JP2021163802A - Chip transfer method and chip transfer device - Google Patents

Abstract

To provide a chip transfer method and a chip transfer device for transferring a chip from a dicing tape to a substrate which is capable of realizing laser lift off so as to make it possible to use a laser lift off method even for a semiconductor chip comprising silicon.SOLUTION: There are provided a chip transfer method and a chip transfer device. The chip transfer method transfers a large number of semiconductor chips formed by dicing a wafer held on a dicing tape to a transfer destination substrate having an adhesive layer, and includes an ultraviolet ray radiation step of radiating ultraviolet ray to an ultraviolet ray curing type adhesive for fixing the semiconductor chips to the dicing tape through the dicing tape for decreasing the adhesive force of the adhesive, a bonding step of arranging the transfer destination substrate and the dicing tape so that the adhesive face of the transfer destination substrate and the semiconductor chips face and closely contact with each other, and a removing step of removing the dicing tape from the semiconductor chips in a state where the semiconductor chips are closely contact to the transfer destination substrate.SELECTED DRAWING: Figure 3

Description

The present invention relates to a chip transfer method and a chip transfer device for transferring a large number of semiconductor chips separated on a dicing tape to a transfer destination substrate.

In semiconductor device manufacturing, a semiconductor wafer whose back surface is polished to the minimum thickness after a wafer processing process is fixed on a dicing tape and then divided by a blade or the like and separated into a large number of semiconductor chips (dicing). Then, each semiconductor chip is mounted on a substrate such as an interposer to form a semiconductor device. That is, after the semiconductor wafer W is fixed to the adhesive surface side of the dicing tape 10 whose outer periphery is fixed to the ring frame 3 as shown in FIG. 10, the semiconductor wafer W is fixed to a large number of semiconductor chips C as shown in FIG. It is separated and each semiconductor chip C goes through a mounting process to become a semiconductor device.

Conventionally, the chips C individually separated on the dicing tape 10 as shown in FIG. 12 have been picked up one by one and used in the mounting process (Patent Document 1 and the like). That is, in the state of being separated as shown in FIG. 13 (a), the collet 92 sucks and holds the semiconductor chip C to be picked up with the needle 91 pushed up through the dicing tape 10 as shown in FIG. 12 (b). Then, it was generally supplied to the mounting device side.

JP-A-2017-130499 Japanese Unexamined Patent Publication No. 2012-22208

With the recent development of so-called IOT, it has become natural that a large number of semiconductor devices are mounted on various devices, and there is a demand for high speed in semiconductor processes to support mass production. Therefore, it is extremely inefficient to pick up the semiconductor chips C one by one as shown in FIG.

On the other hand, in the application of LED displays, practical study of a method of transferring μLEDs and mini LEDs to other substrates at high speed by a laser lift-off method is in progress.

Therefore, if the laser lift-off method can be used for the semiconductor chip C as well, the process efficiency can be improved, but there are many problems at present. This is because the LED is a GaN-based semiconductor formed on the sapphire substrate, so the LED chip is peeled off by the gas generated by the decomposition of GaN by irradiating the laser beam of a predetermined wavelength from the sapphire side, but dicing. This is due to the fact that the semiconductor chip on the tape is made of silicon and therefore cannot exhibit the same phenomenon. Further, since the adhesive layer of the dicing tape is generally UV-curable, the adhesive force for holding the semiconductor chip C by irradiating the dicing tape 10 with the ultraviolet laser beam L as shown in FIG. 14 (b). Can be reduced, but it is difficult to even peel it off.

Further, since some adhesives generate gas when irradiated with ultraviolet rays, it is conceivable to use them for the adhesive layer of the dicing tape 10, but in such adhesives, the semiconductor wafer W is bladed. It is not possible to secure the adhesive strength required when dividing by such means.

The present invention has been made in view of the above problems, and is a chip transfer method for transferring from a dicing tape to a substrate capable of performing the lift-off in order to enable the laser lift-off method to be used even for a semiconductor chip made of silicon. It provides a chip transfer device.

