Cobalt Interconnect Metallization for Fluorocarbon Dielectric Stability
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Solution Overview
Problem
Fluorocarbon-based dielectric materials used in integrated circuits (ICs) outgas reactive fluorine-based compounds during backend thermal processing, leading to the formation of volatile compounds with interconnect materials like tantalum nitride, which can cause failure of the interlayer dielectric stack.
Innovation Solution
The use of cobalt (Co) or ruthenium (Ru) as interconnect materials in conjunction with a fluorocarbon-based dielectric material, which resists the formation of volatile compounds and acts as a barrier liner to prevent oxidation and corrosion, thereby stabilizing the interconnect structures during thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fluorocarbon-based dielectric material is used to reduce dielectric constant, then lower polarizability and lower k-value are achieved, but reactive fluorine compounds outgas during thermal processing and form volatile compounds with interconnect materials
Solution Approach 1:
A barrier liner material is introduced as an intermediary layer between the fluorocarbon-based dielectric material and the interconnect material. This barrier liner prevents direct contact and chemical reaction between the outgassed fluorine compounds and the interconnect material, thereby eliminating the formation of volatile compounds while allowing the low-k dielectric material to function effectively.
Solution Approach 2:
The outgassed fluorine compounds, which were previously harmful and caused volatile compound formation, are now managed by the barrier liner that converts this harmful effect into a controlled process. The barrier liner absorbs or blocks the fluorine compounds, preventing damage to the interconnect structure while maintaining the benefits of the fluorocarbon dielectric material.
2Reliability
If tantalum nitride is used as interconnect material, then good electrical conductivity is achieved, but volatile compounds form when exposed to fluorine-based compounds during thermal processing
Solution Approach 1:
The barrier liner serves as a protective intermediary between the tantalum nitride interconnect material and the fluorine-based compounds. It physically separates these two components during thermal processing, preventing the formation of volatile compounds while allowing the tantalum nitride to maintain its electrical conductivity function.
Solution Approach 2:
The barrier liner creates a chemically inert environment around the tantalum nitride interconnect material by blocking exposure to reactive fluorine compounds. This protective barrier ensures the chemical stability of the interconnect material during thermal processing while preserving its electrical properties.
3Reliability
If barrier liner is added to prevent volatile compound formation, then interconnect stability is improved, but process complexity increases
Solution Approach 1:
The barrier liner is designed with optimized thickness parameters and material composition that allow it to provide effective protection against volatile compound formation. By carefully controlling these parameters, the barrier liner achieves maximum protective function with minimal added complexity to the overall device structure.
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
This approach prevents the formation of volatile compounds, ensuring the integrity of the interlayer dielectric stack and maintaining the functionality of the ICs during backend processing.
Implementation Method 1
acts as a barrier liner to prevent oxidation and corrosion
Implementation Method 2
fluorine-based compounds such as, for example, fluorocarbons (CFn) and hydrogen fluoride (HF) may outgas during elevated temperatures associated with backend thermal processing
Implementation Method 3
resists the formation of volatile compounds
Data Source
AI summary
Embodiments of the present disclosure are directed towards metallization of a fluorocarbon-based dielectric material for interconnect applications. In one embodiment, an apparatus includes a semiconductor substrate, a device layer disposed on the semiconductor substrate, the device layer including one or more transistor devices, and an interconnect layer disposed on the device layer, the interconnect layer comprising a fluorocarbon-based dielectric material, where x represents a stoichiometric quantity of fluorine relative to carbon in the dielectric material, and one or more interconnect structures configured to route electrical signals to or from the one or more transistor devices, the one or more interconnect structures comprising cobalt (Co), or ruthenium (Ru), or combinations thereof. Other embodiments may be described and/or claimed.