JP7450460B2 - Wafer processing method - Google Patents

Description

The present invention relates to a wafer processing method.

In the device chip manufacturing process, a plurality of devices are formed on the front surface of a wafer, the back surface of the wafer is ground by a grinding device to thin the wafer, and then the wafer is divided into devices. On the surface of the wafer, a device region in which a plurality of devices are formed is surrounded by a peripheral surplus region in which no devices are formed. The materials such as metal and resin that are laminated in the device area are also laminated in the outer peripheral surplus area.

The material laminated in the peripheral excess area is more non-uniform than the material laminated in the device area, and its thickness is not precisely controlled. Therefore, the surface of the peripheral surplus region may protrude beyond the surface of the device region.

If the surface of the excess peripheral area protrudes from the surface of the device area, if a protective tape or substrate substrate is attached to the front surface of the wafer and the back side of the wafer is ground using a grinding machine, the excessive peripheral area may protrude. As a result, the outer peripheral portion of the wafer may be damaged. To deal with this problem, edge trimming is sometimes performed to cut the outer circumferential portion of the wafer into a circular shape before grinding the back surface of the wafer (for example, see Patent Document 1).

JP2012-043825A

However, when a material such as metal is cut with a cutting blade, burrs may be generated, and conversely, unevenness may occur. In addition, when edge trimming is performed, a step is formed between the device area and the excess outer area, so the grinding device cannot stably hold the excess outer area by suction, resulting in edge chipping during the grinding process. There is a fear. That is, there is a risk that the outer peripheral portion of the wafer may be damaged.

The present invention has been made in view of such problems, and an object thereof is to provide a wafer processing method that can reduce the thickness of the wafer while suppressing damage to the outer peripheral portion of the wafer.

In order to solve the above-mentioned problems and achieve the objects, the wafer processing method of the present invention includes a device region in which a plurality of devices are formed and a peripheral surplus region surrounding the device region, A method for processing a wafer in which the material forming the device is unevenly stacked in the surplus area and protrudes beyond the device area, the outer peripheral surface of the cutting blade being 3 degrees or less with respect to the rotation axis of the spindle to be mounted. a blade preparation step of preparing a cutting blade inclined at an angle of , a holding step of holding the wafer from the back side on a holding surface of a chuck table of the cutting device, and a holding step of holding the wafer from the back side on the holding surface of the chuck table of the cutting device; a removing step of rotating the chuck table while cutting the inclined outer peripheral surface of the cutting blade, cutting the excess outer peripheral area in a circular shape and removing the protruding material; and after performing the removing step. , a protective member disposing step of disposing a protective member on the front surface of the wafer including the device area and the outer peripheral surplus area; a grinding step of thinning by grinding, and after the removal step, the slanted slope of the outer peripheral surface is transferred, and the slanted surface of the outer peripheral surface is transferred from the periphery of the device region toward the outer periphery of the wafer. It is characterized by a thin sloped area.

In the wafer processing method, the blade preparation step includes holding a dressing board on the chuck table of the cutting device, cutting the dressing board with the cutting blade attached to a spindle, and applying a powder to the outer peripheral surface of the cutting blade. The inclined surface may be formed.

In the wafer processing method, in the blade preparation step, the cutting blade is positioned at a height to cut a predetermined amount into the dressing board, and in the removal step, the axis of the spindle is set from one side facing the device area. The dressing board may be cut by moving the cutting blade along the direction, and the cutting blade may be shaped into a shape whose diameter increases from the one side to the other side.

In the wafer processing method, after performing the blade preparation step and before performing the removing step, the cutting blade is cut into a groove forming board held on the chuck table, and the formed cutting groove is cut in the longitudinal direction. The cutting blade may include a shape inspection step of inspecting whether the angle of the inclined surface of the cutting blade is a predetermined angle based on the end shape of the cutting blade.

The wafer processing method of the present invention has the effect of reducing the thickness of the wafer while suppressing damage to the outer peripheral portion of the wafer.

