Electroless copper deposition by non-isothermal deposition technology

In conventional electroless plating of copper, high deposition rate and good bath stability are not easily achieved simultaneously. Some trade-offs must be made. In this study, we provide a novel process called non-isothermal deposition (NITD) method to deposit electroless copper. Our results show this method do provide a promising high deposition rate and the bath life is significantly extended by effectively prohibiting the occurrence of the Cannizzaro reaction within the solution. By this method, the electroless copper can be plated at a temperature as high as 120 °C and its deposition rate can be three-fold higher than that gained with the conventional isothermal method. Moreover, a smooth film with the preferred (1 1 1) copper crystal plane can be achieved directly by using NITD system without further annealing treatment. It is good for electromigration consideration and it will be effective in lowering the resistivity of the copper deposit.