Study On Preparation And Repair Of W-10Ti Alloy Targets By Spark Plasma Sintering(SPS)

W-10Ti thin films are widely used in the field of integrated circuits because they can effectively prevent Cu interconnects from diffusing to Si or Si O₂ substrates and have good adhesion to chips.W-10Ti films are usually prepared by magnetron sputtering,and the quality of the films is controlled by the quality of W-10Ti alloy target.The W-10Ti target with high density,high purity,uniform structure and less Ti rich phase was prepared and repaired by studying the effects of spark plasma sintering(SPS)process on the microstructure,mechanical properties,physical properties and sputtering coating properties of the alloy.The main conclusions are as follows:(1)The large-scale commercial W-10Ti new target and its waste target were characterized by 3D scanner in order to obtain the digital model of its geometry.The Vickers hardness,density,thermal conductivity and electrical conductivity of new and waste targets at different positions(core,middle and edge)were measured.The microstructure,phase composition,grain size and Ti-rich phase content was characterized by XRD,SEM and EDS.The performance index library of W-10Ti target was constructed;(2)The effects of SPS sintering temperature and dwelling time on the properties of W-10Ti target were studied.The process parameters are:sintering temperature ranges of 1400-1700?,dwelling time ranges of 0-30 min,axial pressure 30 MPa and heating rate of 90-100?/min.The W-10Ti target consists of?-W(Ti)main phase and a fractional?-Ti(W)phase.The content of Ti-rich phase decreases with the increase of sintering temperature,and the content is the lowest at 1600?.With the extension of dwelling time,the content of Ti-rich phase first decreases and then increases,and the minimum value is 3.04±0.65%at 15 min.The density increases with the increase of sintering temperature,increases at first,and then decreases slightly with the increase of dwelling time.The threshold value is 15 min.Vickers hardness is not sensitive to the change of process parameters,and it is maintained at 575.80-618.08 at 1 kg N.The thermal conductivity decreases with the increase of sintering temperature,decreases first and then increases with the increase of dwelling time,and reaches the minimum value at 1600?for 15 min.The statistical results of grain size show that the grain growth is not obvious at lower temperature(1400-1500?),but it is obvious at higher temperature(1600-1700?).The calculated grain growth index n=2 indicates that the grain growth mechanism of W-10Ti powder sintered by SPS is grain boundary diffusion in the range of 1400-1700?.The calculated activation energy Q of grain growth is57.48±8.42 k J mol^-1(5 min),49.21±10.91 k J mol^-1(15 min)and 61.46±8.17 k J mol^-1(30 min).According to the experimental results of microstructure and properties,the sintering temperature of 1600?and dwelling time of 15 min are the best parameters,which should be set as the process parameters for subsequent target repair.(3)The W-10Ti alloy targets with diameters of 25 mm,50 mm and 75 mm were successfully repaired by SPS method.The test results of the three sizes of target materials show that the microstructure of the core and edge of the repaired target is uniform,and the performance is stable;meanwhile,compared with the waste target.The content of Ti-rich phase in the repaired target is greatly reduced,and the Vickers hardness,density and grain size are increased,and the thermal conductivity is decreased.Compared with the film sputtered by the original target,the film sputtered by the repaired W-10Ti target has smoother surface,fewer cracks,the same particle size and no suspended particles,which can meet the standard for using.