Issues for the larger diameter epitaxial wafer
In order to establish the epitaxial wafer as the main substrate for semiconductor devices produced on large diameter wafers over 300 mm, the epitaxial wafer must satisfy stringent requirements in terms of both quality and costs. Before proceeding with 400 mm diameter epitaxial wafer development, we reviewed all technical issues for larger diameter epitaxial wafer development, and then determined an approach that adequately addressed the major technical hurdles. Our first technical accomplishment was the development of a low-temperature SiH4 gas epitaxial growth process, followed by the design, manufacture, and installation of a single-wafer spin cleaner and original epitaxial furnace for 400 mm diameter wafers. We were successful in growing the entire surface of a 400 mm diameter wafer by a series of processes that were conducted with an appropriate combination of this equipment. Our challenge has opened the way to high-quality and low-cost epitaxial wafer manufacturing.
Fig. 1. The flow of common and developed processes.
Fig. 2. Schematic diagram of the SSi original epitaxial furnace.
Fig. 3. X-ray topography of a 400 mm epitaxial wafer.
Fig. 4. Epitaxial growth rate distribution along the gas flow direction.
Source: Microelectronic Engineering