Purity is one of the main performance index of the target, because the purity of zirconium target has great effect on the performance of thin film. But in the practical application, the requirements of purity to target are not same. For example, with the rapid development of micro electronic industry, wiring width reduced from 0.5um to 0.25um, 0.18um, even 0.13um, in the past, 99.995% target purity can meet requirements of the process of 0.35umIC, and the purity requirement of zirconium target of making 0.18um lines is 99.999% or even 99.9999%.
The impurity content:
The impurities of target solid and the oxygen and water vapor of target pores are the main pollution source of the deposited films. The different uses of the Zr target are also different to the requirements of different impurity content. For example, pure aluminum and aluminum alloy target used in the semiconductor industry have special requirements to content of alkali metal and radioactive elements.
The density:
In order to reduce blowhole in target solid, improve the performance of the sputtered films, the target is usually required with a higher density. The density of Zr target not only affects the sputtering rate, but also affects the electrical and optical properties of the films. The higher of target density, the better the performance of the film. In addition, improving the target density and intensity can make the target well withstand the thermal stress in the sputtering process. Density is also one of the key performance index of the target.
