JP2012250338A - Machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a machining device capable of appropriately adjusting a light incident angle according to a workpiece.SOLUTION: In the machining device, an image pickup means includes: a camera 94 for picking up an image of a workpiece W held on a chuck table 20; a half mirror 72; a first strobe light source 70 for illuminating the workpiece W; a plurality of optical fibers 112 annularly disposed; a second strobe light source 98 making light incident to the other end face of each of the plurality of optical fibers 112 to ring-irradiate the workpiece W held on the chuck table 20; a first light quantity adjustment device 82 disposed between the first strobe light source 70 and the half mirror 72; and a second light quantity adjustment device 100 disposed between the second strobe light source 98 and the other end face of each of the plurality of optical fibers 112. The first light quantity adjustment device 82 and the second light quantity adjustment device 100 include rotating plates 88 and 106 with rotary shafts, and openings. Each of the openings is formed into a shape widened toward the outside so that a light quantity transmitted according to a rotation angle of the rotary shaft continuously changes.

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

  In the imaging means disclosed in Patent Document 1, strobe light is irradiated perpendicularly to the workpiece held on the chuck table. When the workpiece is irradiated vertically by the strobe light in this way, there is a problem that the image picked up by the image pickup means may become unclear due to the intensity of the reflected light reflected by the workpiece.

  In addition, even when the captured image of the workpiece becomes unclear with vertical illumination, a clear captured image may be obtained when the workpiece is irradiated with light inclined with respect to the optical axis of the camera. The conventional imaging means has a problem that the light application cannot be adjusted as appropriate according to the workpiece.

  The present invention has been made in view of these points, and an object of the present invention is to provide a processing apparatus capable of appropriately adjusting the degree of illumination light applied to a workpiece held on a chuck table. It is.

  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, the imaging means comprising: a camera for imaging a workpiece held on the chuck table; A half mirror disposed on the optical axis of the camera, a first strobe light source for vertically illuminating a workpiece held on the chuck table via the half mirror, and one of the optical axes of the camera as a center. A plurality of optical fibers having an end face facing the workpiece held on the chuck table and arranged in an annular shape, and light is incident on the other end face of the plurality of optical fibers to enter the chuck table A second strobe light source for ring illumination of the workpiece to be held, a first light amount adjuster disposed between the first strobe light source and the half mirror, the second strobe light source and the plurality of lights A second light amount adjuster disposed between the other end surface of the fiber, each of the first light amount adjuster and the second light amount adjuster including a rotating plate having a rotation shaft, and the second light amount adjuster. An opening formed in the rotating plate that transmits the strobe light emitted from one strobe light source or the second strobe light source, and the opening has a small amount of light that is transmitted according to the rotation angle of the rotation shaft. There is provided a processing apparatus characterized in that it is formed in a divergent shape so as to change continuously.

  The processing apparatus according to the present invention includes an imaging unit that illuminates the workpiece by appropriately selecting vertical illumination or ring illumination, or combining both illuminations, so that the illumination light is applied to the workpiece. It can be optimally adjusted according to the workpiece, and a clear captured image can be obtained.

  In addition, since the light amount adjusters for adjusting the light amounts of the vertical illumination and the ring illumination are respectively provided correspondingly, it is possible to select a light amount suitable for imaging the workpiece. In particular, it is convenient when imaging using a strobe 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 bottom view of an objective lens unit. It is a schematic diagram explaining 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 with reference to FIG. The imaging unit 54 has a frame body 56 that houses an objective lens assembly 74 that faces the imaging area, and a partition wall 58 formed of a transparent body 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 front end portion of the frame 56, the partition wall 58, 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 objective lens assembly 74 includes an annular member 76 and an objective lens 78 accommodated in the annular member 76, and is placed on the transparent partition wall 58. As best shown in FIG. 5, the annular member 76 is formed with a plurality of through holes 77 arranged in an annular shape.

  Reference numeral 110 denotes an optical fiber bundle composed of a plurality of optical fibers 112, and one end of each optical fiber 112 is inserted into the through-hole 77 so as to face the wafer W held on the chuck table 20. Yes. The other end of the optical fiber 112 is connected to the transparent block 108.

  The imaging unit 54 of the present embodiment includes two xenon flashes 70 and 98 that are a kind of strobe light source. A part of the strobe light emitted from the xenon flash 70 is reflected by the half mirror 72 and applied to the wafer W held on the chuck table 20 via the objective lens 78 and the transparent partition wall 58.

  On the optical axis of the objective lens 78, a CCD camera 94 that images the wafer W irradiated with strobe light is disposed. An image picked up by the CCD camera 94 is displayed on a monitor 96.

  Between the xenon flash 70 and the half mirror 72, a light amount adjuster 82 for adjusting 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 94 captures 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 96. The xenon flash 70, the CCD camera 94 and the pulse motor 84 are connected to the control means 80 and are controlled by the control means 80.

  Between the other xenon flash 98 and the transparent block 108 to which the optical fiber bundle 110 is connected, a light amount adjuster 100 that adjusts the amount of light emitted from the xenon flash 98 is disposed.

  The light amount adjuster 100 has substantially the same structure as the light amount adjuster 82 shown in FIG. 4, and is fixed to the pulse motor 102, the rotating shaft 104 connected to the pulse motor 102, and the tip of the rotating shaft 104. And a rotating plate 106.

