Interconnect Barrier Layer Formation After Via Etch Residue Removal
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Solution Overview
Problem
The etching process in semiconductor device fabrication leaves behind etching residues and by-products, which lead to oxidation of copper surfaces, degrading their quality and increasing contact resistance.
Innovation Solution
A post-etch treatment using a plasma containing an inert gas and an etchant gas is applied to remove etch residues and by-products, and to form a barrier layer on the exposed copper surfaces by re-depositing reactive species from a mask layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wet cleaning process is used to remove copper oxides, then the copper surface quality is improved, but the copper surface is damaged
Solution Approach 1:
The patent replaces the wet cleaning process (chemical/mechanical system) with a plasma-based treatment system. The plasma treatment uses reactive species to remove copper oxides through chemical reactions without the mechanical or chemical damage caused by wet cleaning, thus improving copper surface quality while preserving surface integrity
Solution Approach 2:
The patent employs an inert or controlled atmosphere during the plasma treatment process to prevent copper oxidation while cleaning the surface. The plasma environment provides a controlled chemical atmosphere that removes oxides without introducing new contaminants or causing surface damage associated with wet cleaning chemicals
2Ease of manufacture
If the etching process is used to form vias, then the opening is created, but etching residues and by-products remain on the copper surface
Solution Approach 1:
The patent converts the harmful etching residues into removable by-products through plasma treatment. The plasma process chemically reacts with the etching residues, transforming them into volatile compounds that can be easily removed, thereby eliminating the harmful effects while maintaining the via structure
Solution Approach 2:
The plasma acts as an intermediary between the etching process and the final copper surface. It provides a transition step that removes residues without requiring direct contact with harsh chemicals or mechanical tools, thus eliminating harmful factors while preserving the underlying copper structure
3Speed
If copper is used as conductive interconnect material, then high speed electrical performance is achieved, but the copper surface is prone to oxidation
Solution Approach 1:
The patent applies plasma treatment as a preliminary action before subsequent processing steps. This pre-treatment removes oxidationprone surfaces and creates a fresh, stable copper surface that is less susceptible to future oxidation, thereby maintaining both electrical performance and long-term reliability
Solution Approach 2:
The plasma treatment creates a controlled atmospheric environment that prevents copper oxidation. By treating the copper surface in a plasma environment rather than ambient air, the process eliminates oxygen exposure that would cause oxidation, thus maintaining copper surface stability while preserving electrical performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The post-etch treatment effectively prevents oxidation of copper surfaces, enhances their quality, and reduces contact resistance, thereby improving the electrical performance of semiconductor devices.
Implementation Method 1
a post-etch treatment using a plasma containing an inert gas and an etchant gas is applied to remove etch residues and by-products
Implementation Method 2
The released reactive species form a barrier layer on the exposed copper surfaces by re-depositing reactive species from a mask layer
Implementation Method 3
bombarding a surface of a mask layer of the structure using energy species formed from a plasma to release reactive species from the mask layer
Implementation Method 4
the released reactive species form a barrier layer on the exposed copper surfaces by re-depositing reactive species from a mask layer
Data Source
AI summary
Implementations of the present disclosure provide methods for preventing contact damage or oxidation after via/trench opening formation. In one example, the method includes forming an opening in a structure on the substrate to expose a portion of a surface of an electrically conductive feature, and bombarding a surface of a mask layer of the structure using energy species formed from a plasma to release reactive species from the mask layer, wherein the released reactive species form a barrier layer on the exposed surface of the electrically conductive feature.