Research On Yield Improvement Of FRD Based On Epitaxial Process

Silicon epitaxial wafer material is the basic special functional material of modern large-scale integrated circuit silicon device.Silicon material is the foundation and pillar material of electronic information industry.Among them,silicon epitaxy plays an important role in semiconductor devices,and the quality of the epitaxial layer has an important impact on the final electrical parameters of the product.This paper focuses on how to optimize the epitaxial process and how to match the equipment spare parts.To reduce the slip line defects in the silicon epitaxial layer,and use the fast recovery diode as the research carrier,the degree of influence of each factor is quantified by the product yield.The experimental data proves that when the deformation degree of the silicon wafer can be more closely matched with the spherical groove base,the more uniform the heat is,the lower the temperature gradient in the silicon wafer is,the smaller the thermal stress is,the slip line defects are reduced,and the yield is improved.For the temperature rise and fall time adjustment in the process program,the extension of the heating time time can alleviate the accumulation of thermal stress,which is more conducive to the uniform distribution of temperature in the silicon wafer and the defect area is reduced.By adjusting the coil height to compensate the influence of the airflow on the temperature,the defect can be effectively reduced,and the coil height is also one of the influencing factors affecting the slip line defect.In the case where the above factors are changed together,the back edge of the substrate is removed.For the FRD product process,a uniform resistivity distribution and a product yield of 95% or more are obtained when the width of the edge is 0.6 mm.