Silicon Nitride Deposition Using TSA Pulses for Low Hydrogen Films
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Solution Overview
Problem
Existing deposition methods for silicon nitride films on wafers face challenges in achieving low hydrogen density and high wet etch resistance, which are critical for improving film quality and reliability.
Innovation Solution
The method involves intermittently supplying trisilylamine (TSA) into a processing chamber, where the Si—H bond of TSA is broken at elevated temperatures, allowing for the deposition of a silicon nitride film with low hydrogen density and high wet etch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon nitride film is deposited using conventional methods with silane-based gas and nitride gas, then the deposition process can be completed, but the resulting film has high hydrogen density and low wet etch resistance
Solution Approach 1:
The patent changes the chemical composition parameter of the precursor gas from conventional silane-based gas to trisilylamine (TSA). This parameter change fundamentally alters the deposition chemistry, enabling the formation of silicon nitride film with low hydrogen density and high wet etch resistance. The TSA molecule structure (SiH3)3N provides a different reaction pathway that inherently reduces hydrogen incorporation in the film.
Solution Approach 2:
The patent employs periodic intermittent supply of trisilylamine gas into the processing chamber, alternating with inert gas purging cycles. This periodic action allows controlled deposition while maintaining low hydrogen density by removing excess hydrogen-containing species between deposition pulses, thereby achieving high wet etch resistance.
2Reliability
If trisilylamine is intermittently supplied into the processing chamber, then the hydrogen density in the film is reduced and wet etch resistance is improved, but the deposition process becomes more complex
Solution Approach 1:
The intermittent supply method uses periodic cycles of TSA gas introduction followed by inert gas purging. This periodic action simplifies process control by using straightforward gas flow switching rather than complex real-time parameter adjustments, achieving low hydrogen density through temporal separation of deposition and purification phases.
Solution Approach 2:
An inert gas is introduced as an intermediary medium to purge the processing chamber between TSA supply cycles. This intermediary gas facilitates the removal of excess hydrogen-containing species without reacting with the silicon nitride film, simplifying the overall process by providing a clean, non-reactive clearing mechanism.
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 a silicon nitride film with enhanced wet etch resistance and reduced hydrogen density, improving the film's quality and performance.
Implementation Method 1
the Si—H bond of TSA is broken at elevated temperatures, allowing for the deposition of a silicon nitride film
Implementation Method 2
depositing the silicon nitride film on the surface of the substrate by intermittently supplying trisilylamine into a processing chamber accommodating the substrate
Data Source
AI summary
With respect to a method of depositing a silicon nitride film on a surface of a substrate, the method includes depositing the silicon nitride film on the surface of the substrate by intermittently supplying trisilylamine into a processing chamber accommodating the substrate.