TWI873961B - Temporary substrate - Google Patents

Abstract

The temporary substrate of the present invention is used to temporarily fix multiple chips. The temporary substrate includes a supporting body and a microstructure layer. The supporting body has a supporting surface. The microstructure layer is connected to the supporting body and is located on the supporting surface, and includes multiple microstructures. Adjacent microstructures in the multiple microstructures are arranged at intervals and are used to temporarily fix multiple chips. Each of the multiple chips is attached to at least one of the multiple microstructures.

Description

Temporary substrate

The present invention relates to a carrier of a semiconductor device, and in particular to a temporary storage substrate.

Currently, the chip on wafer (COW) of light-emitting components (such as Micro LED) that have been completed through the chip process needs to go through a transfer process to transfer the light-emitting components on the wafer to a temporary substrate (COC) for subsequent mass transfer processes.

The current temporary substrate structure includes a supporting substrate and an adhesive layer formed on the supporting substrate. The adhesive layer is a complete plane to adhere to the light-emitting element to achieve the purpose of temporary fixation. The adhesive layer of this temporary substrate will adhere to the entire pad of the light-emitting element, that is, a continuous temporary bonding surface, so that the transfer head needs to use a larger pick-up force to pick up the light-emitting element on the temporary substrate during the mass transfer process. Therefore, it is not easy for the current pick-up head to accurately pick up a sufficient number of light-emitting elements, which affects the pick-up yield. The affected problems include missing crystals, flipping crystals, and misalignment caused by not picking up accurately during picking. Wafer missing means that the pick-up force of the transfer head is less than the adhesive force of the temporary substrate, resulting in the transfer head not picking up enough light-emitting components. Wafer flipping means that the light-emitting components are flipped during the pick-up process, resulting in the solder pads of the light-emitting components not facing downwards. Misalignment means that the light-emitting components are displaced during the pick-up process. Therefore, all of the above phenomena will affect the subsequent mass transfer yield after picking up.

In view of the above shortcomings, the temporary substrate of the present invention destroys the continuous bonding surface through microstructures to allow mass transfer to correctly pick up the chip, thereby improving the yield of mass transfer.

In order to solve the above problems, the temporary substrate of the present invention is used to temporarily fix multiple chips. The temporary substrate includes a supporting body and a microstructure layer. The supporting body has a supporting surface. The microstructure layer is connected to the supporting body and is located on the supporting surface, and includes multiple microstructures. Adjacent microstructures in the multiple microstructures are arranged at intervals and are used to temporarily fix multiple chips. Each of the multiple chips is attached to at least one of the multiple microstructures.

In this way, the chip is bonded together with multiple microstructures to reduce the contact area between the microstructure and the chip. This not only can firmly fix the chip, but also facilitates the subsequent mass transfer picking operation to improve the mass transfer yield.

The detailed structure or features of the temporary storage substrate provided by the present invention will be described in the detailed description of the implementation method in the following. However, those skilled in the art should understand that the detailed description and the specific embodiments listed for implementing the present invention are only applicable to the description of the present invention and are not intended to limit the scope of the patent application of the present invention.

10: Temporarily store the substrate

11: Support the main body

111: Support surface

13: Microstructure layer

131: Microstructure

133: Debondable material layer

15: Adhesive layer

17: Carrier board

30: Chip

31: Chip body

33:Welding pad

50: Pickup head

70: Degumming equipment

71: Ultraviolet light

FIG1 is a schematic diagram of a first embodiment of a wafer temporarily fixed on a temporary storage substrate of the present invention.

Figure 2 is a partial cross-sectional view of Figure 1.

FIG3 is a partial top view of the temporary substrate with the chip omitted in FIG1.

FIG4 is a schematic diagram of the pickup head attaching a wafer, continuing from FIG2.

Figure 5 is a continuation of Figure 4, showing the schematic diagram of the pickup head picking up the chip.

FIG6 is a schematic diagram of a second embodiment of the temporary substrate of the present invention.

FIG7 is a schematic diagram continuing from FIG6, showing the pickup head attached to the chip and the laser light irradiating the pickup range.

FIG8 is a schematic diagram of a third embodiment of the temporary substrate of the present invention.

