JP2015198183A - Processing method of wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method of a wafer which allows for formation of a groove having a desired width, even with a cutting blade thinner than the desired width of a groove to be formed in a dividing line.SOLUTION: A processing method of a wafer where devices are formed in regions on the surface sectioned by a plurality of dividing lines includes a shallow groove formation step of forming a shallow groove of desired width along the dividing lines by means of a cutting blade attached to a rotating shaft, and a processing step of processing the wafer, subjected to the shallow groove formation step, along the shallow groove. The shallow groove formation step forms a shallow groove of a desired width, by cutting along the dividing lines while inclining the rotating shaft so that the cutting direction of the cutting blade inclines for the dividing lines.

Description

  The present invention relates to a wafer processing method for cutting a wafer having a device formed in a region partitioned by a plurality of division lines on the surface along the division lines.

  For example, in a semiconductor device manufacturing process, devices such as ICs and LSIs are formed in a plurality of regions partitioned by scheduled dividing lines formed in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer. Individual devices are manufactured by dividing each formed region along a planned division line. As a dividing device for dividing a semiconductor wafer, a cutting device as a dicing device is generally used. The cutting apparatus includes a chuck table that holds a workpiece, and a cutting unit that includes a cutting blade that cuts the workpiece held on the chuck table. The chuck table is relatively rotated while the cutting blade is rotated. It cuts by letting it cut and feed.

  In addition, a test element group (TEG) for testing the function of the device on the planned dividing line is used to cut a wafer in which a test metal pattern or a laminate such as a passivation film is laminated with a cutting blade along the planned dividing line. When cut, the cutting blade is clogged or chipping occurs on the side surfaces of the divided devices. In order to solve such a problem, before the wafer is cut along the planned division line, a relatively shallow groove is formed by a cutting blade having a thickness corresponding to the planned division line, and a metal pattern or a passivation film is laminated. A wafer processing method in which an object is removed and then cut along a division line from which a laminate is removed by a thin cutting blade has been put into practical use (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2003-334751

  Thus, the cutting blade having a thickness corresponding to the planned dividing line cannot be maintained at a thickness corresponding to the width of the planned dividing line due to wear on the side surface, and has a thickness corresponding to the scheduled dividing line relatively frequently. There is a problem that it is uneconomical to replace the cutting blade and discard the used worn cutting blade.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is that a groove having a width desired to be formed can be formed even with a cutting blade having a thickness thinner than the groove width desired to be formed on the division line. It is to provide a method for processing a wafer.

In order to solve the main technical problem, according to the present invention, a wafer processing method in which a device is formed in an area partitioned by a plurality of division lines on the surface,
A shallow groove forming step of forming a shallow groove having a desired width along the line to be divided by a cutting blade attached to the rotary shaft;
Processing along the shallow groove of the wafer on which the shallow groove forming step has been performed, and
The shallow groove forming step forms a shallow groove having a desired width by cutting along the planned dividing line in a state where the rotation axis is inclined so that the cutting direction of the cutting blade is inclined with respect to the planned dividing line.
A method for processing a wafer is provided.

  In the processing step, the wafer is cut along the shallow grooves formed along the planned dividing lines and divided into individual devices.

The shallow groove forming step in the wafer processing method according to the present invention is performed by cutting along the planned dividing line with the rotation axis tilted so that the cutting direction of the cutting blade is inclined with respect to the planned dividing line. Since the shallow groove having the desired width can be formed along the line to be divided even if the cutting blade is worn, the cutting blade to be discarded can be used effectively. Is.
Further, the shallow groove forming step in the wafer processing method according to the present invention is performed by cutting along the planned dividing line with the rotating shaft tilted so that the cutting direction of the cutting blade is inclined with respect to the planned dividing line. Since a shallow groove having a width is formed, even when there is no cutting blade having a thickness corresponding to the division line, a shallow groove having a desired width is formed along the division line using a thin cutting blade for cutting. I can do it.

