JP2010076053A - Cutting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting device in which productivity is not lowered even when performing kerf inspection. <P>SOLUTION: The cutting device includes a chuck table holding a workpiece, a cutting means rotatably supporting a cutting blade cutting the workpiece held by the chuck table, an image pickup means picking up an image of the workpiece held by the chuck table, and an X-axis feed mechanism relatively moving the chuck table in an X-axis direction with respect to the workpiece to position the chuck table to the cutting means and the image pickup means, and to feed the chuck table for machining. The image pickup means is provided with an objective lens facing an image pickup area, an image pickup camera disposed on an optical axis of the objective lens, a strobe light source radiating a strobe light to the image pickup area, and an image processing part processing the image picked up by the image pickup camera. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cutting apparatus including an imaging unit capable of confirming a state of a cutting groove of a workpiece such as a semiconductor wafer.

  A semiconductor wafer formed in a region where a plurality of devices such as IC, LSI, etc. are partitioned by a division planned line is divided into individual devices by a cutting apparatus in which a cutting blade is rotatably mounted. Used for electronic devices such as telephones and personal computers.

  The cutting apparatus includes a chuck table that holds a workpiece such as a wafer, a cutting unit (cutting means) that rotatably supports a cutting blade that cuts the workpiece held on the chuck table, and a chuck table. An image pickup unit (image pickup means) that performs an alignment by picking up an image of the held work piece, detecting a division line to be cut, and moving the chuck table relative to the work piece in the X-axis direction In addition, an X-axis feed mechanism that is positioned on the cutting unit and the imaging unit and that feeds the workpiece is provided, so that the workpiece can be divided into individual devices with high accuracy.

By the way, when clogging occurs in the cutting blade, relatively large chips are generated on both sides of the cutting groove (kerf), leading to deterioration of the quality of the device. Therefore, the cutting groove formed on a workpiece such as a wafer during cutting. Is positioned directly below the imaging unit to check the state of the cutting groove (see Japanese Patent No. 2628256 and Japanese Patent Laid-Open No. 2008-4806).
Japanese Patent No. 2628256 Japanese Patent Laid-Open No. 2008-4806

  In the conventional cutting apparatus, the chuck table is stopped and the image captured by the imaging unit is captured in order to perform alignment by detecting the division line to be cut by the imaging unit. For this reason, there is a problem that it takes a relatively long time to perform alignment and productivity is poor.

  Further, in order to confirm the state of the cutting groove, there is a problem that productivity is poor because the cutting operation is temporarily stopped, the chuck table is positioned immediately below the imaging unit, and the image is captured by the imaging unit.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a cutting apparatus capable of quickly capturing an image by an imaging unit.

  According to the present invention, a chuck table for holding a workpiece, a cutting means for rotatably supporting a cutting blade for cutting the workpiece held on the chuck table, and a workpiece held on the chuck table And an X-axis feed mechanism that moves the chuck table relative to the workpiece in the X-axis direction to position the chuck table on the cutting means and the imaging means and feed the workpiece. The imaging means includes an objective lens that faces the imaging area, an imaging camera disposed on the optical axis of the objective lens, and a strobe light source that irradiates the imaging area with strobe light And an image processing unit that processes an image captured by the imaging camera.

  Preferably, the X-axis feed mechanism includes an X-coordinate detection unit that detects an X-coordinate value, and the X-coordinate detection unit is an X-coordinate value of an imaging region irradiated with strobe light in synchronization with a strobe signal of a strobe light source. Remember.

  Preferably, the imaging means includes a frame body that houses the imaging means, a partition wall having a light transmission window provided in the vicinity of the tip of the frame body, and the like. The cutting apparatus further includes water supply means for supplying water into a space partitioned by a frame, a partition, and a wafer held by a chuck table.

  According to the present invention, since the cutting device is configured to capture the image by irradiating the imaging area with the strobe light, it is necessary to stop the chuck table to capture the image when aligning the workpiece or checking the cutting groove. Productivity can be improved.

  Further, since the X coordinate value of the chuck table is stored in synchronization with the strobe light irradiation, the position of the captured image can be confirmed. Furthermore, when water supply means is disposed so as to fill water between the objective lens and the imaging region, even a workpiece wet with cutting water can be cut without being affected by water and / or cutting waste. A groove image can be captured.

  Hereinafter, a cutting device 2 according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration diagram of the cutting device 2. The cutting device 2 includes a pair of guide rails 6 that are mounted on the stationary base 4 and extend in the X-axis direction.

  The X-axis moving block 8 is moved in the machining feed direction, that is, the X-axis direction by an X-axis feed mechanism (X-axis feed means) 14 including a ball screw 10 and a pulse motor 12. A chuck table 20 is mounted on the X-axis moving block 8 via a cylindrical support member 22.

