JP4306337B2 - Expanding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to an adhesive sheet expanding method and an expanding apparatus, and in particular, an adhesive sheet is expanded after dicing processing on a plate-like material mounted on a ring-shaped frame via an adhesive sheet and diced into individual chips. Thus, the present invention relates to an expanding method and an expanding apparatus for expanding an interval between individual chips.
[0002]
[Prior art]
In semiconductor manufacturing processes, etc., wafers that are plate-like products with semiconductor devices or electronic parts formed on their surfaces are subjected to electrical tests in the probing process, and then in the dicing process, individual chips (also referred to as dies or pellets). The individual chips are then die bonded to the component base in a die bonding process. After die bonding, resin molding is performed to complete a finished product such as a semiconductor device or an electronic component.
[0003]
After the probing process, as shown in FIG. 5, the back surface of the wafer is attached to an adhesive sheet S (also called a dicing sheet or dicing tape) S having a thickness of about 100 μm with an adhesive layer formed on one side, and a rigid ring. Is mounted on a frame F. In this state, the wafer W is conveyed in the dicing process, between the dicing process and the die bonding process, and in the die bonding process.
[0004]
In the dicing process, a dicing apparatus that cuts the wafer by inserting grinding grooves into the wafer W with a thin grindstone called a dicing blade is used. The dicing blade is obtained by electrodepositing fine diamond abrasive grains with Ni, and an extremely thin one having a thickness of about 10 μm to 30 μm is used.
[0005]
The dicing blade is rotated at a high speed of 30,000 to 60,000 rpm and cut into the wafer W to completely cut the wafer W (full cut). At this time, since the adhesive sheet S stuck on the back surface of the wafer W is cut only about 10 μm from the front surface, the wafer W is cut into individual chips T, but the individual chips T are separated. In other words, since the arrangement of the chips T is not collapsed, the wafer state is maintained as a whole.
[0006]
Further, without using a dicing blade, a laser beam having a focused point is irradiated inside the wafer W to form a modified region due to a multiphoton absorption phenomenon inside the wafer, and the wafer W is started from this modified region. Laser dicing has been proposed to cleave. Also in this laser dicing process, the wafer W is diced as shown in FIG. 5, so that the arrangement of the chips T does not collapse and the wafer state is maintained as a whole.
[0007]
Here, even after dicing and dividing into individual chips T in this way, an assembly of the chips T in which the arrangement of the chips T is not broken is also referred to as a wafer W for convenience.
[0008]
Thereafter, the wafer W is sent to a die bonding process. A die bonder is used in the die bonding process. In the die bonder, the wafer W is first placed on the expansion stage, and then the adhesive sheet S is expanded, so that the interval between the chips T is widened so that the chips T can be easily picked up.
[0009]
Next, the chip T is pushed up with a pusher from below, and the chip T is picked up with a collet from above, and the chip T is bonded to a predetermined position of the base.
[0010]
As described above, it has been conventionally performed to incorporate an expanding apparatus that spreads the adhesive sheet S into the die bonder and widens the distance between the chips T. Various improved inventions of this expanding apparatus have also been made (see, for example, Patent Document 1 and Patent Document 2).
[0011]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-23003
[Patent Document 2]
Japanese Patent Laid-Open No. 7-321070
[Problems to be solved by the invention]
In the above-described conventional technology, the wafer W mounted on the frame F through the adhesive sheet S is cut into individual chips T by a dicing blade, and then conveyed in the dicing apparatus as it is to be cleaned. Then, it was transported to the die bonder, and the inside of the die bonder was transported as it was.
[0014]
However, in recent years, in a semiconductor device such as an IC, in order to increase the number of chips formed per wafer W, the width of a processing region (also called a street) for dicing processing has become extremely narrow. Therefore, an extremely thin dicing blade having a thickness of about 10 μm to 15 μm has been used in the dicing process.
[0015]
In the wafer W diced by such an extremely thin dicing blade and the wafer W diced by the above-mentioned laser dicing, the interval between the chips T is extremely narrow. When transported in a mounted state, the edges of adjacent chips T come into contact with each other due to vibration during transportation, and the edge portion is chipped or microcracked. The problem of compromising the product's reliability occurred.
