Display Device Contact Hole Sidewall Taper Control
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Solution Overview
Problem
The existing display device fabrication processes often result in damage to semiconductor layers and can lead to seam formation in subsequent layers, affecting the reliability and quality of the display device due to the acute angle of sidewalls in insulating layers.
Innovation Solution
A display device is fabricated using a method where a first conductive layer and a second conductive layer are formed with a positive taper shape sidewall of the insulating layer defining a contact hole, preventing exposure of the active pattern and minimizing damage, and using a halftone mask for precise etching to maintain the integrity of the semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional etching process is used to form contact holes, then the fabrication process is simple, but the sidewall of the insulating layer forms an acute angle causing exposure of the active pattern and damage to the semiconductor layer
Solution Approach 1:
The patent applies preliminary action by forming a protective layer on the active pattern before etching the insulating layer. This protective layer prevents the active pattern from being exposed during etching, allowing the formation of contact holes with positive taper sidewalls without damaging the semiconductor layer. The protective layer is removed after etching, completing the process.
Solution Approach 2:
The patent introduces a protective layer as an intermediary element between the etching process and the active pattern. This intermediary layer absorbs the harmful effect of the etchant, preventing direct contact with the active pattern and enabling precise sidewall angle control during etching.
2Reliability
If the sidewall of the insulating layer has an acute angle, then the contact hole can be formed, but the active pattern is exposed and damage to the semiconductor layer occurs
Solution Approach 1:
The protective layer is formed in advance on the active pattern before etching. This preliminary action ensures that during the etching process, the active pattern remains protected even as the insulating layer is removed to form contact holes with positive taper sidewalls, maintaining both reliability and precision.
Solution Approach 2:
The protective layer serves as a cushioning layer that absorbs the mechanical and chemical stress during etching. By providing this beforehand cushioning, the active pattern is protected from damage while allowing precise control of the contact hole shape and sidewall angle.
3Productivity
If the contact hole etching is performed without protecting the active pattern, then the process is straightforward, but seam formation occurs in subsequent layers affecting device quality
Solution Approach 1:
The protective layer is formed beforehand on the active pattern, enabling the etching process to proceed efficiently without compromising layer alignment quality. This preliminary protection prevents seam formation in subsequent layers while maintaining high fabrication efficiency.
Solution Approach 2:
The protective layer acts as an intermediary that enables the etching process to be performed without direct exposure of the active pattern. This intermediary protection prevents seam formation in subsequent layers, ensuring high layer alignment quality while maintaining process efficiency.
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 fabrication process and enhances the quality of the display device by preventing seam formation and reducing damage to the semiconductor layer, ensuring accurate contact hole formation and improved layer alignment.
Implementation Method 1
a method of fabricating the display device... includes forming a contact hole penetrating the first insulating layer and the second insulating layer... using a halftone mask for precise etching
Data Source
AI summary
A display device includes: a substrate; a first conductive layer on the substrate and including a first pattern; a first insulating layer on the first conductive layer; a semiconductor layer on the first insulating layer and including an active pattern; a second insulating layer on the semiconductor layer; and a second conductive layer on the second insulating layer, wherein the second conductive layer includes a first electrode partially in contact with the active pattern, the first electrode is in contact with the first pattern through a first contact hole, the first contact hole penetrates the first insulating layer and includes a first hole defined by a sidewall of the first insulating layer, and a second hole defined by a sidewall of the active pattern and a sidewall of the second insulating layer, and a width of the second hole is greater than a width of the first hole.