Search results

The work of David John Farmer has been recognized as critical to the Public Policy and Administration canon. Its impact has been far-reaching both geographically because of its international application and theoretically because of the vast array of public administration challenges it can help resolve. This paper uses the concepts of rhizomatic thinking and reflexive interpretation to describe Farmerʼs work. And because a critical piece of Farmerʼs work is a bridging of the gap between theory and practice, it formally introduces Farmerʼs research approach as Farmerʼs Method. This article is intended to serve as a useful tool for students, practitioners, and theorists in understanding the vast contributions of David John Farmer and the practical application of his work.

The purpose of this paper is to present an overview of the evolution of organic solderability preservatives (OSP) technology from a temporary anti‐tarnish to an approved process for the lead‐free assembly of high‐reliability printed circuit boards (PCBs).

As this is an informational paper, the main approach was to compare and contrast various types of OSP molecules and their fitness for use.

The active ingredient of an OSP is one of the most important ingredients that can help to improve the heat resistance, which becomes much more important in conjunction with lead‐free solder. The latest OSP shows excellent stability, even at more than the peak reflow temperatures used with lead‐free solders. The success of any OSP process is highly correlated to process control and maintenance and OSP formulations are not created equal. The thickness of the film is only one difference. However, the key differentiators for OSP coatings are the overall ability of the organic film to resist oxygen penetration and humidity; and withstand the higher temperatures of lead‐free assembly. The author suggests that original equipment manufacturer (OEMs), contract manufacturers and PCB fabricators perform testing and qualification of OSPs using industry‐accepted reliability and solderability testing methods.

This work represents the author's extensive experience with OSP technology, as well as the results of a collective collaboration with Shikoku Chemical Corporation. The findings represent reliability and solderability testing carried out in various manufacturing sites including cooperation with certain OEMs that are users of circuits fabricated with OSP technology.

This paper details how critical advances in OSP technology have enabled improvements in solderability and reliability over earlier commercial generations and have further enhanced the solderability of lead‐free assemblies.