Research On Crack Propagation Behavior Of Chip With Pre-placed Stress

Chip self-destructive technology refers to integrated circuits or electronic devices performing self-destruction or destroying main circuit function in a timely manner when receiving specific signals.Self-destruction technology has a wide range of applications in information security,medical health,military intelligence applications,etc.However,these self-destructive schemes are simple in structure and single in function,which is impossible to realize self-destruction on the basis of complex functions of silicon substrate chip.Most of the procedure of self-destruction triggering and destruction is based on the experimental perspective;few articles are based on the physical failure theory for finite element analysis and simulation to study the influencing factors affecting the whole self-destruction process.This paper shows a thermally triggered silicon-based transient electronic chip with pre-placed thermally expandable microspheres.Based on the cohesive fracture theory of extended finite elements,a set of(electric)thermal-stress-fracture simulation model is established.The fracture behavior of silicon-based transient electronic chip under thermal load is simulated by using the finite element software ABAQUS.For the factors affecting the crack expansion of silicon wafers,ABAQUS software is used to simulate the propagation behaviors of different types of cracks in silicon wafers,and investigated the effect of hole stress concentration on the crack tip stress intensity factor(SIF)and crack propagation behavior.For the introduction scheme of the pre-placed stress,it was researched in two aspects.On the one hand,thermal expansion properties of micro-colloids of different volumes were studied experimentally,as well as the influence of mixing ratio and bubbles on the properties of micro-colloids.the fabrication method of micro-colloids was formulated,and the experimental method of pre-placed stress chip was designed.On the other hand,based on the principle of stress concentration,the same volume etching schemes were designed,such as single pattern,array distribution and strip pattern.The distribution of stress field after filling expansive material was simulated by ABAQUS software.The simulation results show that the extreme stress and maximum principal stress values of square etching graphics are the best in the graphical etching scheme.In order to solve the difficult problem of multi-physics field crack simulation,the(electric)thermal-stress-fracture simulation model is proposed based on the cohesive damage and fracture theory of the extended finite element of thermally triggered siliconbased transient electronic chip.The fracture simulation model is embedded with ABAQUS multi-physical field sequential coupling method,which realizes the multiphysical field crack simulation function.In the thermal-force-fracture simulation,the temperature of the micro-colloids rises to 122? within 3.4s.The results show that the cracks occur in the stress concentration area near the contact surface between the microcolloids and the silicon wafer,and eventually expand to form the annular failure.The simulation results are in good agreement with the experimental results.The simulation results are basically in agreement with the experimental results,and the accuracy of the calculation is verified by the energy viewpoint.Based on thermal triggering requirements of pre-placed stress chips,a thermal trigger scheme based on resistance wire circuit is proposed,and the methods of adding the edge crack is used to solve the problem of incomplete expansion of the chip boundary.In the electrical-thermal-force-fracture simulation,the relationship between the electrical conductivity of the resistive wire material and the optimum expansion temperature reached by the micro-colloids was studied.The simulation results show that the cracks begin to propagate from the preset crack,and two cracks appear at the edge of the chip.The fracture experiments by adding the edge cracks show that the chip boundary has been fractured,which shows that the crack simulation is well guided for the experiments.