Amorphous Carbon Mask Trench Etching Selectivity
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Solution Overview
Problem
Existing methods for forming trenches in thin film transistor array panels suffer from low etching selectivity and contamination of the trench interior due to the use of photosensitive films or metal masks, which result in residual films and poor trench integrity.
Innovation Solution
A trench forming method using an amorphous carbon layer as a mask, where a first insulating layer is etched using a fluorine-based primary etching gas, and the amorphous carbon layer is etched using an oxygen-based gas, reducing contamination and improving selectivity by preventing metallic foreign substances from entering the trench.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photosensitive film is used as a mask for etching, then the trench can be formed, but the etching selectivity is very low and residual films remain
Solution Approach 1:
The patent changes the material parameter of the mask from photosensitive film to amorphous carbon layer, which has different etching characteristics. The amorphous carbon layer provides high etching selectivity against the insulating layer while maintaining good trench formation quality, resolving the contradiction between manufacturing precision and etching selectivity.
2Reliability
If a metal mask is used for etching, then the etching selectivity is improved, but residue is produced in the trench and the bottom cannot be etched
Solution Approach 1:
The patent uses an amorphous carbon layer as a disposable mask that can be completely removed after etching. This mask material provides high selectivity during etching like metal masks but does not leave residual contamination in the trench, as it can be cleanly removed by oxygen plasma treatment, resolving the contradiction between etching selectivity and trench cleanliness.
3Manufacturing precision
If existing mask materials are used, then the trench can be formed, but metallic foreign substances contaminate the trench interior
Solution Approach 1:
The patent introduces an amorphous carbon layer as an intermediary mask material between the traditional metal mask and the photosensitive film. This intermediary material provides the structural integrity needed for precise trench formation while being chemically inert and removable without leaving metallic contamination, thus resolving the contradiction between trench formation quality and contamination prevention.
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 method enhances etching selectivity and prevents trench contamination, allowing for the formation of high-quality metal wiring and reducing residual films, thereby improving the integrity and performance of thin film transistor array panels.
Implementation Method 1
etching the first insulating layer using the amorphous carbon layer including the opening as a mask
Implementation Method 2
the amorphous carbon layer is etched using an oxygen-based gas
Data Source
AI summary
A method of forming a thin film transistor array panel includes: forming a first insulating layer on a substrate; forming an amorphous carbon layer on the first insulating layer; forming a second insulating layer on the amorphous carbon layer; forming an opening in the amorphous carbon layer by patterning the second insulating layer and the amorphous carbon layer; and forming a trench in the first insulating layer by etching the first insulating layer, the etching the first insulating layer using the amorphous carbon layer including the opening as a mask.