JP2022109746A - Wafer cutting method - Google Patents

Abstract

To provide a wafer cutting method capable of reducing adhesion of cutting scraps accompanying drying in kerf check.SOLUTION: A wafer cutting method for cutting a wafer 100 having a device region 107 in which a plurality of devices 103 are formed and an outer peripheral surplus region 108 surrounding the device region 107 along a dividing line 102 dividing the plurality of devices 103 includes a holding step of holding the wafer 100 on a holding table 10, a cutting step of cutting the wafer 100 held by the holding table 10 along the dividing line 102 with a cutting blade 21 to form a cutting groove while supplying cutting water to a processing point, and a kerf check step of imaging the device region 107 to which the air is injected to check at least the position of the cutting groove after removing cutting water adhering to the surface 101 by injecting air into the device region 107 near the outer peripheral surplus region 108.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wafer cutting method.

In a cutting method for cutting a wafer, it is known to perform an operation called a kerf check during cutting in order to confirm the position and quality of cut grooves. The kerf check captures an image of the cutting groove, measures chipping, measures the width of the cutting groove, measures and corrects the deviation (cutting position deviation) between the machining position recognized by the microscope and the position where the cutting groove is actually formed. hairline alignment, etc. (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Application Publication No. 2001-298000 JP 2008-258496 A

When performing a kerf check, it is necessary to remove water droplets from the imaging area in order to take an image. Air is jetted from a nozzle installed on the bottom surface of the imaging unit to remove the water droplets before imaging. However, there is a problem that if the cutting chips are dried with adhering chips, they cannot be removed even after washing.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object thereof is to provide a wafer cutting method capable of reducing adhesion of chips due to drying during a kerf check.

In order to solve the above-described problems and achieve the object, the wafer cutting method of the present invention uses a processing apparatus to cut a wafer having a device region in which a plurality of devices are formed and an outer peripheral surplus region surrounding the device region. 1. A wafer cutting method for cutting along a dividing line that partitions the plurality of devices, comprising: a holding step of holding the wafer on a holding table; a cutting step of cutting the cut wafer along the dividing line with a cutting blade to form cutting grooves; and removing cutting water adhering to the surface by injecting air into the device region near the peripheral surplus region. and a kerf check step of confirming at least the position of the cutting groove by imaging the device region where the air is injected after the cutting.

The processing apparatus has a second holding table that is installed adjacent to the holding table and holds a dummy wafer, and the method for cutting the wafer comprises forming a second cutting groove in the dummy wafer with the cutting blade. An image pickup unit having a hairline which is a line to be cut by the cutting blade and a deviation between the hairline and the second cutting groove are measured to correct the positional relationship between the image pickup unit and the cutting blade. further comprising a hairline alignment step, during the hairline alignment step, further performing a cleaning step of supplying cleaning water to the wafer held on the holding table to clean the surface of the wafer; may be performed after performing the kerf check step.

The wafer cutting method includes a target registration step of registering an arbitrary pattern of the device as a target for detecting the planned division line, and a distance registration step of measuring and registering the distance from the target to the planned division line. and the kerf check step ejects air to a position away from the cutting groove to remove cutting water adhering to the surface, and then images the position where the air is ejected. However, if the target does not exist in the captured image, there may be a target check step of detecting that the cutting position is misaligned.

The present invention can reduce adhesion of shavings due to drying during kerf check.

FIG. 1 is a perspective view showing a configuration example of a processing apparatus that implements a wafer cutting method according to a first embodiment. 2 is a perspective view showing a processing unit of the processing apparatus of FIG. 1. FIG. 3 is a cross-sectional view showing an imaging unit and an air injection unit of the processing apparatus of FIG. 1. FIG. FIG. 4 is a flow chart showing an example of the processing procedure of the wafer cutting method according to the first embodiment. FIG. 5 is a perspective view for explaining check areas in the wafer cutting method according to the first embodiment. FIG. 6 is a top view showing a main part of a processing apparatus that implements the wafer cutting method according to the second embodiment. FIG. 7 is a flow chart showing an example of the processing procedure of the wafer cutting method according to the second embodiment. FIG. 8 is a diagram for explaining the hairline alignment step of FIG. FIG. 9 is a top view showing a main part of a wafer for which the wafer cutting method according to the third embodiment is performed. FIG. 10 is a flow chart showing an example of the processing procedure of the wafer cutting method according to the third embodiment.

A form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions, or changes in configuration can be made without departing from the gist of the present invention.

