Patent ID: 7390723

Claim:
A method for stacking and bonding wafers in precision alignment by detecting alignment marks provided on wafer edges, comprising the steps of: (a) providing at least a first wafer having at least a first pattern and at least a second pattern disposed on the cross-section thereof, at least a second wafer having at least a third pattern and at least a fourth pattern disposed on the cross-section thereof, and at least a sensing device, while pairing the first pattern with the third pattern and pairing the second pattern with the fourth pattern; (b) actuating the first wafer and the second wafer for enabling the first wafer to parallel the second wafer and to be a distance apart from the second wafer; and (c) actuating the first wafer and the second wafer for bringing the two wafers to move toward each other while enabling the sensing device to detect and determine whether or not the first pattern is in a position capable of matching with the third pattern and the second pattern in another position capable of matching with the fourth pattern, wherein the sensing device is a coupled charged device, the sensing device being utilized to detect the alignment patterns provided on wafer edges.