JP5430359B2 - Alignment method - Google Patents

Description

  The present invention relates to an alignment method for detecting a processing scheduled line of a laminated workpiece.

  A ceramic chip capacitor sheet, which is a laminated workpiece in which green ceramic layers and electrode layers are alternately laminated, is processed and divided by a processing device such as a cutting device or a laser processing device, and then sintered to be a ceramic chip capacitor. Is formed.

  When processing a workpiece with these processing apparatuses, an alignment operation for detecting a processing line (processing position) of the workpiece in advance is performed. However, in a laminated workpiece such as a ceramic chip capacitor sheet, a processing line is not formed on the surface.

  Therefore, when processing such a laminated work, for example, a groove such as a V groove or a piece V groove in which only one of the side surfaces of the groove is inclined is formed in a part of the laminated work. These laminates are used as alignment marks.

  Then, based on these alignment marks, parallel processing of the processing means and the laminated work is performed, and an alignment operation for detecting a processing scheduled line is performed (for example, Japanese Patent Laid-Open Nos. 2000-252241 and 2004). -39906).

  In recent years, so-called auto-alignment, in which a processing apparatus automatically performs alignment work, has become mainstream. When carrying out auto-alignment, the alignment mark is stored in advance in the processing apparatus, and at the same time, the distance from the alignment mark to the planned processing line is stored.

  When processing the workpiece, the imaging unit of the processing apparatus images the workpiece to detect the alignment mark, and detects a processing scheduled line based on the alignment mark and a previously stored distance.

JP 2000-252241 A JP 2004-39906 A

  However, in the alignment mark formed by exposing the laminate, the alignment mark shape varies depending on the part of the laminated workpiece. Therefore, it is necessary to set the recognition threshold value low so that the processing apparatus recognizes that the alignment mark stored in advance and the alignment mark on the laminated workpiece to be processed are the same alignment mark.

  However, if the recognition threshold is set low, for example, only a part of the alignment mark may be mistakenly recognized as the alignment mark. If only a part of the alignment mark is recognized as the alignment mark, an incorrect position is detected as a planned processing line, the incorrect position is processed, and the workpiece is damaged.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an alignment method that does not damage a workpiece by accurately detecting a processing scheduled line.

According to the present invention, there is provided an alignment method for detecting a scheduled processing line of a laminated work, wherein first and second grooves are formed at end portions facing each other in a processing direction of the surface of the laminated work. An alignment mark forming step of exposing a plurality of bar-shaped laminates extending in a direction intersecting a processing direction in which a processing line extends in the groove of 2 and using the bar-shaped stacks as a pair of alignment marks; a center detection step of detecting respective center positions of the pair of the alignment marks in the indexing-feed direction perpendicular to, so that parallel and straight or processing-feed direction connecting said central position of the pair of alignment marks, and the piled workpieces parallel out step of performing parallel out of the processing means, after performing the parallel-out step, put in the indexing direction of the alignment mark And a planned processing line detection step of detecting the planned processing line spaced a predetermined distance indexing direction from the center position, said center detection step, a plurality of pixels in a matrix of the captured image captured the alignment mark imaging means An image dividing step in which a plurality of rows of pixels in which a plurality of pixels are arranged in the processing direction are arranged in a row in the indexing feed direction, and a pixel indicating the rod-shaped stack among the plurality of pixels is arranged in the row A count step for counting in the processing direction every time, and a histogram with the horizontal axis representing the index feed direction position and the vertical axis representing the direction in which the pixels indicating the rod-shaped laminate are arranged, are created based on the count number in the count step. A histogram creation step, and a centroid calculation step of calculating the centroid of the histogram to be the center position of the alignment mark. Alignment method of characterizing a Mukoto is provided.

  According to the present invention, the center position of a pair of alignment marks made up of a plurality of rod-like laminates is detected, and the laminated workpiece and the processing means are paralleled based on the center position, and then the planned processing line is based on the center position. Is detected. Therefore, since a processing scheduled line is not erroneously detected, it is possible to prevent a workpiece from being damaged by processing an incorrect position.

It is a perspective view of a cutting device suitable for applying the alignment method of the present invention. FIG. 2A is a side view showing the cutting blade of the first cutting means, and FIG. 2B is a side view showing the cutting blade of the second cutting means. FIG. 3A is a plan view of a ceramic chip capacitor sheet which is an example of a workpiece, and FIG. 3B is a plan view of the ceramic chip capacitor sheet in a state where V grooves are formed along four sides. It is a partial cross section side view of the ceramic chip capacitor sheet of the state supported by the annular frame via the dicing tape. It is explanatory drawing of a center position detection step. It is a partial cross section side view which shows a cutting process step.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, a perspective view of a cutting device (dicing device) 2 suitable for applying the alignment method of the present invention is shown.

