Oxygen-Containing Hydrofluorocarbon Plasma Etching for Profile Control
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Solution Overview
Problem
Current plasma etching methods face challenges in achieving high selectivity to masks and precise control over the shape of high aspect ratio structures during the etching of silicon-containing films, particularly in 3D semiconductor fabrication, where maintaining high etch rates while preventing profile distortions and lateral etching is crucial.
Innovation Solution
The use of oxygen-containing hydrofluorocarbons with specific formulas, such as CxHyFzOn, where 2≤x≤13, 1≤y≤15, 1≤z≤21, and 1≤n≤3, incorporated into the plasma etching process, which includes at least one oxygen atom in an ether or carbonyl group, to enhance etch rates and selectivity by generating specific reactive species that promote anisotropic etching and reduce lateral etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching methods are used to etch silicon-containing films, then etching can proceed, but selectivity to mask material deteriorates and profile control becomes poor
Solution Approach 1:
The patent changes the chemical composition parameters of the etching gas by using oxygen-containing hydrofluorocarbons with specific formulas CxHyFzOn where 2≤x≤10, 1≤y≤15, 1≤z≤21, and 1≤n≤3. This chemical parameter change improves both selectivity to mask material and profile control simultaneously, resolving the technical contradiction between manufacturing precision and reliability.
Solution Approach 2:
The patent employs composite etching chemistry by incorporating oxygen atoms into hydrofluorocarbon molecules to create oxygen-containing hydrofluorocarbons. This composite molecular structure enables the gas to provide both high selectivity to mask material and precise profile control, addressing the contradiction between reliability and manufacturing precision.
2Productivity
If high etch rates are achieved in silicon-containing films, then productivity increases, but lateral etching increases and profile distortion occurs
Solution Approach 1:
The patent modifies the etching gas composition by using oxygen-containing hydrofluorocarbons with specific molecular formulas. This parameter change enables the process to achieve high etch rates for SiO2 and SiN while simultaneously maintaining precise profile control and minimizing lateral etching, thus resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The oxygen-containing hydrofluorocarbon provides different reactive properties at different locations: high reactivity with silicon-containing films for fast etching, and controlled reactivity with mask material and sidewalls for profile control. This local quality differentiation resolves the contradiction between high etch rate and profile precision.
3Reliability
If molecular oxygen is used to control etching, then selectivity improves, but polymer film deposition control deteriorates
Solution Approach 1:
The patent replaces molecular oxygen with oxygen-containing hydrofluorocarbon compounds. This composite molecular structure provides both the oxygen reactivity needed for selectivity and the hydrofluorocarbon backbone needed for polymer film deposition control, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent merges the functions of oxygen (for selectivity) and hydrofluorocarbon (for polymer control) into a single oxygen-containing hydrofluorocarbon molecule. This merging eliminates the need to balance two separate gases and simultaneously provides both selectivity and polymer film profile control.
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 significantly increases etch rates of SiO2 and SiN materials, improves selectivity to mask materials, and maintains precise control over the etched structure profiles, even at high aspect ratios, reducing the need for molecular oxygen and minimizing sidewall damage.
Implementation Method 1
converting the etching gas to a plasma
Implementation Method 2
converting the etching gas to a plasma
Implementation Method 3
allowing an etching reaction to proceed between the plasma and the one or more silicon-containing films
Data Source
AI summary
An etching method for forming an aperture by selectively etching one or more silicon-containing films in a substrate using a patterned mask layer deposited on top of the one or more silicon-containing films comprises: mounting the substrate in a processing chamber; introducing an etching gas containing a vapor of an oxygen-containing hydrofluorocarbon into the processing chamber; converting the etching gas to a plasma; and allowing an etching reaction to proceed between the plasma and the one or more silicon-containing films so that the one or more silicon-containing films are selectively etched versus the patterned mask layer to form the aperture, wherein the oxygen-containing hydrofluorocarbon has a general formula CxHyFzOn, where 2≤x≤13, 1≤y≤15, 1≤z≤21, 1≤n≤3.