Solderability testing is the method to provide a means of determining the solderability of device package terminations that are intended to be joined to another surface using SnPb or Pb-free solder for the attachment. The procedure, considered to be destructive, will test whether the packaging materials and processes used during the manufacturing operations produce a component that can be successfully soldered in the next level assembly.
There are two methods of solderability testing. Method 1 is known as “dip and look” which is for leaded and leadless terminations. This method includes pre-conditioning if applicable, the application of flux, and the immersion of the terminations into molten solder. Method 2 is a Surface Mount Process Simulation test. Both methods are followed by visual inspections for percent coverage.
Both MIL-STD-883F and test standard JESD22-B102D reference preconditioning for the purpose of assessing the solderability of device package terminations by the user. While optional, an accelerated precondition is generally used prior to solderability testing to simulate package shipment and storage. The options, to be agreed upon between the user and the supplier, include steam conditioning or dry bake.
The inspection and failure criteria requires
a) all flux to be removed prior to inspection of the terminal surface.
b) the devices to be inspected at 10x to 20x magnification.
c) the inspected area of each lead to have a minimum of 95% solder coverage.