Patent ID: 9671215
Date: 2017-06-06
CPC Classifications: G01B,H01L

Claim:
1. Wafer to wafer alignment comprising: a first semiconductor wafer having a plurality of semiconductor chips and kerf areas surrounding each of the semiconductor chips and a second semiconductor wafer having a plurality of semiconductor chips and kerf areas surrounding each of the semiconductor chips; the first semiconductor wafer having a plurality of selectively-activated first alignment arrays for aligning the first semiconductor wafer with the second semiconductor wafer, each of the first alignment arrays comprising a difference engine and at least one alignment structure comprising at least one antenna connected to a semiconductor device on the first semiconductor wafer, the at least one antenna in each of the first alignment arrays being selectively activated to act as a charge source or as a charge sensing receptor, the first alignment arrays being located in the kerf areas of the first semiconductor wafer; the second semiconductor wafer having a plurality of selectively activated second alignment arrays for aligning the first semiconductor wafer with the second semiconductor wafer, each of the second alignment arrays comprising a difference engine and at least one alignment structure comprising at least one antenna connected to a semiconductor device on the second semiconductor wafer, the at least one antenna in each of the second alignment arrays being selectively activated to act as a charge source or as a charge sensing receptor, the second alignment arrays being located in the kerf areas of the second semiconductor wafer; and wherein in operation the antenna in the at least one alignment structure in each of the first alignment arrays being activated as the charge sensing receptor to form a plurality of charge sensing receptors and the antenna in the at least one alignment structure in the second alignment arrays being activated as the charge source to form a plurality of charge sources, the first semiconductor wafer and the second semiconductor wafer being moved relative to one another until the plurality of source charges sensed by the plurality of charge sensing receptors and processed by the difference engine in each of the first alignment arrays are substantially equal at each of the plurality of charge sensing receptors.