JP5541657B2 - Sharpening board - Google Patents

Description

  The present invention relates to a dressing board for dressing a cutting blade for cutting a workpiece.

  A semiconductor wafer formed on the surface by dividing a plurality of devices such as IC, LSI, etc. by a division line formed in a lattice shape is divided into individual devices by a cutting apparatus having a cutting blade, and the divided devices Is widely used in various electric devices such as mobile phones and personal computers.

  The cutting apparatus includes at least a chuck table that holds a wafer, a cutting unit that rotatably supports a cutting blade that cuts the wafer held on the chuck table, and an alignment unit that detects a region to be cut. The wafer can be divided into individual devices with high accuracy.

  The cutting blade of the cutting blade is generally formed by fixing diamond abrasive grains with a nickel plating layer. As a workpiece such as a semiconductor wafer is cut, the diamond abrasive grains that have become old at the tip of the cutting blade fall out of the cutting blade, and as a result, the cutting blade always wears due to the self-generated blade action from which new diamond abrasive grains protrude. Cutting can be performed without reducing sharpness.

  However, when the cutting blade is worn and a new cutting blade is mounted on the spindle, or when the cutting blade is worn and needs to be sharpened, the sharpening board is cut with the cutting blade and the diamond plating layer is cut from the diamond plating layer. It is necessary to perform a sharpening operation to protrude the grains.

  Since the cutting edge of the cutting blade is not sufficiently adapted to the wafer only by the sharpening work for cutting the sharpening board, the applicant cuts the dummy wafer on which the device is not formed before cutting the wafer on which the device is formed. An automatic dicing system that automatically pre-cuts the cutting blade so that the diamond abrasive grains properly protrude from the nickel-plated layer by fully adapting the wafer to the wafer has been proposed (Japanese Patent No. 2628256).

Japanese Patent No. 2628256

  However, in the automatic dicing system described in Patent Document 1, the dummy wafer has to be cut about 400 times until the cutting edge of the cutting blade becomes familiar with the wafer, and it takes about 20 minutes and the productivity is poor. There is.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a sharpening board capable of efficiently providing the same effect as precutting simultaneously with sharpening of a cutting blade.

A superabrasive grain made of SiC is 55 to 65% by weight and a phenol resin containing a filler is kneaded at a ratio of 45 to 35% by weight to be formed into a plate shape and fired at a low temperature of 150 to 200 ° C. A sharpening board for sharpening a cutting blade having a cutting edge with diamond abrasive grains fixed by a nickel plating layer on the outer periphery, the thickness H of the test piece of the sharpening board being 1 mm, and the width W being 15 mm In this case, the test piece of the dressing board is supported by the first jig of two-point support in which the span Sd between the two points is 30 mm, and the span between the two points with respect to the test piece of the dressing board thus supported is supported. when Su is a force of G Newtons (N) by the second jig is 10mm, 3 (Sd-Su) G / 2WH bending strength determined at ² 60N / mm ² or more, 140 N / mm ² or less Specially Dressing board and is provided.

According to the present invention, superabrasive grains and a resin containing a filler are kneaded at an appropriate ratio so as to have a relatively low bending strength of 140 N / mm ² or less, molded into a plate shape, and fired at a low temperature. Since the dressing board is formed, if the dressing board is cut about 20 times, the cutting blade of the cutting blade can be fully adjusted to the wafer at the same time as the proper dressing. In the case of the conventional technology to be adapted to, the product which took about 20 minutes is shortened to about 1 minute, and the productivity can be greatly improved.

It is an external appearance perspective view of a cutting device. It is a perspective view of the semiconductor wafer supported by the annular frame via the dicing tape. It is a disassembled perspective view of a cutting means (cutting unit). It is a perspective view of a cutting means. It is a disassembled perspective view which shows a mode that a hub blade is attached to a spindle. It is a perspective view of the state where the hub blade is mounted on the spindle. It is a disassembled perspective view which shows a mode that a ring-shaped blade (washer blade) is attached to a spindle. It is a disassembled perspective view which shows a mode that a dressing board is affixed on the dicing tape with which the outer peripheral part was mounted | worn with the annular frame. It is explanatory drawing of the dressing operation | work using a dressing board. It is a schematic block diagram of a bending strength test apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an external view of a cutting apparatus 2 that includes a cutting blade suitable for sharpening with the sharpening board of the present invention and can divide a semiconductor wafer into individual chips (devices) with the cutting blade.

  On the front side of the cutting device 2, there is provided operating means 4 for an operator to input instructions to the device such as machining conditions. In the upper part of the apparatus, there is provided a display means 6 such as a CRT for displaying a guidance screen for an operator and an image taken by an imaging means described later.

  As shown in FIG. 2, on the surface of the wafer W to be diced, the first street S1 and the second street S2 are formed orthogonally, and the first street S1 and the second street S2 A large number of devices D are formed on the wafer W.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer peripheral edge of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the frame F via the dicing tape T, and a plurality of wafers (for example, 25 sheets) are accommodated in the wafer cassette 8 shown in FIG. The wafer cassette 8 is placed on a cassette elevator 9 that can move up and down.

