JP4397625B2 - Chip peeling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of peeling a chip attached to an adhesive tape without damaging it.
[0002]
[Prior art]
Individual semiconductor chips formed by dicing a semiconductor wafer are widely used in various electronic devices in a packaged and reinforced state, but the semiconductor chip itself requires a predetermined bending strength. .
[0003]
Therefore, as shown in FIG. 16, the bending strength is measured by supporting the semiconductor chip with two support rods 10 at a predetermined interval and applying a load W to the central portion with the load rod 11. . In this case, if the distance between the two support rods 10 (distance between fulcrums) is L, the load is W, the thickness of the semiconductor chip is h, and the width is b, the bending strength is (3LW / 2bh ² ) [Pa ].
[0004]
In order to measure the bending strength as described above, after the semiconductor wafer is diced in a state of being adhered to the adhesive tape, it is necessary to peel the formed semiconductor chip from the adhesive tape without damaging it. Therefore, an ultraviolet curable tape is used as the adhesive tape, and the semiconductor chip is peeled after the adhesive force is reduced by irradiating the adhesive tape with ultraviolet rays (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-12488
[Problems to be solved by the invention]
However, even when an ultraviolet curable tape is used as the adhesive tape, it is difficult to completely prevent damage when the semiconductor chip is peeled off from the adhesive tape. In particular, an extremely thin semiconductor chip having a thickness of 100 μm or less or 50 μm or less is highly likely to be damaged, and there is a problem that the bending strength cannot be measured.
[0007]
Further, when individual semiconductor chips formed by dicing the semiconductor wafer are peeled off from the dicing tape and die bonded, there is a possibility that the semiconductor chips may be damaged.
[0008]
Further, a cutting groove having a depth corresponding to the thickness of the semiconductor chip is formed in advance on the surface of the semiconductor wafer, and a protective tape (adhesive tape) is attached to the surface on which the cutting groove is formed, so that the back surface of the semiconductor wafer is formed. In the so-called tip dicing technique in which the semiconductor chip is divided into individual semiconductor chips by exposing the cut grooves from the back surface by grinding the semiconductor chip, there is a problem that the semiconductor chip is damaged when the semiconductor chip is peeled off from the protective tape.
[0009]
The above problems can occur not only in semiconductor chips but also in other chips. Therefore, when peeling a chip | tip from an adhesive tape, it has a subject in preventing damage to each chip | tip.
[0010]
[Means for Solving the Problems]
As a specific means for solving the above problems, the present invention is a chip peeling method in which individual chips formed by dividing a wafer having one surface attached to an adhesive tape are separated from the adhesive tape. Then, using a support plate having at least one suction hole formed and having an outer diameter larger than the outer diameter of the wafer, and a suction source for supplying suction force to the suction hole, liquid is dropped on the support plate to adhere the wafer. The other surface on which the tape is not attached is made to face the surface on which the liquid has been dropped, the placing step of placing the wafer on the support plate, and the suction force is applied to the suction holes of the support plate, a suction step of the wafer into close contact via the liquid, after the suction process, intervening adhesive tape between the peeling step of peeling from one surface of the wafer, the support plate and the wafer An evaporation step of evaporating the that the liquid to provide a method of removing at least composed chip and a pickup step for picking up the chip from the support plate.
[0011]
In this chip peeling method, the suction source is a chuck table that supports the entire surface of the support plate, a protective tape is attached to the surface of the support plate that supports the wafer, Additional requirements are that the support plate and the wafer are heated, that the liquid interposed between the support plate and the wafer is water or alcohol, and that the wafer is a semiconductor wafer.
[0012]
According to the chip peeling method configured as described above, the surface of the divided wafer, to which the adhesive tape is not attached, is placed on the support plate in which the suction holes are formed via the liquid and sucked into the suction holes. By applying force, the wafer can be brought into close contact with the support plate via the liquid, and the adhesive tape can be peeled off from the wafer in this state, so that individual chips are not damaged.
[0013]
Further, by evaporating the liquid interposed between the wafer and the support plate, the adhesion between the wafer and the support plate is lost, so that individual chips can be easily picked up after the adhesive tape is peeled off.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
As a first embodiment of the present invention, a case where a semiconductor wafer is peeled from an adhesive tape will be described as an example.
[0015]
The semiconductor wafer W1 shown in FIG. 1 is divided into individual semiconductor chips C1 by dicing. However, since the back surface of each semiconductor chip C1 is attached to the adhesive surface of the transparent adhesive tape T1, as a whole An almost circular wafer shape is maintained. A frame F is attached to the outer peripheral portion of the adhesive surface of the adhesive tape T1, and the semiconductor wafer W1 is integrated with the frame F via the adhesive tape T. In FIG. 1, the semiconductor wafer W1 is in a state in which the surface (surface) on which the circuit is formed and the adhesive tape T1 is not attached faces upward.
