Wafer bonding device and wafer bonding method

A wafer bonding method comprising:

• holding a first substrate with a holding mechanism by applying a voltage to said holding mechanism, said holding mechanism being arranged on an upper side of an inside of a chamber;
• holding a second substrate with another holding mechanism, said another holding mechanism being arranged on a lower side of said inside of said chamber;
• generating a bonded substrate by bonding said first substrate and said second substrate;
• dechucking said bonded substrate from said holding mechanism after a voltage which attenuates while alternating is applied to said holding mechanism;
• raising said holding mechanism;
• and
• supplying gas between said bonded substrate and said holding mechanism such that the bonded substrate held by said raised holding mechanism falls on said another holding mechanism;
• wherein said gas is supplied between said bonded substrate and said raised holding mechanism when said bonded substrate is not dechucked from said holding mechanism and said bonded substrate is not in contact with another holding mechanism,
• wherein said gas is not supplied between said bonded substrate and said raised holding mechanism when said bonded substrate is dechucked from said holding mechanism.