Lamination method of interposer for die transfer substrate

Abstract

Embodiments of the present disclosure generally relate to LED pixels and methods of manufacturing LED pixels. The apparatus includes a lamination module. The lamination module includes a polymeric film roller configured to supply a polymeric film to the lamination module, a bottom liner recovery roller, a top liner recovery roller, a cutting mechanism, a substrate source, a transport device system, and a plurality of film rollers. The polymer film includes one or more polymer layers, a top liner, and a bottom liner. The cutting mechanism is configured to cut the one or more polymer layers and the top liner. The cutting mechanism comprises a first blade and a second blade. The space between the first cutting edge and the second cutting edge is smaller than about 10 cm. The substrate source is configured to supply a substrate.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to micro-LED displays and methods of manufacturing micro-LED displays. In particular, the present disclosure relates to lamination of interposers for die transfer substrates. BACKGROUND

[0002] Light emitting diode (LED) panels use an array of LEDs, with individual LEDs providing individually controllable pixel elements. Such LED panels can be used in computers, touch panel devices, personal digital assistants (PDAs), cellular telephones, television monitors, and the like.

[0003] Compared to OLEDs, LED panels using micron-scale LEDs based on III-V semiconductor technology (also referred to as micro-LEDs) would have various advantages, such as higher energy efficiency, brightness, and lifetime, as well as fewer material layers in the display stack, which can simplify manufacturing. However, there are challenges in manufacturing micro-LED panels. Micro-LEDs with different color emission (e.g., red, green, and blue pixels) need to be fabricated on different substrates by separate processes. The manufacturing process requires parallel die transfer from growth of sapphire substrates to integration of thin-film transistor backplanes with high mechanical and illumination yield. Due to the complexity of the die transfer technology, the structural integrity of the interposer and the method of applying the interposer to the support substrate are critical. Defects such as entrapment of air bubbles / particles or insufficient quality of the lamination film (e.g., lack of film uniformity or film edge smoothness) are detrimental to achieving high yield transfer.

[0004] Accordingly, there is a need in the art for a method for laminating an interposer for a die transfer substrate. SUMMARY

[0005] In one embodiment, an apparatus is provided. The apparatus includes a lamination module. The lamination module includes a polymer film roll configured to supply a polymer film to the lamination module, a bottom liner take-up roll, a top liner take-up roll, a cutting mechanism, a substrate source, a conveyance system, and a plurality of film rolls. The polymer film includes one or more polymer layers, a top liner, and a bottom liner. The cutting mechanism is configured to cut the one or more polymer layers and the top liner. The cutting mechanism includes a first blade and a second blade. A space between the first blade and the second blade is less than about 10 cm. The substrate source is configured to supply a substrate.

[0006] In another embodiment, a method is provided. The method includes supplying a polymer film to a lamination module, removing a bottom liner from the polymer film, supplying a substrate to a conveyor system of the lamination module, cutting one or more polymer layers and a top liner with a cutting mechanism, laminating the substrate with the polymer film, and removing the top liner from the polymer film. The polymer film includes the bottom liner, the top liner, and the one or more polymer layers. The cutting mechanism includes a first blade and a second blade. A space between the first blade and the second blade is less than about 10 cm.

[0007] In yet another embodiment, a lamination system is disclosed. The lamination system includes a lamination module, a substrate source, a substrate receiver, and a conveyor system. The lamination module includes a bottom liner take-up roll, a top liner take-up roll, a cutting mechanism configured to cut one or more polymer layers and a top liner, and a plurality of film rolls. The cutting mechanism includes a first blade and a second blade. A space between the first blade and the second blade is less than about 10 cm. The polymer film rolls are configured to supply a polymer film to the lamination module. The polymer film includes the one or more polymer layers, the top liner, and the bottom liner. The substrate source is configured to supply a substrate. BRIEF DESCRIPTION OF DRAWINGS

[0008] For a detailed understanding of the above-mentioned features of the present disclosure, a more complete description can be obtained by reference to the embodiments of the disclosure depicted on the attached drawings. It is to be noted, however, that the appended drawings represent illustrative embodiments of the disclosure and therefore are not to be considered limiting, as the disclosure can admit to other equally effective embodiments.

