JP6300645B2 - Processing equipment - Google Patents

Description

  The present invention relates to a processing apparatus such as a cutting apparatus or a laser processing apparatus.

  A semiconductor wafer in which a number of devices such as IC, LSI, etc. 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) to be divided into individual device chips, and the divided device chips are widely used in various electronic devices such as mobile phones and personal computers.

  In addition to the above-described cutting device and grinding device, there is a laser processing device as a processing device for processing a semiconductor wafer (hereinafter sometimes simply referred to as a wafer). In these various processing apparatuses, the wafer accommodated in the cassette is pulled out from the cassette and transported in the apparatus to perform various processing.

  For example, when a wafer is fully cut along the division line and the wafer is divided into individual device chips, the wafer unit is attached to a dicing tape whose outer periphery is attached to an annular frame to form a frame unit. Then, the wafer is housed in a cassette in the form of a frame unit, transported in the apparatus, and the wafer is cut while being held on the chuck table.

  However, in dicing before grinding, edge trimming, and laser processing that forms a modified layer inside the wafer, the wafer is transported alone, and half-cut, circular processing, and formation of the modified layer are performed on the wafer. Is called.

  In such a case, since the orientation of the wafer is scattered when housed in the cassette, a notch (notch or orientation flat) indicating the crystal orientation of the wafer when the wafer is transferred from the cassette to the chuck table. It was necessary to perform position detection and adjustment in advance.

  Further, in order to position the wafer center on the chuck table with the center of the wafer positioned at the center of the chuck table, it is also necessary to perform center alignment of the wafer.

  In order to satisfy this requirement, in the semiconductor wafer processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2005-11917, a position detection mechanism including a notch detection unit and a centering unit is provided below the cassette mounting table, and is carried out from the cassette. The processed wafer is once sent to the position detection mechanism, where the position detection and centering of the notch are performed, and then transported again and placed on the chuck table.

JP 2005-11917 A

  When a plurality of wafers are accommodated in a cassette as a single wafer and the wafer is processed as a single wafer, the wafer detecting device performs notch detection and centering using a position detection mechanism as disclosed in Patent Document 1, and then a transfer device. Then, it is transported again and placed on the chuck table.

  Therefore, it takes more time for adjustment work than a frame unit-shaped wafer. Further, there is a problem that the position of the warped wafer cannot be adjusted by the abutting means used for position adjustment.

  The present invention has been made in view of the above points, and the object of the present invention is to provide a simple structure for notching a wafer without providing a space for disposing a position detection mechanism. It is to provide a processing apparatus capable of detecting and detecting the center position.

  According to the present invention, a chuck table for holding a wafer on a holding surface, a processing means for processing the wafer held on the chuck table, a processing feed means for moving the chuck table in a processing feed direction, and a plurality of wafers. A cassette mounting table for mounting a cassette to be accommodated, a holding hand for unloading a wafer from the cassette mounted on the cassette mounting table, a wafer taken from the holding hand, held, and transferred to the chuck table An imaging means for capturing an image of the wafer including the outer periphery from the upper side while capturing the wafer unloaded from the cassette while being held by the holding hand; Calculation of the center position of the wafer held by the holding hand from the coordinates of three or more points on the outer periphery of the wafer in the captured image And the processing feed direction of the chuck table so that the center of the wafer is positioned at the center of the chuck table when the wafer picked up and held by the transfer hand is transferred to the chuck table. And a control means for controlling the movement distance of the transfer means, and a reflective material is disposed in an imaging region for imaging the wafer being unloaded from the cassette by the holding hand, and the reflective material Is positioned such that the wafer unloaded from the cassette passes above and has a width exceeding the diameter of the wafer in a direction perpendicular to the unloading direction of the holding hand, and the outer periphery of the wafer held on the holding surface of the holding hand. And a processing device characterized by being disposed in the region.

  Preferably, the wafer has a notch indicating a crystal orientation on an outer periphery, and the calculation means calculates an angle from a predetermined direction of the notch of the wafer held by the holding hand from the captured image, and the control The means controls the rotation angle of the chuck table that rotates on a rotation axis orthogonal to the holding surface, and the notch of the wafer held on the chuck table from the holding hand via the transfer means is in the predetermined direction. The chuck table holding the wafer is rotated so as to face.

  Preferably, the wafer has a chamfered portion on the outer periphery, and the processing means cuts and removes the chamfered portion of the wafer held on the chuck table.

