support substrate 13 and an optical waveguide 15 formed on one surface of the support substrate 13 (see FIG. 7(B)). The optical waveguide 15 includes the above-mentioned core 17, lower cladding 19a, and upper cladding 19b (see FIG. 7(B)).

[0027] For example, the support substrate 13 is made of single crystal silicon, and the optical waveguide 15 is mainly made of silicon oxide. Also, for example, the support substrate 13 is made of a non-crystalline resin, and the optical waveguide 15 is mainly made of a crystalline resin.

[0028] A plurality of mutually intersecting planned division lines 21c are set on the surface 21a of the workpiece 21 (see FIG. 3). FIG. 3 is a plan view of the workpiece 21. The planned division lines 21c may be explicit lines, or may be virtual lines that can be identified based on marks (not shown) formed on the surface 21a.

[0029] An optical waveguide 15 is formed in each rectangular region 21d defined by the plurality of planned division lines 21c. By cutting the workpiece 21 along each planned division line 21c by the cutting device 2, the workpiece 21 is divided into a plurality of rectangular chips 11 (i.e., optical device chips), each of which has an optical waveguide 15.

[0030] 2, a dicing tape 23 having an outer diameter longer than the diagonal length of the front surface 21a of the workpiece 21 is attached to the back surface 21b of the workpiece 21. A metal annular frame 25 is disposed on the outer periphery of the workpiece 21 at a distance from the workpiece 21, and the outer periphery of the dicing tape 23 is attached to one surface of the annular frame 25.

[0031] The dicing tape 23 has a laminated structure of, for example, a resin base layer and a resin adhesive layer provided on one surface of the base layer. In the workpiece unit 27 in which the workpiece 21 and the annular frame 25 are integrated via the dicing tape 23, the workpiece 21 is supported by the annular frame 25 via the dicing tape 23.

[0032] After the workpiece unit 27 is placed on the chuck table 10, negative pressure is transmitted to the holding surface 10a, whereby the workpiece 21 is suction-held on the holding surface 10a via the dicing tape 23, and four points of the annular frame 25 are clamped by the clamp unit 10b.

[0033] A rotation mechanism (not shown) such as a motor is provided below the chuck table 10, and the chuck table 10 can rotate around a predetermined rotation axis arranged substantially parallel to the Z-axis direction. The chuck table 10 and the rotation mechanism are supported by an X-axis direction moving plate (not shown).

[0034] The X-axis direction moving plate can be moved along the X-axis direction by an X-axis direction moving mechanism (not shown). The X-axis direction moving mechanism has a pair of guide rails arranged substantially parallel to the X-axis direction. The X-axis direction moving plate is slidably attached to the pair of guide rails.

[0035] A nut portion is provided on the lower surface of the X-axis direction moving plate, and a screw shaft arranged substantially parallel to the X-axis direction is rotatably coupled to the nut portion via a plurality of balls. An X-axis direction drive source such as a stepping motor is connected to one end of the screw shaft.

[0036] When the X-axis direction drive source is operated, the X-axis direction moving plate, the rotation mechanism, and the chuck table 10 move integrally along the X-axis direction. A cantilever-shaped support structure 12 is provided at a position adjacent to the opening 4a in the Y-axis direction.

[0037] A Y-axis / Z-axis movement mechanism 14 is provided on the upper front surface of the support structure 12. The Y-axis / Z-axis movement mechanism 14 has a pair of Y-axis guide rails 16 arranged substantially parallel to the Y-axis direction. A Y-axis movement plate 18 is slidably attached to the Y-axis guide rails 16.

[0038] A nut portion (not shown) is provided on the back surface of the Y-axis direction moving plate 18, and a screw shaft 20 arranged substantially parallel to the Y-axis direction is rotatably connected to this nut portion via a plurality of balls. One end portion of the screw shaft 20 is connected to a Y-axis direction drive source such as a stepping motor (not shown).

[0039] When the screw shaft 20 is rotated by a Y-axis direction drive source, the Y-axis direction moving plate 18 moves along the Y-axis direction. A pair of Z-axis direction guide rails 22 arranged approximately parallel to the Z-axis direction are provided on the surface of the Y-axis direction moving plate 18.

[0040] A Z-axis direction moving plate 24 is slidably attached to the pair of Z-axis direction guide rails 22. A nut portion (not shown) is provided on the rear surface of the Z-axis direction moving plate 24, and a screw shaft 26 arranged substantially parallel to the Z-axis direction is rotatably connected to this nut portion via a plurality of balls.

[0041] A Z-axis direction drive source 28 such as a stepping motor (not shown) is connected to the upper end of the screw shaft 26. When the screw shaft 26 is rotated by the Z-axis direction drive source 28, the Z-axis direction moving plate 24 moves along the Z-axis direction.

