For 30+ years, Warren Flack has significantly influenced the global advanced packaging (AP) lithography arena with his expertise spanning dry-etching for silicon technologies, optical and electron-beam lithography. Sporting a quiet demeanor, Dr. Flack is much appreciated by customers and colleagues for his valued insights on AP process development and applications. He was on the 1980s VHSIC program that developed the first 0.5µm CMOS process. During the 1990s, he led pioneering design efforts to apply lithography in AP for flip chip and Cu pillars. Dr. Flack received his bachelors and masters degrees in chemical engineering from Georgia Institute of Technology and his Ph.D. with a thesis on optical lithography modeling from University of California, Berkeley. He has five U.S. patents in lithography and has authored 100+ technical articles, including dual-side alignment for TSVs, field stitching for large area interposers and recent work on 1µm RDL lithography for fan-out applications.