Issue link: https://iconnect007.uberflip.com/i/1484263
48 PCB007 MAGAZINE I NOVEMBER 2022 During an interview with IPC Chief Tech- nologist Matt Kelly regarding advanced pack- aging, we took a side trip into a discussion of UHDI: What is it? How is it different from printed circuit boards? Why are they so crit- ical to semiconductors? Matt details not only the challenges, but the payoffs of investing in UHDI technology. For advanced packaging, be sure to read our January 2023 issue, where we start off the new year with a deeper dive into this very relevant topic. Nolan Johnson: I have been hearing some PCB fabs in North America talking about their initial experimentation with making sub- strates. ey're saying that it is fundamentally different. Matt Kelly: Oh, absolutely. If you'd like, you can reference our November 2021 report. One of the key findings is that there has never been IC substrate capability in North America. We've had R&D, and pilot line capabilities, but noth- ing in significant volume. is is not a "bring it back" story, but rather "create it essentially for the first time." ere are different levels of substrates. Low end substrates are wire-bonded substrates— a chip wire-bonded to the substrate. If we are talking about line and spacing dimensions (as one metric), this is the easiest and the lowest tech substrate type. ese are in the range of 25-micron lines and spaces. Twenty-five microns is 1 mil. is is the range where people talk about "lines blur- The UHDI Spectrum Feature Interview by the I-Connect007 Editorial Team