Test key and method for validating the position of a word line overlaying a trench capacitor in DRAMs

摘要

A test key for validating the position of a word line structure overlaying a deep trench capacitor of a DRAM. The test key is deposited in the scribe line region of a wafer. The deep trench capacitor is deposited in the scribe line region and has a buried plate. A rectangular word line is deposited in the scribe line and covers a portion of the deep trench capacitor, and two passing word lines are deposited above the deep trench. A first doping region and a second doping region are deposited between the rectangular word line and the first passing word line and between the rectangular word line and the second passing word line respectively. A first plug, a second plug and a third plugs are coupled to the first doping region, the second doping region and the buried plate respectively.