Abstract
Today, copper pillar bumping now in high volume production for mobile electronics is also a transformative technology for next generation flip chip [1] interconnects which offers advantages in many designs while meeting current and future requirements. With the continuous shrinking dimensions of semiconductor devices, the package’s design and size are approaching the dimensions of the singulated die. Moreover, failure analysis involving copper pillar packages would be the major challenges faced by analysts as copper pillar devices in nature hides its solder joints beneath its die causing obstruction in quality inspection as well as judging its solder joint strength. Chemical wet etch or deprocessing [2] by using potassium hydroxide (KOH) to remove all silicon die have disadvantages of over etching on silicon substrate and tin (Sn) surrounding the Cu pillar. Therefore, quality of sample preparation is critical and new methodology is needed.
