Board finishes for the EMS provider

摘要

Some new alternative PWB surface finishes have been entering the industry over the past few years. In order for any new board surface finish to be accepted for general use, it must be approved by the OEM as well as the EMS provider. This approval process begins with the chemical suppliers performing their own initial trials and tests. The supplier must approach potential EMS and OEM users to determine their interest in the finish. The EMS providers must run some trials to determine the advantages and disadvantages of the finish, compared to existing finishes. The OEM must determine if the finish is suitable for and compatible with any particular product application. This assessment must consider such items as whether the product requires: single reflow or multiple reflow assembly processes, precious metal contact, EMI shielding, press fit connection to a particular metallurgy, operation in a particular environment, etc. The board finish must be able to provide the EMS provider with a consistent assembly process that has a very high assembly yield. The resulting interconnections must provide a long term, reliable product for the OEM and end customer.