A test structure for monitoring micro-loading effect of MOSFET gate length

The etch rate is strongly sensitive to the pattern density on the wafer surface:micro-loading effect. Etch rate data should therefore be obtained from monitoring wafers with a pattern density similar to that of product wafers. This paper presents the test structures which easily incorporate the micro-loading effect of a MOSFET gate length into electrical measurement. Experimental results and analysis shows that the micro-loading effect of gate length depends solely on etch rate problem rather than photolithographic issues.