Here is the abstract you requested from the imaps_2019 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Optimizing the Within Wafer Non-Uniformity at the Chemical Mechanical Planarization step in Interposers and RDL fabrication process for 3D IC stacking|
|Keywords: Chemical Mechanical Planarization, Copper RDL, Within Wafer Non Uniformity|
|Chemical Mechanical Planarization (CMP) is an integral step in fabrication processes of through silicon via based Interposer and Redistribution layer for Routing. At the CMP step our objective is to remove the overburden with minimum recess and dishing. In this work we evaluated and optimized the within wafer non-uniformity (WIWNU). It was observed that the conventional reference to WIWNU during CMP have been ignoring one of the key wafer parameter and a better understanding is needed to enhance post CMP uniformity across the wafer. We use 200 mm blank electroplated Copper wafers to optimize the uniformity of removal rate with respect to polishing parameters, such as slurry flow, slurry composition, down force, relative velocity of wafer surface with pad, etc. Following this we will discuss the WIWNU in a product wafer with various pattern density. The results on blank wafer is primarily electroplated Copper based, however for the patterned wafer we compare results from both Copper and Tungsten based metal routings.|
|Amit Kumar, Associate Director