By Victor A. Batinovich, Advanced Interconnect Solutions Revolution is a word that has been used often in the semiconductor industry. For the most part, it has been applied gratuitously and without merit. Too bad. Because today, when there is truly a revolution, the use of the word has lost much of its power and meaning. Nevertheless, it is a happy coincidence that the new millennium that began in January, and the widespread acceptance of wafer-level packaging arrived at about the same time. A quick review of this year's trade publications, conference proceedings and pending trade shows will bolster my point that a revolution in packaging has arrived. In the past five years, wafer-level packaging and flip-chip technology have advanced from rather interesting R&D propositions to mainstream packaging technologies. The number of companies now offering wafer-level packaging, flip-chip and other advanced, next-generation "packageless" formats has multiplied at a near record pace. Last year, there were a handful of companies able to provide WLP services, based on wafer bumping and redistribution. This year, those companies have been joined by more than a dozen familiar names, including industry giants Amkor Technology and Advanced Semiconductor Engineering. A Rush to WLP By next year, I expect that the overwhelming majority of traditional packaging foundries, at least those that have not completed doing so this year, will be rushing to add WLP to their existing services. Also by this time next year, the list of packaging foundries is likely to be divided into the "haves" and the "have nots"-those with bumping/redistribution capabilities and the others. The latter will not add bumping for reasons of capital cost or lack of process knowledge, or because they feel they have already found a secure niche.
For most veterans of the assembly, packaging and test portion of the semiconductor industry, the need to move forward in the chip-making food chain-toward the front end-is not unexpected, but it will be a challenge. We have dealt with die attach, wire bond, trim-and-form, and so on down the line for decades. Now we're obligated to select photolithography equipment, such as wafer steppers and contact aligners, to handle our WLP needs. Although it's early in the game, it appears that the independent device makers (IDMs) may entrust WLP to the independent packaging foundries, for the most part, instead of returning to the packaging business. The IDMs' trust in their packaging foundry partners will also carry a strong obligation to meet and exceed the specs that customers will demand for their most sophisticated products. I could produce 24-pin DIPS on the most basic of assembly lines. Not so for packaging done on the wafer. The manufacture of WLPs carries a certain risk for those new to the business, as well as substantial rewards. As the packaging industry begins to change course-as it decidedly will with WLP-we will need new equipment, new specs and new standards for the good of each competitor. Process Diversity We are now heading toward a Rubik's Cube of process diversity, since almost no standards exist to control the recipes employed in the wafer-level process. Although packaging foundries have been largely unrecognized for their part in the Herculean growth and amazing success of the semiconductor industry, that is likely to change as we produce devices far beyond yesterday's leading edge.
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