In order to solve the above problems, the invention according to claim 1 is
This is a chip transfer method in which a large number of semiconductor chips obtained by fragmenting a wafer held on a dicing tape are transferred to a transfer destination substrate having an adhesive layer.
An ultraviolet irradiation step of irradiating an ultraviolet curable pressure-sensitive adhesive that fixes the semiconductor chip to the dicing tape with ultraviolet rays through the dicing tape to reduce the adhesive strength of the pressure-sensitive adhesive, and an adhesive surface of the transfer destination substrate. The bonding step of arranging the transfer destination substrate and the dicing tape so that the semiconductor chip and the semiconductor chip are in close contact with each other, and the dicing tape from the semiconductor chip in a state where the semiconductor chip is in close contact with the transfer destination substrate. This is a chip transfer method including a peeling step of peeling.

The invention according to claim 2 is the chip transfer method according to claim 1.
In the peeling step, a pressing jig having a pressure region is used, and the semiconductor chip from which the dicing tape is peeled is pressed by the pressing jig through the dicing tape, and the pressure region is pressed by the dicing. This is a chip transfer method characterized by peeling off the dicing tape on the side opposite to the direction of movement while moving the dicing tape on the tape surface.

The invention according to claim 3 is the chip transfer method according to claim 2.
This is a chip transfer method in which the direction in which the dicing tape is peeled off has an angle of 45 ± 15 degrees with respect to any side of the semiconductor chip.

The invention according to claim 4
A chip transfer device that transfers a large number of semiconductor chips, which are individualized wafers held on a dicing tape, to a transfer destination substrate having an adhesive layer.
A ring frame for fixing the periphery of the dicing tape, an ultraviolet curable adhesive for fixing the semiconductor chip to the dicing tape, and an ultraviolet irradiation means for irradiating the dicing tape with ultraviolet rays for reducing the adhesive force. The transfer destination substrate stage that attracts and holds the transfer destination substrate from the opposite side of the adhesive surface and the ring frame are driven so as to be arranged so that the adhesive surface of the transfer destination substrate and the semiconductor chip face each other and are in close contact with each other. A chip transfer device including a bonding means and a peeling mechanism for peeling the dicing tape from the semiconductor chip while the semiconductor chip is in close contact with the transfer destination substrate.

The invention according to claim 5 is the chip transfer device according to claim 4.
A pressing jig having a pressurizing region longer than the diameter of the wafer, a pressurizing region moving means for relatively moving the pressing region in the in-plane direction of the dicing tape, and the pressurizing region. This is a chip transfer device having a tension means for applying tension to the dicing tape to separate it from the semiconductor chip, which is opposite to the moving direction of the pressure region moving means.

The invention according to claim 6 is the chip transfer method according to claim 5.
A chip transfer device in which the direction of the pressure region has an angle of 45 ± 15 degrees with respect to any side of the semiconductor chip.

By using the chip transfer method and the chip transfer device of the present invention, even a semiconductor chip made of silicon on a dicing tape can be transferred to a substrate on which the laser lift-off method can be used.

The ultraviolet irradiation step and the bonding step in the embodiment of the present invention will be described. It is a diagram showing (a) a chip component separated on a dicing tape, and (b) using the chip component as a transfer destination substrate. It is a figure which shows the state which faced each other, (c) is the figure which shows the state which changed from the same facing state to the close contact state, and is irradiating ultraviolet rays through a dicing tape. The peeling step in the embodiment of the present invention is described, and is a diagram showing (a) a state in which the dicing tape is peeled from the semiconductor chip, and (b) a diagram showing a state in which the semiconductor chip is transferred to the transfer destination substrate. A specific example of the peeling step in the embodiment of the present invention will be described. It is a diagram showing a state in which the semiconductor chip on the dicing tape and the transfer destination substrate are in close contact with each other, and (b) the peeling of the dicing tape is started. It is a figure which shows the state which was in the state, (c) is a figure which shows the process of peeling off a dicing tape. Another specific example of the peeling step in the embodiment of the present invention will be described. It is a diagram showing a state in which the semiconductor chip on the dicing tape and the transfer destination substrate are in close contact with each other, and (b) the peeling of the dicing tape is performed. It is a figure which shows the started state, (c) is a figure which shows the process of peeling off a dicing tape. It is a figure explaining about the diameter of the semiconductor wafer and the pressure region of the holding jig which concerns on embodiment of this invention. It is a figure explaining the relationship between the direction of the semiconductor chip arrangement and the angle of the pressure region which concerns on embodiment of this invention. It is an enlarged view explaining the relationship between the direction of the semiconductor chip arrangement and the angle of the pressure region which concerns on embodiment of this invention. It is a block diagram which describes the component of the chip transfer apparatus which concerns on embodiment of this invention. The laser lift-off using the transfer destination substrate according to the embodiment of the present invention will be described. It is a diagram showing (a) a state in which a semiconductor chip is transferred to the transfer destination substrate, and (b) is formed on an adhesive layer through the transfer destination substrate. It is a figure which shows the state which irradiates a laser beam, (c) is the figure which shows the state which the semiconductor chip was peeled off by ablation by the laser beam irradiation. A usage pattern of the dicing tape will be described, and is (a) a top view of a state in which the outer peripheral portion is fixed to a ring frame, and (b) a cross-sectional view of the same state. A usage pattern of the dicing tape will be described, and (a) is a top view of a state in which a semiconductor wafer is attached, and (b) is a cross-sectional view of the same state. A usage pattern of the dicing tape will be described, and (a) is a top view showing a state in which a semiconductor wafer is divided into a large number of semiconductor chips, and (b) is a cross-sectional view in the same state. A conventional method of picking up a semiconductor chip is described. It is (a) a cross-sectional view showing a large number of semiconductor chips fragmented on a dicing tape, and (b) picks up one of the fragmented semiconductor chips. It is a figure explaining the process of doing. It is a figure explaining the problem when the laser lift-off method is used for the semiconductor chip on a dicing tape, (a) is the cross-sectional view which shows a large number of semiconductor chips individualized on a dicing tape, and (b) is It is a figure which shows the state which tries to separate one of the separated semiconductor chips by a laser beam.

