JJK 6MHz-14MM-Full-Covered Silver-Aluminum Alloy Crystal
Part No：SA6AF14
The SA6AF14 is a high-performance 6MHz AT-CUT quartz crystal, 14mm in diameter, designed for demanding thin-film deposition monitoring applications. This model features an advanced **full-covered Silver/Aluminum (Ag/Al) alloy electrode** process, combining the excellent conductivity of silver with the chemical stability of aluminum. Compared to traditional electrodes, the SA6AF14's silver-aluminum alloy layer exhibits superior oxidation resistance and wear resistance, effectively handling complex ionic environments in high vacuum. Its ≤15Ω ultra-low resonance resistance ensures high oscillation sensitivity even under complex loads. The full-covered electrode design achieves excellent surface stress distribution, and combined with the frequency-temperature characteristics of the AT cut, it greatly reduces the risk of 'frequency hopping' caused by thermal stress during high-power or prolonged PVD processes, making it a reliable choice for precision optical coating and semiconductor process monitoring.
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SA6AF14 Full-Covered Silver-Aluminum Alloy Crystal: The Preferred Choice for High-Precision 6MHz Vacuum Coating Monitoring
The SA6AF14 is an industrial-grade 6MHz monitor crystal, utilizing a 14mm standard AT-CUT quartz substrate, specifically developed for PVD deposition processes demanding high stability. The core feature of this model lies in its 'Full-Covered' silver-aluminum alloy electrode design. This structure not only provides a maximal electrical contact area but also ensures uniform heat distribution across the entire crystal surface. The 5.988MHz center frequency, combined with strict ±8KHz tolerance control, enables more accurate and repeatable rate monitoring feedback than standard crystals, particularly in precision optical coating and semiconductor thin-film production.
Full-Covered Silver-Aluminum Alloy Process: Balancing Conductivity and Aging Resistance
The SA6AF14 utilizes an innovative silver/aluminum alloy electrode solution, perfectly addressing the oxidation vulnerability of pure silver electrodes and the excessive stress of pure gold electrodes. The silver component ensures extremely low resonance resistance (≤15Ω), guaranteeing stable signals and easy oscillation even under high-load conditions for the sensor. The addition of aluminum forms a dense protective layer on the surface, significantly enhancing the electrode's oxidation resistance in high-vacuum environments. Furthermore, the 'Full-Covered Electrode' design effectively reduces stress concentration at the wafer's edges, better buffering the mechanical stress generated by deposited films, fundamentally curbing frequency hopping and signal loss commonly encountered during high-power evaporation processes.
Excellent Physical Characteristics & Multi-Scenario Applicability
Benefiting from its precise diameter of 13.97mm (±0.03mm) and AT-CUT process, the SA6AF14 exhibits excellent frequency-temperature stability, performing remarkably well within the 25°C to 75°C operating range. The 6MHz fundamental frequency configuration achieves an optimal balance between measurement sensitivity and film load capacity. Coupled with a 6-month shelf life and strict humidity control standards, it becomes an ideal choice for various high-value thin-film monitoring tasks. Whether dealing with complex multi-layer optical stacks or long-duration metallization sputtering processes, the SA6AF14 leverages its combined advantages of low impedance, corrosion resistance, and stress resilience to safeguard your production yield.
Product Specifications
| Part No | SA6AF14 |
| Nominal Frequency | 6.000MHz |
| Center Frequency | 5.988MHz |
| Frequency Tolerance | ±8KHz@25°C |
| Wafer Diameter | 13.97mm ± 0.03mm |
| Resonance Resistance | ≤15Ω |
| Crystal Cutting | AT-CUT |
| Electrode Material | Silver/Aluminum |
| Operating Temperature | 25°C ~ 75°C |
| Electrode Appearance | Full-Covered Electrode |
| Storage Temperature | -20°C ~ +85°C |
| Storage Humidity | Relative Humidity 30~50% |
| Storage Life | 6 months |
applications of the quartz monitor crystal
Find answers to the most frequently asked questions .
The full-covered electrode design eliminates the stress gradient at the edges typical of patterned electrodes, distributing the pressure from the deposited film more uniformly across the quartz surface. This significantly reduces the risk of 'frequency hopping' during high-power processes. Additionally, the full-surface metal coverage improves heat transfer efficiency, allowing the crystal to reach thermal equilibrium faster when exposed to thermal radiation from the evaporation source, drastically reducing initial frequency drift.
No, this is a testament to its high precision. In a real vacuum environment, once the crystal is installed and deposition begins, its frequency drops rapidly due to the added load. Precisely controlling the initial center frequency to 5.988MHz (±8KHz) ensures that after accounting for mounting load, the crystal still operates within the controller's optimal linear detection range, providing a longer effective monitoring life than standard crystals.
The silver-aluminum alloy represents an optimized solution for industrial environments: it retains silver's high conductivity for low resonance resistance (≤15Ω), while the alloying with aluminum creates a passivated protective layer, making its oxidation resistance far superior to pure silver. Moreover, it is more ductile than pure gold electrodes, effectively buffering the pull from high-stress films on the quartz substrate, preventing electrode layer delamination or peeling.
Resonance resistance is a key indicator of the crystal's quality factor (Q value). Low resistance means minimal energy loss during oscillation. In practical applications, even as the deposited film thickens and the load increases, the SA6AF14 maintains a strong, stable oscillation signal, avoiding 'thickness data jumps' or sensor errors caused by sudden impedance changes, ensuring consistency in complex processes.
The SA6AF14 adheres to extremely strict diameter tolerances, ensuring full compatibility with all major 14mm sensor heads (e.g., Inficon, Maxtek, Balzers, etc.). Due to its full-covered electrode design, specific angular alignment during installation is unnecessary, greatly simplifying the changeout process and reducing mechanical damping fluctuations caused by eccentric mounting.
The SA6AF14 utilizes an AT-CUT process, known for its superior frequency-temperature stability. Within this temperature range, frequency drift is minimized. Exceeding this range increases thermal stress on the quartz, potentially leading to decreased linearity. Therefore, using a water-cooled sensor head is recommended to maintain optimal measurement accuracy.
If your production line frequently encounters premature crystal failure, signal loss, or rapidly climbing R (resistance) values when depositing high-stress materials (like SiO2, Si3N4), the stress-buffering characteristics and low impedance advantages of the SA6AF14 will provide significant improvement. Furthermore, for operations demanding high repeatability across multiple runs, such as precision optical and semiconductor coating, this model is also a more stable choice.