Silicon Nitride Trench Deposition for Conformal Sidewalls
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Solution Overview
Problem
Existing methods for forming silicon nitride films in trenches of substrates suffer from poor conformality, which affects the quality and uniformity of sidewalls used in large-scale integrated circuits.
Innovation Solution
A method involving plasma-enhanced atomic layer deposition (PEALD) with specific gas purging and plasma exposure sequences, including the use of silicon and nitrogen-containing gases, and optionally hydrogen, to form a silicon nitride thin film with enhanced conformality, achieved by precise timing and gas introduction steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional PEALD process is used to form SiN film in trench, then the film can be deposited, but the conformality is poor
Solution Approach 1:
The deposition process is segmented into multiple alternating steps: silicon precursor exposure, nitrogen gas purging, and plasma exposure. This segmentation allows each step to perform its specific function optimally, with purging steps removing excess precursor from trench regions before plasma activation, thereby improving conformality through controlled sequential deposition
Solution Approach 2:
Nitrogen-containing gas purging is performed as a preliminary action before plasma exposure to remove excess silicon precursor from the trench. This preliminary purging prevents precursor accumulation that would lead to poor conformality, ensuring that the subsequent plasma step deposits material uniformly across the trench structure
2Manufacturing precision
If multiple gas introduction and purging steps are implemented to improve conformality, then film uniformity improves, but process time increases
Solution Approach 1:
The process maintains continuous useful action by alternating between deposition steps (silicon precursor introduction) and purging steps (nitrogen gas exposure) without idle periods. Each step is optimized to complete its function efficiently, with the nitrogen purging simultaneously preparing the surface for the next deposition cycle, thereby maintaining film uniformity while minimizing total process time
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 conformality of over 90% in silicon nitride thin films, improving the uniformity and quality of sidewalls in trenches, enhancing the performance of large-scale integrated circuits.
Implementation Method 1
exposing the substrate to reactive species generated by a plasma from the nitrogen-containing gas
Implementation Method 2
A method involving plasma-enhanced atomic layer deposition (PEALD) with specific gas purging and plasma exposure sequences
Data Source
AI summary
A method of depositing a silicon nitride thin film is provided. The method may comprise steps of: (a) placing a substrate on a susceptor in a reaction chamber; wherein the substrate comprises a trench; (b) introducing a silicon precursor into the reaction space; (c) exposing the substrate to a nitrogen-containing gas to purge excess silicon precursor and byproducts; (d) introducing the silicon precursor into the reaction space; (e) exposing the substrate to the nitrogen-containing gas to purge excess silicon precursor and byproducts; (f) exposing the substrate to reactive species generated by a plasma from the nitrogen-containing gas; and (g) exposing the substrate to the nitrogen-containing gas to purge excess reactive species and byproducts.