[0016]
In this way, the semiconductor wafer W1 integrated with the frame F through the adhesive tape T1 is turned upside down and placed on the support plate 1 as shown in FIG. At this time, the liquid 2 is dropped on the surface of the support plate 1 that faces the surface of the semiconductor wafer W1, so that the liquid 2 is interposed between the semiconductor wafer W1 and the support plate 1 ( Placement process). The liquid to be dropped is preferably a liquid that easily evaporates without affecting the quality of the semiconductor wafer W1, such as water or alcohol.
[0017]
In addition, the protective tape for protecting a circuit can also be affixed on the surface of the support plate 1 which supports the semiconductor wafer W1.
[0018]
The support plate 1 is formed of, for example, a hard member such as stainless steel, has an outer diameter larger than that of the semiconductor wafer W1, and has at least one suction hole 3 (9 in the illustrated example) extending from the front surface to the back surface. Has been. The inner diameter of the suction hole 3 is desirably about 0.1 mm to 0.5 mm.
[0019]
The support plate 1 on which the semiconductor wafer W1 is placed is sucked and held by the suction source 4. The suction source 4 in the illustrated example is a chuck table including a suction surface 5 formed in a planar shape by a porous member, for example, and a vacuum source 6 communicating with the suction surface 5, as shown in FIGS. 3 and 4. In addition, the support plate 1 is sucked and held on the suction surface 5 by the suction force transmitted from the vacuum source 6, and the suction force 3 is also applied to the suction holes 3 formed in the support plate 1 to support the entire surface of the semiconductor wafer W1. And sucking and holding (suction process). The support plate 1 may be assembled to the suction source 4 in advance. Further, the suction source 4 is not limited to the chuck table.
[0020]
By sucking the support plate 1 and the semiconductor wafer W1, the liquid 2 is interposed between the support plate 1 and the semiconductor wafer W1 with a small thickness as shown in FIG. The support plate 1 and the semiconductor wafer W1 can be firmly adhered to each other by the tension.
[0021]
After the support plate 1 and the semiconductor wafer W1 are brought into close contact with each other through the liquid 2 as shown in FIG. 5, when the adhesive tape T1 is peeled off from the back surface of the semiconductor wafer W1, the support plate 1 and the semiconductor wafer W1 become liquid. Since it is firmly adhered by 2, peeling can be easily performed (peeling process). Therefore, no strong force is applied to the semiconductor chip C1, and the semiconductor chip C1 is not damaged. Note that the direction of peeling is preferably an angle of 45 degrees with respect to the street.
[0022]
After the peeling process, as shown in FIG. 6, a pick-up process for picking up individual semiconductor chips C1 can be performed. If the evaporation process for evaporating the liquid 2 interposed between the semiconductor wafer W1 and the support plate 1 is performed before the pick-up process is performed, the adhesion between the semiconductor wafer W1 and the support plate 1 is lost. C1 can be easily picked up.
[0023]
The evaporation step can be performed, for example, by heating the support plate 1 or the semiconductor wafer W1 to about 80 ° C. When the support plate 1 is heated, it is easy and efficient if a means for heating is provided in the suction source 4.
[0024]
When measuring the bending strength after picking up, since the semiconductor chip C1 is not damaged, it is possible to obtain an appropriate test piece for the measurement. Further, the picked-up semiconductor chip C1 can be die-bonded, and can be easily transferred to another adhesive tape.
[0025]
Next, as a second embodiment of the present invention, a case will be described in which the present invention is applied to a technique in which a semiconductor wafer is divided into individual semiconductor chips by so-called first dicing. In the tip dicing method, as shown in FIG. 7, a cutting groove 7 having a depth corresponding to the thickness of the semiconductor chip is formed in advance on the surface of the semiconductor wafer W2, and as shown in FIGS. Then, a protective tape T2 which is an adhesive tape is attached to the surface where the cutting grooves 7 are formed, and the back surface of the semiconductor wafer W2 is ground in that state, and the cutting grooves 7 are formed from the back surface as shown in FIGS. Is divided into individual semiconductor chips C2.
[0026]
As shown in FIG. 12, the liquid 2 is dropped on the support plate 1, and the surface of the support plate 1 on which the liquid 2 is dropped faces the ground back surface of the divided semiconductor wafer W to face the suction source. As shown in FIG. 13, the liquid 2 is interposed between the support plate 1 and the semiconductor wafer W <b> 2 with a slight thickness, and the support plate 1 and the semiconductor wafer W <b> 2 are separated by the surface tension of the liquid 2. It can be firmly attached.
[0027]
In this state, when the protective tape T2 is peeled off as shown in FIG. 14, since the support plate 1 and the semiconductor wafer W2 are firmly adhered by the liquid 2, the protective tape T2 can be easily peeled off (peeling). Process). Therefore, no strong force is applied to the semiconductor chip C2, and the semiconductor chip C2 is not damaged.
