OLED Deposition In-Line Metrology for Thickness and Dopant Control
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Solution Overview
Problem
Existing OLED production lines face challenges in real-time monitoring of dopant concentrations and layer thicknesses, leading to device performance issues and increased production costs due to delays in detecting deposition process abnormalities.
Innovation Solution
An in-line process monitoring and control system that uses reflectometry and photoluminescence measurements within a transfer chamber between deposition chambers to provide immediate feedback on film thickness and doping concentrations, allowing for rapid adjustments and integration with existing hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If end-of-line metrology systems are used to monitor OLED substrates after complete deposition, then device specifications can be verified, but real-time process control is lost and production delays occur
Solution Approach 1:
The patent implements in-line metrology measurements within the deposition chamber before the deposition process completes, allowing real-time detection of layer thickness and dopant concentration. This preliminary measurement approach enables immediate process adjustments without waiting for end-of-line inspection, thereby eliminating production delays while maintaining measurement precision.
Solution Approach 2:
The system incorporates real-time feedback mechanisms where metrology measurements are continuously taken during deposition, and process parameters are dynamically adjusted based on measured values. This closed-loop feedback control ensures both precise measurement and real-time process correction, resolving the contradiction between measurement accuracy and production speed.
2Loss of time
If traditional ellipsometry methods are used for in-line monitoring, then real-time feedback is achieved, but the system becomes highly sensitive to vibrations and complex to integrate
Solution Approach 1:
The patent changes the measurement parameters from traditional ellipsometry to alternative optical techniques that are less sensitive to vibration. By modifying the measurement approach while maintaining real-time capability, the system achieves robust in-line monitoring without the vibration sensitivity problems of ellipsometry.
Solution Approach 2:
The system employs simpler, more robust metrology components that are easier to integrate and less sensitive to environmental disturbances. These alternative measurement tools provide sufficient precision for process control while being more resilient to vibrations and easier to implement in the deposition chamber environment.
3Reliability
If multiple deposition chambers are used to form OLED layers sequentially, then device performance is improved, but process monitoring complexity increases
Solution Approach 1:
The patent implements a universal metrology system that can measure multiple parameters (layer thickness, dopant concentration, optical properties) across all deposition chambers using the same measurement principles. This multi-functional approach simplifies the overall monitoring system complexity while maintaining comprehensive process control for improved device performance.
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 system enables real-time monitoring and control of OLED deposition, improving device performance, yield, and reducing production costs by detecting issues before significant portions of wafers are processed, and is less sensitive to vibrations and easier to integrate than traditional methods like ellipsometry.
Implementation Method 1
At least one of the one or more sensors is positioned to receive reflections of the first light beam from the workpiece within the transfer chamber to perform reflectometry measurements and generate a thickness measurement of a layer on the workpiece from the reflectometry measurement
Implementation Method 2
a second light source to generate a second light beam to induce photoluminescence in the layer on the workpiece in the transfer chamber. At least one of the one or more sensors is positioned to receive emissions from the layer on the workpiece within the transfer chamber to perform photoluminescence measurements of the layer on the workpiece
Data Source
AI summary
An organic light-emitting diode (OLED) deposition system includes two deposition chambers, a transfer chamber between the two deposition chambers, a metrology system having one or more sensors to perform measurements of the workpiece within the transfer chamber, and a control system to cause the system to form an organic light-emitting diode layer stack on the workpiece. Vacuum is maintained around the workpiece while the workpiece is transferred between the two deposition chambers and while retaining the workpiece within the transfer chamber. The control system is configured to cause the two deposition chambers to deposit two layers of organic material onto the workpiece, and to receive a first plurality of measurements of the workpiece in the transfer chamber from the metrology system.