Electrodeposition of 3D Interconnects for HEP Detectors (30b)

With the large channel counts and fine granularity of High Energy Physics detectors, there is an ever-increasing need for higher-density interconnects and integration. Conventional processes to fabricate high-density interconnect features of interest required for chip-to-chip, wafer-to-wafer and chip-to-wafer/substrate interconnection in the vertical stacking has been particularly difficult to scale and has remained at ~100- micron pitch. It is, therefore, critical to develop new technologies for reducing cost while increasing the density of high-resolution interconnects for integration of pixelated sensors to readout electronics. One of key approaches for high performance detectors involves high density 2D and 3D packaging and staking 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 or less. Thus, this SBIR program will develop a direct 3D printing of high-resolution interconnects (either as micro pillars and/or micro bumps) at room temperature that can be as small as 5-10 microns or as large as 50-100 micron in diameter and less than 25 microns in pitch. Phase I will develop and demonstrate a scalable, low-cost approach for fabricating high-density interconnects with the metals/alloys of interest to high energy physics instrumentation in minutes. In addition to controlling the resolution of interconnects to 5-10 µm in diameter and 20 µm in pitch, this process enables fine control over the microstructure of the deposited material to facilitate functional reliabilities of the interconnects for 3D integration. The preliminary plan will be developed to increase the yield and to reduce the manufacturing cost by developing a multi- nozzle 3D printing approach in Phase II. Additionally, the cost and performance metrics will be evaluated for use in scale-up and optimization activities in Phase II. The ability to directly print fine interconnects has the potential to enable manufacturing of more compact electronic assemblies. The direct print metal plating platform can work for any material that can be electrodeposited of interest to high energy physics instrumentation. The economic/social benefits from successful low-cost, high-yield, high-density interconnects fabrication approach is numerous and can be used in wide range of industries include healthcare, automotive, power transmission and electronics at an increasing rate. In addition to its use for advanced circuit fabrication used in electronics industries, the 3D printer can also impact small industries by providing them with alternate means of manufacturing specialized high-end products in the absence of the high vacuum equipment and clean room facilities for fabrication of functional metallic micro/nanostructures.