| 摘要 |
The present invention is related to a method for bonding a first semiconductor substrate to a second semiconductor substrate by direct bonding, wherein the substrates are both provided on their contact surfaces with a dielectric layer, followed by a CMP step for reducing the roughness of the dielectric layer. Preferably, the dielectric layer after CMP has an roughness of less than 0.2nm RMS. Then a layer of SiCN is deposited onto the dielectric layer, followed by a CMP step which reduces the roughness of the SiCN layer to the order of 1 tenth of a nanometre. Preferably the RMS value after CMP is less than 0.1nm. Then the substrates are subjected to a pre-bond annealing step. The substrates are then bonded by direct bonding, possibly preceded by one or more pre-treatments of the contact surfaces, and followed by a post-bond annealing step, at a temperature of less than or equal to 250°C, preferably between 200°C and 250°C. It has been found that the bond strength is excellent, even at the above named annealing temperatures, which are lower than presently known in the art. |
