JP7051463B2 - Processing method - Google Patents

Description

The present invention relates to a processing method for dividing a workpiece in which a plurality of devices are arranged with a gap on the upper surface of a DAF (Die Attach Film) so as to correspond to each device.

A wafer in which a plurality of devices such as ICs and LSIs are partitioned by a scheduled division line and formed on the surface is divided into individual devices and used for electric devices such as mobile phones and personal computers.

Generally, a bond layer called DAF for bonding to the wiring frame is arranged on the back surface of the device. The DAF is disposed on the back surface of the wafer before dividing the wafer into individual devices, and together with the wafer is divided corresponding to the individual device.

By the way, a groove having a depth corresponding to the finished thickness of the device is formed on the planned division line of the wafer, a protective member is arranged on the front surface of the wafer, the back surface is ground, and the division groove is exposed on the back surface of the wafer. A technique for dividing a wafer into individual devices (see, for example, Patent Document 1), and a condensing point of a laser beam is positioned and irradiated from the back surface of the wafer to the inside corresponding to the planned division line, along the planned division line. In the technique of forming a modified layer and then applying an external force to divide the wafer into individual devices (see, for example, Patent Document 2), the above-mentioned general method is applied to obtain a wafer. It is not possible to dispose the DAF on the back of the wafer before splitting into individual devices and split the DAF with the wafer. Therefore, in such a case, the wafer after being divided into individual devices is arranged on the upper surface of the DAF, and the laser beam is irradiated along the gap formed when the wafer is divided to correspond to each device. (See, for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 2011-11346 Japanese Unexamined Patent Publication No. 2002-192370 Japanese Unexamined Patent Publication No. 2002-118801

According to the technique described in Patent Document 3, a wafer after being divided into individual devices can be arranged on the upper surface of the DAF, and the DAF can be divided corresponding to each device. However, when the wafer after being divided into individual devices is arranged on the upper surface of the DAF, the individual devices are held on the upper surface of the DAF with a meandering gap consisting of the dividing grooves divided along the planned division line. Will be. This meandering gap is imaged and detected by an imaging means used in a normal alignment process or the like, the coordinates of the gap are recorded, and the irradiation position of the laser beam is controlled according to the recorded coordinates to correspond to each device. When cutting the DAF, it is necessary to detect the meandering state of all the gaps of the wafer held in the laser processing device before irradiating the laser beam, so laser processing is started in the laser processing device. There is a problem that it takes a long time and productivity deteriorates.

The present invention has been made in view of the above facts, and the main technical problem thereof is a gap in which a plurality of devices extend in a first direction and a second direction orthogonal to the first direction on the upper surface of the DAF. It is an object of the present invention to provide a processing method for efficiently dividing a DAF according to an individual device for an workpiece arranged with the above.

In order to solve the above-mentioned main technical problem, according to the present invention, a plurality of devices have a gap extending in a first direction and a second direction orthogonal to the first direction on the upper surface of the DAF. It is a processing method of dividing the arranged workpiece into DAFs corresponding to individual devices, and is a first direction and a second direction in which a protective member is arranged on the upper surface and divided into individual devices. A waha preparation step for preparing a waha having a gap extending to the waha, and an integrated waha generation step for arranging a DAF on the back surface of the waha and accommodating the waha through a tape in the opening of the frame to generate an integrated waha. And the peeling step of peeling the protective member from the upper surface of the waha, and the gap extending in the first direction with the first direction of the waha as the X-axis direction is imaged to detect the X-axis and the X-axis direction. The amount of deviation from the center line of the design gap when it is assumed that the X-axis indicating the meandering in the orthogonal Y-axis direction does not meander in the Y-axis direction is detected as a correction value of the Y-axis and recorded in the recording means. The first coordinate recording step and the gap extending in the second direction with the second direction of the wafer as the X-axis direction are imaged to detect the X-axis and meandering in the Y-axis direction orthogonal to the X-axis direction. A second coordinate recording step of detecting the amount of deviation of the design gap with respect to the center line as a correction value of the Y coordinate and recording it in the recording means when it is assumed that the X coordinate does not meander in the Y axis direction. , A holding means for holding the workpiece, a laser beam irradiating means provided with a condenser for irradiating the workpiece held by the holding means with a laser beam, and an X-axis of the condenser for the holding means. A processing feed means for processing and feeding relative to the direction, a correction feeding means for correcting and feeding the concentrator relative to the holding means in the Y-axis direction orthogonal to the X-axis direction, and a region to be machined. A processing preparation step of preparing a laser processing apparatus composed of at least an image pickup means to be detected, and a first coordinate recording step of holding the integrated wafer generated in the integrated wafer generation step in the holding means. And the gap extending in the first direction of the waha is matched in the X-axis direction based on the X-coordinate recorded in advance for each waha in the second coordinate recording step and the correction value of the Y-coordinate in the X-axis, and the X-axis. While processing and feeding in the direction, the meandering in the Y-axis direction is corrected, the gap is irradiated with a laser beam from the concentrator to divide the DAF, and the gap extending in the second direction of the waha is aligned in the X-axis direction. While processing and feeding in the X-axis direction, the meandering in the Y-axis direction is corrected and the light collector is used. A processing method comprising at least a division step of irradiating a gap with a beam of light to divide the DAF is provided.

