Molybdenum nickel base multielement alloy rotating target material and preparation method thereof
With the large-scale and high-precision of flat display, copper is used as the film material for the main wiring of the thin film transistor (TFT) of FPD driving components. Copper metallization has been widely developed in the TFT-LCD industry. In large-area high-frequency driving TFT LCD, due to the low adhesion of copper to the glass substrate. Therefore, copper needs to use a bonded metal film layer as the underlying or covering layer, such as Mo, Ti, Nb, Ni, Ta, Cr and other metal film layer. When different metals are placed in the etching solution with copper, a typical galvanic reaction occurs, and the copper is weakened or partially stained on the metal surface after drying, resulting in poor performance and display quality of the thin film transistor. So the oxidation resistance of metal film material and thermal stability, ease of etching and low impedance requirement is extremely high, the current use of molybdenum nickel molybdenum titanium or titanium alloy film on glass substrate with good adhesion, of indium tin oxide and silicon contact resistance is low, but because of containing titanium, titanium cannot very good dissolved in phosphoric acid, acetic acid, nitric acid solution, There is a risk of incomplete etch residue, which seriously affects TFT process quality. Compared with titanium, aluminum has good oxidation resistance, at the same time has good etching properties in the PAN, therefore, to improve the properties of TFT molybdenum alloy film, adding a certain amount of Al to form new alloy film layer (molybdenum nickel titanium alloy membrane layer), to ensure that you have good adhesion, oxidation resistance, heat resistance, low resistivity under the premise of the characteristics of easy to etch film. At present, there is relatively little research on the corresponding molybdenum nickel titanium aluminum alloy sputtering target. Because the utilization rate of the rotating target coating reaches about 75%, which is much higher than the utilization rate of the plane target of 30%, it will be very important for the preparation and development of molybdenum nickel titanium aluminum alloy rotating target, and the size of the target is getting larger and larger.
Because the melting point of molybdenum is as high as 2620℃, and the density is 10.2g/cm3, while the melting point of aluminum is 660℃, and the density is 2.7g/cm3, the melting point and density of the two are very different, the vacuum melting method is easy to shrinkage and segregation, can not guarantee the uniformity of the product structure and composition, and produce a variety of brittle phases, the product is easy to crack, can not prepare large size target material. If hot pressing sintering method is used to prepare the alloy, although the method can avoid segregation to a certain extent, but the hot pressing process can not remove oxygen, nitrogen and other gaseous impurities, will lead to the product impurities and oxygen content exceed the standard, resulting in the sputtering coating process arc striking; In addition, due to the limitation of hot pressing and sintering equipment, it is difficult to prepare target material with a length of more than 1.5 meters.
