Method of forming an aluminum conductor with highly oriented grain structure

Claim 1

A method for reducing electromigration of aluminum or aluminum alloy polycrystalline conductors on a dielectric layer of a semiconductor device comprising: (a) etching an array of columns of holes at least three hole wide rows in said dielectric layer, said holes extending only partially through said layer in a line pattern corresponding to that of a desiring interconnection pattern, the pitch of said holes being about 1/2-5 μm and said holes having a depth of 1/10-1/2 μm, (b) depositing a thin film of aluminum or aluminum alloy of a thickness at least sufficient to fill said holes on the surface of said dielectric layer provided with said holes, (c) scanning said film of aluminum or aluminum alloy with a laser beam of an intensity sufficient to melt said film and cause it to flow and be planarized and upon cooling forming an oriented crystal structure with grain boundaries aligned orthogonally to rows and columns of the hole pattern, (d) aligning a photoresist mask with said crystal structure in a manner such that grain boundaries extend substantially only in a direction across the width of the desired conductor lines, and (e) then removing aluminum material from said crystal structure outside of said desired conductor lines by plasma etching said crystal structure thorough said aligned photoresist mask.

Claim 2

A method for reducing electromigration of aluminum or aluminum alloy polycrystalline conductors on a dielectric layer of a semiconductor device comprising: (a) etching an array of columns of holes at least three hole wide rows in said dielectric layer, said holes extending only partially through said layer in a line pattern corresponding to that of a desiring interconnection pattern, the pitch of said holes being about 1/2-5 μm and said holes having a depth of 1/10-1/2 μm, (b) depositing a thin film of aluminum or aluminum alloy of a thickness at least sufficient to fill said holes on the surface of said dielectric layer provided with said holes, (c) scanning said film of aluminum or aluminum alloy with a laser beam of an intensity sufficient to melt said film and cause it to flow and be planarized and upon cooling forming an oriented crystal structure with grain boundaries aligned orthogonally to rows and columns of the hole pattern, (d) aligning a photoresist mask with said crystal structure in a manner such that grain boundaries extend substantially only in a direction across the width of the desired conductor lines, and (e) then removing aluminum material from said crystal structure outside of said desired conductor lines by plasma etching said crystal structure thorough said aligned photoresist mask.