Etching Stopper Electrode for LCD Contact Resistance
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Solution Overview
Problem
In liquid crystal display devices using an electric field substantially horizontal with respect to a transparent substrate, the manufacturing process can result in increased contact resistance and poor connections due to residual deposits from dry etching, leading to issues like poor display and signal delay, and removing these deposits can cause over-etching and reduce yields.
Innovation Solution
The method involves forming a switching element with a drain electrode on a substrate, covering it with a first insulating film, creating openings to expose the drain electrode, and using a first etching stopper electrode connected to the drain electrode. A second insulating film is formed, and selective etching is performed to remove residues on the etching stopper electrode, allowing for the connection of pixel and common electrodes without damaging other layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If residual deposit is removed by etching, then contact resistance is reduced, but other layers are also etched causing poor formation and reduced yields
Solution Approach 1:
The patent segments the etching process into two distinct stages: a first etching process that removes residual deposits from the drain electrode region, and a second etching process that removes deposits from the common electrode region. This segmentation allows each etching step to be optimized independently, preventing over-etching of sensitive layers while ensuring thorough removal of residual deposits that cause contact resistance.
Solution Approach 2:
The patent applies preliminary protective measures by forming a protective film over the common electrode before the first etching process. This preliminary action prevents the common electrode and its associated layers from being damaged during subsequent etching operations, allowing the drain electrode region to be cleaned without compromising the integrity of other layers.
2Reliability
If residual deposit is removed by etching, then connection quality is improved, but yields are reduced due to over-etching
Solution Approach 1:
The patent divides the manufacturing process into sequential etching stages with distinct objectives. The first etching process targets residual deposits affecting drain electrode connections, while the second process addresses deposits affecting common electrode connections. This segmentation ensures that each connection quality issue is addressed without sacrificing overall manufacturing yields through unnecessary over-etching.
Solution Approach 2:
The patent introduces a protective film as an intermediary layer during the etching process. This intermediary protects sensitive regions (common electrode and its insulating film) from the harsh etching environment while allowing the drain electrode region to be properly cleaned. This mediator enables improved connection quality without the penalty of reduced yields from over-etching damage.
3Ease of manufacture
If conventional manufacturing process is used, then production is simplified, but contact resistance increases due to residual deposit
Solution Approach 1:
The patent incorporates preliminary protective film formation as an early step in the manufacturing process, before the etching operations begin. This preliminary action adds minimal complexity to the overall process while effectively preventing the contact resistance problem caused by residual deposits. The protective film is formed using standard thin-film deposition techniques that are already part of conventional manufacturing workflows.
Solution Approach 2:
The patent segments the etching process into two controlled stages, each with specific purposes. While this adds a step to the manufacturing process, each segment uses standard etching equipment and procedures. The first segment removes deposits from the drain electrode area, and the second segment addresses the common electrode area, maintaining reliability without requiring entirely new manufacturing capabilities.
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 reduces contact resistance and prevents peeling or poor connections between electrodes, maintaining display quality and reducing yield loss by precisely managing the etching process with etching stoppers, ensuring reliable signal transmission and improved manufacturing efficiency.
Implementation Method 1
selectively etching the second insulating film on the first etching stopper electrode in a first etching process
Implementation Method 2
removing a residue on the first etching stopper electrode by etching in a second etching process
Data Source
AI summary
A liquid crystal display device comprising: a switching element that has a drain electrode and that is arranged on a substrate; a first insulating film that covers the switching element and that has a first opening on the drain electrode; a first etching stopper electrode that is formed in the first opening and that is connected to the drain electrode; a common electrode that is arranged on the first insulating film; a second insulating film that covers the first etching stopper electrode and the common electrode, and that has a second opening on the first etching stopper electrode; and a pixel electrode that is connected through the second opening to the first etching stopper electrode and that extends onto the second insulating film so as to face the common electrode.