Because molybdenum has the characteristics of high melting point, high conductivity, low specific impedance, good corrosion resistance and environmental protection, molybdenum target is widely used in the electronics industry, such as flat panel displays, thin-film solar cells, electrodes and wiring materials. Now let the editor and everyone know about the characteristics of molybdenum target in tungsten-molybdenum products?
1. High-purity molybdenum target
The higher the purity of the molybdenum target, the better the performance of the sputtered film. Generally, the purity of molybdenum sputtering target is required to reach at least 99.95%. However, with the continuous improvement of the scale of glass substrates in the LCD industry, the length of wiring is required to be extended and the line width is required to be thinner. In order to ensure the uniformity of the film and the quality of the wiring, the purity requirements of molybdenum sputtering target are also improved accordingly. Therefore, according to the scale of the sputtered glass substrate and the application environment, the purity of molybdenum sputtering target is required to be 99.99%-99.999% or even higher.
2. High-density molybdenum target
During the sputtering coating process, when the sputtering target with low density is bombarded, the gas in the internal pores of the target is suddenly released, resulting in large-scale target particles or microparticles splashing, or after the film is formed, the film is bombarded by secondary electrons to form microparticles splashing. The appearance of these particles will reduce the quality of the film. In order to reduce the pores in the target solid and improve the performance of the film, the sputtering target is generally required to have a higher density. For molybdenum sputtering targets, the relative density should be above 98%.
3. Grain size
Generally, molybdenum sputtering targets are polycrystalline structures, and the grain size can range from microns to millimeters. Experimental studies have shown that the sputtering rate of fine-scale grain targets is faster than that of coarse grains, and the thickness distribution of deposited films is more uniform for targets with smaller grain size differences.
4. Crystallization direction
During sputtering, the target atoms are simply preferentially sputtered along the direction of the hexagonal arrangement of atoms. Therefore, in order to achieve the sputtering rate, the sputtering rate is often increased by changing the target crystal structure. The crystallization direction of the target also has a great influence on the thickness uniformity of the sputtered film. Therefore, obtaining a target structure with a certain crystal orientation is crucial to the sputtering process of the film.
5. Thermal and electrical conductivity
Tungsten and molybdenum product manufacturers tell you that before sputtering, the molybdenum sputtering target must be connected with the oxygen-free copper (or aluminum and other materials) chassis to ensure that the thermal and electrical conductivity of the target and the chassis are good during the sputtering process. After binding, it is necessary to pass ultrasonic inspection to ensure that the non-bonding area between the two is less than 2%, so as to meet the requirements of high-power sputtering without falling off.
6. Molybdenum target performance
Purity: pure molybdenum ≥99.95%, high temperature molybdenum ≥99% (with added rare earth elements)
Density: ≥10.2g/cm3
Melting point: 2610℃
Specifications: round target, plate target, rotating target
Applicable environment: vacuum environment or inert gas protection environment, the pure molybdenum in tungsten-molybdenum products is higher, high temperature resistance 1200 degrees, molybdenum alloy is higher and high temperature resistance 1700 degrees.