The perspective view of the semiconductor wafer as a wafer processed by the processing method of the wafer by this invention The perspective view which shows the state which affixed the semiconductor wafer shown in FIG. 1 on the dicing tape with which the cyclic | annular flame | frame was mounted | worn. The perspective view of the cutting device for enforcing the processing method of the wafer by the present invention. The top view of the 1st spindle unit and the 2nd spindle unit which comprise the 1st cutting means and the 2nd cutting means of the cutting device shown in FIG. Explanatory drawing of the shallow groove | channel formation process in the processing method of the wafer by this invention. Explanatory drawing of the shallow groove | channel formation process in the processing method of the wafer by this invention. Explanatory drawing of the shallow groove | channel formation process and processing process in the processing method of the wafer by this invention. Explanatory drawing of the manufacturing process in the processing method of the wafer by this invention. 1 is a perspective view of a semiconductor wafer on which a shallow groove forming step and a processing step are performed in a wafer processing method according to the present invention. The principal part sectional drawing which expands and shows the cutting blade worn out by implementing the shallow groove formation process in the processing method of the wafer by this invention. Explanatory drawing which shows the relationship between the division | segmentation scheduled line formed in the semiconductor wafer in the manufacturing process of the processing method of the wafer by this invention, and a cutting blade. The principal part expanded sectional view of the semiconductor wafer in which the shallow groove | channel formation process in the processing method of the wafer by this invention was implemented. The principal part expanded sectional view of the semiconductor wafer in which the shallow groove | channel formation process and the processing process in the processing method of the wafer by this invention were implemented.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a wafer processing method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a semiconductor wafer as a wafer processed by the wafer processing method according to the present invention. A semiconductor wafer 10 shown in FIG. 1 is formed of a silicon wafer, and a plurality of regions are defined by a plurality of division lines 11 arranged in a lattice pattern on a surface 10a, and devices 12 such as ICs and LSIs are formed in the partitioned regions. Is formed. Note that a plurality of test metal patterns 13 made of copper (Cu) called test element groups (TEG) for testing the function of the device 12 are partially disposed on the division line 11 of the semiconductor wafer 10. Has been. As shown in FIG. 2, the semiconductor wafer 10 thus configured has a back surface 10b attached to a dicing tape T made of a synthetic resin sheet such as polyolefin mounted on an annular frame F (wafer supporting step). Therefore, the surface 10a of the semiconductor wafer 10 is on the upper side.

FIG. 3 is a plan view showing a schematic configuration of a cutting apparatus for carrying out the wafer processing method according to the present invention.
The cutting device 1 shown in FIG. 3 includes a stationary base 2. A chuck table mechanism 3 is disposed on the stationary base 2 to hold the workpiece and move it in the cutting feed direction indicated by the arrow X.

  The chuck table mechanism 3 in the illustrated embodiment includes a guide rail 31 disposed on the upper surface of the stationary base 2 along a cutting feed direction indicated by an arrow X. A support base 32 is disposed on the guide rail 31 so as to be movable along the guide rail 31. A cylindrical member 33 is disposed on the support base 32, and a chuck table 34 having a holding surface 34a at the upper end of the cylindrical member 33 is rotatably disposed. The chuck table 34 sucks and holds the workpiece placed on the holding surface 34a by suction means (not shown). The chuck table 34 is provided with a clamp 341 for fixing the annular frame F. The chuck table 34 is appropriately rotated by a pulse motor (not shown) disposed in the cylindrical member 33. A cover member 35 having holes for inserting the chuck table 34 and covering the support base 32 is disposed at the upper end of the cylindrical member 33.

  Continuing the description with reference to FIG. 3, the chuck table mechanism 3 in the illustrated embodiment includes a cutting feed means 36 for moving the chuck table 34 along the guide rail 31 in the cutting feed direction indicated by the arrow X. Yes. The cutting feed means 36 is composed of a known ball screw mechanism.

