Directional Silicon Gap Fill to Prevent Voids in Narrow Features
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Solution Overview
Problem
Conventional gap filling operations in semiconductor manufacturing face challenges with void and seam formation in narrow features with high aspect ratios, leading to device performance issues and subsequent processing complications.
Innovation Solution
A method involving sequential deposition and etching of silicon-and-carbon-containing materials, using plasma effluents of silicon-, carbon-, hydrogen-, and nitrogen-containing precursors, with controlled bias power and pulsing modes, to fill and densify features while limiting sidewall coverage and incorporating nitrogen doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition is used to fill narrow features, then material can be deposited to fill the feature, but voids and seams form within the feature due to pinch-off at the top and sidewalls
Solution Approach 1:
The patent applies periodic action by alternating between deposition and etching operations in cyclic fashion. The deposition step fills the feature while the etching step removes material from sidewalls that would otherwise cause pinch-off and void formation. This periodic alternation enables continuous filling without defect formation.
Solution Approach 2:
The patent segments the gap fill process into distinct deposition and etching steps rather than using continuous deposition. Each cycle consists of a deposition phase followed by an etching phase, allowing the process to address both filling and defect prevention in a segmented manner.
2Quantity of substance
If deposition occurs at the top and along sidewalls of the feature, then material fills the feature, but the feature pinches off between sidewalls producing voids
Solution Approach 1:
The patent extracts harmful sidewall deposits by introducing an etching step that selectively removes material from the sidewalls after deposition. This extraction prevents the sidewall buildup that causes feature pinch-off and maintains proper feature geometry throughout the filling process.
Solution Approach 2:
The patent uses periodic alternation between deposition and etching to control material distribution. During deposition, material is deposited everywhere including sidewalls; during the subsequent etching phase, sidewall material is selectively removed. This periodic cycle prevents permanent sidewall buildup and pinch-off.
3Manufacturing precision
If sequential deposition and etching is used to prevent voids, then seam-free fill is achieved, but process complexity increases with multiple precursor deliveries and plasma formations
Solution Approach 1:
The patent applies multi-functionality by using the same processing chamber and plasma generation system for both deposition and etching operations. The system transitions between modes rather than requiring separate equipment, reducing overall process complexity while achieving seam-free fill.
Solution Approach 2:
The patent combines deposition and etching operations into a single integrated process sequence within one chamber. Rather than separate processes, the deposition and etching steps are merged into alternating cycles, simplifying the overall manufacturing workflow while maintaining high precision.
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 effectively prevents seam and void formation, providing a densified, seam-free fill in narrow features with improved device performance and structural integrity.
Implementation Method 1
forming plasma effluents of the silicon-containing precursor and the carbon-containing precursor... depositing a silicon-and-carbon-containing material on the substrate
Implementation Method 2
etching the silicon-and-carbon-containing material from a sidewall of the feature within the substrate with the plasma effluents of the hydrogen-containing precursor
Implementation Method 3
doping the silicon-and-carbon-containing material with nitrogen from the plasma effluents of the nitrogen-containing precursor
Data Source
AI summary
Exemplary processing methods may include providing a silicon-containing precursor and a carbon-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be housed in the processing region. The substrate may define a feature within the substrate. The methods may include forming plasma effluents of the silicon-containing precursor and the carbon-containing precursor. The methods may include depositing a silicon-and-carbon-containing material on the substrate. The methods may include providing a hydrogen-containing precursor to the processing region of the semiconductor processing chamber, forming plasma effluents of the hydrogen-containing precursor, and etching the silicon-and-carbon-containing material from a sidewall of the feature within the substrate. The methods may include providing a nitrogen-containing precursor to the processing region of the semiconductor processing chamber, forming plasma effluents of the nitrogen-containing precursor, and doping the silicon-and-carbon-containing material with nitrogen.