CircuiTree - July 2008 - (Page 31)

[ CircuiTree 20-Year Retrospective ] its focus on the future. In the late ‘90s, the Japan groups came together to develop a Jisso roadmap. Jisso is a word that signiﬁes building blocks for combining technology elements. The Jisso roadmap is a Japanese technology roadmap and a system integrator encompassing a wide range of technology ﬁelds. It is a macro viewpoint encompassing areas such as function, conﬁguration, manufacturing design, interconnect technology, and cooling technology. Jisso technology, taken in the meaning of mounting and assembly, is technology that forms a system for highly integrated design of electronic systems and interconnection of device subsystems. The uniqueness of the Jisso roadmap results from its focus on the total packaging solution. The roadmap contains a level of detail on technology attributes that other roadmaps do not have. Figure 2 shows the concept of the Jisso roadmap originally published in 1999. rule; through-hole discrete components were easy to combine into logic functions to create the computer logic needed to do productive mathematical computation. With the invention of the transistor, semiconductor technology became the growing media for the many products that are in use today. Once the concept of converting analog signal technology into its digital signal equivalent took hold, there was no stopping the changes that would take place in the last several decades. The component technology also changed in this time period. Initially there were several package types that could house the semiconductor integration that went beyond the single transistor. The dual in line package (DIP) became the darling of the industry. It was easy to design with this package; it was easy to fabricate boards into which the DIPs were assembled; and it was easy to inspect or test for defective joints. Because through-hole could no longer meet industry needs for functionality, new concepts needed to evolve. In all this upheaval, the idea of moving away from a through-hole to a surface mountable component was the major emphasis that would allow a paradigm shift in the way electronics were produced. Figure 4 shows the revolution of component style and, thus, design, assembly, and testing concepts had to move with those conditions. assembly. The military funded the development of the leadless ceramic chip carrier (LCCC). The LCCC used castellations, which were intended to let the solder wick up the sides of the device and form the attachment solder joints. As the package grew in size and continued to be mounted on organic glass epoxy printed boards, the variation in the coefﬁcient of thermal expansion between the component and the mounting structure had a dramatic effect on the reliability of the solder joint. Almost every article in the technical journals talked about solder joint cracks and how many thermal cycles the LCCC joints could survive. Not every company in the world suffered this pain. Asia was mounting small components and had moved ahead in the automation of the placement and attachment process. Europe played a major role in the development of a small outline integrated circuit, which was a plastic leaded package with similar expansion properties to the mounting structure. It was a time of learning and a time of much misinformation. In this learning environment, the Tri-Services needed to identify a packing concept for the future so the Air Force funded the Manufacturing Technology (ManTech) program intended to develop the ideal method of packaging military hardware. Figure 2 Jisso Packaging Concepts In an attempt to have most of the Japanese organizations involved in the roadmap development, the JEITA leadership asked some of the other groups in Japan to participate. The Jisso roadmap became a form of marketing that not only showed where the industry stood but what the challenges were according to the participants of the roadmap development team. Figure 3 shows the Jisso participation structure. Figure 3 Jisso Roadmap Participation Structure Figure 4 Evolution and Revolution of Component Package Styles Technology Changes Life was simple in early days of the industry. Single- and double-sided boards were the Because the U.S. military was a large customer of electronic hardware, it funded several studies and was a driver toward robust conditions in the use of the electronic SMT The attention to the mounting concepts proved successful because the assembly ensured that the parts were not jammed down to the mounting surface. The industry circuitree.com • July 2008 31 http://circuitree.com

Table of Contents Feed for the Digital Edition of CircuiTree - July 2008

CircuiTree - July 2008 Contents My Line Industry Review Tech Talk Flexible Thinking Toward a PCB Production Floor Metric for Go/No Go Testing of Lossy High-Speed Transmission Lines Intelligent Design 20-Year Retrospective Ask the Flexperts Environmentally Speaking BPA Growth Curves Considering Design Variants to Maximize Process Efficiency Market Outlook Technical Product Spotlights Classified Ads Upcoming Events Ad Index

CircuiTree - July 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.