What is the preferred surface finish for PWB's with PBGA packages? I have been looking at some published industry data regarding PWA assemblies with plastic BGA's and so far all have had HASL surface finish and very little data on OSP (organic Solderability Preservatives such as Entek) coated boards. Has anyone had any OSP coated (Entek 106) mother board designs with BGA packages in production? What are the pro and con's with HASL Vs. ENTEK for BGA assembly? Using Entek boards, what kind of flux is better to use, NO CLEAN or water soluble? The preferred surface finish for assembling fine pitch components has become Entek (or Entek equivalent) for better coplanarity criteria, but is there a danger using Entek boards for BGA assembly? I would greatly appreciate any information you can share with me. [log in to unmask] (800) 289-3355 EXT 85408 or 512-728-5408 direct line Thanks, Gita