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Method of Etching Cu in High Aspect Ratio Geometry

IP.com Disclosure Number: IPCOM000245402D
Publication Date: 2016-Mar-07
Document File: 6 page(s) / 147K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to use a unique, optimized film stack that gouges Copper (Cu) with Helium (He) plasma and application.

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Method of Etching Cu in High Aspect Ratio Geometry


Scaling interconnect node requires lower via resistance due to the exponential increase in via resistance for conventional Atomic Layer Deposition (ALD)/ Physical vapor deposition (PVD) Tantalum nitride (TaN) and exotic liners, Carbon monoxide (Co), ruthenium (Ru), to enable metallization. Numerous techniques to reduce resistance require Cu gouging to increase the contact surface area.

Prior art recommendations are not ideal for integration and inefficient process flow, requiring ex-situ gouge process for trench first metal hard mask (TFMH) integration in the PVD chamber.

New chemistries and plasma conditions are required to etch/gouge Cu without deleterious effect to dielectric and hardmask.

The novel solution is a method to use a unique, optimized film stack that gouges Cu with Helium (He) plasma and application.

The plasma condition controls Cu gouge and is benign to dielectric attack with minimal loss of hardmask. A protective film forms to protect Cu loss in subsequent processes. Selective gouge performs as a function of via size (nominal deeper and less LRG via.

One embodiment is a Reactive Ion Etching (RIE) platform tool with Capacitive Coupled Plasmas (CCP) /Inductive Coupled Plasmas (ICP) chamber capabilities for vacuum seal processing of dielectric RIE follow by Gouge RIE.

Implementation requires:


 ICP Chamber Design


 Condition 1 : 1 mT/1500Ws/950Wb /20C2H4/30O2/65C/60s

 Condition 2: 5 mT/500W...