JP2006245493A - Semiconductor wafer electrode processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize a cutting tool and to prolong lifetime thereof by suppressing partial abrasion of the cutting tool to approximately uniform abrasion condition when the head of a bump of the surface of a semiconductor wafer is chipped off by the cutting tool such as a cutter to uniform the height. <P>SOLUTION: The semiconductor wafer W held on a chuck table 17 in such a state that it is not rotated is sent to a cutting unit 20 in which the cutter 26 rotates, and made to reciprocate to make the cutter 26 act to the semiconductor wafer W in both the processes of sending on an approach route (a first cutting process) and that on a return route (a second cutting process). Thereby the process of abrasion of left and right cutting edges 28a and 28b in a cutting part 28 of the cutter 26 is equalized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrode processing method for removing the tips of a plurality of electrodes protruding from the surface of a semiconductor wafer so as to align the height.

  A semiconductor chip having an electronic circuit such as an IC or LSI formed on its surface is now indispensable for downsizing various electric / electronic devices. A semiconductor chip is a process in which a rectangular region of a lattice shape is defined by cutting lines called streets on the surface of a disk-shaped semiconductor wafer, an electronic circuit is formed in these rectangular regions, and then the semiconductor wafer is divided along the streets. Manufactured by.

  By the way, in recent years, in order to enable further miniaturization of electric / electronic devices, bumps having a height of about 15 to 100 μm are formed as electrodes on the surface of the semiconductor chip, and this bump is mounted on the mounting substrate. A semiconductor chip called a flip chip has been developed and put into practical use so as to be directly bonded to the electrode formed on the substrate. In addition, a technique for reducing the size by mounting or stacking a plurality of semiconductor chips on a substrate called an interposer has been developed and put into practical use.

  In any of the above technologies, the substrates are bonded together by bonding via a plurality of bumps formed on the surface of the device. Must be uniform.

  Therefore, it is necessary to process the bumps to the same height. As a processing method, the tip of the electrode is removed by CMP using a chemical on the semiconductor wafer, or the tip is ground with a grinding tool. Such a method was common. However, the former method has the disadvantages that the processing time is long and the workability is inferior. In the latter method, when the bump is a metal having a relatively high viscosity such as gold, burrs are generated because the grindability is poor. There is a drawback in that the burr contacts with the adjacent bump and short-circuits.

  Further, as a method of forming a bump, there is a stud bump method in which molten metal particles such as gold are attached to an electrode formed on the surface of a semiconductor wafer, and a neck portion protruding from a granular portion to be an electrode is broken to obtain a bump. . However, the bump formed thereby is difficult to polish because the needle-like or thread-like traces remain at the tip when the neck is broken as described above. For this reason, a heated plate is pressed against the tip of the bump. The height is made uniform (see Patent Document 1).

  However, even if the bump heights were made uniform in this way, there was a problem that adjacent bumps were short-circuited. In view of this, the present applicant has proposed a processing apparatus that removes the tip of the bump protruding from the surface of the semiconductor wafer with a cutting tool such as a cutting tool so that the height is uniform (Patent Document 2).

JP 2001-53097 A JP 2004-319697 A

  As described in Patent Document 2, the method of removing the bumps on the surface of the semiconductor wafer by using a cutting tool has an advantage that the height can be easily adjusted without causing a short circuit. In this method, the cutting edge of the bump is cut by relatively moving the cutting edge of the cutting tool by stroking the surface from the outer peripheral edge to the inner peripheral side of the semiconductor wafer, and the cutting is completed by cutting only in one direction. I am letting. For this reason, only one side which hits the bump of the cutting edge of the cutting tool is worn out. When the cutting edge is worn so that it cannot be used, the cutting tool is discarded even though the other side can be used. Therefore, it cannot be said that the byte is used efficiently, which is uneconomical, and this is a problem.

