Directional Plasma Deposition for Void-Free Feature Fill
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Solution Overview
Problem
Conventional methods face challenges in filling narrow features with high aspect ratios in semiconductor manufacturing, leading to voids and pinching off due to deposition on sidewalls, which affects device performance and subsequent processing operations.
Innovation Solution
A method involving the formation of a plasma of a silicon-containing precursor, followed by a hydrogen-containing precursor to etch and densify the flowable film within the feature, using pulsed bias and source powers to selectively remove sidewall material and maintain denser material at the bottom, and optionally converting the film to silicon nitride, silicon oxide, or silicon carbide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deposition is performed to fill narrow features with high aspect ratios, then the feature may be filled with material, but deposition occurs at the top and along sidewalls causing pinching off and void formation
Solution Approach 1:
The patent applies periodic pulsed power delivery to the substrate during deposition, alternating between high power pulses that enhance directional transport and fill the feature bottom, and low power intervals that reduce sidewall deposition. This temporal modulation of deposition conditions enables selective filling of high aspect ratio features while preventing pinching off and void formation that would occur with continuous deposition
Solution Approach 2:
The patent dynamically adjusts deposition parameters including pulsed power levels, gas flow rates, and substrate temperature during the deposition process. By making the deposition system dynamic rather than static, the process can adapt to changing film thickness and feature filling states, optimizing material transport directionality to prevent sidewall pinching while ensuring complete feature filling
2Quantity of substance
If conventional deposition methods are used for gap filling, then material is deposited to fill the trench, but continued deposition pinches off the feature between sidewalls
Solution Approach 1:
Pulsed power delivery creates periodic variations in plasma density and ion flux that enhance directional transport during high power phases, promoting vertical material transport into the trench. During low power phases, reduced sidewall deposition allows the feature geometry to be maintained. This periodic modulation enables continuous material fill while preventing the pinching off that would occur with conventional continuous deposition
Solution Approach 2:
The patent changes key deposition parameters including power level, gas flow rate, and pressure during the deposition process. By dynamically adjusting these parameters, the process transitions between regimes that favor vertical transport (filling the trench) and regimes that reduce lateral deposition (preventing pinching), thereby achieving complete fill while maintaining feature geometry
3Productivity
If deposition occurs at high power levels, then faster film formation is achieved, but increased deposition on sidewalls causes pinching off
Solution Approach 1:
The patent employs periodic pulsed power delivery where high power phases drive rapid material deposition and enhance directional transport into the feature, while low power phases reduce sidewall deposition rates. This temporal separation allows high overall productivity through accumulation of fast deposition phases while preventing pinching during low power intervals when sidewall deposition is suppressed
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
Improves the quality of material within features by selectively etching sidewall coverage, preventing voids and enhancing fill operations, while maintaining denser material at the bottom, thus improving device performance and reducing film restrictions.
Implementation Method 1
forming a plasma of a silicon-containing precursor. The plasma of the silicon-containing precursor may be formed at a first power level from a plasma power source
Implementation Method 2
depositing a flowable film on a semiconductor substrate with plasma effluents of the silicon-containing precursor
Implementation Method 3
etching and/or modifying the flowable film from a sidewall of the feature within the semiconductor substrate with plasma effluents of the hydrogen-containing precursor
Implementation Method 4
forming a plasma of a hydrogen-containing precursor within the processing region of the semiconductor processing chamber. The plasma of the hydrogen-containing precursor may be formed at a second power level
Data Source
AI summary
Exemplary processing methods may include forming a plasma of a silicon-containing precursor. The methods may include depositing a flowable film on a semiconductor substrate with plasma effluents of the silicon-containing precursor. The processing region may be at least partially defined between a faceplate and a substrate support on which the semiconductor substrate is seated. A bias power may be applied to the substrate support from a bias power source. The methods may include forming a plasma of a hydrogen-containing precursor within the processing region of the semiconductor processing chamber. The methods may include etching the flowable film from a sidewall of the feature within the semiconductor substrate with plasma effluents of the hydrogen-containing precursor. The methods may include densifying remaining flowable film within the feature defined within the semiconductor substrate with plasma effluents of the hydrogen-containing precursor.