[0009] Figure 1 is a schematic perspective view of a lamination module according to an embodiment.

[0010] Figure 2 is a schematic cross-sectional view of a polymer film according to an embodiment.

[0011] Figure 3 is a schematic cross-sectional view of a laminated substrate according to an embodiment.

[0012] Figure 4 is a flowchart of a method of laminating a substrate according to an embodiment.

[0013] Figures 5A to 5H is a schematic cross-sectional view of a polymer film roll during a method of laminating a substrate according to an embodiment.

[0014] To facilitate the understanding of this disclosure, like reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment can be beneficially incorporated into other embodiments without further recitation. DETAILED DESCRIPTION

[0015] Embodiments of the present disclosure generally relate to micro-LED displays and methods of manufacturing micro-LED displays. In particular, the present disclosure relates to laminating an interposer for a die transfer substrate. The lamination module includes a polymer film roll configured to supply a polymer film to the lamination module. A bottom liner take-up roll collects a bottom liner of the polymer film, and a top liner take-up roll takes up a top liner of the polymer film. A cutting mechanism is configured to cut one or more polymer layers and the top liner. The cutting mechanism includes a first blade and a second blade. A space between the first blade and the second blade is less than about 10 cm. The substrate is supplied by a substrate source.

[0016] Figure 1 is a schematic perspective view of a lamination system 100. The lamination system 100 includes a substrate source (e.g., a first substrate lifter 104), a polymer film roll 105, a lamination module 101, a conveyance system 106, a substrate support platform 115, and a substrate receiver (e.g., a second substrate lifter 118). The lamination module 101 includes a plurality of film rolls, including a first film roll 107, a second film roll 108, and a third film roll 109, a bottom liner take-up roll 110, a top liner take-up roll 112, and a cutting mechanism 114. The cutting mechanism 114 includes a blade 116 (or one or more blades 116). The first substrate lifter 104 is configured to supply a substrate 102 to an upper side of the conveyance system 106. The conveyance system 106 includes a conveyance belt 119, a first conveyance roll 120, a second conveyance roll 122, and a first conveyance motor 124. The conveyance belt 119 spans between the first conveyance roll 120 and the second conveyance roll 122. The second conveyance roll 122 is coupled to the first conveyance motor 124. The first conveyance motor 124 is configured to rotate the second conveyance roll 122, which is in turn configured to rotate the conveyance belt 119.

[0017] The polymer film roll 105 is configured to supply the polymer film 130 to the lamination module 101. The bottom liner recovery roll 110 is configured to recover the bottom liner 132. The top liner recovery roll 112 is configured to recover the top liner 134. The first film roll 107 and the second film roll 108 are disposed on opposite sides of the conveyor belt 119 on an upper side of the conveyor system 106. The second motor 126 is configured to rotate the second film roll 108. The third film roll 109 and the substrate support platform 115 are disposed on opposite sides of the conveyor belt 119 on the upper side 106A of the conveyor system 106. The first film roll 107, the second film roll 108, the third film roll 109, and the substrate support platform 115 are configured to extrude the polymer film 130 onto the substrate 102. The first film roll 107, the second film roll 108, and the third film roll 109 can comprise a material such as Teflon, polyurethane, other rubber material, or stainless steel. The second substrate lifter 118 is configured to collect the substrate 102 from the conveyor system 106.