Embodiments of the present invention will be described with reference to the drawings. 1 and 2 are diagrams illustrating a chip transfer method according to an embodiment of the present invention.

First, FIG. 1 illustrates the ultraviolet irradiation step and the bonding step of the present invention. FIG. 1A shows a state in which the wafer W on the dicing tape whose outer peripheral portion is fixed to the ring frame 3 is divided and separated into a large number of semiconductor chips C, as in FIG. 12B. .. In the state of FIG. 1A, the semiconductor chip C is firmly held and fixed to the dicing tape 10 by an adhesive. FIG. 1B shows a preparatory step for performing the bonding step, and shows a state in which the semiconductor chip C on the dicing tape and the adhesive surface of the transfer destination substrate 2 face each other. The relative distance is shortened in the vertical direction (Z direction), and all the semiconductor chips C are brought into close contact with the transfer destination substrate 2, and the bonding process is completed. FIG. 1C is an ultraviolet irradiation step of irradiating the dicing tape 10 with ultraviolet rays for curing the pressure-sensitive adhesive at the interface with the semiconductor chip C. This ultraviolet irradiation step reduces the adhesive strength for holding the semiconductor chip C.

By the way, even if the adhesive strength is reduced by the ultraviolet irradiation step, the semiconductor chip C is hardly peeled off from the dicing tape 10. Therefore, the ultraviolet irradiation may be performed through the dicing tape 10 in the state of FIG. 1A. .. That is, the bonding step may be performed after the ultraviolet irradiation step.

FIG. 2 describes the peeling process. FIG. 2A shows an outline of the peeling process, in which the non-adhesive surface of the transfer destination substrate 2 is adsorbed and held by the transfer destination substrate stage 4, and the adhesive surface of the transfer destination substrate 2 and the semiconductor chip C are in close contact with each other. It shows how the dicing tape 10 is peeled off from the surface. By peeling the dicing tape 10 from the semiconductor chip C as shown in FIG. 2A, the semiconductor chip C is transferred to the transfer destination substrate 2 as shown in FIG. 2B.

Since the state of FIG. 2A is after the ultraviolet irradiation step, the adhesive force between the semiconductor chip C and the dicing tape 10 is weakened, but some of them are not transferred to the transfer destination substrate 2. That is, simply pulling the dicing tape 10 as shown in FIG. 2A causes the semiconductor chip C to be peeled off from the transfer destination substrate 2 while remaining attached to the dicing tape 10 due to the adhesive strength between the semiconductor chip C and the transfer destination substrate 2. There is also a semiconductor chip C that does.

Therefore, FIGS. 3 to 7 show specific examples of the peeling mechanism and the peeling step considered for surely transferring the semiconductor chip C to the transfer destination substrate in the peeling step.

First, FIG. 3 shows an example of the peeling mechanism in the embodiment. FIG. 3A shows a state before the start of peeling. Here, the dicing tape 10 is a base 100 on which an adhesive layer 101 made of an adhesive is laminated.

