Digital Holographic Microscopy for OLED Layer Alignment
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Solution Overview
Problem
Current OLED manufacturing processes face challenges in real-time monitoring and control of layer thickness and alignment, leading to poor alignment accuracy and significant yield loss due to end-of-line metrology delays and sensitivity to vibration, which affects device reliability and production efficiency.
Innovation Solution
An in-line process monitoring and control system using digital holographic microscopy (DHM) for real-time measurement of layer thickness and alignment, integrated within the OLED deposition system, allowing for immediate feedback and adjustment of deposition processes across multiple chambers, reducing the need for end-of-line measurements and minimizing vibration-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If end-of-line metrology systems are used to monitor completed substrates, then measurement capability is provided, but measurement time lag increases and alignment accuracy decreases
Solution Approach 1:
The patent applies preliminary action by performing thickness measurements during the deposition process itself, before the substrate exits the deposition chamber. The interferometer is positioned within the deposition chamber to measure layer thickness in real-time as material is being deposited, eliminating the need to wait until end-of-line for measurements.
Solution Approach 2:
The patent implements continuity of useful action by integrating the metrology system into the deposition process flow, allowing measurements to continue uninterrupted during deposition. The interferometer operates continuously throughout the deposition cycle, providing ongoing thickness data without requiring substrate removal or process interruption.
2Measurement precision
If optical imaging and ellipsometry techniques are used for end-of-line measurement, then layer thickness can be measured, but the system becomes sensitive to vibration and requires complex setup
Solution Approach 1:
The patent replaces mechanical measurement systems with an optical interferometry-based system. Instead of using mechanical contact methods or complex physical alignment systems, the invention uses light interference patterns to measure thickness, which are inherently less sensitive to mechanical vibrations and positioning errors.
Solution Approach 2:
The interferometer system serves multiple functions: it measures layer thickness, monitors deposition rate, and can detect alignment variations all through a single optical measurement system. This multi-functional approach reduces the need for separate specialized equipment for each measurement type.
3Productivity
If multiple deposition chambers are used to form multiple organic layers, then manufacturing capability is improved, but process complexity and alignment control difficulty increase
Solution Approach 1:
The patent implements feedback by using the real-time thickness measurements from the interferometer to monitor and control the deposition process across multiple chambers. Measurement data is fed back to the control system, which can adjust deposition parameters to maintain consistent alignment and thickness, making the complex multi-chamber process more controllable.
Solution Approach 2:
The patent applies segmentation by dedicating specific measurement regions within each deposition chamber to monitor specific layers. Each chamber has its own interferometer positioned to measure the thickness of the layer being deposited in that particular chamber, allowing independent monitoring and control of each deposition step.
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 enhances pixel placement accuracy, reduces production delays, and improves yield by enabling rapid, precise monitoring and control of OLED layer deposition, leading to improved device performance and reduced production costs.
Implementation Method 1
The metrology system includes a digital holographic microscope positioned to receive light from the workpiece and generate a thickness profile measurement of a layer on the workpiece
Implementation Method 2
a deposition chamber configured to deposit a first layer of organic material onto the workpiece
Data Source
AI summary
An organic light-emitting diode (OLED) deposition system has a workpiece transport system configured to position a workpiece within the OLED deposition system under vacuum conditions, a deposition chamber configured to deposit a first layer of organic material onto the workpiece, a metrology system having one or more sensors measure of the workpiece after deposition in the deposition chamber, and a control system to control a deposition of the layer of organic material onto the workpiece. The metrology system includes a digital holographic microscope positioned to receive light from the workpiece and generate a thickness profile measurement of a layer on the workpiece. The control system is configured to adjust processing of a subsequent workpiece at the deposition chamber or adjust processing of the workpiece at a subsequent deposition chamber based on the thickness profile.