[Embodiment 1]
A wafer cutting method according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration example of a processing apparatus 1 that implements a wafer cutting method according to a first embodiment. 2 is a perspective view showing the processing unit 20 of the processing apparatus 1 of FIG. 1. FIG. FIG. 3 is a cross-sectional view showing the imaging unit 30 and the air injection unit 40 of the processing apparatus 1 of FIG. 1. As shown in FIG. As shown in FIG. 1, the processing apparatus 1 includes a holding table 10, a second holding table 15, a processing unit 20, an imaging unit 30, an air injection unit 40, an X-axis moving unit 51, a Y-axis A moving unit 52 , a Z-axis moving unit 53 , a control unit 60 and a washing water supply unit 70 are provided.

The wafer 100 to be processed by the wafer cutting method according to the first embodiment, that is, the wafer 100 to be processed by the processing apparatus 1 is made of, for example, silicon, sapphire, silicon carbide (SiC), gallium arsenide, glass, or the like. disk-shaped semiconductor wafers, optical device wafers, and the like. As shown in FIG. 1, the wafer 100 has a flat surface 101, a device region 107, and a peripheral surplus region 108. As shown in FIG. The device region 107 is a region in which a plurality of chip-sized devices 103 are formed in a region partitioned by a plurality of planned dividing lines 102 in a grid pattern. The peripheral surplus region 108 surrounds the device region 107 over the entire periphery thereof and is a region in which the device 103 is not formed. In the first embodiment, the wafer 100 has an adhesive tape 105 adhered to the back surface 104 on the back side of the front surface 101, and an annular frame 106 is attached to the outer edge of the adhesive tape 105, but the present invention is not limited to this.

The holding table 10 includes a disk-shaped frame body having a recess and a disk-shaped suction portion fitted in the recess. The suction portion of the holding table 10 is formed of porous ceramic or the like having a large number of porous holes, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown). The upper surface of the suction portion of the holding table 10 is a holding surface 11 on which the wafer 100 is placed and which sucks and holds the placed wafer 100 . In Embodiment 1, the wafer 100 is placed on the holding surface 11 with the surface 101 facing upward, and the holding surface 11 holds the placed wafer 100 by suction from the rear surface 104 side via the adhesive tape 105 . The holding surface 11 and the upper surface of the frame of the holding table 10 are arranged on the same plane and formed along the XY plane parallel to the horizontal plane. As shown in FIG. 1, the holding table 10 is provided movably along the X-axis direction parallel to the horizontal direction by the X-axis moving unit 51 . The holding table 10 is rotatable about a Z-axis parallel to the vertical direction and orthogonal to the XY plane by a rotation drive source (not shown).

The processing unit 20 includes a cutting blade 21, a spindle 22, a spindle housing 23, a mount 24, a blade cover 25, a cutting water supply section 26, and a cutting water supply source 27, as shown in FIG. . As shown in FIG. 1, the processing unit 20 is provided movably along a Y-axis direction parallel to the horizontal direction and orthogonal to the X-axis direction by a Y-axis movement unit 52, and by a Z-axis movement unit 53, It is provided movably along the Z-axis direction.

The cutting blade 21 is fixed to the tip of the spindle 22 via a mount 24, and rotates around an axis parallel to the Y-axis direction as the spindle 22 rotates. The spindle 22 is rotatably supported by the spindle housing 23 about an axis parallel to the Y-axis direction and housed in the spindle housing 23 with its tip exposed from the spindle housing 23 . The blade cover 25 is attached to the front side of the spindle housing 23 and covers at least part of the front side of the cutting blade 21 and the spindle 22 . The blade cover 25 has a plurality of water channels formed therein.

The cutting water supply part 26 is provided in communication with the lower end side of the water channel inside the blade cover 25 . The cutting water supply source 27 is provided in communication with the upper end side of the water channel inside the blade cover 25 . The cutting water supply unit 26 supplies the cutting water 29 (see FIG. 3) supplied from the cutting water supply source 27 through the water channel inside the blade cover 25 to the machining point. Here, the processing point refers to a region of the wafer 100 that is cut by the rotating cutting blade 21 , and is a region where the rotating cutting blade 21 and the wafer 100 are in contact. The cutting water 29 is, for example, pure water in the first embodiment.

The imaging unit 30 includes an imaging device that images the surface 201 including the dividing lines 202 of the wafer 100 before processing and the cutting grooves 110 formed in the wafer 100 after processing. The imaging device is, for example, a CCD (Charge-Coupled Device) imaging device or a CMOS (Complementary Metal Oxide Semiconductor) imaging device. In the first embodiment, the imaging unit 30 is fixed below the spindle housing 23 so as to move integrally with the processing unit 20 .

The imaging unit 30 captures an image of the wafer 100 before processing held on the holding table 10, and obtains an image for performing alignment for aligning the wafer 100 and the cutting blade 21 of the processing unit 20. The image is output to control unit 60 . In addition, the imaging unit 30 captures an image of the wafer 100 during or after processing held on the holding table 10 to obtain an image for performing a so-called kerf check for automatically confirming the quality of the cut groove 110, The obtained image is output to the control unit 60 .

