Singulation of Electronic Packages With Abrasive Waterjets

Abrasive waterjets (AWJ) were used for the first time to commercially singulate electronic chips such as those used for flash memory cards found in digital cameras, cell phones, and universal serial bus (USB) storage devices. Cutting these components requires high cutting speed, high edge quality, accuracy, and precision. For example, a minimal accuracy needed is $∼0.1mm$ and a minimum $Cpk$ of 1.33. A relatively small AWJ $(∼0.38mm)$ was successfully used to accurately cut chips at speeds of $20-60mm∕s$⁠. It was determined that the use of machine vision is critical to meeting the accuracy requirements. The cutting process consisted of piercing starting holes and then cutting shaped pattern cuts to contour the chip components. Drilling holes was performed without delamination, and the cutting speed was optimized to meet the intricate chip geometry. Because of the relatively high volume of components to be cut, requiring around-the-clock duty, process and machine reliability are of critical importance. This paper discusses the results and observation of the cutting process as well as the performance of the system.