Dry Etching Method for Silicon Layers
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Solution Overview
Problem
In the manufacturing of three-dimensional structural semiconductor elements, there is a tendency for non-uniformity in etching depth within holes or grooves due to the varying depths of specific silicon layers, leading to performance deterioration.
Innovation Solution
A dry etching method using a mixed gas containing F2 and at least one interhalogen gas selected from ClF3, BrF5, BrF3, IF7, and IF5, with specific partial pressures and optional diluent gases like N2, He, or Ar, to ensure uniform etching depth across the silicon layers on inner surfaces of holes or grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dry etching methods using ClF3 or XeF2 gas are used to etch silicon layers in holes or grooves, then the etching process can be performed, but non-uniformity in etching depth occurs due to varying depths of specific silicon layers
Solution Approach 1:
The patent applies parameter changes by modifying the etching gas composition from conventional single-gas systems (ClF3 or XeF2) to a mixed gas system containing F2 and at least one interhalogen gas (ClF3, BrF5, BrF3, IF7, or IF5). This chemical parameter change enables uniform etching depth across silicon layers at varying depths within holes or grooves, resolving the etching depth uniformity issue while maintaining device performance
Solution Approach 2:
The patent uses a composite etching gas mixture combining F2 with interhalogen gases (ClF3, BrF5, BrF3, IF7, or IF5) in specific partial pressure ratios. This composite gas system provides synergistic effects that achieve uniform etching depth across different silicon layer depths, preventing the non-uniformity that occurs with conventional single-gas etching methods
2Productivity
If fine processing techniques are used to reduce circuit line widths for high integration, then the number of semiconductor elements per unit area increases, but malfunctions increase
Solution Approach 1:
The patent changes the etching process parameters by using a mixed gas system with F2 and interhalogen gases, which provides uniform etching depth control in three-dimensional structures. This enables reliable fine processing of silicon layers in high-density integrated circuits, reducing malfunctions that occur with conventional etching methods
3Productivity
If three-dimensional structural elements are formed with holes or grooves to increase integration, then device capacity increases, but non-uniformity in etching depth of specific layers occurs
Solution Approach 1:
The patent employs a composite etching gas mixture of F2 and interhalogen gases (ClF3, BrF5, BrF3, IF7, or IF5) in specific partial pressure ratios. This composite system achieves uniform etching depth across silicon layers at different positions within three-dimensional holes or grooves, enabling high device capacity while maintaining manufacturing precision
Solution Approach 2:
The patent modifies the etching gas composition parameters to include F2 combined with interhalogen gases, which provides uniform etching depth control throughout the depth of holes or grooves in three-dimensional structures, preventing non-uniformity while maintaining high device capacity
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 prevents non-uniformity of etching depth, enhancing the uniformity and performance of semiconductor devices by maintaining consistent etching depth across the silicon layers.
Implementation Method 1
a dry etching method using a mixed gas containing F2 and at least one interhalogen gas selected from ClF3, BrF5, BrF3, IF7, and IF5, with specific partial pressures and optional diluent gases like N2, He, or Ar, to ensure uniform etching depth across the silicon layers on inner surfaces of holes or grooves
Data Source
AI summary
There is provided according to the present invention a dry etching method for a laminated film, the laminated film being formed on a substrate and having a laminated structure in which silicon layers and insulating layers are laminated together with a hole or groove defined therein in a direction perpendicular to a surface of the substrate, the dry etching method comprising etching, with an etching gas, parts of the silicon layers appearing on an inner surface of the hole or groove, characterized in that the etching gas comprises: at least one kind of gas selected from the group consisting of ClF3, BrF5, BrF3, IF7 and IF5; and F2. It is possible by such a dry etching method to prevent non-uniformity of etching depth between the silicon layers.