Non-Plasma Etch of Titanium Layers with Tunable Selectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current etch techniques for titanium (Ti) and titanium nitride (TiN) in semiconductor manufacturing face challenges such as selectivity, pattern damage, and pattern collapse, especially in high aspect ratio features and ten nanometer technology nodes and below, due to difficulties in achieving selective etching without damaging patterns.
Innovation Solution
A non-plasma etch process, including gas-phase and remote plasma etch, is used to selectively etch titanium-containing material layers with tunable selectivity to other materials by exposing substrates to halogen-containing gases like fluorine-based gases, allowing for controlled etching of materials like tungsten, tungsten oxide, and hafnium oxide, while modulating process parameters like temperature to achieve target etch parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etch processes are used to etch titanium-containing material layers, then etching capability is improved, but pattern damage occurs
Solution Approach 1:
The patent replaces plasma-based etching (which causes pattern damage through ion bombardment and reactive species) with a non-plasma gas-phase etching process using halogen-containing gases. This substitution eliminates the harmful mechanical and chemical effects of plasma on photoresist patterns while maintaining effective etching capability through controlled gas-phase reactions at elevated temperatures.
Solution Approach 2:
The patent changes the process parameters by operating at elevated temperatures (e.g., 80-150°C or higher) in a non-plasma environment with halogen-containing gases. This parameter change enables selective etching of titanium-containing materials without the damaging effects of plasma, achieving both high etching capability and pattern integrity.
2Manufacturing precision
If wet etch processes are used to etch titanium-containing material layers, then selectivity is improved, but pattern collapse occurs
Solution Approach 1:
The patent replaces wet chemical etching with a non-plasma gas-phase etching process. This substitution maintains the selectivity benefits of chemical etching while eliminating the liquid-phase effects that cause pattern collapse, as the gas-phase process provides better support for high aspect ratio structures during etching.
Solution Approach 2:
The patent uses gas-phase halogen-containing etchants instead of liquid etchants. This pneumatic approach allows the etching process to occur in a gaseous environment that provides mechanical support to pattern structures, preventing collapse while maintaining chemical selectivity through controlled gas-phase reactions.
3Speed
If conventional etch techniques are used for high aspect ratio features, then etching speed is improved, but selectivity control becomes difficult
Solution Approach 1:
The patent employs elevated temperature processing (80-150°C or higher) in combination with halogen-containing gases to achieve fast etching rates while maintaining excellent selectivity control. The temperature parameter enables rapid reaction kinetics for high-speed etching, while the non-plasma gas-phase environment provides precise selectivity control through controlled chemical reactions.
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 enables selective and non-selective etching of titanium-containing layers with improved pattern integrity and selectivity, reducing pattern damage and collapse, and is applicable for interconnect patterning and other microelectronic workpiece processes.
Implementation Method 1
selectively etching the at least one additional material layer with respect to the titanium-containing material layer by exposing the substrate to a controlled environment including a halogen-containing gas
Implementation Method 2
A non-plasma etch process, including gas-phase and remote plasma etch, is used to selectively etch titanium-containing material layers
Data Source
AI summary
Embodiments provide a non-plasma etch, such as a gas-phase and/or remote plasma etch, of titanium-containing material layers with tunable selectivity to other material layers. A substrate is received within a process chamber, and the substrate has exposed material layers including a titanium-containing material layer and at least one additional material layer. The additional material layer is selectively etched with respect to the titanium-containing material layer by exposing the substrate to a controlled environment including a halogen-containing gas. For one embodiment, the halogen-containing gas includes a fluorine-based gas. For one embodiment, the titanium-containing material layer is a titanium or a titanium nitride material layer. For one embodiment, the additional material layer includes tungsten, tungsten oxide, hafnium oxide, silicon oxide, silicon-germanium, silicon, silicon nitride, and/or aluminum oxide. A non-selective etch with respect to the titanium-containing material layer can be performed by modulating the process parameters such as temperature.