  According to the processing apparatus of the present invention, the wafer is taken out from the cassette by the holding hand and the wafer is imaged, and the orientation of the notch and the center position of the wafer are detected from the captured image of the wafer. Since the rotation angle, the movement distance during wafer conveyance by the conveyance means, and the movement distance of the chuck table can be adjusted, the position detection mechanism that has been conventionally required can be omitted.

  Further, since the outer periphery of the wafer can be reliably and clearly imaged by installing the reflecting material, the direction of the notch and the center position of the wafer can be detected more accurately from the captured image of the wafer.

  Furthermore, since the warped wafer can be suctioned and held in the holding hand to be corrected even if it is partial, the center position can be easily determined by using the captured image of the flat portion.

It is a perspective view of the cutting device concerning the embodiment of the present invention. It is a surface side perspective view of a semiconductor wafer. It is a partial cross section side view explaining the effect | action of the principal part of the cutting device which concerns on this invention embodiment. It is a top view which shows the effect | action of the principal part of a cutting device. It is a top view which shows the relationship between the wafer hold | maintained at the hand, and the predetermined position of a wafer. It is a schematic diagram explaining the adjustment method (control method) of a control means.

  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 2 according to an embodiment of the present invention is shown. Reference numeral 4 denotes a base of the cutting device 2, and a chuck table 6 is disposed on the base 4 so as to be rotatable and reciprocally movable in the X-axis direction by a processing feed mechanism (not shown). The chuck table 6 has a holding surface 6 a that holds the wafer 11 by suction. Reference numeral 8 denotes a bellows that covers the processing feed mechanism.

  A cassette mounting table 10 is disposed on the base 4 so as to be vertically movable (Z-axis direction) by a cassette elevator (elevating means). A cassette 12 containing a plurality of semiconductor wafers 11 as shown in FIG. 3 is placed on the cassette mounting table 10.

  As shown in FIG. 2, a device 15 such as an IC or LSI is formed in each region partitioned by a plurality of division lines (streets) 13 on a surface 11 a of a semiconductor wafer (hereinafter sometimes simply referred to as a wafer) 11. Is formed.

  A notch 21 is formed on the outer periphery of the wafer 11 as a mark indicating the crystal orientation of the wafer. In place of the notch 21, there is also a wafer in which an orientation flat is formed by cutting the outer peripheral portion of the wafer 11 into a large straight line. In the present specification and claims, the notch 21 and the orientation flat are collectively referred to as a notch.

  On the outer periphery of the wafer 11, an arc-shaped chamfer 11e extending from the front surface 11a to the back surface 11b is formed. The wafer 11 formed in this way has a device region 17 in which a plurality of devices 15 are formed, and an outer peripheral surplus region 19 surrounding the device region 17 on its surface.

  Referring again to FIG. 1, a portal-shaped first column 14 is erected on the rear side of the base 4, and the first cutting unit 16 </ b> A and the second cutting unit 16 </ b> B are arranged in the Y-axis direction on the first column 14. It is attached to be movable in the Z-axis direction.

  The first and second cutting units 16A and 16B include a cutting blade 18 attached to the tip of a spindle that is rotationally driven. A gate-shaped second column 20 is erected in an intermediate portion of the base 4. Three guide rails (linear motion shafts) 22, 24, and 26 are fixed to the second column 20.

  Reference numeral 28 denotes a holding hand for unloading the wafer 11 accommodated in the cassette 12 and loading the wafer 11 into the cassette 12, and can reciprocate in the Y-axis direction along the guide rail 22 via the support member 30. It is arranged. A suction hole 28 a is formed in the front end surface of the holding hand 28. The suction hole 28a is connected to the suction means through an electromagnetic valve.

  Reference numeral 32 denotes a first holding means (first holding unit) having a suction holding portion 34, which is disposed along the guide rail 24 so as to reciprocate in the Y-axis direction. Reference numeral 36 denotes a second transport unit (second transport unit) having a suction holding unit 38, which is disposed along the guide rail 26 so as to reciprocate in the Y-axis direction.

  Reference numeral 40 denotes a spinner cleaning unit that spin-cleans and spin-drys the wafer 11 after cutting, and has a rotatable spinner table 42 that holds the wafer. An image pickup means (image pickup unit) 44 is disposed above the transfer path through which the holding hand 28 carries the wafer 11 in and out of the cassette 12. The imaging means 44 includes a camera such as a CCD camera that images the imaging area.

