Integration and bonding of micro-devices into system substrate
This disclosure is related to integrating optoelectronics microdevices into a system substrate for efficient and durable electrical bonding between two substrates at low temperature. 2D nanostructures and 3D scaffolds may create interlocking structures for improved bonding properties. Addition of nanoparticles into the structure creates high surface area for better conduction. Application of curing agents before or after alignment of micro devices and receiving substrates further assists with formation of strong bonds.
1 . A method of electrically bonding microdevices, the method comprising:
providing at least one bonding pad on a receiver substrate, and at least one optoelectronic microdevice on a donor substrate;
texturing at least a portion of a surface of the at least one bonding pad, at least a portion of a surface of the at least one optoelectronic microdevice, or both, to increase a respective surface area, the texturing performed via ion milling, laser ablation, reactive ion etching, dry etching, wet etching, or any combination thereof; and
electrically bonding at least the portion of the surface of the at least one bonding pad to at least the portion of the surface of the at least one optoelectronic microdevice.
2 . The method of claim 1 , further comprising, after the texturing, covering one or both of the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice with a conductive layer.
3 . The method of claim 1 , wherein the texturing includes forming a plurality of nanostructures on one or both of the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice.
4 . The method of claim 3 , wherein the plurality of nanostructures include nonconductive nanostructures, conductive nanostructures, or both.
5 . The method of claim 3 , wherein the plurality of nanostructures are nanotextured, nanoporous, metal nanopores, or any combination thereof.
6 . The method of claim 3 , wherein the plurality of nanostructures are in a form of nanoparticles, nanopillars, nanowires, nanoneedles, nanocones, silica coated nanoparticles, or any combination thereof.
7 . The method of claim 3 , wherein the plurality of nanostructures are separated by a transparent dielectric material that includes polyamide, SU8, PMMA, BCB thin film layers, or any combination thereof.
8 . The method of claim 3 , wherein the plurality of nanostructures are formed in a random order or an aligned order on one or both of the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice.
9 . The method of claim 8 , wherein the nanostructures in the random order nanostructures are formed with a self-mask etching or through combining silica or polystyrene nanosphere lithography and etching.
10 . The method of claim 8 , wherein the nanostructures in the aligned order are formed with a controlled lithographic process or nanosphere masks.
11 . The method of claim 3 , further comprising depositing at least one bonding agent on one or both of the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice.
12 . The method of claim 11 , wherein the at least one bonding agent fills a space between the plurality of nanostructures.
13 . The method of claim 11 , wherein the bonding agent comprises at least a material that includes indium, tin, silver, or any combination thereof.
14 . The method of claim 11 , wherein the at least one bonding agent is deposited on both the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice, and wherein the electrically bonding includes applying current at a low temperature to form eutectic bonding between the bonding agents.
15 . The method of claim 1 , further comprising applying a curing agent on one or both of the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice to enhance the bonding between the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice.
16 . The method of claim 15 , wherein the curing agent includes polyamide, SUS, PMMA, BCB thin film layers, epoxies, UV curable adhesives, or any combination thereof.
17 . The method of claim 16 , wherein the curing agent is cured via of one of: a current, a light, a thermal, a mechanical force or a chemical reaction.
18 . The method of claim 1 , further comprising forming a template on a space between the surfaces to enhance the bonding between the portion of the surface of the at least one bonding pad and the portion of the surface of the at least one optoelectronic microdevice.
19 . The method of claim 18 , wherein the template includes Block-Copolymers (BCPs) and aluminum anodic oxide (AAO), a patterned etch mask, a silica nanosphere a polystyrene bead, or any combination thereof.
20 . The method of claim 18 , further comprising forming a plurality of nanotextured structures by depositing a bonding agent onto the template using growth mechanism or electrochemical plating.
21 . The method of claim 20 , further comprising removing the template via an etching process.