  The chuck table 20 has a suction part (suction chuck) 24 formed of porous ceramics or the like. A plurality of (four in this embodiment) clampers 26 for clamping the annular frame F shown in FIG.

  As shown in FIG. 2, the first street S1 and the second street S2 are formed orthogonal to each other on the surface of the semiconductor wafer W to be processed by the cutting apparatus 2, and the first street S1 A number of devices D are formed in a region partitioned by the second street S2.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer periphery of the dicing tape T is attached to an annular frame F. Thus, the wafer W is supported on the annular frame F via the dicing tape T, and is clamped on the annular frame F by the clamper 26 shown in FIG.

  The X-axis feed mechanism 14 includes a scale 16 disposed on the stationary base 4 along the guide rail 6, and a reading head 18 disposed on the lower surface of the X-axis moving block 8 that reads the X coordinate value of the scale 16. Including. The read head 18 is connected to the controller of the cutting device 2.

  A pair of guide rails 28 extending in the Y-axis direction are further fixed on the stationary base 4. The Y-axis moving block 30 is moved in the Y-axis direction by a Y-axis feed mechanism (index feed mechanism) 36 composed of a ball screw 32 and a pulse motor 34.

  The Y-axis moving block 30 is formed with a pair of guide rails 38 (only one is shown) extending in the Z-axis direction. The Z-axis moving block 40 is moved in the Z-axis direction by a Z-axis feed mechanism 44 composed of a ball screw (not shown) and a pulse motor 42.

  Reference numeral 46 denotes a cutting unit (cutting means), and a spindle housing 48 of the cutting unit 46 is inserted into and supported by the Z-axis moving block 40. The spindle housing 48 accommodates a spindle and is rotatably supported by an air bearing. The spindle is rotationally driven by a motor (not shown) housed in a spindle housing 48, and a cutting blade 50 is detachably attached to the tip of the spindle.

  An alignment unit (alignment means) 52 is mounted on the spindle housing 48. The alignment unit 52 has an imaging unit (imaging means) 54 that images the wafer W held on the chuck table 20. The cutting blade 50 and the imaging unit 54 are arranged in alignment in the X-axis direction.

  Next, the configuration of the imaging unit 54 according to the embodiment of the present invention will be described in detail with reference to FIG. The imaging unit 54 has a frame body 56 that houses an objective lens 68 that faces the imaging area, and a partition wall 58 having a light transmission window 59 is attached in the vicinity of the tip of the frame body 56.

  A water filling chamber 60 is defined in a space partitioned by the tip of the frame body 56, the partition wall 59, and the wafer W held on the chuck table 20. The distance between the tip 56a of the frame 56 and the wafer W held on the chuck table 20 is preferably about 0.5 to 1 mm. During the cutting of the wafer W, the water filling chamber 60 is filled with water from the water source 64 via the on-off valve 66 and the water supply port 62.

  The imaging unit 54 of this embodiment includes a strobe light source 70. A part of the strobe light emitted from the strobe light source 70 is reflected by the beam splitter 72 and irradiated onto the wafer W held on the chuck table 20 through the objective lens 68 and the light transmission window 59.

  On the optical axis of the objective lens 68, a CCD camera 74 that images the wafer W irradiated with strobe light is disposed. The image captured by the CCD camera 74 is input to the image processing unit 76 and subjected to image processing. The image processed by the image processing unit 76 is stored in the image storage unit 78.

  The output of the CCD camera 74 is simultaneously input to a monitor 82 such as an LCD, and the operator can check the state of the cutting groove (kerf) 84 displayed on the monitor 82. Reference numeral 86 denotes chipping formed in the cutting groove 84.

  The CCD camera 74 images the imaging area of the wafer W held on the chuck table 20 in synchronization with the light emission of the strobe light source 70. Further, the reading head 18 reads the X coordinate value of the scale 16 in synchronization with the light emission of the strobe light source 70, and the read X coordinate value is stored in the X coordinate storage unit 80.

  The operation of the imaging unit 54 configured as described above will be described below. First, the wafer W to be cut is sucked and held by the chuck table 20 and the X-axis feed mechanism 14 is driven to position the wafer W directly below the imaging unit 54.

  In the imaging unit 54 of the present embodiment, since the CCD camera 74 captures the imaging area of the wafer W in synchronization with the strobe light irradiation, a clear still image can be acquired even when the wafer W is still moving. it can.

  In the alignment of the wafer W to be cut, pattern matching based on a target pattern between an image stored in advance in the image processing unit 76 and an image acquired by the CCD camera 74 is performed on the same street while the chuck table 20 is rotated by θ. Implement at least two points along S1 or S2.

  Next, by aligning the cutting unit 46 in the Y-axis direction by the distance between the target pattern and the center line of the street S1 or S2, alignment for aligning the cutting blade 50 with the street S1 or S2 to be cut is achieved.

