JP2009083077A - Cutting blade detection mechanism - Google Patents

Abstract

A cutting blade detection mechanism capable of always positioning an emission end face of a light emitting portion and a light receiving end face of a light receiving portion at an appropriate position with respect to the cutting blade.
Cutting used in a cutting apparatus comprising a chuck table and a cutting means 28 rotatably mounted with a cutting blade having a cutting blade on the outer periphery for cutting a workpiece held on the chuck table. The blade detection mechanism 50 includes a light emitting unit 64, a light receiving unit 74 that receives light emitted from the light emitting unit 64, an emission end surface 72 of the light emitting unit 64, and a light receiving end surface 76 of the light receiving unit 74. A support means 60 for supporting the cutting blade 28a so as to sandwich the cutting blade 28a, and moving the support means 60 in the direction of the rotational axis of the cutting blade 28 in accordance with wear of the cutting blade 28a of the cutting blade 28; Positioning means for positioning the emission end face 72 of the light emitting portion 64 and the light receiving end face 76 of the light receiving portion 74 at appropriate positions with respect to the cutting blade 28a.
[Selection] Figure 6

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.

  The cutting means has a light emitting end surface and a light receiving end surface positioned so as to sandwich the cutting blade of the cutting blade, and a cutting blade detection that detects chipping or wear of the cutting blade by a change in the amount of light received by the light receiving element. A 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. Conventionally, when replacing the cutting blade, the end faces of the light emitting part and the light receiving part Is cleaned with a cleaner jig as disclosed in, for example, Utility Model Registration Publication No. 2511370.
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, following the wear of the cutting edge, the emission end face of the light emitting part and the light receiving end face of the light receiving part are periodically moved in the direction of the rotation axis of the cutting blade, and the emission end face of the light emitting part and It is necessary to position the light receiving end face of the light receiving unit. 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 the above points, and the object of the present invention is to always position the light emitting end surface of the light emitting portion and the light receiving end surface of the light receiving portion at appropriate positions with respect to the cutting blade of the cutting blade. A cutting blade detection mechanism is provided.

  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 an apparatus, comprising: a light emitting portion; a light receiving portion that receives light emitted from the light emitting portion; an emission end face of the light emitting portion; and a light receiving end face of the light receiving portion. Supporting means for sandwiching the cutting blade, and moving the supporting means in the direction of the axis of rotation of the cutting blade in accordance with wear of the cutting blade of the cutting blade, and the light emitting end surface and the light receiving portion And a positioning means for positioning a light receiving end face of the portion at an appropriate position with respect to the cutting blade.

  Preferably, the positioning means is detected by a light amount detection unit that detects a light amount received by the light receiving unit, a reference light amount storage unit that stores a reference light amount received by the light receiving unit, and the light amount detection unit. When the light amount detected by the light amount detection unit exceeds the light amount stored in the reference light amount storage unit by comparing the light amount and the light amount stored in the reference light amount storage unit, the support means is It comprises a support means feed section that feeds a predetermined amount in the direction of the rotational axis of the blade.

  Preferably, the apparatus further includes a wear management unit that manages wear of the cutting blade of the cutting blade based on the amount of light received by the light receiving unit, and the wear management unit includes a predetermined amount of the support unit by the support unit feeding unit. It has a feed amount storage unit for storing the feed amount when it is sent.

  According to the cutting blade detection mechanism of the present invention, the support means is moved in the direction of the rotation axis of the cutting blade in accordance with the wear of the cutting blade of the cutting blade, and the light emitting end surface of the light emitting unit and the light receiving end surface of the light receiving unit are used as the cutting blade. On the other hand, since it is positioned at an appropriate position, the labor of manually positioning the emission end face of the light emitting section and the light receiving end face of the light receiving section can be saved, and productivity can be improved.

  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.

  Reference numeral 50 denotes a blade detection block (blade detection mechanism), which is attached to the blade cover 30 by screws 54. A blade sensor (not shown) composed of a light emitting element and a light receiving element is attached to the blade detection block 50, and the state of the cutting edge 28a of the cutting blade 28 is detected by this blade sensor.

  When the chip of the cutting edge 28a is detected by the blade sensor, the cutting blade 28 is replaced with a new cutting blade. 55 is an adjusting screw for adjusting the position of the blade sensor. When replacing the cutting blade 28, the detachable cover 40 is removed from the blade cover 30 as shown in FIG. 3, and the cutting blade 28 is replaced in this state.

