Array Substrate Etching Process Reducing Photomask Count

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Solution Overview

Problem

The existing manufacturing processes for polymer stabilized vertically aligned (PSVA) display technologies require multiple photomasks and photolithography steps, leading to high costs and inefficiencies due to the complexity and instability of the Gray Tone Mask (GTM) process.

Innovation Solution

A method involving two etching processes on the passivation layer, where the first and second grooves have the same depth, and a third groove is etched to expose the metal layer, allowing for the reduction of one photomask and one photolithography step, thereby simplifying the process and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If three photomasks and three photolithography processes are used to form through holes and grooves with different depths, then the manufacturing precision of the PSVA structure is improved, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:

Improveetching depth precisionVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the formation of through holes and grooves with different depths into a single photolithography process using one photomask. The mask pattern is designed to simultaneously define both feature types, eliminating the need for separate photolithography steps and reducing overall process complexity while maintaining precise depth control through selective etching

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the etching process into two distinct stages: first forming through holes that penetrate the passivation layer, then forming grooves with controlled depths that do not penetrate completely. This segmentation allows different depths to be achieved through process sequencing rather than requiring multiple photomasks, thereby reducing device complexity while preserving manufacturing precision

Inventive Principle:

Principle #1Segmentation

2Productivity

If the GTM process is used to reduce the number of photomasks and photolithography processes, then the productivity is improved, but the process stability and reproducibility deteriorate due to the complicated parameter adjustments

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidprocess stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent maintains conventional photolithography parameters and procedures, avoiding the need to adjust complex GTM process parameters. By sticking to standard photomask-based photolithography with modified mask design, the process retains its inherent stability and reproducibility while achieving improved productivity through reduced process steps

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If three photomasks and photolithography processes are used, then the manufacturing precision of groove depths is improved, but the loss of time and manufacturing cost increase

Engineering Contradiction:

Improvegroove depth controlVSAvoidmanufacturing cycle time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent merges the definition of through holes and grooves into a single photolithography exposure step using one photomask. This consolidation reduces the number of sequential operations, thereby decreasing manufacturing cycle time while maintaining precise depth control through the combined mask pattern design and selective etching process

Inventive Principle:

Principle #5Merging (Combining)

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 results in a cost-effective and efficient manufacturing process by eliminating the need for additional photomasks and photolithography steps, improving the stability and reproducibility of the array substrate production.

Implementation Method 1

performing a first etching process on the passivation layer to obtain a first groove and a second groove; performing a second etching process on the passivation layer to obtain a third groove

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS9647015B2Method for manufacturing array substrate and array substrate manufactured therefor

Publication Date: 2017.05.09 TCL CHINA STAR OPTOELECTRONICS TECHNOLOGY CO LTD

AI summary

A method for manufacturing an array substrate is disclosed and includes steps of: sequentially forming a first metal layer, an insulating layer and a second metal layer on a glass substrate; forming a passivation layer on the second metal layer; performing a first etching process on the passivation layer to obtain a first groove and a second groove; performing a second etching process on the passivation layer to obtain a third groove; and forming a pixel electrode layer on the passivation layer. The method saves one photomask and a photolithography step, thereby reducing the cost and improving the efficiency.