Gap Filling Fluid Deposition for High Aspect Ratio Trenches
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Solution Overview
Problem
Conventional plasma-enhanced chemical vapor deposition methods fail to effectively fill high aspect ratio gaps in semiconductor fabrication due to the formation of voids and seams, particularly in narrow trenches, leading to structure failure.
Innovation Solution
A method involving a cyclical deposition process using a silicon precursor and a noble gas reactant in a plasma-assisted reaction chamber, where the precursor and plasma pulses are separated and react to form a gap filling fluid comprising silicon and hydrogen, which fills the gaps without voids or seams, and is followed by a curing step to enhance the film's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional PECVD is used to deposit amorphous silicon, then the deposition process is simple and fast, but the plasma cannot penetrate into deep trenches resulting in mushroom shape film and void formation
Solution Approach 1:
The deposition process is divided into multiple sequential half-cycles, with precursor exposure and plasma activation separated in time. This segmentation allows the precursor to penetrate deep into trenches first, then activates uniformly without causing mushroom shaping, thereby improving gap filling quality while managing process complexity through structured sequencing
Solution Approach 2:
The patent employs periodic alternating exposure to precursor and plasma in half-cycles, creating a rhythmic deposition pattern. This periodic action enables controlled material accumulation that fills high aspect ratio gaps uniformly without void formation, achieving precise manufacturing control through time-periodic process modulation
2Reliability
If furnace poly-silicon or amorphous silicon dummy gate is used in metal replacement gate process, then the process is conventional and simple, but a seam forms in the middle of the dummy gate causing structure failure
Solution Approach 1:
The dummy gate deposition is segmented into multiple half-cycles with alternating precursor and plasma exposure. This segmentation eliminates the central seam formation by ensuring uniform material distribution throughout the deposition process, thereby improving structural integrity while maintaining manufacturability through a controlled sequential process
Solution Approach 2:
The multi-half-cycle deposition process maintains continuous material accumulation without interruption or seam formation. The continuous uniform deposition action ensures complete coverage and structural integrity of the dummy gate, improving reliability while the process remains manufacturable through systematic sequential steps
3Productivity
If plasma is continuously generated during deposition, then the deposition rate is high, but the plasma cannot penetrate into narrow trenches effectively
Solution Approach 1:
The continuous plasma generation is segmented into discrete plasma half-cycles separated by precursor exposure half-cycles. This segmentation allows precursor penetration into narrow trenches during non-plasma periods, then activates uniformly during plasma periods, achieving both effective trench filling and maintained deposition rate through time-separated actions
Solution Approach 2:
The deposition process uses periodic alternation between precursor exposure and plasma activation in half-cycles. This periodic action enables effective plasma penetration into narrow trenches by resetting plasma conditions each cycle, maintaining high productivity through rhythmic deposition while ensuring uniform trench filling 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 ensures seamless filling of high aspect ratio gaps with a viscous material that extends into the gap up to several times its width, preventing voids and seams, and the curing step improves the thermal resistance and stability of the deposited film.
Implementation Method 1
generating a plasma in the reaction chamber and introducing a reactant into the reaction chamber. The reactant comprises a noble gas. The gap filling fluid comprises silicon and hydrogen. The silicon precursor and the reactant react in the presence of the plasma to form a gap filling fluid
Implementation Method 2
depositing a gap filling fluid by executing a cyclical deposition process. The cyclical deposition process comprises a plurality of deposition cycles. A deposition cycle comprises a precursor pulse and a plasma pulse
Data Source
AI summary
Methods and systems for manufacturing a structure comprising a substrate. The substrate comprises plurality of recesses. The recesses are at least partially filled with a gap filling fluid. The gap filling fluid comprises a Si—H bond.