Decomposable polymer in microsolid printing process

Abstract

The present disclosure relates to integrating micro-semiconductor devices into a system substrate using a decomposable polymer. In at least one implementation, a method includes metalizing a substrate by mixing metal powders in the decomposable polymer under light or temperature; patterning using a printing process; and decomposing the decomposable polymer to sinter the metal powders.

Description

Attorney Docket No. - VR13P003PCT (VR13-000155PL01) DECOMPOSABLE POLYMER IN MICROSOLID PRINTING PROCESS CLAIM OFPRIORITY

[0001] This application claims priority to U.S. Provisional Application No.63 / 575,512 filed April 05, 2024, titled “DECOMPOSABLE POLYMER IN MICROSOLID PRINTING PROCESS,” which is incorporated by reference in its entirety. SUMMARY

[0001] The present disclosure relates to a method of integrating microdevices into a system substrate using a decomposable polymer in a MicroSolid printing process. In at least one embodiment, the method includes metalizing a substrate by mixing metal powders in decomposable polymers under light or temperature, patterning using a printing process and decomposing the polymer at high temperatures, to sinter the metal powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Material described herein is illustrated by way of embodiment and not by way of limitation in accompanying Figures. For simplicity and clarity of illustration, elements illustrated in Figures are not necessarily drawn to scale. For embodiment, dimensions of some elements may be exaggerated relative to other elements for clarity. Also, various physical features may be represented in their simplified “ideal” forms and geometries for clarity of discussion, but it is nevertheless to be understood that practical implementations may approximate illustrated ideals. For embodiment, smooth surfaces and square intersections may be drawn in disregard of finite roughness, corner-rounding, and imperfect angular intersections characteristic of structures formed by nanofabrication techniques. Further, where considered appropriate, reference labels have been repeated among Figures to indicate corresponding or analogous elements.

[0003] The foregoing and other advantages of the disclosure will become apparent upon reading the following detailed description and upon reference to the drawings.

[0004] Figure 1A is an illustration of a structure where microdevice with pads are positioned above a decomposable material for bonding, in at least one embodiment.

[0005] Figure 1B is an illustration of a structure of Figure 1A, where microdevices are bonded to top of the pads within the decomposable material, in at least one embodiment. 2Attorney Docket No. - VR13P003PCT (VR13-000155PL01)

[0006] Figure 1C is an illustration of a structure of Figure 1C, where microdevices are subjected bonding process at pressures and temperatures that can decompose the decomposable material and couple the microdevices to the system substrate, in at least one embodiment.

[0007] Figure 1D is an illustration of a structure where microdevice with pads are electrically coupled to conductive bumps as an embodiment of direct bonding.

[0008] Figure 1E is an illustration of structure in Figure 1D, following removal of release layer, in at least one embodiment.

[0009] Figure 1F is an illustration of a structure where microdevice with pads are electrically coupled to bonding pads that are surrounded by a multi-layered stack of decomposable materials, in at least one embodiment.

[0010] Figure 1G is an illustration of a structure in Figure 1F following a process to decompose the multi-layered stack of decomposable materials, in at least one embodiment.

[0011] Figure 1H illustrates an enhanced cross section of structure in Figure 1F through a line A-A’, in at least one embodiment.

[0012] Figure 1I illustrates an enhanced cross section of structure in Figure 1F through a line A- A’, in at least one embodiment.

[0013] Figure 1J is an illustration of a structure that includes a dielectric between decomposable material and conductive pads, in at least one embodiment.

[0014] Figure 2 illustrates a flow diagram of a method to transfer microdevices from a substrate, in at least one embodiment.

[0015] Figure 3 illustrates a cartridge structure with thermally decomposable polymer (TDP) as a release layer, in at least one embodiment.

[0016] Figure 4 illustrates the cartridge structure in Figure 2 following a process of decomposition of the release layer.

[0017] Figure 5 illustrates a microdevice integrated in a cartridge using LGT material for cartridge development, in at least one embodiment.

[0018] Figure 6 illustrates a microdevice integrated in a cartridge using LGT material for cartridge development, in at least one embodiment.

[0019] Figure 7 illustrates a cross section of structure in Figure 5, where a decomposable layer comprising a bilayer stack, in at least one embodiment. 3Attorney Docket No. - VR13P003PCT (VR13-000155PL01)

[0020] Figure 8 illustrates a cross section of structure in Figure 6, where a decomposable layer comprising a bilayer stack, in at least one embodiment.

[0021] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of embodiment in the drawings and will be described in detail herein. It should be understood, however, that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of a disclosure as defined by the appended claims. DETAILED DESCRIPTION

[0022] At least one embodiment describes a method of integrating micro-semiconductor devices into a system substrate using a decomposable polymer in a MicroSolid printing process. Integrating micro-semiconductor devices into a system substrate provides opportunities to create different functionalities and applications, such as microLED displays and microsensors. In at least one embodiment, MicroSolid printing process involves developing and fabricating microdevices on a native substrate and moving them selectively or en masse from the native substrate into a system substrate.

[0023] In at least one embodiment, before or after transferring microdevices into the system substrate metallization formation, in the form of pads, is needed to enable control. In at least one embodiment, electrically connecting microdevices to the system substrate may require bonding materials with electrical connectivity. In at least one embodiment, a cartridge substrate is implemented to hold the microdevices and release them selectively into the system substrate through pads. Building different components related to microdevice integration into the system substrate using thermal-decomposable polymers are discussed herein. In at least one embodiment, the thermal-decomposable polymer turns to vapor or gas at a nominal temperature.

[0024] In at least one embodiment, metallization on a large substrate can limit potential of printing production of optoelectronic array devices such as displays and sensors. In at least one embodiment, metallization is done in large-area high-vacuum chambers, followed by patterning. In at least one embodiment, metal powders can be mixed in polymers that can decompose under light or effect of temperature. Printing processes such as inkjet or spray printing can develop the mixture of polymer and metal powder in desired patterns. After formation of desired patterns, the polymer can be decomposed at high temperatures, and the metal powder may be sintered. In at 4Attorney Docket No. - VR13P003PCT (VR13-000155PL01) least one embodiment, two or more metals can be used to achieve low-temperature sintering and enable high conductivity. In at least one embodiment, silver and indium can be added to a composable polymer solution.

[0025] In at least one embodiment, decomposable polymers can be mixed with conductive nanoparticles to facilitate electrical and mechanical bonding between microdevices and a system substrate. In at least one embodiment, materials can be formed in bump format on a receiver substrate. In at least one embodiment, the microdevices can be positioned and bonded to the bumps at a temperature that is the same or higher than a glass transition temperature of polymers utilized. In at least one embodiment, after microdevices are transferred, pressure and / or temperature can be applied to decompose the polymer, leaving conductive nanoparticles to form an electrical and mechanical connection between the device and the system substrate. In at least one embodiment, the nanoparticles can be metals such as silver, gold, copper, or other conductive materials. In at least one embodiment, two or more different nanoparticle types can be employed to improve adhesion strength and conductivity, ensuring reliable interconnects between the microdevice and the substrate.

[0026] In at least one embodiment, polymer material covers the surface of the system substrate and microdevices can be bonded to the system substrate at a temperature higher than the glass transition temperature of the polymer. In at least one embodiment, microdevices include pads.

[0027] In at least one embodiment, after alignment, the system undergoes a controlled thermal or pressure process to decompose the polymer material under the microdevice pads This process ensures that the microdevices make direct electrical and mechanical contact with the system substrate, leaving behind only conductive nanoparticles or bumps to establish permanent connections.

[0028] In at least one embodiment, a solution can be used to remove the any remaining polymer and particles embedded in the polymer from a surface of the substrate. In at least one embodiment, the polymer materials can be deposited on top of conductive bumps. In at least one such embodiment, once polymer materials are decomposed, the microdevice may be bonded to the conductive pads on the system substrate.

