FROM: BRUCE HOUGHTON 27/552/844/TOR Phone (416) 448-5701 Tie 778-5701 Subject: (U) Electroless Ni/Au Self-life Ref: Question from George Milad, June 2 '95 George, Shelf-Life Expectancy for PWB's: -------------------------------- As a PWB assembler, we aim for a JIT process. With different PWB suppliers around the world, we most likely use more than 80% of our boards in 1 month. However, on small volume parts, we may order 6 months supply of the boards, at one time, to obtain an economical order quantity and cost. We also support/build spare parts for field support of existing product. We may order a minimum quantity of PWB's that will sit in our inventory for 2 years before we get an order to build the assembly. This applies to PWB's with HASL, OSP or other metallic finish. So, we look for at least 2 years shelf life before assembly and would like it to be longer. We support some products that were last manufactured 5 years ago. Think of the automotive industry, we, as drivers, still want to get spare parts 10 years after our car was first made. Accelerated Age Testing: ------------------------ I wish I knew that answer for this. The IPC age testing is applicable to HASL. An OSP coating will fail in hours, in the HASL Temperature and Humidity test, yet we successfully store OSP boards for a year or more, before they may have to be refinished. I don't think we will really know the answer until assemblers have stored boards, with various finishes, under their own storage conditions (these will differ a lot), for various periods of time and experience the results. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > I am looking for info on the shelf-life of boards with an > "Electroless Ni with Immersion Au" surface finish. > What is the expected Self-life of these boards, in the market > conditions of todays economy? > What "Accelerated Ageing Tests " are presently being requested > or run for this surface finish? > Thank you > George Milad > Atotech USA Inc Bruce Houghton Staff Engineer, Celestica, Inc. Internet: [log in to unmask]