Current hermetic microelectronics packaging technology is based on either metal or ceramic materials that are heavier and more expensive in the end product than a polymer.  In some components, the packaging is up to 85 percent of the total component cost.  In order to build advanced, but cost-effective systems, the cost of hermetic packaging must be reduced significantly.  Liquid crystal polymer (LCP) packaging can achieve these goals. In a recent proposal, the U.S. Air Force asked us to:

•  Develop a lightweight, low-cost hermetic, or near hermetic, packaging solution.
•  Design this packaging solution for optoelectronic communication modules/components.
•  Fabricate test samples and characterize package performance.

We used proprietary LCP electronics packaging technology to meet all of the requested deliverables.  Hermetic LCP packages that incorporate optical windows, micro-lens arrays, and optical fiber feed throughs were designed, fabricated, and tested.  This patented technology utilizes an LCP PCB to accommodate the electrical feed throughs (leadframe or BGA). LCP substrates have excellent dielectric properties (2.9 dielectric constant, 0.002 loss tangent up to 75GHz) allowing the integration of high-speed feed throughs within the substrate itself. Package components and circuitry were protected in the cavity package by attaching a lid assembly to the base substrate. The lids were injection molded LCP which can be thermoplastically welded or solder sealed (metallized lids) to the LCP interconnect substrate.

Improved LCP-based packaging technologies have wide application where cost and weight are important issues.  Foster-Miller’s LCP packages have passed MIL-spec 883, helium leak test and are currently being tested in a number of extreme environmental conditions to characterize cyclic fatigue, high temperature, humidity, and pressure conditions.

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