Low resistivity high thermal-stability copper-nickel-molybdenum alloy film and producing method thereof

Abstract

A Cu—Ni—Mo alloy thin film, including Ni as a solution element and Mo as a diffusion barrier element. Ni and Mo are co-doped with Cu. The enthalpy of mixing between Mo and Cu is +19 kJ / mol, and the enthalpy of mixing between Mo and Ni is −7 kJ / mol. The atomic fraction of Mo / Ni is within the range of 0.06-0.20 or the weight faction of Mo / Ni within the range of 0.10-0.33. The total amount of Ni and Mo additions is within the range of 0.14-1.02 at. % or wt. %. A method for manufacturing the alloy thin film is also provided.

Description

technical field [0001] The invention relates to a Cu alloy thin film with low resistivity and high thermal stability. The main alloying element is Ni, and the third element Mo needs to be doped, which belongs to the field of new materials. Background technique [0002] Copper has high electrical conductivity and good resistance to electromigration, and is widely used as an interconnect metal in advanced VLSI. However, copper can react with silicon or silicon oxide at a relatively low temperature (about 200°C), causing device damage. Therefore, it is necessary to add a diffusion barrier layer between copper and silicon to block the diffusion between copper and silicon. With the gradual reduction of the feature size of the device, the thickness of the diffusion barrier layer is required to be reduced accordingly. Referring to the international semiconductor development route, for the 32nm and 22nm processes, the thickness of the diffusion barrier layer is required to be 7nm an...

AI Technical Summary

Problems solved by technology

[0006] ①The existing results are mainly based on the doping of refractory metal elements with large atomic radius. Although the precipitation of doping atoms from the copper lattice can effectively reduce the increase in resistivity caused by the distortion of the copper lattice, the second phase of precipitation is phase, and the resulting pinning effect retains a large number of dislocations and grain boundaries, etc., all increase electron scattering, so that the film resistivity can not be reduced to the ideal range.

[0007] ② It is difficult to determine the amount of dopant atoms added

As for the addition of two or more elements to prepare ternary or multi-component Cu films, how to design the amount of addition is more difficult and lacks guidance.

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