Thin Film Transistor Active Layer Etching via Source-Drain Mask

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Solution Overview

Problem

The region of the active layer between the source electrode and the drain electrode in thin film transistors is prone to pollution by organics during the manufacturing process, which degrades the performance of the transistors.

Innovation Solution

A method is developed where a photoresist layer is used to mask and etch the source-drain electrode layer first, followed by etching the active layer using the pattern of the source-drain electrode layer as a mask, employing dry etching with chemical gas plasma to prevent organic contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the photoresist layer is used to mask and etch the source-drain electrode layer first, then the active layer can be etched using the pattern of the source-drain electrode layer as a mask, but the active layer region is prone to pollution by organics during the manufacturing process

Engineering Contradiction:

Improveetching precisionVSAvoidorganic pollution

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the photoresist layer after it has served its masking function during the etching process. By taking out the photoresist after etching the source-drain electrode layer and before etching the active layer, the source of organic pollution is eliminated, preventing contamination of the active layer while maintaining the benefits of the photoresist masking process

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs the etching of the source-drain electrode layer while the photoresist mask is in place, before the photoresist is removed. This preliminary action ensures that the electrode layer is precisely patterned while the mask provides protection, and the mask is only removed after this critical step is completed, preventing organic contamination during subsequent active layer processing

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If the photoresist is not removed before etching the active layer, then organic substances may diffuse into the active layer, but removing the photoresist requires additional process steps

Engineering Contradiction:

Improveorganic contaminationVSAvoidprocess complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the photoresist removal step with the transition between etching the source-drain electrode layer and etching the active layer. The photoresist is removed immediately after serving its purpose as a mask for the source-drain electrode layer, combining the mask removal function with the process transition, thereby eliminating organic contamination without adding significant process complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent rushes through the photoresist removal step by performing it immediately after the source-drain electrode layer etching and before the active layer etching, minimizing the time the photoresist remains in the system and reducing the risk of organic diffusion into the active layer, while avoiding prolonged exposure to additional process steps

Inventive Principle:

Principle #21Skipping (Rushing through)

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 prevents pollution of the active layer region, thereby enhancing the performance of the thin film transistors by ensuring precise etching and avoiding organic diffusion.

Implementation Method 1

forming a photoresist layer on the source-drain electrode layer and forming a pattern of the photoresist layer via a pattern process; etching the source-drain electrode layer by using the pattern of the photoresist layer as a mask

Methodology Applied

Scientific EffectPhotomasking: Photography

Implementation Method 2

employing dry etching with chemical gas plasma to prevent organic contamination

Methodology Applied

Scientific EffectPlasma etching: Plasma

Implementation Method 3

employing dry etching with chemical gas plasma

Methodology Applied

Scientific EffectChemical reactions: Chemical Bonding

Data Source

PatentUS9508808B2Manufacturing method of thin film transistor and manufacturing method of array substrate

Publication Date: 2016.11.29 BOE TECHNOLOGY GROUP CO LTD

AI summary

A thin film transistor and manufacturing method thereof, an array substrate comprising the thin film transistor and manufacturing method thereof are provided. The method of manufacturing the thin film transistor comprises forming an active layer and a source-drain electrode layer, forming a photoresist layer on the source-drain electrode layer and forming a pattern of the photoresist layer by a pattern process; etching the source-drain electrode layer by using the pattern of the photoresist layer as a mask to form a pattern of the source-drain electrode layer including a source electrode and a drain electrode; and removing the photoresist, then etching the active layer by using the pattern of the source-drain electrode layer as a mask to form a pattern of the active layer.