Advanced Unidirectional Compliant Electronic Interconnect for Reliable Ultrafine Pitch Microelectronic Systems

Complex electronic systems especially for defense applications depend on the integration of fine and ultrafine pitch (< 50 micron approaching 10 microns) commercially available ASIC, SoC, and Field Programmable Gate Array (FPGA) onto a myriad of substrates. Being able to manufacture, assemble and source components and assemblies domestically has become increasingly important with national security at stake and several of the manufacturing capabilities for components and assembly residing outside the continental USA. As component pitches continue to decrease, one of the key issues with traditional approaches to electronic interconnects, utilizing solder and solder bumps, is the limitations imposed with forming reliable solder joints at fine and ultrafine pitch geometries. Insufficient amounts of solder and the difficulty in depositing adequate volumes of solder paste for enabling reliable interconnection makes it very challenging. Adding bumps at the die level is much more difficult at fine pitch (<50um). Interconnect technology that could eliminate bumping, would greatly enhance integration. In order to enhance the reliability of interconnects, especially at ultrafine pitch geometries, epoxy underfill becomes essential to reduce the strain on the solder joint. This project is to demonstrate ZTACH® ACE, a pressure-less z-axis conductive epoxy for bonding fine and ultrafine pitch chip devices and ASICs. SunRay has developed ZTACH to address current interconnect technology manufacturing limitations for high density interconnects, fine-pitch applications that include sensitivity to pressure and/or high temperatures, and withstands harsh environments such as high radiation exposure, cryogenic temperatures and high magnetic field exposure. To accommodate advanced die-scale packaging solutions such as flip chip onto advanced interposers and “package-less” solutions such as fan out wafer level packaging (FOWLP), the team is proposing a solderless, novel anisotropic conductive epoxy (ZTACH® ACE) based solution developed in the USA and currently available to support manufacturing primarily within the US. This technology has a proven track record of successful and reliable interconnection as a solder alternative for a myriad of applications up to 100- micron pitch and also eliminates the need for bumping. The advanced unidirectional nature of ZTACH® ACE interconnect has also proven to be multi-functional, serving both for electrical interconnection and thermal dissipation. The team proposes to work with multiple AF directorates and other DoD suppliers/customers to understand the various applications for this technology, and build demonstration test vehicles to highlight its feasibility. The success of this initiative will enable Phase II and III grant opportunities to further investigate and study various manufacturing and reliability aspects associated with this technology for DoD applications.