The applicant first explains that throughout the entire specification, including the embodiments described below and the claims of the patent application, the terms related to direction are based on the directions in the drawings. Secondly, in the embodiments and drawings to be described below, the same component numbers represent the same or similar components or their structural features.

As shown in Figures 1 to 3, Figure 1 is a schematic diagram of multiple chips 30 being temporarily fixed on the temporary substrate 10 of the present invention, Figure 2 is a partial cross-sectional view of Figure 1, and Figure 3 is a top view of the temporary substrate 10 in Figure 1 without the chip 30. Among them, since the microstructure size of the microstructure layer is relatively small and it is not easy to clearly show it in Figure 1, it is represented by Figures 2 and 3.

The temporary substrate 10 of the present invention is used to temporarily fix multiple chips 30. Each of the multiple chips 30 includes a chip body 31 and two pads 33 connected to the chip body 31. The temporary substrate 10 includes a supporting body 11 and a microstructure layer 13. The supporting body 11 has a supporting surface 111. The microstructure layer 13 is connected to the supporting body 11 and is located on the supporting surface 111, and includes multiple microstructures 131. The supporting body 11 and the microstructure layer 13 are made of the same material, such as a polymer elastic material (Polydimethylsiloxane, PDMS). Adjacent microstructures in the multiple microstructures 131 are arranged at intervals and are used to temporarily fix the multiple chips 30. The spacing can be planned based on the fixed position of the visible chip 30 or the pad 33. A single pad 33 of each chip 30 is bonded to two microstructures 131, so that the continuity of the bonding is destroyed by the spaced microstructures 131. In other embodiments, a single pad 33 of each chip 30 can also be bonded to only one microstructure or more microstructures, such as three, four or more.

In this embodiment, the chip 30 is a light-emitting element. The bonding surface size of each microstructure 131 is smaller than the bonding surface size of a single pad 33 of each chip 30. In the figure, the bonding surface of each microstructure 131 is the plane of the top of each microstructure 131, and the bonding surface of the pad 33 is the bottom surface of the pad 33. The bonding surface has an attachment force, such as electrostatic force, magnetic force, or adhesive force, which is used to connect the bonding surface to achieve the purpose of temporarily fixing the chip 30.

In addition, the microstructure 131 includes a protrusion protruding from the supporting body 11, and the bonding surface is located at the top of the protrusion. The shape of the protrusion can be a three-dimensional structure such as a hemisphere, a conical column, a cylinder, a square column, a triangular column, a plateau, etc., wherein the bottom area of the conical column is larger than the bonding surface, and conversely, the bottom area of the plateau is smaller than the bonding surface. FIG. 3 is represented by a cylinder. In other embodiments, in addition to contacting the pad 33, the microstructure 131 may also contact the chip body 31 of the chip 30. Therefore, the microstructure 131 is not limited to contacting the pad 33.

As shown in Figures 4 and 5, when performing a mass transfer process, the pick-up head 50 of the equipment will first be bonded to the selected chip 30, and then the pick-up head 50 will be lifted up to pick up the bonded chip 30 and transfer it to the next process, such as bonding and soldering on the circuit substrate. Since the microstructure layer 13 is composed of multiple microstructures 131, and the bonding surfaces of the microstructures 131 are discontinuous, the pick-up head can pick up the chip more easily than the traditional continuous bonding surface, thereby improving the transfer yield.

However, the bonding surfaces of the microstructure 131 are discontinuous, which may result in insufficient bonding force for temporarily fixing multiple chips 30, causing the chips 30 to fall. To solve this problem, in another embodiment of the present invention, as shown in FIG6 , the microstructure 131 further includes a removable adhesive material layer 133 (bold black line in the figure), and the removable adhesive material layer 133 is formed on the surface of the protrusion. In general, the adhesive force of the removable adhesive material layer 133 is greater than the bonding surface of the protrusion, but after a degumming operation, the adhesive force of the removable adhesive material layer 133 is destroyed, so that the chip 30 is easier to pick up. The debonding material layer 133 can be formed on the surface of the convex portion 131 by spraying, which can quickly and reliably form the debonding material layer on the surface of the convex portion 131. In other embodiments, the debonding material layer 133 can also be formed on the surface of the convex portion 131 by coating, bonding, etc. The coating operation is to coat the surface of the convex portion 131 with the debonding material, and the bonding operation is to bond the surface of the convex portion 131 with the debonding material.

