Patent ID: 6788598
Filing Date: 2004-09-07
Classification: G11C,H01L

Abstract:
A test key for detecting overlap of an active area and a deep trench capacitor on a dynamic random access memory cell, wherein the test key is disposed on a scribe line of a substrate, the test key comprising:two parallel active areas disposed on the substrate; two parallel first deep trench capacitors disposed on the substrate along the outer side of the two active areas respectively, wherein the first deep trench capacitors are shorter than the active areas; a rectangular active word line disposed on the substrate, covering the two first deep trench capacitors and partially covering the two active areas of equal length to the first deep trench capacitors; a first passing word line perpendicular to the active areas, disposed on and parallel to a first side of the rectangular active word line and approximately crossing the two parallel active areas; a second passing word line perpendicular to the active areas, disposed parallely outside the first passing word line and crossing in a substantially perpendicular fashion a first end of the two parallel active areas; a third passing word line perpendicular to the active areas, disposed on and parallel to a second side of the rectangular active word line and crossing in a substantially perpendicular fashion a second end of the two parallel active areas; two second deep trench capacitors disposed under where the two first passing word lines overlap the two active areas respectively; and four contacts disposed on the two first active areas located between the first and second word lines and between the third and the rectangular active word line.