  Therefore, in the present invention, when cutting the tip of the bump on the surface of the semiconductor wafer with a cutting tool such as a cutting tool to align the height, uneven wear of the cutting tool can be suppressed and the wear state can be made almost uniform. It is an object of the present invention to provide a method for processing an electrode of a semiconductor wafer that can effectively use a cutting tool and prolong its life.

  The present invention relates to a cutting means provided with a cutting tool, a chuck table for holding a disk-shaped semiconductor wafer, a processing position for processing the semiconductor wafer by the cutting means, and a semiconductor wafer to the chuck table. A chuck using an electrode processing apparatus comprising: a chuck table moving means positioned at an attaching / detaching position to be attached / detached; and a machining feed means for bringing a cutting tool of the cutting means closer to or away from the chuck table positioned at the machining position. A semiconductor wafer electrode processing method in which the tips of a plurality of electrodes projecting on the surface of a semiconductor wafer held on a table are scraped with a cutting tool to make the height uniform, and a semiconductor that holds a semiconductor wafer on a chuck table at an attachment / detachment position A combination of a cutting tool and a semiconductor wafer at the wafer holding process and the processing position. A first cutting step of cutting the tip of the electrode with a cutting tool while the forward tool is fed forward, and the cutting tool and the semiconductor wafer are relatively fed back after the first cutting step, thereby cutting the cutting tool. And a second cutting step of cutting the tip of the electrode.

  According to the present invention, by performing the first and second cutting steps, the cutting tool cuts the electrode while reciprocating relative to the semiconductor wafer. For this reason, a cutting tool that has been worn only on one side because it was only forward feed in the prior art will wear on the other side as well by being subjected to a return feed cutting process, so that it will wear almost evenly. . Further, by performing the finishing process by the backward feed, it is possible to save the trouble of performing the finishing after returning the cutting tool to the cutting start position, thereby shortening the machining time and improving the production efficiency.

  In order to relatively reciprocate the cutting tool and the semiconductor wafer, the chuck table holding the semiconductor wafer may be reciprocated at the processing position by the chuck table moving means. That is, the first and second cutting steps are performed by moving the semiconductor wafer back and forth with respect to the cutting tool without moving the cutting tool.

  The cutting means of the present invention includes a type in which the cutting tool rotates and a type in which the cutting tool does not rotate. The reciprocating operation differs depending on this difference. When the cutting tool rotates, the cutting means has a rotation drive unit that rotates the cutting tool. As a cutting method, a semiconductor wafer held on a chuck table is opposed to a rotating cutting tool in a non-rotating state, and the diameter from one end to the other end of the outer peripheral edge of the semiconductor wafer is a first cutting step. The cutting tool is caused to act over the diameter of the semiconductor wafer from the other end to the one end as the second cutting step. Thereby, the cutting tool can be applied to the entire surface of the semiconductor wafer.

  On the other hand, when the cutting tool does not rotate, the cutting means supports the cutting tool in a fixed state. As a cutting method, a semiconductor wafer held on a chuck table is opposed to a non-rotating cutting tool in a rotated state, and cutting is performed over a radius from the outer peripheral edge of the semiconductor wafer to the center of rotation as a first cutting step. The tool is applied, and the cutting tool is applied over a radius extending from the rotation center of the semiconductor wafer to the outer peripheral edge as the second cutting step. Thereby, the cutting tool can be applied to the entire surface of the semiconductor wafer.

  According to the present invention, when cutting the tip of the bump on the surface of the semiconductor wafer to make the height uniform, the cutting tool is reciprocated relative to the semiconductor wafer to perform cutting in both the forward feed and the backward feed. By causing the tool to act on the semiconductor wafer, uneven wear of the cutting tool can be suppressed and the wear state can be made substantially uniform. As a result, it is possible to effectively use the cutting tool and prolong the service life.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[1] Apparatus Configuration FIG. 1 shows an entire electrode processing apparatus A that can suitably carry out the electrode processing method of the present invention. FIG. 2 shows a disk-shaped semiconductor wafer W processed by the apparatus A. Show.