[0018] The cutting mechanism 114 can be configured to cut into the polymer film 130. The cutting mechanism 114 can have one or more blades. The cutting mechanism 114 can be a rotary cutting mechanism, an ultrasonic assisted cutting system, or a laser cutting mechanism. The blade of the cutting mechanism 114 pierces one or more polymer film layers of the polymer film 130 (as shown) and a portion of the top liner 134. The blade cuts into about 1% to about 20% of the thickness of the top liner. By cutting into a portion of the top liner 134, the top liner recovery roll 112 maintains the continuous integrity of the top liner 134 to effectively collect the top liner 134 without damaging the top liner 134. Further, by piercing the top liner 134, the cutting mechanism 114 ensures clean separation of the one or more polymer layers from the top liner 134. Figure 2

[0019] The conveyor belt 119 moves in a first direction from the first substrate lifter 104 toward the second substrate lifter 118 on the upper side 106A of the conveyor system 106. The conveyor belt 119 moves in a second direction from the second substrate lifter 118 toward the first substrate lifter 104 on the lower side 106B of the conveyor system 106. The substrate 102 moves in the first direction on the upper side of the conveyor system 106.

[0020] Figure 2 A schematic cross-sectional view of a polymer film 130. The polymer film 130 is supplied from a polymer film roll 105 to a lamination module 101. Figure 3 ​A schematic cross-sectional view of a polymer film 130 for placement on a substrate 102. The polymer film 130 includes a bottom liner 132, one or more polymer layers, and a top liner 134. The one or more polymer layers can include an adhesive layer 242, a support base polymer 244, and a polymer layer 246. The bottom liner 132 and the top liner 134 are configured to prevent the polymer film 130 from sticking to itself when the polymer film 130 is wound onto the polymer film roll 105, the top liner 124, and the bottom liner 132. The adhesive layer 242 is disposed on top of the bottom liner 132. The adhesive layer 242 is configured to adhere the polymer film 130 to the substrate 102. The adhesive layer 242 can include a material such as polyamide, polyester, ethylene vinyl acetate, polyurethane, polyamide epoxy, natural and synthetic rubber, thermoplastic elastomer, polyacrylate, polyvinyl alkyl ether, silicone, polyacrylate, fluoropolymer, or a combination thereof. The support base polymer 244 is disposed on top of the adhesive layer 242. The support base polymer 244 can include a material such as polyamide, polyester, ethylene vinyl acetate, polyurethane, polyamide epoxy, natural and synthetic rubber, thermoplastic elastomer, polyacrylate, polyvinyl alkyl ether, silicone, polyacrylate, fluoropolymer, pressure sensitive adhesive, polyimide, PPS, or a combination thereof. The polymer layer 246 is disposed on top of the support base polymer 244. The polymer layer 246 includes a thermal release tape, a UV release tape, a light and laser release tape, or a combination thereof. The top liner 134 is disposed on top of the polymer layer 246.

[0021] Figure 4 A flowchart of a method 400 of laminating a substrate 102. Figures 5A to 5H A schematic cross-sectional view of a polymer film 130 during the method 400 of laminating a substrate 102. At operation 402, the polymer film 130 is supplied to the lamination module 101. The polymer film 130 is fed from the polymer film roll 105 to the lamination module 101. As shown, the polymer film 130 includes a bottom liner 132, a top liner 134, and one or more polymer layers. The one or more polymer layers can include an adhesive layer 242, a support base polymer 244, and a polymer layer 246. Figure 2

[0022] At operation 404, the bottom liner 132 is removed from the polymer film 130. The bottom liner 132 is removed using the bottom liner take-up roll 110. By removing the bottom liner 132, the one or more polymer layers (e.g., the adhesive layer 242) become exposed.

[0023] ​At operation 406, substrate 102 is supplied to conveyor system 106 of laminating module 101. Substrate 102 is supplied from first substrate lifter 104 to conveyor system 106. Conveyor system 106 includes conveyor belt 119, first conveyor roller 120, second conveyor roller 122, and first conveyor motor 124. First conveyor motor 124 rotates second conveyor roller 122 to move conveyor belt 119 along upper side 106A of conveyor system 106 in a first direction and along lower side 106B of conveyor system 106 in a second direction. The first direction travels from first substrate lifter 104 to second substrate lifter 118, and the second direction travels from second substrate lifter 118 to first substrate lifter 104. Substrate 102 is placed on conveyor belt 119 of conveyor system 106 and travels in the first direction.

