The effect of plasma pretreatment on the Si/Si bonding behaviour

The effect of plasma treatments on Si/ Si wafer bonding was investigated. Etching in SF6 caused a bonding behaviour generally known from hydrophobic (HF etched) samples, whereas adding O2 to the feed gas caused the Si(100) surfaces to become hydrophilic and spontaneous bonding was achieved. Plasma treatments than for hydrophilic bonded wafer pairs already after annealing at T >=400 deg C. Very strong bonds, however, are even obtained by lower temperature annealing (T <= 400 deg C) after plasma treatments in O2.