  As shown in FIG. 2A, the semiconductor wafer W has a plurality of semiconductor chips 1 formed in a lattice shape on the surface. Each semiconductor chip 1 is formed with a plurality of bumps (electrodes) 2 as shown in FIG. The bump 2 is bonded to the electrode of the electronic circuit formed on the semiconductor chip 1 and protrudes from the surface of the semiconductor wafer W. These bumps 2 are formed by, for example, a well-known stud bump forming method, and the heights are often uneven. The electrode processing apparatus A performs processing on the semiconductor wafer W by scraping off the tips of all the bumps 2 protruding from the surface of one semiconductor wafer W so as to make the height uniform.

  As shown in FIG. 1, the electrode processing apparatus A includes a base 10 on which various mechanisms are mounted. The base 10 is installed in a horizontally long state and is a rectangular parallelepiped table 11 which is the main body of the base 10, and a longitudinal end of the table 11 (end on the back side in FIG. 1) And a wall portion 12 extending in the width direction and vertically upward. In FIG. 1, the longitudinal direction, the width direction, and the vertical direction of the base 10 are shown as a Y direction, an X direction, and a Z direction, respectively.

On the table 11 of the base 10, the wall 12 side from the substantially middle part in the longitudinal direction is a processing area 11A, and the opposite side supplies the semiconductor wafer W before processing to the processing area 11A, and the processed semiconductor. A supply / recovery area 11B for collecting the wafer W is used.
Hereinafter, various mechanisms provided in the electrode processing apparatus A will be described separately for those provided in the processing area 11A and those provided in the supply / recovery area 11B.

(A) Mechanism of processing area 11A As shown in FIG. 1, a rectangular recess 13 is formed in the processing area 11A, and a rectangular stage (chuck table moving means) is formed on the bottom surface of the recess 13. ) 14 is provided to be movable in the Y direction. The table 11 is slidably attached to a guide rail disposed in the stage 14 and extending in the Y direction, and is reciprocated in the same direction by an appropriate drive mechanism (none of which is shown).

  One end of bellows 15 and 16 is attached to both ends of the stage 14 in the moving direction, and the other end of these bellows 15 and 16 is the inner surface of the wall portion 12 and the recess 13 facing the wall portion 12. Are attached to the inner wall surface of each. These bellows 15, 16 cover a slit (not shown) formed on the bottom surface of the recess 13 in order to connect the stage 14 to the guide rail, and prevent cutting chips and the like from falling into the stage 14. Thus, the stage 14 expands and contracts with the movement of the stage 14 and does not hinder the movement.

  On the stage 14, a disk-shaped chuck table 17 having a Z-direction as a rotation center and a horizontal upper surface is rotatably provided. The semiconductor wafer W is placed concentrically and horizontally on the chuck table 17 with the surface on which the bumps 2 are formed facing upward. The chuck table 17 is rotated in one direction or both directions by a rotation drive mechanism (not shown) provided in the stage 14. Since the cutting unit 20 described later in the present embodiment is a type that rotates a cutting tool 26 that is a cutting tool, the chuck table 17 that holds the semiconductor wafer W may not be freely rotatable but may be fixed.

  In this case, the chuck system of the chuck table 17 is a known vacuum chuck. That is, as shown in FIG. 3A, the chuck table 17 in this case has a plurality of grooves 17a formed concentrically and at equal intervals on the surface. As shown in FIG. 3 (b), an air suction passage 17b that communicates with each groove 17a and opens to the back surface side is formed. An air suction port of a vacuum device (not shown) is connected to the opening on the back side of the air suction passage 17b. When the vacuum device is operated, the semiconductor wafer W is attracted and held on the chuck table 17. ing.

