Process and device for bonding wafers

Process for bonding at least two substrates (1, 2) with a device having a lower pressure plate (5) for holding the substrates (1, 2) and transferring pressure and heat to the substrates (1, 2), an upper pressure plate (6) located opposite the lower pressure plate (5) for transferring pressure and heat to the substrates (1, 2), heating means (7, 8) for heating up the substrates (1, 2) to temperatures above 100° C., and pressure charging means for charging the lower (5) and/or upper pressure plate (6) with a pressing force F higher than 500 N, the upper pressure plate (6) and/or the lower pressure plate (5) being substantially free from the chemical elements Ti and Mo at least on one substrate contact surface (5o, 6o) facing the substrates, said process comprising the following process steps:

• a) introduction of the substrates (1, 2) between an upper pressure plate (6) and a lower pressure plate (5),
• b) charging of the substrates (1, 2) with pressure by means of a pressure charging means, in particular an actuator (9), with a pressing force F, in particular higher than 500 N, preferably higher than 1,000 N, and
• c) charging of the substrates (1, 2) with heat by means of a heating means (7, 8), in particular to temperatures above 100° C., preferably above 250° C.