FIG. 1 is a perspective view showing an example of a wafer to be processed by the wafer processing method according to the first embodiment. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is a flowchart showing the flow of the wafer processing method according to the first embodiment. FIG. 4 is a side view schematically showing, partially in section, the blade preparation step of the wafer processing method shown in FIG. FIG. 5 is a perspective view schematically showing the blade preparation step of the wafer processing method shown in FIG. FIG. 6 is an enlarged view of the VI section in FIG. 4. FIG. 7 is a side view schematically showing, partially in cross section, the holding step of the wafer processing method shown in FIG. FIG. 8 is a side view schematically showing, partially in section, the removal step of the wafer processing method shown in FIG. FIG. 9 is a cross-sectional view schematically showing the wafer after the removal step of the wafer processing method shown in FIG. FIG. 10 is a cross-sectional view schematically showing the step of providing a protective member in the wafer processing method shown in FIG. FIG. 11 is a side view schematically showing, partially in section, the grinding step of the wafer processing method shown in FIG. FIG. 12 is a flowchart showing the flow of the wafer processing method according to the second embodiment. FIG. 13 is a side view, partially in cross section, showing a state in which the cutting blade is positioned above the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. FIG. 14 is a side view, partially in cross section, showing a state in which a cutting blade cuts into the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. 12. FIG. 15 is a side view, partially in cross section, showing a state in which the cutting blade is retracted from above the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. 12. FIG. 16 is a side view, partially in cross section, showing a state in which a cut groove of the groove forming board held on the chuck table is imaged in the shape inspection step of the wafer processing method shown in FIG. 12. FIG. 17 is a diagram showing an example of an image of a cut groove of the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Further, the constituent elements 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. Moreover, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

[Embodiment 1]
A wafer processing method according to Embodiment 1 of the present invention will be explained based on the drawings. FIG. 1 is a perspective view showing an example of a wafer to be processed by the wafer processing method according to the first embodiment. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is a flowchart showing the flow of the wafer processing method according to the first embodiment.

The wafer processing method according to the first embodiment is a method for processing the wafer 1 shown in FIG. The wafer 1 to be processed in the wafer processing method according to the first embodiment is a disk-shaped wafer 1 whose substrate 2 is silicon (Si), sapphire (Al ₂ O ₃ ), gallium arsenide (GaAs), silicon carbide (SiC), or the like. semiconductor wafers or optical device wafers. As shown in FIG. 1, the wafer 1 includes a device region 3 and an outer peripheral surplus region 4 on the surface 5.

In the device region 3, a plurality of planned division lines 6 that intersect with each other are set on the surface 5, and a device 7 is formed in each region partitioned by the planned division lines 6. That is, the device area 3 is an area where a plurality of devices 7 are formed.

The device 7 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device), or a CMOS (Complementary Metal Oxide Semiconductor). The outer peripheral surplus area 4 is an area that surrounds the entire circumference of the device area 3 and in which no device 7 is formed.

Further, in the wafer 1, a functional layer 8, which is a material for forming the device 7, is laminated on the surface of the substrate 2. The functional layer 8 is a low dielectric constant insulating film (hereinafter referred to as a low-k film) made of an organic film such as an inorganic film such as SiOF or BSG (SiOB) or a polymer film such as polyimide or parylene. ) and a conductive film made of a conductive metal. The low-k film is laminated with a conductive film to form a device 7. The conductor film constitutes the circuit of the device 7. For this purpose, the device 7 is composed of low-k films stacked on each other and conductor films stacked between the low-k films.

In the device region 3, the thickness of the Low-k film and the conductive film constituting the functional layer 8 are uniformly formed to a thickness determined by the design of the device 7 and the like. In the peripheral surplus region 4, the thicknesses of the Low-k film and the conductive film constituting the functional layer 8 are not formed to the above-described predetermined thickness, but are formed non-uniformly. For this reason, in the first embodiment, the functional layer 8 in the peripheral surplus region 4 is non-uniformly laminated on the surface of the substrate 2, as shown in FIG. It protrudes in the thickness direction.

The wafer processing method according to the first embodiment includes removing the functional layer 8 that protrudes in the thickness direction from the surface 5 of the device region 3 in the peripheral surplus region 4 of the wafer 1, and grinding the wafer 1 to a predetermined thickness. This is a processing method that reduces the thickness. As shown in FIG. 3, the wafer processing method according to the first embodiment includes a blade preparation step 1001, a holding step 1002, a removing step 1003, a protective member disposing step 1004, and a grinding step 1005.