[0042] A cutting unit 30 is fixed to the lower end of the Z-axis direction moving plate 24. The cutting unit 30 has a spindle housing 32 whose longitudinal portion is disposed along the Y-axis direction. A cylindrical spindle (first spindle, also serving as a second spindle) 34 (see FIG. 5) is partially rotatably housed within the spindle housing 32.

[0043] The longitudinal direction of the spindle 34 is also arranged along the Y-axis direction, similar to the spindle housing 32. As shown in Fig. 5, a cutting blade (first cutting blade) 36 having an annular cutting edge 36a is attached to the tip of the spindle 34.

[0044] The cutting blade 36a has abrasive grains (for example, diamond grains) and a bonding material (for example, metal bond) for fixing the abrasive grains. The grain size of the abrasive grains in the cutting blade 36a is, for example, #1200.

[0045] The particle size shall conform to JIS R 6001-2:2017 (Particle size of abrasives for grinding wheels - Part 2: Fine powder) of the Japanese Industrial Standards (JIS), or be determined by each manufacturer in accordance therewith.

[0046] The cutting blade 36 is detachable from the spindle 34. For example, after the cutting blade 36 is used in the dividing step S20, another cutting blade (second cutting blade) 46 (see FIG. 9(A)) is attached to the spindle 34 in the grinding step S40.

[0047] 6, a blade cover 38 is provided at the tip of the spindle housing 32 so as to cover the upper region of the cutting blade 36. A pair of nozzle units 40 are attached to the blade cover 38 so as to sandwich the cutting blade 36a in the thickness direction of the cutting blade 36a (i.e., the Y-axis direction).

[0048] A plurality of cooler nozzles 40a are provided on the inner surface of each nozzle unit 40. Each cooler nozzle 40a sprays cutting water such as pure water toward the lower end of the cutting blade 36a during cutting.

[0049] Further, a nozzle unit 42 is attached to the blade cover 38 so as to face the outer peripheral side surface of the cutting blade 36a in the X-axis direction. A shower nozzle 42a is provided on the inner surface of the nozzle unit 42. The shower nozzle 42a sprays cutting water toward the outer peripheral side surface of the cutting blade 36a during cutting.

[0050] Returning to Fig. 2, a microscope camera unit 44 is fixed to the lower end of the Z-axis direction moving plate 24. The microscope camera unit 44 includes a lens, a predetermined optical system, a solid-state image sensor, etc. (none of which are shown). The image obtained by the microscope camera unit 44 is used, for example, to align the workpiece 21 with the cutting blades 36, 46.

[0051] Next, each step shown in Fig. 1 will be described with reference to Fig. 4(A) to Fig. 10. Fig. 4(A) is a partially sectional side view showing how workpiece unit 27 is placed on holding surface 10a, and Fig. 4(B) is a diagram showing a first holding step S10.

[0052] After the workpiece unit 27 is placed on the holding surface 10a, negative pressure is transmitted to the holding surface 10a, and the clamp unit 10b clamps the annular frame 25. In this manner, the workpiece 21 is suction-held on the holding surface 10a.

[0053] After the first holding step S10, a dividing step S20 is performed. Fig. 5 is a partially cross-sectional side view showing the dividing step S20, and Fig. 6 is a perspective view showing the dividing step S20. For convenience, the chuck table 10 is omitted in Fig. 6.

[0054] In the dividing step S20, first, the orientation of the chuck table 10 is adjusted using the microscope camera unit 44 so that the dividing line 21c of the workpiece 21 is approximately parallel to the X-axis direction.

[0055] Next, the cutting blade 36 is rotated around the spindle 34 as a rotation axis, and the position of the lower end 36b of the cutting blade 36 is adjusted by the Y-axis / Z-axis direction moving mechanism 14 in a region outside the workpiece 21 in the XY plane.

[0056] Specifically, the Z-axis position of the lower end 36b of the cutting blade 36 is positioned between the back surface 21b of the workpiece 21 and the holding surface 10a, and the Y-axis position of the cutting blade 36 is positioned on an extension line of the planned division line 21c.

[0057] Then, while supplying cutting water (not shown) at a predetermined flow rate from each of the cooler nozzles 40a and the shower nozzle 42a, the cutting blade 36 and the chuck table 10 are moved relatively at a predetermined speed along the X-axis direction (i.e., fed for processing). In this embodiment, the chuck table 10 is fed for processing while the position of the cutting unit 30 is fixed.

