High-density interconnect (HDI) fabrication is the fastest growing segment of the printed circuit industry. From its simple start in 1985 for Hewlett-Packard's first 32-bit computer (the Finstrate) to today's large client servers with 36 sequentially laminated layers and stacked microvias, HDI/microvia technologies are the PCB architectures of the future. Smaller component pitches, larger ASICS and FPGAs with more I/O, embedded passives and higher frequencies with shrinking rise-times all require smaller PCB features, driving the need for HDI/microvia. This paper outlines the six simple processes in PCB fabrication that have to be improved in order to successfully build highly reliable HDI/microvia boards.
The conclusion of this paper emphasizes the business opportunities and challenges faced by management in starting and developing the HDI fabrication business including the engineering challenges of improving yields.