JP5172383B2 - Cutting blade detection mechanism - Google Patents

Description

  The present invention relates to a cutting blade detection mechanism in a cutting apparatus.

  A semiconductor wafer in which a number of devices such as IC and LSI are formed on the surface, and each device is partitioned by a line to be divided (street), the back surface is ground by a grinding machine and processed to a predetermined thickness. A dividing line is cut by a cutting device (dicing device) and divided into individual devices, which are used for electric devices such as mobile phones and personal computers.

  The cutting apparatus includes at least a chuck table that holds a semiconductor wafer and a cutting unit that cuts the wafer held on the chuck table, and can divide the semiconductor wafer into individual devices with high accuracy.

  In the cutting means, the light emitting part of the light emitting means and the light receiving part of the light receiving means are positioned so as to sandwich the cutting blade of the cutting blade, and the chipping or wear of the cutting edge is detected by a change in the amount of light received by the light receiving element of the light receiving means. A cutting blade detection mechanism is provided. When the cutting blade detection mechanism detects chipping or wear of the cutting blade, the cutting blade can be replaced as appropriate.

Cutting chips generated by cutting may adhere to the end faces of the light emitting part and the light receiving part, and chipping or wear of the cutting blade may not be detected properly. Is cleaned with a cleaner jig as disclosed in Utility Model Registration Publication No. 2511370, for example.
Utility Model Registration Gazette No. 2511370

  By the way, the cutting blade of the cutting blade protrudes from the circular base of the cutting blade by about 1 to 2 mm, and when the cutting blade detection mechanism is configured by a light beam having a diameter of about 1 mm, the cutting blade is detected to be broken or worn. Therefore, the end face of the light emitting part and the end face of the light receiving part are periodically moved in the center direction of the cutting blade following the wear of the cutting edge, and the end face of the light emitting part and the end face of the light receiving part are located near the tip of the cutting blade. Need to be positioned. Conventionally, since the operator has manually performed this by rotating the adjusting screw, there has been a problem that it is difficult to withstand troublesomeness.

  The present invention has been made in view of these points, and an object of the present invention is to provide a cutting blade detection mechanism that does not require the light emitting portion and the light receiving portion to be always positioned at an appropriate position with respect to the cutting blade of the cutting blade. Is to provide.

According to the present invention, there is provided a cutting table comprising a chuck table for holding a workpiece and a cutting means on which a cutting blade having a cutting edge for cutting the workpiece held on the chuck table is rotatably mounted. A cutting blade detection mechanism used in the apparatus, the light emitting means having a light emitting portion disposed on one side in the axial direction of the cutting blade so as to face the cutting blade, and facing the light emitting portion And a light receiving means having a light receiving portion disposed on the other side in the axial direction of the cutting blade, the light emitting means comprising a light emitting element and light dispersion for dispersing and averaging the light emitted from the light emitting element And a first optical fiber bundle in which a plurality of optical fibers that transmit light from the light dispersion element are bundled, and the light receiving means includes a light receiving element and a plurality of lights connected to the light receiving element. A second optical fiber bundle of fibers The light emitting unit is arranged in series in the radial direction so that a plurality of optical fibers branched from the first optical fiber bundle are adjacent to each other and cover the entire cutting blade of the cutting blade. The light receiving unit includes a plurality of optical fibers branched from the second optical fiber bundle so that each of the optical fibers of the light emitting series body faces the optical fibers in a one-to-one relationship. There is provided a cutting blade detection mechanism comprising a light receiving series body arranged in series in a radial direction so as to cover the entire cutting edge of the blade.

  According to the cutting blade detection mechanism of the present invention, since the plurality of optical fibers are adjacently arranged in series in the radial direction so as to cover the entire cutting blade of the cutting blade, the light emitting unit and the light receiving unit are configured, so that the cutting blade is worn out. Until then, there is no need to adjust the positions of the light emitting part and the light receiving part.

  Further, since the light dispersion element is provided between the light emitting element and the light emitting part, the light emitted from the light emitting element can be dispersed in the light dispersing element to make the light quantity uniform. There will be no variation in performance.

  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 device (dicing device) 2 that can divide a wafer into individual chips (devices).

  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 plurality of devices D are partitioned and 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.

  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, in which a spindle 26 that is rotationally driven by a servo motor (not shown) is rotatably accommodated. 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 peripheral portion.