  Behind the wafer cassette 8, a loading / unloading means 10 for unloading the wafer W before cutting from the wafer cassette 8 and loading the wafer after cutting into the wafer cassette 8 is disposed. Between the wafer cassette 8 and the loading / unloading means 10, a temporary placement area 12, which is an area on which a wafer to be carried in / out, is temporarily placed, is provided. Positioning means 14 for positioning at a certain position is provided.

  In the vicinity of the temporary placement area 12, transport means 16 having a turning arm that sucks and transports the frame F integrated with the wafer W is disposed, and the wafer W carried to the temporary placement area 12 is Adsorbed by the conveying means 16 and conveyed onto the chuck table 18 and sucked by the chuck table 18, and held on the chuck table 18 by fixing the frame F by a plurality of fixing means (clamps) 19. .

  The chuck table 18 is configured to be rotatable and reciprocally movable in the X-axis direction. Above the movement path of the chuck table 18 in the X-axis direction, an alignment unit 20 that detects a street to be cut of the wafer W is provided. It is arranged.

  The alignment unit 20 includes an imaging unit 22 that images the surface of the wafer W, and can detect a street to be cut by a process such as pattern matching based on an image acquired by imaging. The image acquired by the imaging unit 22 is displayed on the display unit 6.

  On the left side of the alignment means 20, a cutting means 24 for cutting the wafer W held on the chuck table 18 is disposed. The cutting means 24 is configured integrally with the alignment means 20, and both move together in the Y-axis direction and the Z-axis direction.

  The cutting means 24 is configured by attaching a cutting blade 28 to the tip of a rotatable spindle 26 and is movable in the Y-axis direction and the Z-axis direction. The cutting blade 28 is located on the extended line of the imaging means 22 in the X-axis direction.

  Reference numeral 25 denotes transport means for transporting the wafer W after cutting to the cleaning device 27. The cleaning device 27 cleans the wafer W and blows air from the air nozzle to dry the wafer W.

  Referring to FIG. 3, an exploded perspective view of the cutting means 24 is shown. FIG. 4 is a perspective view of the cutting means 24. Reference numeral 25 denotes a spindle housing of the cutting means 24, and a spindle 26 that is rotationally driven by a servo motor (not shown) is rotatably accommodated in the spindle housing 25. The cutting blade 28 is an electroformed blade, and has a cutting edge 28a formed by dispersing diamond abrasive grains in a nickel base material on the outer periphery thereof.

  A blade cover 30 covers the cutting blade 28, and a cutting water nozzle 32 extending along the side surface of the cutting blade 28 is attached thereto. Cutting water is supplied to the cutting water nozzle 32 through the pipe 34. The blade cover 30 has screw holes 36 and 38.

  A detachable cover 40 has a cutting water nozzle 42 that extends along the side surface of the cutting blade 28 when attached to the blade cover 30. The cutting water is supplied to the cutting water nozzle 42 via the pipe 44.

  The detachable cover 40 is fixed to the blade cover 30 by inserting the screw 48 into the round hole 46 of the detachable cover 40 and screwing it into the screw hole 36 of the blade cover 30. As a result, the upper half of the cutting blade 28 is covered with the blade cover 30 and the detachable cover 40 as shown in FIG.

  As shown in FIG. 5, a blade mount 56 is detachably attached to the tip of the spindle 26 of the cutting means 24. The blade mount 56 includes a boss portion 58 and a fixed flange 60 formed integrally with the boss portion 58, and a male screw 62 is formed on the boss portion 58. The blade mount 56 is fixed to the tip of the spindle 26 with a nut 64.

  The cutting blade 28 is called a hub blade, and is configured by electrodepositing a cutting edge 28 a in which diamond abrasive grains are dispersed in a nickel base material on the outer periphery of a circular base 66 having a circular hub 68. By inserting the mounting hole 70 of the cutting blade 28 into the boss portion 58 of the blade mount 56 and screwing the fixing nut 72 into the male screw 62 of the boss portion 58 and tightening, the cutting blade 28 is moved to the spindle 26 as shown in FIG. Attached to.

  Referring to FIG. 7, there is shown an exploded perspective view showing how the ring-shaped or washer-shaped cutting blade 74 is mounted on the spindle 26. The cutting blade 74 is composed of a cutting blade (electroforming grindstone) that is electroformed entirely.

  The cutting blade 74 is inserted into the boss portion 58 of the blade mount 56, the detachable flange 76 is further inserted into the boss portion 58, and the fixing nut 72 is screwed into the male screw 62 and tightened. And is attached to the spindle 26 by being sandwiched from both sides by the detachable flange 76.

  When the hub blade 28 or the washer blade 74 is replaced with a new blade, or when these blades are worn and need to be sharpened, the sharpening work of the hub blade 28 or the washer blade 74 is performed using the sharpening board. Is implemented. In this dressing operation, as shown in FIG. 8, a dressing board 78 having an outer peripheral portion attached to an adhesive tape (dicing tape) T attached to an annular frame F is used.

