Views:2 Author:Site Editor Publish Time: 2017-06-28 Origin:Site
The purity is one of the main performance indexes of the sputtering target, because the purity of the target material has a great influence on the performance of the film.However, in practical application, the requirements for the purity of the target material are not the same.For example, with the rapid development of microelectronics industry, silicon wafer size from 6 ", 8 to 12 "development", and the wiring width from 0.5 um reduce to 0.25 um, 0.18 um and 0.13 um, 99.995% of the target material before can satisfy the technological requirements of 0.35 umIC purity, and the preparation of 0.18 um lines for the purity of target insist on 99.999% or 99.999%.
The oxygen and water vapor in the impurities and pores in the solid are the main sources of deposition.Different target materials have different requirements for different impurities.For example, the pure aluminum and aluminum alloy targets used in the semiconductor industry have special requirements on alkali metal content and radioactive element content.
In order to reduce the stomata in the solid of the target material and improve the performance of the sputter film, the target material is usually required to have higher 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 film performance.In addition, the density and strength of the target material can better withstand the thermal stress during the sputtering process.Density is also one of the key performance indicators of the target material.
Grain size and grain size distribution
Usually the target material is polycrystalline structure, and the grain size can be from micrometer to millimetre.For the same target, the sputtering rate of the tiny target is faster than that of the larger target.The thickness distribution of the pellets is more evenly distributed.