Electrodeposition of 3D Interconnects for HEP Detectors

With large channel counts and fine granularity of high energy physics detectors, there is an increasing need of high-density interconnects for integration. Conventional processes to fabricate high-density interconnects are difficult to scale and has remained at ~100-micron pitch. It is critical to develop low-cost technologies for increasing the density of high-resolution interconnects for integration. Key approaches for high performance detectors involve high-density packaging of pixelated sensors to readout electronics. This approach requires connection of arrays of thinned integrated circuits to high resistivity silicon sensors with interconnect pitch of <25 microns. This program will develop a direct printing of high-resolution interconnects at room temperature that can be as small as 5-10 microns or as large as 50-100 micron in diameter and <25 microns in pitch. A scalable, low-cost printing of high-density interconnects with the metals/alloys of interest to high energy physics was developed. In addition to controlling the resolution of interconnects to 10 microns in diameter and 20 microns in pitch, the process enabled fine control over the microstructure of interconnects to facilitate functional reliabilities. A preliminary plan was developed to increase the yield and to reduce the manufacturing cost by developing a multi-nozzle array printing approach that will be built and tested in Phase II. The cost and performance metrics was evaluated for scale-up activities in Phase II. Direct print procedures will be optimized to produce targeted high-density interconnect metals/alloys of interest to high energy physics. High yield, low-cost production of multiple interconnects using a nozzle array will be demonstrated. Direct print system will be integrated into commercial x,y,z control stage to enable simultaneous validation and alignment for future high energy physics. Follow-on Phase IIB/III will transition the direct print system to integrate into commercial flip-chip bonders to produce high-density interconnects. The ability to directly print fine interconnects will enable manufacturing of compact electronics. The direct printing platform can work for any metals/alloys of interest to high energy physics. The economic/social benefits from successful high-density interconnects fabrication approach are numerous and can be used in industries including healthcare, automotive, power transmission, etc. The approach can also impact small industries by providing them with alternate means of manufacturing high-value products in the absence of the high vacuum and clean room facilities.