Authors: Reza Asgari and Rajiv Roy Company: Rudolph Technologies, Inc. Date Published: 11/11/2014
IWLPC (Wafer-Level Packaging)
Abstract: Wafer dicing has become a pacing item at advanced nodes for both wafers that will undergo additional packaging steps as well as Wafer-level Chip-scale Package (WLCSP). Due to highly porous nature of low-k material and thinned wafers, the saw process is prone to chipping and delamination. Today, the preferred approach is a combination of laser grooving followed by saw. The shape and direction of laser grooving impact the saw. Traditional inspection and metrology of post-saw inspection focused on go / no-go decisions. Inspection and metrology are now focusing on process control to better characterize the different topography during laser groove. This paper will discuss the various metrology requirements and data from test wafers. Real-time monitoring of process tools can help identify potential problems to prevent further loss. A future direction being proposed is to feed-forward the metrology information from laser-grooving to the saw process to minimize chipping and delamination.
Post-saw Inspection, laser groove metrology, chipping, delamination, Kerf Inspection, Process Control