JP2012253298A - Process device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process device which adjusts the light amount of imaging means to the proper amount.SOLUTION: A process device includes: a chuck table holding a workpiece; process means processing the workpiece held on the chuck table; imaging means capturing images of the workpiece held on the chuck table; and process transferring means process transferring the chuck table and the process means relatively. The imaging means includes: a light source illuminating the workpiece; a camera capturing images of the illuminated workpiece; and a light amount adjuster adjusting the amount of light radiated from the light source. The light amount adjuster includes: a rotation plate having a rotation shaft; and an opening part formed in the rotation plate and transmitting the light radiated from the light source, and the opening part is formed into a flared shape so that the light amount transmitting therethrough continuously changes from a small amount to a large amount according to the rotation angle of the rotation shaft.

Description

  The present invention relates to a processing apparatus such as a cutting apparatus or a laser processing apparatus for processing a workpiece such as a semiconductor wafer.

  A wafer formed by dividing a plurality of devices such as IC, LSI, etc. by a line to be divided and formed on the surface thereof is divided into individual devices along the line to be divided by a dicing apparatus (cutting apparatus) or a laser processing apparatus. These devices are widely used in electric devices such as mobile phones and personal computers.

  A processing apparatus such as a dicing apparatus or a laser processing apparatus includes a chuck table that holds a workpiece such as a semiconductor wafer, a processing unit that processes the workpiece held on the chuck table, and a workpiece that is held on the chuck table. An image pickup means for picking up an image of the workpiece, and a work feed means for processing the chuck table and the work means relative to each other are provided.

  The imaging means generally includes a camera for imaging a workpiece and a microscope for enlarging an image captured by the camera, detects a planned division line that is an area to be processed, and accurately cuts a cutting blade or The laser processing head can be positioned on the division line to be processed.

  In the conventional processing apparatus, in order to perform alignment by detecting the division line to be processed by the imaging means, the chuck table is stopped and the area to be cut is imaged by the imaging means. However, it takes a relatively long time and productivity is poor.

  Accordingly, the applicant of the present application has disclosed an imaging means in which strobe light is used as a light source, and a CCD camera of the imaging means images a wafer imaging area in synchronization with the irradiation of the strobe light. Proposed in According to the cutting apparatus provided with this imaging means, a still image can be acquired even if the wafer is still moving.

JP 2010-76053 A

  However, the cutting apparatus having the imaging means disclosed in Patent Document 1 is not provided with means for adjusting the amount of strobe light emitted from the strobe light source. When imaging is performed without adjusting the amount of strobe light, there is a problem in that an appropriate captured image may not be obtained. In particular, when a xenon flash is used as a strobe light source, there is a problem that strobe imaging is almost impossible.

  The present invention has been made in view of these points, and an object of the present invention is to provide a processing apparatus including an imaging unit having a mechanism capable of adjusting the amount of light of a strobe light source.

  According to the present invention, a chuck table for holding a workpiece, a processing means for processing the workpiece held on the chuck table, an imaging means for imaging the workpiece held on the chuck table, A machining apparatus comprising a machining feed means for relatively machining and feeding the chuck table and the machining means, wherein the imaging means images a light source for illuminating the workpiece and the illuminated workpiece. And a light amount adjuster that adjusts the amount of light emitted from the light source. The light amount adjuster includes a rotating plate having a rotation axis and the rotating plate that transmits light emitted from the light source. The opening is formed in a divergent shape so that the amount of light that is transmitted continuously changes from small to large according to the rotation angle of the rotation shaft. An apparatus is provided.

  Since the processing apparatus of the present invention includes an imaging unit including a light amount adjuster having a divergent opening that changes the amount of light transmitted from the light source, the light amount from the light source is suitable for imaging the workpiece. The region to be processed of the workpiece can be imaged by adjusting to. In particular, it is advantageous when performing strobe imaging using a light source such as a xenon flash whose light intensity cannot be adjusted.

It is a schematic block diagram of the cutting device of this invention embodiment. It is a perspective view of the semiconductor wafer supported by the annular frame via the dicing tape. It is a schematic diagram explaining the structure and its effect | action of the imaging unit of this embodiment at the time of division plan line detection. 4A is a perspective view of the light amount adjuster, and FIG. 4B is a front view thereof. It is a schematic diagram which shows the effect | action of the imaging unit of this embodiment at the time of the state confirmation of a cutting groove.

  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 a 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 read 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 kerf check 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 xenon flash 70 that is a kind of strobe light source. A part of the strobe light emitted from the xenon flash 70 is reflected by the beam splitter 72 and applied to 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. An image captured by the CCD camera 74 is displayed on the monitor 76.

  Between the xenon flash 70 and the beam splitter 72, a light amount adjuster 82 that adjusts the amount of light emitted from the xenon flash 70 is disposed. As shown in FIG. 4, the light amount adjuster 82 includes a pulse motor 84, a rotating shaft 86 connected to the pulse motor 84, and a rotating plate 88 fixed to the tip of the rotating shaft 86.

  The rotating plate 88 is formed with an opening (gap) 90 that transmits light emitted from the xenon flash 70, and the opening 90 sets the amount of light transmitted according to the rotation angle of the rotating shaft 86 to a minimum value. It is formed in a divergent shape so as to change gradually (continuously) between the maximum values. That is, the opening 90 is formed such that the width gradually changes from one end 90a having a narrow width to the other end 90b having a large width.