  The illustrated cutting apparatus 1 includes a gate-shaped support frame 4 disposed on the stationary base 2 across a guide rail 31. The gate-shaped support frame 4 includes a first column part 41, a second column part 42, and a cutting feed direction indicated by an arrow X by connecting the upper ends of the first column part 41 and the second column part 42. It comprises a support portion 43 disposed along the indexing feed direction indicated by an orthogonal arrow Y, and an opening 44 that allows movement of the chuck table 34 is provided in the center portion. A guide rail 431 is provided on one surface of the support portion 43 along the index feed direction indicated by the arrow Y.

  The illustrated cutting apparatus 1 includes a first cutting means 5a and a second cutting means 5b that are movably disposed along a guide rail 431 provided on a support portion 43 of the support frame 4. Yes. The first cutting means 5a and the second cutting means 5b include a first index movement base 51a and a second index movement base 51b, and the first index movement base 51a and the second index movement base. A first cut moving base 52a and a second cut moving base 52b supported on the base 51b so as to be movable in the cut feeding direction indicated by the arrow Z, and the first cut moving base 52a and the second cut The first spindle unit support member 53a and the second spindle unit support member 53b mounted on the moving base 52b, and the first spindle unit support member 53a and the second spindle unit support member 53b mounted on the first base unit support member 53b. One spindle unit 64a and a first spindle unit 64b are provided. The first index movement base 51a and the second index movement base 51b are respectively moved along the guide rail 431 by the first index feed means 510a and the second index feed means 510b each having a known ball screw mechanism. It is configured to move in the index feed direction indicated by Y. The first cutting movement base 52a and the second cutting movement base 52b are respectively divided into a first indexing movement base by a first cutting feeding means 520a and a first cutting feeding means 520b each having a known ball screw mechanism. It is configured to be moved in a cutting feed direction indicated by an arrow Z along a guide groove (not shown) provided in the table 51a and the second index movement base 51b. The first spindle unit support member 53a and the second spindle unit support member 53b are supported parts 531a and 531b extending in the vertical direction, respectively, and a mounting part extending horizontally at right angles from the lower ends of the supported parts 531a and 531b. 532a and 532b, and supported portions 531a and 531b are mounted on the first cut base 52a and the second cut base 52b, respectively. The first spindle unit 64a and the second spindle unit 64b are mounted on the lower surfaces of the mounting portions 532a and 532b of the first spindle unit support member 53a and the second spindle unit support member 53b thus configured, respectively. .

  As shown in FIGS. 3 and 4, the first spindle unit 64a and the second spindle unit 64b are respectively a first spindle housing 641a and a second spindle housing 641b, and the first spindle housing 641a and second spindle housing 641a. The first rotary spindle 642a and the second rotary spindle 642b rotatably supported by the spindle housing 641b, and the first cutting mounted on one end of the first rotary spindle 642a and the second rotary spindle 642b. And a first servo motor 644a and a second servo motor 644b that respectively rotate and drive the blade 643a, the second cutting blade 643b, and the first rotary spindle 642a and the second rotary spindle 642b. The axis direction of the rotary spindle 642a and the second rotary spindle 642b is indicated by the arrow Y It is arrange | positioned along the index feed direction shown by. Accordingly, the first cutting blade 643a and the second cutting blade 643b are disposed to face each other on the same axis. In the illustrated embodiment, the thickness of the first cutting blade 643a is set to 100 μm, for example, and the thickness of the second cutting blade 643b is set to 30 μm, for example.