The base 100 is made of a flexible resin film, specifically, vinyl chloride, polyolefin resin, polyester resin and the like are used, and the adhesive layer 101 has strong holding power and ultraviolet curability. As a possessor, a blend of an acrylic acid ester copolymer and an ultraviolet curable resin or the like is used.

The transfer destination substrate 2 is a base 20 on which an adhesive layer 21 made of an adhesive is laminated. Unlike the adhesive layer 101 of the dicing tape 10, the adhesive layer 21 in the transfer destination substrate 2 preferably decomposes components to generate gas (ablation) when it receives laser light of a specific wavelength. Further, the base 20 is preferably one that transmits a wavelength that causes ablation and has excellent flatness, and a thin plate such as glass, ceramics, or silicon can be used. Further, the non-adhesive surface (the surface opposite to the adhesive layer 21) of the transfer destination substrate 2 is in close contact with the transfer destination substrate holding stage 4, and the transfer destination substrate 2 is fixed.

After that, as shown in FIG. 3B, the dicing tape 10 is peeled off from the outer peripheral portion. At that time, the dicing tape is attached to the semiconductor chip C which is about to peel off the dicing tape 10 with the holding jig 5. The dicing tape 10 on the side opposite to the moving direction is peeled off by using the tensioning means 6 while moving the pressing jig 5 while pressurizing through the pressing jig 5, and the movement of the pressing jig 5 causes FIG. 3 (c). The dicing tape 10 is sequentially peeled off as described above. From FIG. 3, since the holding jig 5 is moving (on the dicing tape surface) while pressing the semiconductor chip C against the transfer destination substrate through the dicing tape 10, the dicing tape 10 on the side opposite to the moving direction is pulled up. As a result, it can be seen that the dicing tape 10 with the semiconductor chip C attached is not peeled off. That is, the semiconductor chip C can be reliably transferred from the dicing tape 10 to the transfer destination substrate 2.

FIG. 5 shows a top view of the holding jig 5 on the surface of the dicing tape 10. Since the semiconductor chip C exists on the dicing tape 10 over the diameter of the semiconductor wafer W, the holding jig 5 is used. The width 5 W needs to be longer than the diameter of the semiconductor wafer W.

The tensioning means 6 applies tension to the dicing tape 10, and in FIG. 3, the roll 6A and the roll 6B rotate in a relationship of a feed roll and a nip roll to apply tension. Only one of the rolls may function as a suction roll and apply tension, or may function as a take-up roll and apply tension.

FIG. 3 shows an example in which the holding jig 5 and the tension means 6 move to peel off the dicing tape 10 while the transfer destination substrate 2 is fixed to the transfer destination substrate stage 4. The dicing tape 10 may be peeled off while the 2 is slid and moved. An example thereof is shown in FIG. Although the positions of the pressing jig 5 and the tensioning means 6 are fixed in FIG. 4, the pressing jig 5 and the tensioning means 6 are moved by sliding the transfer destination substrate 2 in the in-plane direction by the transfer destination substrate moving means 7. Since the dicing tape 2 moves relative to the transfer destination substrate 2 (similar to the example of FIG. 3), the dicing tape 2 can be peeled off as shown in FIGS. 4 (b) and 4 (c). In the peeling mechanism having the configuration shown in FIG. 4, the pressure roll 8 may be arranged as shown in the figure in order to suppress the lifting of the transfer destination substrate 2.

By the way, in the peeling step, when the pressing jig 5 peels off the dicing tape 10 while pressing the semiconductor chip C through the dicing tape 10 (which is about to peel off the dicing tape 10) against the transfer destination substrate, the pressing jig 5 is pressed and cured. The pressure region of the tool 5 is preferably linear as shown in FIG. In addition to this, it was also found that the peelability is better when the semiconductor chips C having a rectangular surface shape are inclined with respect to the arrangement (division direction). Specifically, it is best to incline the pressurizing region of the pressing jig 5 by 45 degrees with respect to any side of the semiconductor chip in the XY plane shown in FIG. 6 (and FIG. 7 which is a partially enlarged view thereof). It is preferable, but it is desirable that it is in the range of 45 ± 15 degrees.

FIG. 8 shows the configuration of the chip transfer device 1 that performs the ultraviolet irradiation step, the bonding step, and the peeling step as described above in a block diagram. In FIG. 8, the chip transfer device 1 is roughly divided into an ultraviolet irradiation means, a bonding means, and a peeling means, and is controlled by a control unit 9.