[0058] As a result, the workpiece 21 is cut along one of the planned dividing lines 21c. Next, in an area outside the workpiece 21 in the XY plane, the cutting blade 36 and the chuck table 10 are moved along the Y-axis direction by a predetermined index amount.

[0059] Similarly, the cutting blade 36 and the chuck table 10 are moved relatively at a predetermined speed along the X-axis direction to cut the workpiece 21 along the other intended dividing line 21c.

[0060] After cutting the workpiece 21 along all the planned dividing lines 21c along the first direction, the chuck table 10 is rotated approximately 90 degrees, and the workpiece 21 is similarly cut by cutting along all the planned dividing lines 21c along the second direction perpendicular to the first direction.

[0061] In this manner, the workpiece 21 is divided into a plurality of chips 11 by cutting alone. An example of processing conditions in the dividing step S20 is shown below. The workpiece 21 is, for example, 0.9 mm thick, 100 mm long, and 100 mm wide.

[0062] Spindle speed: 30,000 rpm Cooler nozzle cutting water flow rate: 1.0L / min (total flow rate of each cooler nozzle) Shower nozzle cutting water flow rate: 1.0L / min Machining feed speed: 5mm / s Index amount: 20mm

[0063] 7A is a plan view of the chip 11. The size of the chip 11 in the plan view is, for example, 20 mm in length and 20 mm in width. The chip 11 has two end faces 11c1 and two end faces 11c2 that connect the outer peripheries of the front surface 11a and back surface 11b.

[0064] The pair of end faces 11c1 are disposed substantially parallel to each other, and the pair of end faces 11c2 are also disposed substantially parallel to each other. Each of the end faces 11c1 and the end face 11c2 is a surface exposed by cutting, not a surface exposed by cleavage.

[0065] Therefore, scratches (not shown) caused by cutting are formed on almost the entirety of each of the end faces 11c1 and 11c2. In particular, the cutting marks formed on the optical waveguide 15 cause an obstruction to the incidence and emission of light into and from the chip 11.

[0066] 7B is a front view of the chip 11, showing the end surface 11c1. Each of the chips 11 has substantially the same structure. As shown in FIG. 7B, each chip 11 has a resin support substrate 13 and an optical waveguide 15 formed on one surface of the support substrate 13.

[0067] The optical waveguide 15 has a core 17 through which light propagates, and a lower clad 19a and an upper clad 19b (i.e., clads) for confining the light in the core 17. The core 17 is sandwiched between the lower clad 19a and the upper clad 19b in the thickness direction of the chip 11 proceeding from the front surface 11a to the back surface 11b.

[0068] As shown in Fig. 7(B), the core 17 is exposed at two opposing end faces 11c1, one of which corresponds to an incident surface of light into the optical waveguide 15, and the other of which corresponds to an exit surface of light from the optical waveguide 15. Fig. 7(C) is a right side view of the chip 11, showing the end face 11c2.

[0069] In this embodiment, after the dividing step S20, a second holding step S30 (see FIG. 8(B)) is performed, and then in the polishing step S40 (see FIG. 9(A), FIG. 9(B), and FIG. 10), the two end faces 11c1 which become the light entrance and exit surfaces are polished sequentially.

[0070] Particularly in this embodiment, after the dividing step S20 and before the second holding step S30, the cutting blade is removed from the spindle and a different cutting blade (second cutting blade) 46 is attached to the spindle .

[0071] The cutting blade 46 has a cutting edge 46a having substantially the same shape as the cutting edge 46a. The cutting edge 46a has abrasive grains (for example, diamond abrasive grains) and a bonding material (for example, a vitrified bond) for fixing the abrasive grains.

[0072] However, the grain size of the abrasive grains in the cutting blade 46a is, for example, #2000, and the average grain size of the abrasive grains in the cutting blade 46a is smaller than the average grain size of the abrasive grains in the cutting blade 36a. In this way, the cutting blade 46 differs from the cutting blade 36 in terms of the grain size of the abrasive grains and the binder.

[0073] FIG. 8(A) is a partial cross-sectional side view showing how at least one chip 11 is fixed to a substrate 31 with wax 31a after the dividing step S20 and replacement of the cutting blade, and before the second holding step S30.

[0074] 8(A), one chip 11 is fixed to the substrate 31, but two or more chips 11 may be fixed to the substrate 31. Each chip 11 is fixed to one surface 31b of the substrate 31 such that one end surface 11c1 is exposed upward in a state substantially parallel to the XY plane (e.g., a horizontal plane).

[0075] The wax 31a is a solid wax, and may be, for example, the ADFIX Series sold by Nikka Seiko Co., Ltd. The melting point of the solid wax is a predetermined temperature exceeding 100° C. (for example, 130° C.).

