Halide-Free ALD Oxide Undercoating for PEALD Chamber Contamination
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Solution Overview
Problem
In the semiconductor industry, the deposition of silicon nitride films in plasma enhanced atomic layer deposition (PEALD) chambers faces challenges due to the incorporation of aluminum-containing byproducts from halide-based chemistry, leading to high post-clean metals contamination, which is non-repeatable and limits wafer processing throughput.
Innovation Solution
A method involving a halide-free atomic layer deposition (ALD) oxide undercoating is used to suppress aluminum-rich byproducts, combined with a lower-temperature NF3-based clean and a conformal ALD oxide undercoat, allowing for repeated in-situ deposition/clean cycles, thereby reducing aluminum contamination and enabling metals-free ALD SiN wafer processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If halide-based chemistry is used for silicon nitride deposition, then deposition rate is improved, but aluminum contamination increases
Solution Approach 1:
A halide-free ALD oxide undercoating is introduced as an intermediary layer between the chamber surfaces and the silicon nitride deposition process. This undercoating suppresses the formation of aluminum-rich byproducts during halide-based chemistry, allowing high-rate deposition while maintaining low aluminum contamination levels
Solution Approach 2:
The halide-free ALD oxide undercoating is deposited in advance before the silicon nitride deposition begins. This preliminary action prepares the chamber surfaces to prevent aluminum contamination during subsequent halide-based deposition cycles
2Manufacturing precision
If frequent chamber cleans are performed to reduce aluminum contamination, then metal purity is improved, but tool uptime decreases
Solution Approach 1:
The halide-free ALD oxide undercoating is deposited in advance before contamination becomes problematic. This preliminary protective layer allows extended processing periods without cleaning, maintaining metal purity while maximizing tool uptime
Solution Approach 2:
The halide-free ALD oxide undercoating acts as a sacrificial protective layer that can be depleted over time. When it becomes thin or contaminated, a simple clean restores the chamber surfaces, avoiding the need for frequent complete chamber disassembly and reassembly
3Manufacturing precision
If replaceable liners are used to prevent aluminum contamination, then metal purity is improved, but device complexity and cost increase
Solution Approach 1:
The halide-free ALD oxide undercoating serves as a chemical intermediary that protects chamber surfaces without requiring physical liners. This approach maintains metal purity while avoiding the complexity of replaceable liner components
Solution Approach 2:
The patent replaces mechanical/physical protection methods (replaceable liners) with a chemical protection method (halide-free ALD oxide undercoating). This substitution eliminates the need for complex liner installation and removal mechanisms while achieving the same contamination prevention goal
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 results in high-throughput, repeatable deposition of ALD SiN films that meet stringent in-film metals requirements, improving tool uptime and reducing cost-of-ownership by minimizing the need for frequent chamber cleans and replaceable liners.
Implementation Method 1
cleaning the ceramic surfaces of the pedestal and showerhead with a fluorine plasma
Implementation Method 2
depositing a conformal halide-free atomic layer deposition (ALD) oxide undercoating on the ceramic surfaces
Implementation Method 3
plasma enhanced atomic layer deposition (PEALD)
Data Source
AI summary
A method of depositing ALD films on semiconductor substrates processed in a micro-volume of a plasma enhanced atomic layer deposition (PEALD) reaction chamber wherein a single semiconductor substrate is supported on a ceramic surface of a pedestal and process gas is introduced through gas outlets in a ceramic surface of a showerhead into a reaction zone above the semiconductor substrate, includes (a) cleaning the ceramic surfaces of the pedestal and showerhead with a fluorine plasma such that aluminum-rich byproducts are formed on the ceramic surfaces, (b) depositing a conformal halide-free atomic layer deposition (ALD) oxide undercoating on the ceramic surfaces so as to cover the aluminum-rich byproducts, (c) depositing a pre-coating on the halide-free ALD oxide undercoating, and (d) processing a batch of semiconductor substrates by transferring each semiconductor substrate into the reaction chamber and depositing a film on the semiconductor substrate supported on the ceramic surface of the pedestal.