Patent ID: 9548202
Date: 2017-01-17
CPC Classifications: B32B,H01L

Claim:
1. A method of bonding by molecular adhesion, comprising: positioning a first wafer and a second wafer within a hermetically sealed vessel in an environment comprising a concentration of water in gaseous form; adsorbing water molecules on surfaces of the first wafer and the second wafer; evacuation of the vessel to a first pressure between 1 hPa and 400 hPa and desorbing some of the water molecules present in the form of condensation on the surfaces of the first wafer and the second wafer, and optimizing the desorption so as to obtain a concentration of water in the environment lower than 10,000 ppm while allowing for subsequent bonding of the surfaces of the first wafer and the second wafer by hydrophilic molecular adhesion; adjustment of the pressure in the vessel to a second pressure higher than the first pressure by introduction of a dry gas, the dry gas having a concentration of water lower than 10,000 ppm; and bringing the first and second wafers into contact while a residual amount of water molecules remain present on the surfaces of the first wafer and the second wafer, followed by the initiation of the propagation of a bonding wave between the two wafers resulting in the hydrophilic molecular adhesion between the first wafer and the second wafer, while maintaining the vessel at the second pressure.