[0076] The substrate 31 is a flat plate material, for example, a single crystal silicon substrate, but may be a plate material formed of other hard materials such as a heat-resistant resin (e.g., epoxy resin) that does not melt even at a predetermined temperature exceeding 100°C.

[0077] A circular dicing tape 33 is attached to the other surface 31c of the substrate 31. The substrate 31 is supported by an annular frame 35 via the dicing tape 33. The dicing tape 33 corresponds to the above-mentioned dicing tape 23, and the annular frame 35 corresponds to the above-mentioned annular frame 25.

[0078] By fixing the chip 11 upright on the substrate 31 using the wax 31a, one or more chips 11 can be fixed to the chuck table 10 of the cutting device 2 without using a dedicated jig for fixing the chip 11.

[0079] The chip 11, wax 31a, substrate 31, dicing tape 33 and annular frame 35 constitute a chip unit 37. Fig. 8(B) is a diagram showing a second holding step S30 in which the chip unit 37 is held by the chuck table 10 under suction.

[0080] After the chip unit 37 is placed on the holding surface 10a, a negative pressure is transmitted to the holding surface 10a, and the clamp unit 10b clamps the annular frame 35. In this manner, the chip 11 is suction-held on the holding surface 10a so that one end face 11c1 is exposed upward and disposed approximately parallel to the XY plane.

[0081] After the second holding step S30, a grinding step S40 is performed using the cutting device 2. Fig. 9(A) is a partially cross-sectional side view showing the grinding step S40, and Fig. 9(B) is a plan view showing the positional relationship between the cutting blade 46 and the tip 11 in the grinding step S40. Fig. 10 is a perspective view showing the grinding step S40. For convenience, the chuck table 10 is omitted in Fig. 10.

[0082] In the polishing step S40, first, the orientation of the chuck table 10 is adjusted using the microscope camera unit 44 so that the longitudinal direction of the end face 11c1 exposed upward is approximately parallel to the Y-axis direction. Therefore, as shown in FIG. 9B, when the chuck table 10 is viewed in plan, the cutting blade 46 and the tip 11 are arranged to intersect with each other.

[0083] In this embodiment, the angle θ between the cutting blade 46 and one side constituting the end face 11c1 of the tip 11 is set to approximately 90 degrees. This arrangement reduces the force applied to the tip 11 in the direction along the thickness direction of the tip 11 during grinding, compared to when the cutting blade 46 and the tip 11 are arranged approximately parallel to each other in a plan view, thereby reducing the breakage, cracking, chipping, etc. of the tip 11 during grinding.

[0084] Next, the cutting blade 46 is rotated around the spindle 34 as a rotation axis, and the position of the lower end 46b of the cutting blade 46 in the Y-axis and Z-axis directions is adjusted by the Y-axis / Z-axis moving mechanism 14, and the position of the tip 11 in the X-axis direction is adjusted by the X-axis moving mechanism.

[0085] Specifically, the lower end 46b of the cutting blade 46 is positioned on an extension of a straight line connecting the multiple cores 17 exposed on the end face 11c1 (see Figure 9(B)), and this lower end 46b is positioned below the end face 11c1 by a small depth Δ (e.g., 1 μm) in the Z-axis direction (see Figure 9(A)).

[0086] In this embodiment, when polishing begins, the cutting blade 46 is positioned on the outside of the end face 11c1 in the Y-axis direction as described above, but when polishing begins, the cutting blade 46 may also be cut into the chip 11 to a minute depth Δ at one end of the end face 11c1 in the Y-axis direction.

[0087] After adjusting the relative positions of the tip 11 and the cutting blade 46, the cutting blade 46 and the chuck table 10 are moved relatively at a predetermined speed along the Y-axis direction while supplying cutting water (not shown) at a predetermined flow rate from each cooler nozzle 40a and shower nozzle 42a.

[0088] That is, in a state where the lower end 46b of the cutting blade 46 is cut into the end face 11c1 by a minute depth Δ, the cutting blade 46 and the chuck table 10 are indexed and fed. As a result, the area of ​​the end face 11c1 where the lower end 46b of the cutting blade 46 has moved is polished by the lower end 46b to a mirror finish (first polishing).

[0089] That is, by processing the tip 11 with the cutting blade 46 so as to gently stroke the end face 11c1 with the lower end 46b of the cutting blade 46, the unevenness of the end face 11c1 is smoothed and flattened. At the end of the first polishing, the cutting blade 46 may be removed outside the other end of the end face 11c1 in the Y-axis direction, or may be positioned at the other end of the end face 11c1 in the Y-axis direction.