(Blade preparation step)
FIG. 4 is a side view schematically showing, partially in section, the blade preparation step of the wafer processing method shown in FIG. FIG. 5 is a perspective view schematically showing the blade preparation step of the wafer processing method shown in FIG. FIG. 6 is an enlarged view of the VI section in FIG. 4. In the blade preparation step 1001, the outer peripheral surface 12 of the cutting blade 11 of the cutting device 10 shown in FIGS. 4 and 5 is at an angle 100 of 3 degrees or less (shown in FIG. 6) with respect to the rotation axis 14 of the spindle 13 to be mounted. This is a step of preparing the cutting blade 11 formed on the inclined surface 15.

In the first embodiment, in the blade preparation step 1001, an operator or the like attaches the cutting blade 11 shown in FIG. It will be placed. The dressing board 20 is composed of a resin or ceramic bond material mixed with abrasive grains such as WA (white alundum, alumina type), GC (green carbonite, silicon carbide type), and in the first embodiment, a flat surface is used. It is formed into a plate shape with a rectangular shape and a constant thickness. The dressing board 20 wears out the cutting edge of the cutting blade 11 when the cutting edge of the cutting blade 11 cuts into the dressing board 20 .

Further, in the first embodiment, as shown in FIG. 5, the dressing board 20 is attached to an adhesive tape 22 having an annular frame 21 attached to its outer edge, and is attached to the holding surface 17 of the chuck table 16 via the adhesive tape 22. will be placed on. Further, in the first embodiment, the dressing board 20 may be formed with cutting grooves 23 for shaping the blade. The cutting groove 23 for shaping the blade is formed concave from the surface of the dressing board 20 and has an arcuate cross section, and the cutting groove 23 is formed in a straight line parallel to the rotating shaft 14 in the axial direction (hereinafter referred to as the Y-axis direction). It is formed over the entire length of the board 20. Note that the Y-axis direction is parallel to the horizontal direction and parallel to the longitudinal direction of the rotating shaft 14.

In the first embodiment, in the blade preparation step 1001, the cutting device 10 rotates the cutting blade 11 around the rotation axis 14 using the spindle 13, operates the suction source 18, and attaches the holding surface of the chuck table 16 via the adhesive tape 22. The dressing board 20 is held by suction at 17, and the annular frame 21 is clamped by a clamp portion (not shown). In the first embodiment, in the blade preparation step 1001, the cutting device 10 positions the lower end of the cutting blade of the cutting blade 11 in a position aligned with the blade shaping cutting groove 23 of the dressing board 20 along the rotation axis 14, and 4, the lower end of the cutting blade 11 is positioned at a height that cuts a predetermined amount 24 into the dressing board 20. Further, in the first embodiment, in the blade preparation step 1001, the cutting device 10 moves one side surface 111 facing the device area 3 closer to the dressing board 20 than the other side surface 112 in the cutting edge removal step 1003 of the cutting blade 11. Positioned in

In the first embodiment, in the blade preparation step 1001, the cutting device 10 moves the cutting blade 11 along the rotation axis 14 from one side 111 side. That is, the cutting device 10 relatively moves the cutting blade 11 and the chuck table 16 along the rotation axis 14 (ie, the Y-axis direction) in a direction in which one side surface 111 approaches the dressing board 20. In the first embodiment, in the blade preparation step 1001, the cutting device 10 moves the cutting blade 11 and the dressing board 20 from the position shown by the solid line in FIG. are relatively moved to cause the cutting edge of the cutting blade 11 to cut into the inner surface of the cutting groove 23. In the first embodiment, in the blade preparation step 1001, the cutting device 10 cuts the dressing board 20 with the cutting edge of the cutting blade 11 attached to the spindle 13, and also moves the cutting blade 11 along the rotation axis 14 to perform dressing. The inner surface of the cutting groove 23 of the board 20 is cut over the entire length.

