JP4038277B2 - Work piece cleaving method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of separating a workpiece into pellets having a predetermined size and shape by cleaving the workpiece such as a semiconductor wafer or glass by irradiating it with a laser beam.
[0002]
[Prior art]
As a method of separating a workpiece such as a semiconductor wafer into individual pellets, a method of separating by breaking after scratching with a scriber, a method of separating by dicing with a dicing apparatus, and the like are practically used.
[0003]
However, in the case of separation by braking, there is a problem that the pellets are damaged in the braking, and in the case of separation by dicing, cutting waste (contamination) adheres and contaminates the surface of the workpiece. There's a problem. Therefore, a method of separating into pellets by a cleaving technique without such a problem has been attracting attention.
[0004]
For example, as shown in FIG. 7, there are streets S that are a plurality of linear regions arranged in a lattice pattern at predetermined intervals on the surface, and circuit patterns are formed in a number of rectangular regions partitioned by the streets S. In the applied semiconductor wafer W, for example, as shown in FIG. 8, scribe flaws are formed vertically and horizontally on the street S to form a scribe region 31, and a laser beam is irradiated on the scribe region 31, whereby a thermal shock is applied. The scribe area is cleaved.
[0005]
Such cleaving is performed, for example, in a state where the semiconductor wafer W disposed on the frame F is held on the chuck table 32 as shown in FIG. 9 via the tape T as shown in FIG. The chuck table 32 has a suction part 33 for sucking and holding the semiconductor wafer W by suction force and a holding part 34 for holding the frame F. When cleaving, the semiconductor wafer W is sucked as shown in FIG. At the same time, the frame F is fixed to the holding portion 34.
[0006]
Then, as shown in FIG. 11, a scribe flaw is formed on the surface of the semiconductor wafer W by the action of the scribe needle 36 protruding downward from the scribe means 35, and every time a scribe flaw is formed on one street S, the scribe flaw is formed. By moving the means 35 in the Y-axis direction by the street interval to similarly form scribe flaws, and further rotating the chuck table 32 by 90 degrees to perform the same operation, scribe areas are formed in the street S vertically and horizontally. The
[0007]
Then, as shown in FIG. 12, the laser beam irradiated from the laser beam irradiation means 37 and the scribe region are aligned in the Y-axis direction, and the chuck table 32 is moved in the X-axis direction, thereby moving the scribe region. The scribe region is cleaved by irradiation with a laser beam. Further, every time one street S is cleaved, the laser beam irradiation means 37 is moved by the street interval in the Y-axis direction to cleave similarly, and the chuck table 32 is further rotated by 90 degrees to cleave similarly. Thus, as shown in FIG. 13, the streets S are cut vertically and horizontally and separated into individual pellets.
[0008]
When the workpiece is separated by cleaving in this way, the pellets are not damaged as in the case of braking, and the cutting surface is not generated as in the case of dicing, so the surface of the workpiece is contaminated. There will be no problem.
[0009]
[Problems to be solved by the invention]
However, since cutting grooves are formed by cutting in the case of dicing, there are some gaps between the pellets after cutting, whereas grooves are not formed in the case of cleaving, so that after separation as shown in FIG. Also, the adjacent pellets P are in extremely close contact with each other.
[0010]
For this reason, if the tape T is bent as shown in FIG. 15 when it is conveyed as it is after the cleaving, the pellets P are rubbed together to cause chipping and cracking in the pellets. This causes a problem of lowering.
[0011]
Thus, in the case of separating the workpieces by cleaving, there is a problem to be solved by preventing the pellets from being deteriorated by preventing the pellets from rubbing against each other after cleaving.
[0012]
[Means for Solving the Problems]
As a specific means for solving the above-mentioned problems, the present invention provides a method for cleaving a workpiece that is held and held on a chuck table of a cleaving device by a workpiece held on a frame via a tape, A cleaving step of cleaving a workpiece at a predetermined interval, and a tape expanding convex ring inserted into a groove formed in a tape expanding concave ring detachably disposed on the outer periphery of the chuck table , and the cleaving step The workpiece cleaved by is expanded into a plurality of pellets to expand the tape held in close contact to widen the interval between the pellets , and the tape expansion convex ring is inserted into the groove remains at least from a transfer step of the tape extended concave ring removed from the chuck table, it conveys the pellets held in the frame through the tape wider interval in the extension step of Also provides a cleaving method of composed workpiece.
[ 0013 ]
According to the cleaving method configured in this manner, the interval between the pellets is expanded by expanding the tape, and the pellets are not rubbed with each other at the time of conveyance, so that the pellets are not chipped or cracked.
