High-Aspect-Ratio Gap Fill Using Silicon Nitride-to-Oxide Conversion
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Solution Overview
Problem
The existing gap-fill processes in semiconductor manufacturing struggle to achieve uniform and dense silicon oxide film formation in the lower regions of gaps with high aspect ratios, often resulting in voids, seams, micropores, and delamination.
Innovation Solution
A substrate processing method involving partial filling of gaps with a flowable silicon nitride film, followed by conversion to silicon oxide film, and subsequent full filling with silicon nitride film, ensuring the silicon oxide film is uniformly and densely formed by controlling the thickness and process conditions, including the use of oligomeric silicon precursors and oxygen-containing gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a gap is filled with a silicon oxide film through a general FCVD technology, then the gap filling process can be completed, but the conversion into a silicon oxide film is not uniform and dense in the lower region of the gap compared with the upper region
Solution Approach 1:
The gap filling process is divided into multiple sequential steps: first filling the gap with a flowable silicon nitride film, then converting it to silicon oxide, and finally filling any remaining voids. This segmentation allows each step to optimize for its specific function, ensuring uniform and dense film formation throughout the entire gap including the lower region.
Solution Approach 2:
The silicon nitride film is deposited as an intermediate layer before final silicon oxide formation. This preliminary action creates a flowable precursor that can uniformly fill the gap structure, which is then converted to the desired silicon oxide material, ensuring both uniformity and density in the final product.
2Productivity
If a gap with high aspect ratio is filled using conventional methods, then the gap can be filled, but voids, seams, micropores and delamination occur
Solution Approach 1:
The process utilizes changes in material properties - specifically the flowable nature of silicon nitride film during deposition, its conversion to silicon oxide, and the control of film thickness parameters. By adjusting these parameters sequentially, the process achieves complete gap filling without defects while maintaining high productivity.
Solution Approach 2:
The method employs a composite approach using two different materials - silicon nitride as a flowable precursor and silicon oxide as the final material. This composite strategy leverages the advantageous properties of each material: the flowability of silicon nitride for uniform filling and the desired electrical and mechanical properties of silicon oxide for the final structure.
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 suppresses micropores and delamination, achieving improved density and uniformity of silicon oxide films in high-aspect-ratio gaps, enhancing the reliability of semiconductor devices.
Implementation Method 1
forming a silicon oxide film partially filled in the gap by converting the silicon nitride film into the silicon oxide film
Implementation Method 2
partially filling each of the plurality of gaps with a flowable silicon nitride film
Data Source
AI summary
Disclosed is a substrate processing method comprising providing a substrate having a gap in a surface thereof into a reaction space, partially filling each of the plurality of gaps with a flowable silicon nitride film, forming a silicon oxide film partially filled in the gap by converting the silicon nitride film into the silicon oxide film, fully filling the gap, which is partially filled with the silicon oxide film, with a silicon nitride film, and forming a silicon oxide film to be fully filled in the gap, by converting the silicon nitride film into the silicon oxide film.