  When the chuck table 17 moves to the wall 12 side, the chuck table 17 is positioned at a machining position, and a cutting unit (cutting means) 20 is disposed above the machining position. The cutting unit 20 is supported on the wall 12 of the base 10 via a feed mechanism (process feed means) 30 so as to be movable up and down in the Z direction. The feed mechanism 30 includes a pair of guide rails 31 that are fixed to the inner surface of the wall portion 12 that is a vertical surface and that extend in the Z direction, and a slider 32 that is slidably attached to the guide rails 31. And a slider drive mechanism 33 that reciprocates the slider 32 along the guide rail 31.

  The slider drive mechanism 33 is arranged in the space between the slider 32 and the wall portion 12 with the axial direction being parallel to the Z direction, and the upper end portion and the lower end portion are bearings 34 and 35 provided on the wall portion 12, respectively. And a pulse motor 37 that rotationally drives the screw rod 36. The screw rod 36 is threadedly engaged with a bracket (not shown) formed on the back surface of the slider 32 so as to pass therethrough. Thus, the slider 32 moves downward (feed direction) when the pulse motor 37 rotates forward and the screw rod 36 rotates in one direction, and the pulse motor 37 reverses and the screw rod 36 moves in the reverse direction. When rotated, it moves upward (withdrawal direction).

  The cutting unit 20 has a block 21 fixed to the front surface of the slider 32 facing the table 11 side, and a cylindrical shape that is passed through the block 21 so that the axial direction is along the Z direction, and is fixed to the block 21. , A rotating shaft (rotation drive unit) 23 supported concentrically and rotatably in the housing 22, a servo motor 24 that rotationally drives the rotation shaft 23, and a downward projection from the housing 22. A disk-shaped wheel mount 25 concentrically fixed to the lower end of the rotary shaft 23 and a cutting tool (cutting tool) 26 detachably attached to the wheel mount 25 are provided. In this case, the rotating shaft 23 and the wheel mount 25 are rotated by the servo motor 24 in the direction of the arrow (described on the upper surface of the wheel mount 25) in FIG.

  As shown in FIG. 4, the cutting tool 26 has a blade 28 made of diamond or the like fixed to the tip of a shank 27. As shown in FIG. 4B, the blade portion 28 has a bilaterally symmetric shape and cuts a workpiece with a blade edge formed in an arc shape. The cutting tool 26 is arranged with the shank 27 in a state where the blade portion 28 is disposed below and the cutting direction of the blade portion 28 (the arrow direction in FIG. 4A) is directed to the rotation direction of the wheel mount 25. Is inserted into the mounting hole 25a formed from below. And the insertion state is being fixed with the volt | bolt 29 screwed in toward the attachment hole 25a from the outer peripheral surface of the wheel mount 25. FIG. As a result, the cutting tool 26 is fixed so as to protrude downward from the outer periphery of the wheel mount 25.

  As shown in FIG. 5, the outer diameter of the wheel mount 25 is about 1.5 times the diameter of the semiconductor wafer W, but the dimensions are not limited to this. However, the rotation trajectory of the cutting tool 26 based on the mounting position on the wheel mount 25 is set to a size capable of processing the entire surface of the semiconductor wafer W. Further, in the chuck table 17 and the cutting unit 20, a line connecting the rotation center of the semiconductor wafer W concentrically held on the chuck table 17 and the rotation center of the wheel mount 25 is in a state along the Y direction. It is positioned as follows.

(B) Mechanism of Supply / Recovery Area 11B As shown in FIG. 1, the supply / recovery area 11B set on the table 11 of the base 10 has a rectangular shape that is narrower and deeper than the recess 13. A recess 18 is formed, and a transfer mechanism 60 in which a fork 60b is attached to the tip of a two-joint link-type horizontal swivel arm 60a that can be moved up and down is installed at the bottom of the recess 18.

  Then, on the table 11 around the recess 18, the suction plate 63 b is attached to the tip of the cassette 61, the alignment table 62, and the horizontal turning arm 63 a of the first node in a counterclockwise direction as viewed from above. The recovery arm 64 having the same structure as the supply arm 63 and the supply arm 63, the horizontal turning arm 64a and the suction plate 64b, the spinner type cleaning device 65, and the cassette 66 are arranged.

