Abstract:
Process device scaling continues through the use and deployment of novel manufacturing methods and integration schemes. Without lithography scaling, schemes include the use of multiple processing for pitch splitting to reduce critical dimensions, among other methods are now widely used and expected to be deployed through 5nm technology. The number of process steps utilized in these processes increases significantly, but when deployed effectively, can enable scaled devices with viable manufacturing yields. These processes have numerous tolerances that continue to compound. Critical dimension variability will significantly impact the final device dimensions and represent an ever larger fraction of the device as structures scale beyond 10nm. In recent years, process control metrology has enabled significant advances in complex profile control for all of these crucial processing steps. Improvements in computational microscopy, including the use of Optical Critical Dimension (OCD) metrology has now become common place in modern fabs. OCD techniques have fundamentally no lower bound in resolution or precision. The ability to measure on the appropriate structure at the appropriate step in line with a reasonable cost and capability significantly contribute to the timely development and manufacturing ramp of these advanced device nodes. We will provide an overview of tolerance stacking at 10nm and the improvements in system capability to enable cost effective factory control at 5nm and future nodes. The process is brought to a virtuous circle, as the technology being developed by the leading device manufactures enables ultimately better computation for better process control, keeping technology scaling on pace.