Method for selectively depositing diffusion barrier for copper interconnection

Abstract

The invention belongs to the technical field of integrated circuits and particularly discloses a method for selectively depositing a diffusion barrier for copper interconnection, which comprises a step of before depositing the diffusion barrier, coating a layer of organic group on an exposed copper surface to prevent the absorption of a precursor on the copper surface in an atomic layer depositing process to selectively deposit the diffusion barrier. In the method, the deposition of the diffusion barrier in places except for the bottom of a copper interconnection hole is realized, so the unnecessary diffusion barrier in the copper through hole is removed and the contact resistance in the through hole is reduced. Thus, the resistance of the system is reduced and consequentially the RC delay of the whole circuit is reduced.

Description

technical field [0001] The invention belongs to the technical field of large-scale integrated circuits and relates to a technology for depositing a diffusion barrier layer, in particular to a method for selectively depositing a diffusion barrier layer for copper interconnection. Background technique [0002] With the continuous advancement of VLSI process technology, the feature size of semiconductor devices is getting smaller and smaller, and the integration level is getting higher and higher. The thinner metal wires designed in VLSI will increase the metal resistance and generate more heat. , resulting in serious electromigration phenomenon, and at the same time, the delay (RCDelay) caused by the increase of inter-line capacitance and metal resistance is also deteriorating, which greatly affects the performance of semiconductor chips. [0003] Compared with conventional aluminum, copper has the following advantages: First, the resistivity of copper is smaller (Cu: 1.7 μΩ / c...

AI Technical Summary

Problems solved by technology

As the integrated circuit technology node moves to a process below 45nm, the size of the through-hole in the back-end interconnection technology becomes smaller and smaller. The diffusion barrier layer grown at the bottom of the through-hole and the two interfaces of the copper wire and the copper through-hole, And the diffusion barrier layer itself accounts for a large proportion of the resistance of the entire via, so the contact resistance and interconnect resistance will increase accordingly, increasing the RC interconnect delay of the circuit

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