[0029] Figure 1A is an illustration of a structure 100A. In at least one embodiment, structure 100A includes a microdevice 108 positioned above a system substrate 120. In at least one embodiment, structure 100A further comprises a decomposable material 124 and pads 122 within decomposable 5Attorney Docket No. - VR13P003PCT (VR13-000155PL01) material 124. In at least one embodiment, structure 100A is an embodiment of using a decomposable material for bonding. In at least one embodiment, decomposable material 124 is coated on system substrate 120.

[0030] Selective Surface Coating for Microdevice Bonding:

[0031] In at least one embodiment, decomposable material 124 is uniformly coated over an entire surface of system substrate 120 before microdevice bonding. In at least one such embodiment, decomposable material 124 surrounds pads 122. In at least one embodiment, pads 122 extend through decomposable material 124 and is in contact with system substrate 120. In at least one embodiment, pads 122 can be conductive or non-conductive. In at least one embodiment, microdevice 108 comprises one or more pads, such as pads 112 that are electrically coupled to microdevice 108. In at least one example, pads 112 comprise a conductive material.

[0032] In at least one embodiment, microdevice 108 comprises a pair of pads such as pads 112. In at least one embodiment, system substrate 120 comprises a plurality of pads 122. In at least one such embodiment, a layout of pads in microdevice 108 is designed to match pads 122 on system substrate 120.

[0033] In at least one embodiment, decomposable material 124 comprises one of: poly(methyl methacrylate) (PMMA), polystyrene (PS), poly propylene carbonate (PPC), or some photoresist that can decompose under certain conditions.

[0034] In at least one embodiment, pad 122 comprises one of: indium, gold, copper, tin, tungsten, carbon nanotube, silver, etc.

[0035] Figure 1B is an illustration of a structure 100B. In at least one embodiment, structure 100B is an illustration of structure 100A of Figure 1A, following a process to align pads 112 of microdevice 108 with top surface 122A of pads 122 within the decomposable material 124. In at least one embodiment, pads 122 may be bond pads. In at least one embodiment, microdevice 108 is positioned on the decomposable materials 124 and bonded using a temperature that exceeds a glass transition temperature of the decomposable materials 124.

[0036] In at least one embodiment, a plurality of microdevices 108 is aligned with the system substrate 120. In the illustrative embodiment, pads 112 of a single microdevice 108 are shown aligned and bonded with pads 122. In at least one embodiment, top surface 122A of each pad 122 can have a same or substantially the same cross-sectional shape and size as a lower surface 112A 6Attorney Docket No. - VR13P003PCT (VR13-000155PL01) of pad 112. In at least one embodiment, top surface 122A of each pad 122 can have a larger cross- sectional surface than a cross-sectional surface of lower surface 112A of pad 112.

[0037] In at least one embodiment, after alignment microdevice 108 is bonded to pads 122 within decomposable material 124. In at least one embodiment, a plurality of microdevices such as microdevice 108 are aligned and bonded with a plurality of pads 122. In at least one embodiment, a selected set of microdevices 108 are left on the system substrate 120 after bonding. In at least one embodiment, polymer material within decomposable material 124 covers a surface (not visible in Figure) of system substrate 120 and one or more microdevices 108 can be bonded to system substrate 120 at a temperature higher than the glass transition temperature of the polymer material within decomposable material 124.

[0038] Microdevice Bonding

[0039] Decomposable materials 124 are coated on the system substrate 120, covering or surrounding the bonding pads 122. The microdevices 108 are then placed on top of the decomposable material layer, ensuring proper alignment with the bonding pads. Figure 1C is an illustration of a structure 100C. In at least one embodiment, structure 100C is an illustration of structure 100B of Figure 1B, following a process of bonding and releasing decomposable material 124. In at least one embodiment, structure 100B is subjected to a process at pressures and temperatures that can decompose decomposable material 124, and couple microdevice 108 to system substrate 120, in at least one embodiment. In at least one example, microdevices 108 can be subjected to pressures in the range of 0.1-1000 N / mm2 and temperatures in the range of [20- 500 degrees Celsius to decompose decomposable material 124 and couple microdevice 108 to the system substrate 120, as shown.

[0040] In at least one embodiment, decomposable polymers can be mixed with conductive nanoparticles within pads 112. In at least one embodiment, pressure or temperature can be applied to decompose a polymer within decomposable material 124, leaving conductive particles between microdevice 108 and pads 122 on system substrate 120. In at least one embodiment, microdevices 108 can be bonded to system substrate 120 at a temperature that is the same or higher than a glass transition temperature of polymers within decomposable material 124. In at least one embodiment, the nanoparticles can be metals or other conductive materials. In at least one embodiment, two or more materials can assist in the mechanical bonding of a microdevice 108 to pads 122 in system substrate 120. 7Attorney Docket No. - VR13P003PCT (VR13-000155PL01)

[0041] In at least one embodiment, after transfer of microdevices, a high temperature and / or pressure process may be utilized to decompose the polymer materials within decomposable material 124 under pads 112. In at least one embodiment, pads 122 are conductive pads. In at least one further such embodiment, once polymer materials are decomposed, microdevice 108 may be bonded to conductive pads 122 on system substrate 120 allowing direct conduction between pads 112 (or microdevice 108) and pads 122 on system substrate 120.

[0042] In at least one embodiment, to ensure optimal performance and prevent contamination a solvent or etching solution can be used to remove any remaining polymer and can be applied to remove any residual polymer and nanoparticles that remain embedded on a surface 120A of the system substrate 120 after the decomposition process. Removal of residue can provide a clean and high-quality electrical interface between the microdevice 108 and system substrate 120.

[0043] Conductive Bump Integration for Direct Bonding

[0044] In at least one embodiment, conductive bumps may be implemented for direct bonding. Figure 1D is an illustration of a structure 100D. In at least one embodiment, decomposable material 124 is selectively deposited on top of conductive bumps 130 pre-formed on system substrate 120. In at least one embodiment, bumps may be fabricated from solder materials, metal nanoparticles, or other electrically conductive materials. In at least one embodiment, microdevice 108 is placed on conductive bumps 130 and bonded using a controlled temperature process.

[0045] Figure 1E is an illustration of a structure 100E. In at least one embodiment, upon decomposition of the decomposable material 124, microdevice 108 makes a direct electrical contact with the conductive bumps 130, providing for stable and reliable interconnects, as shown. Method of using bumps can provide enhanced electrical conductivity and improved mechanical stability, making it useful for high-performance microdevice applications, such as microLED displays, semiconductor integration, and micro-sensor arrays.

[0046] Hybrid Bonding with Multi-Layered Nanoparticle Interfaces

[0047] In at least one embodiment, conductive hybrid bonding with multi-layered nanoparticle interfaces may be utilized. Figure 1F is an illustration of a microdevice 108 positioned above a multi-layer structure 140, in at least one embodiment. In at least one embodiment, multi-layer structure 140 can be implemented to improve mechanical stability and enhance electrical performance of a bonded microdevice 108.

[0048] In at least one embodiment, multi-layer structure 140 comprises a first layer of 8Attorney Docket No. - VR13P003PCT (VR13-000155PL01) decomposable polymer 142 mixed with large conductive particles (e.g., silver or copper microflakes) applied to enhance mechanical anchoring, and a second layer of decomposable polymer 146 with smaller conductive nanoparticles (e.g., silver nanowires or carbon nanotubes) deposited on top on first layer of decomposable polymer 142 to improve electrical conductivity.

[0049] Figure 1G is an illustration of structure 100H. In at least one embodiment, structure 100F illustrates structure 100F in Figure 1F following a process to release multilayer structure 140. In at least one embodiment, following a release or decomposition of first layer of decomposable polymer 142 and second layer of decomposable polymer 146 in multi-layer structure 140, microdevice 108 is bonded with pads 122. Referring again to Figure 1F-1G, in at least one embodiment upon decomposition of first layer of decomposable polymer 142 and layer, the multi- layer structure 140 provides a robust conductive path, ensuring high electrical and mechanical performance. In at least one embodiment, utilizing a multi-layer structure 140 can be useful for applications requiring ultra-low resistance electrical interconnects, such as high-speed microprocessors and optoelectronic devices.