  A reflective material 52 is disposed in the imaging region of the imaging means 44 between the cassette 12 placed on the cassette placing table 10 and the bellows 8. Further, the reflective material 54 is also disposed in a region where the outer periphery of the wafer 11 held on the holding surface of the holding hand 28 is positioned. As the reflectors 52 and 54, for example, a form in which a tape-type reflector is attached can be employed. Alternatively, the reflective material 54 of the holding hand 28 may be mirror-finished on the holding hand 28.

  Next, with reference to FIG. 3 thru | or FIG. 6, the effect | action of the principal part of the cutting device 2 mentioned above is demonstrated. As shown in FIG. 3, a plurality of shelves 12 a are formed on the inner wall of the side wall of the cassette 12 at a predetermined interval, and a plurality of wafers 11 are supported by these shelves 12 a and accommodated in the cassette 12. . The directions of the notches 21 of the wafers 11 accommodated in the cassette 12 are not constant but scattered.

  When the wafer 11 accommodated in the cassette 12 is unloaded from the cassette 12, the holding hand 28 is inserted into the cassette 12 as shown in FIGS. After the wafer 11 is sucked and held on the upper surface, the holding hand 28 is moved at a constant speed in the arrow Y1 direction. In FIG. 4, reference numeral 45 denotes an imaging area of the imaging means 44.

  The wafer 11 is imaged a plurality of times by the imaging means 44 while the wafer 11 is carried out of the cassette 12 by the holding hand 28. For example, as shown in FIGS. 3 (A) and 4 (A), the wafer 11 is imaged once in a state where the wafer 11 is pulled out almost half, and then, as shown in FIGS. 3 (B) and 4 (B), An image is taken once with the wafer 11 completely pulled out of the cassette 12. It is not necessary to stop the movement of the holding hand 28 at the time of imaging, and the wafer 11 held by the holding hand 28 is imaged by the imaging means 44 while the holding hand 28 moves in the Y-axis direction.

  A reflective material 52 is disposed in the imaging region of the imaging means 44 between the cassette 12 placed on the cassette mounting table 10 and the bellows 8, and a reflective material 54 is disposed on the surface of the wafer holding hand 28. Therefore, the image pickup means 44 can surely pick up an image of the outer periphery of the wafer 11 with certainty.

  The imaging means 44 is connected to the control means 46. Although not specifically shown, the control means 46 controls the operation of many other mechanical parts including rotation and movement of the chuck table 6. The control unit 46 synthesizes a plurality of captured images captured by the imaging unit 44 into one captured image, and displays this image on, for example, the display monitor of the cutting device 2.

  Referring to FIG. 5, an example of a captured image displayed on the display monitor is shown. In FIG. 5, a wafer 11 indicated by a two-dot oblique line indicates a wafer at a predetermined position sucked and held by the holding hand 28.

  Thus, in the wafer 11 sucked and held at the predetermined position, the center of the wafer 11 is stopped at the origin position without correcting the moving distance of the holding hand 28 and the first transfer means 32. It is adjusted so that the wafer 11 can be placed on the chuck table 6 in accordance with the center.

  When the image of the wafer 11 picked up by the image pickup unit 44 is indicated by a solid line, the wafer 11 is shifted from a predetermined position and held by the holding hand 28, and the notch 21 is held at a predetermined angle from a predetermined direction (for example, the Y-axis direction). It is held by rotating (for example, 20 °).

  In this case, at least three points on the outer periphery of the wafer 11 are taken from the captured image, and the center C1 of the wafer 11 is detected by the center detection unit 50 of the control means 46 as the intersection of the perpendicular bisectors connecting the two points. Is detected.

  The calculation means 48 of the control means 46 calculates the distance a in the X-axis direction and the distance b in the Y-axis direction between the center C1 of the wafer 11 held by the holding hand 28 and the center C0 of the wafer 11 at a predetermined position. To do.

  Further, the calculation means 48 calculates the angle of the notch 21 of the wafer 11 held by the holding hand 28 from the Y-axis direction. In this embodiment, it is assumed that this angle is 20 °. The calculation means 48 has the above-described center position detection unit 50.

  After the calculation means 48 of the control means 46 thus determines the deviations a and b from the predetermined position of the wafer 11 held by the holding hand 28 and the angle of the notch 21, the control means 46 controls as follows. .

