Yttrium-Containing Films for TiN Etch Selectivity
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Solution Overview
Problem
Current materials, such as SiN, TiO2, HfO2, and ZrO2, lack sufficient dry etch selectivity to titanium nitride (TiN) using halide-based reactive ion etches, necessitating the development of new etch contrast materials for semiconductor manufacturing.
Innovation Solution
Atomic layer deposition methods using yttrium precursors to form yttrium nitride or oxide films with high etch selectivity, involving exposure to nitrogen or oxygen reactants, and incorporating silicon precursors to create silicon-yttrium nitride films, which provide enhanced etch contrast to TiN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common materials such as SiN, TiO2, HfO2, and ZrO2 are used as protective films, then the device structure can be formed, but the etch selectivity to TiN is insufficient for halide-based reactive ion etching
Solution Approach 1:
The patent changes the material composition parameters by introducing yttrium-containing films with specific stoichiometries (Y3N4, Y2O3, or mixed phases) to achieve the required etch selectivity. The yttrium film composition is controlled through atomic layer deposition process parameters including precursor selection (Y(EtCp)2(hfac), Y(EtCp)3, Y(MeCp)2(hfac)) and reaction conditions, enabling tailored etch resistance while maintaining device compatibility
Solution Approach 2:
The patent employs composite material strategies by creating yttrium-based films that can exist as pure phases (Y3N4 or Y2O3) or mixed phases, providing both the necessary etch selectivity and compatibility with existing device structures. The composite nature allows optimization of both protective function and integration with standard semiconductor materials
2Manufacturing precision
If lithographic techniques are used for patterning, then precise patterns can be formed, but the process steps and costs increase
Solution Approach 1:
The patent extracts the patterning function from the lithography process by using etch-selective yttrium films as self-aligned masks. The yttrium film's high selectivity to halide-based etchants allows direct pattern transfer without requiring separate lithography steps, thereby simplifying the manufacturing process and improving productivity while maintaining precision
Solution Approach 2:
The yttrium-containing film serves a dual function: it acts as both the protective layer and the patterning definition layer. The film's inherent etch selectivity enables it to automatically define pattern boundaries during the etch process without requiring additional lithographic intervention, making the system self-sufficient for patterning operations
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 method achieves high etch selectivity and prevents copper diffusion, allowing for efficient patterning in semiconductor manufacturing while maintaining the ability to remove films through chemical-mechanical planarization.
Implementation Method 1
Atomic layer deposition methods using yttrium precursors to form yttrium nitride or oxide films
Implementation Method 2
The substrate may be exposed to a pretreatment process... plasma
Data Source
AI summary
Methods for depositing a yttrium-containing film through an atomic layer deposition process are described. Some embodiments of the disclosure utilize a plasma-enhanced atomic layer deposition process. Also described is an apparatus for performing the atomic layer deposition of the yttrium containing films.