Tin Oxide Film Etching With Sidewall Passivation Control
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Solution Overview
Problem
Current semiconductor manufacturing methods face challenges in precisely patterning small-scale features using spacers, as existing techniques lack effective selectivity and control in etching tin oxide films, leading to inconsistencies and material loss during the process.
Innovation Solution
A method involving the deposition of a tin oxide layer on semiconductor substrates, followed by the formation of a passivation layer on sidewalls, and selective etching of the tin oxide from horizontal surfaces using hydrogen or chlorine-based chemistries, allowing for the preservation of tin oxide spacers while exposing underlying materials, thereby enhancing etch selectivity and reducing material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional etching techniques are used to remove tin oxide from horizontal surfaces, then material removal is achieved, but etch selectivity is insufficient leading to tin oxide loss from sidewalls
Solution Approach 1:
The patent applies different protective measures to different locations: a passivation layer is deposited only on sidewalls (not on horizontal surfaces) to protect tin oxide from etching. This local differentiation allows selective removal of tin oxide from horizontal surfaces while preserving it on sidewalls, directly resolving the etch selectivity problem.
Solution Approach 2:
The passivation layer is deposited on sidewalls before the etching process begins. This preliminary protective action ensures that when etching occurs, the sidewall tin oxide is already protected, preventing material loss and ensuring high etch selectivity during the subsequent etching step.
2Manufacturing precision
If spacers are removed after patterning, then the patterning process is completed, but precise control of critical dimensions is difficult to achieve
Solution Approach 1:
The patent creates local quality differences by selectively removing tin oxide from horizontal surfaces while preserving it on sidewalls. This results in tin oxide spacers that remain on sidewalls after the patterning process, providing precise critical dimension control without requiring complete spacer removal.
Solution Approach 2:
The tin oxide layer serves as an intermediary material that enables precise patterning. By selectively removing it from horizontal surfaces while keeping it on sidewalls, it acts as a mediator that defines critical dimensions accurately while simplifying the overall manufacturing process.
3Manufacturing precision
If tin oxide is completely removed from protruding features, then the underlying material is exposed, but footing formation occurs reducing pattern consistency
Solution Approach 1:
The patent applies selective protection to sidewalls through passivation layer deposition, preventing tin oxide removal in these regions. This local quality differentiation eliminates footing formation at the base of patterns while still exposing the underlying material on horizontal surfaces, thereby maintaining pattern consistency.
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 precise patterning with high etch selectivity, minimizing material loss and maintaining tin oxide spacers, which is crucial for achieving consistent critical dimensions and reducing footing in semiconductor devices.
Implementation Method 1
etching the tin oxide using a hydrogen-based etch chemistry that results in a formation of a tin hydride
Implementation Method 2
contacting the semiconductor substrate with a plasma-activated hydrogen-containing reactant
Implementation Method 3
etching the tin oxide using a chlorine-based etch chemistry that comprises exposing the semiconductor substrate to a plasma-activated chlorine-containing reactant
Data Source
AI summary
Tin oxide film on a semiconductor substrate is etched selectively with an etch selectivity of at least 10 in a presence of silicon (Si), carbon (C), or a carbon-containing material (e.g., photoresist) by exposing the substrate to a process gas comprising hydrogen (H2) and a hydrocarbon (e.g., at a hydrogen/hydrocarbon ratio of at least 5), such that a carbon-containing polymer is formed on the substrate. In some embodiments an apparatus for processing a semiconductor substrate includes a process chamber configured for housing the semiconductor substrate and a controller having program instructions on a non-transitory medium for causing selective etching of a tin oxide layer on a substrate in a presence of silicon, carbon, or a carbon-containing material by exposing the substrate to a plasma formed in a process gas that includes H2 and a hydrocarbon.