Tubular molybdenum target
In the production process of CIGS thin film solar cells or TFT-LCD flat displays, a film containing molybdenum layer is deposited by magnetron sputtering by a tubular target made of pure molybdenum and molybdenum alloys such as molybdenum niobium.
In the process of sputtering tubular molybdenum target, its properties have a key effect on the quality of sputtered films. At present, the main tubular molybdenum target manufacturers use powder metallurgy forming, extrusion, machining, binding process routes. Among them, the conditions of extrusion process equipment are high and the cost is large; The quality control of the binding process will be greatly improved with the increase of the length of the tubular molybdenum target.
Because the heat generated by magnetron sputtering cannot be lost in time, it has a great impact on the sputtering effect of the product. In the industry, the temperature of molybdenum tube is reduced by cooling water, but the cooling water will cause a certain degree of corrosion on the inner wall of the tube molybdenum target, which will affect the sputtering quality of the tube molybdenum target, and cause molybdenum metal pollution in the cooling water system. Therefore, indium and other metals are used in the industry to bind the stainless steel tube and molybdenum tube in the molybdenum tube, and after binding, circulating cooling water is passed in the stainless steel tube to reduce the use temperature of the molybdenum tube target. However, through application, it is found that after the increase of pipe length, the original binding method is easy to produce defects in the production process, and the binding welding rate and the maximum independent unwelded area area are more difficult to control, which is easy to produce off-target during customer use, affecting customer product quality and stable production. And the binding technology has high cost, complicated process and uneven heat dissipation effect, which limits the use of molybdenum tube target. Therefore, by spraying coating on the inner wall of molybdenum tube to improve the corrosion resistance of molybdenum tube in cooling water, it has become a reliable way to improve the performance of molybdenum tube.