  The cassette 61, the alignment table 62, and the supply arm 63 are means for supplying the semiconductor wafer W to the chuck table 17. The recovery arm 64, the cleaning device 65, and the cassette 66 allow the processed semiconductor wafer W to be transferred from the chuck table 17. It is a means to collect. Although the two cassettes 61 and 66 have the same structure, they will be referred to as a supply cassette 61 and a recovery cassette 66 according to applications. These cassettes 61 and 66 are for accommodating and carrying a plurality of semiconductor wafers W, and are set at predetermined positions on the table 11.

  A plurality of semiconductor wafers W whose bumps 2 are to be processed by the electrode processing apparatus A are accommodated in the supply cassette 61 in a stacked state. The transfer mechanism 60 takes out one semiconductor wafer W from the supply cassette 61 by raising / lowering and turning the arm 60a and gripping the fork 60b, and further removes the semiconductor wafer W on the surface on which the bumps 2 are formed. It has a function of being placed on the alignment table 62 in a state of facing upward.

  The semiconductor wafer W placed on the alignment table 62 is placed in a state determined at a certain position. The supply arm 63 sucks the semiconductor wafer W placed on the alignment table 62 onto the suction plate 63b, rotates the arm 63a, and places the semiconductor wafer W on the chuck table 17, and then performs a suction operation. By stopping the semiconductor wafer W, the semiconductor wafer W is placed on the chuck table 17. By placing the semiconductor wafer W positioned by the alignment table 62 on the chuck table 17 at the supply / recovery position, the semiconductor wafer W and the chuck table 17 are concentric.

  The recovery arm 64 sucks the semiconductor wafer W on the chuck table 17 on which the bumps 2 are processed by the cutting unit 20 to the suction plate 64b, and rotates the arm 64a to transfer the semiconductor wafer W into the cleaning device 65. It has a function. The cleaning device 65 has a function of rotating the semiconductor wafer W to shake off and remove moisture after the semiconductor wafer W is washed with water. The semiconductor wafer W cleaned by the cleaning device 65 is transferred and accommodated in the collection cassette 66 by the transfer mechanism 60.

  A chuck table cleaning nozzle 67 for cleaning the chuck table 17 by spraying high-pressure air onto the chuck table 17 is disposed between the supply arm 63 and the recovery arm 64. As described above, when the semiconductor wafer W is placed on the chuck table 17 by the supply arm 63 and the semiconductor wafer W on the chuck table 17 is recovered by the recovery arm 64, that is, the semiconductor wafer is mounted on the chuck table 17. When detaching W, the stage 14 is moved to the supply / collection area 11B side and stopped at the supply / collection position. The supply / recovery position is a position where the line connecting the center of the semiconductor wafer W sucked by the suction plates 63b and 64b of the arms 63 and 64 and the rotation center of the chuck table 17 is along the Z direction.

  The processing position of the semiconductor wafer W by the cutting unit 20 is a range moved by a predetermined distance from the supply / recovery position toward the wall 12, and the semiconductor wafer W on the chuck table 17 is moved to the processing position by the movement of the stage 14. And the supply / recovery position. The chuck table 17 is cleaned by the chuck table cleaning nozzle 67 at the supply / recovery position.

[2] Operation of the apparatus Next, the usage method and operation of the electrode processing apparatus A having the above configuration will be described below. The operation described here is a specific example of the processing method of the present invention.
The operator prepares for processing by setting a supply cassette 61 containing a plurality of semiconductor wafers W for processing the bumps 2 and an empty recovery cassette 66 at predetermined positions in the supply / recovery area 11B.

  Subsequently, one semiconductor wafer W is taken out from the supply cassette 61 by the transfer mechanism 60, and the semiconductor wafer W is further placed on the alignment table 62 with the back surface facing up by the transfer mechanism 60. Is done.

