Surface activated bonding of ALD Al2O3 films

Abstract Room temperature direct bonding of plasma enhanced ALD Al 2 O 3 films was achieved by using surface activated bonding. ALD Al 2 O 3 films were amorphous with C and O impurities contained. The high deposition power and H 2 plasma post-treatment increased the crystallinity and hydrophilicity of ALD Al 2 O 3 films, respectively. However, both methods increased the surface roughness of films slightly. The bond strength of ALD Al 2 O 3 films was not changed obviously by raising the deposition power, but it experienced a slight decrease after H 2 plasma post-treatment. The water in the debonding atmosphere influenced the bond strength of standard ALD Al 2 O 3 films greatly, which was 0.54 J m −2 in humid air and 1.00 J m −2 in anhydrous N 2 . The bond strength in vacuum was just a little larger than that in anhydrous N 2 suggesting that the trapped water at the bonding interface was less.