Before revision: In order to verify the robustness of an integrated circuit design, semiconductor manufacturers will fabricate corner lots, which are groups of wafers that have had process parameters adjusted according to these extremes, and will then test the devices made from these special wafers at varying increments of environmental conditions, such as voltage, clock frequency, and temperature, applied in combination (two or sometimes all three together) in a process called characterization.
After revision: To verify the robustness of an integrated circuit design, semiconductor manufacturers will fabricate corner lots, which are groups of wafers that have had process parameters adjusted according to these extremes, and will then test the devices made from these special wafers at varying increments of environmental conditions, such as voltage, clock frequency, and temperature, applied in combination (two or sometimes all three together) in a process called characterization.