Concept for Using MID Technology for Advanced Packaging

The approach developed between the Institute of Micro Production Technology and LPKF Laser & Electronics AG follows a different strategy. The substrate itself is used as a functional part based on the technology of Molded Interconnected Devices (MID). The basis of this technology is a plastic substrate. In this work, a laser beam will be used as structuring tool by instigates an ablation of the organic compound. As a result of this ablation process the inorganic bulking agent will be uncovered. This agent can be metallized by electroless deposition of metals i.e. copper. This method made it possible to achieve near-surface structuring for the realization of trace parts, but through hole vias can also be achieved by combining the ablation process and electroless. To enhance the metallization an electrochemical process can be performed. For this new approach an injection molding process can be used to generate a planar plastic substrate in the shape and dimension of a conventional silicon wafer. In this case, the technology allows us to insert cavities into the substrate to create a 3D-micro-system instead of using etching technologies such as wet-chemical etching or deep reactive ion etching (DRIE). In detail, this technology approach offers the fabrication of e.g. lower coil systems with backside contact pads on injection molded plastic substrates. This means, that a many of necessary process steps for a micro system like a DC-DC transformer including the electrical contacts can be fabricated much easier and faster on a functional plastic substrate. In a clean-room environment, only a few process steps are required to complete the microsystem. The benefit of this approach is the reduction of fabrication steps inside a clean room and also the decrease of assembly steps. For example, wire bonding will be substituted completely by the created backside contact pads into the plastic substrate. It is also no longer necessary to integrate the system into a housing since the substrate itself will be the package after the microsystem is covered for example with a globe top sealing.