Our silicon wafers fall into one of three general types: Prime Polished, Epitaxial, and Test/Monitor wafers. They are also differentiated by product or process type, and diameter; 100mm, 125mm, 150mm, 200mm, and 300mm.
Our silicon wafers vary in diameter, surface features (polished or epitaxial), composition, purity levels, crystal properties, and electrical properties. They are manufactured according to the precise specifications required by our customers. Semiconductor manufacturers require wafers of larger diameter and more stringent technical specifications in order to produce increasingly complex semiconductor devices such as the larger megabit memory chips and microprocessors.
Our customers have increased their focus on efficient semiconductor production processes because their manufacturing processes for semiconductor devices have become more expensive. Our customers make many semiconductor devices, or chips, from the same wafer, and all chips from a particular wafer are manufactured and processed simultaneously at each stage in the device manufacturing process. Because of this, larger-sized wafers allow for a greater throughput from the same semiconductor manufacturing process and allow semiconductor manufacturers to spread their fixed costs of production over a larger volume of finished products. For example, a 6-inch (150mm) wafer has a surface area of approximately 27.4 square inches, whereas an 8-inch (200mm) wafer has a surface area of approximately 48.7 square inches. Thus, the 8-inch wafer has approximately 78% more surface area than the 6-inch wafer. A 12-inch (300mm) wafer has a surface area of approximately 109.6 square inches or approximately 125% more surface area than an 8-inch wafer. Despite the industry's focus on larger diameter wafers, we continue to manufacture and sell a significant amount of 4-inch (100mm), 5-inch (125mm), and 6-inch (150mm) wafers.