  Next, the semiconductor wafer W placed on the alignment table 62 is placed concentrically by the supply arm 63 on the chuck table 17 previously stopped at the supply / recovery position with the surface facing up. The Then, the semiconductor wafer W is sucked and held on the chuck table 17 by a vacuum device (semiconductor wafer holding step).

  Next, the vertical position of the cutting unit 20 is adjusted by the feeding mechanism 30 so that the cutting tool 26 can cut the bump 2 to a predetermined height, and the wheel mount 25 is rotated by the servo motor 24. From this state, the stage 14 is moved to the cutting unit 20 side, and the semiconductor wafer W held on the chuck table 17 in a fixed state is sent to a processing position below the cutting unit 20 at a predetermined speed. Go (outward feed: first cutting step).

  FIG. 6A schematically shows the first cutting step, and the cutting edge of the blade portion 28 of the cutting tool 26 in this first step is sent as shown in FIG. 6B. One side 28a side (supply / recovery position side) opposite to the semiconductor wafer W tends to act on the bumps 2 and wear.

  In the first cutting process, the tips of the bumps 2 on the surface of the semiconductor wafer W are scraped off by the blade portion 28 of the cutting tool 26. As shown in FIG. 5, the bite extends until the semiconductor wafer W is covered with the wheel mount 25, that is, over the diameter from the one end on the wall 12 side to the other end on the supply / recovery position side of the outer peripheral edge of the semiconductor wafer W. When the 26 blade portions 28 act to cut the entire surface of the semiconductor wafer W, the first cutting process is finished.

  Subsequently, the cutting unit 20 is slightly lowered by the feed mechanism 30, and the position of the cutting tool 26 is adjusted to the height of the finishing process. Then, with the operation of the cutting unit 20 continued, the stage 14 is now returned to the supply / recovery position (return feed: second cutting step).

  FIG. 7A schematically shows the second cutting step, and the cutting edge of the blade portion 28 of the cutting tool 26 in this second step is a returning semiconductor as shown in FIG. 7B. The one surface 28b side (the wall portion 12 side), which is the side facing the wafer W, tends to act on the bumps 2 and wear.

  When the outer peripheral edge of the semiconductor wafer W extends from the other end on the supply / recovery position side to the one end on the wall 12 side, the blade portion 28 of the cutting tool 26 acts, and the finishing process on the entire surface of the semiconductor wafer W is completed. The second cutting process is finished.

  In the present embodiment, the entire surface is processed by reciprocating in the Y direction a semiconductor wafer W that is not rotating because the chuck table 17 is fixed to the rotating bit 26. The saw mark, which is a cutting pattern of the cutting tool 26, looks like the semiconductor wafer W shown on the right side of FIG.

  Through the first and second cutting processes described above, the bumps 2 on the surface of the semiconductor wafer W are scraped off by the blade portions 28 of the cutting tool 26, and the heights of all the bumps 2 are made uniform. Here, the processing is completed, the cutting unit 20 is raised, and the rotation of the wheel mount 25 is stopped.

  As an example of suitable operating conditions in the above cutting, the cutting allowance of the cutting tool 26 in the first cutting process (the depth of cutting from the tip of the bump 2) is 8 μm, and the cutting allowance in the second cutting process is 2 μm. In any cutting process, the rotation speed of the cutting tool 26 by the servo motor 24 is about 2000 RPM, and the feeding speed of the semiconductor wafer W by the movement of the stage 14 is 0.5 to 0.7 mm / second.

  Next, the operation of recovering the processed semiconductor wafer W with the bumps 2 of the same height will be described. First, the stage 14 is moved to the supply / recovery position, and the operation of the vacuum device is stopped. The holding state of the semiconductor wafer W on 17 is released. Next, the semiconductor wafer W is transferred into the cleaning device 65 by the recovery arm 64. Here, the semiconductor wafer W is washed with water and then rotated to remove moisture.

