Enabling Device Scaling through Thin Film Stress Control
The demand for more powerful, more efficient memory devices continues to introduce a need for innovative materials and processing steps. As the scaling of these devices continues to shrink the aspect ratios increase accordingly, creating challenges in the mechanical properties of the device films. Stress in the thin film layers of the devices can lead to high device failure, and lower overall device yield. In addition, high modulus, high stress films used for patterning can create stress and bow on the wafer leading to difficulties in wafer handling as well as photo-registration errors. These challenges have led to an increased need for film stress control without sacrificing film quality required for performance.
Motivated by the need for improved stress control, Lam Research has developed several products designed to meet these needs such as the Vector Datum backside deposition tool that allows for both local and global control of wafer bow. In addition, novel films have been introduced to provide stress control and mechanical stability of high aspect ratio features.