OLED Deposition Chuck Flatness Control for Uniform Vapor Jet Printing

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Solution Overview

Problem

Existing OLED fabrication technologies face challenges in achieving high precision and uniformity in depositing organic layers on large-area substrates, particularly due to limitations in chuck surface flatness, which affects the performance and reliability of the devices.

Innovation Solution

A substrate holding device with a clamp surface and substrate holder featuring a flatness tolerance of not greater than specified micrometers, utilizing a closed-loop polishing process for optical interferometric measurement to achieve precise surface flatness, and incorporating a pressure-vacuum chuck for secure holding during material deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional substrate holding systems are used, then device complexity is reduced, but manufacturing precision deteriorates due to inability to achieve sub-micron flatness tolerance

Engineering Contradiction:

Improvesubstrate flatness toleranceVSAvoidsubstrate holding system structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The substrate holding system is divided into multiple independent layers: a base layer and a chuck layer with separate flatness control mechanisms. This segmentation allows each layer to be optimized independently for its specific function, enabling sub-micron flatness achievement without overwhelming system complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary flatness adjustment through closed-loop polishing and optical interferometric measurement before the actual deposition process. This preliminary action ensures the substrate surface meets sub-micron flatness requirements in advance, preventing deposition non-uniformity.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If sub-micron flatness tolerance is achieved through closed-loop polishing and optical interferometric measurement, then manufacturing precision is improved, but device complexity and measurement requirements increase

Engineering Contradiction:

Improvesurface flatnessVSAvoidsurface flatness measurement

Core Design Contradiction:

Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system implements closed-loop feedback control where optical interferometric measurement continuously monitors surface flatness during the polishing process. The measurement data feeds back to adjust polishing parameters in real-time, ensuring sub-micron flatness is achieved and maintained without requiring excessively complex measurement systems.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system replaces complex mechanical measurement methods with optical interferometric measurement. This substitution provides higher precision surface flatness detection capability while avoiding the mechanical complexity and contact issues associated with traditional mechanical measurement systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If multi-layered chuck structure with sub-micron flatness is used, then deposition uniformity is improved, but ease of manufacture deteriorates

Engineering Contradiction:

Improvedeposition uniformityVSAvoidsubstrate holding system fabrication

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The multi-layered chuck structure is segmented into standardized base and chuck layers that can be manufactured separately using conventional machining techniques. Each layer is designed with standard tolerances that are easier to achieve, and the layers are assembled to achieve the final sub-micron flatness, simplifying the overall manufacturing process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each layer is pre-polished and pre-measured for flatness before assembly. This preliminary preparation allows the final assembly to achieve sub-micron flatness through simpler alignment and bonding operations, rather than requiring the entire multi-layer structure to be machined to sub-micron tolerances as a single piece.

Inventive Principle:

Principle #10Preliminary action

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

Enhances the flatness and stability of substrate holding, allowing for more precise and uniform deposition of organic layers, thereby improving the performance and reliability of OLEDs, especially on larger substrates.

Implementation Method 1

optical interferometric measurement for surface flatness adjustment

Methodology Applied

Scientific EffectOptical interferometry: Interference

Implementation Method 2

vacuum or electrostatic chucking mechanisms to secure the substrate

Methodology Applied

Scientific EffectVacuum pressure: Vacuum

Implementation Method 3

vacuum or electrostatic chucking mechanisms to secure the substrate

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Data Source

PatentUS12628545B2Organic vapor jet printing system

Publication Date: 2026.05.12 UNIVERSAL DISPLAY CORP

AI summary

A chuck for holding a workpiece in a deposition system is provided, which includes a base having a base surface with a flatness tolerance of not greater than 30 μm and a clamp having a surface configured to be attached to a substrate, which has a flatness tolerance of not greater than 30 μm. The clamp also includes a substrate holder configured to hold a substrate above the second clamp surface.