SELECTING LAMINATE MATERIALS FOR LEAD-FREE ASSEMBLY APPLICATIONS
Author: Edward Kelley Company: Isola Group Date Published: 6/21/2007
Abstract: The July, 2006 RoHS deadline has come and gone. Success in preparation for this deadline has varied greatly. For some, it was a relatively seamless transition. For others, it could not have been more painful. And for those with exemptions that continue over the next few years, there is still a great deal of work to be done. Indeed, the segments that currently have exemptions are generally the more complex applications where product reliability is most critical. In addition, these segments are facing pressure to comply ahead of the deadlines due to component availability issues and constraints within the EMS industry. These ongoing transitions will be the most challenging in terms of base material selection and qualification due to the designs of the printed circuit boards (PCBs), the complexity of assembly and the requirements for long-term reliability and electrical performance. The purpose of this paper is to summarize the impact of lead-free assembly on laminate materials, discuss critical laminate properties, identify candidate materials, and to introduce a laminate material selection approach designed to help answer the question regarding what laminate material should be considered for a given application. This paper will build upon experience with lead-free assembly compatible materials, reporting both the benefits and issues that have arisen with the current generation of products. Characteristics of new material offerings that address some of these issues will also be presented.