  The cutting device 2 is a two-spindle type cutting device that sucks and holds a workpiece on the chuck table 4, and the chuck table 4 reciprocates in the cutting feed direction (X-axis direction) while indexing feed direction (Y-axis direction). And the work of the first cutting means 6 and the second cutting means 8 moving in the cutting feed direction (Z-axis direction).

  For example, when the ceramic chip capacitor sheet 70 is diced, as shown in FIG. 1, the ceramic chip capacitor sheet 70 supported by the annular frame F via the dicing tape T is placed on the chuck table 4 and sucked and held. Is done.

  The ceramic chip capacitor sheet 70 is configured by alternately stacking, for example, about 200 layers of raw ceramic layers and electrode layers formed of a metal such as palladium, and stacking the raw ceramic layers on the uppermost layer.

  The chuck table 4 is movable in the X-axis direction by the cutting feed means 10, and includes a first alignment means 12 and a second cutting that have a first imaging means 13 formed integrally with the first cutting means 6. The second alignment means 14 having the second image pickup means 15 formed integrally with the means 8 detects a planned division line that is a region to be cut of the ceramic chip capacitor sheet 70 sucked and held by the chuck table 4. Cutting is performed after the division line and the cutting blade are aligned in the Y-axis direction. Each of the first image pickup means 13 and the second image pickup means 15 is composed of a microscope and a CCD camera for picking up an image magnified by the microscope.

  The cutting feed means 10 includes a pair of X-axis guide rails 16 disposed in the X-axis direction, an X-axis movement base 18 slidably supported by the X-axis guide rails 16, and an X-axis movement base 18. An X-axis ball screw 20 that is screwed into a nut portion (not shown) formed on the X-axis, and an X-axis pulse motor 22 that rotationally drives the X-axis ball screw 20.

  The support base 24 that rotatably supports the chuck table 4 is fixed to the X-axis moving base 18, and is driven by the X-axis pulse motor 22 to rotate the X-axis ball screw 20. It is moved in the X-axis direction.

  On the other hand, the first cutting means 6 and the second cutting means 8 are supported by the guide means 26 so as to be indexable in the Y-axis direction. The guide means 26 includes a vertical column 28 disposed in the Y-axis direction orthogonal to the X-axis so as not to prevent movement of the chuck table 4 and a pair of Y disposed in the Y-axis direction on the side surface of the vertical column 28. A shaft guide rail 30, a first ball screw 32 and a second ball screw 34 arranged in parallel with the Y axis guide rail 30, and a first Y axis pulse motor connected to the first ball screw 32. 36 and a second Y-axis pulse motor 38 connected to the second ball screw 34.

  The Y-axis guide rail 30 supports the first support member 40 and the second support member 42 so as to be slidable in the Y-axis direction, and is provided in the first support member 40 and the second support member 42. Nuts (not shown) are screwed into the first ball screw 32 and the second ball screw 34, respectively.

  Driven by the first Y-axis pulse motor 36 and the second Y-axis pulse motor 38 and the first ball screw 32 and the second ball screw 34 rotate, respectively, the first support member 40 and the second The support members 42 are independently moved in the Y-axis direction.

  The positions of the first support member 40 and the second support member 42 in the Y-axis direction are measured by the linear scale 44 and used for precise control of the Y-axis direction positions. Although it is possible to provide a linear scale separately for each support member, it is better to measure the positions of both the first support member 40 and the second support member 42 with a single linear scale 44. It is possible to precisely control the distance between.

  A first moving member 46 to which the first cutting means 6 is attached is attached to the first support member 40 so as to be slidable in the vertical direction (Z-axis direction). The first Z-axis pulse motor When 48 is driven, the first moving member 46 is moved in the Z-axis direction.

  Similarly, a second moving member 50 to which the second cutting means 8 is attached is attached to the second support member 42 so as to be slidable in the vertical direction (Z-axis direction). By driving the shaft pulse motor 52, the second moving member 50 is moved in the Z-axis direction.

  Next, the configuration of the first cutting means 6 and the second cutting means 8 will be described with reference to FIG. As shown in FIG. 2 (A), a spindle 56 is rotatably accommodated in a spindle housing 54 of the first cutting means 6, and the tip of the spindle 56 has a V shape 60 on the outer periphery. One cutting blade 58 is detachably mounted.

  On the other hand, as shown in FIG. 2B, the second cutting means 8 has a spindle 64 rotatably accommodated in a spindle housing 62, and a second cutting blade 66 can be attached to and detached from the tip of the spindle 64. It is attached to.