The machining feed means is an X-axis feed means for machining and feed the holding means in the X-axis direction, and the correction feed means is a Y-axis feed that corrects and feeds the holding means in the Y-axis direction orthogonal to the X-axis direction. It is preferably a means.

The processing method of the present invention includes a waha preparation step of preparing a waha having a gap extending in the first direction and the second direction in which a protective member is arranged on the upper surface and divided into individual devices, and a waha. An integrated waiha generation step of arranging a DAF on the back surface and accommodating the waha through a tape in the opening of the frame to generate an integrated waiha, a peeling step of peeling a protective member from the upper surface of the waha, and the waha With the first direction as the X-axis direction, the gap extending in the first direction is imaged to detect the X-axis, and at the X-axis showing meandering in the Y-axis direction orthogonal to the X-axis direction, with respect to the Y-axis direction. The first coordinate recording step of detecting the amount of deviation of the design gap with respect to the center line as a correction value of the Y coordinate and recording it in the recording means when it is assumed that it does not meander, and the X-axis of the second direction of the wafer. Assuming that the gap extending in the second direction is imaged as the direction, the X coordinate is detected, and the X coordinate shows the meandering in the Y axis direction orthogonal to the X axis direction and does not meander in the Y axis direction. A second coordinate recording step of detecting the amount of deviation of the design gap with respect to the center line as a correction value of the Y coordinate and recording it in the recording means, a holding means for holding the work piece, and holding means held by the holding means. For a laser beam irradiating means provided with a condenser for irradiating a work piece with a laser beam, a processing feeding means for processing and feeding the condenser relative to the holding means in the X-axis direction, and a holding means. Processing to prepare a laser processing apparatus composed of at least a correction feeding means for correcting and feeding the light collector relatively in the Y-axis direction orthogonal to the X-axis direction and an imaging means for detecting a region to be machined. The integrated waiha generated in the preparatory step and the integrated waiha generation step is held in the holding means, and the X coordinates and the X coordinates recorded in advance for each waha in the first coordinate recording step and the second coordinate recording step. Based on the correction value of the Y coordinate in the X coordinate, the gap extending in the first direction of the waha is matched in the X axis direction, and the meandering in the Y axis direction is corrected while feeding in the X axis direction to correct the light collection. The DAF is divided by irradiating the gap with a laser beam from the vessel, and the gap extending in the second direction of the wafer is matched in the X-axis direction and processed and fed in the X-axis direction to correct the meandering in the Y-axis direction. Since it is composed of at least a division process of irradiating a gap with a laser beam from a condenser to divide the DAF, it is possible to efficiently cut the DAF, so the workpiece can be adapted to individual devices. And improve productivity when splitting the DAF be able to.

It is a perspective view which shows the embodiment of the separation groove formation step in the wafer preparation process of this embodiment. It is a perspective view which shows the embodiment of the protection member sticking step in the wafer preparation process of this embodiment. It is a perspective view which shows the embodiment of the wafer division step in the wafer preparation process of this embodiment. It is a perspective view which shows the embodiment of the integrated wafer generation process of this embodiment. It is a perspective view which shows the embodiment of the peeling process of this embodiment. It is a conceptual diagram for demonstrating the embodiment of the 1st coordinate recording process and the 2nd coordinate recording process in the processing method of this embodiment. It is an overall perspective view of the laser processing apparatus configured to carry out the division process of this embodiment. It is a conceptual diagram for demonstrating the embodiment of the division process carried out by the laser processing apparatus shown in FIG. 7.