  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 at a high speed (for example, 3000 rpm) by blowing air from the air nozzle and drying the wafer W. Then, the wafer W is adsorbed by the conveying means 16 and returned to the temporary storage area 12, and then the loading / unloading means. 10, the wafer W is returned to the original storage location of the wafer cassette 8.

  Next, the structure of the mechanism part of the cutting blade detection mechanism 50 will be described with reference to FIG. The cutting blade detection mechanism (blade detection block) 50 includes a fixed block 58 fixed to the blade cover 30 and a moving block 60 that can move up and down with respect to the fixed block 58.

  A pulse motor 56 is mounted on the fixed block 58, and the output of the pulse motor 56 is coupled to a male screw rod 62, and the male screw rod 62 is screwed to a nut (not shown) formed on the moving block 60. When the pulse motor 56 is rotated, the moving block 60 moves up and down with respect to the fixed block 58 according to the rotation direction.

  The light emitting unit 64 of the blade detection mechanism 50 includes a light emitting element 66 composed of a light emitting diode (LED) or a laser diode (LD), an optical fiber 68 connected to the light emitting element 66, and a light attached to the moving block 60. A right-angle prism 70 that reflects light from the fiber 68 and a transparent protective plate 72 that is formed of sapphire and attached to the right-angle prism 70 are configured. The transparent protective plate 72 constitutes the emission end face of the light emitting unit 64. Therefore, in this specification, the transparent protective plate 72 is defined as the emission end face 72 of the light emitting unit 64.

  The light receiving unit 74 of the blade detection mechanism 50 includes a light receiving element 76 such as a photodiode (PD), an optical fiber 78 connected to the light receiving element 76, a right angle prism 80 attached to the moving block 60, and a right angle prism 80. It comprises a transparent protective plate 82 made of sapphire and the like. The transparent protective plate 82 constitutes the light receiving end face of the light receiving unit 74. Therefore, in this specification, the transparent protective plate 82 is defined as the light receiving end face 82 of the light receiving unit 74.

  In the detection position shown in FIG. 5, the light emitting end face 72 of the light emitting section 64 and the light receiving end face 82 of the light receiving section 74 are opposed to each other with an appropriate positional relationship so as to sandwich the cutting edge 28a of the cutting blade 28. Detects wear or chipping.

  Referring to FIG. 6, there is shown an overall configuration diagram of a cutting blade detection mechanism according to an embodiment of the present invention. The structure of the mechanism part is the same as that shown in FIG. In the present embodiment, the support block 60 is moved in the direction of the rotational axis of the cutting blade 28 according to the wear of the cutting blade 28 a of the cutting blade 28, and the light emitting end surface 72 of the light emitting unit 64 and the light receiving end surface 82 of the light receiving unit 74. Is provided with a positioning means for positioning at a suitable position with respect to the cutting edge 28a.

  The positioning means includes a light amount detection unit 86 that detects the amount of light received by the light receiving element 76, a reference light amount storage unit 88 that stores a reference light amount received by the light receiving element 76, and a light amount detected by the light amount detection unit 86. And the comparison unit 90 that compares the light amount stored in the reference light amount storage unit, and the light amount detected by the light amount detection unit 86 in the comparison unit 90 is determined to have exceeded the light amount stored in the reference light amount storage unit 88. A moving block feeding unit 92 that drives the pulse motor 56 by a predetermined number of pulses and feeds the support block 60 in the direction of the rotation axis of the cutting blade 28 by a predetermined amount.

  When the comparison unit 90 determines that the amount of light detected by the light amount detection unit 86 exceeds the amount of light stored in the reference light amount storage unit 88, the wear of the cutting blade 28a has advanced by a predetermined amount or more. Sometimes, it is necessary to move the moving block 60 in the axial direction of the cutting blade 28 so that the emission end face 72 of the light emitting section 64 and the light receiving end face 82 of the light receiving section 74 are positioned at appropriate positions with respect to the tip of the cutting blade 28a.

  Therefore, at this time, the pulse motor 56 is driven at a predetermined number of pulses in accordance with a command from the moving block feeding unit 92, and the emission end face 72 and the light receiving end face 82 are positioned at appropriate positions with respect to the tip of the cutting blade 28a. At the same time, the feed amount commanded by the moving block feed unit 92 is stored in the feed amount storage unit 96 of the wear management unit 94.

