Because molybdenum has a high melting point, high electrical conductivity, low specific resistance, and good corrosion resistance and environmental protection, molybdenum targets are widely used in the electronics industry, such as flat panel displays, thin-film solar cells, Wire material, Sifeng Xiaobian will introduce you the characteristics of molybdenum target.
1.High purity
The higher the purity of the molybdenum target, the better the performance of the sputtered film. Generally, the purity of the molybdenum sputtering target needs to be at least 99.95%. However, as the size of glass substrates in the LCD industry continues to increase, the length of wiring and the width of wires have to be reduced. In order to ensure the uniformity of the film and the quality of the wiring, the requirements for the purity of molybdenum sputtering targets have also increased accordingly. Therefore, according to the size of the sputtered glass substrate and the use environment, the purity of the molybdenum sputtering target is required to be 99.99% -99.999% or higher.
2.High density
During the sputtering coating process, when a relatively dense sputtering target is bombarded, a large-sized target particle or particle splashes due to the sudden release of gas existing in the pores inside the target, or the film is subjected to Sub-electron bombardment causes particles to splash, and the presence of these particles will degrade the film quality. In order to reduce the pores in the target solid and improve the film performance, the sputtering target is generally required to have a high density. For molybdenum sputtering targets, the relative density should be above 98%.
3.Grain size
Generally, the molybdenum sputtering target has a polycrystalline structure, and the grain size can be on the order of micrometers to millimeters. Experimental studies have shown that the sputtering rate of fine-grained targets is faster than that of coarse-grained targets, and the thickness distribution of the deposited films is more uniform for targets with smaller grain size differences.
4. Crystallization direction
Because the target atoms are easily sputtered along the direction of the hexagonal close arrangement of atoms during sputtering, in order to achieve the sputtering rate, the sputtering rate is often increased by changing the crystal structure of the target. The crystal orientation of the target also has a large effect on the thickness uniformity of the sputtered film layer. Therefore, obtaining a target structure with a certain crystal orientation is very important for the sputtering process of the thin film.
5, thermal conductivity
Generally, the molybdenum sputtering target must be connected with the oxygen-free copper (or other materials) chassis before sputtering, so that the target and the chassis have good thermal conductivity during the sputtering process. After the binding, the ultrasonic inspection must be performed to ensure that the uncombined area of the two is less than 2%, so as to meet the requirements of high-power sputtering without falling off.
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