Jan, One place where Alloy-42 is routinely used, is in components which require some significant degree of hand assembly. Alloy-42's stiffness apparently tolerates this process better than the softer copper leads. Parts in this category include many of the SMT telecommunications impedance matching networks, hybrids, filters, 10 Base-T modules, etc. They usually contain toroid core transformers, whose windings must be hand soldered to the leadframe. Without a sufficient solder dip coating, and a warmer profile than normal, Alloy-42 parts can be quite difficult to solder. Bruce Tostevin Benchmark Electronics Inc. Hudson, NH ______________________________ Reply Separator _________________________________ Subject: [TN] leadframe materials Author: Jan Vercammen <[log in to unmask]> at 0UTG0ING Date: 3/16/98 3:15 PM hello, I have a few questions concerning package leadframe materials of integrated circuit packages. I have subscrided only recently to ChipNet and I will submit the same questions there. However, some of the subscribers on TechNet may have valuable info on the subject. -1- are non-copper materials (e.g.Invar, Kovar or Alloy-42 which are Fe-Ni alloys) still used alot for leadframe design of surface mount devices? What is the percentage of copper leadframes on the market today? -2- is there a finish used for copper leadframes and, if so, what materials are used and what is the covered thickness? -3- who has information on or can list references or literature on the complex permeability of non-copper leadframe materials ( (e.g.Invar, Kovar or Alloy-42) All help, however small is appreciated. regards, Jan Vercammen ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################