  In other words, the control means 46 is configured so that the center C1 of the wafer 11 is positioned at the center of the chuck table 6 when the first conveyance means 32 conveys the wafer 11 taken and held from the holding hand 28 to the chuck table 6. The moving distance b along the guide rail (linear motion shaft) 22 of the first conveying means 32 and the moving distance a in the machining feed direction of the chuck table 6 are controlled.

  Further, after the center C1 of the wafer 11 is aligned with the center of the chuck table 6 and the wafer 11 is placed on the chuck table 6, the control means 46 moves the chuck table 6 to the arrow A as shown in FIG. The chuck table 6 is rotationally controlled so that the notch 21 of the wafer 11 coincides with the Y-axis direction.

  As a result, the wafer 11 is sucked and held by the chuck table 6 so that the center C1 of the wafer 11 is aligned with the center of the chuck table 6 and the notch 21 faces the Y-axis direction. In this state, the wafer 11 held on the chuck table 6 is cut by the first cutting unit 16A or the second cutting unit 16B.

  In the embodiment described above, the image pickup means 44 is disposed on the carry-out path through which the holding hand 28 carries the wafer 11 out of the cassette 12, and the orientation of the notch 21 and the center C1 of the wafer 11 are detected from the picked-up image of the image pickup means. By doing so, the rotation angle of the chuck table 6, the moving distance during wafer transfer, and the moving distance of the chuck table 6 can be adjusted as appropriate, so that the position detection device that has been conventionally required can be omitted.

  Further, since the reflecting material 52 is arranged in the imaging region of the imaging means 44 between the cassette 12 placed on the cassette placing table 10 and the bellows 8, and the reflecting material 54 is arranged in the holding hand 28, imaging is performed. Sometimes, the outer periphery of the wafer 11 can be reliably imaged, and the orientation of the notch 21 and the center position of the wafer 11 can be reliably detected from the captured image of the wafer 11.

  In the above-described embodiment, the example in which the main part of the present invention is applied to the cutting apparatus has been described. However, the present invention is not limited to this, and laser processing that performs processing by accommodating a single wafer in a cassette. The present invention can be similarly applied to other processing apparatuses such as an apparatus and a grinding apparatus.

2 Cutting device 6 Chuck table 11 Semiconductor wafer 12 Cassette 16A 1st cutting unit 16B 2nd cutting unit 28 Holding hand 32 1st conveyance means 36 2nd conveyance means 44 Imaging means 46 Control means 52, 54 Reflective material

Claims (3)

A chuck table for holding a wafer on a holding surface, a processing means for processing the wafer held on the chuck table, a processing feed means for moving the chuck table in a processing feed direction, and a cassette for storing a plurality of wafers are mounted. A cassette mounting table to be placed, a holding hand for unloading the wafer from the cassette placed on the cassette mounting table, and a transfer means for picking up the wafer from the holding hand and holding the wafer to the chuck table. A processing device comprising:
Imaging means for capturing an image of the wafer carried out from the cassette from above while being held by the holding hand, and obtaining an image of the wafer including the outer periphery;
Calculating means for determining the center position of the wafer held by the holding hand from the coordinates of three or more points on the outer periphery of the wafer of the captured image;
The moving distance of the chuck table in the processing feed direction so that the center of the wafer is positioned at the center of the chuck table when the wafer picked up and held by the transfer means is transferred to the chuck table. And a control means for controlling the moving distance of the conveying means,
A reflective material is disposed in the imaging region for imaging the wafer being unloaded from the cassette by the holding hand,
The reflecting material includes a region having a width exceeding the diameter of the wafer in a direction perpendicular to the unloading direction of the holding hand, and an outer periphery of the wafer held on the holding surface of the holding hand. And a processing device, wherein the processing device is disposed in a region where the head is positioned. The wafer has a notch indicating the crystal orientation on the outer periphery,
The calculating means calculates an angle from a predetermined direction of the notch of the wafer held by the holding hand from the captured image,
The control unit controls a rotation angle of the chuck table that rotates on a rotation axis orthogonal to the holding surface, and the notch of the wafer held on the chuck table from the holding hand via the transfer unit is 2. The processing apparatus according to claim 1, wherein the chuck table holding the wafer is appropriately rotated so as to face a predetermined direction. The wafer has a chamfered portion on the outer periphery,
The processing apparatus according to claim 1, wherein the processing unit includes a cutting blade that cuts and removes the chamfered portion of the wafer held on the chuck table.