In the first embodiment, in the blade preparation step 1001, the cutting device 10 expands the diameter of the cutting blade 11 attached to the spindle 13 from one side surface 111 side to the other side surface 112 side as shown in FIG. Shape it into the desired shape. Thus, in the first embodiment, in the blade preparation step 1001, the inclined surface 15 that is inclined with respect to the rotation axis 14 is formed on the outer circumferential surface 12 of the cutting blade 11. In Embodiment 1, the angle 100 of the inclined surface 15 with respect to the rotation axis 14 is 3 degrees, but in the present invention, the angle 100 may be greater than 0 degrees and less than or equal to 3 degrees. That is, in the first embodiment, in the blade preparation step 1001, the outer circumferential surface 12 is formed on the inclined surface 15 that is inclined at an angle 100 of 3 degrees or less with respect to the rotation axis 14. As described above, in the first embodiment, the machining conditions in the blade preparation step 1001 are such that the angle 100 of the inclined surface 15 is greater than 0 degrees and less than 3 degrees, and preferably 3 degrees. It is desirable to have one.

In the first embodiment, in the blade preparation step 1001, the cutting device 10 stops the operation of the suction source 18 to stop suctioning and holding the dressing board 20 to the chuck table 16, and releases the clamp on the annular frame 21 of the clamp section. Then, the dressing board 20 is carried out from the holding surface 17 of the chuck table 16. Note that in FIG. 6, the angle 100 is exaggerated and shown larger than the actual angle.

(holding step)
FIG. 7 is a side view schematically showing, partially in cross section, the holding step of the wafer processing method shown in FIG. The holding step 1002 is a step of holding the wafer 1 from the back surface 9 side on the holding surface 17 of the chuck table 16 of the cutting device 10.

In the first embodiment, in the holding step 1002, the wafer 1 is placed on the holding surface 17 of the chuck table 16 of the cutting device 10. In the first embodiment, the back surface 9 of the wafer 1 is attached to an adhesive tape 25 having an annular frame attached to the outer edge, and the back surface 9 side is placed on the holding surface 17 of the chuck table 16 via the adhesive tape 25. be done. In the first embodiment, the back surface 9 of the wafer 1 is fixed with the adhesive tape 25, but in the present invention, the back surface 9 does not need to be fixed with the adhesive tape 25. In the first embodiment, in the holding step 1002, the cutting device 10 operates the suction source 18 to attach the back surface 9 side of the wafer 1 to the holding surface 17 of the chuck table 16 via the adhesive tape 25, as shown in FIG. suction and hold, and clamp the annular frame with the clamp part.

(removal step)
FIG. 8 is a side view schematically showing, partially in section, the removal step of the wafer processing method shown in FIG. FIG. 9 is a cross-sectional view schematically showing the wafer after the removal step of the wafer processing method shown in FIG. In the removal step 1003, the chuck table 16 is rotated with the inclined outer circumferential surface 12 of the cutting blade 11 cutting into the outer circumferential excess area 4 of the wafer 1 held on the chuck table 16, and the outer circumferential excess area 4 is shaped into a circular shape. In this step, the functional layer 8 protruding from the device region 3 in the outer peripheral surplus region 4 is removed.

In Embodiment 1, in the removal step 1003, the cutting device 10 positions the lower end of the cutting blade 11 at a position aligned with the outer peripheral surplus area 4 of the wafer 1 in the X-axis direction, which is the processing feed direction, and The lower end of the cutting blade 11 is positioned at a height that cuts a predetermined amount from the front surface 5 side of the wafer 1 into the outer peripheral surplus region 4. The X-axis direction is parallel to the horizontal direction and perpendicular to the Y-axis direction. Note that the predetermined amount means that the height in the Z-axis direction of the end of the inclined surface 15 of the cutting blade 11 on the side 111 side is equal to the height of the Z-axis direction of the surface 5 of the device region 3 of the wafer 1 held on the chuck table 16. It is equal to or more than the height in the direction, and is an amount by which the outer peripheral surface of the cutting blade 11 can remove the functional layer 8 that protrudes from the device region 3 in the outer peripheral surplus region 4. Note that the Z-axis direction is a direction perpendicular to both the X-axis direction and the Y-axis direction.

