From batch to single-wafer processing
In order to understand these trends, and the issues of modularity and standard-setting that attend them, one needs to look more closely at the semiconductor production process.4 The traditional approach to the mass production of semiconductors has been batch processing. Silicon wafers, each containing what will become many separate chips, move through the various steps in batches, queuing up when necessary in work-in-process (WIP) inventories. For example, a large vertical furnace may process more than 100 wafers at a time. All high-volume ‘fabs’—as semiconductor production lines are now invariably called —currently use batch techniques, and these have worked well through the current DRAM generations.