Patent ID: 6114226
Filing Date: 2000-09-05
Classification: H01L

Abstract:
A method of manufacturing an electrostatic discharge protective circuit with an internal circuit on a substrate, the substrate having a protective region and a device region, and the protective region and the device region comprises a first metal-oxide semiconductor (MOS) transistor and a second MOS transistor, respectively, wherein the first MOS transistor includes a first electrode, a spacer on a sidewall of the gate electrode, and a source/drain region in the substrate at each side of the gate electrode, the source/drain region with dopants of a first conductive type having a lightly doped drain region beneath the spacer, the method comprising the steps of:forming a salicide layer on the source/drain region and the gate electrode of the first MOS transistor, wherein a device's salicide layer at the device region may also be formed on an exposed surface of the second MOS transistor containing silicon;forming a patterned photoresist layer to cover a portion of the salicide layer about at the central region at each side of the gate electrode, whereby a portion of the salicide other than the central region is exposed;removing the exposed portion of the salicide layer to expose a portion of the source/drain region, using a mask comprising the patterned photoresist layer, the spacer, and the gate electrode, wherein a remaining portion of the salicide layer still covers the source/drain region about at the central region;implanting dopants of a second conductive type into the substrate beneath the source/drain region to form a second-conductive-type doped region, using a mask comprising the patterned photoresist layer, the spacer, and the gate electrode, whereby the second-conductive-type doped region and the source/drain region form a diode;removing the spacer on the sidewall of the gate electrode to expose the lightly doped drain region; anddoping the lightly doped drain region to be a heavily doped region, so as the merge the lightly doped drain region into the source/drain region.