As shown in FIG. 7 , compared with FIG. 4 and FIG. 5 , the mass transfer process in FIG. 7 needs to increase the debonding operation (process). In this embodiment, the debondable material layer includes UV debonding. Therefore, the debonding operation is to irradiate the pickup range of the pickup head 50 with ultraviolet (UV) light 71 generated by the debonding device 70, so that the adhesion of the debondable material layer 133 in the pickup range disappears or decreases, so that the pickup head can surely pick up the chip 30. In the figure, the ultraviolet light 71 is only represented by two arrows. In fact, the range between the two arrows is the part with ultraviolet light. In other embodiments, the debonding operation can also be performed by water or heat energy. For example, when the debondable material includes a thermal debonding material, the debonding effect can be achieved by a hot plate, an oven, far infrared light or laser light. When the debondable material includes a hydrolyzable material, the debonding effect can be achieved by dissolving the debonding material in water.

After the adhesive force of the removable material layer 133 is destroyed, its adhesive force cannot be restored, but the adhesive force of the microstructure 131 can be restored. Therefore, if the adhesive force of the removable material layer 133 is to be restored, it can be restored by re-spraying, coating, or sticking the removable material.

As shown in FIG8 , in another embodiment of the present invention, the temporary substrate 10 further includes an adhesive layer 15 and a carrier 17. The adhesive layer 15 connects the supporting body 11 and the carrier 17. The material of the adhesive layer 15 is a light-transmitting polymer material, but is different from the material of the supporting body 11. The rigidity of the carrier 17 (such as glass, sapphire substrate, etc.) is greater than that of the supporting body 11, that is, the carrier 17 is less likely to deform than the supporting body 11, and can provide a better support effect for the chip 30. In this way, in the mass transfer operation, the pick-up head presses down to pick up the chip to improve the pick-up yield, so as to avoid some chips sinking too much and not being picked up. In this embodiment, a debondable material layer 133 may be formed on the microstructure 131, but in other embodiments, the microstructure 131 may not have a debondable material layer 133.

Finally, the components disclosed in the above-mentioned embodiments of the present invention are only for illustration and are not intended to limit the scope of the present invention. Replacements or changes of other equivalent components should also be covered by the scope of the patent application of the present invention.

10: Temporarily store the substrate

11: Support the main body

111: Support surface

13: Microstructure layer

131: Microstructure

133: Debondable material layer

30: Chip

31: Chip body

33:Welding pad

Claims (6)

A temporary substrate is used to temporarily fix a plurality of chips. The temporary substrate comprises: a supporting body having a supporting surface; and a microstructure layer connected to the supporting body and located on the supporting surface, and comprising a plurality of microstructures, wherein adjacent microstructures of the plurality of microstructures are arranged at intervals and are used to temporarily fix the plurality of chips. Each of the plurality of chips is attached to at least one of the plurality of microstructures, wherein each of the plurality of chips comprises a chip body and two solder pads connected to the chip body, and each of the plurality of microstructures has a plurality of solder pads connected to the chip body. The bonding surface size of one is smaller than the size of a bonded surface of the pad of each of the multiple chips, and the bonding surface has an adhesive force for connecting the bonded surface, wherein each of the multiple microstructures includes a convex portion protruding from the supporting surface of the supporting body, and the bonding surface is located at the top of the convex portion, wherein each of the multiple microstructures also includes a debondable material layer, the debondable material layer is formed on the surface of the convex portion, and is used to destroy an adhesive force of the debondable material layer after a debonding operation. A temporary substrate as described in claim 1, wherein before the debonding operation, the adhesion force of the debondable material layer is greater than the adhesion force of the bonding surface. The temporary substrate as described in claim 1, wherein the debondable material layer is formed on the surface of the protrusion by a spraying operation, a coating operation or a bonding operation. A temporary substrate as described in claim 1, wherein the debonding material layer includes UV debonding, and the debonding operation is performed through an ultraviolet ray. The temporary substrate as described in claim 1, wherein the supporting body and the microstructure layer are polymer elastic materials. The temporary substrate as described in claim 1 further includes an adhesive layer and a carrier, the adhesive layer connects the supporting body and the carrier, and the rigidity of the carrier is greater than that of the supporting body.

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