[0090] In this embodiment, after the first polishing is completed, the position of the chuck table 10 in the X-axis direction is fixed, the lower end 46b is positioned further downward by a small depth Δ than in the first polishing, and the cutting blade 46 is moved in the opposite direction along the Y-axis direction to that in the first polishing (second polishing).

[0091] In this embodiment, during grinding, the cutting blade 46 is moved at a predetermined speed in both directions along the Y-axis direction, but during grinding, the cutting blade 46 may also be moved at a predetermined speed only in a predetermined direction along the Y-axis direction.

[0092] After the second polishing is completed, the lower end 46b is positioned further downward by a minute depth Δ from the second polishing, and the cutting blade 46 is moved in the same direction along the Y-axis as the first polishing, thereby performing a third polishing.

[0093] In the grinding step S40 of this embodiment, the cutting blade 46 is moved relative to the end surface 11c1 in this manner multiple times (for example, 10 times in total), but the grinding step S40 may be ended after the first grinding. An example of processing conditions in the grinding step S40 is shown below.

[0094] Spindle speed: 20,000 rpm Cooler nozzle cutting water flow rate: 1.0L / min (total flow rate of each cooler nozzle) Shower nozzle cutting water flow rate: 1.0L / min Indexing feed rate: 0.5mm / s

[0095] In addition, in the polishing process S40, while keeping the position of the lower end 46b in the Z-axis direction relative to the end face 11c1 fixed, after the cutting blade 46 has completed moving along the Y-axis direction, the cutting blade 46 is processed and fed along the X-axis direction, and then the cutting blade 46 is moved along the Y-axis direction, so that polishing can be performed on almost the entire end face 11c1.

[0096] In the polishing step S40 of this embodiment, after polishing one end face 11c1, the wax 31a is melted and the chip 11 is turned upside down to expose the other end face 11c1 upward. Then, the polishing step S40 is similarly performed on the other end face 11c1.

[0097] In this embodiment, the cutting device 2 can be used to both divide the workpiece 21 into a plurality of chips 11 and polish the end faces 11c1 of the chips 11. Therefore, the cost required to manufacture the chips 11 having the mirror-finished end faces 11c1 can be reduced compared to the case where a polishing device or a grinding device is used in addition to the cutting device 2.

[0098] Second Embodiment Next, a second embodiment will be described. In the method for manufacturing the tip 11 in the second embodiment, either the cutting blade 36 or the cutting blade 46 (that is, the same cutting blade) is used throughout.

[0099] Therefore, the cutting blade 36 or cutting blade 46 to be used is flat-dressed after the dividing step S20 and before the second holding step S30. For convenience of explanation, an example in which the cutting blade 36 is used consistently will be described below, but the cutting blade 46 may be used consistently. Therefore, the cutting blade 36 may be read as the cutting blade 46.

[0100] Fig. 11(A) is a flow diagram of a method for manufacturing chip 11 in the second embodiment, in which a flat dressing step S25 is performed between the dividing step S20 and the second holding step S30. Fig. 11(B) is a flow diagram of a method for manufacturing chip 11 in a modified example of the second embodiment, in which a flat dressing step S35 is performed between the second holding step S30 and the polishing step S40.

[0101] Fig. 12 is a partially sectional side view showing the flat dressing steps S25 and S35, and Fig. 13 is a perspective view showing the flat dressing steps S25 and S35. In the flat dressing steps S25 and S35, a dress board unit 47 in which a rectangular plate-shaped dress board 41, a dicing tape 43, and an annular frame 45 are integrated is used.

[0102] The dress board 41 has a laminated structure including a dress portion 41a formed using a mixed material in which abrasive grains such as white alundum (WA) or green carbon (GC) are mixed with a bonding material such as a vitrified bond or a resin bond, and a resin substrate 41b to which one side of the dress portion 41a is fixed.

[0103] However, the average grain size of the abrasive grains constituting the dressing portion 41a is smaller than the average grain size of the cutting blade 36 to which the flat dressing is applied. The dicing tape 43 corresponds to the above-mentioned dicing tape 23, and the annular frame 45 corresponds to the above-mentioned annular frame 25.

[0104] 12, in the flat dressing steps S25 and S35, first, the dress board unit 47 is suction-held on the chuck table 10 so that the dress portion 41a is exposed upward. As a result, the dress board 41 is suction-held on the holding surface 10a via the dicing tape 43.

[0105] Next, using the microscope camera unit 44, the orientation of the chuck table 10 is adjusted so that one side of the dress board 41 is approximately parallel to the X-axis direction and the other side perpendicular to the one side is approximately parallel to the Y-axis direction.

