Physical vapor deposition (PVD) is one of the most critical processes in the production of semiconductor chips. Its purpose is to deposit metal or metal compounds on silicon wafers or other substrates in the form of thin films, and then through the coordination of lithography and etching, the complex wiring structure of semiconductor chips is finally formed. Physical vapor deposition is accomplished by sputtering machine, and sputtering target is a very important consumable material used in the above process. Common sputtering targets include high purity Ta, and non-ferrous metals such as Ti, Al, Co and Cu. The production of sputtering targets evolved at the same time as the semiconductor production process, so information on their production techniques and applications is extremely rare. In addition, due to the high investment, high risk and high competitiveness of semiconductor technology, the technical and market information of the target material closely related to its competitiveness (determined by cost and technology) is extremely confidential. Forging method of large size tantalum target.
With the rapid development of semiconductor technology, the integration degree is higher and higher, monocrystalline silicon chip integrated device for exponential growth per unit area, but also more and more big, silicon wafer size wiring width more and more thin, therefore the demands of the size of sputtering target materials is becoming more and more big, also calls for more refined microstructure, the forefront of the semiconductor technology is 12 "wafer very large scale integrated circuit manufacturing technology. 8 "target is the target needed to produce 8" wafer. Although the world's leading edge of semiconductor integrated circuit is 12 "wafer 90nm technology, 65nm, 45nm, 32nm technology is under development, China's current large-scale production is represented by SMIC is 8" wafer 0.13-0.18um (130_180nm) technology. As the chip size (8 inches) increased from 200 mm to 300 mm (12 inches) and the corresponding pie shoot Dr. Gerba material size must increase in order to meet the basic requirements of PVD coating, at the same time, the line width from (130-180 nm) reduce to 90 _45nm, based on the electrical conductivity of the conductor and matching performance of barrier layer, the sputtering target materials will also be from ultra high purity Al/Ti system into ultra high purity Cu/Ta, Ta in semiconductor sputtering target material industry the importance of more and more big, at the same time demand is also more and more big. After sputtering on silicon film thickness uniformity, it is very important for the final product, depending on the internal structure and texture orientation of tantalum target, uniform grain size, grain crystallization orientation towards the same target, will cause the sputtering grain sputtering in the sputtering rate reaching the same trajectory approaching the same distribution, sputtering atom Angle, so that you will get uniform coating film thickness, and at the same time of tantalum target material utilization rate is greatly increased. At present, the technology of producing large size tantalum targets (8 "or 12") is still in the immature stage in China. The main disadvantage of the existing technology is that for large size ingot (diameter > 200mm), the original grain can not be broken effectively and uniformly after forging, resulting in defects such as crystal strip and uneven grain size.