[0050] In at least one embodiment, structure 100G includes a conductive structure that comprises of two types of particles that are formed by combination after decomposition of decomposable polymer 142 and decomposable polymer 146. In at least one embodiment, the lower level includes large conductive nanoparticles 144 and an upper level includes smaller conductive nanoparticles 148 or above nano flakes. In at least one embodiment, after decomposition of decomposable polymer 146 and decomposable polymer 142, rectangle shaped layers are removed and nanoparticles and flakes can be meshed, as shown. In at least one embodiment, the stack of conductive nanoparticles 144 and conductive nanoparticles 148 may be meshed or fused together. In at least one embodiment, the stack of conductive nanoparticles 144 and conductive nanoparticles 148 may have an irregular boundary. Herein “irregular” may refer to jagged or not straight.

[0051] In at least one embodiment, a cross-sectional illustration through structure 100G in Figure 1G is illustrated in Figure 1H and 1I. In at least one embodiment, conductive nanoparticles 144 are large nanoparticles and conductive nanoparticles 148 can be nano flakes that are smaller in size compared to conductive nanoparticles 144.

[0052] Figures 1I is a cross section of structure 100I, taken along a line A-A in Figure 1G, in at least one embodiment. In at least one embodiment, conductive nanoparticles 144 are large 9Attorney Docket No. - VR13P003PCT (VR13-000155PL01) nanoparticles and conductive nanoparticles 148 can be nanowires that are smaller in size compared to conductive nanoparticles 144.

[0053] In at least one embodiment, while two different nanoparticles are illustrated the multilayer stack can include more than two different nanoparticles. In at least one embodiment, conductive nanoparticles 144 and conductive nanoparticles 148 include a same type of nanoparticle. In at least one embodiment, through layer engineering a same microdevice 108 can include two different nano particle combination above two different pads 122.

[0054] In at least one embodiment, laser or targeted heating methodology can be implemented to enable localized polymer decomposition. In at least one such embodiment, selective decomposition of decomposable material 124 (Figures 1B and 1E) can be achieved using localized heating methods such as laser-assisted decomposition or infrared heating. In at least one embodiment, laser-assisted decomposition or infrared heating can allow precise control over the bonding and decomposition processes, minimizing thermal exposure to sensitive microdevices.

[0055] In at least one embodiment, laser-based decomposition can also enable selective reworking of specific microdevices without affecting an entire system or microdevices, providing increased flexibility in manufacturing and repair processes.

[0056] Referring again to Figure 1A in at least one embodiment, a dielectric or an insulating pad can be implemented for enhanced alignment and positioning. Figure 1J is an illustration of a structure 100J that includes a dielectric 150 between decomposable material 124 and conductive pads 122, in at least one embodiment. In at least one embodiment, dielectric 150 may have a form of a spacer around pads 122. In at least one embodiment, the dielectric can include one of: silicon and one or more of oxygen, nitrogen or carbon. In at least one embodiment, insulating or dielectric layer is added between decomposable material 124 and conductive pads 122 to enhance microdevice positioning and prevent shorting during the bonding process. In at least one embodiment, the dielectric or an insulating layer can laterally surround pads 122 in a form of a spacer to ensure that only the intended conductive regions (such as an upper surface) are exposed after decomposition of decomposable material 124, enabling precise electrical connections to be formed. technique is particularly beneficial for high-density microdevice integration, where precise alignment and controlled interconnect formation are critical.

[0057] Referring again to Figures 1A and 1F conductive nanoparticles can enhance electrical connection between microdevices 108 and system substrate 120, reducing resistance and 10Attorney Docket No. - VR13P003PCT (VR13-000155PL01) improving reliability. In at least one embodiment, the approaches described in Figures 1A-1I also offer scalability and flexibility, where the different methods described are compatible with a range of materials and device architectures, including microLEDs, MEMS, and advanced semiconductor devices. In at least one embodiment, laser-assisted or localized thermal decomposition allows for precise control, minimizing damage to surrounding components, selective transfer and ability to rework processes such as re-transferring one or more microdevices with little impact to remaining microdevices that may have already been transferred with high fidelity.

[0058] In at least one embodiment, the methods described above can also enable high-density integration, such as enabling fine pitch microdevice bonding which may be useful for applications such as AR / VR micro-displays and compact sensor arrays.

[0059] In at least one embodiment, the methods described above may also be compatibility with multi-material integration processes. For embodiment, methods described above can support hybrid bonding of different microdevices, such as integrating microLEDs with silicon photonics or MEMS devices. In at least one embodiment, by incorporating one or more methods and processing techniques described above MicroSolid printing process using decomposable polymers or decomposable material 124 can be further optimized for next generation microdevice integration, providing enhanced performance, reliability, and manufacturing efficiency.

[0060] Advantages of the Expanded Process

[0061] Improved Electrical Performance: Conductive nanoparticles enhance the electrical connection between microdevices and system substrates, reducing resistance and improving reliability.

[0062] Scalability and Flexibility: The approach is compatible with a wide range of materials and device architectures, including microLEDs, MEMS, and advanced semiconductor devices.

[0063] Selective Transfer & Reworkability: Laser-assisted or localized thermal decomposition allows for precise control, minimizing damage to surrounding components.

[0064] High-Density Integration: Enables fine pitch microdevice bonding, essential for applications such as AR / VR microdisplays and compact sensor arrays.

[0065] Compatibility with Multi-Material Integration: The method supports hybrid bonding of different microdevices, such as integrating microLEDs with silicon photonics or MEMS devices.

[0066] By incorporating these advanced embodiments and processing techniques, the MicroSolid printing process using decomposable polymers can be further optimized for next generation 11Attorney Docket No. - VR13P003PCT (VR13-000155PL01) microdevice integration, providing enhanced performance, reliability, and manufacturing efficiency.

[0067] Figure 2 is a flow diagram of a method 200 to transfer a microdevice from a cartridge substrate to a system substrate, according to at least one embodiment. In at least one embodiment, method 200 begins at operation 210 by coating cartridge substrate with a decomposable layer. In at least one embodiment, decomposable layer is a release layer and helps to release microdevices to a system substrate. In at least one embodiment, the cartridge substrate can comprise glass, silicon, ceramic, or sapphire, and decomposable layer is a thermally decomposable polymer (TDP). In at least one embodiment, the TDP layer is patterned. In at least one embodiment, method 200 continues at operation 220 by positioning a diaphragm structure with a flat bonding area over the decomposable layer. In at least one embodiment, anchors may be utilized to secure the diaphragm structure to the cartridge substrate through designated openings. In at least one embodiment, method 200 continues at operation 230 by bonding the microdevice to the diaphragm structure using an adhesive layer. In at least one embodiment, method 200 continues at operation 240 by heating the cartridge substrate and decomposing the decomposable layer. In at least one embodiment, the cartridge substrate is subjected to a controlled heating process to decompose the TDP layer, freeing the diaphragm structure. In at least one embodiment, method 200 continues at operation 250 by bonding microdevice to a system substrate and transferring it by aligning the diaphragm structure with the system substrate. In at least one embodiment, method 200 concludes at operation 260 by removing the diaphragm structure.

[0068] Cartridge - Release Layer

[0069] In at least one embodiment, microdevice can be coupled with a diaphragm that is connected to a cartridge substrate. In at least one embodiment, a structure for the cartridge substrate includes a release layer and a diaphragm connected to the cartridge substrate at least at one point. In at least one embodiment, a microdevice is bonded to a flat surface of the diaphragm with an adhesive material. The release layer is removed before transferring microdevices from the cartridge substrate into the system substrate. The release layer can be a decomposable polymer, where a temperature activated process removes it from the cartridge substrate, in a manner similar to that described above.

