Fully Printed 3D Interconnects: Reducing Semiconductor Package Size and Reducing Manufacturing Complexity
Author: Bryan Germann Company: Optomec Date Published: 10/14/2018
Abstract: Aerosol Jet printed electronics enables high performance electrical 3D interconnect solutions for single or multiple die stacks reducing overall package height. Interconnects on die stacks of 8 or more die, with a total stack height of ~ 1 mm have been demonstrated. High aspect ratio interconnects with <30-micron line width and 6-micron line heights at sub 60-micron pitches resistivity < 4.8*10-8 ohm*m are shown. If required, Aerosol Jet is used to deposit dielectric of other insulating materials over printed interconnects. Production throughputs of greater than two interconnects per second depositing Ag or Cu nanoparticle ink connections on both single and staggered multi-chip die stacks have been realized. Material viscosities range from 1 to 500cP. Interconnect depositions are achieved through the atomization of liquid material into 1 to 5-micron droplets that are entrained in a gas stream and delivered to the print head. An annular flow of clean gas is introduced around the aerosol stream to focus the droplets which are tightly collimated through the print head. The combined gas streams exit the print head through a converging nozzle that compresses the aerosol stream. The jet of droplets exits the print head at high velocity (~50 m/s) and impinge upon the substrate.