OLED Mask Cleaning via Sacrificial Layer and Plasma

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Solution Overview

Problem

Current mask processing methods for OLED deposition face inefficiencies in removing impurities and reusing masks, particularly due to environmental concerns with wet cleaning methods and low cleaning efficiency when combining dry and wet cleaning processes.

Innovation Solution

A method involving the formation of a sacrificial silicon-containing layer on the mask, followed by transferring the mask to a second chamber for substrate processing, and then removing the sacrificial layer and organic impurities using a dry cleaning method, which includes plasmatized oxygen gas and specific gas reactions to decompose reaction by-products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If wet cleaning method is used to remove organic material from mask, then cleaning effectiveness is improved, but environmental pollution and wastewater generation increase

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidenvironmental pollution

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the wet cleaning method (chemical/liquid-based) with a dry cleaning method using plasma. The plasma generation unit creates plasma that chemically reacts with and removes organic materials from the mask surface without requiring liquid solvents, thereby eliminating wastewater generation while maintaining cleaning effectiveness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state of the cleaning medium from liquid (wet cleaning) to plasma state (dry cleaning). By controlling plasma parameters such as power, gas flow rate, and treatment time, the method achieves effective organic material removal without the environmental drawbacks of wet cleaning

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If dry cleaning and wet cleaning are combined to clean mask, then cleaning coverage is improved, but process complexity and time increase

Engineering Contradiction:

Improvecleaning coverageVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the wet cleaning step from the combined cleaning process. By using only dry plasma cleaning, the method simplifies the process while maintaining comprehensive cleaning coverage through optimized plasma treatment parameters and sufficient treatment time

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The plasma cleaning method serves multiple functions that were previously divided between dry and wet cleaning: it removes organic materials, eliminates residues, and prepares the surface for reuse, all through a single dry cleaning process

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If mask is reused after deposition, then productivity is improved, but impurity accumulation and cleaning difficulty increase

Engineering Contradiction:

Improvemask reuse efficiencyVSAvoidcleaning difficulty

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses plasma-based dry cleaning to replace wet cleaning methods, enabling effective removal of accumulated organic impurities from reused masks without the complications of solvent residues, thereby facilitating efficient mask reuse

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The plasma cleaning process automatically removes impurities from the mask surface through chemical reactions, leaving the mask clean and ready for reuse without requiring additional manual intervention or complex multi-step processes

Inventive Principle:

Principle #25Self-service

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 removes impurities and allows for the reuse of masks by enhancing cleaning efficiency and reducing environmental impact through dry cleaning, maintaining a vacuum state and minimizing wastewater generation.

Implementation Method 1

Step (a) may be performed by an atomic layer deposition (ALD) or chemical vapor deposition (CVD) method using a silicon containing precursor and a reaction gas

Methodology Applied

Scientific EffectChemical Vapor Deposition: Chemical Vapour Deposition

Implementation Method 2

The oxygen-containing gas may be plasmatized outside the first chamber and supplied into the first chamber

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 3

HF+NH3→NH4F

Methodology Applied

Scientific EffectChemical reaction: Reaction (physics)

Implementation Method 4

6NH4F+SiO2→(NH4)2SiF6+2H2O+4NH3

Methodology Applied

Scientific EffectChemical reaction: Reaction (physics)

Implementation Method 5

Step (c3) may be performed by a method of decomposing or evaporating reaction by-products through heating

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS20230314966A1Mask processing method and apparatus

Publication Date: 2023.10.05 TES CO LTD

AI summary

There are provided a mask processing method and a mask processing apparatus for reusing a mask used in an organic material deposition process. The mask processing method includes: (a) forming a sacrificial layer on a mask in a first chamber; (b) transferring the mask to a second chamber in which a substrate is disposed, and then processing the substrate using the mask; and (c) removing the sacrificial layer on the mask.