Metal Oxide Transistor Gate Structure and Plasma Treatment
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Solution Overview
Problem
Display devices with metal oxide semiconductors face corrosion issues due to process gases remaining on patterned lines during the etching process, leading to reliability and quality concerns.
Innovation Solution
A display device design featuring a metal oxide semiconductor transistor with a specific gate structure and plasma surface treatment to prevent corrosion, including a first gate with conductive layers and a gate insulation pattern, where the uppermost layer is divided into parts with stepped surfaces, and a method of manufacturing that involves sequential etching processes and plasma treatment to minimize photoresist loss and prevent chloride ion corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an etching process is used to form transistor lines, then the transistor structure can be created, but process gases remain on the patterned lines causing corrosion
Solution Approach 1:
A plasma treatment process is performed immediately after the etching process to remove process gases from the patterned lines before they can cause corrosion. This preliminary action prevents the harmful effect of gas accumulation while maintaining the benefits of the etching process for line formation.
Solution Approach 2:
The plasma treatment process, which could be seen as an additional step, actually converts the harmful residual gases into removable byproducts. The plasma energy activates and breaks down the adsorbed process gases, transforming them into volatile species that can be easily evacuated, thus turning a potential corrosion source into a removable contaminant.
2Reliability
If a multi-layer gate structure is used, then electrical performance is improved, but manufacturing complexity increases
Solution Approach 1:
Different conductive layers in the gate structure are assigned different materials with specific electrical properties optimized for their local function. The first conductive layer uses a material with lower resistivity for current conduction, while the second layer uses a material with higher resistivity for field control, creating local quality variations that improve overall electrical performance.
Solution Approach 2:
The gate structure employs a composite of multiple conductive materials stacked together, each contributing different electrical characteristics. This composite structure allows the gate to simultaneously achieve low resistance for power efficiency and high resistance for field control, properties that cannot be obtained with a single material.
3Manufacturing precision
If photoresist is used during etching, then patterning precision is achieved, but photoresist loss occurs leading to bright spot defects
Solution Approach 1:
The plasma treatment process acts as an intermediary step between etching and subsequent processing. It selectively removes photoresist debris and process gases from the patterned lines without affecting the underlying transistor structure, thereby eliminating the source of bright spot defects while preserving patterning precision.
Solution Approach 2:
Instead of using mechanical or chemical cleaning methods that might damage the photoresist or underlying structures, the invention uses plasma treatment—a field-based method—to remove contaminants. The plasma energy selectively removes organic photoresist residues and inorganic process gases without physical contact, preventing bright spot defects while maintaining patterning accuracy.
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
The solution enhances the reliability and display quality by preventing leakage current and reducing bright spot defects, ensuring improved performance and longevity of the display device.
Implementation Method 1
performing a plasma surface treatment on the first gate, the gate insulation pattern, and the photoresist pattern
Data Source
AI summary
A display device is disclosed that includes a base layer, a light-emitting element, and a pixel circuit. The pixel circuit includes a first transistor, and the first transistor includes a metal oxide semiconductor pattern, a first gate having a plurality of conductive layers, and a gate insulation pattern. The uppermost layer among the plurality of conductive layers is divided into a first part adjacent to a drain region, a second part adjacent to a source region, and a third part between the first part and the second part. An upper surface of each of the first part and the second part may form a step with an upper surface of the third part. A sum of the widths of the upper surfaces of the first part and the second part may be smaller than the width of the upper surface of the third part.