Purity is one of the main properties of target materials, because the purity of the target material has great effect on the performance of the film. However, the purity requirements of the target materials are different in practical application. For example, with the rapid development of microelectronics industry, silicon wafer size from 6 ", 8" development to 12 ", while the wiring width from 0.5um to 0.25um, 0.18um or even 0.13um, the previous 99.995% of the target purity can meet 0. The process requirements of 35umIC, and the preparation of 0. The purity of the 18um line on the target requires 99.999% or even 99.9999%.
The impurities in the target solid and the oxygen and water vapor in the pores are the main pollution sources of the deposited films. Target materials for different purposes are different in requirements for different impurity content. For example, the semiconductor industry of pure aluminum and aluminum alloy target materials, alkali metal content and the content of radioactive elements have special requirements.
In order to reduce the porosity in the solid of target material and improve the performance of sputtering film, the target material has high density. The density of the target material affects not only the sputtering rate, but also the electrical and optical properties of the film. The higher the target material density, the better the performance of the film. In addition, increasing the density and strength of the target material can better withstand the thermal stress in the sputtering process. Density is also one of the key performance indexes of target materials.
Grain size and grain size distribution
The target is usually polycrystalline structure, and the grain size can be from micron to millimeter. For the same target, the sputtering rate of fine grain targets is faster than that of coarse grains, and the thickness distribution of the films deposited by target sputtering with smaller grain size is even more uniform. Baoji Deep Dahua Titanium Industry Co., Ltd. specializes in silicon aluminum tube.