| Popis: |
A tiny footprint electrically probable single layer defocus monitor/test structure has been designed and tested to show sub-10nm resolution in electrical or electronic defocus monitoring. Electronic testing is a low-cost must have for on-chip production process monitoring which will become necessary for effective Design for Manufacturing. This programmable defocus monitor can be designed to pinch open at various levels of defocus by modifying four different layout parameters, CD, probe size, offset, and the number of rings. An array of these structures can be read as a series of opens and shorts, or 1s and 0s, to electronically extract defocus. One important feature of this defocus test structure is that it has an asymmetric response through focus, which translates to a high sensitivity to defocus at low defocus values or close to nominal conditions. Simulation and experimental results have shown good sensitivity for both on axis, tophat, and offaxis, quasar, illumination. This paper will present both simulation and experimental results that demonstrate the programmability and sensitivity of this test structure to defocus. |