[ 0014 ]
DETAILED DESCRIPTION OF THE INVENTION
As an embodiment of the present invention, a case where a semiconductor wafer is cleaved and separated into pellets using the cleaving apparatus 10 shown in FIG. 1 will be described as an example.
[ 0015 ]
When the semiconductor wafer W is cleaved by the cleaving apparatus 10 shown in FIG. 1, the semiconductor wafer W is generally held in a frame F via a tape T used for dicing and is stored in a cassette 11 in a plurality of stages. .
[ 0016 ]
The semiconductor wafer W held on the frame F is unloaded from the cassette 11 by the unloading / unloading means 12, is attracted to the conveying means 13, and the conveying means 13 pivots to be conveyed and placed on the chuck table 14. Suction hold.
[ 0017 ]
As shown in FIG. 2, the chuck table 14 is generally composed of a main body portion 16 and a fixed portion 20 to which a tape expansion concave ring 17 described later is detachably fixed. The main body portion 16 is formed of, for example, a suction portion 19 that sucks the semiconductor wafer W by a suction force that is formed of a porous member and is supplied from a suction source (not shown), and two holding portions 21 that hold the frame F. As shown in FIG. 1, it is rotatably supported by the support table 15 and is driven to rotate by a motor (not shown) disposed below the support table 15.
[ 0018 ]
In the holding portion 21, a pair of guide rails 22 are disposed, and the slide portion 23 is slidable within a required range by being guided by the guide rails 22.
[ 0019 ]
Further, the holding unit 21 has a rotating unit 24 that can slide integrally with the slide unit 23 and can rotate at a required angle, and is provided between the lower surface of the rotating unit 24 and the upper surface of the slide unit 23. Thus, the frame F can be sandwiched. In addition, the frame F can be held by the slide of the slide portion 23 so as to appropriately correspond to the size of the frame F.
[ 0020 ]
The tape expansion concave ring 17 is detachably fixed to the fixed portion 20, and a groove portion 25 having a predetermined width and depth is formed on the upper surface side thereof. Further, when the tape expansion concave ring 17 is fixed to the fixed portion 20, the upper surface of the tape expansion concave ring 17 and the upper surface of the suction portion 19 are positioned on substantially the same plane.
[ 0021 ]
The tape expansion convex ring 18 is formed in a size and shape corresponding to the groove portion 25 of the tape expansion concave ring 17, and the tape T can be expanded by inserting the tape expansion convex ring 18 into the groove portion 25. . When the semiconductor wafer W is placed on the chuck table 14, the tape expansion convex ring 18 is removed.
[ 0022 ]
When the semiconductor wafer W to be cut is sucked and held by the chuck table 14 configured as described above, the tape expansion concave ring 17 can be confirmed through the transparent or translucent tape T as shown in FIG. is there. The frame F is fixed by the holding portion 21.
[ 0023 ]
When the semiconductor wafer W is held on the chuck table 14 as shown in FIG. 3, the chuck table 14 moves in the X-axis direction and is positioned directly below the alignment means 26 shown in FIG. A region to be cleaved is detected, and the region to be cleaved and the scribe needle 28 protruding downward from the scribe means 27 are aligned in the Y-axis direction. When the alignment is performed in this way, as shown in FIG. 4, the scribe means 27 is lowered, and the chuck table 14 is further moved in the X-axis direction, and is scribed on the surface of the semiconductor wafer W by the action of the scribe needle 28. Scratches are formed.
[ 0024 ]
When the chuck table 14 further moves in the X-axis direction, a laser beam is irradiated from the irradiation unit 30 of the laser beam irradiation means 29 to a region where the scribe flaw is formed (scribe region), and the scribe region is cleaved.
[ 0025 ]
In this way, every time cleaving is performed, the scribing means 27 and the laser beam irradiation means 29 are indexed and fed at predetermined intervals in the Y-axis direction, and the cleaving is performed after the chuck table 14 is further rotated 90 degrees. Then, as shown in FIG. 5, the semiconductor wafer W is vertically and horizontally divided into individual pellets P (a cutting process). Note that, as described in the related art, all the scribe regions may be formed first, and then cleaving may be performed.
[ 0026 ]
The pellet P after cleaving is in an extremely close contact state as shown in FIG. 14, and when the semiconductor wafer W held by the frame F is removed from the chuck table 14 and transported in this state, the pellets rub against each other. As a result, chipping and cracking are likely to occur. Therefore, in a state where the frame F is fixed by the holding portion 21, the suction force of the semiconductor wafer W by the suction portion 19 is released, and the tape expansion convex ring 18 is inserted into the groove portion 25 of the tape expansion concave ring 17.