In the first embodiment, in the removal step 1003, the cutting device 10 moves the cutting blade 11 and the chuck table 16 relatively along the X-axis direction in a direction in which the cutting blade 11 approaches the wafer 1, and performs cutting. When the lower end of the cutting blade of the cutting blade 11 cuts into the outer peripheral surplus area 4, and as shown in FIG. The wafer 1 is then rotated.

In Embodiment 1, in the removal step 1003, when the lower end of the cutting blade 11 cuts into the outer peripheral surplus region 4, one side surface 111 is closer to the device region 3 than the other side surface 112, that is, the inner periphery of the wafer 1. located on the side. In the first embodiment, in the removal step 1003, when the cutting device 10 cuts the cutting blade 11 over the entire circumference of the outer peripheral surplus region 4, the cutting blade 11 is retracted from the chuck table 16, and the suction source 18 is operated. , the suction and holding of the wafer 1 on the chuck table 16 is stopped, the annular frame 21 of the clamp section is unclamped, and the wafer 1 is carried out from the holding surface 17 of the chuck table 16 .

In this way, in Embodiment 1, the cutting device 10 cuts the outer circumferential surplus region 4 of the wafer 1 in a circular shape over the entire circumference, and removes the functional layer 8 that protrudes beyond the device region 3, as shown in FIG. . In addition, the inclined surface 15 of the outer peripheral surface 12 of the cutting blade 11 is transferred to the surplus outer peripheral region 4 of the wafer 1 after performing the removal step 1003, and the inclined surface 15 of the outer peripheral surface 12 of the cutting blade 11 is transferred from the outer peripheral edge of the device region 3 toward the outer peripheral edge of the wafer 1. As a result, an inclined region 401 becomes gradually thinner. Note that the angle 402 between the inclined region 401 and the surface 5 of the device region 3 is equal to the angle 100 of the cutting blade 11 described above. The fact that the angle 402 of the inclined region 401 with the surface 5 of the device region 3 is equal to the angle 100 of the cutting blade 11 means that the inclined surface 15 of the outer peripheral surface 12 of the cutting blade 11 has been transferred to the outer peripheral surplus region 4. It shows. Note that in FIG. 9, the angle 402 is exaggerated and shown larger than the actual angle.

(Protective member placement step)
FIG. 10 is a cross-sectional view schematically showing the protective member disposing step of the wafer processing method shown in FIG. 3. FIG. The protective member disposing step 1004 is a step of disposing the protective member 30 on the surface 5 of the wafer 1 including the device region 3 and the peripheral surplus region 4 after the removing step 1003 is performed.

In the first embodiment, in the protective member disposing step 1004, as shown in FIG. Peel off. In Embodiment 1, the protective tape that is the protective member 30 has a flexible base layer made of a non-adhesive synthetic resin as a whole, and an adhesive synthetic resin laminated on the base layer. and an adhesive layer that is adhered to the surface 5 of the wafer 1. Further, in the present invention, in the protective member disposing step 1004, a disk-shaped substrate substrate made of a hard material such as glass or silicon is attached to the surface 5 of the wafer 1 in addition to the protective tape as the protective member 30. You can also paste it.

(Grinding step)
FIG. 11 is a side view schematically showing, partially in section, the grinding step of the wafer processing method shown in FIG. The grinding step 1005 is a step in which the chuck table 41 of the grinding device 40 holds the wafer 1 under suction through the protection member 30 and grinds the back surface 9 of the wafer 1 to thin the wafer 1.

In the first embodiment, in the grinding step 1005, as shown in FIG. 11, the grinding device 40 places the front surface 5 side of the wafer 1 on the holding surface 42 made of porous ceramic of the chuck table 41 via the protective member 30. Then, the holding surface 17 is suctioned by a vacuum suction source (not shown) to suction and hold the front surface 5 side of the wafer 1 through the protection member 30. In the grinding step 1005, the grinding device 40 rotates the chuck table 41 around the axis and rotates the grinding wheel 44 of the grinding unit 43 around the axis to bring it into contact with the back surface 9 of the wafer 1, thereby grinding the back surface 9. . In the grinding step 1005, the grinding device 40 grinds and thins the wafer 1 until it reaches a predetermined thickness. In the grinding step 1005, when the grinding device 40 thins the wafer 1 to a predetermined thickness, the wafer processing method ends.