Hereinafter, the processing method according to the embodiment of the present invention will be described in detail with reference to the attached drawings.

(Wafer preparation process)
In carrying out the processing method of the present embodiment, first, a wafer in which a protective member is arranged on the upper surface and a wafer having a gap extending in the first direction and the second direction divided into individual devices is prepared. Carry out the preparatory process. The wafer preparation step is composed of, for example, a separation groove forming step, a protective member attaching step, and a wafer dividing step. Hereinafter, the explanation will be given step by step.

FIG. 1 shows an enlarged perspective view of a part of the cutting apparatus, and finishes the device 100 along a planned division line formed on the surface Wa side of the wafer W constituting the workpiece of the present embodiment. It shows an embodiment in which a separation groove forming step for forming a separation groove 102 corresponding to a thickness is carried out. The planned division line is formed along the first direction D1 on the wafer W and the second direction D2 orthogonal to the first direction D1. The first direction D1 and the second direction D2 are defined with reference to the notch N formed in the wafer W.

As shown in FIG. 1A, the cutting device includes a spindle unit 10. The spindle unit 10 includes a spindle housing 11 that holds a cutting blade 13 fixed to the tip of a rotary spindle 12. The wafer W before processing is formed to have a predetermined thickness (for example, 700 μm), and is divided into a plurality of regions by a planned division line formed in the first direction D1 and the second direction D2. A device 100 is formed in each of the partitioned areas. The cutting blade 13 rotated at high speed together with the rotary spindle 12 is lowered from the surface Wa side of the waha W sucked and held by the holding table (not shown) of the cutting device with respect to the planned division line, and corresponds to the finished thickness. The cutting is made to a size of 50 μm, and the holding table is relatively moved in the machining feed direction indicated by the arrow X. If a cutting process for forming such a separation groove 102 is performed on one scheduled division line, the holding table is indexed and sent in the direction indicated by the arrow Y, and the adjacent unprocessed planned division line is separated. However, the same cutting process is carried out. If the separation grooves 102 are formed in all of the planned division lines formed in the first direction D1, the holding table is rotated 90 degrees to be formed in the second direction D2 orthogonal to the first direction D1. The same cutting process will be performed on the planned division line. As a result, as shown in FIG. 1 (b) shown as a cross-sectional view taken along the line AA of FIG. 1 (a), a predetermined groove width (at a depth corresponding to the finished thickness of the device 100 along the planned division line). For example, a separation groove 102 of 30 μm) is formed. Note that FIG. 1B emphasizes the separation groove 102 for convenience of explanation, and does not follow the actual dimensional ratio.

The above-mentioned cutting device has a machining feed direction (X-axis direction) along the cutting direction of the cutting blade 13, an indexing feed direction (Y-axis direction) parallel to the machining feed direction and orthogonal to the machining feed direction, and a wafer of the cutting blade 13. It is configured to be controllable according to a program stored in advance for both the cutting direction (Z-axis direction) that moves up and down toward W, and the same separation as above is applied to all on the planned division line on the waha W. The groove 102 is formed. When the separation groove forming step is completed in this way, the wafer W is taken out from the holding table of the cutting device. The separation groove 102 is set to a depth corresponding to the finished thickness of the device, but it does not necessarily have to be exactly the same as the finished thickness of the device, and may be set slightly deeper than the finished thickness.

When the separation groove forming step is completed, as shown in FIG. 2A, a protective tape T1 which is a protective member for protecting the device 100 is attached to the surface Wa side of the wafer W (protection member attachment). The wafer division step of dividing the wafer W (see FIG. 2B) obtained by the attachment step) and the protective member attachment step into individual devices is performed.

The wafer division step will be described with reference to FIG. As shown in FIG. 3A, the wafer W to which the protective tape T1 is attached is positioned on the chuck table 30 provided in the grinding apparatus (the whole description is omitted) with the protective tape T1 side down. Be done. The chuck table 30 is rotatably configured by a motor (not shown), and its upper surface is formed of porous ceramics having fine ventilation holes, and is communicated with a suction means (not shown). The chuck table 30 configured in this way sucks and holds the wafer W placed on the holding surface which is the upper surface of the chuck table 30 by operating the suction means (not shown).

