The mechanical properties of the membrane layer are affected by the adhesion, stress, aggregation density, etc. From the relationship between the membrane layer material and process factors, it can be seen that if we want to improve the mechanical strength of the membrane layer, we should focus on the following process parameters:
(1) vacuum level. Vacuum on the performance of the film is very obvious. Most of the performance indicators of the film layer is very dependent on the vacuum level. Usually, as the vacuum degree increases, the film aggregation density increases, the firmness increases, the film structure is improved, the chemical composition becomes pure, but at the same time the stress also increases.
(2) Deposition rate. Improve the deposition rate not only can be used to improve the evaporation rate, that is, increase the evaporation source temperature approach, can also be used to increase the evaporation source area approach to achieve, but the use of the evaporation source to increase the temperature of the approach has its drawbacks: make the membrane layer stress is too large; film-forming gas is easy to decompose. So sometimes increase the evaporation source area than to improve the evaporation source temperature is more favorable.
(3) substrate temperature. Increase the substrate temperature is conducive to adsorption on the substrate surface of the remaining gas molecules to exclude, increase the substrate and the binding force between the deposited molecules: at the same time will promote the conversion of physical adsorption to chemical adsorption, enhance the interaction between molecules, so that the membrane layer structure is tight. For example, Mg, membrane, substrate heating to 250 ~ 300 ℃ can reduce the internal stress, improve the aggregation density, increase the hardness of the membrane layer: substrate heating to 120 ~ 150 ℃ prepared Zr03-Si02, multilayer membrane, its mechanical strength increased a lot, but the substrate temperature is too high will cause the membrane layer deterioration.
(4) Ion bombardment. Ion bombardment has an effect on the formation of highly cohesive surfaces, surface roughness, oxidation and aggregation density. The bombardment before coating can clean the surface and increase the adhesion; the bombardment after coating can improve the film layer aggregation density, etc., thus increasing the mechanical strength and hardness.
(5) Substrate cleaning. Substrate cleaning method is not appropriate or not clean, in the substrate residual impurities or cleaning agent, then cause new pollution, in the coating of different cohesion conditions and adhesion, affecting the first layer of the structural properties and optical thickness, but also make the film layer is easy to come off from the substrate, thus changing the characteristics of the film layer.
–This article is released by vacuum coating machine manufacturer Guangdong Zhenhua
Post time: May-04-2024