Among all application industries, the semiconductor industry has the most demanding requirement on the quality of target sputtering film. 12-inch silicon wafers have now been manufactured. The width of the interconnect is decreasing. Silicon wafer manufacturers require large size, high purity, low segregation, and fine grain, which requires a better microstructure. The crystal particle diameter and uniformity of the target material have been considered as the key factors affecting the film deposition rate. In addition, the purity of the film has a great relationship with the purity of the target material. In the past, 99.995% (4N5) purity copper target may be able to meet the process requirements of 0.35pm of semiconductor manufacturers, but it cannot meet the process requirements of 0.25um, while the 0.18um} technology or even 0.13m process without meters requires the target material purity to reach 5 or even more than 6N. Compared with aluminum, copper has higher resistance to electromigration and lower resistivity, which can be satisfied! The conductor process requires submicron wiring of less than 0.25um, but this brings with it other problems: the low adhesion strength of copper to organic dielectric materials. And it is easy to react, which leads to the copper interconnection of the chip being corroded and broken in the process of using. In order to solve these problems, a barrier layer needs to be set between the copper and the dielectric layer. Barrier layer materials generally adopt metal and its compounds with high melting point and high resistivity. Therefore, the barrier layer thickness is required to be less than 50nm, and its adhesion performance with copper and dielectric materials is good. Copper and aluminum interconnect barrier materials are different. New target materials need to be developed. Target materials for copper interconnect barrier layer include Ta, W, TaSi, WSi, etc. But both Ta and W are refractory metals. Production is relatively difficult, and now is studying molybdenum, chromium and other taijin as an alternative material.
Flat panel displays (FPD) have significantly impacted the crt-dominated computer displays and TV markets over the years, and will also drive the technology and market demand for ITO target materials. Today, there are two types of iTO targets. One USES indium oxide in nanometer state mixed with tin oxide powder and sintered, the other USES indium tin alloy target material. Indium tin alloy target can be used to produce ITO thin films by dc reactive sputtering, but the target surface will oxidize and affect the sputtering rate, and it is not easy to get large size taijin target. Nowadays, the first method is generally adopted to produce ITO target materials, and L}IRF reactive sputtering coating is used. It has a fast deposition rate. And can accurately control the film thickness, high conductivity, film consistency, and substrate adhesion strong advantages l. But target materials are difficult to make because indium oxide and tin oxide do not easily sinter together. Generally, ZrO2, Bi2O3 and CeO are adopted as sintering additives to obtain target materials with a density of 93%~98% of the theoretical value. The properties of ITO films formed in this way are greatly related to the additives. Japanese scientists used Bizo as additive, Bi2O3 cr melts in 820, in l500 ℃ sintering temperature is beyond the part has been volatile, so in the liquid phase sintering conditions to obtain relatively pure ITO target materials. Moreover, the oxide material needed is not necessarily nanoparticles, which can simplify the previous process. The resistivity of ITO films obtained from such targets is 8. 8%. 1 10n-cm, near pure ITO film resistivity. The size of both FPD and conductive glass is quite high, and the width of conductive glass can even reach 3133. In order to improve the utilization rate of target materials, ITO targets of different shapes, such as cylindrical ones, are developed. In 2000, the national development planning commission and the ministry of science and technology included ITO large targets in the guidelines on key areas of the information industry that are currently under priority development.
