LCD Contact Hole Formation via Protective Mask Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing process of liquid crystal display devices damages the surface of data and drain electrodes during etching, leading to reverse taper contact holes and increased contact resistance, which degrades the reliability and electrical characteristics of the devices.
Innovation Solution
A manufacturing method that forms a passivation layer over all layers, including gate, data, and drain electrodes, and creates wider second contact holes using a mask with specific light protection, transmission, and slit regions to prevent over-etching and protect the electrodes during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etching process is applied to remove the passivation layer and gate insulator, then the contact holes are formed to expose the data pad and drain electrode, but the surface of the data pad and drain electrode is damaged
Solution Approach 1:
A protective film is formed over the data pad and drain electrode before the etching process. This protective film is prepared in advance to prevent etching damage to the electrode surfaces during contact hole formation, while allowing the etching process to proceed normally for passivation layer removal.
Solution Approach 2:
The protective film acts as an intermediary layer between the etching process and the data pad/drain electrode. It mediates the interaction by being selectively removed or designed to protect specific areas, allowing contact holes to be formed without direct exposure of the electrode surfaces to the etching chemicals.
2Reliability
If the passivation layer is etched to form contact holes, then connectivity is established, but a reverse taper structure is formed preventing good connection
Solution Approach 1:
The etching parameters are modified by introducing a protective film that changes the etching dynamics. The protective film controls the etching rate and profile, preventing the formation of reverse taper structures and ensuring proper contact hole geometry for reliable electrical connection.
3Manufacturing precision
If the etching process is applied to expose the data pad, then the contact hole is formed, but the contact resistance increases due to surface damage
Solution Approach 1:
The protective film is prepared in advance over the data pad and drain electrode to prevent surface damage during the etching process. This preliminary protective action ensures that when contact holes are formed, the electrode surfaces remain intact and free from etching-induced damage, maintaining low contact resistance.
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 improves the electrical characteristics and reliability of LCD displays by preventing damage to the electrodes and maintaining a smooth surface profile, ensuring better connectivity and reduced contact resistance.
Implementation Method 1
using a mask including a light protection region, a light transmission region, and a slit region
Implementation Method 2
The light protection region of the mask defines a first region, the slit region defines a second region, the light transmission region defines a fourth region
Implementation Method 3
an etching process is applied to the photoresist layer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for forming a liquid crystal display device includes several regions. After forming a gate line layer (121), a gate insulator (140), a semiconductor layer (150,160), a data layer (170) and a photoresist layer (50), a mask (40) is used to define a plurality of regions in the photoresist layer. Certain of the regions have different thickness of the photoresist layer after developing. While exposing the gate pad (129) and data pad (179), etching process is applied over both the gate pad and data pad at the same time. Then, a passivation layer (180) is deposited over the gate pad and the data pad which are exposed via contact hole (181,182). While forming the other contact hole in the coating layer, both the data pad and the gate pad can be exposed to etching process within the same time period.