  Referring again to FIG. 3, 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 xenon flash 70, and the captured image is displayed on the monitor 76. The xenon flash 70, the CCD camera 74 and the pulse motor 84 are connected to the control means 80 and are controlled by the control means 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 from the xenon flash 70, a clear still image is clear even if the wafer W is still moving. Can be obtained.

  When imaging the imaging area of the wafer W with the imaging unit 54, first, the pulse motor 84 of the light amount adjuster 82 is driven to rotate the rotating plate 88, and the xenon flash 70 transmitted through the opening 90 of the rotating plate 88 The driving of the pulse motor 84 is stopped at a position where the light quantity of the strobe light becomes the optimum position.

  The optimum position is determined by imaging the wafer W with the CCD camera 74 while observing the captured image with the monitor 76 while rotating the rotating plate 88 having the opening 90 by the pulse motor 84.

  After detecting a position where the amount of light transmitted through the opening 90 is optimal and fixing the rotating plate 88 at the position, an alignment process is performed. In the alignment process of the present embodiment, the wafer W held on the chuck table 20 by the X-axis feed mechanism 14 is moved in the X-axis direction, and a point on the wafer W (this point is referred to as A point) When it comes directly below, the xenon flash 70 is emitted to illuminate the imaging area of the wafer W.

  The device D at the point A is imaged by the CCD camera 74 in synchronization with the light emission of the xenon flash 70, the target pattern matching the image of the target pattern stored in advance in the alignment unit 52 is detected, and the target at the point A is detected. The coordinate value of the pattern is stored in the memory of the alignment unit 52.

  Next, the device D adjacent to the same street S1 as the street S1 imaged at the point A is imaged at the point B away from the point A by moving the chuck table 20, and the target pattern is detected by the same operation. The coordinate value of the target pattern at the point is stored in the memory of the alignment unit 52.

  Next, the chuck table 20 is rotated so that a straight line connecting the coordinate value of the target pattern at point A and the coordinate value of the target pattern at point B is parallel to the X-axis direction. Next, the cutting unit 46 is moved in the Y-axis direction by the distance between the target pattern and the center line of the street S1, thereby achieving alignment for aligning the cutting blade 50 with the street S1 to be cut.

  After the alignment of the first street S1, the chuck table 24 is rotated by 90 degrees, and the same operation is performed on the street S2 to perform the alignment of the second street S2.

  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 area to be cut of the wafer W is imaged by the CCD camera 74 in synchronization with the irradiation from the xenon flash 70, and therefore the wafer held on the chuck table 20. A still image can be captured even while W is moving under the imaging unit 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 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 is cut into the dicing tape T through the wafer W by a predetermined amount, thereby causing the first street S1. To cut.

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

  As shown in FIG. 5, 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 always supplying water into the water filling chamber 60, the xenon flash 70 is emitted 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 xenon flash 70, a beautiful still image can be captured by the CCD camera 74 even when the chuck table 20 is still moving.

  The output of the CCD camera 74 is input to the monitor 76, and the captured cutting groove 94 is displayed on the monitor 76. The operator can observe the chipping 96 and the like generated in the cutting groove 94 while viewing the image on the monitor 76, and can confirm the state of the cutting groove 94.

  When the generation ratio of the chipping 96 formed on both sides of the cutting groove 94 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.

  In the imaging at the time of alignment by the imaging unit 54 of the present embodiment, the chuck table is used to capture an area to be cut that is irradiated with an appropriate amount of light by the CCD camera 74 in synchronization with the strobe light irradiation from the xenon flash 70. A still image can be taken even while the wafer W held at 20 is moving under the imaging unit 54. As a result, the wafer W can be imaged quickly, and the time required for alignment can be shortened.

  When performing a kerf check, a chuck table is used to capture an imaging region irradiated with an appropriate amount of light by the CCD camera 74 in synchronization with the light emission of the xenon flash 70 while supplying water into the water filling chamber 60. Even if the camera 20 is still moving, a still image can be taken by the CCD camera 74. Therefore, the kerf check can be performed quickly, and even if the kerf check is performed, it is suppressed that the productivity is lowered.

  In the above-described embodiment, the example in which the imaging unit 54 of the present invention is applied to the cutting apparatus 2 has been described. However, the present invention is not limited to this, and the cutting unit 54 of the present invention is not limited to a laser processing apparatus or the like. The present invention can also be applied to the above processing apparatus.

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 Xenon flash 74 CCD camera 76 Monitor 82 Light intensity Adjuster 84 Pulse motor 88 Rotating plate

Claims (2)

A chuck table for holding a workpiece, a processing means for processing the workpiece held on the chuck table, an imaging means for imaging the workpiece held on the chuck table, the chuck table, and the chuck table A processing apparatus comprising a processing feed means for processing and feeding relative to the processing means,
The imaging means includes a light source that illuminates the workpiece, a camera that images the illuminated workpiece, and a light amount adjuster that adjusts the amount of light emitted from the light source,
The light amount adjuster includes a rotating plate having a rotating shaft, and an opening formed in the rotating plate that transmits light emitted from the light source.
The processing device according to claim 1, wherein the opening is formed in a divergent shape so that the amount of light transmitted in accordance with the rotation angle of the rotating shaft continuously changes from small to large.   The processing apparatus according to claim 1, wherein the light amount adjuster further includes a pulse motor coupled to the rotating shaft.

Images