Catalyst Chemical Etching with Zoned Actuation for Uniform Deep Features
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Solution Overview
Problem
Current Catalyst Influenced Chemical Etching (CICE) methods face limitations in fabricating features with high aspect ratios, low sidewall taper, and controllable porosity in semiconductors, leading to challenges in achieving uniform etch depth and preventing structural collapse.
Innovation Solution
A system with independently controlled discrete actuators and a method involving a catalyst layer with modified catalytic activity, optimized surface area exposure, and collapse-avoiding features to control etch depth and prevent structural collapse during CICE, using techniques like spin-spray etchant flow, thermal compensation, and electric field control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional CICE methods are used to fabricate high aspect ratio features, then porosity control and sidewall quality are improved, but etch depth uniformity deteriorates
Solution Approach 1:
The wafer surface is divided into multiple independently controllable zones with discrete actuators, allowing different etch conditions to be applied to different regions. This segmentation enables uniform etch depth control across the entire wafer while maintaining high aspect ratio feature quality in each zone.
Solution Approach 2:
Different regions of the wafer are provided with locally optimized etch conditions through independently controlled actuators. Each zone can have tailored parameters for catalyst activity, etchant flow rate, and temperature, ensuring both uniform depth and high sidewall quality in each local region.
2Productivity
If conventional CICE methods are used to create high aspect ratio structures, then feature density is improved, but structural collapse increases
Solution Approach 1:
Support structures are deposited on the wafer surface before the CICE process to provide mechanical reinforcement during etching. These preliminary structural elements prevent collapse of high aspect ratio features while allowing dense feature patterns to be formed.
Solution Approach 2:
The structure combines the semiconductor material being etched with deposited support materials to create a composite structure. The support material provides mechanical strength to prevent collapse, while the semiconductor material forms the functional high-density features.
3Manufacturing precision
If uniform etch depth is achieved across the substrate, then manufacturing precision is improved, but device pattern versatility deteriorates
Solution Approach 1:
The etch system dynamically adjusts parameters for each zone based on real-time feedback and pattern requirements. The independently controlled actuators can modify etch conditions during the process to achieve uniform depth while accommodating different device patterns in different regions.
Solution Approach 2:
Different etch parameters (catalyst activity, temperature, etchant concentration) are applied to different zones to achieve uniform etch depth across the wafer while maintaining the ability to create diverse device patterns. Each pattern type can be optimized with specific parameter sets.
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 solution enables precise control of etch depth with variations less than 10% of feature height, prevents substantial collapse of high aspect ratio structures, and achieves tunable etch depth for micro- or nanostructures, improving the fabrication of semiconductor features with enhanced performance and density.
Implementation Method 1
Catalyst Influenced Chemical Etching (CICE), which is a catalyst-based etching method
Implementation Method 2
spin-spray etchant flow
Data Source
AI summary
A method and system for etching a semiconductor substrate using catalyst influenced chemical etching. A group of independently controlled discrete actuators are configured to control a depth of an etch of a material on a substrate, where at least two of the group of independently controlled discrete actuators has distinct actuation values. Furthermore, the etch depth has a variation of less than 10% of a feature height across the substrate.