  When alignment is performed, the wafer W held on the chuck table 20 does not have cutting water or cutting debris attached thereto, so it is not necessary to supply water into the water filling chamber 60. In the imaging at the time of alignment by the imaging unit 54 of the present embodiment, the image is taken by the CCD camera 74 in synchronization with the irradiation of the strobe light from the strobe light source 70, so the wafer W held on the chuck table 20 is taken as the imaging unit. A still image can be taken even while moving under 54. As a result, the wafer W can be imaged quickly, and the time required for alignment can be shortened.

  When the alignment is completed, the street S1 is cut by cutting a predetermined amount to the dicing tape T through the wafer W with a cutting blade 50 that rotates at high speed while the chuck table 20 is processed and fed in the X-axis direction by the X-axis feed mechanism 14. .

  While driving the Y-axis feed mechanism 36 to index and feed the cutting blade 50, all the streets S1 in the same direction are cut. Next, the chuck table 20 is rotated 90 degrees to cut the street S2 that goes directly to the street S1.

  When it is desired to check the state of the cutting groove during the cutting of the wafer W, that is, when a kerf check is to be performed, the wafer W held on the chuck table 20 is driven directly below the imaging unit 54 by driving the X-axis feed mechanism 14. Position.

  The on-off valve 66 is opened to supply water into the water filling chamber 60, and the cutting waste and / or cutting water adhering to the wafer W is washed away with clean water. While constantly supplying water into the water filling chamber 60, the strobe light source 70 emits light to illuminate the imaging area of the wafer W with strobe light.

  Since the image is captured by the CCD camera 74 in synchronization with the light emission of the strobe light source 70, a beautiful still image can be captured by the CCD camera 74 even when the chuck table 20 is still moving. The image captured by the CCD camera 74 is subjected to image processing by the image processing unit 74, and the image processed image is stored in the image storage unit 78.

  Since the output of the CCD camera 74 is also input to the monitor 82 at the same time, the imaged cutting groove 84 is displayed on the monitor 82. The operator can observe the chipping 86 and the like generated in the cutting groove 84 while viewing the image on the monitor 82, and can confirm the state of the cutting groove 84.

  When the generation ratio of the chipping 86 formed on both sides of the cutting groove 84 increases, it is determined that the cutting blade 50 is clogged and the operator replaces the cutting blade 50 with a new cutting blade. Implement the following measures.

  The reading head 18 reads the X coordinate value of the scale 16 in synchronization with the light emission of the strobe light source 70 and stores it in the X coordinate storage unit 80. can do.

  When confirming the state of the cutting groove with the imaging unit 54 of this embodiment, that is, when performing a kerf check, the imaging area is defined by the CCD camera 74 in synchronization with the strobe light while supplying water into the water filling chamber 60. In order to capture an image, a still image can be captured by the CCD camera 74 even when the chuck table 20 is still moving. Therefore, the kerf check can be performed quickly, and even if the kerf check is performed, it is suppressed that the productivity is lowered.

It is a schematic block diagram of the cutting device of this invention embodiment. It is a perspective view of the semiconductor wafer hold | maintained at the cyclic | annular flame | frame via the dicing tape. It is a block diagram of the imaging unit of embodiment of this invention.

Explanation of symbols

2 Cutting device 14 X-axis feed mechanism 20 Chuck table 36 Y-axis feed mechanism 44 Z-axis feed mechanism 46 Cutting unit 50 Cutting blade 52 Alignment unit 54 Imaging unit 60 Water filling chamber 68 Objective lens 70 Strobe light source 74 CCD camera 76 Image processing unit 82 Monitor

Claims (3)

A chuck table for holding a workpiece, a cutting means for rotatably supporting a cutting blade for cutting the workpiece held on the chuck table, and an imaging means for imaging the workpiece held on the chuck table And an X-axis feed mechanism that moves the chuck table relative to the workpiece in the X-axis direction to position the chuck table on the cutting means and the imaging means and to feed the work. Because
The imaging means includes an objective lens facing the imaging area, an imaging camera disposed on the optical axis of the objective lens, a strobe light source that irradiates the imaging area with strobe light, and an image captured by the imaging camera. A cutting apparatus comprising: an image processing unit that processes an image. The X-axis feed mechanism includes an X-coordinate detection means for detecting an X-coordinate value;
2. The cutting apparatus according to claim 1, wherein the X-coordinate detecting means stores an X-coordinate value of an imaging region irradiated with strobe light in synchronization with a strobe signal of the strobe light source. The imaging means includes a frame body that houses the objective lens, and a partition wall having a light transmission window disposed in the vicinity of the front end portion of the frame body,
The cutting apparatus according to claim 1 or 2, further comprising water supply means for supplying water into a space partitioned by the frame, the partition, and a workpiece held on the chuck table.

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