The imaging unit 30 includes an objective lens 31 and a shutter 32, as shown in FIG. The objective lens 31 faces the front surface 101 side of the wafer 100 held on the holding table 10 and collects the light from the front surface 101 side of the wafer 100 . The shutter 32 selectively opens and closes between the objective lens 31 and the surface 101 of the wafer 100 held on the holding table 10 . The shutter 32 prevents the objective lens 31 from contacting the surface 101 of the wafer 100 held on the holding table 10 during cutting by the processing unit 20 while cutting water 29 is being supplied or during air injection by the air injection unit 40 . The gap is closed to prevent the cutting water 29 from scattering toward the objective lens 31 side, and the gap between the objective lens 31 and the surface 101 of the wafer 100 held on the holding table 10 is opened during imaging by the imaging device. do.

The air injection unit 40 includes an air injection nozzle 41, an air supply source 42, and a nozzle adjuster 43, as shown in FIG. The air injection unit 40 is fixed to the side of the imaging unit 30 and moves integrally with the processing unit 20 in the same manner as the imaging unit 30 .

The air injection nozzle 41 is provided so that its tip end faces an imaging region 120 on the surface 101 side of the wafer 100 held on the holding table 10 . Here, the imaging area 120 is an area that is imaged by the imaging device of the imaging unit 30 on the surface 101 side of the wafer 100 held on the holding table 10 . The air supply source 42 is provided in communication with the base end side of the air injection nozzle 41 . The nozzle adjustment unit 43 is provided on the side of the air injection nozzle 41 and adjusts the injection direction of the air 49 by the air injection nozzle 41 by rotating the air injection nozzle 41 around the Z-axis. The air injection unit 40 removes the cutting water 29 adhering to the imaging area 120 by injecting the air 49 supplied from the air supply source 42 toward the imaging area 120 through the air injection nozzle 41 . The air 49 supplied from the air supply source 42 and injected from the air injection nozzle 41 is, for example, compressed air in the first embodiment.

The control unit 60 controls the operation of each component of the processing apparatus 1 to cause the processing apparatus 1 to perform cutting processing of the wafer 100 . The control unit 60 includes a computer system in the first embodiment. The computer system including the control unit 60 includes an arithmetic processing unit having a microprocessor such as a CPU (Central Processing Unit), a storage device having a memory such as ROM (Read Only Memory) or RAM (Random Access Memory), and an input/output interface device. The arithmetic processing device of the control unit 60 performs arithmetic processing according to a computer program stored in the storage device of the control unit 60, and outputs control signals for controlling the processing device 1 to the input/output interface device of the control unit 60. to each component of the processing apparatus 1 via the .

The control unit 60 performs a kerf check based on the captured image of the cut groove 110 . Here, specifically, the kerf check is performed based on an image of the cut groove 110, for the cut groove 110, cut position deviation (off-center), kerf width, chipping width from the kerf center, width from the kerf edge The quality of the cutting groove 110 is confirmed by detecting one of the check items such as the Max chipping width and judging whether or not the detected value is acceptable. Note that the cut position deviation (off-center) is the value of the deviation in the width direction of the kerf center, which is the center line representing the center position of the cutting groove 110 in the width direction, with respect to the center line of the dividing line 102 . The kerf width is the distance (interval) between both ends of the cutting groove 110 in the area checked by the kerf check. The chipping width from the kerf center is the distance between the edge of the largest chipping in the width direction and the center of the cut groove 110 in the width direction in the area checked by the kerf check. The Max chipping width from the kerf edge is the distance between the edge of the maximum chipping in the width direction and the edge of the cutting groove 110 in the area checked by the kerf check. The pass/fail judgment is to pass if the detected value is within the range of allowable values preset for each check item, and to fail (result error) if it is outside the range of allowable values.

The processing apparatus 1 further includes a cassette mounting table 81, a cleaning unit 82, and a transport unit 83, as shown in FIG. The cassette mounting table 81 is a mounting table for mounting a cassette 85, which is a container for containing a plurality of wafers 100, and moves the mounted cassette 85 up and down in the Z-axis direction. The cleaning unit 82 cleans the wafer 100 after cutting and removes foreign matter such as shavings adhering to the wafer 100 . The transport unit 83 transports the wafer 100 between the holding table 10 , cleaning unit 82 and cassette 85 .

The processing device 1 may further include a display unit (not shown). The display unit displays a screen for setting conditions for cutting processing of the processing apparatus 1, an image for performing alignment, an image for performing kerf check, inspection results of cut groove 110 by kerf check, and the like. The display unit is configured by a liquid crystal display device or the like. The display unit is provided with an input unit used when the operator inputs information about the cutting conditions of the processing apparatus 1 and the like. The input unit provided in the display unit is composed of at least one of a touch panel provided in the display unit and a keyboard or the like.