A rotary spindle 31 driven by a servomotor (not shown) is provided above the chuck table 30 of the grinding apparatus, and at the lower end of the rotary spindle 31 set at a position eccentric with respect to the center of the chuck table 30. , The mounter 32 is formed. A grinding wheel 33 provided with a grinding wheel for grinding the wafer W sucked and held on the chuck table 30 is firmly fixed to the mounter 32 by bolts. The grinding device includes a grinding feed means for moving a grinding unit including the rotary spindle 31, a mounter 32, a grinding wheel 33, and a servomotor (not shown) in the grinding feed direction indicated by arrow Z1.

By the above-mentioned grinding feed means, the grinding wheel of the grinding wheel 33 is pressed against the wafer W sucked and held on the chuck table 30. At this time, the chuck table 30 is driven at a rotation speed of 300 rpm in the direction indicated by the arrow R1 and the grinding wheel 33 is driven at a rotation speed of 6000 rpm in the direction indicated by the arrow R2, and is ground and fed downward at a speed of 1 μm / sec indicated by the arrow Z1. .. While measuring the thickness of the wafer W to be ground with a contact type or non-contact type thickness measuring gauge (not shown), the back surface Wb of the wafer W is ground to a desired finished thickness (50 μm). By grinding in this way, as shown in FIG. 3B, the separation groove 102 formed in the above-mentioned separation groove formation step is exposed on the back surface Wb side of the wafer W, and the separation groove 102 is a gap. (Hereinafter referred to as "gap 102"), the wafer W is divided into individual devices 100, and the wafer division step is completed.

The wafer preparation step is completed by carrying out the separation groove forming step, the protective member attaching step, and the wafer dividing step described above.

(Integrated wafer generation process)
After the above-mentioned wafer preparation step is completed, then, as shown in FIG. 4, the DAF is arranged on the back surface Wb of the wafer W, and the wafer W is accommodated and integrated in the opening of the frame F via the tape T2. An integrated wafer generation step for generating a wafer is carried out.

When carrying out the integrated wafer generation step, a frame F for holding the adhesive tape T2 shown in FIG. 4 on the outer periphery is prepared and set in a tape re-covering machine (not shown). Further, a DAF having the same dimensions as the wafer W described above is attached to the center of the tape T2, and an identification member for individually identifying the integrated wafer, for example, a barcode 40, is attached to the vicinity of the outer periphery of the DAF. do. Then, the back surface Wb side of the wafer W is attached to the DAF arranged in the center of the tape T2. At this time, although the wafer W is divided into individual devices 100 through the gap 102, the protective tape T1 is not cut. Therefore, the protective tape T1 holds the entire device 100 without detaching it, and an integrated wafer in which the DAF, the wafer W, and the frame F are integrated is generated, and the integrated wafer generation step is completed. The procedure for generating this integrated wafer is not necessarily limited to attaching the wafer W to the DAF attached to the tape T2, but first attaches the DAF to the back surface Wb of the wafer W. After that, the wafer W may be attached to the center of the tape T2 held on the frame F together with the DAF.

(Peeling process)
When the integrated wafer generation step is completed, as shown in FIG. 5, a peeling step of peeling the protective tape T1 as a protective member from the surface Wa of the wafer W is performed. When the protective tape T1 is peeled off from the wafer W, it is preferable to cure the protective tape T1 by irradiating it with ultraviolet rays or subjecting it to heat treatment to reduce its adhesive strength, depending on the properties of the protective tape T1.

(First coordinate recording process, second coordinate recording process)
The first coordinate recording step and the second coordinate recording step performed after the above-mentioned peeling step is completed will be described with reference to FIG. The first coordinate recording step and the second coordinate recording step in the present embodiment are carried out on the tape changing machine on which the integrated wafer generation step is carried out. As shown in FIG. 6, the tape reattachment machine has an image pickup means 50 for imaging a gap 102 formed between individual devices 100 of the wafer W at a position directly above the wafer W held by the frame F. Is arranged. The holding means (not shown) for holding the wafer W in the tape changing machine is in the X-axis direction, the Y-axis direction, and the image pickup means 50 so that all the gaps 102 formed in the wafer W can be imaged. It is configured to be movable in the direction of rotation. The image pickup information captured by the image pickup means 50 is transmitted to the recording means 52 provided in the tape changing machine.

