QCM Sensor Buffer Electrode Design for Deposition Uniformity
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Solution Overview
Problem
Existing deposition methods for display apparatuses, such as OLEDs and LCDs, face challenges in achieving a uniform thickness of deposition films, as they lack effective real-time monitoring and control of deposition material amounts.
Innovation Solution
A quartz crystal microbalance (QCM) sensor is developed, comprising a crystal plate with buffer and electrode layers, where the electrode includes metals with a hexagonal close-packed lattice structure, and a buffer layer with higher electrical activity, allowing for real-time measurement of deposition material thickness and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used without real-time monitoring, then the deposition process is simpler and faster, but the uniformity of deposition film thickness deteriorates
Solution Approach 1:
The QCM sensor provides real-time feedback on deposition thickness by measuring frequency changes in the crystal plate. The sensor is positioned to receive deposition material simultaneously with the substrate, allowing continuous monitoring and control of film thickness uniformity during the deposition process
Solution Approach 2:
The patent replaces complex optical or profilometric measurement systems with a mechanical vibration-based QCM sensor. The crystal plate's resonance frequency changes in response to deposited mass, providing a simple yet precise mechanical method for real-time thickness monitoring
2Strength
If the electrode layer is made thicker to improve adhesion, then adhesion performance improves, but the total resistance of the sensor increases
Solution Approach 1:
The patent optimizes the thickness parameter of the electrode layer to achieve the minimum required thickness for adequate adhesion while maintaining low electrical resistance. The buffer layer composition and thickness are also adjusted to provide adhesion enhancement without adding significant resistance
Solution Approach 2:
The patent uses a composite structure consisting of a buffer layer and an electrode layer. The buffer layer (e.g., chromium, molybdenum) provides strong adhesion to the crystal plate, while the electrode layer (e.g., aluminum, gold) provides low electrical resistance, creating a synergistic multi-layer system
3Strength
If multiple buffer layers are added to improve adhesion and protection, then adhesion and durability improve, but the device structure becomes more complex
Solution Approach 1:
The patent applies buffer layers selectively at specific locations where adhesion and protection are most critical, such as at the interfaces between the crystal plate and electrode, or at edges prone to mechanical stress, rather than uniformly across the entire surface
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
The QCM sensor enables real-time monitoring and control of deposition material thickness, ensuring a uniform deposition film, improving adhesion and sensing performance by adjusting the thickness ratio of the buffer and electrode layers, and reducing total resistance.
Implementation Method 1
a crystal plate, a buffer layer, and an electrode. The crystal plate has a first surface and a second surface
Implementation Method 2
An electrical activity of the buffer layer may be higher than an electrical activity of the electrode. A total resistance of the QCM sensor may be about 15Ω or less.
Data Source
AI summary
A quartz crystal microbalance (QCM) sensor includes a crystal plate, a buffer layer, and an electrode. The crystal plate has a first surface and a second surface. The second surface is opposite the first surface. The buffer layer includes a first buffer layer and a second buffer layer. The first buffer layer is disposed on the first surface of the crystal plate, the second buffer layer is disposed on the second surface of the crystal plate. The electrode includes a first electrode and a second electrode. The first electrode is disposed on the first buffer layer. The second electrode is disposed on the second buffer layer. The electrode includes at least one of titanium, scandium, beryllium, cobalt, yttrium, zirconium, technetium, ruthenium, lanthanum, cerium, praseodymium, neodymium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, lutetium, hafnium, rhenium, osmium, americium, curium, berkelium, and californium.