Study On Production Technology And Sputtering Properties Of Pure Mo Target Of TFT-LCD

In modern TFT-LCD manufacturing, molybdenum is mainly used in Al barrier film, partly in Cu barrier film. Requirements for TFT-LCD conductive film are low resistivity, good uniformity, smooth appearance, good adhesion, good step coverage, minimum stress, minimum protrusion, minimum electron mobility and etc. What molybdenum target can meet the conductive film requirements of TFT-LCD, and how can prepare molybdenum target with excellent sputtering properties become difficult, it become the focus of molybdenum target researchment. In the paper, the purity of molybdenum powder is 99.99%. Powder metallurgy preparation technology of molybdenum target and its magnetron sputtering properties are systematiclly researched. The researching contents and results are as follows.The influencing factors of cold isostatic pressing for molybdenum powder are studies. Uniform dispersion, d(0.5) less than 10 ?m molybdenum powder can be pressed into plates with uniform microstructure; But molybdenum powder with massive agglomeration is compacted easily to form the "arch effect". when the isostatic pressure is greater than 200 MPa, pressing pores are little and small in compacting blanks. When molybdenum powder fisher particle size is 3.5 ?m, loose loading density is higher than 1.2g/cm3, loading powder density is uniform, compacting shrinkage is homogeneous. "Swing type powder filling method" and "pier loading powder method" are put forward. High density slab can be prepared by high pressure pressing.They are discussed that sintering influence factors and sintering mechanism of molybdenum target. Sintering densification velocity of 400 MPa pressing slab is faster than that of 100 MPa, 200 MPa and 300 MPa. In order to reduce sintering temperature and get fine grain, high pressure pressing and low-temperature sintering method can be adopted. Sintering heating rate for 100 MPa pressing slab can use 3K/min and 400 MPa pressing slab can adopt 1K/min. At initial sintering stage of 1273K~1673K, surface diffusion is dominant; at middle sintering stage of 1773K~1973K, molybdenum powder particles begin to bond, grains begin to move, porosity and stomata closure time is a linear relationship, shrinkage rate is maximum, densification is faster; at sintering late stage of 2073K~2173K, gas holes shape into solitary spherical closed pores, grains grow up, blank shrinkage ratio is up to 90%~100% and close to theoretical density.How different plastic working methods influence on molybdenum target structure are Studied. Forging combining with rolling molybdenum target grains are more uniform and finer than rolling alone. Forging and rolling cogging molybdenum target texture are {100} <011>, {111} <112>, {111} <110>.Researching molybdenum target microstructure effect on sputtering films showes that sputtering thin film crystallization degree and square resistance are better than that of other deformation ratio target when plastic deformation amount is 80%. When deformation amount is 80%, annealing temperature is 1373 K and 1473 K, molybdenum target sputtering film roughness is less than 21 nm, thickness uniformity is good. Molybdenum target with grain size of less than 50 ?m, target sputtering speed is uniform, sputtering thin film resistance deviation is less than 10%; preferred orientation of molybdenum target sputtering thin film is(110).