Tungsten-Molybdenum Alloy Rotating Target

TFT film has the advantages of high responsivity, high brightness and high contrast. It is one of the basic materials in many industries. Therefore, it is widely used in the fields of solar cells, liquid crystal displays and plasma displays. In recent years, along with the rapid development of high-end displays, tungsten molybdenum alloy rotating target is an important material for preparing TFT film.

At present, plate target coating is widely used in industry, its disadvantage is that the thickness uniformity of film deposition is not easy to control, the utilization rate of flat target is low, only 20 ~30%, and the utilization rate of rotating target can reach more than 80%. But at present, few manufacturers can produce qualified TFT rotating targets, most of which are in the R & D stage. The key technical difficulty of TFT rotating target is to control the problem of cracking and low density during the molding process, and to control the uniformity of the shrinkage of TFT rotating target during the sintering process.

In order to solve the above technical problems, some scholars have provided a method for producing a tungsten-molybdenum alloy rotating target, which is suitable for the production of a large-area TFT film, and the process contents are as follows:

Step 1, the tungsten powder with the theoretical density above 98% and the average particle size of 7 m, and the molybdenum powder with the theoretical density above 98% and the average particle size of 10 mu m are respectively mixed and prepared under the condition of the rotational speed of 80 r/min according to the mass ratio of 5:5.

Step 2: arbitrarily select five points in the material after the step 1 to detect the tungsten content and the molybdenum content until the tungsten-molybdenum content ratio error of each detection point is between 0.01 and 0.05%, and the mixing is completed, and the standby is performed;

Step 3, the mixture after the second step is mixed through a 200 mesh sieve, and used;

Step 4, the mixed material treated by step three is filled to the rubber sleeve with a tubular flexible mold, and molybdenum disulfide powder is applied to the contact surface of the mold and the mixture material, then the rubber sleeve is sealed after the vacuum is sealed, and the rubber sleeve after the vacuum is placed on the cold static press, and the initial pressure is 20~50MPa. At the same time, the rough billet is formed and the rough billet is made two times under the condition of 50-200MPa, until the density of the billet reaches 62% of the theoretical density, which is unloaded to normal pressure and spare.

Step 5, the green tungsten-molybdenum alloy target green body pressed in step 4 is placed in a vacuum hot-pressing sintering furnace, and hot-pressed and sintered under the condition of a hydrogen atmosphere under the pressure of 30 MPa and a temperature of 1350 ° C, and the heat preservation pressure is 5 hours. After that, the mold is demolded at 1000 ° C by a high-temperature demolding process, and cooled to room temperature to obtain a crude tungsten-molybdenum alloy target, which is ready for use;

Step 6, the crude tungsten-molybdenum alloy target obtained in the step 5 is mechanically processed to a desired size, and then placed in a vacuum annealing furnace, and heated to 1600 ° C for 2 h, and used;

Step 7, perform chemical and physical testing on the crude tungsten-molybdenum alloy target processed in step six, and then ultrasonically clean the target to achieve acceptable roughness and reserve;

Step 8, pick up the mixed material after the step three, mix the material into the ball mill, mill 3h, and screen the tungsten and molybdenum spray powder over 1000 mesh.

Step 9, spraying the tungsten-molybdenum spray powder prepared in the eighth step onto the outer surface of the step 7 by using a plasma spraying method under an inert gas atmosphere;

Step 10, the target cavity prepared in the step IX is vacuumed, and then an inert gas is introduced therein, the gas flow rate is 1000 SCCH, and the tungsten-molybdenum spray powder obtained in the step 8 is cooled under an inert gas atmosphere. Sprayed into the cavity of the target and sprayed to a thickness of 0.2 mm to obtain a product.

The above process is simple and stable, which not only greatly reduces the production cost of the rotating target, but also has excellent properties such as uniform microstructure and high thermal shock resistance, and is suitable for the production of large-area TFT films.

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