  Next, the semiconductor wafer W is transferred and accommodated in the collection cassette 66 by the transfer mechanism 60. Further, after the semiconductor wafer W is removed from the chuck table 17 by the recovery arm 64, high-pressure air is directed from the chuck table cleaning nozzle 67 toward the chuck table 17 on the stage 14 stopped at the supply / recovery position. The chuck table 17 is cleaned by spraying.

  The above is the cycle in which the tip of the bump 2 is cut on one semiconductor wafer W, and then washed and collected. When this cycle is repeated and all the semiconductor wafers W in the supply cassette 61 are processed and accommodated in the recovery cassette 66, the operator recovers the recovery cassette 66 and continues the plurality of processed semiconductor wafers W. To the product manufacturing process. Then, a supply cassette 61 containing a plurality of new semiconductor wafers W for processing the bumps 2 and an empty recovery cassette 66 are set at predetermined positions in the supply / recovery area 11B, and the cutting process is continued in the above cycle. Do. Note that the empty supply cassette 61 may be used as the recovery cassette 66.

  Prior to cutting the bumps 2 of the semiconductor wafer W as described above, in order to make the distance between the cutting edge of the cutting tool 26 and the upper surface of the chuck table 17 uniform, the upper surface of the chuck table 17 is placed on the cutting unit 20 itself. In some cases, self-cutting may be performed. Also in the case of this self-cutting, the cutting tool 26 may be reciprocated over the diameter of the chuck table 17 and the surface thereof may be cut with the cutting tool 26 as described above.

[3] Effect According to the bump 2 processing method using the electrode processing apparatus A of the present embodiment, the semiconductor wafer W is reciprocated with respect to the cutting tool 26 of the cutting unit 20, and the tip of the bump 2 is moved in the process. It is cut off and the height is aligned. Therefore, the cutting edge of the cutting tool 26 that has worn only on one side (indicated by 28a in FIG. 6B in the present embodiment) because only the forward feeding is conventionally used can be changed by adding a backward feeding cutting process. Since one side (28b) also acts on cutting, it will be worn almost evenly. As a result, the byte 26 can be used effectively and its life can be extended.

  Further, by performing the finishing process by the backward feed, it is possible to save the trouble of performing the finishing after returning the cutting tool 26 to the cutting start position, thereby shortening the machining time and improving the production efficiency.

[4] Another Form of Cutting Unit FIG. 8 shows another form of the cutting unit. The cutting unit 70 in this case includes a block 71 fixed to the front surface of the slider 32 of the feed mechanism 30 and a cutting tool 26 detachably fixed to the block 71. The cutting tool 26 is inserted into a mounting hole 71 a formed at the tip of the block 71 on the side opposite to the slider in the same manner as in the above embodiment, and is fixed by a bolt 29.

  When the cutting unit 70 is used, the stage 14 is moved toward the cutting unit 20 while rotating the chuck table 17, the semiconductor wafer W rotating together with the chuck table 17 is sent to the processing position, and the bump 26 is bumped by the fixed bit 26. The tip of 2 is cut (outward feed: first cutting step). In the first cutting step, as shown in FIG. 9, the cutting tool 26 is applied to the bump 2 over a radius from the outer peripheral edge of the semiconductor wafer W to the rotation center.

  Next, after the cutting tool 26 is adjusted to a finishing height, the cutting tool 26 is applied over the radius from the rotation center of the semiconductor wafer W to the outer peripheral edge to cut the bump 2 (return feed: second cutting step). ).

  Through the first and second cutting processes described above, the bumps 2 on the surface of the semiconductor wafer W are scraped off by the blade portions 28 of the cutting tool 26, and the heights of all the bumps 2 are made uniform.

  In this embodiment, the entire surface is processed by reciprocating the semiconductor wafer W rotated by the chuck table 17 with respect to the fixed bit 26 in the Y direction. The saw mark which is the cutting pattern of the cutting tool 26 in this case is a semiconductor wafer W shown on the right side of FIG.