  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.

  A blade detection block 50 having a round hole 52 is attached to the blade cover 30 by screwing a screw 54 into the screw hole 38 of the blade cover 30 through the round hole 52. A cutting blade detection mechanism 60 described later is attached to the blade detection block 50, and the state of the cutting blade 28a of the cutting blade 28 is detected by the cutting blade detection mechanism 60.

  With reference to FIG. 1, the operation of the cutting apparatus 2 configured as described above will be described. The wafer F accommodated in the wafer cassette 8 is sandwiched in the frame F by the loading / unloading means 10, the loading / unloading means 10 moves rearward (Y-axis direction), and the nipping is released in the temporary placement area 12. By this, it is placed in the temporary placement area 12. Then, the wafer W is positioned at a certain position by the positioning means 14 moving in a direction approaching each other.

  Next, the frame F is adsorbed by the transport unit 16, and the wafer W integrated with the frame F is transported to the chuck table 18 and held by the chuck table 18 as the transport unit 16 rotates. Then, the chuck table 18 moves in the X-axis direction, and the wafer W is positioned directly below the alignment means 20.

  The image used for pattern matching at the time of alignment in which the alignment unit 20 detects a street to be cut needs to be acquired in advance before cutting. Therefore, when the wafer W is positioned directly below the alignment unit 20, the imaging unit 22 captures the surface of the wafer W and causes the display unit 6 to display the captured image.

  Hereinafter, an outline of alignment by the imaging unit 22 will be described. The operator of the cutting device 2 operates the operation means 4 to search for a key pattern that is a target for pattern matching while slowly moving the image picked up by the image pickup means 22 and displayed on the display means 6. This key pattern uses, for example, a characteristic part of a circuit in the device D.

  When the operator determines a key pattern, an image including the key pattern is stored in a memory provided in the alignment unit 20 of the cutting apparatus 2. Further, the distance between the key pattern and the center line of the streets S1 and S2 is obtained by a coordinate value or the like and the value is also stored in the memory.

  Further, by slowly moving the captured image on the screen, an interval between the adjacent streets (street pitch) is obtained by a coordinate value or the like, and the street pitch value is also stored in the memory of the alignment means 20. .

  At the time of cutting along the street of the wafer W, the alignment unit 20 performs pattern matching between the stored key pattern image and the image actually acquired by the imaging unit 22. This pattern matching is performed at at least two points separated from each other along the same street S1 extending in the X-axis direction.

  First, while slowly moving the image picked up at point A on the screen, pattern matching between the stored key pattern and the actual image key pattern is performed, and the screen is fixed in a state where the key pattern is matched.

  When pattern matching is performed from the imaging screen at point A as described above, the chuck table 18 is moved in the X-axis direction, and pattern matching is performed at point B that is considerably separated from point A in the X-axis direction.

  At this time, instead of moving from point A to point B at once, pattern matching is performed, but pattern matching is performed as necessary at a plurality of points in the middle of movement to point B to correct the deviation in the Y-axis direction. It is preferable to slightly rotate the chuck table 18 to perform θ correction and finally perform pattern matching at point B.

  When the pattern matching at the points A and B is completed, the straight line connecting the two key patterns is parallel to the street S1, and the cutting means 24 is moved by the distance between the key pattern and the center line of the street S1. By moving in the Y-axis direction, the street to be cut and the cutting blade 28 are aligned.

  When the street to be cut and the cutting blade 28 are aligned, the chuck table 18 is moved in the X-axis direction, and the cutting means 24 is lowered while rotating the cutting blade 28 at a high speed. The street was cut.

  When the street is cut by the cutting blade 28, the street is cut while jetting cutting water from the cutting water supply nozzles 32 and 42 toward the cutting blade 28 and the wafer W. The cutting blade 28 is cooled by ejecting cutting water onto the cutting blade 28.

  By performing cutting while feeding the cutting means 24 in the Y-axis direction by the street pitch stored in the memory, all the streets S1 in the same direction are cut. Furthermore, when the chuck table 18 is rotated by 90 ° and then the same cutting as described above is performed, the streets S2 are all cut and divided into individual devices D.

  The wafer W that has been cut is moved in the X-axis direction by the chuck table 18 and is then gripped by the transfer means 25 that can move in the Y-axis direction and transferred to the cleaning device 27. The cleaning device 27 cleans the wafer by rotating the wafer W at a low speed (for example, 300 rpm) while jetting water from the cleaning nozzle.