[0024] At operation 408, such as Figure 5A As shown, the polymer film 130 is cut using a cutting mechanism 114. The cutting mechanism 114 may have one or more cutting edges. The cutting mechanism 114 may be a rotary cutting mechanism, an ultrasonic-assisted cutting system, or a laser cutting mechanism. Figure 5A As shown, the cutting mechanism 114 has a first blade 551 and a second blade 552. The blades are spaced apart by a distance x. The distance x is less than about 10 cm, such as less than about 1 cm, such as 0 cm (e.g., from a single cut by a single blade). The blades pierce a portion of the adhesive layer 242, the supporting substrate polymer 244, the polymer layer 246, and the top liner 134. The blades cut into about 1% to about 20% of the thickness of the top liner 134. By piercing a portion of the top liner 134, the continuity and integrity of the top liner 134 are maintained while allowing clear separation of the adhesive layer 242, the supporting substrate polymer 244, and the polymer layer 246 from the top liner 134.

[0025] At operation 410, such as Figure 5BAs shown, the substrate 102 is laminated with the polymer film 130. The first film roller 107 directs the polymer film 130 to the substrate 102 on the conveyor belt 119. The first film roller 107 is positioned above the conveyor belt 119 on the upper side 106A of the conveyor system 106, and the second film roller 108 is positioned below the conveyor belt 119 on the upper side 106A of the conveyor system 106, opposite the first film roller 107. The exposed adhesive layer 242 is pressed against the substrate 102 using the first film roller 107 and the second film roller 108. The third film roller 109 and the substrate support platform 115 are positioned behind the first film roller 107 and the second film roller 108 in the first direction. The third film roller 109 and the substrate support platform 115 continue to press the adhesive layer 242 against the substrate 102 to eliminate defects at the adhesive interface. The top liner 134 prevents the polymer layer of the polymer film 130 from sticking to the first film roller 107, the second film roller 108, the third film roller 109, and the substrate support platform 115. As Figure 5B As shown, the polymer film 130 can have a gap y from the edge of the substrate 102. The distance x between the cutting blades is maintained to allow for the gap y, while accounting for the tapered geometry of the blades. The gap y is less than about 10 cm, such as less than about 1 cm, such as about 0 cm. A portion of the adhesive layer 242, the support base polymer 244, and the polymer layer 246 is not pressed against the substrate 102 (e.g., a portion of the adhesive layer 242, the support base polymer 244, and the polymer layer 246 is in a gap from the leading substrate 102 to the trailing substrate 102). The gap between the leading substrate 102 and the trailing substrate 102 can be equal to the distance x between the first blade 551 and the second blade 552.

[0026] At operation 412, the top liner 134 is removed from the polymer film 130. A doctor blade can be used to peel the top liner 134 from the polymer film 130. The top liner 134 is recycled using the top liner recycling roller 112. The portion of the adhesive layer 242, the support base polymer 244, and the polymer layer 246 that is not laminated to the substrate 102 can also be recycled by the top liner recycling roller 112. Since the top liner 134 is not cut during operation 408, the top liner recycling roller 112 maintains the continuous integrity of the top liner 134 to effectively collect the top liner 134 without damaging the top liner 134. By removing the bottom liner 132, the polymer layer 246 becomes exposed to further processing.

[0027] At operation 414, as Figure 5CAs shown, a plurality of LEDs 510 are coupled to the polymer film 130. The LED source substrate 505 has a plurality of LEDs 510 formed or grown thereon. Although only 2 LEDs 510 are shown, it should be understood that the substrate can have hundreds, thousands, millions, or more LEDs formed thereon, and can be of any size, as the present technology can encompass micro-LEDs as well as any other type of LED structure. The LED source substrate 505 can be any substrate on which structures can be formed, such as a silicon material, an aluminum material (including sapphire), or any other material that can be used in display or semiconductor manufacturing. The LEDs 510 can have any shape or structure, and can be formed as single color LED structures, or specific RGB or other LED structures. As illustrated, the LED structures can have a stepped profile as illustrated, or any other structure. One or more contacts or one or more contacts can extend from the LEDs 510. For example, a first contact (such as an N contact) and a second contact (such as a P contact) can extend from a first surface of the LED. In embodiments encompassed by the present technology, the contacts can be made of any metal, alloy, or conductive material. The contacts can be formed to be substantially similar in height, but can vary between LEDs formed across the substrate.

