The Evolution of ICT: PCB Technologies, Test Philosophies, and Manufacturing Business Models Are Driving In-Circuit Test Evolution and Innovations

摘要

Many manufacturers employ one or more In-Circuit Test (ICT) systems in their PCB manufacturing facilities to help them detect manufacturing process and component defects. These "bed-of-nails" electrical test systems are highly valued for providing the qualities of simple program generation, high fault coverage, fast test throughput, low false fail rates, and exceptional diagnostic accuracy as compared to other available test and inspection techniques. Advancements in PCB technologies, along with changing test philosophies and manufacturing business models in recent years have created new and diverse requirements for manufacturers of in-circuit test systems. Particular challenges that ICT manufacturers have had to address include the erosion of test point access in certain product sectors; the progression of ultra-low voltage components; the variable test requirements of different product applications; the varying test philosophies of different market segments and different manufacturing regions; and the demanding throughput requirements of high volume production facilities. This paper highlights how in-circuit test systems have evolved in recent years to include innovations and advancements to address these challenges and trends. Topics that will be covered include boundary scan and functional test integration strategies; advancements in vectorless test techniques; incorporation of limited access electrical test techniques; test strategy analysis tools; high accuracy pin drivers and sensors; concurrent test throughput improvement options; scalable test performance capability architecture; and program development accelerators. The paper describes how these new ICT advancements contribute to lowering overall manufacturing test costs by improving the fault coverage, reliability, and throughput of in-circuit production tests.