  In this embodiment, in this way, the first cutting blade 58 having the tip V shape 60 is attached to the spindle 56 of the first cutting means 6, and the second cutting blade 66 is attached to the spindle 64 of the second cutting means 8. However, the second cutting blade 66 may be attached to the first cutting means 6 and the first cutting blade 58 may be attached to the second cutting means 8.

  Referring to FIG. 3 (A), a plan view of a ceramic chip capacitor sheet 70 that is a processing target of the present embodiment is shown. As described above, the ceramic chip capacitor sheet 70 is configured by alternately stacking, for example, about 200 raw ceramic layers and electrode layers before sintering, and stacking the raw ceramic layers on the uppermost layer. The electrode layer is formed as an electrode layer having a thickness of about 1 μm by screen printing a metal such as palladium on the surface of the raw ceramic layer.

  Since the uppermost layer of the ceramic chip capacitor sheet 70 is formed from a raw ceramic layer, generally no alignment mark is formed on the ceramic chip capacitor sheet 70.

  Therefore, as shown in FIG. 3B, the cutting blade 58 having the tip V shape 60 of the first cutting means 6 has V grooves 72a and 72b parallel to the respective sides in the vicinity of the four sides of the ceramic chip capacitor sheet 70. , 72c, 72d.

  Then, as shown in the enlarged view of FIG. 3B, the electrode 74 exposed on the inclined surface of the V groove 72a is used as an alignment mark. 73 is the lowest point of the V-groove 72a. When these V grooves 72a to 72d are formed, the ceramic chip capacitor sheet 70 is adhered to the dicing tape 76 as shown in FIG. 4, and the outer peripheral portion of the dicing tape 76 is adhered to the annular frame 78. With the sheet 70 supported by the annular frame 78, the V grooves 72 a to 72 d are cut by the cutting blade 58.

  As an alternative, a dicing tape having the same size as the ceramic chip capacitor sheet 70 may be attached to the back surface of the ceramic chip capacitor sheet 70 in order to reduce the amount of dicing tape used.

  In this case, in place of the chuck table 4 shown in FIG. 1, the ceramic chip capacitor sheet 70 is sucked and held by a chuck table having a suction area of the same size as the ceramic chip capacitor sheet 70, and cutting is performed.

  In the cutting device 2 shown in FIG. 1, the clamper that clamps the annular frame 78 after the ceramic chip capacitor sheet 70 is sucked and held by the chuck table 4 is omitted.

  In order to carry out the alignment for detecting the line to be divided of the ceramic chip capacitor sheet 70, it was previously exposed to the inclined surfaces of the V grooves 72a and 72b formed in the vicinity of the two sides facing the cutting device 2 in the first direction. A pair of opposing electrode groups 75 composed of a plurality of electrodes 74 is stored as an alignment mark 75 in the memory of the controller of the cutting apparatus 2. At the same time, the distance from the alignment mark 75 to the division planned line is also stored in the memory of the controller.

  When alignment is performed, the second imaging unit 15 of the second alignment unit 14 captures an image of a region including the pair of alignment marks 75 in the V grooves 72 a and 72 b and is orthogonal to the cutting direction in which the second cutting blade 66 cuts. The center position of the pair of alignment marks 75 in the index feed direction to be detected is detected.

  Next, the chuck table 4 is rotated so that the straight line connecting the pair of alignment marks 75 is parallel to the cutting direction of the second cutting blade 66, and a line separated from the center of the alignment mark 75 stored in advance by a predetermined distance. Detect as a line to be divided. The other planned division lines extending in the first direction are set based on the pitch of the planned division lines based on the design data.

  When the setting of the division planned line in the first direction is completed, the chuck table 4 is rotated 90 degrees to detect the division planned line extending in the second direction orthogonal to the first direction. For the detection of the division line extending in the second direction, an electrode group 75 composed of a plurality of electrodes 74 exposed on the inclined surfaces of the V grooves 72 c and 72 d facing in the second direction is used as a pair of alignment marks 75. And it detects similarly to the 1st direction. The detected division line is stored in the memory of the cutting device 2.

  However, the shape of the electrode 74, which is a rod-shaped laminate exposed in the V grooves 72 a to 72 d, varies depending on the portion of the ceramic chip capacitor sheet 70. Therefore, in the present invention, the center position in the index feed direction of the alignment mark 75 is detected, and this center position is used as the alignment mark to solve the problem caused by the variation in shape.

  That is, the second imaging unit 15 of the second alignment unit 14 captures an area including the pair of alignment marks 75 exposed on the inclined surfaces of the V grooves 72a and 72b facing in the first direction, and FIG. An alignment mark image 75a as shown in FIG. The alignment mark image 75a is composed of a plurality of electrode images 74a extending in the Y-axis direction intersecting the cutting direction (X-axis direction) in which the planned division line extends.