[0016]
For this reason, it has been required to expand immediately after dicing in a dicing apparatus and to convey the chips T with a wider interval. However, even when the conventional expanding method and the expanding method described in Patent Document 1 and Patent Document 2 described above were performed in the dicing apparatus, the expansion was performed when the application of tension to the pressure-sensitive adhesive sheet S was canceled. Since the pressure-sensitive adhesive sheet S contracted again, the wafer W could not be transferred together with the frame F.
[0017]
The present invention has been made in view of such circumstances, and even when a wafer having an extremely narrow distance between chips after dicing is used, the edges of adjacent chips are brought into contact with each other due to vibration during conveyance. An object of the present invention is to provide an adhesive sheet expanding method and an expanding device that can be transported frame by frame without occurrence of chipping, microcracks, or the like in the edge portion.
[0018]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a plate-like object mounted on a ring-shaped frame via an adhesive sheet and diced into individual chips, after dicing. In the expanding method in which the pressure-sensitive adhesive sheet is expanded and the interval between the individual chips is expanded, the expanded state of the pressure-sensitive adhesive sheet is maintained while the plate-like object is mounted on the frame after the expansion. The adhesive sheet is expanded by forming a convex portion on the adhesive sheet between the frame and the plate-like material, allowing the plate-like object to be conveyed for each frame while maintaining the distance between the chips. characterized in that for holding the expanded state of the pressure-sensitive adhesive sheet by welding or bonding the base portion of the projecting portion There.
[0019]
According to the first aspect of the present invention, since the expanded state of the adhesive sheet is maintained while the diced plate is mounted on the frame, the plate is removed from the frame while maintaining the distance between the chips. Can be transported every time. Therefore, even if the distance between chips is extremely narrow, the edges of adjacent chips do not come into contact with each other due to vibration during conveyance, and the edge portion will not be chipped or microcracked. .
[0021]
According to the first aspect of the present invention, a convex portion is formed on the pressure-sensitive adhesive sheet and expanded, and the base portion of the convex portion is welded or adhered to hold the expanded state, so that the plate-like object can be handled for each frame. .
[0022]
The invention according to claim 2 is characterized in that, in the invention according to claim 1 , ultrasonic welding is performed on a base portion of a convex portion formed on the pressure-sensitive adhesive sheet. According to invention of Claim 2 , since the base part of the convex part formed in the adhesive sheet is welded with an ultrasonic wave, local welding can be performed easily.
[0023]
The invention according to claim 3 is the invention according to claim 1 or 2 , wherein the expansion of the pressure-sensitive adhesive sheet is performed without removing the plate-like material from the dicing chuck stage after the dicing. It is characterized by.
[0024]
According to the invention of claim 3, since the plate-like object after dicing is expanded while being chucked on the chuck stage, the edges of adjacent chips contact each other due to vibration during the conveyance even in the conveyance in the dicing apparatus. Thus, no chipping or microcracking occurs at the edge portion.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the expanding method and the expanding apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In each figure, the same number or symbol is attached to the same member.
[0030]
FIG. 1 is a cross-sectional view illustrating a configuration of an expanding apparatus. The expanding apparatus 10 includes an XYθ table 11, a chuck stage 12, a frame chuck 13, a pressing member 14, a housing 15, an ultrasonic welding tool 16 as a welding tool, a pressing ring 17, and the like.
[0031]
The XYθ table 11 is moved in the XY direction in the figure by a driving device (not shown) and rotated by θ. A chuck stage 12 and a frame chuck 13 are attached to the XYθ table 11. A porous member 13A is embedded in the upper surface of the frame chuck 13 and is connected to the decompression pump 23 via the electromagnetic valve 21B and the regulator 22B so as to adsorb the frame F.
[0032]
Further, a porous member (not shown) is also embedded in the upper surface of the chuck stage 12 and connected to the decompression pump 23 via the electromagnetic valve 21C and the regulator 22C so as to adsorb the wafer W which is a plate-like object.
