Display Substrate Dual Insulation Mask Etching Control
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Solution Overview
Problem
The existing manufacturing methods for display substrates with polarization patterns face issues such as over-etching, non-uniformity due to inadequate photoresist thickness, and the formation of reaction products like titanium fluoride, which disrupt subsequent patterning processes, leading to defects and reduced productivity.
Innovation Solution
The use of a display substrate with a metal pattern, a first insulation pattern of silicon nitride or silicon oxide, and a second insulation pattern, where the first and second insulation layers are used as masks for etching, and the etching processes are monitored using carbon-nitride light intensity to prevent over-etching, and a metal layer with a titanium sub-layer to minimize reaction product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photoresist thickness is increased to prevent over-etching, then the mask protection is improved, but the photoresist pattern may generate slant and defects
Solution Approach 1:
The patent divides the single photoresist mask into two separate masks: a first photoresist mask for forming the first insulation pattern, and a second photoresist mask for forming the second insulation pattern. This segmentation allows each mask to be optimized independently, preventing the slant and defect issues that arise from using a single thick photoresist mask while still providing sufficient protection against over-etching.
Solution Approach 2:
The patent introduces a vertical layering dimension by forming the first insulation pattern and second insulation pattern at different levels. The first insulation pattern is formed at a first level and the second insulation pattern is formed at a second level, creating a stepped structure that eliminates the need for a single thick photoresist mask and prevents pattern slant.
2Productivity
If fluorine gas is used to etch the insulation layer and titanium layer, then the etching efficiency is improved, but titanium fluoride polymer reaction products are generated that disturb subsequent patterning
Solution Approach 1:
The patent extracts and removes the titanium layer that causes the harmful reaction. By removing the titanium layer before forming the insulation patterns, the source of titanium fluoride polymer formation is eliminated, allowing fluorine gas etching to proceed without generating disruptive reaction products.
Solution Approach 2:
The patent performs a preliminary removal of the titanium layer before subsequent etching processes. This preliminary action prevents the formation of titanium fluoride polymer reaction products during the insulation layer etching, ensuring clean patterning without disturbance from reaction byproducts.
3Device complexity
If a single insulation layer is used as mask, then the process complexity is reduced, but over-etching occurs that removes 30% more material than intended
Solution Approach 1:
The patent segments the single insulation mask into two separate insulation patterns formed at different levels. The first insulation pattern serves as the first mask and the second insulation pattern serves as the second mask. This segmentation provides better etching control and prevents over-etching while maintaining manageable process complexity.
Solution Approach 2:
The patent applies different properties to different parts of the insulation structure. The first insulation pattern has specific thickness and material properties optimized for protecting the underlying layer during first etching, while the second insulation pattern has different properties optimized for second etching. This local optimization improves etching precision without excessive complexity.
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 reduces defects and enhances productivity by preventing over-etching and minimizing reaction product interference, resulting in a more reliable and efficient display substrate manufacturing process.
Implementation Method 1
the insulation layer is etched by using a photoresist, such that the etched insulation layer may function as a hard mask in a subsequent process. The metal layer is etched by using the hard mask to manufacture the polarization layer including the polarization pattern.
Implementation Method 2
an etching process is performed, an over-etching may be generated where about 30% more of a thin layer is undesirably removed. Thus, an etching mask should have a sufficient thickness as a margin against the over-etching.
Data Source
AI summary
A display substrate includes a metal pattern, a first insulation layer pattern and a second insulation layer pattern. The metal pattern is on a base substrate. The first insulation pattern is on the metal pattern and includes one of a silicon nitride (SiNx) and a silicon oxide (SiOx). The second insulation pattern is on the first insulation pattern and includes a remaining one of the silicon nitride (SiNx) and the silicon oxide (SiOx).