Stacked Microscale Wafer Temperature Field And Stress Field Distribution In The Laser Spike Annealing Process

With the logical node size of the complementary metal oxide semiconductor components continue to miniaturization,and requirements for rapid thermal annealing process are increasingly demanding.The "patter effect" caused by the surface pattern in the laser spike annealing process of wafer,will result in nonuniform temperature distribution in the wafer,excess thermal stress and crystal defects,which led to transistor electrical performance variation,so it becomes one of the problems that need to be solved in the process of making semiconductor components.Based on this,the paper carried a simulation on five stacked microscale wafer in a carbon dioxide laser spike annealing temperature distribution to provide theoretical support for elininating the "pattern effect".In this paper,based on the thermal conduction equation,the finite element simulation software COMSOL was used to simulate the microstructures of stacked microscale wafers under continuous carbon dioxide laser irradiation.The temperature field distribution of stacked microscale wafers was obtained.Then,introduced(elastic modulus,poisson's ratio and coefficient of thermal expansion)of silicon,polysilicon,silicon dioxide and silicon nitride.The calculated temperature was applied as load to the mechanical model of stacked microscale wafer.stress field distribution of stack microscale wafer during laser spike annealing process.The main conclusions are as follows:(1)The effects of laser power and heating time on temperature distribution of the stacked microscale wafer.When the laser power is fixed,The surface spike temperature of stack 2(silicon/polysilicon)and stack 5(silicon/polysilicon/silicon nitride)increases linearly with heating time,The surface spike temperature of stack 3(silicon/polysilicon/silicon dioxide)and stack 4(silicon/polysilicon/silicon dioxide/silicon nitride)increases in the form of ladder-type with heating time;In the depth direction,the diffusion distance of the microstrip wafer increases with the increase of the heating time,In the depth direction,the diffusion distance of the isothermal line increases with the increase of the laser power,while the temperature of the stack microscale wafer surface increases linearly with the laser power.At the same time fixed heating time and laser power,stack layer surface temperature gradually reduced,amplitude is not great.(2)The effects of laser power and heating time on stress distribution of the stacked microscale wafer.For the fixed heating time,the von mises stress in the depth direction of the stack microscale wafer increases with the laser power.The von mises stress on the left end of the microscale wafer at different stack microscale depths is larger than the von mises stress of the right end at 400?s,,600ps and 800?s.When the laser heating time is 1000?s,the right end The von mises stress is greatest.The von mises stress of different stack surfaces decreases first and then increases with the increase of heating time.The maximum stress occurs at the edge of the polysilicon,the most dangerous part of the stacked microscale wafer or prone to spall at the polysilicon surface.