[0033]
Above the portion of the adhesive sheet S where the frame F and the wafer W are not attached, a ring-shaped housing 15 having an annular groove (space portion) 15A is disposed. The inner surface of the annular groove 15A is formed of a porous member 15B, and is connected to a decompression pump 23 via an electromagnetic valve 21A and a regulator 22A so as to decompress the inside of the groove 15A. The housing 15 is moved up and down by driving means (not shown) and clamped at the lower end.
[0034]
A ring-shaped pressing member 14 is provided facing the housing 15 with the adhesive sheet S interposed therebetween. The pressing member 14 is moved up and down by driving means (not shown), and is positioned so as to rise and be inserted into the groove 15 </ b> A of the housing 15. The upper end edge of the pressing member 14 is smoothly chamfered.
[0035]
An annular pressing ring 17 is provided inside the housing 15 and is moved up and down by driving means (not shown) so as to strongly press the chuck stage 12 when moved downward.
[0036]
On the outside of the housing 15, an ultrasonic welding tool 16 as a welding tool is disposed obliquely with the tip thereof facing the inlet of the groove 15 </ b> A of the housing 15. The ultrasonic welding tool 16 is moved in the axial direction by a driving means (not shown), and presses the object with the tip while oscillating ultrasonic waves.
[0037]
Next, an expanding method by the expanding apparatus 10 configured as described above will be described. FIG. 2 is a flowchart showing an embodiment of the expanding method of the present invention. The wafer W mounted on the frame F via the adhesive sheet S is placed on the chuck stage 12 and the frame chuck 13, the wafer W is adsorbed to the chuck stage 12 via the adhesive sheet S, and the frame F is attached to the adhesive sheet S. Via the frame chuck 13. In this state, the wafer W is diced into individual chips T.
[0038]
When expanding the adhesive sheet S, as shown in FIG. 2, first, the adsorption of the frame F is left as it is, and the electromagnetic valve 21C is operated to release only the adsorption of the chuck stage 12 (step S11).
[0039]
Next, the housing 15 is lowered and clamped at a position where the lower end contacts the adhesive sheet S (step S13). Next, the pressing member 14 is raised and brought into contact with the pressure-sensitive adhesive sheet S, and further raised, the pressure-sensitive adhesive sheet S is pushed up to form a convex portion in the groove 15 </ b> A of the housing 15. Thereby, the adhesive sheet S is expanded outward from the central portion, and the interval between the chips T attached to the adhesive sheet S is expanded (step S15).
[0040]
Here, the pressing ring 17 is lowered, and the adhesive sheet S is pressed and clamped between the upper surface of the chuck stage 12. As a result, the expanded state of the pressure-sensitive adhesive sheet S inside the holding ring 17 is maintained (step S17).
[0041]
FIG. 3 shows this state. The pressure-sensitive adhesive sheet S is pushed up by the pressing member 14, and an annular convex portion SA is formed in the annular groove of the housing 15. As a result, the adhesive sheet S is extended outward from the central portion, the interval between the individual chips T is expanded, and the expanded state is held by the pressing ring 17.
[0042]
Next, the electromagnetic valve 21A is actuated, and the space in the groove 15A of the housing 15 is decompressed with a decompression pump, and the convex part SA of the adhesive sheet S is adsorbed on the inner surface of the groove 15A. Since the inner surface of the groove 15A is formed of the porous member 15B, the convex portion SA can be uniformly adsorbed (step S19).
[0043]
Here, the pressing member 14 having the convex portion SA formed on the adhesive sheet S is lowered. Even if the pressing member 14 is lowered, since the convex portion SA of the adhesive sheet S is adsorbed to the inner surface of the groove 15A, the convex portion SA does not return (step S21).
[0044]
Next, the ultrasonic welding tool 16 is moved forward, the base portion that is the base portion of the convex portion SA of the adhesive sheet S is pressed at the tip portion, the base portions are brought into contact with each other, and pressed against the wall of the groove 15A of the housing 15 (step) S23). Next, the ultrasonic welding tool 16 oscillates ultrasonic waves to locally weld the base portion of the convex portion SA of the pressure-sensitive adhesive sheet S at the tip, and welds the entire circumference of the base portion of the annular convex portion SA by rotating the XYθ table 11 once (see FIG. Step S25).