[0070] In at least one embodiment, the decomposable polymer layer (with a temperature threshold) is deposited on a surface of a cartridge substrate. The decomposable polymer layer is patterned to 12Attorney Docket No. - VR13P003PCT (VR13-000155PL01) create a release layer. In at least one embodiment, the patterning can be done through masking and dry etching. The mask can be a photoresist or a coating such as metal or dielectric. In at least one embodiment, an anchor material is formed on top of the release layer and is connected to the cartridge substrate in at least one point. In at least one embodiment, anchor material may be mechanically coupled with the cartridge substrate. In at least one embodiment, other layers can be implemented between the anchor material and the cartridge substrate. In at least one embodiment, the anchor material can be metal, dielectric, or other polymers. In at least one embodiment, the anchor material can be formed using different deposition techniques such as plasma enhanced chemical vapor deposition (PECVD), electron beam, sputtering, coating, printing, or any other fabrication technique for thin film deposition. In at least one embodiment, the anchor material is patterned to have a flat surface for coupling to microdevices. In at least one embodiment, coupling can be performed through an adhesive layer.

[0071] In at least one embodiment, a microdevice is bonded to the adhesive layer and left on a flat surface of the anchor. In at least one embodiment, the adhesive layer can have a sacrificial layer that can be separated from the anchor or device. In at least one embodiment, the adhesive layer is part of the microdevice that bonds to the flat surface of the anchor.

[0072] Before transferring a microdevice from the cartridge substrate into a system substrate, the release structure is decomposed using temperature activated process. In at least one embodiment, microdevice is aligned with a location on a system substrate and bonded to the substrate. In at least one embodiment, bonding of the microdevice to the substrate can be stronger than the anchor force, so it removes the microdevice from the cartridge substrate. In at least one embodiment, the first adhesive layer can be removed from the microdevice by dry etching or wet etching. In at least one embodiment, the sacrificial layer is used, and the layer can be removed to separate the adhesive layer.

[0073] Figure 3 illustrates a cartridge structure 300. In at least one embodiment, cartridge structure 300 includes microdevice 308 coupled with a cartridge substrate 302 though a diaphragm structure 306. In at least one embodiment, the cartridge structure 300 further includes a thermally decomposable polymer (TDP) as a release layer 304 between cartridge substrate 302 and diaphragm structure 306.

[0074] In at least one embodiment, release layer 304 and diaphragm structure 306 are connected to the cartridge substrate at specific anchor points. In at least one embodiment, cartridge structure 13Attorney Docket No. - VR13P003PCT (VR13-000155PL01) 300 allows for precise control during the microdevice transfer process. In at least one embodiment, microdevice 308 is initially bonded to diaphragm structure 306, which features a flat surface designed for optimal adhesion. The bonding is facilitated using adhesive layer 310, and release layer 304 facilitates efficient and selective transfer of microdevices 308 onto the system substrate.

[0075] In at least one embodiment, release layer 304 is formed on top of cartridge substrate 302. In at least one embodiment, release layer 304 is formed using a thermally decomposable polymer (TDP) or other decomposable material, which can be removed through controlled heating. In at least one embodiment, decomposition of release layer 304 allows diaphragm structure 306 and the attached microdevice 308 to be detached and transferred effectively.

[0076] In at least one embodiment, release layer 304 has at least one opening to allow diaphragm structure 306 to contact cartridge substrate 302 or materials on the surface of cartridge substrate 302. In at least one embodiment, diaphragm structure 306 is formed on top of release layer 304. In at least one embodiment, diaphragm structure 306 comprises anchors 306B that connect to cartridge substrate 302 through the opening. In at least one embodiment, diaphragm structure 306 has an upper surface 306A. In at least one embodiment, upper surface 306A is flat and can support microdevice 308.

[0077] In at least one embodiment, microdevice 308 is bonded to upper surface 306A through an adhesive layer 310. In at least one embodiment, adhesive layer 310 can be formed on diaphragm structure 306. In at least one embodiment, after deposition, adhesive layer 310 can be patterned to cover upper surface 306A of diaphragm structure 306. In at least one embodiment, adhesive layer 310 can include one of: polyamide, photoresist material such as SU-8 (an epoxy-based negative photoresist), BCB (frequently used to create photosensitive polymers), or other types of polymers. In at least one embodiment, adhesive layer 310 can be formed on microdevice 308. In at least one embodiment, cartridge structure 300 can be inspected and undergoes measurements of performance characteristics of parameters useful for high yield transfer.

[0078] In at least one embodiment, cartridge substrate 302 can include one of: glass, silicon, ceramic, or sapphire. In at least one embodiment, cartridge substrate 302 is chosen to match one or more properties of a system substrate to assist a transfer process. In at least one embodiment, reducing thermal expansion mismatch between cartridge substrate 302 and the system substrate is useful. In at least one embodiment, one or more layers can be added to a top surface 302A of the 14Attorney Docket No. - VR13P003PCT (VR13-000155PL01) cartridge substrate 302 to enhance adhesion or other properties. In at least one embodiment, enhancing adhesion between diaphragm structure 306 and cartridge substrate 302 can be useful.

[0079] In at least one embodiment, cartridge substrate 302 can include different types of alignment marks on for various alignment processes. In at least one embodiment, there can be a first set of alignment marks for transferring microdevices 308 into cartridge substrate 302, a second set of alignment marks for processing cartridge structure 300 and a third set of alignment marks for transferring microdevices 308 from cartridge substrate 302 to the system substrate. In at least one embodiment, the alignment marks can also be shared for other processes.

[0080] In at least one embodiment, release layer 304 may be developed through the following sequence of operations. In at least one embodiment, initially, a layer of decomposable polymer can be deposited uniformly onto a surface of cartridge substrate 302. In at least one embodiment, the layer of decomposable polymer may be selected based on its decomposition temperature, adhesion properties, and compatibility with the microdevices and subsequent processing steps. In at least one embodiment, after deposition, the layer of decomposable polymer is patterned to form release layer 304. In at least one embodiment, patterning methods may include: masking and dry etching the layer of decomposable polymer using photoresists, metals, or dielectric materials as a mask. In at least one embodiment, laser-assisted ablation may be utilized for precise, localized removal of material. In at least one embodiment, micro-imprint lithography may be utilized for forming ultra- fine patterns. In at least one embodiment, an anchor material is formed over the release layer to secure diaphragm structure 306 at specific locations. In at least one embodiment, the anchor material could be composed of metals (such as aluminum, gold, or copper), dielectrics (like silicon nitride or oxide), or high-temperature polymers. In at least one embodiment, the anchor material is patterned to comprise a flat, smooth surface, optimizing it for bonding to adhesive layer 310. In at least one embodiment, anchors are connected at useful points to ensure diaphragm structure 306 remains mechanically intact during handling but can be detached when required. In at least one embodiment, anchor layer may also include a buffer layer to manage stress between diaphragm structure 306 and cartridge substrate 302, ensuring durability during thermal cycling.

[0081] In at least one embodiment, microdevice 308 is bonded to upper surface 306A through an adhesive layer 310. Adhesive layer 310 can be formed on diaphragm structure 306. In at least one embodiment, after deposition, adhesive layer 310 can be patterned to cover upper surface 306A of diaphragm structure 306. In at least one embodiment, adhesive layer 310 can include one of: 15Attorney Docket No. - VR13P003PCT (VR13-000155PL01) polyamide, SU8, BCB, or UV-curable adhesives, selected based on their mechanical and thermal properties. In at least one embodiment, adhesive layer 310 can be formed on microdevice 308. In at least one embodiment, adhesive layer 310 can incorporate a sacrificial layer designed to be selectively removed post-transfer. In at least one embodiment, the sacrificial layer allows for clean detachment of microdevice from diaphragm structure 306 post-bonding. In at least one embodiment, adhesive layer 310 is patterned to substantially match a shape of microdevice 308 and avoid overflow. In at least one embodiment, overflow can interfere with bonding accuracy.