Although the second holding table 15 and the cleaning water supply unit 70 are shown in FIG. 1, they are not involved in the processing of the wafer cutting method according to the first embodiment described below. 2 describes its function and operation.

Next, in this specification, the processing of the wafer cutting method according to the first embodiment will be described with reference to the drawings. FIG. 4 is a flow chart showing an example of the processing procedure of the wafer cutting method according to the first embodiment. FIG. 5 is a perspective view for explaining the check area 109 of the wafer cutting method according to the first embodiment. The wafer cutting method according to the first embodiment comprises a holding step 1001, a cutting step 1002, and a kerf check step 1003, as shown in FIG.

A holding step 1001 is a step of holding the wafer 100 on the holding table 10 . In a holding step 1001 , the control unit 60 causes the holding table 10 to hold the wafer 100 placed on the holding surface 11 with the front surface 101 facing upward, from the rear surface 104 side through the adhesive tape 105 , on the holding surface 11 . Hold suction. After carrying out the holding step 1001 , the control unit 60 carries out alignment using the image captured by the imaging unit 30 to determine the positions of the wafer 100 on the holding surface 11 of the holding table 10 and the cutting blade 21 of the processing unit 20 . Align.

The cutting step 1002 is a step of cutting the wafer 100 held on the holding table 10 with the cutting blade 21 along the dividing line 102 to form the cutting groove 110 while supplying the cutting water 29 to the processing point. In the cutting step 1002, the control unit 60 controls the processing unit 20 to supply the cutting water 29 to the processing point from the cutting water supply unit 26, and rotate the cutting blade 21 by the spindle 22 while moving the cutting blade 21 along the X axis. The rotating cutting blade 21 is caused to cut into the wafer 100 on the holding table 10 by the unit 51 , the Y-axis moving unit 52 and the Z-axis moving unit 53 , so that the wafer 100 is relatively cut along the dividing line 102 . By moving along the cutting blade 21 during rotation, the wafer 100 is cut along the dividing line 102 to form a cutting groove 110 along the dividing line 102 .

In the kerf check step 1003, after the air 49 is jetted to the device region 107 near the outer peripheral surplus region 108 to remove the cutting water 29 adhering to the surface 101, the device region 107 to which the air 49 is jetted is imaged to at least This is the step of confirming the position of the cut groove 110 . A kerf check step 1003 is performed after at least one cut groove 110 is formed by the cutting step 1002 . In the first embodiment, the kerf check step 1003 may be performed after the cut grooves 110 are formed along some of the planned division lines 102 by the cutting step 1002, and all of the planned division lines 102 are cut by the cutting step 1002. It may be performed after the cut groove 110 is formed along.

The region within the device region 107 near the outer peripheral surplus region 108 that is the subject of cutting water 29 removal and imaging in the kerf check step 1003 includes a portion of the surface 101 of the device 103 adjacent to the outer peripheral surplus region 108. , is a region having an area equivalent to that of the imaging region 120. In the first embodiment, for example, as shown in FIG. Therefore, in the kerf check step 1003 , first, the control unit 60 moves the imaging unit 30 and the air injection unit 40 using the Y-axis moving unit 52 and the Z-axis moving unit 53 to move the imaging area 120 of the imaging unit 30 . Move to check area 109 .

In kerf check step 1003, after moving imaging area 120 of imaging unit 30 to check area 109, drying step 1011, imaging step 1012, and inspection step 1013 are sequentially performed as shown in FIG. In the drying step 1011 , the control unit 60 controls the air injection unit 40 so that the air injection nozzle 41 injects the air 49 supplied from the air supply source 42 toward the check area 109 . remove the cutting water 29 adhering to the In the image capturing step 1012 , the control unit 60 uses the image capturing unit 30 to image the check area 109 from which the cutting water 29 has been removed by jetting the air 49 in the drying step 1011 . In the inspection step 1013, the control unit 60 performs a kerf check on the cutting grooves 110 formed along the planned division lines 102 in the check area 109 based on the image of the check area 109 captured in the image capturing step 1012. , to check the position of the cutting groove 110 and to check the quality of the cutting groove 110 of the cutting groove 110;

In the wafer cutting method according to the first embodiment, the control unit 60 determines whether or not it is possible to continue the cutting processing by the processing apparatus 1 based on the inspection result of the inspection step 1013 (step 1004). In step 1004, when all the inspection results of inspection step 1013 are acceptable, the control unit 60 determines that the cutting process by the processing apparatus 1 can be continued (Yes in step 1004), and the process is started. Proceed to step 1005 in FIG. In step 1004, if even one of the inspection results in inspection step 1013 fails, the control unit 60 determines that the cutting process by the processing apparatus 1 can be continued (No in step 1004), The cutting processing by the processing device 1 is stopped.