[0106] Then, the lower end 36b of the cutting blade 36 rotating around the spindle 34 is positioned at a position lower than the upper surface 41c of the dress board 41 by a minute depth δ. At this time, the cutting blade 36 may be positioned outside the dress portion 41a, or may be cut into the dress portion 41a.

[0107] In this state, while supplying cutting water (not shown) at a predetermined flow rate from each of the cooler nozzles 40a and the shower nozzle 42a, the cutting blade 36 and the chuck table 10 are moved relatively at a predetermined speed along the Y-axis direction (i.e., indexed feed). This performs dressing on the cutting blade 36. An example of processing conditions in the flat dressing steps S25 and S35 is shown below.

[0108] Spindle speed: 20,000 rpm Cooler nozzle cutting water flow rate: 1.0L / min (total flow rate of each cooler nozzle) Shower nozzle cutting water flow rate: 1.0L / min Indexing feed speed: 30mm / s

[0109] In the flat dressing steps S25 and S35, for example, a machined groove is formed by moving the cutting blade 36 from one end to the other end in the Y-axis direction of the dressing portion 41a. At this time, since a force is applied to the cutting blade 36 in a direction along the thickness direction 36c of the cutting blade 36 (see FIG. 14(B)), the cutting blade 36 is likely to crack.

[0110] Therefore, at the start of the flat dressing processes S25 and S35, the position of the lower end 36b of the cutting blade 36 in the Z-axis direction may be set slightly higher than the upper surface 41c of the dressing portion 41a, and then the lower end 36b may be lowered by a predetermined index amount when the cutting blade 36 is moved once along the Y-axis direction across the dressing portion 41a.

[0111] For example, the cutting blade 36 is moved once along the Y-axis direction so as to cross the dressing portion 41a, and then the lower end 36b is moved downward by a predetermined index amount along the Z-axis direction, and the cutting blade 36 is again moved along the Y-axis direction so as to cross the dressing portion 41a, and this operation is repeated multiple times.

[0112] In this manner, by dressing the cutting blade 36 while gradually lowering the lower end 36b of the cutting blade 36, the force applied in the direction along the thickness direction 36c of the cutting blade 36 can be reduced compared to when the lower end 36b is positioned at a relatively deep position relative to the upper surface 41c of the dressing portion 41a from the beginning.

[0113] The combination of the predetermined index amount and the number of repetitions is, for example, 20 μm and 15 times (first sequence), and is, for example, 5 μm and 40 times (second sequence).

[0114] After the machining groove is formed, the cutting blade 36 may be further dressed by moving the cutting blade 36 to a different area of ​​the dressing portion 41a. For example, after the first sequence, a second sequence is performed in a different area from the area used in the first sequence.

[0115] Figure 14(A) is a schematic diagram of the vicinity of the outer peripheral side surface in a cross section taken along a plane passing through the radial center of the cutting blade 36 before the flat dressing processes S25 and S35, and Figure 14(B) is a schematic diagram of the vicinity of the outer peripheral side surface in a cross section taken along a plane passing through the radial center of the cutting blade 36 after the flat dressing processes S25 and S35.

[0116] In the second embodiment, the outer peripheral side surface of the cutting blade 36 is made substantially flat as shown in Fig. 14(B). When the cutting blade 36 shown in Fig. 14(A) is used, substantially one point of the lower end 36b contacts the end face 11c1 of the tip 11, but when the cutting blade 36 shown in Fig. 14(B) which has been flat-dressed is used, the entire lower end 36b which is substantially flat across the width of the cutting blade 36 contacts the end face 11c1.

[0117] Therefore, the load on the cutting blade 36 in the grinding step S40 can be distributed in the thickness direction 36c of the cutting blade 36. Therefore, if the processing conditions such as the rotation speed and the indexing feed speed are the same, the use of the cutting blade 36 that has been subjected to the flat dress steps S25, S35 can suppress cracking, chipping, etc. of the cutting blade 36 in the grinding step S40 compared to the use of a cutting blade 36 that has not been subjected to the flat dress steps S25, S35.

[0118] (Third embodiment) In the above-described embodiment and modified examples, the first holding step S10 to the polishing step S40 are performed using one cutting device 2, but it is also possible to use a cutting device 2 (hereinafter, for convenience, referred to as cutting device 2b, but not shown) that is separate from the cutting device 2 (hereinafter, for convenience, referred to as cutting device 2a, but not shown).

[0119] In factories, etc., it is common practice to use multiple cutting devices 2 to cut the workpiece 21 simultaneously in parallel, and if the first holding step S10 through the polishing step S40 are performed using multiple existing cutting devices 2, there is no need to use either a polishing device or a grinding device.