[0082] Before initiating transfer, cartridge structure 300 undergoes inspection to ensure that all microdevices (such as microdevices 308) are correctly aligned and securely bonded to cartridge substrate 302. In at least one embodiment, prior to transfer, cartridge structure 300 undergoes detailed inspection using optical microscopy, X-ray imaging, or thermal profiling to ensure that all microdevices are correctly positioned and securely bonded.

[0083] In at least one embodiment, cartridge structure 300 can be inspected and undergo measurements for performance characteristics and other parameters useful for high yield transfer.

[0084] Figure 4 is an illustration of cartridge structure 400. In at least one embodiment, cartridge structure 400 is an illustration of cartridge structure 300 in Figure 3 following a process of decomposition of release layer 304. Referring collectively to Figures 3 and 4, in at least one embodiment, after measurements and inspection cartridge structure 300 undergoes a release process where temperature activation process is utilized to decompose release layer 304. In at least one embodiment, the release process may be gradual to avoid damaging cartridge structure 300. In at least one embodiment, release process undergoes controlled heating to decompose release layer 304. In at least one embodiment, heating in stages can prevent thermal stress and potential damage to the microdevice 308 or to diaphragm structure 306.

[0085] Localized Polymer Decomposition Using Laser or Targeted Heating

[0086] In at least one embodiment, alternative methods such as localized laser heating or infrared (IR) light exposure can also be employed for precise decomposition. In at least one embodiment, release layer 304 is decomposed, diaphragm structure 306 becomes free for transfer.

[0087] In at least one embodiment, cartridge structure 300 is then loaded into an alignment tool, ensuring that the diaphragm and attached microdevices 308 are correctly positioned relative to cartridge substrate 302. In at least one embodiment, after removal of release layer 304, cartridge structure 300 can go under another inspection as it is inserted into a tool that is designed to hold 16Attorney Docket No. - VR13P003PCT (VR13-000155PL01) and align it with a system substrate. In at least one embodiment, cartridge substrate 302 and system substrate are brought into contact and a selected set of microdevices 308 are bonded to the system substrate. In at least one embodiment, selected set of microdevices 308 are bonded to the system substrate using mechanical pressure, thermal energy, or a combination of both. In at least one embodiment, bond strength between the microdevices 308 and the system substrate is engineered to be greater than the anchor force, facilitating clean removal from the cartridge structure 300.

[0088] In at least one embodiment, post-transfer, diaphragm structure 306 may detach naturally, or the bonding adhesive may be selectively dissolved or etched away (using dry or wet etching techniques). In at least one embodiment, the transfer process includes breaking diaphragm structure 306 or separating microdevice 308 from adhesive layer 310 (bonding material). This process leaves the selected set of microdevices 308 on the system substrate.

[0089] In at least one embodiment, post-transfer, a secondary or tertiary inspection phase can be implemented to confirm quality of the bond between microdevice 308 and system substrate 302. In at least one embodiment, residual adhesive or decomposed materials are removed through plasma cleaning, wet etching, or ultrasonic cleaning to ensure a clean, high-quality final product.

[0090] In at least one embodiment, a multi-layer release structures may be implemented. In at least one embodiment, release layer 304 can be replaced by a multi-layer structure comprising multiple decomposable polymer layers. In at least one embodiment, each layer can have a unique decomposition temperature. This layered approach enables staged release of microdevices, allowing for selective transfer or multi-step integration processes. In at least one embodiment, a lower layer within the multi-layer structure can be designed to be released first under a first thermal condition, followed by an upper layer under a second thermal condition (such as at a different temperatures). In at least one embodiment, the lower layer may be in contact with cartridge substrate 302. Releasing multiple layers can be useful for integrating complex microdevice arrays or when multiple transfer stages are required.

[0091] In at least one embodiment, a laser-activated release layer may be implemented in cartridge structure 300. In at least one embodiment, release layer 304 can be sensitive to specific wavelengths of laser light, enabling selective and localized decomposition. In at least one embodiment, implementing a laser-activated release layer can be beneficial for transferring delicate microdevices or for scenarios requiring high precision, as it eliminates the risk of thermal damage to adjacent structures. 17Attorney Docket No. - VR13P003PCT (VR13-000155PL01)

[0092] In at least one embodiment, release layer 304 can be chemically decomposable. In another approach, release layer 304 may be designed to decompose upon exposure to specific chemical vapors or solutions. In at least one embodiment, implementing chemically decomposable release layer 304 can enable controlled release without a need for high temperatures. In at least one such embodiment, such a process can be suitable when microdevices 308 are temperature sensitive.

[0093] In at least one embodiment, cartridge structure 300 can implement a diaphragm structure 306 that is reusable. In at least one embodiment, diaphragm structure 306 may be engineered for reuse to improve process efficiency and offers sustainability. In at least one embodiment, after a release and transfer process, diaphragm structure 306 can be cleaned and reprocessed, allowing multiple cycles of microdevice bonding and transfer. In at least one embodiment, materials such as high-strength silicones, advanced polymers, or metals with protective coatings may be implemented for this reusable approach.

[0094] In at least one embodiment, gradient adhesive bonding may be implemented. In at least one embodiment, adhesive layer 310 has a gradient composition and a bonding strength that varies across a surface. In at least one embodiment, the variation can be at a surface that is in contact with diaphragm structure 306. In at least one embodiment, an adhesive layer 310 with a gradient composition can be useful in that microdevices at some locations can be more securely bonded, while others can be easily released. In at least one embodiment, this method allows for precise control of selective transfer and may be suitable for high-density or heterogeneous integration processes.

[0095] In at least one embodiment, release layer 304 can be a self-healing polymer layer. After decomposition and transfer, the remaining structure can be repaired in situ, extending lifespan of cartridge structure 300 and reducing material waste.

[0096] In at least one embodiment microdevices are coupled with a cartridge substrate using a material with a low glass transition temperature. The glass–liquid transition, or glass transition, is a gradual and reversible transition process in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle glassy state into a viscous or rubbery state as the temperature is increased. An amorphous solid that exhibits a glass transition is called a glass. In at least one embodiment, glass transition temperature can range from 140°C to 370°C according to the grades, curing process and the moisture content of the amorphous or semicrystalline material. The glass transition temperature TG of a material characterizes the range 18Attorney Docket No. - VR13P003PCT (VR13-000155PL01) of temperatures over which glass transition occurs. In at least one embodiment, from an experimental perspective temperature relaxation time can be approximately 100s.

[0097] In at least one embodiment, cartridge substrate may include one of: glass, silicon, ceramic, or sapphire, and provides a stable base for subsequent layers.

[0098] Figure 5 illustrates an illustration of structure 500. In at least one embodiment, structure 500 includes a microdevice 508 integrated on a cartridge substrate 502 using a low glass transition temperature (LGT) material 504, implemented for cartridge development. In at least one embodiment, LGT material 504, can be formed on top of a cartridge substrate 502.

[0099] In at least one embodiment microdevice 508 is coupled with cartridge substrate 502 using a material with a low glass transition temperature. In at least one embodiment, LGT material 504 can be utilized to facilitate precise bonding and transfer of microdevice 508 from cartridge substrate 502 to a system substrate. In at least one embodiment, LGT material 504 comprises controllable adhesion properties, enabling efficient microdevice handling, bonding, and release under specific thermal conditions. In at least one embodiment, LGT material 504 provides flexibility in processing, especially when temperature-sensitive microdevices are involved. In at least one embodiment, LGT material 504 can be thermally decomposable material and cleaned after the transfer. In at least one embodiment, LGT material 504 can be deposited uniformly using a material with a low glass transition temperature TG. In at least one embodiment, a low glass transition temperature TG can facilitate controlled softening and decomposition during the bonding process. In at least one embodiment, there can be other material layers between the cartridge substrate 502 and the LGT material 504.

