Additive Manufacturing Of Interposers With Curved Vias For Microelectronics Packaging

Advances in digital light processing now enable additive micro-manufacturing of parts on the centimeter scale, with features on the order of 10 μm. In this study, ceramic interposers were printed containing arrays of vias (holes), with diameters and pitches as small as 9 μm and 18 μm, respectively. The vias were subsequently metallized by melt infiltration to provide electric pathways. This technology enables unprecedented via routing, including curved and angled vias, offering new packaging options for the 3D integration of microelectronic subsystems. Two different interposer designs were demonstrated: 1) a curved interposer intended to connect a curved infrared detector with a planar read-out integrated circuit (ROIC); and 2) a fan-out interposer that spreads the pitch of an array of vias from 60 μm to 220 μm. These interposers require thousands of curved and angled vias, respectively, that cannot be realized using conventional microelectronics processing approaches. 

• Ceramic interposers with curved vias at pitches as small as 18 µm were 3D printed.
• Curved vias with aspect ratios of 150:1 were metallized.
• An interposer to connect a curved infrared detector was fabricated
• A fan-out interposer that spreads the pitch of an array of vias was fabricated

1. Introduction
2. Materials and methods
3. Results
4. Interposer demonstrations
5. Discussion
6. Conclusion