To give an overview of the problems that can occur with base laminate materials when converting to lead‐free soldering and to give guidance on possible solutions.
The paper contains a number of correlations between different physical measurements and their impact on real‐life processing conditions. The problem areas are highlighted and the corrective actions that need to be taken with base materials are described.
Results suggest that conventional FR4 resins might still be suitable for standard lead‐free applications that require only a few reflow cycles. However, with the growing complexity of board designs and the increasing number of solder cycles, better thermally resistant products are necessary. Other key resin parameters such as adhesion or toughness are also essential to enhance reliability.
The value of the paper lies in its provision of guidance on critical base material properties. It describes the change in physical properties that laminates will experience when moving to the higher temperatures needed for facilitate lead‐free assembly. Selection criteria for base materials are given that will help to minimise the impact of these higher temperatures.