  In the illustrated embodiment, the first spindle housing 641a of the first spindle unit 41a has a fastening bolt 65 for mounting on the mounting portion 532a of the first spindle unit support member 53a as shown in FIGS. As shown in FIG. 4, the center of the chuck table 34 can be inclined with respect to the indexing feed direction indicated by the arrow Y in a plane parallel to the holding surface 34 a as shown by a two-dot chain line in FIG. 4. Accordingly, the first spindle unit 64a is inclined with respect to the indexing feed direction indicated by the arrow Y in a plane parallel to the holding surface 34a of the chuck table 34, and therefore the first cutting unit mounted on the first spindle unit 64a. The cutting direction of the blade 643a (the direction perpendicular to the axis of the first rotary spindle 642) is inclined with respect to the cutting feed direction indicated by the arrow X, which is the cutting direction.

The illustrated cutting apparatus 1 is configured as described above, and a wafer processing method performed using the cutting apparatus 1 will be described. First, by forming a shallow groove along the planned division line 11 of the semiconductor wafer 10, the test metal pattern 13 formed on the surface of the planned division line 11 is removed, and the division plan with the shallow groove formed is formed. A conventional processing method for cutting the semiconductor wafer 10 along the line 11 will be described.
As shown in FIG. 2, the semiconductor wafer 10 supported on the annular frame F via the dicing tape T places the dicing tape T side on the chuck table 34 of the cutting apparatus 1 shown in FIG. Then, by operating a suction means (not shown), the semiconductor wafer 10 is sucked and held on the chuck table 34 via the dicing tape T. Therefore, the semiconductor wafer 10 is held with the surface 10a facing upward. The annular frame F is fixed by a clamp 341. The semiconductor wafer 10 sucked and held on the chuck table 34 via the dicing tape T in this way is cut by the planned dividing line 11 formed in a predetermined direction by performing a known alignment operation, as indicated by an arrow X. Positioned parallel to the feed direction.

  Next, the chuck table 34 that sucks and holds the semiconductor wafer 10 is moved to a processing region by the first cutting means 5a and the second cutting means 5b. Then, as shown in FIG. 5A, the leftmost division plan in the figure on the division line 11 of the semiconductor wafer 10 in which the first cutting blade 643a of the first spindle unit 64a is sucked and held by the chuck table 34 is shown. A position corresponding to the line 11 is positioned with a predetermined cutting depth HI. At this time, the first cutting blade 643a is located above the dicing tape T exposed on the outer peripheral edge of the semiconductor wafer 10 and the annular frame F on the extension line of the division line 11 as indicated by the solid line in FIG. Positioned. Note that the second cutting blade 643b of the second spindle unit 64b is positioned on the left side of the semiconductor wafer 10 as shown in FIG. Next, the first cutting blade 643a is rotated in the direction indicated by the arrow A, and the chuck table 34 is cut and fed in the direction perpendicular to the paper surface in FIG. 5A and in the direction indicated by the arrow X1 in FIG. Thus, as shown in FIG. 5B, a shallow groove G1 having a predetermined depth HI is formed along the leftmost division line 11 in the drawing of the semiconductor wafer 10 (shallow groove forming step). In the cutting feed, the first cutting blade 643a is exposed between the outer peripheral edge (right end in FIG. 6) of the semiconductor wafer 10 and the annular frame F as indicated by a two-dot chain line in FIG. The chuck table 34 is moved until it is located above the tape T. As a result, the test metal pattern 13 formed on the surface of the division line 11 is removed. Thus, if the shallow groove G1 is formed along the leftmost dividing line 11 in FIG. 5B of the semiconductor wafer 10, the first cutting blade 643a of the first spindle unit 64a is moved upward. A predetermined amount is moved to the right in FIG. 5 and is fed to the right by an amount corresponding to the interval between the division lines 11, and the chuck table 34 is moved in the direction opposite to the direction indicated by the arrow X 1 in FIG. The relative position of the cutting blade 643a and the semiconductor wafer 10 in the direction indicated by the arrow X1 is positioned at the position indicated by the solid line in FIG. Next, the first cutting blade 643a is cut and fed downward by a predetermined amount and positioned at a position corresponding to the second division planned line 11 from the left in FIG. 5 with a predetermined cutting depth HI. Then, as described above, the first cutting blade 643a is rotated and the chuck table 34 is cut and fed in the direction indicated by the arrow X1 in FIG. A shallow groove G1 having a predetermined depth HI corresponding to the width of the planned division line 11 is formed.

