Views:3 Author:Site Editor Publish Time: 2017-09-06 Origin:Site
Purity is one of the key performance indicators in the target, because a great impact on the purity of the target thin film properties. However, in practice, on target purity requirements are not the same. For example, with the rapid development of the microelectronics industry, wafer sizes from 6 ", 8" development to 12 ", and the wiring width is reduced from 0.5um to 0.25um, 0.18um or 0.13um, previously a target purity of 99.995% 0.35umIC meet process requirements, and the preparation of the lines on the target 0.18um require 99.999% purity or 99.9999%.
Target solid impurities and pores of oxygen and water vapor is the main source of the deposited film. Targets for different purposes for different impurity content requirements are also different. For example, aluminum and aluminum alloy target material used in the semiconductor industry, alkali metal content and the content of radioactive elements have special requirements.
In order to reduce the porosity of solid target to improve the performance of the sputtering film, generally require a relatively high density target. The density of the sputtering target not only affects the rate, but also affect the electrical and optical properties of the film. The higher the density of the target, the better the properties of the film. Furthermore, to improve the density and strength of the target so that the target can better withstand the thermal stress during the sputtering process. Density is one of the key performance indicators targets.
Grain size and grain size distribution
Usually the target of a polycrystalline structure, grain size can be microns to millimeters. For the same target, fine grain sputtering rate than the coarse grains target sputtering targets faster rate; the difference is small grain size (distribution) target sputtering deposition of thin film thickness distribution is more uniform.