Doped Silicon Oxide Bottom-Up Gap Fill Without Sidewall Pinch-Off
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Solution Overview
Problem
As semiconductor feature sizes shrink, gap filling operations face challenges with deposition pinching off and forming voids or seams due to poor sidewall material quality, which affects device performance and requires frequent additional operations, introducing extra chemistries and reducing throughput.
Innovation Solution
A method involving sequential deposition and etch cycles using silicon-and-oxygen-containing materials with dopants, where plasma effluents are formed with specific precursors and frequencies to deposit doped silicon-and-oxygen-containing material, allowing selective removal of sidewall material to achieve bottom-up deposition without voids or seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to fill trenches, then material can be deposited on substrate surfaces, but deposition pinches off at sidewalls and produces voids within features
Solution Approach 1:
The deposition process is divided into multiple sequential cycles, each depositing a thin layer (e.g., 50-200 nm) followed by selective removal. This segmentation allows control over sidewall material quality while achieving complete gap filling, preventing void formation that occurs in single-step conventional deposition.
Solution Approach 2:
The patent employs periodic deposition and etch cycles to gradually fill trenches. Each cycle deposits material conformally on sidewalls and then selectively removes it, repeating this process until the trench is filled. This periodic action enables precise control of sidewall coverage while ensuring void-free filling.
2Quantity of substance
If deposition occurs at top and along sidewalls of features, then material forms on substrate, but continued deposition pinches off the feature and produces voids
Solution Approach 1:
The patent extracts or removes the problematic sidewall material after each deposition cycle using selective etching. This taking out action prevents the accumulation of poor-quality sidewall material that would otherwise pinch off features and create voids, while retaining the beneficial material deposited at the trench bottom.
Solution Approach 2:
The selective removal step is performed as a preliminary action before the next deposition cycle begins. This preliminary etching prevents sidewall material from interfering with subsequent deposition, ensuring that each new layer is deposited cleanly without causing pinch-off or void formation.
3Manufacturing precision
If selective removal of sidewall material is performed, then gap filling quality improves, but additional operations and chemistries are required
Solution Approach 1:
The patent uses a dopant-containing deposition precursor that serves multiple functions: it deposits the silicon-and-oxygen-containing material for gap filling while simultaneously doping the material to enable selective removal. This multi-functionality reduces the need for separate doping steps and simplifies the overall process chemistry.
Solution Approach 2:
The deposition and doping operations are merged into a single step by using dopant-containing precursors. This combining of operations reduces the total number of process steps and chemistries required, while still achieving the necessary sidewall material quality for selective removal and void-free filling.
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 enables controlled sidewall coverage and selective removal of sidewall material, ensuring seamless gap filling and improving device quality by repeating deposition and etch operations, maintaining high material quality and reducing operational complexity.
Implementation Method 1
forming plasma effluents of the one or more deposition precursors. The methods may include contacting the substrate with the plasma effluents of the one or more deposition precursors. The contacting may deposit a doped silicon-and-oxygen-containing material on the substrate
Implementation Method 2
forming plasma effluents of the one or more deposition precursors. The plasma effluents may be formed at a plasma frequency of less than or about 1,500 kHz
Implementation Method 3
Selectively removing the first portion of the doped silicon-and-oxygen-containing material may include contacting the substrate with a fluorine-containing precursor
Data Source
AI summary
Exemplary processing methods may include i) providing one or more deposition precursors to a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region. The substrate may include one or more features defining one or more sidewalls. The methods may include ii) forming plasma effluents of the one or more deposition precursors. The methods may include iii) contacting the substrate with the plasma effluents of the one or more deposition precursors. The contacting may deposit a doped silicon-and-oxygen-containing material on the substrate. A first portion of the doped silicon-and-oxygen-containing material deposited on the one or more sidewalls of the one or more features may be characterized by a poorer film quality than a second portion of the doped silicon-and-oxygen-containing material deposited on a lower portion of the one or more features.