  The rotation plate 106 is formed with an opening, and the rotation shown in FIG. 4 is provided in the opening that changes the amount of light transmitted through the opening between the maximum value and the minimum value according to the rotation angle of the rotation shaft 104. The configuration is the same as that of the plate 88.

  When the xenon flash 98 emits light, the light adjusted to the optimum light amount by the light amount adjuster 100 enters the transparent block 108, propagates through the optical fiber 112, and has a plurality of through holes 77 arranged in a ring shape (annular shape). From the end face of the optical fiber 112 inserted into the wafer, illumination is performed in a ring shape toward the wafer W held on the chuck table 20. In this specification, the illumination from the xenon flash 98 will be referred to as ring illumination. On the other hand, illumination from the xenon flash 70 is referred to as vertical illumination.

  The CCD camera 94 images the imaging area of the wafer W held on the chuck table 20 in synchronization with the light emission of the xenon flash 98, and the captured image is displayed on the monitor 96. The xenon flash 98 and the pulse motor 102 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, the CCD camera 94 images the imaging area of the wafer W in synchronization with the irradiation of the strobe light from the xenon flashes 70 and 98. Therefore, even if the wafer W is still moving, it is clear. A still image can be acquired.

  When the imaging unit 54 images the imaging area of the wafer W, vertical illumination and ring illumination are appropriately selected according to the type of the wafer W or the like. Alternatively, since the wafer W can be illuminated using both vertical illumination and ring illumination, the degree of light application can be adjusted corresponding to the wafer W.

  When imaging with vertical illumination using the xenon flash 70, 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 is transmitted. The driving of the pulse motor 84 is stopped at a position where the light amount of the strobe light becomes the optimum position.

  The detection of the optimum position is determined by imaging the wafer W with the CCD camera 94 while rotating the rotating plate 88 having the opening 90 by the pulse motor 84 and observing the captured image on the monitor 96.

  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 94 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 94 in synchronization with the irradiation from the xenon flash 70, so that the wafer held on the chuck table 20 is captured. 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.

  Also in the case of ring illumination using the xenon flash 98, the CCD camera 94 images the imaging area of the wafer W illuminated in a ring shape in synchronization with the strobe light irradiation from the xenon flash 98. A clear still image can be acquired even while moving.

  Also in the case of ring illumination, after selecting the optimum segment of the light shielding plate mounted on the rotating plate 106 by the light amount adjuster 100, the alignment process is performed. Since the ring illumination using the xenon flash 98 is the same as the vertical illumination using the xenon flash 70, details of the alignment process are omitted.

  In the imaging unit 54 of this embodiment, the vertical illumination using the xenon flash 70 and the ring illumination using the xenon flash 98 can be appropriately selected, or both can be used together to illuminate the wafer W. Can be adjusted in accordance with the type of wafer W, and a clear captured image can be displayed on the monitor 96.

  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. 6, 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 xenon flash 70 or the xenon flash 98 is emitted to illuminate the imaging area of the wafer W with strobe light.

  Since the image is captured by the CCD camera 94 in synchronization with the light emission of the xenon flash 70 or the xenon flash 98, a beautiful still image can be captured by the CCD camera 94 even when the chuck table 20 is still moving.

  The output of the CCD camera 94 is input to the monitor 96, and the captured cutting groove 114 is displayed on the monitor 96. The operator can observe the chipping 116 and the like generated in the cutting groove 114 while viewing the image on the monitor 96, and can confirm the state of the cutting groove 114.

  When the generation ratio of the chipping 116 formed on both sides of the cutting groove 114 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 imaging at the time of alignment by the imaging unit 54 of the present embodiment, an area to be cut which is irradiated with an appropriate amount of light is imaged by the CCD camera 94 in synchronization with the strobe light irradiation from the xenon flash 70 or the xenon flash 98. Therefore, a still image can be captured even while the wafer W held on the chuck table 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.

  Further, when performing a kerf check, an imaging region irradiated with an appropriate amount of light is imaged by the CCD camera 94 in synchronization with light emission of the xenon flash 70 or the xenon flash 98 while supplying water into the water filling chamber 60. Therefore, a still image can be taken by the CCD camera 94 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.

  Furthermore, in this embodiment, the vertical illumination using the xenon flash 70 and the ring illumination using the xenon flash 98 are appropriately selected, or both are used to illuminate the wafer W held on the chuck table 20. Therefore, the degree of light application can be adjusted according to the type of wafer W, and a clear image can always be obtained by the CCD camera 94.

  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 Objective lens assembly 77 Through hole 78 Objective lens 82 Light amount adjuster 94 CCD camera 96 Monitor 98 Xenon flash 100 Light amount adjuster 112 Optical fiber

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 camera for imaging a workpiece held on the chuck table;
A half mirror disposed on the optical axis of the camera;
A first strobe light source that vertically illuminates the workpiece held on the chuck table via the half mirror;
A plurality of optical fibers arranged in an annular shape with one end face facing the workpiece held on the chuck table around the optical axis of the camera;
A second strobe light source for incident light on the other end face of the plurality of optical fibers to illuminate the workpiece held by the chuck table;
A first light amount adjuster disposed between the first strobe light source and the half mirror;
A second light amount adjuster disposed between the second strobe light source and the other end face of the plurality of optical fibers,
Each of the first light amount adjuster and the second light amount adjuster is formed on a rotating plate having a rotation axis and the rotating plate that transmits the strobe light emitted from the first strobe light source or the second strobe light source. Provided with an opening,
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 first and second light quantity adjusters further include a pulse motor connected to the rotating shaft.

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