[0120] The cutting device 2a includes a spindle (first spindle) 34 and a chuck table (first holding table) 10. A cutting blade (first cutting blade) 36 for the dividing step S20 is attached to the spindle 34 of the cutting device 2a. This cutting blade 36 has, for example, abrasive grains of a grain size of #1200 and a metal bond binder.

[0121] In this embodiment, the first holding step S10 and the dividing step S20 are performed using a cutting device 2a, and the workpiece 21 is divided into a plurality of chips 11. The subsequent second holding step S30 and polishing step S40 are performed using a cutting device 2b.

[0122] The cutting device 2b includes a spindle (second spindle) 34 and a chuck table (second holding table) 10. A cutting blade (second cutting blade) 46 for the polishing step S40 is attached to the spindle 34 of the cutting device 2b, and this cutting blade 46 has, for example, abrasive grains of a grain size of #2000 and a vitrified bond binder.

[0123] That is, the cutting blade 46 mounted on the spindle 34 of the cutting device 2b is different from the cutting blade 36 mounted on the spindle 34 of the cutting device 2a. In addition, the chuck table 10 of the cutting device 2b is also different from the chuck table 10 of the cutting device 2a.

[0124] The manufacturing method of the chip 11 of this embodiment can be performed using multiple existing cutting devices 2, and therefore the cost required to manufacture the chip 11 having the mirror-finished end surface 11c1 can be reduced compared to the case where a polishing device or grinding device is used in addition to the cutting device 2.

[0125] In this embodiment as well, flat dressing steps S25 and S35 in which the cutting blade 46 is dressed using the dressing board 41 can be adopted after the dividing step S20 and before the grinding step S40.

[0126] (Fourth embodiment) In the fourth embodiment, the first holding step S10 to the polishing step S40 are performed using one cutting device 2c having a so-called dual-spindle structure. Fig. 15 is a partially sectional side view showing the cutting device 2c having the dual-spindle structure.

[0127] The cutting device 2c includes a cutting unit 30a having a spindle (first spindle) 34a on which a cutting blade (first cutting blade) 36 for the dividing process S20 is mounted, a cutting unit 30b having a spindle (second spindle) 34b on which a cutting blade (second cutting blade) 46 for the polishing process S40 is mounted, and a chuck table (first holding table, also serving as a second holding table) 10.

[0128] The cutting blade 36 has, for example, abrasive grains of #1200 grit size and a metal bond binder, and the cutting blade 46 has abrasive grains of #2000 grit size and a vitrified bond binder. In other words, the cutting blade 46 attached to the spindle 34b is different from the cutting blade 36 attached to the spindle 34a.

[0129] In this embodiment, after the first holding step S10, a dividing step S20 is performed using the spindle 34a and the cutting blade 36, and then, after the second holding step S30, a grinding step S40 is performed using the spindle 34b and the cutting blade 46.

[0130] In this embodiment as well, the cost required to manufacture the tip 11 having the mirror-finished end surface 11c1 can be reduced compared to the case where a polishing device or a grinding device is used in addition to the cutting device 2.

[0131] In this embodiment as well, flat dressing steps S25 and S35 in which the cutting blade 46 is dressed using the dressing board 41 can be adopted after the dividing step S20 and before the grinding step S40.

[0132] In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. For example, the chip 11 does not need to have the optical waveguide 15. The chip 11 may or may not have a device such as an IC (Integrated Circuit) or a MEMS (Micro Electro Mechanical Systems) device.

[0133] Incidentally, in the second holding step S30, the chip 11 may be fixed directly to the dicing tape 33 using the wax 31a without using the substrate 31. The dicing tape 33 may be deformed when heated to melt the wax 31a. If the dicing tape 33 is deformed, a new dicing tape 33 may be used.

[0134] In the above embodiment, the workpiece 21 is divided into a plurality of chips 11 only by cutting using the cutting devices 2 and 2c. However, as long as the optical waveguide 15 of the workpiece 21 is divided by cutting and neither a polishing device nor a grinding device is used, the support substrate 13 of the workpiece 21 may be divided by cleavage if the support substrate 13 has crystallinity.

[0135] In addition, since the cutting edges 36a, 46a of new (i.e., unused) cutting blades 36, 46 usually have abrasive grains embedded in the binder, the outer peripheral side surfaces of the cutting edges 36a, 46a may be dressed to allow the abrasive grains to properly protrude from the binder.

[0136] If the polishing process S40 is performed using either the front or back surface of the approximately flat cutting blades 36a, 46a located in a position sandwiching the outer peripheral side surfaces of the cutting blades 36a, 46a in the thickness direction of the cutting blades 36a, 46a, a special technique is required to dress the front or back surface of the cutting blades 36a, 46a.