[ 0027 ]
When the tape expansion convex ring 18 is thus inserted into the groove portion 25, the tape T stretched so as to cover the groove portion 25 is pushed by the tape expansion convex ring and enters the groove portion 25 as shown in an enlarged manner in FIG. The tape T is pulled between the inner surface of the groove 25 and the tape expansion convex ring 18 and the entire tape T is expanded (expansion process).
[ 0028 ]
When the tape T is expanded in this way, as shown in FIG. 6, it is held in a state where the interval between the pellets P held on the tape T is widened. When the pellet P is transported while being held on the tape T, the frame F is removed from the holding portion 21 and the tape expansion concave ring 18 is inserted into the groove portion 25 while being removed. The ring 17 is removed from the fixed portion 20. By carrying out like this, it can convey, with the tape T expanded, ie, the state where the space | interval of the pellets P expanded.
[ 0029 ]
In this way, by widening the interval between the pellets after cleaving, even when the tape T is bent during transportation, the pellets do not rub against each other as in the past, so that the pellets are chipped and cracked and the quality is improved. It will not be reduced.
[ 0030 ]
【The invention's effect】
As described above, according to the cleaving method according to the present invention, the interval between the pellets is expanded by expanding the tape, and the pellets do not rub against each other during transportation . The quality of the pellet is not degraded. In addition, the cleaving technique is further utilized.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a cleaving apparatus suitable for carrying out a cleaving method according to the present invention.
FIG. 2 is a perspective view showing a configuration of a chuck table mounted on the cleaving apparatus.
FIG. 3 is a perspective view showing a state in which a semiconductor wafer before cutting is held on the chuck table.
FIG. 4 is an explanatory view showing a state in which the semiconductor wafer held on the chuck table is cleaved.
FIG. 5 is a perspective view showing a cleaved semiconductor wafer.
FIG. 6 is an explanatory view showing a state in which the tape expansion convex ring is inserted into the tape expansion concave ring.
FIG. 7 is a plan view showing a surface of a semiconductor wafer held on a frame via a tape.
FIG. 8 is a plan view showing a state in which a scribe region is formed on the semiconductor wafer.
FIG. 9 is a perspective view showing a chuck table used for conventional cleaving.
FIG. 10 is a perspective view showing a state where a semiconductor wafer before being cut is held on the chuck table.
FIG. 11 is an explanatory diagram showing a state in which a scribe region is formed on the semiconductor wafer held on the chuck table.
FIG. 12 is an explanatory view showing a state in which the semiconductor wafer held on the chuck table is cleaved.
FIG. 13 is a perspective view showing a cleaved semiconductor wafer.
FIG. 14 is an explanatory view showing a pellet in a close contact state after cleaving.
FIG. 15 is an explanatory view showing a state of pellets when the tape is bent.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Cleaving device 11 ... Cassette 12 ... Carrying-in / out means 13 ... Conveying means 14 ... Chuck table 15 ... Support table 16 ... Main-body part 17 ... Tape expansion concave ring 18 ... Tape expansion convex ring 19 …… Suction part 20 …… Fixed part 21 …… Holding part 22 …… Guide rail 23 …… Slide part 24 …… Rotation part 25 …… Groove part 26 …… Alignment means 27 …… Scribe means 28 …… Scribe needle 29 …… Laser beam irradiation means 30 …… Irradiation part 31 …… Scribe area 32 …… Chuck table 33 …… Suction part 34 …… Holding part 35 …… Scribing means 36 …… Scribe needle 37 …… Laser beam irradiation means W …… Semiconductor wafer T …… Tape F …… Frame P …… Pellets

Claims (1)

A method of cleaving a workpiece that is held by a chuck table of a cleaving device and cleaved the workpiece held on the frame via a tape,
A cleaving step of cleaving the workpiece at a predetermined interval;
The tape expansion convex ring is inserted into a groove formed in the tape expansion concave ring detachably disposed on the outer periphery of the chuck table, and the workpiece cut by the cleaving step becomes a plurality of pellets and closely contacts An expansion process of expanding the tape held in a state to widen the interval between the pellets ;
The tape expansion concave ring is removed from the chuck table while the tape expansion convex ring is inserted into the groove, and the interval is widened in the expansion process, and the pellets held on the frame are conveyed via the tape. A workpiece cleaving method comprising at least a conveying step .

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