Patent ID: 11955454
Assignee: YANGTZE MEMORY TECHNOLOGIES CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. A wafer bonding method, comprising:
determining a relative position between a first alignment mark on a first wafer and a second alignment mark on a second wafer, by using an optical beam;
performing a first alignment by adjusting the relative position by moving the first wafer or the second wafer in a horizontal plane parallel to a surface of the first wafer or a surface of the second wafer based on the relative position;
adjusting, with the optical beam being turned off, a distance between the first wafer and the second wafer by moving the first wafer or the second wafer in a vertical direction perpendicular to the horizontal plane;
determining an updated relative position between the first alignment mark on the first wafer and the second alignment mark on the second wafer, by turning on the optical beam;
performing a second alignment by adjusting the updated relative position by moving the first wafer or the second wafer in a horizontal plane; and
bonding the first wafer to the second wafer.