  As described above, if, for example, the shallow groove G1 is formed along the two division lines 11 by the first cutting blade 643a of the first spindle unit 64a, the first cutting blade 643a has the first groove as shown in FIG. The first cutting blade 643a of one spindle unit 64a is positioned with a predetermined cutting depth HI at a position corresponding to the third division line 11 from the left in the drawing of the semiconductor wafer 10, and the second spindle unit 64b The second cutting blade 643b is positioned with a cutting depth H2 reaching the dicing tape T at a position corresponding to the planned division line 11 where the leftmost planned division line 11 is formed in the drawing of the semiconductor wafer 10. Therefore, the second cutting blade 643b is positioned at the center position in the width direction of the shallow groove G1 formed by the first cutting blade 643a as described above. At this time, the second cutting blade 643b is formed on the dicing tape T exposed between the outer peripheral edge of the semiconductor wafer 10 and the annular frame F on the extension line of the division line 11 as shown by a solid line in FIG. Positioned on top. As described above, the first cutting blade 643a is dicing exposed between the outer peripheral edge of the semiconductor wafer 10 and the annular frame F on the extension line of the division line 11 as shown by the solid line in FIG. Positioned above the tape T. Next, the first cutting blade 643a and the second cutting blade 643b are rotated in the direction indicated by the arrow A, and the chuck table 34 is moved in the direction perpendicular to the paper surface in FIG. Cut and feed in the direction shown. As a result, as shown in FIG. 7B, a cutting groove G2 having a depth H3 from the bottom of the shallow groove G1 along the shallow groove G1 formed in the leftmost dividing line 11 in the drawing of the semiconductor wafer 10. Is formed (processing step), and a shallow groove G1 having a predetermined depth HI is formed along the third scheduled division line 11 from the left in the drawing. Note that the cutting feed is performed so that the first cutting blade 643a is indicated by a two-dot chain line in FIG. 6 and the second cutting blade 643b is indicated by a two-dot chain line in FIG. The chuck table 34 is moved until it reaches a dicing tape T exposed between the right end (in FIG. 6 and FIG. 8) and the annular frame F. Accordingly, the dicing tape T exposed between the outer peripheral edge of the semiconductor wafer 10 and the annular frame F is formed with a cutting groove G2 by the second cutting blade 643b as shown in FIG. By repeating the above operation, the shallow groove G1 and the cutting groove G2 are formed along the planned dividing line 11 formed in the predetermined direction of the semiconductor wafer 10, and the cutting groove G2 is formed also in the dicing tape T. The wafer 10 is cut along the planned division line 11.

However, when the first cutting blade 643a is subjected to the shallow groove forming step, the side surface is worn and the outer peripheral edge is tapered as shown in FIG. 10, so that the thickness corresponding to the width of the division line 11 cannot be maintained. Therefore, when the first cutting blade 643a is worn as shown in FIG. 10, it is necessary to replace the used cutting blade with a new cutting blade, and this is uneconomical.
Therefore, when the first cutting blade 643a is worn as shown in FIG. 10, in the wafer processing method according to the present invention, the shallow groove forming step is performed as follows.

