Method to etch cu/ta/tan selectively using dilute aqueous hf/hcl solution

a technology of etching and aqueous solution, applied in the direction of semiconductor devices, semiconductor/solid-state device details, electrical apparatus, etc., can solve the problems of reducing operational reliability, deteriorating leakage current characteristics, and device performance degradation, so as to prevent further etching and reduce potential copper diffusion damage
US20150255340A1Inactive Publication Date: 2015-09-10INTERMOLECULAR +1
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
INTERMOLECULAR
Publication Date
2015-09-10
Estimated Expiration
Not applicable · inactive patent

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Abstract

Copper can be etched with selectivity to Ta / TaN barrier liner and SiC hardmask layers, for example, to reduce the potential copper contamination. The copper film can be recessed more than the liner to further enhance the protection. Wet etch solutions including a mixture of HF and HCl can be used for selective etching copper with respect to the liner material, for example, the copper film can be recessed between 2 and 3 nm, and the barrier liner film can be recessed between 1.5 and 2 nm.
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Description

FIELD OF THE INVENTION

[0001] The present invention relates generally to methods for fabricating an integrated-circuit device, and particularly to selective wet etches processes between copper, tantalum and tantalum nitride.BACKGROUND OF THE INVENTION

[0002] Current technologies for fabricating ultra-large scale integrated-circuit devices employ copper interconnects. Interconnections using copper have replaced aluminum in the fabrication of ultra-large scale integrated-circuit devices due to its lower specific resistance and improved electromigration (EM) characteristics.

[0003] Usually, the copper interconnects are surrounded by barrier liners, such as tantalum (Ta) and / or tantalum nitride (TaN), to prevent outdiffusion and corrosion of the copper interconnect lines. For example, copper can diffuse into the surrounding dielectric materials at low temperatures, leading to device performance degradation. Copper can also be oxidized and corroded during the standard processing of device fabr...

Claims

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