Texas Instruments Incorporated
Electrical test structure and method for monitoring deep trench impedance to substrate

Abstract:

A microelectronic device includes a deep trench test structure in semiconductor material of a substrate. The deep trench test structure has pad trench segments with a liner of electrically non-conductive material and a trench fill material on the liner, extending to tops of the pad trench segments. The pad trench segments extend across a probe pad region; at least 20 microns in every lateral direction. The trench fill material at the top of the pad trench segments occupies at least 25 percent of the probe pad region. The liner may electrically isolate the trench fill material from the semiconductor material, or the deep trench test structure may include a contact trench segment wherein the trench fill material contacts the semiconductor material. The deep trench test structure may be probed on the pad trench segments to measure an impedance between the trench fill material and the semiconductor material.