ABC modeling: advanced features [semiconductor manufacturing]

Abstract

At IBM in Essex Junction, Vermont, an enhanced ABC model is being used not only to assign costs to wafers, but in several new ways that have enabled analysis across multiple dimensions. The model is being used to aid cost reduction activities by providing wafer cost breakdown by process type (e.g., expose, deposition, etch, cleans, measurement), by element (e.g., depreciation, chemicals, staffing, occupancy), by level (e.g., poly gate, metal, via), and by equipment state (e.g., productive or idle). These new cost breakdowns allow a more complete understanding of the cost contribution of different factors and therefore enable proper focus with regard to cost reduction activities and productivity studies. For example, wafer costs broken down by masking layer show that critical levels (i.e., critical in terms of printing requirements) are the most expensive to manufacture. This approach changes classical activity-based-costing (ABC) from a financial tool to a managerial tool for assessing factory dynamics.