Method of laminating an interposer for die transfer substrates

Abstract

The embodiments disclosed herein generally relate to LED pixels and methods for manufacturing LED pixels. The apparatus includes a lamination module. The lamination module includes a polymer film roller configured to supply a polymer film to the lamination module, a bottom liner recovery roller, a top liner recovery roller, a cutting mechanism, a substrate source, a conveyor 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 one or more polymer layers and the top liner. The cutting mechanism includes a first blade and a second blade. The space between the first blade and the second blade is less than about 10 cm. The substrate source is configured to supply a substrate.

Description

Technical Field

[0001] The embodiments of this disclosure generally relate to micro LED displays and methods for manufacturing micro LED displays. Specifically, this disclosure relates to laminating an interposer for a die transfer substrate. Prior Technology

[0002] Light-emitting diode (LED) panels use LED arrays, with each LED providing an individually controllable pixel element. These LED panels are used in computers, touch panel devices, personal digital assistants (PDAs), cellular phones, television monitors, and the like.

[0003] Compared to OLEDs, LED panels using micron-sized LEDs based on III-V semiconductor technology (also known as micro-LEDs) offer various advantages, such as higher energy efficiency, brightness, and lifespan, as well as fewer material layers in the display stack, which simplifies manufacturing. However, manufacturing micro-LED panels presents challenges. Micro-LEDs with different color emissions (e.g., red, green, and blue pixels) need to be manufactured on different substrates via separate processes. The manufacturing process requires parallel die transfer from growing the sapphire substrate to integrating the thin-film transistor backplane, resulting in high mechanical and lighting throughput. Due to the complexity of die transfer technology, the structural integrity of the interposer and the method of applying the interposer to the supporting substrate are crucial. Defects such as trapped bubbles / particles or insufficient lamination quality (e.g., lack of film uniformity or film edge smoothness) hinder high-throughput transfer.

[0004] Therefore, there is a need in the art for a method for laminating an interposer for a bare die transfer substrate. Summary of the Invention

[0005] In one embodiment, an apparatus is provided. The apparatus includes a lamination module. The lamination module includes a polymer film roller configured to supply a polymer film to the lamination module, a bottom liner recovery roller, a top liner recovery roller, a cutting mechanism, a substrate source, a conveyor 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 one or more polymer layers and the top liner. The cutting mechanism includes a first blade and a second blade. The 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 using a cutting mechanism, laminating the substrate to the polymer film, and removing the top liner from the polymer film. The polymer film includes a bottom liner, a top liner, and one or more polymer layers. The cutting mechanism includes a first blade and a second blade. The space between the first blade and the second blade is less than about 10 cm.

[0007] In 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 recovery roller, a top liner recovery roller, a cutting mechanism configured to cut one or more polymer layers and a top liner, and a plurality of film rollers. The cutting mechanism includes a first blade and a second blade. The space between the first blade and the second blade is less than about 10 cm. The polymer film rollers are configured to supply a polymer film to the lamination module. The polymer film includes one or more polymer layers, a top liner, and a bottom liner. The substrate source is configured to supply a substrate. Simple Explanation of the Diagram

[0008] To gain a more detailed understanding of the features described above in this disclosure, a more specific description of the disclosure, as briefly summarized above, can be obtained by referring to the embodiments of the disclosure illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate embodiments of the disclosure and should therefore not be considered as limiting the scope of the disclosure, as other equally effective embodiments are permissible.

[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 the polymer film according to the 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 for laminating a substrate according to an embodiment.

[0013] Figures 5A to 5H are schematic cross-sectional views of the polymer film roller during the method of laminating a substrate according to the embodiment.

[0014] For ease of understanding, the same component symbols are used as much as possible to represent common components in the figures. It is conceivable that components and features of one embodiment can be advantageously incorporated into other embodiments without further explanation. Implementation

[0015] The embodiments of this disclosure generally relate to micro-LED displays and methods for manufacturing micro-LED displays. Specifically, this disclosure relates to laminating an interposer for a die transfer substrate. A lamination module includes a polymer film roller configured to supply a polymer film to the lamination module. A bottom liner recovery roller collects the bottom liner of the polymer film, and a top liner recovery roller collects the 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. The space between the first blade and the second blade is less than about 10 cm. The substrate is supplied from 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 roller 105, a lamination module 101, a conveyor 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 rollers, including a first film roller 107, a second film roller 108, and a third film roller 109, a bottom liner recovery roller 110, a top liner recovery roller 112, and a cutting mechanism 114. The cutting mechanism 114 includes blades 116 (or one or more blades 116). The first substrate lifter 104 is configured to supply a substrate 102 to the upper side of the conveyor system 106. The conveyor system 106 includes a conveyor belt 119, a first conveyor roller 120, a second conveyor roller 122, and a first conveyor motor 124. The conveyor belt 119 spans between the first conveyor roller 120 and the second conveyor roller 122. The second conveyor roller 122 is coupled to the first conveyor motor 124. The first conveyor motor 124 is configured to rotate the second conveyor roller 122, which in turn is configured to rotate the conveyor belt 119.

