Vacuum evaporation glove box (abbreviated as evaporation) is a glove box technology that has been developed early and has a wide range of technical applications in PVD professional skills. Although sputtering and ion plating, which were developed later, have advantages over evaporation in many aspects, there are still many advantages in vacuum evaporation expertise, such as the relative simplicity of special equipment and processing technology, which can produce very pure plating. The film layer, and the preparation of the film layer with special structure and properties, etc., are still very important glove box professional skills. In recent years, due to the wide application of professional skills such as electronic bombardment transpiration, high-frequency induction transpiration and laser transpiration in transpiration glove box professional skills, this professional skill has become increasingly perfect.
Place the membrane in the vacuum glove box and use the evaporation source to heat it to evaporate. When the mean free path of the evaporated molecules is greater than the linear scale of the vacuum glove box, the atoms and molecules of the vapor escape from the surface of the evaporation source. Blocked by the impact of other molecules or atoms, it can directly reach the surface of the substrate to be plated. Due to the low temperature of the substrate, it condenses on it to form a film. In order to improve the adhesion between the evaporated molecules and the substrate, the substrate Proper heating is required. In order to make the evaporation glove box go smoothly, it should have the vacuum conditions during the evaporation process and the evaporation conditions during the film making process.
Vacuum conditions in the evaporation process: When the mean free path of vapor molecules in the vacuum glove box is greater than the distance between the evaporation source and the substrate (called the vapor distance), sufficient vacuum conditions will be obtained. Therefore, it is necessary to increase the mean free path of the remaining gas and reduce the collision probability between the vapor molecules and the remaining gas molecules. It is necessary to pump the vacuum glove box into a high vacuum.
In the vacuum glove box process, the higher the vacuum degree, the better, because when the vacuum degree in the vacuum glove box room exceeds 10-6Pa, it is necessary to bake the vacuum system to achieve it. Because baking and degassing will cause contamination of the substrate, the film can be formed under high vacuum of 10-5 Pa without baking and degassing. The quality of the film is not necessarily better than that of the film prepared under ultra-high vacuum. The poor quality is worth noting. Therefore, in vacuum transpiration glove box equipment, the vacuum degree selected for the glove box room should generally be higher than 10-2Pa and lower than 10-5Pa.