Thin-Film Transistor Substrate with Self-Protective Conductor Layer
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Solution Overview
Problem
Conventional thin-film transistor substrates face issues such as aluminum layer exposure during etching, hillock formation due to thermal expansion mismatches, and electrical instability from reaction with conducting layers, leading to poor performance and short-circuits.
Innovation Solution
A thin-film transistor substrate with a self-protective conductor layer structure, comprising a main conductor layer and a top conductor layer formed in a specific pattern to protect the main conductor layer from acid corrosion and ensure uniform coverage, using materials like aluminum, copper, molybdenum, and titanium, with etching steps to create a continuous structure that prevents hillock formation and electrical instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional metal lead structure with aluminum layer is used, then the conductor layer provides good electrical conductivity, but the aluminum layer is exposed and attacked by acid solution during etching process
Solution Approach 1:
The patent applies preliminary action by forming a protective molybdenum layer on the aluminum conductor layer before the etching process. This protective layer is prepared in advance to prevent the aluminum layer from being exposed and attacked by acid solution during subsequent etching steps, thereby resolving the contradiction between maintaining electrical conductivity and preventing acid corrosion.
Solution Approach 2:
The patent uses an intermediary approach by introducing a molybdenum protective layer as a mediator between the aluminum conductor layer and the acid etching solution. This intermediary layer protects the aluminum from direct contact with corrosive acid while allowing the etching process to proceed on other structures.
2Reliability
If the aluminum layer is used in the metal lead structure, then the conductor provides low resistance, but thermal expansion mismatch causes hillock formation and short-circuit
Solution Approach 1:
The patent applies composite materials by creating a multi-layer structure consisting of aluminum conductor layer combined with molybdenum protective layers. This composite structure leverages the low resistance of aluminum while the molybdenum layers provide thermal stability and prevent hillock formation caused by thermal expansion mismatch.
Solution Approach 2:
The patent uses parameter changes by modifying the thermal expansion characteristics of the conductor structure through the addition of molybdenum layers. The molybdenum layers have thermal expansion properties that complement aluminum, reducing the thermal stress and preventing hillock formation during temperature variations.
3Productivity
If the aluminum layer is exposed during etching, then the etching process can proceed, but aluminum atoms diffuse into the active layer causing poor device performance
Solution Approach 1:
The patent applies preliminary action by forming the molybdenum protective layer before the etching process to prevent aluminum atom diffusion into the active layer. This protective barrier is established in advance, allowing the etching process to proceed efficiently without causing contamination or performance degradation.
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 effectively prevents aluminum layer exposure, reduces hillock formation, and enhances electrical stability by creating a protective barrier, thereby improving the performance and reliability of thin-film transistor substrates.
Implementation Method 1
a top conductor layer having a first portion, second portion and third portion, wherein the first portion is formed on the main conductor layer
Data Source
AI summary
The invention provides a thin-film transistor substrate, including: a substrate; a metal lead structure formed on the substrate, wherein the metal lead structure includes: a main conductor layer formed on the substrate, wherein the main conductor has a sidewall; a top conductor layer having a first portion, second portion and third portion, wherein the first portion is formed on the main conductor layer, the second portion is formed on the sidewall of the main conductor layer, and the third portion is formed on the substrate, and a continuous structure is formed by the first portion, the second portion and the third portion.