In the wafer processing method according to the first embodiment described above, the outer peripheral surplus area 4 is formed by using the inclined surface 15 of the cutting blade 11 that is inclined with respect to the Y-axis direction at an extremely small angle 100 with respect to the rotation axis 14 of 3 degrees or less. Since the surface is cut, it is possible to suppress the formation of steps while suppressing the generation of burrs. Furthermore, in the wafer processing method, the above-mentioned inclined region 401 is formed in the outer circumferential surplus region 4 of the wafer 1 in the removal step 1003, so even if a burr is generated, the generated burr will spread along the inclined region 401. Therefore, protrusion from the surface 5 of the device region 3 in the thickness direction can be suppressed. For this reason, the wafer processing method according to the first embodiment has the effect that the wafer 1 can be reliably fixed to the outer circumference during the grinding step 1005, and damage to the outer circumference of the wafer 1 can be suppressed. As a result, the wafer processing method according to the first embodiment has the effect that the wafer 1 can be made thinner while suppressing damage to the outer peripheral portion of the wafer 1.

Further, in the wafer processing method according to the first embodiment, since the inclined surface 15 of the cutting blade 11 is formed after the cutting blade 11 is mounted on the spindle 13 of the cutting device 10, the angle 100 with respect to the rotation axis 14 is 3 degrees or less. Even the inclined surface 15 having a very small angle can be reliably formed.

[Embodiment 2]
A wafer processing method according to Embodiment 2 of the present invention will be described based on the drawings. FIG. 12 is a flowchart showing the flow of the wafer processing method according to the second embodiment. FIG. 13 is a side view, partially in cross section, showing a state in which the cutting blade is positioned above the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. FIG. 14 is a side view, partially in cross section, showing a state in which a cutting blade cuts into the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. 12. FIG. 15 is a side view, partially in cross section, showing a state in which the cutting blade is retracted from above the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. 12. FIG. 16 is a side view, partially in cross section, showing a state in which a cut groove of the groove forming board held on the chuck table is imaged in the shape inspection step of the wafer processing method shown in FIG. 12. FIG. 17 is a diagram showing an example of an image of the cut groove of the groove forming board held on the chuck table in the shape inspection step of the wafer processing method shown in FIG. 12. 12, FIG. 13, FIG. 14, FIG. 15, FIG. 16, and FIG. 17, the same parts as those in Embodiment 1 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 12, the wafer processing method according to the second embodiment is the same as the first embodiment except that it includes a shape inspection step 1010 that is performed after the blade preparation step 1001 and before the removal step 1003. . In the second embodiment, the wafer processing method includes performing a shape inspection step 1010 after performing the blade preparation step 1001 and before performing the holding step 1002, but in the present invention, the removal step is performed after the blade preparation step 1001 is performed. As long as the shape inspection step 1010 is executed before the holding step 1003 is executed, the shape inspection step 1010 is not limited to being executed before the holding step 1002 is executed.

In the shape inspection step 1010, the cutting blade 11 is cut into the groove forming board 26 held on the chuck table 16, and the shape of the longitudinal end 28 of the formed cutting groove 27 (shown in FIG. 14 etc.) is checked. This is a step of inspecting whether the angle 100 of the inclined surface 15 of the cutting blade 11 is greater than a predetermined angle of 0 degrees and less than 3 degrees.

In the second embodiment, in the shape inspection step 1010, the groove forming board 26 is placed on the holding surface 17 of the chuck table 16 of the cutting device 10. In the first embodiment, the groove forming board 26 is formed into a plate shape with a rectangular planar shape and a constant thickness. The groove forming board 26 is made of a material, such as silicon or the same material as the substrate 2 of the wafer 1, so that when the cutting blade 11 is cut, the cutting groove 27 is formed without wasting the cutting blade 11 as much as possible. .