  In the wear management unit 94, the amount of light received by the light receiving element 76 increases as the cutting blade 28 a wears, so that the current value output from the light receiving element 76 gradually increases as indicated by reference numeral 98.

  When the wear of the cutting blade 28a reaches the limit value, the light amount detected by the light amount detection unit 86 exceeds the light amount stored in the reference light amount storage unit, so that the moving block sending unit 92 drives the pulse motor 56 to move the moving block. 60 is sent in the direction of the rotational axis of the cutting blade 28, and the emitting end face 72 and the light receiving end face 82 are positioned at appropriate positions.

  Therefore, at this time, the amount of light received by the light receiving element 76 is reduced, so that the current value output from the light receiving element 76 decreases as indicated by reference numeral 100. Therefore, when the moving block 60 is moved and moved a plurality of times, the current value in the wear management unit 94 changes in a sawtooth shape with the passage of time.

  Since the feed amount storage unit 96 stores the accumulated feed amount, for example, if the cumulative number of feeds reaches five times, it is determined that the cutting blade 28 has worn to the limit point, and the cutting blade 28 is replaced with a new cutting blade. Replace with.

  The output of the light receiving element 76 is input to the damage detection unit 84 at the same time as being input to the wear management unit 94. The breakage detector 84 detects chipping of the cutting blade 28a. When the current value increases in a spike shape as indicated by reference numeral 85, it is determined that chipping has occurred in the cutting blade 28, and the cutting blade 28 is replaced with a new one. Replace with a cutting blade.

  Needless to say, the cutting blade detection mechanism according to the embodiment of the present invention automatically detects the wear or chip of the blade while cutting the wafer with the cutting blade 28, and automatically emits light when the wear of the cutting blade 28a is detected. The emission end face 72 of the portion 64 and the light receiving end face 82 of the light receiving portion 74 can be positioned at appropriate positions with respect to the tip of the cutting blade 28a. Therefore, the labor for positioning the light emitting end face 72 of the light emitting section 64 and the light receiving end face 82 of the light receiving section 74 at appropriate positions can be saved, and the productivity of cutting the wafer is improved.

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 figure which shows the whole structure of the cutting blade detection mechanism which concerns on this invention embodiment.

Explanation of symbols

2 Cutting device 18 Chuck table 24 Cutting means 26 Spindle 28 Cutting blade 28a Cutting blade 50 Cutting blade detection mechanism 56 Pulse motor 60 Moving block 64 Light emitting part 66 Light emitting element 68, 78 Optical fiber 72 Light emitting end face 76 Light receiving element 82 Light receiving end face

Claims (4)

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 unit;
A light receiving unit that receives light emitted from the light emitting unit;
A support means for supporting the emission end face of the light emitting part and the light receiving end face of the light receiving part so as to sandwich the cutting blade of the cutting blade;
The support means is moved in the direction of the rotational axis of the cutting blade in accordance with wear of the cutting blade of the cutting blade, and the light emitting end surface of the light emitting unit and the light receiving end surface of the light receiving unit are suitable for the cutting blade. Positioning means for positioning at a position;
A cutting blade detection mechanism comprising:   The positioning means includes a light amount detection unit that detects a light amount received by the light receiving unit, a reference light amount storage unit that stores a reference light amount received by the light receiving unit, a light amount detected by the light amount detection unit, When the light amount detected by the light amount detection unit exceeds the light amount stored in the reference light amount storage unit by comparing with the light amount stored in the reference light amount storage unit, the support means rotates the cutting blade. 2. The cutting blade detection mechanism according to claim 1, wherein the cutting blade detection mechanism is constituted by a support means feeding portion that feeds a predetermined amount in the axial direction. Further comprising a wear management unit for managing wear of the cutting blade of the cutting blade based on the amount of light received by the light receiving unit;
3. The cutting blade detection mechanism according to claim 2, wherein the wear management unit includes a feed amount storage unit that stores a feed amount when the support means feed unit feeds the support means by a predetermined amount. .   The cutting blade detection mechanism according to any one of claims 1 to 3, further comprising a breakage detection unit that detects the breakage of the cutting blade of the cutting blade by monitoring the amount of light received by the light receiving unit.

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