Surface Morphology And Sputtering Performance Of Cu Targets With Different Grain Sizes For Magnetron Sputtering

In recent years,semiconductor-related industries with integrated circuits as the main direction have developed rapidly.The progress of integrated circuit circuit technology is inseparable from the gradual improvement of the semiconductor manufacturing process,and the magnetron sputtering technology,as an important link in the semiconductor production and manufacturing,its process needs continuous improvement.As the main material source of the magnetron sputtering film,the performance of the target directly affects the quality of the deposited film.How to affect the sputtering performance and even the quality of the coating by changing the performance of the target has always been the focus of attention in the field of vacuum coating.The production of targets has a variety of technical indicators,but the research on the relationship between each target of the target and the sputtering performance of the target and the deposition performance of the coated film is not sufficient,and a single indicator is difficult to be compared with the complex sputtering and deposition performance.The thin film process produces a direct connection,which is the main difficulty in target research.In this paper,the effects of target grain size on sputtering morphology,target voltage during sputtering,sputtering yield and even film thickness distribution and crystallization were studied for copper targets and copper test blocks with different grain sizes and surface morphology.The relationship between the original copper surface and the surface morphology and its changes during sputtering was explored,and the relationship between the target surface morphology and sputtering performance was established,which was the grain size and surface roughness during the target production process.The choice of degree provides the basis.The study found that the grain size of the target will significantly affect the sputtering morphology and roughness of the target surface.The sputtering morphology roughness of the30μm target is 5.601μm,and the surface is relatively dense.is 8.470μm and looser.Moreover,the topography of the target surface will significantly affect the target voltage and even the I-V characteristic curve under the same target current during sputtering.The smaller the average peak spacing of the original surface profile of the target material,the higher the target voltage.When the average peak spacing is 27.223μm,the target voltage is 490 V,and when the average peak spacing is 100.000μm,the target voltage is 420 V,this is because the smaller the average peak spacing is,the stronger the recapture effect of the target surface on the secondary electrons generated by the Ar~+bombardment is,and the lower the actual output of secondary electrons exiting the target surface,a higher target voltage is required to maintain the same target current.The study also found that the sputtering mechanism of grains on the target surface is mainly grain boundary preferential sputtering.The initial sputtering of the grains on the target surface mainly occurs at the grain boundaries,forming a sputtering etching slope around the grains.Forms conical protrusions.As the sputter etching continues,the volume of the bump will continue to decrease until it disappears and the underlying die is exposed.The original surface topography of the target also affects the sputtering process of the target.For the original grinding surface,due to the large number of surface defects,a large number of protrusions are formed on the surface after sputtering.These protrusions require a relatively long time of 400 s to be etched and basically disappear,which makes the grinding of the rough copper block.The chipped surface becomes fully sputtered.For the polished copper test block,only a few small bumps are formed on the surface after sputtering,these bumps can be completely etched and disappeared in a short time of 150 s sputtering,and the formed and ground surfaces are fully sputtered After the same sputtering morphology.In the coating research of targets with different grain sizes and surface roughness,it is found that the grain size of the target has little effect on the sputtering yield,and mainly affects the sputtering yield by affecting the target voltage under the same target current.The grain size of the target has a great influence on the thickness distribution of the film.The ideal flat target surface has the highest deposition rate at the position where the substrate is facing the center of the target.The deposition rate is not necessarily the highest,but it basically conforms to the rule that the larger the eccentricity of the deposition position of the ideal flat target,the lower the deposition rate.The crystallization of the plated film has little to do with the thickness of the film,but is related to the location of deposition.The smaller the bias current,the smaller the crystal grain of the film.