Here, the meandering of the gap 102 extending in the first direction D1 and the second direction D2 of the wafer W recorded in the recording means 52 will be described. As shown by enlarging a part of the wafer W in the upper part of FIG. 6, the line connecting the centers of the gaps 102 extending in the first direction D1 (indicated by the alternate long and short dash lines L1 to L4 in the enlarged portion) is It meanders in the Y-axis direction at the X coordinates (X1 to Xn) in the X-axis direction. Similarly, the gap 102 extending in the second direction D2 also meanders. By imaging the gap 102 extending in the first direction D1 and the second direction D2 on the wafer W along the X-axis direction, the Y-axis direction in the X coordinate (X1 to Xn) in the X-axis direction is taken. The meandering can be detected as Y coordinates (Y1 to Ym). The value of the Y coordinate that specifies the meandering in the Y-axis direction is such that the line connecting the centers of the gaps 102 extending in the first direction D1 and the second direction D2 on the wayha W is X in the X-axis direction. It is a correction amount (deviation amount) with respect to the center line of the design gap when it is assumed that the coordinates (X1 to Xn) do not meander in the Y-axis direction.

When carrying out the first coordinate recording step and the second coordinate recording step, the image pickup means 50 is positioned on the bar code 40 to take an image, and the captured bar code information is transmitted to the recording means 52. The recording means 52 records the bar code information captured by the image pickup means 50 as information for identifying individual wafers W.

When carrying out the first coordinate recording step, by adjusting the position of the holding means of the tape reattachment machine, the first direction D1 of the wafer W is positioned along the X-axis direction, and the coordinates shown in FIG. 6 are obtained. In, one end of the gap 102 at the position indicated by Y1 is positioned directly below the image pickup means 50. When the image pickup position of the image pickup means 50 is positioned at one end of the gap 102 in this way, the image pickup by the image pickup means 50 is started, and the wafer W is moved in the direction indicated by the arrow X1 to perform the image pickup by the image pickup means 50. The position is moved to the other end of the gap 102. As a result, the image pickup means 50 takes an image of the gap 102 extending in the first direction D1 on the wafer W held by the holding means. The image information of the gap 102 imaged by the image pickup means 50 is sent to the recording means 52, the center of the imaged gap 102 is detected by image processing or the like, and the meandering in the Y-axis direction at the X coordinate is detected as the correction value of the Y coordinate. do. When the meandering of one gap 102 is detected, the wafer W is transferred in the Y-axis direction, the position to be imaged by the image pickup means 50 is positioned in the adjacent gap 102, and the meandering of the gap 102 is detected in the same manner as described above. Such meandering is detected for all the gaps 102 extending in the first direction D1, the meandering in the Y-axis direction in the X coordinate is detected as the correction value of the Y coordinate, and the barcode 40 is used first. It is associated with the acquired barcode information and recorded in the recording means 52 (first coordinate recording step).

When the above-mentioned first coordinate recording step is performed, the wafer W is rotated by 90 degrees so that the second direction D2 orthogonal to the first direction D1 is positioned to coincide with the X-axis direction. If the second direction D2 of the meander W is positioned so as to coincide with the X-axis direction, all the gaps 102 extending in the second direction D2 are imaged in the same manner as in the first coordinate recording step described above. The meandering in the Y-axis direction at the X coordinate is detected as the correction value of the Y coordinate. The information regarding the meandering detected in this way is associated with the barcode information acquired by the barcode 40 and recorded in the recording means 52 as in the first coordinate recording step (second coordinates). Recording process). If there are a plurality of integrated wafers to be prepared, different barcode information is assigned to each integrated wafer, and the first coordinate recording process and the second coordinate recording process are performed for each integrated wafer. It is carried out, associated with each barcode information, and recorded in the recording means 52.

(Processing preparation process)
If the first coordinate recording step and the second coordinate recording step are carried out, the machining preparation step is carried out. FIG. 7 shows an overall perspective view of the laser processing apparatus 1 prepared by the processing preparation step according to the present embodiment. The laser processing apparatus 1 includes a holding means 60 for holding an workpiece, a moving means 70 for moving the holding means 60, and a laser beam irradiating means 90 for irradiating a wafer W held by the holding means 60 with a laser beam. ing.

The laser processing apparatus 1 prepared by the above-mentioned processing preparation step will be described more specifically.