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

[0018] Cutting mechanism 114 can be configured to cut into polymer film 130. Cutting mechanism 114 can have one or more blades. Cutting mechanism 114 can be a rotary cutting mechanism, an ultrasonic-assisted cutting system, or a laser cutting mechanism. The blades of cutting mechanism 114 pierce one or more polymer film layers (as shown in Figure 2) and a portion of top liner 134 of polymer film 130. The blades cut into about 1% to about 20% of the thickness of top liner. By cutting into a portion of top liner 134, the continuity and integrity of top liner 134 is maintained for top liner recovery roller 112 to effectively collect top liner 134 without damaging it. Furthermore, by piercing top liner 134, cutting mechanism 114 ensures clean separation of one or more polymer layers from top liner 134.

[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 is a schematic cross-sectional view of the polymer film 130. The polymer film 130 is supplied from the polymer film roller 105 to the lamination module 101. Figure 3 is a schematic cross-sectional view of the polymer film 130 disposed on the 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 may include an adhesive layer 242, a supporting substrate 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 adhering to itself when it is wound onto the polymer film roller 105, the top liner 134, and the bottom liner 132. The adhesive layer 242 is disposed on the bottom liner 132. The adhesive layer 242 is configured to adhere the polymer film 130 to the substrate 102. Adhesive layer 242 may include materials such as polyamide, polyester, ethylene vinyl acetate, polyurethane, polyamide epoxy resin, natural and synthetic rubber, thermoplastic elastomer, polyacrylate, polyethylene alkyl ether, silicone resin, polyacrylate, fluoropolymer, or combinations thereof. Supporting substrate polymer 244 is disposed on adhesive layer 242. Supporting substrate polymer 244 may include materials such as polyamide, polyester, ethylene vinyl acetate, polyurethane, polyamide epoxy resin, natural and synthetic rubber, thermoplastic elastomer, polyacrylate, polyethylene alkyl ether, silicone resin, polyacrylate, fluoropolymer, pressure-sensitive adhesive, polyimide, PPS, or combinations thereof. Polymer layer 246 is disposed on supporting substrate polymer 244. Polymer layer 246 includes heat release strips, UV release strips, light and laser release strips, or combinations thereof. Top liner 134 is disposed on polymer layer 246.

[0021] Figure 4 is a flowchart of method 400 for laminating substrate 102. Figures 5A to 5H are schematic cross-sectional views of the polymer film 130 during method 400 for laminating substrate 102. At operation 402, the polymer film 130 is supplied to lamination module 101. The polymer film 130 is fed from polymer film roller 105 to lamination module 101. As shown in Figure 2, 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 may include an adhesive layer 242, a supporting substrate polymer 244, and a polymer layer 246.

[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 recovery roller 110. By removing the bottom liner 132, one or more polymer layers (e.g., adhesive layer 242) become exposed.

[0023] At operation 406, substrate 102 is supplied to conveyor system 106 of lamination module 101. Substrate 102 is supplied to conveyor system 106 from first substrate lifter 104. 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, as shown in Figure 5A, the polymer film 130 is cut using a cutting mechanism 114. The cutting mechanism 114 may have one or more blades. The cutting mechanism 114 may be a rotary cutting mechanism, an ultrasonic-assisted cutting system, or a laser cutting mechanism. As shown in Figure 5A, 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, as shown in Figure 5B, a polymer film 130 is laminated onto a substrate 102. A first film roller 107 guides the polymer film 130 onto the substrate 102 on a 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 a second film roller 108 is positioned below the conveyor belt 119 on the upper side 106A of the conveyor system 106, opposite to 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. A third film roller 109 and a substrate support platform 115 are positioned in a first direction after the first film roller 107 and the second film roller 108. 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 adhering to the first film roller 107, the second film roller 108, the third film roller 109, and the substrate support platform 115. As shown in Figure 5B, the polymer film 130 may have a gap y with the edge of the substrate 102. The distance x between the cutting blades is maintained to allow for the gap y, while taking into account 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 supporting substrate polymer 244, and the polymer layer 246 is not pressed against the substrate 102 (e.g., a portion of the adhesive layer 242, the supporting substrate polymer 244, and the polymer layer 246 is in the gap from the guide substrate 102 to the trailing substrate 102). The gap between the guide substrate 102 and the trailing substrate 102 may 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 scraper can be used to peel the top liner 134 from the polymer film 130. The top liner 134 is recovered using the top liner recovery roller 112. Unlaminated portions of the adhesive layer 242, the supporting substrate polymer 244, and the polymer layer 246 onto the substrate 102 can also be recovered by the top liner recovery roller 112. Since the top liner 134 is not cut during operation 408, the top liner recovery roller 112 maintains the continuity and integrity of the top liner 134 to effectively collect it without damaging it. By removing the bottom liner 132, the polymer layer 246 becomes exposed to further processing.

