Issue link: https://iconnect007.uberflip.com/i/1484263
8 PCB007 MAGAZINE I NOVEMBER 2022 Nolan's Notes by Nolan Johnson, I-CONNECT007 UHDI: Raising Awareness and Interesting Questions It was over lunch on the second day of the recent IPC Symposium on Advanced Pack- aging when I asked a question that triggered an interesting discussion about advanced packaging and ultra high density intercon- nect (UHDI). While these two technologies are distinct, they are also symbiotic; it takes both to make either one successful. As the symposium delivered on its agenda, the inter- relationship between these two technologies became crystal clear. UHDI is the fabrication technology neces- sary if you want to manufacture the interposer subcomponents so critical to connecting the semiconductor chips to the enveloping pack- age. For the history of semiconductors, each component package contained one and only one chip. Advanced packaging uses sophisti- cated techniques to include and connect mul- tiple chips inside one package. is allows for a more modular approach to building up the fin- ished product. But how do the chips get connected inside? Interposers—super small fanout or intercon- nect features. Interposers provide the interim fanout steps from nanometer-scale IC pads to the ultimate goal of BGA solder balls lead- ing to the outside world. Interposers work a