In the wafer cutting method according to the first embodiment, if Yes in step 1004, the control unit 60 determines whether or not the cutting process has been completed along all the planned division lines 102 on which the cutting process is to be performed. Determine (step 1005 in FIG. 4). In step 1005, if all the scheduled cutting processes have not been completed (No in step 1005 in FIG. 4), the control unit 60 restarts the cutting of the wafer 100 by the processing apparatus 1 from the continuation. The cutting step 1002 and kerf check step 1003 are performed again. At step 1005, the control unit 60 terminates the process when all scheduled cutting processes have been completed (Yes at step 1005 in FIG. 4).

In the wafer cutting method according to the first embodiment having the configuration described above, in the kerf check step 1003, the cutting water 29 is removed by jetting the air 49 and the image is captured in the device region 107 near the outer peripheral surplus region 108. Since the drying is performed in the area, the area of the device area 107 that is dried when the area is dried by jetting the air 49 can be kept smaller than when the drying is performed in the center of the wafer 100 . As a result, the wafer cutting method according to the first embodiment has the effect of being able to reduce the adherence of cutting debris that accompanies drying during the kerf check.

[Embodiment 2]
A wafer cutting method according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 6 is a top view showing a main part of the processing apparatus 1 that implements the wafer cutting method according to the second embodiment. FIG. 7 is a flow chart showing an example of the processing procedure of the wafer cutting method according to the second embodiment. FIG. 8 is a diagram for explaining the hairline alignment step 1021 in FIG. In FIGS. 6, 7 and 8, the same reference numerals are given to the same parts as in the first embodiment, and the description thereof is omitted.

As shown in FIG. 6, the second holding table 15 is provided off the moving path of the holding table 10 along the X-axis direction and directly below the moving path of the spindle 22 of the processing unit 20 along the Y-axis direction. It is The second holding table 15 has a configuration similar to that of the holding table 10 , and the area of the holding surface 16 is smaller than that of the holding surface 11 of the holding table 10 . As shown in FIG. 6, the holding surface 16 of the second holding table 15, on which the dummy wafer 150 is placed, holds the placed dummy wafer 150 by suction.

The dummy wafer 150 is made of the same material as the wafer 100 and formed in a plate shape having a smaller area perpendicular to the thickness direction than the wafer 100, and the planned dividing line 102 and the device 103 are not formed. Dummy wafer 150 is, for example, a small piece of silicon. The dummy wafer 150 is cut by the cutting blade 21 to form the second cut grooves 160 (see FIG. 8).

The processing apparatus 1 moves the cutting blade 21 directly above the dummy wafer 150 on the holding surface 16 of the second holding table 15 by moving the processing unit 20 along the Y-axis direction using the Y-axis moving unit 52. Furthermore, while rotating the cutting blade 21, the Z-axis movement unit 53 moves the machining unit 20 downward along the Z-axis direction, thereby allowing the cutting blade 21 to move the dummy on the second holding table 15. Wafer 150 may be cut to form a second cut groove 160 .

In the processing apparatus 1 , the imaging unit 30 and the air injection unit 40 are fixed below the spindle housing 23 so as to move integrally with the processing unit 20 . Therefore, the processing apparatus 1 uses the Y-axis moving unit 52 and the Z-axis moving unit 53 to form an imaging area 120 on the dummy wafer 150, which is imaged by the imaging unit 30 and ejects the air 49 by the air ejection unit 40. can be moved to a region including the second cutting groove 160 that has been cut.

Alternatively, the second holding table 15 may have a drive mechanism that moves in the X-axis direction, and the imaging unit 30 and the air injection unit 40 may be installed adjacent to the processing unit 20 in the X-axis direction. Alternatively, the second holding table 15 is fixed to the holding table 10, and by driving the holding table 10 in the X-axis direction, the second cutting groove 160 is formed in the dummy wafer 150, and the imaging unit 30 and the air injection unit are formed. 40 may be installed adjacent to the processing unit 20 in the X direction.

As shown in FIG. 6, the cleaning water supply unit 70 is provided along the Y-axis direction so as to straddle above the moving path of the holding table 10 along the X-axis direction. The cleaning water supply unit 70 includes a cleaning water supply section 71 and a cleaning water supply source 72 . The cleaning water supply source 72 is provided in communication with the cleaning water supply section 71 . The cleaning water supply unit 70 supplies cleaning water supplied from a cleaning water supply source 72 to the wafer 100 held by the holding table 10 that is moving under the cleaning water supply unit 71 extending in the Y-axis direction. The surface 101 of the wafer 100 is cleaned by being supplied by the supply unit 71 . The cleaning water supplied from the cleaning water supply source 72 and supplied from the cleaning water supply unit 71 is, for example, pure water in the first embodiment.