[0027] At operation 414, as shown in Figure 5C, a plurality of LEDs 510 are coupled to polymer film 130. LED source substrate 505 has a plurality of LEDs 510 formed or grown thereon. Although only two 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 this technology can encompass microLEDs as well as any other type of LED structure. LED source substrate 505 can be any substrate on which structures can be formed, such as silicon, aluminum (including sapphire), or any other material that can be used in display or semiconductor manufacturing. LEDs 510 can have any shape or structure and can be formed as a monochrome LED structure, or a specific RGB or other LED structure. As illustrated, the LED structure can have a stepped profile as illustrated, or any other structure. One or more contacts can be formed or one or more contacts can extend from 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 the embodiments covered by this technology, the contacts can be made of any metal, alloy, or conductive material. The contacts can be formed to a generally similar height, but may vary between LEDs formed across the substrate.

[0028] At operation 416, as shown in Figure 5D, the LED source substrate 505 is separated from the LED 510. After sufficient coating and / or curing of the first coupling material, the LED source substrate 505 can be separated from the plurality of manufactured LEDs 510. Any number of separation techniques can be performed, including mechanical separation and energy-enhanced separation. As a non-limiting example, in some embodiments, a laser stripping process can be performed. As mentioned above, although the LED source substrate 505 can be any number of materials, in some embodiments, the LED source substrate 505 can be sapphire. The separation process may include guiding a laser through the back side of the LED source substrate 505 to separate the plurality of manufactured LEDs 510 from the LED source substrate 505.

[0029] At operation 418, as shown in Figure 5E, a transfer substrate 535 is coupled to a 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 relative to the polymer film 130. The transfer substrate 535 may include a coupling material 540 that may extend along a second surface or back side of each of the plurality of LEDs 510 and may extend between the transfer substrate 535 and the LEDs 510. The transfer substrate 535 may 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 may occur. The transfer substrate 535 may be a material thermally compatible with the backplane substrate.

[0030] At operation 420, as shown in Figure 5F, the polymer film 130 can be separated from the transfer substrate 535, thus exposing the metal contacts on the LED 510. The LED 510 can be held on the coupling material 540 associated with the transfer substrate 535.

[0031] At operation 422, as shown in Figure 5G, a plurality of LEDs 510 are coupled to a backplane 550. After the polymer film 130 separates from the transfer substrate 535, a bonding operation can be performed. 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 may include forming a eutectic bond between contact materials (if different) or a solid connection between contacts in any number of bonding operations. As a non-limiting example, the LED contacts may be indium or include indium, which can be melted at approximately 156°C by applying heat to the substrate 545, and the contact connection can be heated above the melting point of the contacts, thus bonding the contacts. As previously mentioned, this may cause both the backplane substrate 545 and the transfer substrate 535 to be heated. Based on the coefficient of thermal expansion of the substrate material, the substrate may expand to varying degrees, which can affect alignment during the bonding process and potentially reduce the yield of LED connections. Similarly, pressure can be applied to one or both substrates during the bonding process, which can lower the melting temperature of the contact material and ensure that bonding can be performed below the release initiation temperature of the second coupling material.

[0032] At operation 424, the plurality of LEDs 510 are separated from the transfer substrate 535. The transfer substrate 535 can be removed from the plurality of LEDs 510 by releasing coupling material 540 from the second surface or back side of the LEDs 510.

[0033] In summary, the lamination module includes a polymer film roller configured to supply a polymer film to the lamination module. A bottom liner recovery roller collects the bottom liner of the polymer film, and a top liner recovery roller collects the 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 continuity and integrity of the top liner are maintained while allowing clear separation of the polymer film from the top liner.

[0034] Although the foregoing embodiments pertain to this disclosure, other and further embodiments may be designed without departing from their basic scope, the scope of which is determined by the following claims.

