Ask the Experts
October 31, 2011

CEM1 Laminate Issues

We use CEM1 laminate. The laminate bubbles and de-laminates during the reflow process. Is CEM1 laminate designed for the higher temperatures of lead free solder? The boards are stored sealed with a desiccant inside the package. We have tried pre-baking the boards for a couple of hours at 100 degrees C, but don't see much improvement. I know this could be cured by changing to FR4, but the cost is a concern. Is there a solution?

A. N.

Expert Panel Responses

CEM1 is a paper-core material laminated with a thin layer of fiberglass. It is not usually able to withstand higher reflow temperatures associated with lead-free solder processing, in fact, it is even problematic for 63/37 solder processing and is typically only used for single-layer PWBs. I sure wish I could provide some good news. If I knew more about the CCA, I could possibly provide you with alternative processing ideas.

Richard D. Stadem
Advanced Engineer/Scientist
General Dynamics
Richard D. Stadem is an advanced engineer/scientist for General Dynamics and is also a consulting engineer for other companies. He has 38 years of engineering experience having worked for Honeywell, ADC, Pemstar (now Benchmark), Analog Technologies, and General Dynamics.
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