The ultraviolet irradiation means includes a ring frame driving means 30 for driving the ring frame 3, an ultraviolet light source 31 and a control unit 32, and has a function of irradiating an appropriate position through the dicing tape 10 with ultraviolet rays. Here, the control unit 32 may not be provided, and the control unit 9 may have the same function.

The bonding means is controlled by the control unit 9 to carry out the bonding process with the ring frame driving means 30 and the transfer destination substrate stage 4 as basic components.

The peeling means is controlled by the control unit 9 together with the transfer destination substrate stage 4 or the transfer destination substrate moving means 7 with the pressing jig 5 and the tension means 6 as basic components.

Up to this point, the process of transferring the semiconductor chip C to the transfer destination substrate 2 and the like have been described, but the semiconductor chip C held by the adhesive layer 21 of the transfer destination substrate 2 as shown in FIG. 9A is shown in FIG. 2 (b). ), The laser beam L having a predetermined wavelength is irradiated through the transfer destination substrate 2, and the adhesive layer 21 can be easily peeled off as shown in FIG. 9C by ablation with gas or the like at the time of decomposition. That is, the semiconductor chip C transferred to the transfer destination substrate 2 of the present invention can be easily transferred (mounted) to another substrate by laser lift-off.

1 Chip transfer device 2 Transfer destination board 3 Ring frame 4 Transfer destination board stage 5 Holding jig 6 Tension means 7 Transfer destination board moving means 8 Pressurizing roll 9 Control unit 10 Dicing tape 20 base 21 Adhesive layer 100 base 101 Adhesive layer C Semiconductor chip W semiconductor wafer

Claims (6)

This is a chip transfer method in which a large number of semiconductor chips obtained by fragmenting a wafer held on a dicing tape are transferred to a transfer destination substrate having an adhesive layer.
An ultraviolet irradiation step of irradiating an ultraviolet curable pressure-sensitive adhesive that fixes the semiconductor chip to the dicing tape with ultraviolet rays through the dicing tape to reduce the adhesive strength of the pressure-sensitive adhesive.
A bonding step of arranging the transfer destination substrate and the dicing tape so that the adhesive surface of the transfer destination substrate and the semiconductor chip face each other and adhere to each other.
A chip transfer method comprising a peeling step of peeling the dicing tape from the semiconductor chip while the semiconductor chip is in close contact with the transfer destination substrate. The chip transfer method according to claim 1.
In the peeling step, a holding jig having a pressurized region is used.
With the holding jig, the semiconductor chip from which the dicing tape is peeled off is pressed through the dicing tape.
While moving the pressure region on the dicing tape surface,
A chip transfer method comprising peeling off the dicing tape on the side opposite to the moving direction. The chip transfer method according to claim 2.
A chip transfer method in which the direction in which the dicing tape is peeled off has an angle of 45 ± 15 degrees with respect to any side of the semiconductor chip. A chip transfer device that transfers a large number of semiconductor chips, which are individualized wafers held on a dicing tape, to a transfer destination substrate having an adhesive layer.
A ring frame that fixes the circumference of the dicing tape and
An ultraviolet irradiation means for irradiating an ultraviolet curable pressure-sensitive adhesive that fixes the semiconductor chip to the dicing tape with ultraviolet rays that reduce the adhesive strength through the dicing tape.
A transfer destination substrate stage that attracts and holds the transfer destination substrate from the opposite side of the adhesive surface,
A bonding means that drives the ring frame and arranges the adhesive surface of the transfer destination substrate and the semiconductor chip so as to face each other and adhere to each other.
A chip transfer device provided with a peeling mechanism for peeling the dicing tape from the semiconductor chip while the semiconductor chip is in close contact with the transfer destination substrate. The chip transfer device according to claim 4, wherein the peeling mechanism is
A holding jig having a pressure region longer than the diameter of the wafer,
A pressurizing region moving means for relatively moving the pressurizing jig in the in-plane direction of the dicing tape, and a pressurizing region moving means.
A chip transfer device having a tension means for applying a tension to the dicing tape on the dicing tape on the side opposite to the moving direction of the pressure region moving means with respect to the pressure region. The chip transfer method according to claim 5.
A chip transfer device in which the direction of the pressure region has an angle of 45 ± 15 degrees with respect to any side of the semiconductor chip.

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