Effect Of Plastic Deformation And Heat Treatment On The Recrystallization Of High Purity Al-1%Si Alloy

In this research,the effect of thermal mechnical process on recrystallization process was studied.High purity Al-1%Si is one of the important key material for semiconductor integrity chips process.However,the microstructure of the Al-1%Si ingot is not suitalbe for the PVD process in semiconductor fabs due to its big grain size and uneven orientation.Target with fine and uniform grain size and orientation is need to have a uniform film depsotion on the silicon wafer.Thermal mechanical process need to be performed on the ingot material to have a small and uniform grain size.The parameters of the thermal mechanical process such as the deformation rate and heat treatment are important for the results of uniform grains.In this study,firstly,by the method of EBSD,the starting recrystallization temperature and the complete recrystallization temperature were studied,the static recrystallization kinetics was studied.It is found that for high purity Al-1%Si,with 85% deformation,the starting recrystallization temperature is 310?,the complete reccrystallizaton temperature is 370?.Static recrystallzation kinetics study at temperature 430? found that 85% deformation sample start to have recrystallization phenomena in 0.5 minute,in 2 minutes it was fully recrystallized.While for 75% deformation sample,the recrystallization starting point is much later at 2 minuites,in 3 minutes it was fully recrystallized.At same temperature,higher deformation rate,it shows earlier recrystallization phenomena.Secondly,the deisgn of experiment with metallographic technique was performed on the parameter deformation rate,heat treatment temperature and the heat treatment time.A optimized deformation rate is obtained in the experiment.The results of the design of experiments shows that both deformation rate,heat treatment temperature and time play a major role in recrystallization process.It is found that to obtain the fine and unform grain size,the optimized parameters are with deformation rate 80%-85%,heat treatment temperature at 390?-430?,heat treatment time is okay with ranges from 5 minutes to 60 munites but 15 minutes is the best.A finite element analysis of the heat treament was performed at temperature 410? to check whether there is any big temperature different between the target center and target edge.The simulation shows that the all area in the target reach the set temperature within 3 minutes,which indicate that the heat treatment will have similar results in different location of the target.Finally,a actual sized target was process with 85% deformation rate,410?,15 minutes.Resutls shows a uniform grains with range from 60?m to 80?m was obtained,which is fully matches the semicoductor PVD process requirement.The results of this study on the effect of thermal mechanical process on static recrystallization of high purity Al-1%Si material,is important and is the guidline for the actural target manufatoring.