It is well known that the technology development trend of target materials is closely related to the film technology development trend of downstream application industry. As the technology improvement of application industry in film products or components, the target technology should also change. Such as Ic manufacturers. The recent development of low resistivity copper wiring is expected to greatly replace the original aluminum film in the next few years, so the development of copper target and the required barrier layer target will be urgent. In addition, in recent years, flat panel display (FPD) has largely replaced the cathode ray tube (CRT) based computer monitor and TELEVISION market. Also will greatly increase ITO target technology and market demand. In addition to the storage technology. The demand for high-density, high-capacity hard drives and high-density erasable CDS continues to increase. All of these lead to changes in the demand for target materials in the application industry. The main application fields of target materials and the development trend of target materials in these fields will be introduced respectively.
Among all the application industries, the semiconductor industry has the most demanding quality requirements for target sputtering films. Today 12-inch silicon wafers are manufactured. The width of the interconnects is decreasing. Wafer manufacturers require large size, high purity, low segregation and fine grains for the target, which requires the target to have a better microstructure. The crystal particle diameter and uniformity of the target have been considered as the key factors affecting the deposition rate of the film. In addition, the purity of the film is greatly related to the purity of the target material. In the past, 99.995% (4N5) copper target may be able to meet the 0.35pm process requirements of semiconductor manufacturers, but it cannot meet the current 0.25μm process requirements, and the 0.18um or even 0.13m process requirements of the non-meter. The required target purity will be above 5 or even 6N. Compared with aluminum, copper has higher resistance to electrical migration and lower resistivity, can meet! The conductor process requires submicron wiring below 0.25μm but brings with it other problems: low adhesion strength of copper to organic dielectric materials. And it is easy to react, resulting in corrosion of the chip's copper interconnect and circuit breaking. In order to solve these problems, a barrier layer needs to be set between the copper and the medium layer. The barrier material generally adopts the metal and its compounds with high melting point and high resistivity, so the thickness of the barrier layer is required to be less than 50nm, and the adhesion performance with copper and dielectric materials is good. The barrier materials for copper and aluminum interconnects are different. New target materials need to be developed. The targets used for the barrier layer of copper interconnection include tantalum, tungsten, TaSi, WSi, etc. But Ta and W are both refractory metals. It is relatively difficult to make, now we are studying molybdenum, chromium and other gold as an alternative material.