[0100] In at least one embodiment, a bonding pad 510 can be formed on top of the LGT material 504 and microdevices 508 are bonded to the bonding pad 510. In at least one embodiment, bonding pad 510 allows selective integration of one or more microdevices such as microdevice 508 from an array of microdevices into a cartridge substrate 502. In at least one embodiment, the bonding pad may be inserted between the LGT material 504 and microdevice 508 to facilitate selective bonding and efficient transfer.

[0101] In at least one embodiment, a buffer or adhesion enhancement layer may be inserted between cartridge substrate 502 and the LGT material 504 to optimize adhesion and manage stress. This configuration allows for the selective release of microdevices upon controlled heating, ensuring that only the intended devices are transferred while maintaining the integrity of the 19Attorney Docket No. - VR13P003PCT (VR13-000155PL01) remaining structure.

[0102] In at least one embodiment, cartridge substrate 502 comprises one of: glass, silicon, ceramic, or sapphire, providing a stable base for subsequent layers. In at least one embodiment, the pad can be the same as the LGT layer. In at least one embodiment, microdevice can be precisely positioned and bonded to the bonding pad or LGT layer.

[0103] To transfer at least a single microdevice 508 from cartridge substrate 502 to a system substrate, structure 500 is aligned with a system substrate. In at least one embodiment, a selective transfer process may be implemented. In at least one embodiment, during transfer, thermal energy is applied to weaken adhesion between LGT material 504 and adjacent materials. In at least one embodiment, in structure 500, LGT material 504 is between cartridge substrate 502 and bonding pad 510. In at least one such embodiment, thermal energy is applied to weaken adhesion between LGT material 504 and bonding pad 510 as well as between LGT material 504 and cartridge substrate 502. In at least one embodiment, thermal energy is applied to enable a clean and efficient release of microdevice 508.

[0104] Figure 6 illustrates a structure 500. In at least one embodiment, structure 500 includes a microdevice 508 integrated into a cartridge substrate 502 cartridge development.

[0105] In at least one embodiment, bonding pad 510 may be absent between microdevice 508 and LGT material 504. In one such embodiment, microdevice 508 can be directly bonded to LGT material 504. In at least one embodiment, LGT material 504 can be patterned or formed as a continuous layer. This structure allows all the microdevices from an array of microdevices to become integrated into a system substrate.

[0106] In at least one embodiment, bonding pad 510 is on top of cartridge substrate 502. In at least one such embodiment, bonding pad 510 is between LGT material 504 and cartridge substrate 502. In at least one embodiment, other layers such as buffer layer, or an adhesion enhancement layer can be included between cartridge substrate 502 and bonding pad 510. In at least one such embodiment, additional layers can be inserted below bonding pad 510 on surface 502A of cartridge substrate 502. In at least one embodiment, bonding pad 510 has a height that is selected to reduce or avoid interference during microdevice bonding. In at least one embodiment, a sufficient height of bonding pad 510 can help eliminate interference between cartridge and other devices during transfer from the cartridge substrate 502 to a system substrate.

[0107] In at least one embodiment, a structured pad configuration may be implemented to enhance 20Attorney Docket No. - VR13P003PCT (VR13-000155PL01) the transfer process. In at least one embodiment, bonding pad 510 may be formed by depositing a pad layer over cartridge substrate 502. In at least one embodiment, the pad layer may be patterned to form bonding pad 510. In at least one embodiment, pad layer is not patterned until after LGT material 504 is deposited. In at least one embodiment, when pad layer is patterned and formed into bonding pad 510, it can be used for alignment, electrical conduction, as well as for mechanical support. In at least one embodiment, LGT material 504 is applied or deposited over bonding pad 510. In at least one embodiment, LGT material 504 is in contact with bonding pad 510. In at least one embodiment, a selective patterning is performed to match a shape of bonding pad 510 as shown. In at least one embodiment, microdevice 508 is bonded with bonding pad 510 that is coated with LGT material 504. In at least one embodiment, height of bonding pad 510 can be tuned to reduce interference during bonding and transfer operations.

[0108] In at least one embodiment, bonding pad 510 can be composed of conductive or adhesive materials, such as metals or specialized polymers, ensuring a strong initial bond and facilitating electrical connectivity if required. In at least one embodiment, there can be other layers between bonding pad 510 and cartridge substrate 502, between bonding pad 510 and the LGT material 504, or between the LGT material 504 and microdevice 508. In at least one embodiment, one or more additional layers include buffer or adhesion enhancement layer. In at least one embodiment, adhesion enhancement or buffer layer can be implemented before or after formation of bonding pad 510 or after formation of bonding pad 510 but before formation of LGT material 504.

[0109] To transfer at least a single microdevice 508 from cartridge substrate 502 to a system substrate, structure 600 is aligned with a system substrate. In at least one embodiment, a selective transfer process may be implemented. In at least one embodiment, during transfer thermal energy is applied to weaken adhesion between LGT material 504 and adjacent materials. In at least one embodiment, in structure 600, LGT material 504 is between microdevice 508 and bonding pad 510. In at least one such embodiment, thermal energy is applied to weaken adhesion between LGT material 504 and bonding pad 510 as well as between LGT material 504 and microdevice 508. In both embodiments, thermal energy is applied to enable a clean and efficient release of microdevice 508. A method to utilize is particularly useful for mass transfer processes where multiple microdevices are bonded and transferred simultaneously.

[0110] As a variation to structure 600, in at least one embodiment, microdevice 508 is bonded to LGT material 504 without intermediary bonding pad 510. This streamlined approach can simplify 21Attorney Docket No. - VR13P003PCT (VR13-000155PL01) the fabrication manufacturing process and can enhances bonding efficiency. In at least one embodiment, LGT material 504 uniformly deposited and can cover surface of cartridge substrate 502. In at least one embodiment, LGT material 504 can form a continuous layer. In at least one embodiment, LGT material 504 can be patterned according to device specifications. In at least one embodiment, microdevice 508 is bonded directly to LGT material 504 using a controlled temperature process, ensuring sufficient adhesion while allowing for easy release upon heating. In at least one embodiment, during transfer thermal energy is applied to weaken adhesion between LGT material 504 and adjacent materials to enable a clean and efficient microdevice release.

[0111] The selected microdevice 508 is bonded to the system substrate with a temperature that reduces the adhesion force of the LGT.

[0112] In at least one embodiment, structure 500 (Figure 5) or structure 600 (Figure 6) can be implemented with a multi-layer structure comprising two or more LGT materials.

[0113] Figure 7 illustrates a cross section of a structure 700 including a multi-layer structure 702 comprising two or more LGT materials, in at least one embodiment. In at least one embodiment, the multi-layer structure 702 can facilitate selective transfer capabilities. In at least one embodiment, multi-layer structure 702 can include a primary LGT layer 702A and a secondary LGT layer 702B on primary LGT layer 702A. In at least one embodiment, primary LGT layer 702A and secondary LGT layer 702B include materials that are same or substantially the same as material of LGT material 504 (Figure 5), but primary LGT layer 702A and secondary LGT layer 702B are different from each other. In at least one such embodiment, differences may stem from material differences or characteristic differences as discussed below. In at least one embodiment, primary LGT layer 702A provides initial adhesion and structural support. In at least one embodiment, secondary LGT layer 702B may be formulated with a different decomposition temperature compared to a decomposition temperature of primary LGT layer 702A. In at least one embodiment, differences in decomposition temperature are designed to facilitate staged release of microdevices. A staged release can enable selective transfer, where certain microdevices are released earlier than others based on controllable heating profiles. In at least one embodiment, additional one or more intermediate layers such as an adhesion enhancement layer can be added to fine-tune adhesion strength, thermal management, or mechanical stability. In at least one embodiment, a multi-layer structure 702 can support multi-stage transfer processes and may be suitable for integrating complex arrays of heterogeneous microdevices. 22Attorney Docket No. - VR13P003PCT (VR13-000155PL01)

[0114] Figure 8 illustrates a cross section of a structure 800 including a multi-layer structure 702 comprising two or more LGT materials, in at least one embodiment. In at least one embodiment, structure 800 is a variation of structure 600 (Figure 6), where a single layer LGT material 504 is replaced by a multi-layer structure 702. In at least one embodiment, the multi-layer structure 702 can facilitate selective transfer capabilities. In at least one embodiment, multi-layer structure 702 include primary LGT layer 702A and secondary LGT layer 702B on primary LGT layer 702A. In at least one embodiment, multi-layer structure 702 is between microdevice 508 and bonding pad 510.

