US 12,248,019 B2
Diode test module for monitoring leakage current and its method thereof
Chih-Ting Yeh, Hsinchu County (TW); Sung Chih Huang, Yilan County (TW); Kun-Hsien Lin, Hsinchu (TW); and Che-Hao Chuang, Hsinchu County (TW)
Assigned to AMAZING MICROELECTRONIC CORP., New Taipei (TW)
Filed by AMAZING MICROELECTRONIC CORP., New Taipei (TW)
Filed on Nov. 29, 2021, as Appl. No. 17/536,513.
Prior Publication US 2023/0168298 A1, Jun. 1, 2023
Int. Cl. H01L 27/02 (2006.01); G01R 31/26 (2020.01); G01R 31/30 (2006.01)
CPC G01R 31/3008 (2013.01) [G01R 31/2632 (2013.01); H01L 27/0255 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method applicable to a diode test module for monitoring leakage current, comprising:
providing a substrate having a first conductivity type, and an epitaxial layer having a second conductivity type on the substrate;
forming a well region having the first conductivity type in the epitaxial layer, and a first heavily doped region having the second conductivity type and a second heavily doped region having the second conductivity type in the well region, wherein the first heavily doped region and the second heavily doped region are electrically connected with a first I/O terminal and a second I/O terminal, respectively;
forming at least one isolation trench between the first heavily doped region and the second heavily doped region for electrical isolation, wherein the at least one isolation trench has a depth greater than that of the epitaxial layer;
providing a monitor cell which is configured in a current conduction path between the first I/O terminal and the second I/O terminal when either the first I/O terminal or the second I/O terminal is biased, wherein the monitor cell comprises a third heavily doped region having the second conductivity type and a fourth heavily doped region having the second conductivity type, the at least one isolation trench is configured between the third heavily doped region and the fourth heavily doped region for electrical isolation, and the third heavily doped region and the fourth heavily doped region are metal wired; and
when an operation voltage is input through the first I/O terminal or the second I/O terminal, it is determined if the first heavily doped region or the second heavily doped region is truly fabricated in the well region by measuring whether a leakage current is generated through the monitor cell.