A Case Study of Ultra-Leach Resistant Thick Film Conductors for Non-Magnetic Applications

Abstract

Today, designers of SMT electronics are being asked to achieve more while designing around new technical constraints. Many times these constraints force designers to sacrifice commercial advantages of their designs in order to achieve performance goals or vice-versa. This is made worse when industries and regulations impose restrictions on materials such as lead free, high temperature processing, low-PIM or non-magnetic requirements. Often, the choice comes down to either using high performance components that are expensive and sensitive to processing or robust components that either offer reduced performance or are restricted for use due to material content. This is especially true of surface-mount technology components common to electronics manufacturing where solder processing requirements are found. While typical Ag/Pt thick film conductors are a perfect choice for sensitive applications requiring robust processing, they cannot match processing parameters similar to very high leaching resistant materials like nickel barrier. Since nickel barrier is inherently ferro-resonant, some applications cannot be realized without a new material approach. Components manufactured for use in these sensitive, yet demanding applications have now been produced using an Ultra Leach Resistant (ULR) processing of Ag/Pt thick film. The performance of components produced using this ULR material and process have been evaluated for survivability in solder environments to study the resistance to leaching compared to nickel barrier and traditional “leach resistant” materials available today. The results indicate that it is possible to achieve nickel-barrier-like results without ferro-resonant properties using a “ULR” material and process.