In the second embodiment, in the shape inspection step 1010, the cutting device 10 operates the suction source 18 to suck and hold the groove forming board 26 on the holding surface 17 of the chuck table 16, and as shown in FIG. The cutting blade 11 rotated by is positioned above the groove forming board 26 which is suctioned and held by the holding surface 17 of the chuck table 16. In the second embodiment, in the shape inspection step 1010, the cutting device 10 lowers the cutting blade 11 along the Z-axis direction, and as shown in FIG. 26 to form a cutting groove 27 in the groove forming board 26.

In the second embodiment, in the shape inspection step 1010, as shown in FIG. 15, the cutting device 10 raises the cutting blade 11 along the Z-axis direction and holds the groove forming board 26 from below the cutting blade 11. The chuck table 16 that has been removed is evacuated. In the second embodiment, in the shape inspection step 1010, the cutting device 10 moves the imaging device 29 of the cutting device 10 above the groove forming board 26 which is suction-held by the holding surface 17 of the chuck table 16, as shown in FIG. , and the groove forming board 26 is imaged by the imaging device 29 to obtain an image 200 including both ends 28 (in the present invention, at least one end 28 is included) of the cut groove 27 shown in FIG. get.

In the second embodiment, in the shape inspection step 1010, the cutting device 10 determines, from the image 200 shown in FIG. The distance 271 in the X-axis direction and the width 272 of the cutting groove 27 are calculated, and the angle 100 of the inclined surface 15 is calculated from the calculated distance 271 and width 272. In the second embodiment, in the shape inspection step 1010, the cutting device 10 determines whether the calculated angle 100 of the inclined surface 15 is greater than 0 degrees and less than 3 degrees. In the second embodiment, in the shape inspection step 1010, if it is determined that the angle 100 of the inclined surface 15 calculated by the cutting device 10 is greater than 0 degrees and less than 3 degrees, the wafer processing method is continued, and the cutting device If it is determined that the angle 100 of the inclined surface 15 calculated by step 10 is greater than 0 degrees and not less than 3 degrees, the wafer processing method is temporarily stopped and the operator is notified.

The wafer processing method according to the second embodiment cuts the outer peripheral surplus region 4 with the inclined surface 15 of the cutting blade 11 that is inclined with respect to the Y-axis direction at an extremely small angle 100 of 3 degrees or less with respect to the rotation axis 14. Therefore, while suppressing the occurrence of burrs, it is possible to suppress the formation of steps, and similarly to the first embodiment, it is possible to reduce the thickness of the wafer 1 while suppressing damage to the outer periphery of the wafer 1. play.

Furthermore, since the wafer processing method according to the second embodiment includes a shape inspection step 1010 that is performed after the blade preparation step 1001 and before the removal step 1003, the shape of the inclined surface 15 is also inspected by the cutting device 10. This has the effect of being able to maintain a stable shape.

Next, the inventor of the present invention confirmed the effects of the wafer processing method according to the first embodiment. The results are shown in Table 1 below.

In addition, in the confirmation of Table 1, the cutting blades 11 of the present invention 1, the present invention 2, the comparative example 1, and the comparative example 2 were formed in which the angle 100 of the inclined surface 15 was different from each other, and the cutting blades 11 were removed with each of these cutting blades 11. After carrying out step 1003, the presence or absence of damage to the wafer 1, especially at the outer periphery, in the grinding step 1005 was checked.

Inventive product 1 is a cutting blade 11 with an angle of 100 of 1 degree, Inventive product 2 is a cutting blade 11 with an angle of 100 of 3 degrees, and comparative example 1 has an angle of 100 of 0 degrees (i.e., the outer periphery). Comparative Example 2 is a cutting blade 11 in which the surface 12 is parallel to the rotation axis 14 and no inclined surface 15 is formed, and Comparative Example 2 is a cutting blade 11 in which the angle 100 is 5 degrees.