[0045]
FIG. 4 shows this state. In the adhesive sheet S, the base SB of the convex portion SA is pressed by the tip of the ultrasonic welding tool 16 while the inner side of the pressing ring 17 is expanded and the interval between the chips T is expanded, and the bases SB are grooves. It is pressed against the wall of 15A and is welded locally by ultrasonic vibration.
[0046]
Here, the ultrasonic welding tool 16 is moved backward (step S27), the electromagnetic valve 21A is operated to release the pressure reduction in the groove 15A of the housing 15, and the housing 15 and the holding ring 17 are raised (step S29).
[0047]
Through the above steps, the space between the chips T of the wafer W adhered to the adhesive sheet S and diced into the individual chips T is widened. In this state, the adhesive sheet S is loosened near the outer periphery. The roots are in a state of being picked, and the wafers W held with the intervals between the individual chips T being enlarged can be transported frame by frame.
[0048]
This expansion is preferably performed immediately after dicing in a dicing apparatus. As described above, since the wafer W is transported in a frame while the state in which the distance between the chips T is enlarged is maintained, the edges of adjacent chips are brought into contact with each other due to vibration during transportation, and the edge portion is not chipped. And micro cracks are prevented from occurring.
[0049]
In the embodiment described above, the pressure-sensitive adhesive sheet S is pushed up from below and the convex portion SA is formed upward. However, the present invention is not limited to this, and the pressure-sensitive adhesive sheet S is pressed downward and convex downward. The part SA may be formed.
[0050]
Further, although the base portion SB of the convex portion SA of the pressure-sensitive adhesive sheet S is ultrasonically welded, it is not limited to ultrasonic welding, and may be locally welded by thermocompression bonding.
[0051]
【The invention's effect】
As described above, according to the expanding method and the expanding device of the present invention, the expanded state of the adhesive sheet is maintained while the diced plate is mounted on the frame. The plate-like object can be transported frame by frame while being maintained. Therefore, even if the distance between chips is extremely narrow, the edges of adjacent chips do not come into contact with each other due to vibration during conveyance, and the edge portion will not be chipped or microcracked. .
[0052]
In addition, since the expansion is performed with the plate-shaped object chucked on the chuck stage after dicing in the dicing machine, the distance between the chips can be increased immediately after dicing, and the plate-shaped object remains mounted on the frame. Since the expanded state is maintained, contact between the chips can be completely prevented even during conveyance in the dicing apparatus.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an expanding device according to an embodiment of the present invention. FIG. 2 is a flowchart showing an expanding method according to an embodiment of the present invention. Fig. 5 is a conceptual diagram showing a holding state. Fig. 5 is a perspective view showing a wafer mounted on a frame.
DESCRIPTION OF SYMBOLS 10 ... Expand apparatus, 11 ... XY (theta) table, 12 ... Chuck stage, 14 ... Pressing member, 15 ... Housing, 15A ... Groove (space part), 16 ... Ultrasonic welding tool (welding tool), 17 ... Holding ring, 20 ... Pressure reducing means, F ... frame, S ... adhesive sheet, SA ... convex portion, SB ... base, T ... chip, W ... wafer (plate-like material)

Claims (3)

An expanding method for expanding a space between the individual chips by expanding the adhesive sheet after dicing the plate-like object mounted on the ring-shaped frame via the adhesive sheet and diced into individual chips. In
After expansion, the expanded state of the pressure-sensitive adhesive sheet is maintained in a state where the plate-like object is mounted on the frame, and the plate-like object can be conveyed for each frame while maintaining an enlarged interval between the chips. ,
Expanding the pressure-sensitive adhesive sheet by forming a convex portion on the pressure-sensitive adhesive sheet between the frame and the plate-like object, and maintaining the expanded state of the pressure-sensitive adhesive sheet by welding or bonding the base of the convex portion. Expanding wherein the. 2. The expanding method according to claim 1 , wherein a base portion of the convex portion formed on the pressure-sensitive adhesive sheet is ultrasonically welded. 3. The expanding method according to claim 1, wherein the expansion of the pressure-sensitive adhesive sheet is performed after the dicing without removing the plate from the dicing chuck stage.

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