Method for bonding two hydrophilic surfaces

A method of direct bonding of two substrates comprising the following steps:

• supplying a first substrate and a second substrate, the first substrate being covered by a first hydrophilic surface and the second substrate being covered by a second hydrophilic surface,
• deposition of a specific molecule on the first hydrophilic surface or on the second hydrophilic surface, the specific molecule comprising a hydrophilic functional group and a basic functional group, separated by at least one atom, wherein the specific molecule is deposited in an amount configured to improve the bonding between the first hydrophilic surface and the second hydrophilic surface;
• and
• contacting the first hydrophilic surface with the second hydrophilic surface, on at least one of which the specific molecule is deposited, whereby the two hydrophilic surfaces are bonded one with the other, the specific molecule being disposed between the two hydrophilic surfaces at the amount configured to improve the bonding, and the first substrate and the second substrate are assembled with improved bonding via the specific molecule.