  After the cleaning, the wafer W is dried by rotating the wafer W at a high speed (for example, 3000 rpm) to dry the wafer W, and then the wafer W is adsorbed by the conveying means 16 and returned to the temporary storage area 12, and the loading / unloading means 10, the wafer W is returned to the original storage location of the wafer cassette 8.

  Next, the configuration of the cutting blade detection mechanism 60 will be described with reference to FIGS. 5 and 6. As shown in FIG. 5, the cutting blade detection mechanism 60 has a fixed block (blade detection block) 50 fixed to the blade cover 30 and a movement that can move up and down with respect to the fixed block 50 by rotating an adjustment screw 55. Block 62 is included.

  As shown in FIG. 6, the light emitting means (light emitting assembly) 64 of the cutting blade detection mechanism 60 is connected to a light emitting element 66 composed of a light emitting diode (LED) or a laser diode (LD), and the light emitting element 66. A light dispersing element 68 made of a large-diameter plastic optical fiber or the like for dispersing and averaging the light emitted from the light emitting element 66 is included. For example, a first optical fiber bundle 70 in which a plurality of plastic optical fibers 72 having a diameter of 0.24 mm to 0.27 mm are bundled is connected to the light dispersion element 68.

  As shown in FIG. 5, the end of each optical fiber 72 is bent in the direction of the cutting edge 28 a of the cutting blade 28 with a bending radius equal to or larger than the minimum bending radius of the optical fiber 72. Is set to be perpendicular to the cutting edge 28a.

  As shown in FIG. 6, the light-emitting portion 74 of the light-emitting means 64 covers the entire cutting edge 28 a of the cutting blade 28 with the ends of the plurality of optical fibers 72 branched from the first optical fiber bundle 70 being adjacent to each other. Thus, it is comprised with the light emission series body arrange | positioned in series in radial direction. A transparent protective plate 76 made of sapphire or the like is attached to the light emitting unit 74.

  The light receiving means (light receiving assembly) 78 includes a light receiving element 80 such as a photodiode (PD) and a second optical fiber bundle 82 connected to the light receiving element 80. The second optical fiber bundle 82 is configured by bundling a plurality of plastic optical fibers 84 having a diameter of 0.24 mm to 0.27 mm, for example.

  The end of each optical fiber 84 constituting the light receiving unit 86 is bent with a predetermined curvature in the direction of the cutting edge 28a of the cutting blade 28. Each optical fiber 84 of the light receiving unit 86 is connected to each optical fiber 72 of the light emitting unit 74. It arrange | positions so that the emitted light may be received on a one-to-one basis.

  That is, the light receiving section 86 is arranged in series in the radial direction so that the ends of the plurality of optical fibers 84 are adjacent to each other and cover the entire cutting blade 28 a of the cutting blade 28, and each optical fiber constituting the light emitting section 74. 72, each of the optical fibers 84 receives light from 72. A transparent protective plate 88 made of sapphire or the like is attached to the light receiving unit 86.

  As shown in FIG. 6, the light emitting element 66 and the light receiving element 80 are connected to the controller 90 of the cutting apparatus 2, and parameters such as the light emission amount of the light emitting element 66 are controlled by the controller 90 and are photoelectrically converted by the light receiving element 80. The electrical signal is input to the controller 90.

  Hereinafter, the operation of the cutting blade detection mechanism 60 configured as described above will be described. The controller 90 drives the light emitting element 66 while the cutting blade 28 is rotating. The light emitted from the light emitting element 66 is dispersed and uniformed by the light dispersing element 68 and is uniformly incident on each optical fiber 72 constituting the first optical fiber bundle 70.

  As a result, light is emitted uniformly from each optical fiber 72 of the light emitting unit 74, and light that is not blocked by the cutting blade 28 a of the cutting blade 28 is received by the optical fiber 84 of the light receiving unit 86. Therefore, in the state indicated by the symbol A in which the cutting blade 28a of the cutting blade 28 is not worn, the amount of light received by the light emitting element 80 is small, and the amount of light received increases as it wears.

  Therefore, when cutting is continued by the cutting blade 28, the current value generated by the light receiving element 80 increases with time. As the cutting edge 28a wears, the amount of light received by the light receiving element 80 increases, and the current value also increases as shown in FIG.

