Sputtering is one of the main techniques for preparing thin film materials. Bombarding the solid surface with accelerated ions, ions exchange momentum with the atoms on the solid surface, and make the atoms on the solid surface leave the solid and deposit on the base surface. This process is called sputtering. The bombarded solids are the source materials, usually called target materials, for depositing thin films by sputtering. Sputtering is a key process in semiconductor chip manufacturing, and the quality of sputtering target plays an important role in the quality of sputtering thin films.
Tantalum (Ta) is an important industrial metal material with a series of excellent properties, such as high melting point, good processing performance, corrosion resistance, low steam pressure and small expansion coefficient. In recent years, the application of tantalum in IC semiconductor chip manufacturing has attracted great attention. With the great scale development of integrated circuit, in deep sub-micron technology, copper will gradually replace aluminum metallized wiring on the silicon wafer materials, because the tantalum has high conductivity, high heat stability, and to the blocking effect of the atom, tantalum for copper with inert at the same time, between Cu and Ta not form chemical compounds, therefore tantalum as an ideal barrier to prevent the spread of copper. High purity tantalum has become a key structural material in IC manufacturing. At present, physical vapor deposition (PVD) is the main production method of diffusion barrier, and sputtering target is the key consumable material in this process. Therefore, tantalum sputtering target has an important application status in modern IC manufacturing. At present, high purity tantalum target has been widely used in China. The preparation of target tantalum plate mainly includes four aspects: purity, grain size, grain uniformity and grain orientation. The higher the purity of target material, small grains, the more (Ι Ο Ο mu PI ι below), the sputtering target material performance is better. With the increase of grain size, the film deposition rate decreases, and the more uniform the grain orientation distribution is, the better within the required grain size range. The better the uniformity of grain, the more uniform the thickness of the film deposited by the target. Within the appropriate grain size range, the plasma impedance of the target is low, the film deposition rate is high, and the film uniformity is good. Due to the high technical requirements for the preparation of high purity tantalum target materials, the production is difficult, especially in the high-end target materials market such as electronic devices, semiconductors and plane display, there is no mature preparation technology at present.
