Etching Method Using Multivalent Hydrofluorocarbon Gas
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Solution Overview
Problem
Existing etching methods face challenges in maintaining uniformity of opening dimensions at the center and peripheral portions of patterns due to differences in active species and reaction product distribution, leading to circuit failures and shape inconsistencies in etched films.
Innovation Solution
An etching method using plasma generated from a gas mixture including hydrogen and a carbon and fluorine-containing gas with a multivalent hydrofluorocarbon, featuring a double bond of C and a CF3 group, which enhances mask selectivity and etch rate uniformity by promoting uniform deposition of reaction products on the mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used, then etching can be performed on laminated films, but shape differences occur in etched openings at center and peripheral portions due to non-uniform active species distribution
Solution Approach 1:
The patent changes the chemical parameters of the etching gas by introducing a multivalent hydrofluorocarbon gas with specific molecular structure (containing CF3 groups and unsaturated bonds). This parameter change in gas composition leads to uniform reaction product deposition on the mask, which in turn ensures uniform active species distribution and consistent etching rates across the substrate, eliminating shape differences in etched openings
Solution Approach 2:
The reaction products deposited on the mask surface act as an intermediary layer that mediates the etching process. The multivalent hydrofluorocarbon gas produces reaction products that uniformly deposit on the mask, creating a consistent intermediary layer that regulates active species generation and ensures uniform etching across the substrate, preventing circuit failures
2Manufacturing precision
If high mask selectivity is achieved, then etching precision is improved, but etch rate uniformity decreases due to reaction product deposition on mask
Solution Approach 1:
The patent optimizes the chemical composition parameters of the etching gas by using multivalent hydrofluorocarbon gas with specific molecular characteristics. This parameter change enables the reaction products to deposit uniformly on the mask surface, maintaining high mask selectivity while ensuring consistent etch rate across the substrate, thus resolving the trade-off between precision and productivity
3Manufacturing precision
If complex gas mixtures are used to improve etching uniformity, then manufacturing precision increases, but process complexity increases
Solution Approach 1:
Instead of using complex multi-component gas mixtures, the patent achieves etching uniformity by changing the molecular structure parameters of a single etching gas to multivalent hydrofluorocarbon. This parameter change in gas composition naturally produces uniform reaction product deposition and consistent active species distribution, simplifying the process while maintaining high manufacturing 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 effectively reduces shape differences in etched openings and achieves high mask selectivity, ensuring consistent etching depths and high throughput across dense and coarse patterns, even at high aspect ratios.
Implementation Method 1
etching the laminated films by plasma of a process gas including a carbon and fluorine-containing gas
Implementation Method 2
the carbon and fluorine-containing gas includes an unsaturated bond of C, and a CF3 group
Data Source
AI summary
An etching method prepares a substrate having laminated films including a first film and a second film that are alternately laminated, and a mask on the laminated films, and etches the laminated films by plasma of a process gas including a carbon and fluorine-containing gas. The carbon and fluorine-containing gas includes an unsaturated bond of C, and a CF3 group.