Display Substrate Multi-Step Etching to Remove Polymer Fence
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Solution Overview
Problem
The existing display substrate manufacturing process often results in contact failures between the drain electrode and the pixel electrode due to the formation of a metallic polymer fence on the sidewall of the contact hole, which affects the reliability of the display device.
Innovation Solution
A display substrate is designed with a multi-step etching process using different insulating materials and etching rates to form contact holes, where the upper and lower second insulation layers have specific hole configurations and inclination angles, and the etching processes include anisotropic and isotropic etching to expose the drain and common electrodes, respectively, while removing the fence formed during the initial etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single etching process is used to form contact holes, then the manufacturing process is simple, but the metallic polymer fence remains on the sidewall causing contact failure
Solution Approach 1:
The etching process is divided into multiple sequential steps: first etching to form initial contact holes, then second etching to remove the metallic polymer fence and expand the contact holes. This segmentation allows each etching step to serve a specific purpose, ensuring reliable electrical contact while maintaining process control.
Solution Approach 2:
The first etching process performs preliminary action by forming initial contact holes and exposing the drain electrode before the second etching process removes the metallic polymer fence. This preliminary action sets up the structure for subsequent fence removal and contact hole expansion.
2Reliability
If the contact hole is formed directly without multi-step etching, then the manufacturing process is fast, but the fence causes contact failure between drain electrode and pixel electrode
Solution Approach 1:
The contact hole formation is segmented into two distinct etching processes with different objectives. The first process creates the initial opening and exposes the drain electrode, while the second process removes the metallic polymer fence and enlarges the contact hole. This segmentation ensures reliable electrical connection by eliminating the fence obstacle.
Solution Approach 2:
The two etching processes are performed in continuous sequence without interrupting the manufacturing flow. The first etching continuously removes insulation layer to form contact holes, and the second etching continuously removes the metallic polymer fence and expands the holes, maintaining productive action throughout both steps.
3Reliability
If the sidewall of contact hole is vertical, then the contact hole shape is simple, but the metallic polymer fence blocks the contact between electrodes
Solution Approach 1:
The contact hole structure is segmented into multiple regions: the upper portion formed by first etching with vertical sidewalls, and the lower portion expanded by second etching that removes the metallic polymer fence. This segmentation allows the contact hole to have different shape characteristics in different regions, ensuring reliable electrical contact while maintaining manufacturing simplicity.
Solution Approach 2:
The contact hole structure transitions from a simple vertical cylindrical shape to a more complex geometry with expanded lower portion. The second etching process adds dimensional complexity by enlarging the contact hole width at the lower region, allowing the electrode contact area to increase and bypass the metallic polymer fence obstruction.
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 improves the reliability of the display device by ensuring proper electrical connections through the formation of well-defined contact holes that avoid the metallic polymer fence, enhancing the structural integrity and performance of the display substrate.
Implementation Method 1
The etching rate of the first insulating material in the second etching process is higher than an etching rate of the first insulation material in the first etching process
Implementation Method 2
the etching rate of the first insulating material in the second etching process is higher than an etching rate of the first insulation material in the first etching process
Data Source
AI summary
A display substrate includes a base substrate, a common line on the base substrate, a first insulation layer covering the common line and having a first insulating material, a conductive pattern on the first insulation layer and including a source electrode and a drain electrode, a second insulation layer covering the drain electrode and the common line, and including a lower second insulation layer having a second insulating material and an upper second insulation layer having the first insulating material, a first electrode electrically connected to the drain electrode through a first contact hole in the second insulation layer, and a second electrode electrically connected to the common line through a second contact hole in the first and second insulation layers. The upper and lower second insulation layers on the drain electrode have a first hole and a second hole respectively that form the first contact hole.