Next, in this specification, the processing of the wafer cutting method according to the second embodiment will be described with reference to the drawings. As shown in FIG. 7, the wafer cutting method according to the second embodiment further includes a hairline alignment step 1021 in the first embodiment, further performs a cleaning step 1022 during the hairline alignment step 1021, and performs a cleaning step 1022. It is modified so that the kerf check step 1003 is performed after the step 1022 is performed.

In the hairline aligning step 1021, the second cutting groove 160 is formed in the dummy wafer 150 by the cutting blade 21, and the hairline 210 (see FIG. 8), which is the scheduled cutting line of the cutting blade 21, is formed in the imaging screen 200 (see FIG. 8). and the second cutting groove 160 to correct the positional relationship between the imaging unit 30 and the cutting blade 21 .

In the hairline alignment step 1021 , first, the control unit 60 rotates the cutting blade 21 aligned with the dummy wafer 150 on the second holding table 15 (for example, the center of the dummy wafer 150 ). 21 is moved relative to the dummy wafer 150 along the cutting feed direction, and the cutting blade 21 cuts the dummy wafer 150 by a predetermined amount to cut the dummy wafer 150 to form the second cutting grooves 160. , and then the cutting blade 21 is lifted and retracted from the dummy wafer 150 to perform so-called chopper cutting. In the hairline alignment step 1021, the control unit 60 next determines the position where the cutting blade 21 forms the second cutting groove 160 based on the preset positional relationship between the imaging unit 30 and the cutting blade 21. The imaging unit 30 is moved to a position, and the imaging screen 200 is obtained by imaging the dummy wafer 150 with the moved imaging unit 30 .

In the hairline matching step 1021, next, as shown in FIG. A hairline shift 170, which is the shift between the groove 160 and the kerf center, is measured. In the hairline alignment step 1021 , based on the measured hairline deviation 170 , the positional relationship between the imaging unit 30 and the cutting blade 21 is corrected in the direction of eliminating the hairline deviation 170 . When the second holding table 15 moves in the X-axis direction, the hairline alignment step 1021 moves the second holding table 15 along the X-axis while the cutting blade 21 is lowered to a depth at which the dummy wafer 150 is not completely cut. The second cutting groove 160 may be formed from one end to the other end of the dummy wafer 150 by moving in the direction.

The cleaning step 1022 is a step of supplying cleaning water to the wafer 100 held on the holding table 10 to clean the surface 101 of the wafer 100 . In the cleaning step 1022, the control unit 60 causes the holding table 10 to move by the X-axis moving unit 51 to pass under the cleaning water supply section 71 extending in the Y-axis direction. Cleaning water is supplied to the wafer 100 to clean the surface 101 of the wafer 100 . Alternatively, the cleaning water supply unit 71 may move in the X-axis direction to clean the surface 101 of the wafer 100 .

When the spindle 22 on which the cutting blade 21 is mounted expands due to the heat generated during cutting, or the cutting blade 21 falls down due to the cutting load, the imaging unit 30 recognizes a hairline 210, which is a scheduled cutting line, and the scheduled cutting line. Therefore, the wafer cutting method according to the second embodiment corrects the hairline deviation 170 in addition to the first embodiment. Further perform hairline alignment for In the wafer cutting method according to the second embodiment, hairline alignment is performed by forming second cutting grooves 160 on the dummy wafer 150 held on the second holding table 15, and cleaning is performed during the hairline alignment. The water supply unit 70 supplies washing water to the wafer 100 held on the holding table 10 to wash it. For this reason, the wafer cutting method according to the second embodiment has, in addition to the effects of the first embodiment, the effect of reducing the adhesion of cutting debris caused by drying on the wafer 100 during hairline alignment. Effective. In addition, in the wafer cutting method according to the second embodiment, by cleaning the wafer 100 during hairline alignment, cutting waste can be removed, so that the adhesion of cutting waste to the wafer 100 can be further prevented. can be done. In addition, in the wafer cutting method according to the second embodiment, even when the kerf check step 1003 is performed after the cleaning step 1022, the wafer 100 is cut when the cutting groove 110 or the target 180 (see FIG. 9 of the third embodiment) is imaged. Even if the surface 101 of is dried, foreign matter is less likely to adhere because cutting waste has been removed by the cleaning step 1022 .

