Aerosol Jet® Printing of High Density, 3-D Interconnects for Multi-Chip Packaging

Abstract

Optomec's patented Aerosol Jet technology is a maskless, non-contact material deposition system used to enable 3-dimensional semiconductor packaging. This presentation highlights results of printing high density, 3-D interconnects on stacked die modules which incorporate video, communication and memory chips. Such packages are critical for meeting the increasing functional requirements of SmartPhones, personal entertainment, and other mobile devices. The Aerosol Jet system is used to deposit silver nanoparticle ink connections along the staircase sidewall of staggered multi-chip die stacks. High aspect ratio interconnects with 30-micron line width and greater than 10-micron line height are demonstrated at a pitch of 61-microns. After printing, the silver inks are cured at ~200°C for ~30 minutes, which gives interconnect resistances below one-Ohm (< 5 micron Ohm*cm). The stacks can include up to 8 die, with a total stack height below 1 mm. The printing system has a working distance of several mm which means that no Z-height adjustments are required for the interconnect printing. Multiplexed print nozzles are used to achieve production throughputs of greater than two interconnects per second per nozzle. Based on cost and functional advantages, the Aerosol Jet process is emerging as an effective alternative to traditional wire bond and through-silicon-via (TSV) technologies.