Ultra low cost wafer level via filling and interconnection using conductive polymer

Abstract

Devices for consumers like camera phones are essentially driven by the cost and performances. In that scope, several new key technologies are requested to achieve a complete active waferlevel camera (with autofocus or zoom). A low cost vias interconnection has to be developed and conductive polymer is an attractive solution to overcome this challenge.In this paper we describe new technology to fill insulated vias and perform interconnection with conductive polymer with screen printing equipment.In the first part, process flow compatible with waferlevel camera integration is presented to make vias and metal routing. Then, polymer characterizations were done to evaluate Dupont CB100 resistivity and contact resistance with our metallization.Electrical contacts have been demonstrated with values about 100m and proflow configuration.Thermal cycling between -40°C to +85°C was performed successfully and no variation was observed even after 300 cycles. These results are very promising and give us a first feedback on this technology ability to withstand classical consumer product environmental tests.

3-D Integration and Through-Silicon Vias in MEMS and Microsensors

“…A capillary-effect-based solder pump method has been developed, in which solder balls are filled into throughholes, and after reflow, a solder column is formed as the TSV conductor [138]. Conductive polymers such as Dupont CB100 have also been used as TSV conductors, being filled into through-holes with a screen printing machine [139]. Their sheet resistance has been measured at 0.13 ± 0.02 / .…”