Thin-Film Transistor Etch Stopper Layout for Precise Contact Vias

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Solution Overview

Problem

The conventional manufacturing method of thin-film transistors faces challenges with over-etching and under-etching during the formation of contact vias, leading to reduced yield and quality issues.

Innovation Solution

The method involves forming etch stoppers between the active layer and the insulating layer, which blocks etching and allows for precise formation of contact vias, preventing over-etching and ensuring complete exposure of the etch stoppers, thereby improving the yield of thin-film transistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional etching process is used to form contact vias, then manufacturing process is simple, but etching precision deteriorates leading to over-etching and under-etching

Engineering Contradiction:
Improveetching precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

An etch stopper layer is formed before the insulating layer to prevent over-etching during contact via formation. This preliminary protective action ensures that the etching process stops at the desired depth, eliminating the need for complex etching control mechanisms and improving etching precision without significantly increasing overall process complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The etch stopper layer acts as an intermediary between the insulating layer and the active layer. It mediates the etching process by providing a controlled stopping point, preventing direct contact between the etchant and the active layer, thus avoiding both over-etching and under-etching issues.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If etching process is controlled more strictly, then etching precision improves, but manufacturing complexity increases

Engineering Contradiction:
Improvecontact via precisionVSAvoidmanufacturing ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The etch stopper layer provides self-regulating etching control. The etching process automatically stops when it reaches the etch stopper layer, eliminating the need for complex real-time monitoring and control systems. This self-service mechanism maintains high etching precision while simplifying the manufacturing process.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

By pre-forming the etch stopper layer with appropriate material properties and thickness, the system establishes built-in etching depth control. This preliminary preparation eliminates the need for complex process control during etching, making manufacturing easier while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

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 addresses the issues of under-etching and over-etching, enhancing the production yield and maintaining electrical conductivity between the active layer and electrodes.

Implementation Method 1

The composition is capable of blocking etching to the first layer during formation of the at least one contact via in the second layer

Methodology Applied
Scientific EffectEtch stopper:

Data Source

PatentEP3437140B1Thin-film transistor and manufacturing method thereof, array substrate, and display apparatus
Publication Date: 2025.01.01 BOE TECHNOLOGY GROUP CO LTD
  • EP3437140B1 patent drawingFigure 1~2
  • EP3437140B1 patent drawingFigure 3~4
  • EP3437140B1 patent drawingFigure 5~6

AI summary

The present disclosure provides a method for manufacturing a thin-film transistor and a thin-film transistor manufactured thereby, an array substrate and a display apparatus. The method comprises: forming a first layer; forming at least one etch stopper over the first layer; forming a second layer over the first layer and the at least one etch stopper; forming at least one contact via in the second layer, such that a bottom opening of each contact via contacts with a top surface of one etch stopper; and forming at least one electrode in the at least one contact via, such that each electrode extends in one contact via respectively, and is in contact with, and electrically coupled with, the one etch stopper. The at least one etch stopper comprises a composition. The composition is capable of blocking etching to the first layer during formation of the at least one contact via in the second layer; and the composition also has one of the following characteristics: an oxidization product of the composition is readily removable by a solution; an oxidization product is conductive; or the composition is resistant to oxidization.