[0115] Referring again to Figures 5-6, in at least one embodiment, to facilitate transfer of microdevices from LGT material 504, different thermal strategies can be implemented. In at least one embodiment, cartridge substrate 502 is aligned with a system substrate and heat is applied to reduce adhesion force of LGT material 504. In at least one embodiment, decomposition temperature is controlled to approach but not exceed a glass transition temperature (TG) of LGT material 504. In at least one embodiment, a controlled ramping on temperature can provide a smooth and efficient release without damaging sensitive microdevices. In at least one embodiment, after transfer, remaining residual LGT material 504 can be cleaned or etched from the microdevice and substrate to provide a clean bonding interface.

[0116] In at least one embodiment, LGT material 504 is formulated to be thermally decomposable during the transfer process, the temperature is increased beyond a decomposition threshold, causing LGT material 504 layer to vaporize or degrade. In at least one embodiment, vaporization or degradation can facilitate a clean separation of microdevice 508 from cartridge substrate 502, leaving little to no residue. In at least one embodiment, post-transfer a cleaning process, including plasma treatment and / or solvent cleaning can be employed to remove remaining contaminants.

[0117] In at least one embodiment, a laser or light induced transfer process may be implemented to remove microdevice 508 from cartridge substrate 502. In at least one embodiment, a laser or a light-induced heating process can be implemented to locally increase temperature of LGT material 504 for selected microdevices. In at least one embodiment, by applying localized heating to specific areas of cartridge substrate 502 can offer precision in removal of microdevice 508. In at least one embodiment, precision removal can be useful for selective, localized transfer of microdevices without affecting neighboring microdevices. In at least one embodiment, wavelength and intensity of the laser can be tuned based on a specific decomposition characteristic of LGT 23Attorney Docket No. - VR13P003PCT (VR13-000155PL01) material 504.

[0118] In at least one embodiment, a reusable substrate cartridge design can be implemented to enhance sustainability and reduce manufacturing costs. In at least one embodiment, after transfer of microdevice 508, residual LGT material 504 can be cleaned or thermally treated to remove decomposed residues. This method may be applied in instances where LGT material 504 is directly on cartridge substrate 502. In at least one embodiment, LGT material 504 is reapplied or deposited, and cartridge substrate 502 can be reprocessed for subsequent bonding cycles. In at least one embodiment, reuse of cartridge substrate 502 can be supported by use of durable base materials, such as sapphire, reinforced glass, or coated ceramics, which can withstand multiple thermal cycles without degradation.

[0119] In at least one embodiment, a hybrid LGT material 504 may be implemented. In at least one embodiment, such hybrid LGT material 504 can have self-healing properties. In at least one embodiment, hybrid LGT material 504 can extend cartridge lifespan and enhance process efficiency. In at least one embodiment, after decomposition and transfer, hybrid LGT material 504 including a self-healing polymer can be activated via controlled heating or ultraviolet exposure, allowing the layer of hybrid LGT material 504 to reform and smoothen for subsequent microdevice bonding. In at least one embodiment, implementing a hybrid LGT material 504 can reduce material waste and reduce a need for continuous reapplication of LGT material 504, streamlining production processes.

[0120] Post transfer cleaning and examination of system substrate for quality is important for fabrication process. In at least one embodiment, after transfer of microdevice 508, system substrate can be cleaned and inspected to ensure product quality. In at least one embodiment, residue cleaning may be performed by one of: a plasma treatment, solvent immersion, or chemical etching may be used to remove residual LGT material 504 from the transferred microdevices and system substrate. In at least one embodiment, visual and structural inspection may be performed for quality assurance. In at least one embodiment, visual and structural inspection can include one of: optical microscopy, scanning electron microscopy (SEM), or x-ray analysis to check for clean bonding interfaced for structural integrity. In at least one embodiment, testing may be performed for adhesion strength. In at least one embodiment, adhesion strength may be measured by performing mechanical tests, such as peel or shear tests to confirm the integrity of the transferred microdevices. 24Attorney Docket No. - VR13P003PCT (VR13-000155PL01)

[0121] In some instances, well-known methods and devices are shown in block diagram form, rather than in detail, to avoid obscuring at least one embodiment. Reference throughout this specification to “an embodiment,” “one embodiment,” “in at least one embodiment,” or “some embodiments” means that a particular feature, structure, function, or characteristic described in connection with embodiment is included in at least one embodiment. Thus, appearances of phrase “in an embodiment,” “in at least one embodiment,” “in one embodiment,” or “some embodiments” in various places throughout this specification are not necessarily referring to same embodiment of disclosure. Furthermore, particular features, structures, functions, or characteristics may be combined in any suitable manner in one or more embodiments. For example, a first embodiment may be combined with a second embodiment anywhere particular features, structures, functions, or characteristics associated with two embodiments are not mutually exclusive.

[0122] As used in herein, singular forms “a,” “an,” and “the” are intended to include plural forms as well, unless context clearly indicates otherwise. It will also be understood that term “and / or” as used herein refers to and encompasses all possible combinations of one or more of associated listed items.

[0123] Here, “coupled” and “connected,” along with their derivatives, may be used herein to describe functional or structural relationships between components. These terms are not intended as synonyms for each other. Rather, in particular examples, “connected” may be used to indicate that two or more elements are in direct physical, optical, or electrical contact with each other. “Coupled” may be used to indicated that two or more elements are in either direct or indirect (with other intervening elements between them) physical, electrical, or in magnetic contact with each other, and / or that two or more elements co-operate or interact with each other (e.g., as in a cause an effect relationship).

[0124] Here, “over,” “under,” “between,” and “on” as used herein refer to a relative position of one component or material with respect to other components or materials where such physical relationships are noteworthy. For example, in context of materials, one material or material disposed over or under another may be directly in contact or may have one or more intervening materials. Moreover, one material disposed between two materials may be directly in contact with two layers or may have one or more intervening layers. In contrast, a first material “on” a second material is in direct contact with that second material / material. Similar distinctions are to be made in context of component assemblies. As used throughout this description, and in claims, a list of 25Attorney Docket No. - VR13P003PCT (VR13-000155PL01) items joined by term “at least one of” or “one or more of” can mean any combination of listed terms.

[0125] Here, “adjacent” generally refers to a position of a thing being next to (e.g., immediately next to or close to with one or more things between them) or adjoining another thing (e.g., abutting it).

[0126] Here, “signal” may refer to current signal, voltage signal, magnetic signal, or data / clock signal.

[0127] Here, “device” may generally refer to an apparatus according to context of usage of that term. For example, a device may refer to a stack of layers or structures, a single structure or layer, a connection of various structures having active and / or passive elements. Generally, a device is a three-dimensional structure with a plane along x-y direction and a height along z direction of an x-y-z Cartesian coordinate system. In at least one example, plane of device may also be plane of an apparatus which comprises device.

[0128] Unless otherwise specified in explicit context of their use, terms “substantially equal,” “about equal,” and “approximately equal” mean that there is no more than incidental variation between two things so described. Such variation is typically no more than + / -10% of a predetermined target value.

