Direct Plasma Gap Fill for Void-Free Silicon Nitride Deposition
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Solution Overview
Problem
In semiconductor manufacturing, existing gap-fill processes using chemical vapor deposition (CVD) struggle to fill gaps with high aspect ratios without voids, as the film formation rate varies across the gap, leading to void formation due to differences in upper and lower region deposition rates.
Innovation Solution
A substrate processing method involving the use of oligomeric silicon precursors and nitrogen-containing gases, with direct plasma generation and varying process parameters across sub-steps to form a flowable silicon nitride film, which is then converted to silicon oxide and densified to ensure uniform film quality across the gap depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical vapor deposition (CVD) or plasma chemical vapor deposition (PECVD) is used to deposit film on substrate, then film-forming rate is fast, but film formation rate in upper region of gap is relatively higher than in lower region, causing entrance region to close first and forming voids
Solution Approach 1:
The gap-fill process is divided into multiple sequential steps with different process parameters. The first step uses parameters optimized for lower region filling (higher temperature, lower pressure), while subsequent steps use parameters optimized for upper region filling (lower temperature, higher pressure), preventing void formation by controlling differential deposition rates across the gap depth
Solution Approach 2:
The patent changes process parameters (temperature, pressure, gas flow rates) between different filling steps to control the film formation rate distribution. By adjusting these parameters, the deposition rate in the upper region is reduced relative to the lower region, preventing entrance closure and void formation while maintaining overall fast filling
2Adaptability or versatility
If gap-fill process is performed on substrate with high aspect ratio gaps, then integration density increases, but it becomes difficult to fill the inside of gap without voids due to limitations of known deposition processes
Solution Approach 1:
The filling process for high aspect ratio gaps is segmented into multiple steps, each targeting different regions of the gap. This segmented approach allows precise control over film deposition in challenging high aspect ratio structures, ensuring complete void-free filling that single-step processes cannot achieve
Solution Approach 2:
The patent employs dynamic adjustment of process parameters during the filling sequence. By making the process adaptive and dynamic rather than static, the system can respond to the specific geometry of high aspect ratio gaps and ensure reliable void-free filling across varying aspect ratios
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 method effectively prevents void formation and ensures a uniform, dense film fill across the entire gap depth, improving the reliability and quality of semiconductor manufacturing processes.
Implementation Method 1
generating plasma directly in a reaction space by applying a voltage to at least one of the substrate support unit and the gas supply unit
Implementation Method 2
supplying an oligomeric silicon precursor and a nitrogen-containing gas onto the substrate through a gas supply unit on the substrate support unit, and generating plasma directly in a reaction space
Data Source
AI summary
A method of processing a substrate having a gap includes loading the substrate onto a substrate support unit, supplying an oligomeric silicon precursor and a nitrogen-containing gas onto the substrate on the substrate support unit through a gas supply unit, and generating plasma directly in a reaction space by applying a voltage to at least one of the substrate support unit and the gas supply unit, wherein a plurality of sub-steps are performed during the supplying of the oligomeric silicon precursor, the nitrogen-containing gas and the generating a direct plasma, wherein different process parameters are applied during the plurality of sub-steps.