A method for processing product wafers using carrier substrates is disclosed. The method includes a step of bonding a first carrier wafer to a first product wafer using a first temporary adhesion layer between a first carrier wafer surface and a first product wafer first surface. Another step includes bonding a second carrier wafer to a second product wafer using a second temporary adhesion layer between a second carrier wafer surface and a second product wafer surface. Another step includes bonding the first product wafer to the second product wafer using a permanent bond between a first product wafer second surface and a second product wafer first surface. In exemplary embodiments, at least one processing step is performed on the first product wafer after the first temporary carrier wafer is bonded to the first product wafer before the second product wafer is permanently bonded to the first product wafer.