[0035] 100: Lamination System 101: Lamination Module 102:Substrate 104: First substrate lifter 105: Polymer film roller 106: Conveyor System 106A: Upper side 106B: Lower side 107: First film roller 108: Second film roller 109: Third film roller 110: Bottom Liner Recycling Roller 112: Top Liner Recycling Roller 114: Cutting Mechanism 115: Substrate support platform 116: Blade 118: Second substrate lifter 119: Conveyor Belt 120: First conveyor roller 122: Second conveyor roller 124: First conveyor motor 126: Second Motor 130: Polymer membrane 132: Bottom Lining 134: Top Lining 242: Adhesive layer 244: Supporting substrate polymer 246: Polymer layer 400: Method 402: Operation 404: Operation 406: Operation 408: Operation 410: Operation 412: Operation 414: Operation 416: Operation 418: Operation 420: Operation 422: Operation 424: Operation 505: LED source substrate 510: LED 535: Transmission board 540: Coupling material 545:Substrate 550: Backplate 551: First Blade 552: Second Blade x: distance y: gap

[0036] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A laminating module, comprising: A bottom-lined recycling roller; A top-lined recycling roller; A cutting mechanism including a blade configured to cut one or more polymer layers and a top liner of a polymer film supplied by a polymer film roller, such that when a substrate is disposed in the lamination module, a gap exists between an edge of the substrate and the polymer film; and a first film roller configured to guide a polymer film to the cutting mechanism.

2. The lamination module as described in claim 1, wherein the blade is configured to cut about 1% to about 20% of the thickness of the top liner.

3. The laminated module as described in claim 1, wherein the gap is less than about 10 cm.

4. The lamination module as claimed in claim 1, wherein the blade has a tapered geometry, wherein the tapered geometry is configured to allow the gap.

5. The laminated module as claimed in claim 1, wherein the one or more polymer layers include an adhesive layer, a supporting substrate polymer, and a polymer layer.

6. The lamination module as claimed in claim 1, wherein the cutting mechanism includes a rotary cutting mechanism, an ultrasonic-assisted cutting system, or a laser cutting mechanism.

7. A method of laminating a substrate, comprising the steps of: supplying a polymer film to a laminating assembly, wherein the polymer film includes 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 laminating assembly using a first film roller; cutting the one or more polymer layers and the top liner using a cutting mechanism including a blade while the one or more polymer layers and the top liner are supplied to the laminating assembly by the first film roller; laminating the substrate to the polymer film; and removing the top liner from the polymer film.

8. The method as described in claim 7 further includes the step of using the cutting mechanism to cut about 1% to about 20% of the thickness of the top lining.

9. The method of claim 7, wherein a plurality of film rollers are configured to laminate the substrate to the polymer film, the plurality of film rollers comprising: The first film roller is located on a first side of the conveyor system; A second film roller located on a second side of the conveyor system opposite to the first film roller; and a third film roller.

10. The method as described in claim 7, wherein a gap between an edge of the substrate and the polymer film is less than about 10 cm.

11. The method as described in claim 10, wherein the cutting edge has a tapered geometry configured to allow the gap.

12. The method as described in claim 7, wherein the one or more polymer layers comprise an adhesive layer, a supporting substrate polymer, and a polymer layer.

13. The method as described in claim 7, wherein the cutting mechanism comprises a rotary cutting mechanism, an ultrasonic-assisted cutting system, or a laser cutting mechanism.

14. A lamination system, comprising: A laminating assembly includes: a cutting mechanism including a blade and configured to cut one or more polymer layers and a top liner of a polymer film supplied by a polymer film roller; and a first film roller among a plurality of film rollers configured to guide a polymer film to the cutting mechanism; a polymer film roller configured to supply the polymer film to the laminating assembly, wherein the polymer film includes the one or more polymer layers, the top liner, and a bottom liner; a substrate source configured to supply a substrate; a substrate receiver; and a conveyor system.

15. The lamination system as claimed in claim 14, wherein the cutting mechanism is configured to cut about 1% to about 20% of the thickness of the top liner.

16. The lamination system as claimed in claim 14, wherein the plurality of film rollers are configured to laminate a substrate to the polymer film.

17. The lamination system as claimed in claim 16, wherein the blade has a tapered geometry configured to allow a gap between an edge of the substrate and the polymer film.

18. The lamination system as described in claim 17, wherein the gap is less than about 10 cm.

19. The lamination system as claimed in claim 14, wherein the cutting mechanism comprises a rotary cutting mechanism, an ultrasonic-assisted cutting system, or a laser cutting mechanism.

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