  When the cutting blade 28a is worn to the position indicated by the symbol B and the current value of the light receiving element 80 reaches the use limit, the controller 90 displays the fact on the display means 6 and issues an alarm with a buzzer or the like to the operator. Inform. In response to this alarm, the operator replaces the cutting blade 28 with a new cutting blade.

  On the other hand, when chipping occurs in the cutting blade 28a during the cutting of the wafer by the cutting blade 28, the amount of light received by the light receiving element 80 increases instantaneously, so the current signal of the light receiving element 80 is shown in FIG. As shown by P, it increases instantaneously.

  Since the instantaneous increase in the current signal is displayed on the display means 6, the operator can recognize that the cutting blade 28 of the cutting blade 28 is chipped. Therefore, the operator replaces the cutting blade 28 with a new cutting blade.

  According to the embodiment described above, the cutting blade detection mechanism 60 is arranged in series in the radial direction so as to cover the entire cutting blade 28a of the cutting blade 28 with the ends of the plurality of optical fibers 72 and 84 being adjacent to each other. Since the light emitting unit 74 and the light receiving unit 86 are configured, after adjusting the positions of the light emitting unit 74 and the light receiving unit 86 with the adjusting screw 55, the positions of the light emitting unit 74 and the light receiving unit 86 are adjusted until the cutting blade 28a is worn. do not have to.

  Further, since the light dispersing element 68 is provided between the light emitting element 66 and the light emitting part 74, the light emitted from the light emitting element 66 can be dispersed in the light dispersing element 68 and the amount of light can be made uniform. There is no local variation in the amount of light emitted from the optical fiber 74.

It is an external appearance perspective view of a cutting device. It is a perspective view which shows the wafer integrated with the flame | frame. It is a disassembled perspective view of a cutting means. It is a perspective view of a cutting means. It is a figure which shows the structure of the mechanism part of a cutting blade detection mechanism. It is a mimetic diagram showing the whole cutting blade detection mechanism composition concerning an embodiment of the present invention. It is a graph which shows the relationship between cutting elapsed time and the electric current value of a light receiving element. It is a graph which shows the relationship between the cutting elapsed time at the time of detecting a chip | tip in a cutting blade, and the electric current value of a light receiving element.

Explanation of symbols

2 Cutting device 18 Chuck table 24 Cutting means 26 Spindle 28 Cutting blade 28a Cutting blade 60 Cutting blade detection mechanism 64 Light emitting means (light emitting assembly)
66 Light emitting element 68 Light dispersion element 70 First optical fiber bundle 72 Optical fiber 74 Light emitting part 78 Light receiving means (light receiving assembly)
80 light receiving element 82 second optical fiber bundle 84 optical fiber 86 light receiving portion

Claims (2)

Used in a cutting apparatus comprising a chuck table for holding a workpiece and a cutting means on which a cutting blade having a cutting edge for cutting the workpiece held on the chuck table is rotatably mounted. A cutting blade detection mechanism,
A light emitting means having a light emitting portion disposed on one side in the axial direction of the cutting blade so as to face the cutting blade;
A light receiving means having a light receiving portion disposed on the other side in the axial direction of the cutting blade so as to face the light emitting portion,
The light emitting means includes a light emitting element;
A light dispersing element that disperses and averages the light emitted from the light emitting element;
A first optical fiber bundle in which a plurality of optical fibers that transmit light from the light dispersion element are bundled;
The light receiving means includes a light receiving element;
A second optical fiber bundle in which a plurality of optical fibers connected to the light receiving element are bundled;
The light emitting unit is configured by a light emitting series body in which a plurality of optical fibers branched from the first optical fiber bundle are adjacent to each other and are arranged in series in the radial direction so as to cover the entire cutting blade of the cutting blade. And
The light receiving unit covers the entire cutting blade of the cutting blade so that each of the plurality of optical fibers branched from the second optical fiber bundle faces the respective optical fibers of the light emitting series body one-on-one. A cutting blade detection mechanism comprising a light receiving serial body arranged in series in a radial direction.   The cutting blade detection mechanism according to claim 1, wherein each of the light emitting series body and the light receiving series body includes a plurality of optical fibers having a diameter of 0.24 mm to 0.27 mm arranged in series.

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