Surface activated bonding of ALD Al2O3 films

Abstract

Abstract Room temperature direct bonding of plasma enhanced ALD Al2O3 films was achieved by using surface activated bonding. ALD Al2O3 films were amorphous with C and O impurities contained. The high deposition power and H2 plasma post-treatment increased the crystallinity and hydrophilicity of ALD Al2O3 films, respectively. However, both methods increased the surface roughness of films slightly. The bond strength of ALD Al2O3 films was not changed obviously by raising the deposition power, but it experienced a slight decrease after H2 plasma post-treatment. The water in the debonding atmosphere influenced the bond strength of standard ALD Al2O3 films greatly, which was 0.54 J m−2 in humid air and 1.00 J m−2 in anhydrous N2. The bond strength in vacuum was just a little larger than that in anhydrous N2 suggesting that the trapped water at the bonding interface was less.