Self assembly of microcomponents on patterned substrate using capillary force

In recent times there are many publications on guided self-assembly to generate heterogeneous and/or functional integrations, particularly in microelectronics area. A promising approach attempted in this investigation is self-assembly using capillary forces. In this approach, microcomponents flow over a target substrate patterned with binding sites, and part-substrate attachment and alignment occurs spontaneously due to free energy minimization of the binding site (e.g., a liquid column of lubricant). Silicon die chiplets (1 /spl times/ 1 mm) are diced from gold sputtered and patterned 8" wafer. Correspondingly matching gold pattern arrays (10 /spl times/ 10) made on 8" silicon wafer. Each gold pattern array is about 3/spl times/3 cm dimensions. Prior to assembly, both dies and gold patterned substrates were treated with thiol based self assembled monolayer (SAM). After SAM treatments on the substrate, lubricant is immobilized. Later the lubricant immobilized substrate wafer placed in a water bath. SAM treated dies allowed to pass on the substrate. The hydrophobic SAM treated face of the die attracted by hydrophobic lubricant sites on the substrate and assembled spontaneously aided by capillary force. Minimization of the free energy of the lubricant-water interface provided the driving force for the assembly. The X-ray diffraction characterizations of gold depositions are also performed to select gold deposition technique.