Semiconductor integrated circuit device with protection capability for protection circuits from static electrical charge
View Patent ↗Semiconductor Integrated Circuit (IC) devices such as diode and MOSFET that protect circuits from Electrostatic Discharge (ESD) are formed. A diode is formed by an N+ (or P+) and P+ (or N+) diffusion layers within an N (or P) well on a P (or N) type semiconductor substrate. The N+ (or P+) diffusion layer of the diode is connected to the power supply. Additionally, an NMOSFET (or PMOSFET) is formed with N+ (or P+) source/drain regions and a gate on the same P (or N) type substrate. The P+ (or N+) diffusion layer of the diode and the N+ (or P+) source/drain regions of the NMOSFET (or PMOSFET) are connected to a fuse through second and first levels of metal wirings.
1. A semiconductor integrated circuit device comprising:
a semiconductor substrate of one conduction type;
circuits formed on said substrate;
power supply wiring connected to said circuit;
a fuse connected to said circuit; and
a protection circuit protects said circuit, wherein said protection circuit comprising;
a first diffusion layer of an opposite conduction type formed on said substrate,
a well layer of the opposite conduction type formed in said substrate,
a second diffusion layer of the conduction type formed in said well layer,
a third diffusion layer of the opposite conduction type formed in said well layer,
said third diffusion layer being connected to said power supply wiring and forming a diode with said second diffusion layer; and
wiring connected to said first diffusion layer, said second diffusion layer, and said fuse.
2. The semiconductor integrated circuit device according to claim 1 , wherein:
said circuit includes a field-effect transistor; and
said first diffusion layer is a source or drain of said field-effect transistor.
3. The semiconductor integrated circuit device according to claim 1 , wherein:
there is a plurality of each of said fuses, said first diffusion layers, said second diffusion layers, said third diffusion layers, and said wiring;
each first diffusion layer corresponds to any of said plurality of fuses;
each second diffusion layer is formed in said well layer that corresponds to any of said plurality of fuses;
each third diffusion layer is formed in said well layer that corresponds to any of said plurality of second diffusion layers, and further, forms a diode with said corresponding second diffusion layer;
said plurality of wiring connects said fuses to said first diffusion layers and said second diffusion layers that correspond to the fuses.
4. A semiconductor integrated circuit device comprising:
a semiconductor substrate of one conduction type;
circuits formed on said semiconductor substrate;
power supply wiring connected to said circuits;
fuses connected to said circuits; and
a protection circuit protects said circuits, wherein said protection circuit comprising;
first diffusion layers of an opposite conduction type formed on said substrate;
well layers of the opposite conduction type formed in said substrate;
second diffusion layers of the conduction type formed in said well layers;
third diffusion layers of the opposite conduction type formed in said well layers, said third diffusion layers being connected to said power supply wiring and, with said first diffusion layers, forming sources and drains of field-effect transistors;
wiring connected to said first diffusion layers, said second diffusion layers, and said fuses.
5. The semiconductor integrated circuit device according to claim 4 , wherein said field-effect transistor is of a depletion type.
6. The semiconductor integrated circuit device according to claim 4 , wherein said circuits include-said field-effect transistors.