Unformatted text preview: 2% is the capacity loading for the model run with 100% of volume dedicated to Product A. 3. Calculate the change in capacity-loading of that tool group if one wafer is shifted from the lightest-loading product to the heaviest-loading. In the example above, this is .344 - .214 = .130 percentage points. This is the change in capacity loading per wafer shifted—the net percentage points of Tool Group X capacity that are used up when one wafer is shifted from Product A to Product C. (Note: if the model has setups and/or unitbased tool downtimes, the calculations of paragraphs 2 and 3 are not constant for different volumes so they must be replaced by multiple model runs.) Repeat steps 1 through 3 for all mix-driven capacityconstraining tool groups. purchased to keep capacity loading from exceeding 85%. 5. Repeat steps 2 through 4 for all tool groups that are mix-driven capacity constraints. Step 5. Quantifying and Prioritizing Mix-Driven Capacity Constraints In order to quantify the risk of under-investment in capacity, Headway put...
View Full Document
- Spring '11
- Semiconductor device fabrication, Headway, tool group