  As shown in FIG. 9, this sharpening operation is performed by moving the sharpening board 78 sucked and held by the chuck table 18 in the direction of arrow X and moving the cutting means 24 while rotating the cutting blade 28 at a high speed in the direction indicated by arrow A. This is performed by lowering and cutting the sharpening board 78 by cutting the cutting blade 28 into the sharpening board 78.

  The dressing board 78 of the present embodiment is a dressing board formed by impregnating a super-abrasive grain made of SiC into a phenolic resin and forming it into a plate shape and firing it at a low temperature of about 150 ° C. to about 200 ° C. It has a characteristic that it is softer than Preferably, the dressing board 78 contains 55 to 65% by weight of superabrasive grains made of SiC and 45 to 35% of phenol resin containing a filler by weight.

Furthermore, since the dressing board 78 of this embodiment is baked at a relatively low temperature, the bending strength is lower than that of a conventional dressing board. Bending strength is at 140 N (Newtons) / mm ² or less, preferably, 60N / mm ² or more 140 N / mm ² or less.

  Since the sharpening board 78 has such characteristics, when the sharpening board 78 is cut about 20 times by the cutting blade 28, the cutting edge 28a is cut by the semiconductor wafer W simultaneously with the sharpening of the cutting edge 28a of the cutting blade 28. Can get used to. As a result, the pre-cut that has been necessary for cutting the dummy wafer about 400 times can be omitted.

  Next, a bending strength test method for testing the bending strength of the sharpening board 78 according to the embodiment of the present invention will be described with reference to FIG. The bending strength test apparatus 80 includes a first jig 82 that supports a test piece 78 'of the dressing board and a second jig 84 that applies a pressing force to the test piece 78' of the dressing board.

  In the first jig 82, a pair of support portions 88 are erected on a plate 86, and a column 90 made of, for example, SUS having a diameter of 5 mm is attached to each support portion 88. The span Sd between the two points supporting the test piece 78 'of the dressing board is set to 30 mm. As for the size of the test piece 78 ′, the thickness H is 1 mm, the width W is 15 mm, and the length L is 40 mm.

  In the second jig 84, a pair of support portions 94 are erected on a plate 92, and each support portion 94 is equipped with, for example, a cylinder 96 made of SUS and having a diameter of 4 mm. The span Su between two points formed by the pair of cylinders 96 of the second jig 84 is 10 mm.

When the second jig 84 is fixed, the first jig 82 is raised in the direction of the arrow Z, and a G Newton (N) force is applied to the test piece 78 ′ by the pair of cylinders 96, the bending strength F is F = as defined in 3 (Sd-Su) G / 2WH 2. The bending strength test apparatus 80 is a four-point bending test apparatus.

The dressing board 78 of the present embodiment is required to have a bending strength obtained by 3 (Sd-Su) G / 2WH ² of 140 N / mm ² or less, preferably a bending strength of 140 N / mm ² or less, 60 N / mm ² or more.

  A dressing board having a thickness of 1 mm and a length and width of 75 mm was prepared, a cutting blade having a diameter of 52 mm and a cutting edge thickness of 30 μm was rotated at 30000 rpm, and cutting water was supplied at a rate of 2 liters / minute, and dressing was performed under the following conditions .

Rough centering step: Cutting depth 400 μm, feed rate 10 mm / sec, cutting frequency 1 time Finishing centering step: Cutting depth 400 μm, feed rate 40 mm / sec, cutting frequency 10 times Sharpening step: Cutting depth 200 μm, feed rate 70 mm / Second, 10 cuts

  The time required for the setting including the centering was about 1 minute. When a silicon wafer was cut with this cutting blade, a good cutting groove could be formed with few chips generated on both sides of the cutting groove.

In the embodiment described above, the superabrasive grains made of SiC and a phenol resin containing a filler are kneaded at an appropriate ratio so as to have a relatively low bending strength of 140 N / mm ² or less, and formed into a plate shape. Since the setting board 78 is formed by firing at a relatively low temperature, proper setting is performed by cutting the setting board 78 about 20 times. When the dummy wafer is cut and set by the conventional technique, the setting board 78 is about 20 minutes. The amount of time required was shortened to about 1 minute, and productivity was greatly improved.

28 Cutting blade (hub blade)
74 Washer blade 78 Sharpening board 78 ′ Sharpening board test piece 80 Folding strength test device 82 First jig 84 Second jig 90, 96 Ball

Claims (1)

A superabrasive grain made of SiC is 55 to 65% by weight and a phenol resin containing a filler is kneaded at a ratio of 45 to 35% by weight to be formed into a plate shape and fired at a low temperature of 150 to 200 ° C. A sharpening board for sharpening a cutting blade having a cutting edge with diamond abrasive grains fixed by a nickel plating layer on the outer periphery,
When the thickness H of the test piece of the dressing board is 1 mm and the width W is 15 mm, the test piece of the dressing board is supported by a two-point supported first jig whose span Sd between two points is 30 mm. When a force of G Newton (N) is applied to the test piece of the sharpening board supported by the second jig with a two-point span Su of 10 mm, 3 (Sd-Su) G / 2WH ² dressing board bending strength obtained is 60N / mm ² or more, characterized in that at 140 N / mm ² or less.

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