The holding means 60 has a rectangular X-direction movable plate 61 mounted on the base 2 so as to be movable in the X-axis direction indicated by the arrow X in the drawing, and is movable in the Y-axis direction indicated by the arrow Y in the drawing. A rectangular Y-direction movable plate 62 mounted on the X-direction movable plate 61, a cylindrical strut 64 fixed to the upper surface of the Y-direction movable plate 62, and a rectangular strut 64 fixed to the upper end of the strut 64. Includes cover plate 66. The cover plate 66 is provided with a circular chuck table 68 extending upward through an elongated hole formed on the cover plate 66. The chuck table 68 holds the workpiece and is configured to be rotatable by a rotation driving means (not shown). On the upper surface of the chuck table 68, a circular suction chuck 68a formed of a porous material and extending substantially horizontally is arranged. The suction chuck 68a is connected to a suction means (not shown) by a flow path passing through the inside of the support column 64. The chuck table 68 is provided with a clamp 68b for fixing an annular frame F that supports the wafer W.

The moving means 70 is arranged on the stationary base 2, and includes an X-axis feeding means 71 that processes and feeds the holding means 60 in the X-axis direction, and a Y-axis feeding means 72 that compensates and feeds the holding means 60 in the Y-axis direction. , Is equipped. The X-axis feeding means 71 converts the rotational motion of the pulse motor 73 into a linear motion via the ball screw 74 and transmits it to the X-direction movable plate 61, and X along the guide rails 2a and 2a on the base 2. The directional movable plate 61 is moved forward and backward in the X-axis direction. The Y-axis feed means 72 converts the rotational motion of the pulse motor 75 into a linear motion via the ball screw 76 and transmits it to the Y-direction movable plate 62 along the guide rails 61a and 61a on the X-direction movable plate 61. The Y-direction movable plate 62 is moved forward and backward in the Y-axis direction. Although not shown, the X-axis feeding means 71, the Y-axis feeding means 72, and the chuck table 68 are provided with position detecting means, and the position of the chuck table 68 in the X-axis direction and the Y-axis direction. The position and the rotational position in the circumferential direction are accurately detected, transmitted to the control means 80 described later, and based on the instruction signal instructed from the control means 80, the X-axis feed means 71, the Y-axis feed means 72, and (not shown). The rotation driving means of the chuck table 68 is driven, and the chuck table 68 can be positioned at an arbitrary X coordinate position, Y coordinate position, and angle.

A frame body 4 is erected on the side of the moving means 70. The frame body 4 includes a vertical wall portion 4a arranged on the base 2, and a horizontal wall portion 4b extending in the horizontal direction from the upper end portion of the vertical wall portion 4a. The optical system of the laser beam irradiating means 90 is built in the horizontal wall portion 4b of the frame body 4. A condenser 91 that constitutes a part of the laser beam irradiating means 90 is arranged on the lower surface of the tip portion of the horizontal wall portion 4b, and a condenser lens (not shown) that concentrates the laser beam LB is inside the condenser 91. Is built-in.

The control means 80 is configured by a computer and stores a central processing unit (CPU) that executes an operation according to a control program, a read-only memory (ROM) that stores a control program and the like, detected detection values, calculation results, and the like. It is equipped with a readable and writable random access memory (RAM), an input interface, and an output interface.

On the lower surface of the tip portion of the horizontal wall portion 4b, an imaging means 92 for imaging a workpiece is arranged at a position adjacent to the condenser 91 in the X-axis direction. The image pickup means 92 includes an image pickup element (CCD) that takes an image with visible light, and an illumination means (not shown) that irradiates the workpiece with light rays (both are not shown), and is imaged by the image pickup means 92. The image signal is sent to the control means 80.

Based on the above configuration, the control means 80 outputs a control signal for operating the X-axis feed means 71, the Y-axis feed means 72, and the laser beam irradiation means 90 by the control program recorded in the memory.

(Division process)
The laser processing apparatus 1 prepared by the above-mentioned processing preparation step has substantially the same configuration as described above, and the division process carried out by the laser processing apparatus 1 will be described below with reference to FIGS. 6 to 8. ..

The integrated wafer generated in the above-mentioned integrated wafer generation step and subjected to the first coordinate recording step and the second coordinate recording step is held in the holding means 60. More specifically, by placing the wafer W held by the frame F via the tape T2 on the suction chuck 68a of the chuck table 68 and operating the suction means (not shown), the suction chuck 68a of the chuck table 68 is operated. The wafer W is sucked and held. After the wafer W is sucked and held on the chuck table 68, the clamp 68b is operated to grip and fix the frame F.