[Embodiment 3]
A wafer cutting method according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 9 is a top view showing a main part of a wafer 100 for carrying out the wafer cutting method according to the third embodiment. FIG. 10 is a flow chart showing an example of the processing procedure of the wafer cutting method according to the third embodiment. In FIGS. 9 and 10, the same parts as in Embodiments 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

Each device 103 of the wafer 100 is formed with a target 180 as shown in FIG. 9 in the third embodiment. The target 180 has a characteristic shape and serves as a key pattern of planar shape and color that can be detected in the image captured by the imaging unit 30 . The target 180 is formed at a predetermined distance from each planned division line 102 surrounding the device 103 on which the target 180 is formed, and serves as a mark for detecting the planned division line 102 . In the example shown in FIG. 9, the target 180 is located at a position separated by a distance 181 in the +Y direction from the planned division line 102 along the X-axis direction and at a distance in the +X direction from the planned division line 102 along the Y-axis direction. It is formed at a position separated by 182. In the third embodiment, the device 103 formed on the wafer 100 is, for example, an integrated circuit such as IC (Integrated Circuit) or LSI (Large Scale Integration), or an image sensor such as CCD or CMOS.

Next, in this specification, the processing of the wafer cutting method according to the third embodiment will be described with reference to the drawings. As shown in FIG. 10, the wafer cutting method according to Embodiment 3 further includes target registration step 1031 and distance registration step 1032 in Embodiment 1, and kerf check step 1003 is changed to target check step 1033. It is.

The target registration step 1031 is a step of registering an arbitrary pattern of the device 103 as the target 180 for detecting the planned division line 102 . In the target registration step 1031, the control unit 60 captures an image including the target 180 by matching the imaging area 120 of the imaging unit 30 with the area including the target 180, and determines the planar shape and color of the target 180 in this image. is registered in the storage device of the control unit 60 .

Distance registration step 1032 is a step of measuring and registering distances 181 and 182 from target 180 registered in target registration step 1031 to dividing line 102 surrounding device 103 on which target 180 is formed. In the distance registration step 1032 , the control unit 60 first captures the planned division line 102 surrounding the device 103 on which the target 180 registered in the target registration step 1031 is formed by the imaging unit 30 , and includes the planned division line 102 . Get an image. In the distance registration step 1032, the control unit 60 next determines the position of the target 180 in the image containing the target 180 captured in the target registration step 1031 and the center line of the division line 102 in the image containing the division line 102. and the difference in the position of the imaging unit 30 between when the image including the target 180 was captured and when the image including the dividing line 102 was captured, from the target 180 registered in the target registration step 1031, Distances 181 and 182 to the dividing line 102 surrounding the device 103 on which the target 180 is formed are measured. At the distance registration step 1032 , the control unit 60 registers the measured distances 181 and 182 in the storage device of the control unit 60 .

Note that the target registration step 1031 and the distance registration step 1032 are performed after the holding step 1001 of the first wafer 100 when the wafers 100 of the same type are continuously processed. Processing is performed before the holding step 1001 as shown in FIG.

In the target check step 1033, after removing the cutting water 29 adhering to the surface 101 by injecting the air 49 to a position away from the cutting groove 110 by the distance 181, the position where the air 49 is injected is imaged. In this step, if the target 180 does not exist in the image, it is detected that the cutting position is misaligned. Like the kerf check step 1003, the target check step 1033 is performed after at least one cut groove 110 is formed by the cutting step 1002. FIG.

Specifically, the target check area to be removed of the cutting water 29 and imaged in the target check step 1033 is formed after the cutting grooves 110 are formed along the planned division lines 102 parallel to the X-axis direction, and , and before the cutting grooves 110 are formed along the planned dividing line 102 parallel to the Y-axis direction, a position apart from the cutting grooves 110 formed along the X-axis direction by a distance 181 in the +Y direction, and This area includes a position separated by a distance 182 in the +X direction from the planned division line 102 along the axial direction. After the cutting grooves 110 are formed along both the planned division lines 102 parallel to the X-axis direction and the Y-axis direction, the target check area extends from the cutting grooves 110 formed along the X-axis direction to the +Y direction. This area includes a position separated by a distance 181 and a position separated by a distance 182 in the +X direction from the cutting groove 110 formed along the Y-axis direction. In the third embodiment, the distances 181 and 182 are sufficiently longer than each side of the imaging area 120 of the imaging unit 30, so the target check area does not straddle the division line 102 or the cutting groove 110. FIG. Therefore, in the target check step 1033, first, the control unit 60 refers to the distances 181 and 182 registered in the distance registration step 1032, and moves the imaging unit 30 and the air injection unit 52 and the Z-axis movement unit 53. By moving the unit 40, the imaging area 120 of the imaging unit 30 is moved to the target check area.

