Stress Simulation And Optimization Of IC Based On CDFN Package

With the development of miniaturization of integrated circuits,the requirements for packaging technology are becoming higher and higher,and various packaging technologies came into being.Due to the difference of thermal expansion coefficient and thermal conductivity of packaging materials,temperature change will produce thermal stress among materials,and failure will occur among materials with weak stress resistance.In addition,mechanical stress is also one of the factors for packaging failure.In this thesis,a double flat packaging structure is modeled.Through the finite element analysis method of ANSYS software,the thermal stress is simulated in the thermal structure coupling,and the results of two kinds of conductive adhesive and two kinds of plastic packaging materials are compared.At the same time,the model thermal stress of three kinds of adhesive thickness is compared and analyzed.Finally,the reliability of the packaging product of the company is improved through reliability experiment and C-Scan analysis;In the steady-state structure module,the mechanical stress of each model under fixed external force and random vibration is simulated.In the analysis of thermal stress model,apply temperature load to the model and observe the stress distribution inside and outside the model.The results show that due to the parameters such as thermal expansion coefficient and Young's modulus,when 15?m EPOXY-2 is matched with EMC-2,the package performs well in terms of thermal stress,and the maximum thermal stress is 689.82 MPa.In its thermal stress nephogram,the thermal stress at the package pin and connecting bar is relatively large.At the same time,due to the small thermal mismatch between the chip and adhesive and the plastic packaging material,the thermal stress is also small.In the stress analysis of the fixed external force model,the support point is established at the bottom of the pin,the external force of 10 units is applied at the center of the top of the package,and the mechanical stress nephogram of each model is observed.Due to the different Young's modulus of the material,the maximum mechanical stress of the model with EMC-2 is roughly twice than that of EMC-1.In terms of deformation,the deformation difference of the model with the same plastic packaging material is small.The average deformation of the model with EMC-2 is 0.09% of the package thickness,while that with EMC-1 is 0.01%.Under the condition of random vibration,the mechanical stress of the model using EMC-2 is lower than that using EMC-1.The former range is 0.1-0.13 MPa and the latter range is 0.2-0.48 MPa.At the same time,the performance of EPOXY-2 is slightly better than that of EPOXY-1.In terms of experimental verification,the temperature cycle test and C-SAM analysis of the above packages were carried out.It was found that when 15 um EPOXY-2 and EMC-2 were combined,the number of layered samples was small,the yield was 93.33%,and the ratio of the total layered area to the single package area was 5.59%.Compared with 76.67% of the corresponding samples before optimization,the yield increased by16.67%,and the total delamination area decreased by 13.96%.In terms of mechanical stress test,because there is no effective way or equipment to measure its size,only simulation analysis is carried out.