Copper Drain Electrode Contact Hole Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In active matrix liquid crystal display devices, film-loss portions in the drain electrode during the washing process can lead to disconnected portions in the pixel electrode, causing connection defects and display anomalies due to the use of copper drain electrodes and the etching process.
Innovation Solution
The substrate design includes an insulating substrate with an auxiliary capacitance line, an insulating film, a copper drain electrode, and an interlayer insulating film, where the contact hole is formed to expose the side edge of the drain electrode, preventing film-loss in areas where the drain electrode is not present, ensuring reliable connection between the drain and pixel electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the drain electrode is made of copper and washed with oxidant aqueous solution, then cleaning is achieved, but film-loss portion is formed in the drain electrode
Solution Approach 1:
The contact hole formation process is segmented into two distinct regions: a first contact hole region where the drain electrode is exposed and a second contact hole region where the drain electrode is not exposed. This segmentation allows selective washing - the oxidant aqueous solution is applied only in the second region where the drain electrode is absent, preventing film-loss while maintaining cleaning effectiveness where needed.
Solution Approach 2:
Different regions of the contact hole are given different properties: the first contact hole region (overlapping drain electrode) is protected from oxidant exposure to prevent film-loss, while the second contact hole region (without drain electrode) receives the oxidant washing for proper cleaning. This local differentiation of washing application resolves the contradiction between cleaning needs and electrode integrity.
2Reliability
If the contact hole is formed to expose the drain electrode, then electrical connection is enabled, but film-loss portion and disconnected portion are formed
Solution Approach 1:
The contact hole is divided into two functional regions: a first region that exposes the drain electrode for electrical connection, and a second region that does not expose the drain electrode to prevent film-loss. This segmentation allows the contact hole to simultaneously achieve both electrical connectivity and prevent manufacturing defects.
Solution Approach 2:
Different portions of the contact hole structure are given different characteristics: the first contact hole region provides electrode exposure for connection, while the second contact hole region prevents film-loss by excluding oxidant from areas without drain electrode protection. This local quality differentiation resolves the contradiction between connection reliability and electrode integrity.
3Ease of manufacture
If washing is performed with oxidant aqueous solution, then contamination is removed, but film-loss portion is formed in copper drain electrode
Solution Approach 1:
The washing process is spatially segmented into a first contact hole region where the drain electrode is exposed (no washing to prevent film-loss) and a second contact hole region where the drain electrode is not exposed (washing applied for contamination removal). This segmentation enables selective contamination removal without causing film-loss in protected regions.
Solution Approach 2:
The oxidant aqueous solution is applied locally only in the second contact hole region where the drain electrode is absent, providing contamination removal exactly where needed without exposing the copper drain electrode to oxidants that would cause film-loss in the first contact hole region.
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 configuration prevents disconnection of the pixel electrode around the entire contact hole and maintains the connection between the drain and pixel electrodes, thereby preventing display anomalies caused by connection defects.
Implementation Method 1
a pixel electrode formed on the interlayer insulating film and electrically connected to the drain electrode through a contact hole
Implementation Method 2
the washing fluid sometimes causes a film-loss portion 64a to be formed in the drain electrode 64
Data Source
AI summary
This thin film transistor substrate is provided with: a drain electrode that is formed on an insulating film, and comprises copper; an interlayer insulating film formed on the drain electrode; and a pixel electrode that is formed in the contact hole, which is formed in the insulating film and the interlayer insulating film, and on the interlayer insulating film, and is electrically connected to the drain electrode via the contact hole. In a plan view of the contact hole, the drain electrode is formed inside part of the contact hole in such a manner that part of the drain electrode and part of the outer periphery of the contact hole are overlapping, and part of the pixel electrode and the drain electrode are electrically connected.