When the wafer W is fixed to the chuck table 68, the wafer W is imaged from above by the image pickup means 92, and the barcode 40 attached on the tape T2 is imaged. The read information of the barcode 40 is sent to the control means 80. Further, based on the image information captured by the image pickup means 92, the control means 80 executes image processing such as pattern matching to align the condenser 91 of the laser beam irradiation means 90 with the processing region, so-called. Perform alignment.

If the above alignment is performed, the X-axis feed means 71, the Y-axis feed means 72, etc. are operated based on the position information obtained by the alignment, and the gap at the position indicated by Y1 at the coordinates shown in FIG. The condenser 91 is positioned directly above one end of the 102.

As shown in FIG. 8, when one end of the gap 102 is positioned directly under the condenser 91, the laser beam irradiating means 90 is started to operate, and the X-axis feeding means 71 functioning as the machining feeding means is operated. , The chuck table 68 is moved in the direction indicated by the arrow X1 in FIG. 8 to start laser machining. The control means 80 is connected to the recording means 52 that records the meandering about the gap 102 of the wafer W via the computer network, and by referring to the recording means 52, the bar code information represented by the bar code 40 described above is used. Then, the information (X coordinate, Y coordinate) of the meandering of the wafer W currently held in the chuck table 68 is acquired. Based on the information regarding this meandering, a control signal for correcting and feeding the chuck table 68 in the Y-axis direction is transmitted to the pulse motor 75 of the Y-axis feed means 72. By this control signal, while the chuck table 68 is machined and fed in the X-axis direction, correction feed according to the meandering of the gap 102 is performed in the Y-axis direction, and the laser beam LB is irradiated along the center of the gap 102. When the irradiation position of the laser beam LB irradiated through the condenser 91 reaches the other end of the gap 102, the irradiation of the laser beam LB is stopped and the movement of the chuck table 68 is stopped. As a result, the DAF is divided along the center of the gap 102 of the wafer W. If such laser machining is performed on one end to the other end of the gap 102, the chuck table 68 is indexed and fed in the direction indicated by the arrow Y1 by the Y-axis feeding means 72, and the adjacent unmachined gap 102 is fed. However, the same processing as the above-mentioned laser processing is performed. By repeating such processing with respect to the gap 102 arranged along the first direction D1, the laser that divides the DAF corresponding to all the gaps 102 along the first direction D1 of the wafer W. Carry out processing.

If laser machining is performed on all the gaps 102 formed in the first direction D1, the chuck table 68 is rotated 90 degrees to X the gaps 102 extending in the second direction D2 in the wafer W. Match in the axial direction. If the gap 102 extending in the second direction D2 is positioned in the X-axis direction, the same processing as the laser processing performed on the gap 102 extending in the first direction D1 described above can be performed in the second direction. This is also performed for the gap 102 extending in the direction D2. That is, while referring to the recording means 52, the chuck table 68 is machined and fed in the X-axis direction, and is corrected and fed in the Y-axis direction to divide the DAF along the center of the gap 102. By performing this for all the gaps 102 extending in the second direction D2, the division step of dividing the DAF corresponding to all the gaps 102 along the first direction D1 and the second direction D2. Is completed.

The above-mentioned division step can be carried out, for example, under the following processing conditions.
Wavelength of laser beam: 355 nm
Repeat frequency: 50kHz
Average output: 3.0W
Machining feed rate: 250 mm / sec

According to the above-described embodiment, the laser processing is performed on an integrated wafer in which a plurality of devices 100 are arranged on the upper surface of the DAF with a gap 102 extending in the first direction D1 and the second direction D2. The meandering in the Y-axis direction of the gap 102 positioned in the X-axis direction before being carried into the device is recorded in the recording means 52 as a correction value of the Y coordinate with respect to the X coordinate. Then, laser machining is performed by the laser machining device 1 to divide the DAF corresponding to the gap 102 while referring to the coordinate information indicating the correction value recorded in the recording means 52. Therefore, it is possible to save the trouble of detecting the coordinates indicating the meandering of the gap 102 extending in the X-axis direction in the laser processing apparatus 1, and the production efficiency is good.

