Patent ID: 9702894
Date: 2017-07-11
CPC Classifications: G01P

Claim:
1. A monolithic z-axis torsional CMOS MEMS accelerometer, made of a complementary metal-oxide semiconductor (CMOS) with a micromachining process, and comprising: a matching frame comprising a first side zone, a second side zone, a third side zone, and a fourth side zone which adjoin successively in an enclosing manner, wherein the first side zone and the third side zone are opposite each other, whereas the second side zone and the fourth side zone are opposite each other, wherein the fourth side zone and the first side zone adjoin each other; two anchors disposed and located at a midpoint of the first side zone and the midpoint of the third side zone, respectively; a first comb structure adjoining the second side zone, a second side zone-adjoining portion of the first side zone, and a second side zone-adjoining portion of the third side zone, and the first comb structure having a plurality of sensing units arranged side by side; a second comb structure adjoining the fourth side zone, a fourth side zone-adjoining portion of the first side zone, and a fourth side zone-adjoining portion of the third side zone, and the second comb structure having a plurality of sensing units arranged side by side; and a proof mass disposed between the first comb structure and the second comb structure inside the matching frame to adjoin the first comb structure and the second comb structure, wherein an axis of the proof mass is defined by a virtual line which connects the two anchors, and two disconnected regions which are symmetrical to each other but do not adjoin the proof mass are disposed between the axis and the first comb structure; wherein the sensing units each include a first fixed single unit, a mobile single unit, and a second fixed single unit which are arranged successively but not connected; each said first fixed single unit and each said second fixed single unit of the first comb structure adjoin the second side zone; each said first fixed single unit and each said second fixed single unit of the second comb structure adjoin the fourth side zone; each said mobile single unit adjoins the proof mass; wherein the first fixed single units each have a first upper portion and a first lower portion which are separated by a silicon dioxide unit; wherein the second fixed single units each have a second upper portion and a second lower portion which are separated by the silicon dioxide unit.