Soft Mold Resist for LCD Pattern Transfer

Solution Overview

Problem

The existing photolithography process for fabricating liquid crystal display (LCD) devices is costly and has low production yield due to the need for high-priced photomasks and complex processes, and it struggles with forming high-quality patterns due to weak adhesion between the photoresist and the soft mold, especially when the mold has low surface energy.

Innovation Solution

A soft mold is created using a hydrophilic liquid prepolymer with a photoinitiator and surface active agent, which is cured with UV light and used to transfer patterns onto a substrate without the need for photolithography, improving adhesion and pattern formation by increasing the surface energy and hydrophilicity of the mold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photolithography process is used for fabricating LCD devices, then pattern formation can be achieved, but production cost increases and production yield decreases due to high-priced photomasks and complex processes

Engineering Contradiction:

Improvepattern formation qualityVSAvoidproduction yield

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention extracts and eliminates the photomask component from the traditional photolithography process. By using a soft mold with direct pattern contact, the expensive photomask is removed entirely, simplifying the process and reducing costs while maintaining pattern formation capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a soft mold that directly copies the master pattern onto the photoresist through physical contact. This copying mechanism replaces the optical copying method of photolithography, eliminating the need for photomasks and reducing process complexity

Inventive Principle:

Principle #26Copying

2Manufacturing precision

If photolithography process is used for fabricating LCD devices, then pattern formation can be achieved, but production cost increases due to high-priced photomasks and complex processes

Engineering Contradiction:

Improvepattern formation qualityVSAvoidproduction cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the photomask component from the traditional photolithography process. By using a soft mold with direct pattern contact, the expensive photomask is removed entirely, simplifying the process and reducing costs while maintaining pattern formation capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The soft mold serves as a disposable or reusable inexpensive pattern transfer tool that replaces expensive photomasks. The mold can be fabricated at low cost and used multiple times, significantly reducing per-unit production costs

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If soft mold with low surface energy is used for pattern transfer, then pattern formation is simplified, but adhesion between photoresist and mold deteriorates

Engineering Contradiction:

Improvepattern transfer process complexityVSAvoidadhesion between photoresist and mold

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The invention changes the surface energy parameter of the soft mold by selecting materials with inherently high surface energy or by applying surface treatments. This parameter change ensures strong adhesion between the mold and photoresist while maintaining the simplicity of the contact printing process

Inventive Principle:

Principle #35Parameter changes

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 method reduces production costs and increases yield by allowing for high-quality pattern formation on LCD devices, enhancing the adhesion between the soft mold and the photoresist, leading to improved pattern transfer and reduced defects.

Implementation Method 1

A resin layer containing a hydrophilic liquid prepolymer of 96 wt % or greater, a photoinitiator of about 1 wt % to 3 wt %, and a surface active agent of about 0.01 wt % to 1 wt % is coated on the master plate. The resin layer is cured by irradiating ultraviolet (UV) light to the resin layer.

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

A resin layer containing a hydrophilic liquid prepolymer of 96 wt % or greater, a photoinitiator of about 1 wt % to 3 wt %, and a surface active agent of about 0.01 wt % to 1 wt % is coated on the master plate.

Methodology Applied

Scientific EffectSurface energy modification: Surfactant

Data Source

PatentUS7838196B2Resist for soft mold and method for fabricating liquid crystal display using the same

Publication Date: 2010.11.23 LG DISPLAY CO LTD

AI summary

A soft mold resist for soft-lithography, a method for fabricating a soft mold, and a method for fabricating a liquid crystal display (LCD) device using the same where the soft mold includes a hydrophilic liquid prepolymer, a photoinitiator; and a surface active agent. A soft mold is formed by applying the soft mold resist to a back plate or a master plate and transferring a predefined pattern from the master plate to the soft mold resist. A display is formed by applying the soft mold to an etch resist layer overlying a thin film and transferring the predefined pattern to the etch resist, then etching the thin film using the etch resist as a mask. Additional processing step are carried out to form the LCD device.