Application Note

Stable & fast gas flow control for vacuum deposition

Vacuum deposition by reactive sputtering

In vacuum deposition equipment mass flow controllers are used for the supply of gases. Bronkhorst newest flexible gas flow controller (FLEXI-FLOW) is an excellent choice for vacuum deposition processes by reactive sputtering, due to its fast response. It reaches setpoints within 100 milliseconds. The flow controller has a large dynamic flow range suitable to control gas flows from 0,5 mln/min up to 20 ln/min, which largely accommodates for the requirements of reactive sputtering.

Reactive sputtering is a layer deposition technique where sputtered particles react with a gas that is introduced to the sputtering chamber. To this end, high-energy argon bombards a target, usually a plate of metal such as aluminium, releasing a vapour of sputtered metal particles. They react with the supplied reactive gases, typically oxygen or nitrogen, allowing very thin ceramic layers to be deposited on glass, silicon wafers, metal or polymer. Reactive sputtering is used for applying coatings for anti-reflection, hardening, anti-wear, anti-corrosion, etc. Mass flow controllers play a highly relevant role in the supply of gases.

Check out the Bronkhorst solution
Flow control in Reactive sputtering for laptop screens
Vacuum deposition by reactive sputtering can be applied for computer screens

Requirements for reactive sputtering

In vacuum deposition technology, fast flow control is essential. Each second saves time, saves energy, resulting in a better efficiency of the deposition equipment. The gas flows need to be supplied with a large dynamic flow range, in a reproducible way and with long-term stability.

Check our recommended products

Important topics

  • Fast response flow control
  • Reproducibility and long-term stability
  • Service-friendly
  • Robust device for demanding applications

Process solution

The FLEXI-FLOW mass flow controller reaches 100 msec response time without overshoot. This way, we can meet the requirements of vacuum coating customers that need multi-channel flow solutions offering stable and fast flow control in combination with shut-off functionality.

Fast response flow control

End-users of vacuum deposition equipment require a very fast responding gas supply system. They optimise process conditions like pressure and gas flow and monitor the result by measuring the coating thickness during the coating process. During the process, there should be a stable, controlled gas flow to keep the coating of the correct thickness and composition.

Fast flow control with FLEXI-FLOW

When the sputter system observes that the thickness or transparency is deviating, it corrects the deposition process by adjusting the gas flows. Therefore, a very fast flow control is desired with a response in the 100-millisecond range.

The FLEXI-FLOW mass flow controller can do this. In case there are variations in inlet pressure, the gas flow controller keeps the flow at the setpoint as responsive as possible. When there are changes in the reactor chamber, the flow controller receives a new setpoint. This way, fast response to new setpoints results in less waste and less rejected products.

Shut-off functionality

A shut-off valve can be integrated to minimise leakage to the vacuum chamber in the phase of vacuuming - especially useful in ultra-high vacuum reactors.

Large dynamic range

The large dynamic flow range with a high turndown ratio of at least 1:1000 reduces the number of models and spare parts needed and improves the flexibility of the vacuum deposition equipment.

Wide interface capability

Compact multi-channel solutions are available with interface of choice through a gateway, making use of industrial protocols like EtherCAT and Profinet. Data produced in this way can be used for predictive maintenance.

Ask advice
Flow scheme vacuum chamber
Example of process scheme with 6 Mass Flow Controllers. Shut-off valves are implemented to guaranty very low leak rate to the vacuum chamber

Do you need advice on gas flow control for reactive sputtering? Contact us

Please select the type of question you have
Do you have problems filling out this form? Please contact us by email ([email protected]).