Qualification of Microchip Al Bondpad and Elimination of NSOP

In wafer fab and assembly processes, non-stick on pad (NSOP) problem impacts seriously yields of the products as the electrical communication between the integrated circuit (IC) chips and other components taking place via the bondpad of the chip. NSOP (Non-Stick On pad) is a failure mode of the IC chip that occurs as a result of poor adhesion between the Aluminium (A1) bondpad and either the bond wire or solder contact. Such failures can be observed even for nanoscale chips such as the 65nm, 45nm, 40nm, and 28nm nodes and beyond. In order to eliminate NSOP problem to enhance the yield of products, process engineers from wafer fab and assembly house together with failure analysis engineers have to know what a good quality bondpad is and how to evaluate and qualify. On these common questions and concerns, in this paper, we will study and introduce Al bondpad qualification methodologies (OSAT and OSSD) and eliminate NSOP problem.