The challenges in automotive Low-k fine pitch bonding

Abstract

Gold ball bonding remains to be the key technology in the assembly of semiconductor packaging. In response to the demand for higher I/O's and increased package functionality, the bond pad pitch (BPP) and bond pad opening (BPO) will subsequently decrease. This technology trend demands the use of finer wire diameters and provide good wire bonding process. However, wire bond reliability continues to be the most challenging area with ever finer pitch devices, particularly to meet automotive requirement. Non-stick on pad (NSOP) and insufficient intermetallic coverage (IMC) due to either wafer surface contaminants, wire bond process and material set are still the main issue in Low-K wire bonding technology. Decapsulation and wire pull after temperature cycling is another challenge that needs in depth focus. This paper specifically discusses various phenomenons of bondability, wafer variation and reliability issue towards meeting the automotive reliability requirements. Failure analysis results are also briefly discussed.