Title :
Phi-scatterometry for integrated linewidth and process control in DRAM manufacturing
Author :
Hettwer, Andrea ; Benesch, Norbert ; Schneider, Claus ; Pfitzner, Lothar ; Ryssel, Heiner
Author_Institution :
Fraunhofer Inst. of Integrated Circuits, Erlangen, Germany
fDate :
11/1/2002 12:00:00 AM
Abstract :
A cost-effective scatterometry method is presented that is suited for integrated pattern and process control and is valuable as a supplement to conventional scanning electron microscopes. The phi-scatterometry procedure is carried out directly on periodic functional patterns instead of using additional test structures. Time-consuming simulations of diffraction effects are not required. The measurement results are evaluated by neural networks performing classifications of pattern and process parameters. Thereby, fast fault detection and immediate process control are achieved. The measurements were performed on a 300-mm wafer with systematically varied focus and exposure as well as on production lots, both with DRAM patterns featuring trenches in two dimensions. A phi-scatterometry prototype was built which is suited for flexible mobile metrology in 300-mm production environments.
Keywords :
DRAM chips; light scattering; lithography; neural nets; periodic structures; process control; shape control; 300 mm; DRAM manufacturing; DRAM patterns; fault detection; flexible mobile metrology; integrated linewidth/process control; neural networks; periodic functional patterns; phi-scatterometry; production environments; systematically varied focus; trenches; Diffraction; Manufacturing processes; Neural networks; Performance evaluation; Periodic structures; Process control; Radar measurements; Random access memory; Scanning electron microscopy; Testing;
Journal_Title :
Semiconductor Manufacturing, IEEE Transactions on
DOI :
10.1109/TSM.2002.804907