Wafer Level Chip Scale Package (WLCSP) technology is used because it produces low cost, small footprint packages to be directly mounted into smartphones, tablet PC's and other mobile devices, as well as, automotive applications. The manufacture of these mobile devices and automotive applications are demanding lower defect parts per million (DPPM) from their suppliers of WLCSP devices.
Today, the backend process flow for mobile WLCSP devices is a single insertion test at wafer probe. With this flow, there is no test that is done after device singulation (wafer saw). The reason for this flow is that there has been no cost effective way to handle singulated WLCSP devices in high volume manufacturing environment.
This presentation explores key attributes and technical challenges in testing singulated WLCSP devices and it provides insight as to how those technical challenges will get addressed. A practical approach is to hold hundreds of singulated devices in an array looking similar in format to a device strip. By placing the singulated devices such an array, a device handler can then be used to provide true Final Tri-temp Test of WLCSP devices.
Ultimately the final test of WLCSP devices must address the shortcomings of today's probe test flow.