[0137] In contrast, when the grinding process S40 is performed using the outer peripheral side surfaces of the cutting blades 36a, 46a, the abrasive grains can be properly protruded from the bonding material by dressing using a general dressing board 41 shown in Figures 12 and 13. [Explanation of symbols]

[0138] 2,2c: Cutting equipment 4: base, 4a: opening, 6: table cover, 8: cover member 10: Chuck table (first holding table, second holding table) 10a: holding surface, 10b: clamp unit 11: chip, 11a: front surface, 11b: back surface, 11c1, 11c2: end faces 12: Support structure, 14: Y-axis and Z-axis direction movement mechanism 13: Support substrate, 15: Optical waveguide 16: Y-axis guide rail, 18: Y-axis moving plate, 20: screw shaft 17: core, 19a: lower clad, 19b: upper clad 21: Workpiece, 21a: Front surface, 21b: Back surface 21c: planned division line, 21d: rectangular area 22: Z-axis guide rail, 24: Z-axis moving plate, 26: screw shaft 23: dicing tape, 25: annular frame, 27: workpiece unit 28: Z-axis direction drive source 30, 30a, 30b: cutting unit, 32: spindle housing 31: substrate, 31a: wax, 31b: one side, 31c: other side 34: Spindle (first spindle, second spindle) 34a: spindle (first spindle), 34b: spindle (second spindle) 33: dicing tape, 35: annular frame, 37: chip unit 36: Cutting blade (first cutting blade) 36a: cutting edge, 36b: lower end, 36c: thickness direction 38: blade cover, 40: nozzle unit, 40a: cooler nozzle 41: dress board, 41a: dress part, 41b: substrate, 41c: upper surface 42: nozzle unit, 42a: shower nozzle 43: dicing tape, 45: annular frame, 47: dress board unit 44: Microscope camera unit 46: cutting blade (second cutting blade), 46a: cutting edge, 46b: lower end S10: First holding process, S20: Division process S30: Second holding process, S40: Polishing process S25, S35: Flat dress process Δ, δ: minute depth, θ: angle

Claims

1. A method for manufacturing a chip, comprising the steps of: polishing an end face of a chip separated from a workpiece by cutting to produce a chip having a mirror-finished end face, a first holding step of holding the workpiece on a first holding table; a dividing step of cutting the workpiece into a plurality of chips by relatively moving a first cutting blade that rotates around a first spindle as a rotation axis and the first holding table along a processing feed direction perpendicular to the longitudinal direction of the first spindle after the first holding step; a second holding step of holding at least one chip of the plurality of chips on a second holding table so that an end surface exposed by cutting is exposed upward after the dividing step; a grinding step of grinding the end surface with a lower end of a second cutting blade that rotates around a second spindle as a rotation axis, by relatively moving the second cutting blade and the second holding table along an indexing feed direction that is a longitudinal direction of the second spindle, while cutting into the end surface with the lower end of the second cutting blade that rotates around a second spindle as a rotation axis after the second holding step; A method for manufacturing a chip, comprising:

2. a flat dressing step of dressing the first cutting blade by relatively moving the first cutting blade and the first holding table along the longitudinal direction of the first spindle while positioning a lower end of the first cutting blade rotating around the rotation axis at a position lower than an upper surface of a dress board held by the first holding table after the dividing step and before the grinding step, 2. The method of claim 1, wherein the second cutting blade is identical to the first cutting blade.

3. a flat dressing step of dressing the second cutting blade by relatively moving the second cutting blade and the second holding table along the indexing feed direction while positioning the lower end of the second cutting blade rotating around the rotation axis at a position lower than an upper surface of a dress board held by the second holding table after the dividing step and before the grinding step; 2. The method of claim 1, wherein the second cutting blade is different from the first cutting blade.

4. 2. The method for producing a chip according to claim 1, wherein in the polishing step, two end faces located at opposing positions among the four end faces of the at least one chip are polished in sequence.

5. Each of the at least one chip includes an optical waveguide having a core through which light propagates and a cladding for confining the light to the core; The method for manufacturing a chip as described in claim 4, characterized in that the core is exposed at the two end faces polished in the polishing process, one of the two end faces corresponds to an incident face of light into the optical waveguide, and the other of the two end faces corresponds to an exit face of light from the optical waveguide.

6. A method for manufacturing a tip as described in any one of claims 1 to 5, characterized in that in the polishing process, the end surface is polished while the second cutting blade and the at least one tip are positioned so that they intersect each other when the second holding table is viewed in a plane.

7. 2. The method for manufacturing chips according to claim 1, wherein in the second holding step, the at least one chip fixed to a substrate or a dicing tape using wax is held by the second holding table.

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