It is a whole perspective view of the electrode processing apparatus which can implement suitably the method of the present invention. FIG. 2A is an overall perspective view of a semiconductor wafer on which bumps are processed by the electrode processing apparatus shown in FIG. 1, and FIG. 2B is a plan view of a semiconductor chip formed on the semiconductor wafer. It is (a) perspective view of the chuck table with which the electrode processing apparatus shown in FIG. 1 is equipped, (b) It is a partial cross section figure. It is the (a) side view of the cutting tool of the cutting unit with which the electrode processing apparatus shown in FIG. 1 is equipped, (b) It is a front view. It is a top view which shows the positional relationship between the wheel mount of a cutting unit, and the semiconductor wafer hold | maintained at a chuck table, and the saw mark of a semiconductor wafer. (A) is a figure which shows a 1st cutting process typically, (b) is a figure which shows the abrasion state of the blade edge | tip of the cutting tool in the same process. (A) is a figure which shows a 2nd cutting process typically, (b) is a figure which shows the abrasion state of the blade edge | tip of the cutting tool in the same process. It is a perspective view which shows another form of a cutting unit. FIG. 9 is a plan view showing a positional relationship between the cutting unit shown in FIG. 8 and a semiconductor wafer held on a chuck table, and saw marks of the semiconductor wafer.

Explanation of symbols

1 ... Semiconductor chip 2 ... Bump (electrode)
14 ... Stage (chuck table moving means)
17 ... Chuck table 20, 70 ... Cutting unit (cutting means)
23... Rotating shaft (rotation drive unit)
26 ... Bite (cutting tool)
30 ... Feeding mechanism (processing feed means)
A ... Electrode processing equipment W ... Semiconductor wafer

Claims (4)

A cutting means equipped with a cutting tool;
A chuck table for holding a disk-shaped semiconductor wafer;
A chuck table moving means for positioning the chuck table at a processing position for processing the semiconductor wafer by the cutting means and an attaching / detaching position for attaching / detaching the semiconductor wafer to / from the chuck table;
Using an electrode processing apparatus provided with a processing feed means for moving the cutting tool of the cutting means closer to or away from the chuck table positioned at the processing position,
An electrode processing method for a semiconductor wafer, in which tips of a plurality of electrodes protruding on the surface of the semiconductor wafer held on the chuck table are scraped with the cutting tool to have a uniform height,
A semiconductor wafer holding step for holding the semiconductor wafer on the chuck table at the attachment / detachment position;
A first cutting step of cutting the tip of the electrode with a cutting tool while relatively feeding the cutting tool and the semiconductor wafer in the processing position;
After the first cutting step, the semiconductor wafer is provided with a second cutting step in which the cutting tool and the semiconductor wafer are relatively fed backward to cut the tip of the electrode with the cutting tool. Electrode processing method.   2. The semiconductor wafer according to claim 1, wherein the reciprocating feed between the cutting tool and the semiconductor wafer in the first cutting step and the second cutting step is performed by the chuck table moving means. Electrode processing method. The cutting means has a rotation driving unit that rotates the cutting tool, and the cutting tool rotated by the rotation driving unit is opposed to the semiconductor wafer held on the chuck table in a non-rotating state.
As the first cutting step, the cutting tool is operated over a diameter from one end to the other end of the outer peripheral edge of the semiconductor wafer,
3. The semiconductor wafer electrode processing method according to claim 2, wherein, as the second cutting step, the cutting tool is operated over a diameter from the other end to the one end of the semiconductor wafer. The cutting means supports the cutting tool in a fixed state, and makes the semiconductor wafer held on the chuck table face the cutting tool in a rotated state,
As the first cutting step, the cutting tool is operated over a radius from the outer peripheral edge of the semiconductor wafer to the rotation center,
The semiconductor wafer electrode processing method according to claim 2, wherein, as the second cutting step, the cutting tool is applied over a radius from the rotation center to the outer peripheral edge.

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