Nitrogen Etching Gas Composition for Selective Silicon Hole Profiles
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Solution Overview
Problem
The challenge in manufacturing integrated circuit (IC) devices is to achieve a desired vertical profile and etch rate while maintaining high etch selectivity and control over critical dimensions (CD) during the plasma etching process for forming vertical holes with high aspect ratios.
Innovation Solution
An etching gas mixture comprising a nitrogen-containing compound, such as those represented by Formulas 1 and 2, and an inert gas, optionally combined with fluorine-containing, oxygen-containing gases, or C1 to C4 fluorinated hydrocarbons, is used to ensure a stable plasma and high etch selectivity during the plasma etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching gas mixtures are used to etch silicon-containing films, then etching can proceed, but the etch selectivity with respect to carbon-containing etch masks is insufficient and vertical profiles are not well-maintained
Solution Approach 1:
The patent changes the chemical composition parameters of the etching gas mixture by incorporating specific nitrogen-containing compounds (nitriles and isocyanides with perfluoroalkyl groups) in controlled concentrations (0.1-10% by volume). This parameter change transforms the etching chemistry to achieve high selectivity for silicon-containing films while maintaining vertical profiles and minimizing polymer byproduct formation on carbon-containing masks.
Solution Approach 2:
The patent creates a composite etching gas mixture combining nitrogen-containing compounds (nitriles/isocyanides), fluorinated compounds, and inert gases. This composite formulation synergistically achieves: (1) high etch selectivity for silicon-containing films, (2) maintained vertical profiles, (3) reduced polymer byproducts, and (4) stable plasma generation, resolving the technical contradictions present in conventional single-component or simpler mixture approaches.
2Shape
If plasma etching is performed to form vertical holes with high aspect ratios, then the holes can be formed, but achieving desired vertical profile and etch rate simultaneously is difficult
Solution Approach 1:
The patent optimizes the concentration parameters of nitrogen-containing compounds (0.1-10% by volume) and fluorinated compounds in the etching gas mixture. This parameter optimization enables the plasma to achieve both vertical anisotropic etching profiles and high etch rates by balancing the chemistry between silicon film removal and side-wall protection, resolving the trade-off between profile quality and productivity.
Solution Approach 2:
The nitrogen-containing compounds (nitriles and isocyanides) act as intermediary species in the plasma chemistry. They mediate between the fluorinated etching species and the silicon-containing film, enabling controlled anisotropic etching that maintains vertical profiles while achieving high etch rates through stable plasma generation and selective chemical reactions.
3Manufacturing precision
If critical dimension control is needed during etching, then precise control is required, but maintaining desired CD while achieving high etch rate and vertical profile is challenging
Solution Approach 1:
The patent precisely controls the concentration parameters of nitrogen-containing compounds (0.1-10% by volume) and fluorinated compounds in the etching gas mixture. This precise parameter control enables independent optimization of CD control and etch rate by adjusting the relative proportions of different gas components, allowing simultaneous achievement of high manufacturing precision and productivity.
Solution Approach 2:
The etching gas mixture composition acts as a feedback mechanism for controlling etch kinetics. The nitrogen-containing compounds modulate the plasma chemistry to provide self-regulating etch rates that maintain consistent CD control while achieving high productivity, as the chemical composition automatically balances film removal with side-wall protection and polymer byproduct formation.
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 proposed etching gas mixture effectively achieves a desired vertical profile, etch rate, and high etch selectivity, improving the reliability and productivity of IC device manufacturing by reducing polymer byproducts and enhancing CD control.
Implementation Method 1
when a plasma etching process is performed to form a vertical hole having a relatively high aspect ratio
Implementation Method 2
an etching gas mixture for selectively etching a silicon-containing film
Data Source
AI summary
An etching gas mixture includes a nitrogen-containing compound and an inert gas. To manufacture an integrated circuit (IC) device, a silicon-containing film on a substrate is etched by using plasma generated from the etching gas mixture, and thus a hole is formed in the silicon-containing film. The nitrogen-containing compound is selected from a compound represented by Formula 1 and a compound represented by Formula 2:(R1)C≡N [Formula 1]wherein in Formula 1, R1 is a C2 to C3 linear or branched perfluoroalkyl group,(R2)(R3)C═NH [Formula 2]wherein in Formula 2, each of R2 and R3 is independently a C1 to C2 linear perfluoroalkyl group.