Wafer-level packaging based on uniquely orienting self-assembly (the DUO-SPASS processes)

Abstract

Abstract-A wafer-level packaging strategy for micro device chips based on uniquely orienting self-assembly is presented with the following steps: 1) bulk parts are uniquely face-oriented and spread in a single layer; 2) parts are palletized onto an alignment template having an array of receptor sites; 3) parts are anchored one-to-one to the receptor sites; 4) each anchored part is fixed to a unique in-plane orientation. We demonstrate all of these steps with two different self-organizing parallel assembly (SPASS) processes: a semidry uniquely orienting process (semi-DUO-SPASS) and a dry uniquely orienting (DUO-SPASS) process. The semidry process exploits: 1) an agitated air/water interface to uniquely face-orient bulk parts having a single hydrophobic face; 2) a hydrophobic carrier wafer to palletize the parts in an air environment; 3) orbital shaking to drive the parts until they are anchored to receptor sites; 4) gravity to uniquely align the parts. Experiments show that 2-mm square silicon parts are correctly registered on a 4-in alignment template having 164 receptor sites with a defect rate of 1% after 3 min orbital shaking. The dry process utilizes: 1) asymmetry in dynamic stability to uniquely face-orient bulk parts having protruding features on one face; 2) orbital shaking to drive the parts until they are first anchored to receptor sites and then fixed in well-defined in-plane orientations by two-stage shape recognition. In our experiments, 1-mm square silicon parts are assembled with a defect rate of 2% in 10 min on each of two 4-in alignment templates having, respectively, 397 and 720 receptor sites.[1490]Index Terms-Self-organizing parallel assembly (SPASS) process, two-stage shape recognition, uniquely orienting self-assembly, wafer-level packaging.

Programmable self-assembly for microsystem integration

“…Our laboratory previously demonstrated the use of mechanical agitation to distribute components in an air environment, and the use of shape matching to capture and align components [26]. In [27], our laboratory similarly uses shape matching to capture and align components, and also uses capillary forces to perform fine-alignment.…”

“…Our group has studied similar fully dry vibration-driven self-assembly methods in the micro scale [21,22,[26][27][28]. For materials that may be sensitive to exposure to water or other liquid environments, these all-dry assembly methods offer a feasible alternative to fluidic assembly.…”

Unified View of Robotic Microhandling and Self‐Assembly

“…Researchers have developed self-assembly methods that use a combination of two self-assembly techniques: geometrical shape recognition and capillary self-alignment [15]. This is a quite interesting technique because actually a two-stage positioning approach is used in this technology.…”

“…For example, in the work done by Fang and Bohringer [15], the feeding is not so trivial. First, the silicon parts with hydrophobic sides are placed in water.…”

Vision guided multi-probe assembly of 3D microstructures

“…where a is the contact radius from (9). With the initial 1 mN force, this works out to 38.82 µN of extra van der Waals force.…”