[0028]
Then, after the protective tape T2 is peeled off, the individual semiconductor chips C2 can be picked up as shown in FIG. If the support plate 1 or the divided semiconductor wafer W2 is heated before the pickup, the liquid 2 evaporates and the adhesion force is lost, so that the pickup can be performed easily and smoothly and the semiconductor chip C2 is damaged. There is nothing.
[0029]
When the picked-up semiconductor chip C1 is used for the measurement of the bending strength, since there is no damage, it can be set as an appropriate test piece for the measurement. Further, the picked-up semiconductor chip C2 can be die-bonded, and can be easily transferred to another adhesive tape.
[0030]
In this embodiment, the case where the semiconductor chip is peeled from the adhesive tape has been described as an example, but the chip is not limited to the semiconductor chip. Alternatively, the support plate and the vacuum source may be integrated to form a chuck table, and a heat source such as a heater may be disposed below the support plate. Furthermore, when a buffer material such as a protective tape for protecting the chip is attached to the upper surface of the support plate 1 to form the suction hole, the chip does not directly contact the support plate made of metal or the like, When there are bumps and other irregularities, the protective tape absorbs the irregularities and the adhesion is improved.
[0031]
【The invention's effect】
As described above, according to the chip peeling method according to the present invention, the surface of the wafer after division on which the adhesive tape is not attached is placed on the support plate in which the suction holes are formed via the liquid, By applying a suction force to the suction holes, the wafer can be brought into close contact with the support plate via the liquid, and the adhesive tape can be peeled off from the wafer in that state, so it is safe and easy without damaging individual chips. Can be peeled off.
[0032]
Further, by evaporating the liquid interposed between the wafer and the support plate, the adhesion between the wafer and the support plate is lost, so that individual chips can be easily picked up after the adhesive tape is peeled off. The picked-up chip can be used as an appropriate test piece for measuring the bending strength, or the chip can be die-bonded as it is or transferred to another adhesive tape or the like.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a semiconductor wafer integrated with a frame via an adhesive tape.
FIG. 2 is a perspective view showing a mounting process.
FIG. 3 is a perspective view showing a suction process.
FIG. 4 is a cross-sectional view showing a state in which a semiconductor wafer is sucked.
FIG. 5 is a perspective view showing a peeling process.
FIG. 6 is a perspective view showing a pickup process.
FIG. 7 is a perspective view showing a semiconductor wafer in which cutting grooves are formed.
FIG. 8 is a perspective view showing a state where a protective tape is attached to the semiconductor wafer.
FIG. 9 is a cross-sectional view showing a state where a protective tape is attached to the semiconductor wafer.
FIG. 10 is a perspective view showing a semiconductor wafer divided into semiconductor chips by prior dicing.
FIG. 11 is a cross-sectional view showing a semiconductor wafer divided into semiconductor chips by prior dicing.
FIG. 12 is a perspective view showing a mounting process.
FIG. 13 is a cross-sectional view showing a state in which a semiconductor wafer is sucked.
FIG. 14 is a front view showing a peeling step.
FIG. 15 is a perspective view showing a pickup process.
FIG. 16 is a perspective view showing a bending strength test.
[Explanation of symbols]
W1, W2 ... Semiconductor wafer T1 ... Adhesive tape T2 ... Protective tape C1, C2 ... Semiconductor chip F ... Frame 1 ... Support plate 2 ... Liquid 3 ... Suction hole 4 ... Suction source 5 ... Suction surface 6 ... Vacuum source

Claims (6)

A chip peeling method in which individual chips formed by dividing a wafer having one surface attached to an adhesive tape are separated from the adhesive tape,
Using a support plate in which at least one suction hole is formed and having an outer diameter larger than the outer diameter of the wafer, and a suction source for supplying a suction force to the suction hole;
Placing the liquid on the support plate, placing the other surface of the wafer to which the adhesive tape is not attached facing the surface on which the liquid is dropped, and placing the wafer on the support plate;
A suction step in which a suction force is applied to the suction holes of the support plate to bring the support plate and the wafer into close contact via the liquid;
After the suction step, a peeling step of peeling the adhesive tape from one side of the wafer ;
An evaporation step of evaporating a liquid interposed between the support plate and the wafer;
A chip peeling method comprising at least a pickup step of picking up a chip from the support plate . 2. The chip peeling method according to claim 1 , wherein the suction source is a chuck table that supports the entire surface of the support plate. Chip separation method according to claim 1 or 2 protective tape is stuck on the surface on the side that supports the wafer support plate. In the evaporation process, the chip separation method according to claim 1, 2 or 3 and the support plate and the wafer is heated. Liquid interposed between the support plate and the wafer, the chip separation method according to any one of claims 1 to 4 which is water or alcohol. Wafer chip separation method according to any one of claims 1 to 5 which is a semiconductor wafer.

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