Sputter & Carbon Coaters

Magnetron Sputtering and Cool Plasma Technology

Quorum’s sputter coaters utilize magnetron sputtering technology, often referred to as "cool sputtering." By placing a high-strength magnet behind the target (cathode), the magnetic field traps electrons near the target surface, increasing ionization efficiency of the argon process gas. This allows the system to operate at lower voltages and currents, significantly reducing the thermal load on heat-sensitive biological specimens. The result is a fine-grained, continuous metal film that faithfully represents the sample's surface topography at high magnifications.

Pulsed and Ramped Carbon Rod Evaporation

For TEM support films and EDS applications, Quorum employs advanced carbon rod evaporation techniques. The systems utilize a ripple-free DC power supply to deliver precise pulses or ramps of current (typically up to 70 A) through the carbon source. Pulsed evaporation is technically superior as it minimizes the ejection of large carbon fragments (sparking), which can contaminate the sample. This controlled approach ensures the production of highly stable, uniform carbon films with thickness control down to a few nanometers, ideal for surface replicas and grid preparation.

High-Vacuum Turbomolecular Pumping Systems

Ultra-high-resolution imaging, particularly with Field Emission SEM (FE-SEM), requires extremely clean, high-vacuum environments. Quorum's "Turbo" range features internally mounted 70 L/s air-cooled turbomolecular pumps capable of reaching ultimate vacuums in the $1 \times 10^{-6}\text{ mbar}$ range. This high vacuum level is essential for sputtering oxidizing metals like Chromium and Iridium, which require an oxygen-free environment to prevent the formation of oxide layers that would result in a coarse grain structure and poor image quality.

Precision Film Thickness Monitoring (FTM)

To ensure quantitative accuracy in coating thickness, Quorum instruments integrate a Quartz Crystal Microbalance (QCM) as a film thickness monitor. This device measures the change in frequency of a vibrating quartz crystal as material is deposited. The system software converts this frequency shift into a real-time thickness reading in nanometers. This technical capability allows users to terminate the coating process automatically once a pre-defined thickness is reached, ensuring consistency across multiple batches and precise control for delicate thin-film applications.

Advanced Specimen Stages and Motion Control

The quality of a coating is highly dependent on the orientation of the specimen relative to the source. Quorum provides a variety of specimen stages, including standard 50 mm rotation stages, rotate-tilt stages, and planetary "Rotacota" stages. These stages utilize precise motor control to provide uniform coverage over complex 3D structures or heavily contoured samples. By rotating and tilting the specimen during deposition, the system ensures that "shadowing" effects are minimized, providing a continuous conductive path even in deep recesses of the sample.

Glow Discharge for Surface Modification

Many carbon-coated TEM grids are naturally hydrophobic, which prevents aqueous samples from spreading evenly. Quorum systems often include a glow discharge option, which uses a low-voltage plasma to modify the surface energy of the coating. This process can make a surface hydrophilic (negatively or positively charged) or be used for gentle plasma cleaning to remove adsorbed hydrocarbons. This technical step is vital for achieving high-quality results in cryo-EM and other applications involving aqueous biological suspensions.

Intelligent System Recognition and Automation

A hallmark of the Quorum platform is the "intelligent" recognition of coating inserts. The system automatically identifies whether a sputter head, carbon rod head, or metal evaporation boat is installed. Upon detection, the touchscreen interface updates to show only the relevant parameters and recipes for that specific process. This safety and efficiency feature prevents the accidental use of incorrect settings and allows multi-user laboratories to switch between different coating modalities rapidly and without manual reconfiguration of the software.

Modular Design for Large-Scale and Glovebox Applications

Recognizing the diverse needs of research, Quorum offers large-chamber versions of their coaters, capable of handling specimens up to 200 mm in diameter. Furthermore, specialized configurations like the glovebox-interfaced models allow for the preparation of air-sensitive materials, such as lithium-ion battery components. The modular design ensures that the vacuum chamber can be integrated directly into the glovebox floor, maintaining a controlled atmosphere while providing the same high-resolution sputtering and carbon coating capabilities as standalone units.

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