Maskless Additive Fine-Pitch Interconnects and Wire Bond Replacement for Advanced Packaging

Advanced packaging and heterogeneous integration demand ever-finer interconnect pitches, yet conventional lithography-based and subtractive approaches impose strict substrate flatness requirements, involve 20+ process steps, and drive up cost and cycle time. We present an additive, maskless approach based on Scrona’s inklogic multi-nozzle MEMS electrohydrodynamic (EHD) printhead platform, which uniquely combines sub-micron resolution, high throughput, and material flexibility for advanced packaging applications.

We demonstrate three complementary capabilities that simplify today’s workflows. First, direct printing of photoresist at sub-10 µm resolution removes the need for spin-coating, mask exposure, and development. Second, direct seed-layer deposition with <2 µm resolution eliminates blanket plating and etching. Third, direct metallization using MOD and nanoparticle inks enables fully additive build-up of conductive structures, including redistribution layers (RDL) and vertical interconnects, without masks or subtractive steps.

Crucially, this process is not limited to planar substrates but extends to 2.5D and 3D topographies, supporting conformal printing across steps, vias, and trenches. This capability unlocks new approaches to wire bond replacement, such as guiding droplets along vertical chip edges to form fine-pitch interconnects or bridging across resin-filled trenches to connect neighboring dies. Such direct-write architectures combine the simplicity of wire bonding with the density and performance of RDL and bump interconnects.

Beyond electrical interconnects, Scrona’s additive platform also addresses optical packaging challenges. By directly dispensing and structuring optical polymers, quantum dot inks, and other photonic materials, the technology supports gap-filling in optical packages and enables the formation of precision optical features. Furthermore, printed optical layers can be patterned or restructured via nanoimprint lithography and related techniques, offering new integration routes for AR/VR optics, photonic interposers, and high-speed optical interconnects.

Unlike prior direct-write attempts, which have struggled with throughput and scalability, Scrona’s platform uniquely leverages multi-nozzle MEMS printheads to deliver both high resolution and economic viability. These results highlight a pathway toward sustainable, digital-first interconnect and optical packaging that reduces process steps, lowers chemical usage, and enables new device architectures in fan-out, chiplet, and panel-level integration.