Fuse window guard ring structure for nitride capped self aligned contact processes

A method of forming a moisture barrier guard ring structure for an integrated circuit on a substrate;

• said substrate having a fuse window area and device areas;
• comprising the steps of:
• a) forming an isolation region over a substrate having fuse window area;
• said isolation region covering at least said fuse window area;
• b) forming a fuse structure over said isolation regions cross said fuse window area;
• said fuse structure formed by forming a polysilicon fuse and a fuse dielectric layer over said isolation region;
• forming sidewall spacers on the sidewalls of said polysilicon fuse and said fuse dielectric layer;
• c) forming a cap layer composed of silicon nitride over said fuse, said isolation region and said substrate;
• d) forming an interlevel dielectric layer over said fuse, said isolation region, said cap layer, and said substrate surface;
• said interlevel dielectric layer is composed of BPTEOS/PETEOS and preferably having a thickness in a range of between about 4000 and 11,000 .ANG.;
• e) forming a first annular ring over said isolation region surrounding said fuse window area and over said fuse structure;
• said first annular ring forming a moisture proof seal with said cap layer over said fuse structure;
• f) forming a first conductive wiring line over said first annular ring;said first conductive wiring line composed of a material selected from the group consisting of Al, Al alloy, W, TiW, and AlCu and said first conductive wiring line has a thickness in a range of between about 1000 and 6000 .ANG.;
• g) forming an inter metal dielectric layer over said interlevel dielectric layer and said first conductive wiring line;
• said inter metal dielectric layer composed of a material selected from the group consisting of PEOX, PETEOS, O3TEOS BPSG, and PSG, and said inter metal dielectric layer having a thickness in a range of between about 3000 and 11,000 .ANG.;
• h) forming a second annular ring through said inter metal dielectric layer on said first conductive wiring line;
• said second annular ring is composed of a material selected from the group consisting of Al, AlCu, and Tungsten, and said second annular ring has a thickness in a range of between about 3000 and 11,000 .ANG.;
• i) forming a second conductive wiring line over said second annular ring;
• said second conductive wiring line composed of a material selected from the group consisting of Al, TiN, and AlCu;
• and said second conductive line thickness in a range of between about 2000 and 8000 .ANG.;
• j) forming a passivation layer comprised of a first oxide passivation layer and a first silicon nitride passivation layer over said second conductive wiring line and said inter metal dielectric layer;
• k) forming a fuse window through said passivation layer and partially through said inter metal dielectric layer over said fuse window area whereby a moisture proof guard ring structure is comprised of said first annular ring, said first conductive wiring line, said second annular ring;
• said second conductive wiring line;
• said moisture proof guard ring structure surrounding said fuse window area;
• said fuse window having a depth from the passivation layer surface in a range of between about 3000 and 15,000 .ANG..