One. Environmental requirements for vacuum coating.
Surface cleanliness of the substrate (wafer) during vacuum coating is crucial. Before entering the coating chamber, substrates should undergo thorough pre-coating cleaning to remove oil, dirt, and moisture.
Surface contamination on substrates comes from various substances, such as dust, lubricants, engine oil, polishing paste, grease, and sweat, that adhere to parts during processing, transportation, and packaging; oxide films formed on the surface of parts in humid air; and gases absorbed and adsorbed on the surface of parts. Vacuum coating manufacturers can generally remove these contaminants using degreasing or chemical cleaning methods.
Clean surfaces after cleaning should not be stored in the open air but should be stored in sealed containers or clean cabinets to minimize dust contamination. Storing glass substrates in freshly oxidized aluminum containers can minimize the adsorption of hydrocarbon vapors, as these containers preferentially adsorb hydrocarbons. Highly unstable surfaces that are sensitive to water vapor should generally be stored in a vacuum drying oven. Removing dust from the coating chamber, maintaining a clean workspace, and maintaining a high degree of cleanliness are fundamental environmental requirements for the coating process. In areas with high humidity, in addition to carefully cleaning the substrate and all components within the vacuum chamber before coating, baking and degassing are also necessary. To prevent oil from entering the vacuum chamber, pay attention to oil backflow from the oil diffusion pump, and implement oil-blocking measures for high-heating diffusion pumps.
Basic Principles of Coating and Film Coating
A. Raw Materials and Basic Principles:
The raw materials are generally resins, polymers, Teflon, silicone, acrylic acid, silicates, etc., but the auxiliary materials, formulations, and quantities vary. For example, the amount of emulsifier added varies, resulting in different emulsified states, ranging from water-like to milky and paste-like. After emulsification and demulsification, these substances partially penetrate or form a thin film.
B. Features and Differences of Vacuum Coating Machines:
Vacuum coating machines offer excellent penetration (depending on the particle size of the raw material) and superior surface smoothness. They are particularly suitable for European and American vehicle finishes with numerous pores, rough surfaces, heavy paint jobs, or hard finishes that require increased gloss.
Vacuum coating machines: Coating products contain film-forming additives and curing agents. Vacuum coating manufacturers create an instant film, which changes the properties accordingly.