  Next, a center position detecting step for detecting the center position of the alignment mark image 75a in the indexing feed direction is performed. In this center position detection step, the alignment mark image 75a is divided into a plurality of pixels in a matrix. That is, the alignment mark image 75a is divided into a matrix so that a plurality of rows of pixels in which a plurality of pixels are arranged in the processing direction (X-axis direction) are arranged in the indexing feed direction (Y-axis direction).

  Then, among the plurality of pixels, the pixel indicating the electrode image 74a is counted in the processing direction for each row, and the position indicated in the indexing feed direction (Y-axis direction) is set on the horizontal axis based on the counted number, and the pixel indicated by the electrode image 74a A histogram 80 is created as shown in FIG.

  Next, as shown in FIG. 5C, a vertex 82 of the histogram 80 is connected to form a polygon 82, and the center of gravity G of the polygon 82 is used as an alignment mark in the index feed direction (Y-axis direction) of the alignment mark 75. The center position is 75. The center of gravity of the polygon 82 is detected using a conventionally known method.

  As described above, in the alignment method of the present invention, the center position in the index feed direction of the alignment mark made of a plurality of bar-shaped laminates having variations in shape can be accurately detected. Can be prevented, and it is possible to prevent an erroneous position from being detected as a division-scheduled line.

  After completion of the alignment operation, as shown in FIG. 6, the dividing line of the ceramic chip capacitor sheet 70 is cut using the second cutting blade 66 of the second cutting means 8, and the ceramic chip capacitor sheet 70 is cut into individual ceramic chips. Divide into capacitors.

  That is, as shown in FIG. 6, the division planned line to be cut detected by the alignment method of the present invention and the second cutting blade 66 are aligned, and the chuck table 4 is moved in the X1 direction in the aligned state. When the second cutting blade 8 is lowered while the second cutting blade 66 is rotated at a high speed in the A direction, the aligned division planned line is cut.

  By performing the cutting while feeding the second cutting means 8 in the Y-axis direction by the pitch of the planned division lines stored in the memory, all the planned division lines in the same direction are cut. Further, when the chuck table 4 is rotated 90 degrees and then the same cutting as described above is performed, all the division lines extending in the second direction are also cut, and the ceramic chip capacitor sheet 70 is divided into individual ceramic chip capacitors. The

  In the above-described embodiment, the example in which the ceramic chip capacitor sheet 70 is employed as the workpiece has been described. However, the alignment method of the present invention is not limited to this, and a general structure in which a plurality of layers are stacked. The present invention can be similarly applied to detection of a processing scheduled line of a typical laminated workpiece.

2 Cutting device 4 Chuck table 6 1st cutting means 8 2nd cutting means 13 1st image pickup means 15 2nd image pickup means 58 Cutting blade 66 having a tip V shape 66 Second cutting blade 70 Ceramic chip capacitor sheets 72a to 72d V Groove 74 Electrode 74a Electrode image 75 Alignment mark (electrode group)
75a Alignment mark image 80 Histogram 82 Polygon

Claims (1)

An alignment method for detecting a processing line of a laminated workpiece,
First and second grooves are formed at ends facing each other in the processing direction of the surface of the laminated workpiece, and the first and second grooves extend in a direction intersecting with the processing direction in which a processing scheduled line extends. An alignment mark forming step of exposing a plurality of rod-shaped laminates and using the rod-shaped laminate as a pair of alignment marks;
A center detecting step for detecting a center position of each of the pair of alignment marks in the indexing feed direction orthogonal to the processing direction;
A paralleling step for parallelizing the laminated workpiece and the processing means so that a straight line connecting the center positions of the pair of alignment marks is parallel to the processing feed direction ;
A planned machining line detecting step for detecting a planned machining line that is separated from the center position in the indexed feeding direction of the alignment mark by a predetermined distance in the indexed feeding direction after performing the parallelizing step ;
The center detection step divides a captured image obtained by imaging the alignment mark with an imaging unit into a plurality of pixels in a matrix, and a plurality of rows of pixels in which the plurality of pixels are arranged in the processing direction are continuous in the indexing and feeding direction. Image segmentation step to
A counting step of counting pixels indicating the rod-shaped laminate among the plurality of pixels in the processing direction for each row;
Based on the number of counts in the counting step, a histogram creation step for creating a histogram with the index feed direction position as the horizontal axis and the direction in which the pixels indicating the bar stack are aligned as the vertical axis;
Calculating the center of gravity of the histogram and calculating the center of gravity of the alignment mark as the center position;
An alignment method comprising:

Images