[0129] Here, “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and similar terms are used for descriptive purposes and not necessarily for describing permanent relative positions. For example, terms “over,” “under,” “front side,” “back side,” “top,” “bottom,” “over,” “under,” and “on” as used herein refer to a relative position of one component, structure, or material with respect to other referenced components, structures, or materials within a device, where such physical relationships are noteworthy. These terms are employed herein for descriptive purposes only and predominantly within the context of a device z-axis and therefore may be relative to an orientation of a device. Hence, a first material “over” a second material in context of a figure provided herein may also be “under” second material if the device is oriented upside-down relative to context of figure provided. Similar distinctions are to be made in the context of component assemblies.

[0130] Here, “between” may be employed in context of z-axis, x-axis, or y-axis of a device. A material that is between two other materials may be in contact with one or both of those materials. In another example, a material that is between two or other materials may be separated from both 26Attorney Docket No. - VR13P003PCT (VR13-000155PL01) of other two materials by one or more intervening materials. A material “between” two other materials may therefore be in contact with either of other two materials. In another example, a material “between” two other materials may be coupled to other two materials through an intervening material. A device that is between two other devices may be directly connected to one or both of those devices. In another example, a device that is between two other devices may be separated from both of the other two devices by one or more intervening devices.

[0131] While examples and applications of the present disclosure have been illustrated and described, it is to be understood that the disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the spirit and scope of the disclosure as defined in the appended claims. 27

Claims

Attorney Docket No. - VR13P003PCT (VR13-000155PL01) CLAIMS What is claimed is:

1. A method of integrating a microdevice into a system substrate using a decomposable polymer in a MicroSolid printing process, the method comprising: metalizing a substrate by mixing metal powders in the decomposable polymer under light or temperature; patterning using a printing process; and decomposing the decomposable polymer to sinter the metal powders.

2. The method of claim 1, wherein a plurality of metals is used to achieve sintering and a high conductivity at a first process temperature.

3. The method of claim 2, wherein the plurality of metals comprises powders of silver and indium.

4. The method of claim 1, wherein the decomposable polymer is mixed with conductive nanoparticles.

5. The method of claim 4, wherein materials are formed in a bump format on a receiver substrate and the microdevice is bonded at a second temperature that is at least equal to a first glass transition temperature of the decomposable polymer.

6. The method of claim 5, wherein after transferring the microdevice, applying a pressure or a third temperature to decompose the decomposable polymer, leaving the conductive nanoparticles between the microdevice and conductive pads in the system substrate.

7. The method of claim 6, wherein the conductive nanoparticles are metals or other conductive materials.

8. The method of claim 6, wherein two or more materials assist in mechanical bonding of the 28Attorney Docket No. - VR13P003PCT (VR13-000155PL01) microdevice to the conductive pads.

9. The method of claim 4, wherein the decomposable polymer covers a surface of the system substrate and wherein the microdevice is bonded to the system substrate at a fourth temperature higher than a second glass transition temperature of the decomposable polymer.

10. The method of claim 9, wherein after bonding, a second temperature or pressure is used to decompose the decomposable polymer under microdevice pads and create conduction between the microdevice pads and contacts on the system substrate.

11. The method of claim 10, a solution is used to remove remaining decomposable polymer and particles embedded in the decomposable polymer from the surface of the system substrate.

12. The method of claim 4, wherein the decomposable polymer is deposited on top of conductive bumps and wherein after the decomposable polymer is decomposed, the microdevice is bonded to conductive pads.

13. A method of integrating a microdevice into a system substrate, the method comprising: coating cartridge substrate with a layer of decomposable polymer; positioning a diaphragm structure over the layer of the decomposable polymer; bonding the microdevice to the diaphragm structure using an adhesive layer; heating the cartridge substrate and decomposing the layer of the decomposable polymer; bonding the microdevice to the system substrate and transferring the microdevice by aligning the diaphragm structure with the system substrate; and removing the diaphragm structure.

14. The method of claim 13, wherein the layer of the decomposable polymer and the diaphragm structure are connected to the cartridge substrate at anchor points.

15. The method of claim 13, wherein the diaphragm structure comprises a flat bonding area, 29Attorney Docket No. - VR13P003PCT (VR13-000155PL01) and wherein the microdevice is coupled to the flat bonding area of the diaphragm structure.

16. The method of claim 13, wherein the diaphragm structure comprises anchors that connect to the cartridge substrate through an opening in the diaphragm structure.

17. The method of claim 13, wherein adhesive comprises one of: polyamide, or photoresist material which includes one of SU-8 or benzo cyclobutene.

18. The method of claim 13, wherein the decomposable polymer comprises one of: poly(methyl methacrylate) (PMMA), polystyrene (PS), poly propylene carbonate (PPC), or photoresist.

19. The method of claim 13, wherein the cartridge substrate comprises one of: glass, silicon, ceramic, or sapphire.

20. The method of claim 13, wherein prior to positioning the diaphragm structure the method further comprises patterning the decomposable polymer to form a release layer.

21. The method of claim 13, wherein decomposing the layer of the decomposable polymer further comprises using localized laser-assisted ablation or infrared (IR) light exposure for precise decomposition.

22. The method of claim 13, an anchor material is formed over the layer of the decomposable polymer to secure the diaphragm structure, wherein the anchor material comprises one of a conductor, a dielectric, or a polymer.

23. A method of integrating a microdevice into a system substrate using a decomposable polymer, the method comprising: forming a bond pad on the system substrate; coating system substrate with a decomposable layer, wherein the decomposable polymer surrounds the bond pad; aligning the microdevice comprising a pad above the bond pad; 30Attorney Docket No. - VR13P003PCT (VR13-000155PL01) bonding the pad with the bond pad; and decomposing the decomposable layer and fusing the bond pad with the pad by applying temperature and pressure.

24. The method of claim 23, wherein the pad comprises conductive material.

25. The method of claim 23, wherein the bond pad comprises one of: indium, gold, copper, tin, tungsten, carbon nanotube, or silver.

26. The method of claim 23, wherein after formation of the bond pad, the method further comprises forming a dielectric on at least sidewalls of the bond pad.

27. The method of claim 26, wherein the dielectric comprises silicon and one of: oxygen, nitrogen, or carbon.

28. The method of claim 27, wherein bonding the microdevice comprising bringing into contact the pad with the dielectric.

29. The method of claim 23, wherein bonding the pad with the bond pad comprises bonding at a first temperature higher than a glass transition temperature of the decomposable polymer.

30. A method of integrating a microdevice into a system substrate, the method comprising: forming a bond pad on the system substrate; coating system substrate with a multi-layer stack of decomposable polymers, wherein the multi-layer stack of decomposable polymers surrounds the bond pad; aligning the microdevice with a pad above the bond pad; bonding the pad with the bond pad; and decomposing the multi-layer stack of decomposable polymers and fusing the bond pad with the pad by applying temperature and pressure.

31. The method of claim 30, wherein the multi-layer stack of decomposable polymers comprises a first layer of first decomposable polymer mixed with first conductive 31Attorney Docket No. - VR13P003PCT (VR13-000155PL01) nanoparticles on a second layer of second decomposable polymer comprising second conductive nanoparticles.

32. The method of claim 31, wherein the first conductive nanoparticles comprise silver or copper and wherein the second conductive nanoparticles comprise silver nanowires or carbon nanotubes.

33. The method of claim 31, wherein bonding the pad with the bond pad comprises bonding at a first temperature higher than a glass transition temperature of the first decomposable polymer and the second decomposable polymer.

34. A method of integrating a microdevice into a system substrate, the method comprising: forming a bump on the system substrate; coating system substrate with a decomposable polymer, wherein the decomposable polymer surrounds the bump; aligning the microdevice with a pad above the bump; bonding the pad with the bump; and decomposing the decomposable polymer and fusing the bump with the pad by applying temperature and pressure. 32

Images