Low-k Dielectric Film Patterning via Nitrogen-Free Plasma
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Solution Overview
Problem
Current low-k dielectric processing technologies face challenges in minimizing damage to low-k dielectric films during etching, particularly due to sidewall damage and 'F memory effect' from fluorocarbon-based etching processes, which affect the mechanical integrity and electrical properties of the films.
Innovation Solution
The method involves a two-stage plasma etching process using nitrogen-free and remote plasma processes, employing Si-based precursors and inert gases to form protective sidewall depositions, followed by selective removal of etch residues with NF3/NH3 or O2/N2/NF3 plasmas, avoiding fluorocarbon chemistry to minimize damage and maintain the dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluorocarbon-based etching processes are used to pattern low-k dielectric films, then etching capability is improved, but sidewall damage and F memory effect occur which deteriorate mechanical integrity and electrical properties
Solution Approach 1:
The patent extracts and removes fluorocarbon chemistry from the etching process entirely, replacing it with hydrocarbon-based chemistry. This eliminates the source of F memory effect and sidewall damage while maintaining etching capability through alternative chemical mechanisms that do not introduce harmful fluorine residues
Solution Approach 2:
The patent changes the chemical composition parameters of the etching process by substituting fluorocarbon precursors with hydrocarbon precursors. This parameter change fundamentally alters the chemistry to eliminate harmful fluorine-based side effects while preserving the etching function through different reaction pathways
2Manufacturing precision
If conventional etching processes are used, then patterning is achieved, but mechanical integrity and electrical properties of low-k dielectric films deteriorate
Solution Approach 1:
The patent introduces an intermediary protective layer formed by hydrocarbon deposition during the etching process. This intermediary layer protects the low-k dielectric sidewalls from direct plasma damage while allowing the etching to proceed, thereby maintaining both patterning precision and film integrity
Solution Approach 2:
The patent converts the typically harmful plasma exposure into a beneficial process by using controlled hydrocarbon deposition during etching. The same plasma that performs etching simultaneously deposits protective hydrocarbon layers on sidewalls, transforming a damaging process into one that preserves mechanical and electrical properties
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 reduces damage to low-k dielectric films, maintains their mechanical integrity, and prevents undesirable changes in dielectric constant, enabling more precise and effective patterning with reduced post-etch clean requirements.
Implementation Method 1
modifying exposed portions of the low-k dielectric layer with a nitrogen-free plasma process
Implementation Method 2
removing, with a remote plasma process, the modified portions of the low-k dielectric layer selective to the mask layer and unmodified portions of the low-k dielectric layer
Implementation Method 3
The method also involves modifying exposed portions of the low-k dielectric layer with a plasma process, the modifying performed by using a first protection layer deposition process
Data Source
AI summary
Methods of patterning low-k dielectric films are described. In an example, a method of patterning a low-k dielectric film involves forming and patterning a mask layer above a low-k dielectric layer, the low-k dielectric layer disposed above a substrate. The method also involves modifying exposed portions of the low-k dielectric layer with a nitrogen-free plasma process. The method also involves removing, with a remote plasma process, the modified portions of the low-k dielectric layer selective to the mask layer and unmodified portions of the low-k dielectric layer.