In Comparative Example 1, after the removal step 1003, burrs are formed on the outer periphery of the wafer 1 that protrude in the thickness direction from the surface 5 of the device region 3, so during the grinding step 1005, the outer periphery of the wafer 1 is The outer peripheral edge of the wafer 1 was damaged because the wafer 1 could not be held by suction on the holding surface 17 of the wafer 1. Further, in Comparative Example 1, when the cutting blade 11 is cut into the outer peripheral surplus region 4 in the removal step 1003 to form a level difference in the outer peripheral surplus region 4 that is lower than the device region 3, the outer peripheral region of the wafer 1 is removed during the grinding step 1005. The outer peripheral edge of the wafer 1 was damaged because the peripheral edge could not be suctioned and held on the holding surface 17 of the chuck table 16. In addition, in Comparative Example 2, the outer circumferential edge of the wafer 1 and the protection member 30 did not come into close contact with each other, and the outer circumferential edge of the wafer 1 could not be suctioned and held on the holding surface 17 of the chuck table 16 during the grinding step 1005. The outer rim of was damaged.

In contrast to Comparative Example 1 and Comparative Example 2, in Inventive Product 1 and Inventive Product 2, the outer peripheral edge of the wafer 1 and the protective member 30 are in close contact with each other, and the outer peripheral edge of the wafer 1 is could be suctioned and held on the holding surface 17 of the chuck table 16, and the outer peripheral edge of the wafer 1 was not damaged. Therefore, according to Table 1, by setting the angle 100 of the inclined surface 15 to more than 0 degrees and less than 3 degrees, it is possible to reduce the thickness of the wafer 1 while suppressing damage to the outer periphery of the wafer 1. It has become clear that it is effective.

Note 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 invention.

1 Wafer 3 Device area 4 Surplus outer area 5 Surface 7 Device 8 Functional layer (material)
9 Back surface 10 Cutting device 11 Cutting blade 12 Outer peripheral surface 13 Spindle 14 Rotating shaft (axial direction)
15 Inclined surface 16 Chuck table 17 Holding surface 20 Dressing board 24 Predetermined amount 26 Groove forming board 27 Cutting groove 28 End 30 Protective member 40 Grinding device 41 Chuck table 42 Holding surface 100 Angle 111 One side 112 Other side 401 Incline Area 1001 Blade preparation step 1002 Holding step 1003 Removal step 1004 Protective member placement step 1005 Grinding step 1010 Shape inspection step

Claims (4)

The surface includes a device region in which a plurality of devices are formed, and an outer peripheral surplus region surrounding the device region, and the material forming the device is nonuniformly laminated in the peripheral surplus region and protrudes from the device region. A wafer processing method,
a blade preparation step of preparing a cutting blade in which the outer peripheral surface of the cutting blade is inclined at an angle of 3 degrees or less with respect to the rotation axis of the spindle to be attached;
a holding step of holding the wafer from the back side on a holding surface of a chuck table of the cutting device;
The chuck table is rotated with the inclined outer circumferential surface of the cutting blade cutting into the excess outer circumferential area of the wafer held by the chuck table, and the excess outer circumferential area is cut into a circular shape to cut the protruding groove. a removal step of removing the material;
After performing the removing step, a protective member disposing step of disposing a protective member on the surface of the wafer including the device region and the peripheral surplus region;
a grinding step of sucking and holding the wafer through the protective member on a chuck table of the grinding device, and grinding the back surface of the wafer to make it thin;
A method for processing a wafer, in which the peripheral surplus area after performing the removal step is a sloped area where an inclined surface of the peripheral surface is transferred and becomes thinner from the peripheral edge of the device area toward the outer periphery of the wafer. The blade preparation step includes holding the dressing board on the chuck table of the cutting device, cutting the dressing board with the cutting blade attached to a spindle, and forming the inclined surface on the outer peripheral surface of the cutting blade. The method for processing a wafer according to item 1. In the blade preparation step, the cutting blade is positioned at a height to cut a predetermined amount into the dressing board, and in the removal step, the cutting blade is moved along the axial direction of the spindle from one side facing the device area. 3. The method of processing a wafer according to claim 2, wherein the dressing board is cut by moving the dressing board, and the cutting blade is shaped into a shape whose diameter increases from the one side surface to the other side surface. After performing the blade preparation step and before performing the removing step, the cutting blade is cut into the groove forming board held on the chuck table, and the cutting blade is cut from the longitudinal end shape of the formed cutting groove. 4. The wafer processing method according to claim 1, further comprising a shape inspection step of inspecting whether the angle of the inclined surface of the blade is a predetermined angle.

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