Chun-yue Huang

Analysis of solder joint shape parameters on the stress and strain of the solder joint in the random vibration condition

In this paper, the finite element model of optical interconnection module is established, and the finite element analysis of the model is carried out under the condition of random vibration loading based on ANSYS software. The distribution law of the stress and strain of the solder joint array is obtained. As an example, the stress and strain of the solder joint array with single factor variation of the shape parameters of the model were analyzed under the random vibration condition. The results show that the distribution of the stress and strain of the solder joint array is not uniform, and the change tendency of the stress and strain is presented by the inner layer of the solder joint to the outer solder joint. Among them, the maximum stress strain value of solder joints in the corner of the outer layer of the solder joints array region. With the increase of height of solder joint, solder joint array should strain showed a tendency to increase, along with increase of the volume of solder joint, solder joint array should stress and strain values decrease gradually, with pad diameter increases, the solder joint array should stress and strain value increases.

The FEM analysis of stress and strain in stacked solder bump under power load

The PBGA (Plastic Ball Grid Array) stacked solder bump finite element analysis model was set up, the temperature field analysis and thermal-structural coupling analysis were carried out under power load based on the model. The effects of solder pad size and solder volume on thermal stress distributed in the solder ball were analyzed. The results illustrated that the distribution of temperature in the PBGA package structure is non-uniform. The chip has the highest temperature. At the far end of PCB diagonal, the temperature reaches the minimum. The maximum stress and the maximum equivalent plastic strain occur in the most distal corner solder ball. The contact area between upper solder ball and chip has the maximum stress and strain. With the variation solder pad size, the thermal stress in the solder ball changes corresponding. With variation of the solder volume, the equivalent stress in the ball changes corresponding. The equivalent stress decreases with solder volume increased.

Research of via about signal integrity facing complete transmission path

The HFSS electromagnetic simulation model of a complete transmission path structure was established, analyzed the signal integrity of complete transmission path in high frequency and acquired the return loss of complete transmission path based on the model. The effect of external diameter of via, inner diameter of via and height of via to signal integrity of complete transmission path were studied. And external diameter of via, inner diameter of via and height of via as design parameter, the parameters of different levels in the 9 groups combined return loss of complete transmission path with different via were analyzed by analysis of variance using orthogonal design method. The results show that with the height of via, external diameter of via and inner diameter of via increases, the return loss of complete transmission path also increases; when the confidence is 95%, the influence of height of via and external diameter of via to signal integrity of complete transmission path is highly significant, and the effect of inner diameter of via to signal integrity of complete transmission path is not significant.

Finite element analysis of micro-scale CSP solder joint in 3D packaging under random vibration

In this study three-dimensional finite analysis models of 3D micro-scale chip scale package (CSP) solder joints were set up. The stress-strain distribution of micro-scale CSP solder joints was obtained by finite element analysis under the condition of random vibration load. The influence of different solder, pad diameter and solder joint volume on the stress-strain of micro-scale CSP solder joint was analyzed. The results show that the maximum equivalent stress of SAC387 is the largest in SAC305, SAC387, 63Sn37Pb and 62Sn36Pb2Ag four kinds of solder joint materials under random vibration condition. When the maximum diameter of the joint is reduced from 0.105mm to 0.085mm, the stress and strain in the micro-scale CSP solder joint show an increasing trend. When the diameter of the pad is reduced from 0.09mm to 0.06mm, the stress and strain in the micro-scale solder joint show an increasing trend.

The stress strain analysis under the reverse load of the embedded baseplate micro-scale grid array welder

Established embedded substrate microscale ball grid array solder three point bending stress and strain finite element analysis model, analyzed the solder joint materials, spot diameter and the influence of the bending stress and strain of solder pad diameter, the results show that the torque load, the embedded type substrate microscale BGA solder joint array of maximum stress and strain are occurred to the periphery on the solder joint around the corner, and the maximum stress and strain in contact with the PCB side of the edge. When applying the same under torsion load: in SAC305, SAC387, 63 sn37pb, 62 sn36pb2ag four solder materials, adopting SAC387 solder joint maximum equivalent stress is the largest, 62 minimum bending stress sn36pb2ag material welds; When the diameter of the solder was reduced from 105 mu m to 80 mu m, the internal stress strain of the microscale CSP solder was decreased. When the diameter of the disc was reduced from 80 mu m to 60 mu m, the internal stress strain of the micro-scale welder was increased.

Study of Package-on-Package solder joints under random vibration load based on Patran

The 3D finite element analysis model of Package-on-Package solder joints was set up based on Patran software. The natural frequency, vibration mode of the model was analyzed under the condition of random vibration, the stress and strain distribution and the strain power spectrum density of response curves of the Package-on-Package solder joints were obtained, and the random vibration fatigue life of the Package-on-Package solder joints were also calculated out based on the power spectrum and rain flow count method; the influence of pad diameter on the random vibration fatigue life of the Package-on-Package solder joints were analyzed. The results show that the Package-on-Package solder joints of the model in this paper has the random vibration fatigue life of 997 hours; on the condition of the pad diameter of the second-layer solder joints increases from 0.15 mm to 0.30mm, the Package-on-Package solder joints vibration fatigue life increases with the increase of the pad diameter.

Effects of shape parameters on tensile strength of Cu bump

Three parameters, Copper pad material, Pad thickness, and Bump Patterns were chosen as three control factors. By using an L9(34)orthogonal array the copper stud bump solder joints which have 9 different combinations of parameters were designed. The finite element analysis models of 9 copper stud bump solder joints were established by using ANSYS/LS-DYNA, and analyzed the finite element tensile simulation. Tensile strain data of copper stud bump solder joint were obtained under 9 different parameters combinations; it was analyzed through range analysis and variance analysis. The result shows that of the three parameters, the descending order of affecting the copper stud bump solder joint tensile strain is Copper pad material, Bump Patterns, and Pad thickness. With 95% confidence, Copper pad material has a significant effect on the copper stud bump solder joint tensile strain whereas bump patterns and pad thickness has little.