Cu% spec for lead free HASL surface finish

There is no specification for lead-free HASL. You can use any lead-free solderability protection that meets your customer requirements. Use IPC-9701 �Performance Test Methods and Qualification Requirements for Surface Mount Solder Attachments� to assure reliability with accelerated testing that is relatively close to the field operating conditions. While IPC-9701 was not developed with lead-free solders in mind, the principles underlying the standard are applicable equally to lead-free solders. Appendix B provides recommended changes to the thermal cycling recipes given in 9701A for lead-free solder joints.

As a bonus ... IPC-4101B "Specification for Base Materials for Rigid and Multilayer Printed Boards" lists specification sheets that identify material requirements for �lead-free FR-4� laminates. Also, these sheets outline qualification and periodic conformance requirements not found currently for other FR-4 base materials, including Td, T260, T288, T300 and Z-axis expansion. The lead-free specification sheets are: * IPC-4101B/99. High Tg FR-4, inorganic fillers, brominated flame retardant * IPC-4101B/101. Low Tg FR-4, inorganic fillers, brominated flame retardant * IPC-4101B/121. Low Tg FR-4, no fillers, brominated flame retardant * IPC-4101B/124. High Tg FR-4, no fillers, brominated flame retardant * IPC-4101B/126. Very high Tg, inorganic fillers, brominated flame retardant * IPC-4101B/129. Very high Tg, no fillers, brominated flame retardant

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