Semiconductor Opening Sidewall Protection via Bromide Sublimation
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Solution Overview
Problem
Conventional semiconductor fabrication methods face challenges in forming high aspect ratio openings with minimal damage during the removal of mask layers, leading to reduced elemental performance and increased complexity as feature sizes decrease.
Innovation Solution
A method using a silicon-containing mask layer that employs a bromine covering process to form a bromide layer, followed by a bromide sublimation process for peeling removal, protecting the sidewalls and avoiding over-etching, thereby simplifying the process and improving the structure of semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mask layer removal methods are used, then the mask layer can be removed, but the openings are damaged and over-etched
Solution Approach 1:
A silicon-containing mask layer is introduced as an intermediary between the photoresist pattern and the stacked structure. This silicon mask layer serves as a protective intermediary that prevents direct damage to the openings during photoresist removal, while still allowing precise pattern transfer and controlled etching of the underlying structure.
Solution Approach 2:
The silicon-containing mask layer is formed preliminarily before the etching process to establish a protective barrier. This preliminary action ensures that the openings are protected from damage during subsequent photoresist removal and etching operations, maintaining opening integrity while enabling effective mask layer removal.
2Productivity
If feature sizes are decreased, then circuit complexity is reduced, but fabrication process becomes more difficult
Solution Approach 1:
The fabrication process is segmented into distinct stages with the silicon-containing mask layer serving as a separate functional layer. This segmentation allows the photoresist pattern transfer and the actual etching to be decoupled, enabling precise control at each stage and simplifying the overall fabrication process for small features.
Solution Approach 2:
The introduction of the silicon-containing mask layer changes the material parameters of the masking system. This parameter change enables better control over etching selectivity and pattern fidelity, making it easier to fabricate small features while maintaining process simplicity.
3Productivity
If mask layer is removed aggressively, then removal efficiency is improved, but opening sidewalls are damaged
Solution Approach 1:
The silicon-containing mask layer acts as a sacrificial intermediary that absorbs the mechanical and chemical stress during removal. This intermediary layer can be removed efficiently through chemical means (such as HF vapor or liquid) without transmitting damaging forces to the opening sidewalls, thus maintaining both removal efficiency and sidewall integrity.
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 effectively removes the silicon-containing mask layer without damaging the openings, maintaining vertical sidewalls and enhancing the performance and structure of semiconductor devices by reducing defects and preserving the integrity of the semiconductor device features.
Implementation Method 1
a bromine covering process is performed, to from a bromide layer on surfaces of the patterned silicon-containing mask layer
Implementation Method 2
a bromide sublimation process is performed, to completely remove the bromide layer
Data Source
AI summary
A method of forming a semiconductor device includes following steps. First of all, a substrate is provided, and a stacked structure is formed on the substrate. Then, a patterned silicon-containing mask layer is formed on the stacked structure, and the stacked structure is partially removed through the patterned silicon-containing mask layer, to form plural openings in the stacked structure. Following these, a bromine covering process is performed, to form a bromide layer on a portion of the patterned silicon-containing mask layer, and a bromide sublimation process is then performed, to completely remove the bromide layer.