In the present embodiment, information for individually identifying the wafer W is bar-coded and attached to the tape T2 held by the frame F, but the present invention is not limited to this, and for example, the outer periphery on which the device on the wafer W is not formed is not formed. Information for identifying the wafer W may be formed in the region and imaged. Further, the information for identifying the wafer W does not necessarily have to be bar-coded, and may be a numerical value, a symbol, an alphabet, or the like.

In the present embodiment, in the wafer preparation step, a separation groove is prepared in order to prepare a wafer W in which a plurality of devices are arranged with a gap 102 extending in the first direction D1 and the second direction D2. Although the forming step, the protective member attaching step, and the wafer dividing step have been carried out, the method for carrying out the wafer preparation step is not limited to this, and for example, the back surface Wb of the wafer W formed to the finished thickness in advance is not limited to this. Therefore, a condensing point of a laser beam having a wavelength that is transparent to the wafer W is positioned and irradiated inside corresponding to the planned division line to form a modified layer along the planned division line, and then an external force is applied. Then, the wafer W may be divided into individual devices to form a gap.

1: Laser processing device 2: Stationary base 4: Frame body 10: Spindle unit 13: Cutting blade 30: Chuck table 31: Rotating spindle 33: Grinding wheel 40: Bar code 50: Imaging means 52: Recording means 60: Holding means 68: Chuck table 70: Moving means 71: X-axis feeding means (machining feeding means)
72: Y-axis feed means (correction feed means)
80: Control means 90: Laser beam irradiation means 91: Condenser 92: Imaging means 100: Device 102: Gap (separation groove)
W: Wafer T1: Protective tape (protective member)
T2: Tape

Claims (2)

A work piece in which a plurality of devices are arranged on the upper surface of the DAF with a gap extending in a first direction and a second direction orthogonal to the first direction corresponds to each device. It is a processing method that divides the DAF.
A wafer preparation step in which a protective member is arranged on the upper surface and a wafer having a gap extending in the first direction and the second direction divided into individual devices is prepared.
An integrated wafer generation process in which a DAF is placed on the back surface of the wafer and the wafer is accommodated in the opening of the frame via tape to generate an integrated wafer.
A peeling process that peels off the protective member from the upper surface of the wafer,
With the first direction of the wafer as the X-axis direction, the gap extending in the first direction is imaged to detect the X-coordinate, and the Y-axis at the X-coordinate showing meandering in the Y-axis direction orthogonal to the X-axis direction. The first coordinate recording step of detecting the amount of deviation of the design gap with respect to the center line as a correction value of the Y coordinate and recording it in the recording means when it is assumed that it does not meander in the direction .
With the second direction of the waha as the X-axis direction, the gap extending in the second direction is imaged to detect the X-coordinate, and the Y-axis at the X-coordinate showing meandering in the Y-axis direction orthogonal to the X-axis direction. A second coordinate recording process that detects the amount of deviation of the design gap with respect to the center line as a correction value of the Y coordinate and records it in the recording means when it is assumed that it does not meander in the direction .
A holding means for holding the work piece, a laser beam irradiation means provided with a light collector for irradiating the work piece held by the holding means with a laser beam, and an X-axis direction of the light collector with respect to the holding means. The processing feed means for relatively processing and feeding, the correction feeding means for correcting and feeding the concentrator relative to the holding means in the Y-axis direction orthogonal to the X-axis direction, and the region to be machined are detected. Imaging means to be performed, and a processing preparation process for preparing a laser processing apparatus composed of at least
The integrated wafer generated in the integrated wafer generation step is held in the holding means, and the X coordinates and the X coordinates recorded in advance for each wafer in the first coordinate recording step and the second coordinate recording step are used. Based on the correction value of the Y coordinate, the gap extending in the first direction of the wafer is matched in the X-axis direction, and while processing and feeding in the X-axis direction, the meandering in the Y-axis direction is corrected and the laser beam is emitted from the condenser. The DAF is divided by irradiating the gap, the gap extending in the second direction of the wafer is matched in the X-axis direction, and the meandering in the Y-axis direction is corrected while being processed and fed in the X-axis direction from the condenser. A processing method consisting of at least a division step of irradiating a gap with a laser beam to divide the DAF. The machining feed means is an X-axis feed means for machining and feed the holding means in the X-axis direction.
The processing method according to claim 1, wherein the correction feed means is a Y-axis feed means for correcting and feeding the holding means in the Y-axis direction orthogonal to the X-axis direction.

Images