Patent attributes
A device source wafer includes a wafer substrate, devices formed on or in the wafer substrate at a location on the wafer substrate, and test structures disposed on the wafer substrate connected to some but not all of the devices. The devices include a first device disposed at a first location and a second device disposed at a second different location on the wafer substrate. The test structures include at least a first test structure connected to the first device and a second test structure connected to the second device. The first test structure is adapted to measuring a characteristic of the first device and the second test structure is adapted to measuring the characteristic of the second device. An estimated characteristic of unmeasured devices is derived from the first and second device locations and measured characteristics and the device is selected based on the estimated characteristic.