In target check step 1033, after moving imaging area 120 of imaging unit 30 to the target check area, drying step 1041, imaging step 1042, and inspection step 1043 are sequentially performed as shown in FIG. The drying step 1041 and the imaging step 1042 are respectively the area in which the cutting water 29 is removed by injecting the air 49 from the air injection unit 40 and the area to be imaged by the imaging unit 30 in the drying step 1011 and the imaging step 1012 of the first embodiment. are changed to the target check area. In the inspection step 1043, the control unit 60 determines whether or not the target 180 exists in the image of the target check area captured in the imaging step 1042. If it is determined that the target 180 exists, the cutting position is not deviated. If it is determined that the target 180 does not exist, it is determined that the cutting position is misaligned, and the position of the cut groove 110 is confirmed. In the inspection step 1043, the control unit 60 determines whether or not the target 180 exists in the image of the target check area based on the image of the target check area and the planar shape and color of the target 180 registered in the target registration step 1031. is performed by pattern matching.

In step 1004 of the third embodiment, the control unit 60 determines whether or not it is possible to continue the cutting processing by the processing device 1 based on the determination result of the target check step 1033 . In step 1004, when the control unit 60 determines that the cutting position is not deviated in the target check step 1033, it determines that the cutting processing by the processing apparatus 1 can be continued (Yes in step 1004). , the process proceeds to step 1005 in FIG. In step 1004, when the control unit 60 determines that the cutting position is shifted in the target check step 1033, it determines that the cutting processing by the processing apparatus 1 can be continued (No in step 1004). , the cutting process by the processing device 1 is stopped.

In the wafer cutting method according to the third embodiment having the above configuration, the target 180 formed on each device 103 and the distances 181 and 182 from the target 180 to the dividing line 102 are further registered in the first embodiment. However, instead of the kerf check, it is confirmed whether or not the target 180 exists at a position separated from the cut groove 110 by a distance 181 . Therefore, in the wafer cutting method according to the third embodiment, the cutting water 29 is removed by jetting the air 49 and the image is captured in the target check area including the target 180 . There is no need to take an image, and the time required to confirm whether or not the target 180 exists is shorter than the time required for the kerf check. .

Further, in the wafer cutting method according to the third embodiment, since the target 180 is checked, the warp of the warped wafer 100 is released and the chip size device 103 moves. 2, when the line to be processed is cut but the center of the line to be divided 102 on the actual wafer 100 cannot be processed, or the processing position is greatly shifted and the device region 107 is cut into, which cannot be detected by the kerf check. There is an effect that it can be done.

In addition, the wafer cutting method according to the third embodiment can reduce the time required for the kerf check especially when the device 103 formed on the wafer 100 is an image sensor that causes little chipping and does not require chipping inspection. It is valid.

It should be noted that the wafer cutting method according to the third embodiment may further perform hairline alignment for correcting this hairline deviation 170, as in the second embodiment. will further play.

It should be noted that the present invention is not limited to the above embodiments. That is, various modifications can be made without departing from the gist of the present invention.

1 processing device 10 holding table 15 second holding table 20 processing unit 21 cutting blade 29 cutting water 30 imaging unit 49 air 100 wafer 101 surface 102 scheduled division line 107 device region 108 outer peripheral surplus region 110 cutting groove 180 target 181, 182 distance 210 Hairline

Claims (3)

A wafer cutting method for cutting a wafer having a device region in which a plurality of devices are formed and an outer peripheral surplus region surrounding the device region along a dividing line dividing the plurality of devices by a processing apparatus, the method comprising: ,
a holding step for holding the wafer on a holding table;
a cutting step of cutting the wafer held on the holding table with a cutting blade along the dividing lines to form cutting grooves while supplying cutting water to the processing point;
A kerf for confirming at least the position of the cutting groove by injecting air into the device region near the outer peripheral surplus region to remove cutting water adhering to the surface, and then imaging the device region where the air is jetted. a checking step;
A wafer cutting method comprising: The processing apparatus has a second holding table installed adjacent to the holding table and holding a dummy wafer,
The method for cutting the wafer is
A second cutting groove is formed in the dummy wafer with the cutting blade, and a deviation between the second cutting groove and the hairline of an imaging unit having a hairline, which is a line to be cut by the cutting blade, is measured. further comprising a hairline alignment step of correcting the positional relationship between the imaging unit and the cutting blade;
during the hairline alignment step, further performing a cleaning step of supplying cleaning water to the wafer held on the holding table to clean the surface of the wafer;
2. The wafer cutting method according to claim 1, wherein said kerf check step is performed after said cleaning step is performed. The method for cutting the wafer is
a target registration step of registering an arbitrary pattern of the device as a target for detecting the line to be divided;
a distance registration step of measuring and registering the distance from the target to the planned division line;
further comprising
The kerf check step includes:
When air is jetted to a position distant from the cutting groove to remove cutting water adhering to the surface, the position where the air is jetted is photographed, and the target does not exist in the photographed image. 2. The method of cutting a wafer according to claim 1, further comprising a target check step of detecting deviation of the cutting position.

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