Patent ID: 9484338
Filing Date: 2016-11-01
CPC Classification: H01L,H02H

Claim Text:
1. A diode string having a plurality of diodes for ElectroStatic Discharge (ESD) protection of a CMOS IC device, comprising: a first diode and a last diode in the diode string, wherein the first diode and the last diode are both formed on a bottom layer in a silicon substrate, and wherein the first diode and the last diode are separated with a first shallow trench isolation (STI) region in the bottom layer; a plurality of remaining diodes in the diode string, wherein the remaining diodes are all formed on at least one upper layer above the bottom layer, wherein the plurality of the remaining diodes on the upper layer are structurally isolated from the first diode and the last diode on the bottom layer, and wherein any two adjacent diodes of the remaining diodes in the at least one upper layer are separated from each other with at least a second STI region in the upper layer; and a plurality of conductive lines that connect the first diode and the last diode on the bottom layer sequentially with the remaining diodes on the at least one upper layer to form a three dimensional (3D) structure of the diode string.