DEVELOPMENT OF PROCESS VARIATION TOLERANT STANDARD CELLS
Priyanka Thakore · OhioLink ETD Center (Ohio Library and Information Network) · 2007
ASIC design using standard cell library cells is the most widespread design method.Lower process technologies drive a need to incorporate Design for Manufacturability technique early in the design flow.In the thesis, this is achieved by developing variation tolerant standard cell library embedded in the current design flow.This design technique can help cut down the time penalty due to re-spin and incorporates DFM at the pre-layout stage.We present a framework to develop the process variation-tolerant standard cell library and implement them in creating robust designs.In this work, we build performance macro models based on the relative variation in the various parameters like width, oxide thickness, threshold voltage etc., for each transistor in the standard cell.A novel approach is taken to model these parameter variations and the standard cells are optimized for intrinsic delay, power and area using reduced dimension response surface technique.A DFM (Design for Manufacturability) Library is developed with the various views needed for integration with the standard VLSI Design flow.This method is analyzed by subjecting designs, which are synthesized with un-optimized and the DFM library Cells, to parameter variations.Results show an improvement in the critical path slack in the order of 314% (3X) for the largest benchmark circuit and average of 15% for the small and medium sized circuits in presence of variation.This thesis work lays the foundation for achieving reliable parametric variation tolerant designs rendering significant changes to the current design flow.To my lovely Mother.My first and foremost thanks to the almighty for his blessings at every stage of my life.I would like to express my sincere thanks to Dr. Ranga Vemuri for his valuable ideas and motivation throughout my research work.He has been a fantastic teacher and a guide to me.Working with him has been a great learning experience