Napa, California–Nov. 15, 2000–Paul Totta, an IBM fellow emeritus, treated attendees of the IEEE KGD Packaging and Test Workshop to some insights into IBM’s flip-chip history and future plans.
In the keynote speech to kick off the event, held recently in Napa, CA, Totta, who has been involved in IBM’s flip-chip programs since 1970, showed IBM’s Power4 chip, a GHz microprocessor targeting the next generation of massively parallel web servers. The 20mm — 20mm chip has 7018 bumps at 0.2mm pitch. The chip had “only” 5500 bumps when it was first discussed at the Microprocessor Forum last year, but additional bumps were added to provide mechanical support for the heatsinking structure attached to the 150W chip. The 170 million transistors with 0.18 micron minimum features are connected by seven levels of copper interconnect, although the Power4 does not incorporate a low-k dielectric yet. Totta expressed concern about the reliability of such materials at this point for the long lifetimes and reliability needed for the targeted applications. The server with the Power4 chip will come out next year, and Totta said, “If IBM doesn’t win that battle with Intel for this market, then IBM will get out of the device business.” He might be overstating the outcome, but it clearly indicates the importance of the product.
Other upcoming applications of IBM’s flip-chip products include the Microdrive, a tiny disk drive that will appear in GPS units and digital cameras next year. The 43mm — 36mm — 5mm 1GB drive is made possible by several flip-chip components, including a flip-chip-on-flex pre-amp. The unit weighs the same as one AA battery, according to Totta, and it will compete with memory cards.
A bit farther out on the roadmap is a Petaflop (i.e., 1000 Teraflop or 1,000,000 Gigaflop) computer called “Blue Gene.” It will be used for biological calculations and incorporate 64 towers with eight boards each, with 64, 32-Gigaflop flip-chip ICs on each board. The product is five years and $100 million away.
On the historical side, Totta told the audience the famous “C4” designation for their flip-chip technology originally had the “4” as a superscript, but the IBM typists of the 1970s rebelled and turned it into C4, illustrating the power of an administrative support staff.
By Jeff Demmin.