In some embodiments, the present disclosure relates to a method for bonding a first wafer to a second wafer. The method includes aligning a first wafer with a second wafer, so the first and second wafers are vertically stacked and have substantially planar profiles extending laterally in parallel. The method further includes bringing the first and second wafers into direct contact with each other at an inter-wafer interface. The bringing of the first and second wafers into direct contact includes deforming the first wafer so that the first wafer has a curved profile and that the inter-wafer interface is localized to a center of the first wafer. The second wafer maintains its substantially planar profile throughout the deforming of the first wafer. The method further includes deforming the first wafer and/or the second wafer to gradually expand the inter-wafer interface from the center to an edge of the first wafer.