Additive manufacturing of robust, nonplanar electrical interconnects

Optomecs proposed innovation is a direct-write additive manufacturing process, creating 25um electrical interconnects that can accommodate 3D steps and are terminated in a wire bond pad. These printed interconnects will minimize packaging space by replacing traditional wire bonds with conformal fan-out electrodes. This additive manufacturing proposal is a science enabling technology for the next strategic class of astrophysics missions, as stated in scope description of solicitation S12.06. Improving the packaging for large format multishutter arrays is a goal relevant to several NASA missions, including the Large UV/Optical/IR Surveyor (LUVOIR) and the Habitable Exoplanet Observatory (HabEx) missions. Optomecs innovation uses metal nanoparticle dispersions or inks to create pad and trace patterns, and these patterns are functionalized by sintering the metal nanoparticles at low temperatures or with a laser to make electrically conductive conformal interconnects. The Aerosol Jet technology creates a high velocity stream of tightly collimated droplets, which means that liquid inks can easily be jetted in precise patterns. Tilting the jetting head relative to the flat substrate gives direct vision of both horizontal surfaces and vertical sidewalls, enabling interconnect printing over steps up to 1.5mm high and beyond. The tight collimation of the Aerosol Jet stream also means that Optomec can create very fine features, 25um size and smaller. ThePhase II effort will focuson prototyping Microshutter Array (MSA) interconnects packages and testing these packages for reliability in harsh conditions. The project willfurther optimizethe printable materials and sintering processes to facilitate robust thermo-mechanical and electrical interconnections. Optomec’s innovation is to replace the traditional vertical wire loops of wedge wire bonding with a conformal electrical interconnect, printed using Aerosol Jet.  Although it is a mature interconnect technology, wedge wire bond loops have limited maximum lengths, minimum pad sizes, and minimum loop height above the packaged device.  The conformal printed interconnect directly eliminates the 150- 400um of vertical open space needed above the silicon device for wire loops, and it enables higher density interconnects, smaller than 25um features (50um pitch).  Optomec’s innovation can accommodate millimeter-scale height changes along the conductive path, for example, between the active device and the substrate, and by reducing the package size, we will increase flexibility of scientific instrument design.  Conformal interconnects are advantageous anywhere space and density are important, but this innovation is immediately relevant for packaging microshutter arrays (MSA) used in spectrographic missions. The main objective of the Phase 2 work is to produce robust, 25um wide, electrical interconnects that conform to 3D steps and are terminated in wire bond pads.  These printed interconnects include multiple metals, namely, silver and gold, forming different portions of the electrical traces, and a supporting dielectric fillet.  At least three dielectric materials will be tested with the goal of downselecting one that best meets reliability standards.  Cleaning procedures and ink additives will be developed to optimize adhesion and minimize contact resistance between the printed metal and die contact pads.  Finally,  materials processing protocols will be developed to include UV, thermal, and laser sintering.  3D interconnect test coupons will be rigorously tested under a variety of environmental conditions including thermal cycling, high- and low-temperature storage, vibration, and damp heat.  In addition to the written and verbal milestone reporting, Optomec will deliver at least 10 completed MSA for characterization at NASA Goddard Space Flight Center.  

The printed interconnect innovation is directly relevant to several NASA programs.  It will reduce space requirements and improve packaging reliability for next-generation microshutter arrays, such as those needed for the Large UV/Optical/IR Surveyor(LUVOIR), the Habitable Exoplanet Observatory (HabEx), and the Cosmic Evolution Through UV Spectroscopy (CETUS) missions.  It has the potential to reduce the size and weight of electronic assemblies used in a wide range of other projects. Conformal 3D printed interconnects have a wide variety of potential commercial applications.  Two immediate markets for this innovation are in RF packaging, where it can improve RF transmission efficiency at very high frequencies used by defense and aerospace agencies, and in reducing size and increasing packing density in micro-LED applications.

This is early/mid-stage (TRL 3) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.