Microstructure control of copper interconnects
AssigneeAgere Systems Guardian Corp.
InventorsSailesh Mansinh Merchant, Pradip Kumar Roy
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Abstract
A method and structure is described which substantially eliminates the grain growth of copper due to self annealing. Basically, by alloying the copper interconnect e.g. with Cr, Co, Zn or Ag in an amount which does not cause a second phase or precipitation at the annealing temperature, one can control and maintain the grain size of the copper and hence achieve a uniform microstructure while improving the strength, hardness and CMP removal rate of the interconnect while substantially maintaining the conductivity of the copper.
Claims7
A method of forming an integrated circuit device having copper interconnects which are not prone to grain growth due to self annealing, comprising:
- forming a Cu seed layer having an alloy incorporated therein within a opening located within a substrate;
- forming an interconnect within said opening and on said seed layer;
- and
- annealing said seed layer and interconnect to cause said alloy to diffuse solely from said seed layer into said interconnect such that a concentration of the alloy does not exceed that which would cause a precipitate of said alloy to appear.
Dependencies are inferred from the claim text.