TFT Substrate Fabrication Using Three-Mask Process

Solution Overview

Problem

The complexity of manufacturing processes for liquid crystal display panels, particularly the thin film transistor substrate, results in increased manufacturing costs due to the need for multiple mask processes.

Innovation Solution

A method for fabricating a thin film transistor substrate using a three-mask process, which includes forming a gate line and gate electrode, a gate insulating film, and a semiconductor layer, followed by the formation of a pixel electrode and source/drain metal pattern, reducing the number of mask processes required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple mask processes are used for fabricating thin film transistor substrate, then manufacturing precision is improved, but device complexity increases and productivity decreases

Engineering Contradiction:

Improvefabrication precisionVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple mask processes into a single integrated mask process. The method forms the gate line, gate electrode, source/drain electrode, and pixel electrode simultaneously in one mask process, eliminating the need for separate mask processes for each component. This merging approach maintains manufacturing precision while significantly reducing process complexity and improving productivity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single mask process serves multiple functions by simultaneously defining multiple electrodes and conductive structures. The mask pattern is designed to create the gate line, gate electrode, source/drain electrode, and pixel electrode all in one step, making the mask process universal for forming all critical conductive elements of the thin film transistor substrate.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If multiple mask processes are used for fabricating thin film transistor substrate, then manufacturing precision is improved, but productivity decreases

Engineering Contradiction:

Improvefabrication precisionVSAvoidproduction efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent combines multiple mask processes into a single integrated mask process. The method forms the gate line, gate electrode, source/drain electrode, and pixel electrode simultaneously in one mask process, eliminating the need for separate mask processes for each component. This merging approach maintains manufacturing precision while significantly reducing process complexity and improving productivity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single mask process is designed to perform all necessary patterning operations in advance, before subsequent deposition and etching steps. By pre-defining all electrode patterns and structures in one mask process, the method eliminates the need for multiple sequential mask processes, thereby improving production efficiency without sacrificing precision.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If multiple mask processes are used for fabricating thin film transistor substrate, then manufacturing precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improvefabrication precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent combines multiple mask processes into a single integrated mask process. The method forms the gate line, gate electrode, source/drain electrode, and pixel electrode simultaneously in one mask process, eliminating the need for separate mask processes for each component. This merging approach maintains manufacturing precision while significantly reducing process complexity and improving productivity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7616284B2Liquid crystal display device and fabricating method thereof

Publication Date: 2009.11.10 LG DISPLAY CO LTD

AI summary

A liquid crystal display device, including: first and second substrates; a gate line on the first substrate; a data line crossing the gate line having a gate insulating film therebetween to define a pixel area; a pixel electrode formed of a transparent conductive film in a pixel hole passing through the gate insulating film in the pixel area; and a thin film transistor including a gate electrode, a source electrode, a drain electrode, and a semiconductor layer defining a channel between the source electrode and the drain electrode, wherein the semiconductor layer overlaps with a source and drain metal pattern including the data line, the source electrode and the drain electrode; and wherein the drain electrode protrudes from the semiconductor layer toward inside of the pixel electrode to be connected to the pixel electrode.