Substrate Preparation

Cleanliness and preparation of substrates is essential for success in thin film work. Condensation rate and adhesion of the deposit are critically dependent of conditions on the surface. Even a thin layer of grease can have such a gross effect on a molecular scale as to alter completely the characteristics of the layer.

Where possible substrates and optical components are cleaned in an ultrasonic bath with an alkali based cleaner. Then are they rinsed in hot water and submerged in isopropyl alcohol to prevent water marks. Drying and dust removal finally makes them ready for the coating process. Any slight marks found on the substrates mean that the whole process must be repeated. After cleaning, the items are secured in special jigs, this stops any movement of the piece and vibration from the coating plant affecting the coating. Any jigs that are not held in house are manufactured when required.

Optical cleaning in the Thin Film Facility