Dual-rie structure for via/line interconnections
AssigneeInternational Business Machines Corporation
InventorsChristopher Adam Feild, Roy Charles Iggulden, Rajiv Vasant Joshi, Edward William Kiewra
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Abstract
A structure and process to define a via/interconnect structure is described. The structure is formed by reactive ion etching (RIE) where vias are formed first then the interconnects. The disclosed method relies on first depositing a metal with a thickness equivalent to the total height of the via and interconnect. Once vias are delineated by forming a hard mask and lithography, the lines are patterned using a lithographic step. Vias and lines are formed using lithography and RIE in one step and interfacial integrity is maintained resulting in high electromigration performance.
Claims20
A method of forming a via/interconnect structure comprising the steps of:
- (a) forming a metal stack on a surface of a substrate, said metal stack comprising deposition of at least a first metal layer and a second metal layer;
- (b) forming a masking layer on said metal stack;
- (c) patterning said masking layer providing a via mask on said metal stack;
- (d) etching said metal stack using said via mask to first define vias in said metal stack and thereafter, and at the same time, metal lines, said vias being composed of said second metal layer and said metal lines being composed of said first metal layer;
- (e) depositing a dielectric layer on the structure provided in step (d);
- and
- (f) planarizing the dielectric layer stopping on said vias.
A method of forming a via/interconnect structure comprising the steps of:
- (a) depositing a first metal layer on a surface of a substrate;
- (b) forming a metal line from said first metal layer by lithography and reactive-ion etching (RIE);
- (c) depositing a second metal layer on said metal line;
- (d) forming a via from said second metal layer by lithography and RIE;
- and
- (e) forming a dielectric layer surrounding said metal line and said via, said dielectric layer containing a void therein.
Dependencies are inferred from the claim text.