  In order to carry out the shallow groove forming step in the wafer processing method according to the present invention, as shown in FIG. 11, the first spindle unit 64a is placed in a plane parallel to the holding surface 34a of the chuck table 34 (a plane parallel to the paper surface). (Inner) Inclined with respect to the index feed direction indicated by arrow Y. As a result, the cutting direction of the first cutting blade 643a attached to the first rotating spindle 642a constituting the first spindle unit 64a (direction perpendicular to the axis of the rotating spindle 642a) is indicated by an arrow X. It will be in the state where it inclined with respect to the cutting feed direction shown, ie, division division line 11. Then, the lower end B at the outer peripheral edge of the first cutting blade 643 a is positioned at a position corresponding to the center position in the width direction of the division line 11 of the semiconductor wafer 10 held by the chuck table 34. Next, the first cutting blade 643a is cut and fed by a predetermined amount and rotated in the direction indicated by the arrow A. Then, the chuck table 34 holding the semiconductor wafer 10 is cut and fed in the cutting feed direction indicated by the arrow X (leftward in FIG. 11). As a result, a shallow groove G1 corresponding to the planned division line 11 is formed as shown in FIG. Thus, even if the first cutting blade 414a is worn as shown in FIG. 10, the cutting direction of the first cutting blade 643a mounted on the first rotating spindle 642a (on the axis of the rotating spindle 642a). The shallow groove G1 corresponding to the planned dividing line 11 can be formed by performing the shallow groove forming process in a state where the direction perpendicular to the planned dividing line 11 is inclined. Therefore, the cutting blade to be discarded can be used effectively by carrying out the processing method according to the present invention, which is economical.

  As described above, if the shallow groove G1 corresponding to the division line 11 is formed as shown in FIG. 12 by performing the shallow groove forming process by the worn first cutting blade 643a as shown in FIG. The above-described processing steps are performed by the second cutting blade 643b. As a result, as shown in FIG. 13, a cutting groove G2 reaching the dicing tape T is formed along the shallow groove G1 formed corresponding to the division line 11 and the semiconductor wafer 10 is cut along the division line 11. Is done.

In the above-described embodiment, the example in which the shallow groove forming step according to the present invention is performed when the first cutting blade 643a having a thickness corresponding to the division line 11 is worn is shown. Even if there is no cutting blade having a thickness corresponding to the above, a shallow groove having a desired width is formed along the division line 11 by performing the shallow groove forming step according to the present invention using the cutting blade for cutting. I'm going.
In the above-described embodiment, the shallow groove forming step is performed, and the processing step for performing processing along the shallow grooves G1 formed corresponding to the division lines 11 is performed using the second cutting blade 643b. Although an example is shown, in the processing step, the semiconductor wafer 10 may be divided into individual devices by irradiating a laser beam along the shallow groove G1 formed corresponding to the division line 11.
Further, in the above-described embodiment, the example in which the wafer processing method according to the present invention is implemented using the cutting apparatus 1 including the first cutting means 5a and the second cutting means 5b is shown. The wafer processing method according to (1) can be carried out using a cutting apparatus provided with only the first cutting means.

1: Cutting device 2: Stationary base 3: Chuck table mechanism 34: Chuck table 36: Cutting feed means 5a: First cutting means 5b: Second cutting means 51a: First indexing movement base 51b: Second Index movement base 52a: first cutting movement base 52b: second cutting movement base 53a: first spindle unit support member 53b: second spindle unit support member 64a: first spindle unit 642a: First rotating spindle 643a: first cutting blade 64b: second spindle unit 642b: second rotating spindle 643b: second cutting blade 10: semiconductor wafer

Claims (2)

A wafer processing method in which a device is formed in an area defined by a plurality of division lines on the surface,
A shallow groove forming step of forming a shallow groove having a desired width along the line to be divided by a cutting blade attached to the rotary shaft;
Processing along the shallow groove of the wafer on which the shallow groove forming step has been performed, and
The shallow groove forming step forms a shallow groove having a desired width by cutting along the planned dividing line in a state where the rotation axis is inclined so that the cutting direction of the cutting blade is inclined with respect to the planned dividing line.
A method for processing a wafer.   2. The wafer processing method according to claim 1, wherein in the processing step, the wafer is cut along a shallow groove formed along a planned division line and divided into individual devices.

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