High-strength bonding of semiconductors, metals, and dielectrics can be obtained even at room temperature.
[1][2] In the standard SAB method, wafer surfaces are activated by argon fast atom bombardment in ultra-high vacuum (UHV) of 10−4–10−7 Pa.
The bombardment removes adsorbed contaminants and native oxides on the surfaces.
The activated surfaces are atomically clean and reactive for formation of direct bonds between wafers when they are brought into contact even at room temperature.
The modified SAB was developed to solve this problem, by using a sputtering deposited Si intermediate layer to improve the bond strength.