Electrochemical deposition of indium from chloride bath for low-temperature microbump bonding

Abstract

Indium chloride bath was characterized towards the application of low-temperature thermal compression bonding. The electrochemical behavior of the indium chloride bath was analyzed using the cyclic voltammetry method. Electrochemical deposition of indium was carried out at various deposition factors on different materials such as copper, nickel, and cobalt. Based on the results of indium deposition obtained from the blanket films, indium bumps were electrochemically fabricated inside a through-resist hole pattern at various current densities. In addition, stacked indium bumps with various metals (Cu/In, Cu/Ni/In, Cu/Co/In) were formed for a practical application of micro bump bonding. Moreover, the formation of the intermetallic compounds between indium and under bump metallization was investigated.