[0028] At operation 416, as Figure 5D shown, the LED source substrate 505 is separated from the LEDs 510. After the first coupling material is sufficiently coated and / or cured, the LED source substrate 505 can be separated from the plurality of fabricated LEDs 510. Any number of separation techniques can be performed, including mechanical separation and energy enhanced separation. As one non-limiting example, in some embodiments, a laser lift-off process can be performed. As noted above, although the LED source substrate 505 can be of any number of materials, in some embodiments, the LED source substrate 505 can be sapphire. The separation process can include directing a laser through a backside of the LED source substrate 505 to separate the plurality of fabricated LEDs 510 from the LED source substrate 505.

[0029] At operation 418, as Figure 5EAs shown, the transfer substrate 535 is coupled to the plurality of LEDs 510. Once the LED source substrate 505 has been separated from the plurality of LEDs 510, the plurality of manufactured LEDs 510 can be inverted with respect to the polymer film 130. The transfer substrate 525 can include a coupling material 240 that can extend along the second surface or backside of each of the plurality of LEDs 510 and can extend between the transfer substrate 535 and the LEDs 510. The transfer substrate 535 can be or include any of the materials previously described, including glass, silicon-containing materials, polymer or plastic materials, or any other substrate on which semiconductor or display processing can occur. The transfer substrate 535 can be a material that is thermally compatible with the backplane substrate.

[0030] At operation 420, as shown, the polymer film 130 can be separated from the transfer substrate 535, which can expose the metal contacts on the LEDs 510. The LEDs 510 can remain on the coupling material 540 associated with the transfer substrate 535. Figure 5F

[0031] At operation 422, as shown, the plurality of LEDs 510 are coupled to a backplane 550. The bonding operation can be performed after the polymer film 130 is separated from the transfer substrate 535. The transfer substrate 535 can be used to align the LEDs 510 with the backplane 550 of the display, and it can be formed on a substrate 545. The contacts of the LEDs 510 can be aligned with corresponding contacts of the backplane 550. A bonding process can be performed, which can include forming a eutectic bond between the contact materials, if different, or a solid connection between the contacts in any number of bonding operations. As one non-limiting example, the LED contacts can be or include indium, which can melt at about 156°C by applying heat to the substrate 545, and the contact connection can be heated above the melting point of the contacts, which can bond the contacts. As previously described, this can cause both the backplane substrate 545 and the transfer substrate 535 to be heated. Based on the coefficient of thermal expansion of the substrate materials, the substrates can expand to different degrees, which can affect the alignment during the bonding process and can reduce the yield of the LED connections. Similarly, pressure can be applied to one or both of the substrates during the bonding process, which can reduce the melting temperature of the contact materials and can ensure that the bonding can occur below the release onset temperature of the second coupling material. Figure 5G At operation 424, the plurality of LEDs 510 are separated from the transfer substrate 535. The transfer substrate 235 can be removed from the plurality of LEDs 510 by releasing the coupling material 540 from the second surface or backside of the LEDs 510.

[0032]

[0033] ​​In summary, the lamination module includes a roll of polymer film configured to supply the lamination module with a polymer film. A bottom liner take-up roll collects a bottom liner of the polymer film, and a top liner take-up roll collects a top liner of the polymer film. A cutting mechanism is configured to cut one or more polymer layers and a portion of the top liner. By piercing a portion of the top liner, the continuous integrity of the top liner is maintained while allowing the polymer film to be cleanly separated from the top liner.

