Process Gas Flow Control in Glass Coating Systems

Glass coatings are made for modifying optical properties of glass, to improve solare transmission characteristics or just for changing its aesthetic appearance. Wether for solar and energetic control or architechtural purposes only, glass coating is very demanding process.

Superior layer uniformity, high yields and reduced cost of ownership are among the demands of the Glass Coating Industry. By individually controlling process gas segments, film thickness uniformity improvements are achieved. Additionally, if the control is made by instruments capable of securing a stable flow profile, reproducibility and fast response time, optimal perforemance can be reached. In order to reduce the cost of ownership, instruments must be reliable and endure working 24 hours a day, 7 days a week,

Sputting is a physical vapor deposition (PVD) process which involces bombarding the coating material(target) with gas ions under high voltage accelearation, in order to promote the ejection of atoms from the target. The ejected atoms will be propelled towards the substrate, forming a thin-film coating over its surface. Plasma Enhanced PVD, like magnetron sputtering, is considerd to be the most efficient technology. For this process an inert gas is required: Argon is the most commonly used, however some sputtering processes may involve oxide or nitride film coating; if so O₂ and /or N₂ are added to the insert sputtering gas. 

According to its nature, the process requires low pressure. Nevertheless, the process gas flow must be sufficient for allowing the ionic bombardment process to take place, otherwise it becomes improssible to maintain the plasma. Hence, the process gas flow must be meticulously controlled. If not, the quality and optimal homogeneity of the coating may be severely compromised. Due to its unique proportional electromagnetic control valve, Bronkhort High-Tech mass flow controllers are ideal for this application. The instruments allow simultaneously an extremely fast and smooth control, providing excellent stability and repeatability.

For attaing thin-film coatings compliant with the highest quality standards the process gas system must be capable of providing superior layer uniformities. Easy maintenance is also a major concern when lare area coaters are involved. Bronkhorst fully understands the Glass Coating Industry's demands and has therefore developed sophisticated solutions specially addressed to meet the demands of state of the art large area glass coating applications.