What are the main performance requirements for silicon sputtering targets?
Silicon sputtering target purity
Purity is one of the main performance indicators of silicon sputtering targets because the purity of the sputtering target has a great effect on the properties of the film. However, in practical applications, the purity requirements for silicon sputtering targets are not the same. For example, with the rapid development of the microelectronics industry, wafer size from 6 ", 8" to 12 ", and the wiring width from 0.5um reduced to 0.25um, 0.18um or even 0.13um, before 99.995% of the silicon sputtering The purity of the target can meet the requirements of 0.35umIC process, and the preparation of 0.18um line on the purity of silicon sputtering target requires 99.999% or even 99.9999%.
Silicon sputtering target Impurity content
Silica sputtering The impurities in the target solids and the oxygen and moisture in the pores are the main source of contamination for the deposited film. The requirements for different impurity content of silicon sputtering targets for different purposes are also different. For example, the semiconductor industry for pure aluminum and aluminum alloy sputtering target, the alkali content and radioactive element content has special requirements.
Silicon sputtering target density
In order to reduce the porosity of the silicon sputtering target solids and improve the performance of the sputtered film, it is generally desirable for the silicon sputtering target to have a higher density. The density of the sputtering target not only affects the sputtering rate, but also affects the electrical and optical properties of the film. The higher the density of the silicon sputtering target, the better the performance of the film. In addition, increasing the density and strength of the silicon sputtering target allows the silicon sputtering target to better withstand thermal stress during sputtering. Density is also one of the key performance indicators of silicon sputtering targets.
Silicon sputtering target Grain size and grain size distribution
Usually the sputtering target is a polycrystalline structure with a grain size in the order of microns to millimeters. For the same kind of silicon sputtering target, the sputtering rate of the fine silicon sputtering target is faster than that of the coarse silicon sputtering target. The sputtering rate is small (uniform distribution) The thickness distribution of the deposited film is more uniform.