[0034] While the foregoing is directed to implementations of the present disclosure, other and further implementations may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A lamination module, comprising: a bottom liner take-up roll; a top liner take-up roll; and a cutting mechanism configured to cut one or more polymer layers of a polymer film supplied by a polymer film roll and a top liner, and wherein the cutting mechanism comprises a first blade and a second blade, wherein a space between the first blade and the second blade is less than about 10 cm.

2. The lamination module of claim 1, wherein the cutting mechanism is configured to cut about 1% to about 20% of a thickness of the top liner.

3. The lamination module of claim 1, wherein a plurality of film rolls are configured to laminate a substrate with the polymer film.

4. The lamination module of claim 3, wherein the plurality of film rolls comprises: a first film roll; a second film roll; and a third film roll.

5. The lamination module of claim 3, wherein the first blade and the second blade have a tapered geometry, wherein the tapered geometry and the space between the first blade and the second blade are configured to allow a gap between an edge of the substrate and the polymer film.

6. The lamination module of claim 1, wherein the one or more polymer layers comprise an adhesive layer, a support base polymer, and a polymer layer.

7. The lamination module of claim 1, wherein the cutting mechanism comprises a rotary cutting mechanism, an ultrasonic assisted cutting system, or a laser cutting mechanism.

8. A method of laminating a substrate, comprising: supplying a polymer film to a lamination module, wherein the polymer film comprises a bottom liner, a top liner, and one or more polymer layers; removing the bottom liner from the polymer film; supplying a substrate to a conveyor system of the lamination module; cutting the one or more polymer layers and the top liner with a cutting mechanism, wherein the cutting mechanism comprises a first blade and a second blade, wherein a space between the first blade and the second blade is less than about 10 cm; laminating the substrate with the polymer film; and removing the top liner from the polymer film. cutting about 1% to about 20% of a thickness of the top liner with the cutting mechanism.

10. The method of claim 8, wherein a plurality of film rolls are configured to laminate the substrate with the polymer film.

9. The method of claim 8, further comprising:

11. The method of claim 8, wherein the first blade and the second blade have a tapered geometry, wherein the tapered geometry and a space between the first blade and the second blade are configured to allow a gap between an edge of the substrate and the polymer film.

12. The method of claim 8, wherein the one or more polymer layers comprise an adhesive layer, a support base polymer, and a polymer layer.

13. The method of claim 8, wherein a gap is less than about 10 cm.

14. The method of claim 8, wherein the cutting mechanism comprises a rotary cutting mechanism, an ultrasonic assisted cutting system, or a laser cutting mechanism.

15. A lamination system, comprising: a lamination module, comprising: a bottom liner take-up roll; a top liner take-up roll; and a cutting mechanism configured to cut one or more polymer layers of a polymer film supplied by a polymer film roll and a top liner, and wherein the cutting mechanism comprises a first blade and a second blade, wherein a space between the first blade and the second blade is less than about 10 cm. ​ a cutting mechanism configured to cut one or more polymer layers and the top liner, the cutting mechanism comprising a first blade and a second blade, wherein a space between the first blade and the second blade is less than about 10 cm; and a plurality of film rollers; a polymer film roller configured to supply a polymer film to the lamination module, wherein the polymer film comprises one or more polymer layers, a top liner, and a bottom liner; a substrate source configured to supply a substrate; a substrate receiver; and a conveyance system.

16. The lamination system of claim 15, wherein the cutting mechanism is configured to cut about 1% to about 20% of a thickness of the top liner.

17. The lamination system of claim 15, wherein the plurality of film rollers are configured to laminate a substrate with the polymer film.

18. The lamination system of claim 17, wherein the first blade and the second blade have a tapered geometry, wherein the tapered geometry and the space between the first blade and the second blade are configured to allow a gap between an edge of the substrate and the polymer film.

19. The lamination system of claim 15, wherein the one or more polymer layers comprise an adhesive layer, a support base polymer, and a polymer layer.

20. The lamination system of claim 15, wherein the cutting mechanism comprises a rotary cutting mechanism, an ultrasonic assisted cutting system, or a laser cutting mechanism.

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