Studies on the reliability of power packages based on strength and fracture criteria

Modelling of Reliability by Highly Accelerated Characterization Method for Solid State Lighting LED Boards

“…Relatively small number of thermal cycles (in order of thousands) can lead to rapid failure especially in solder joints [7]. The discrepancy of thermal expansions coefficients of LED package materials and LED board materials can cause very high mechanical stresses especially in small solder joints that connect LED package with PCB board.…”

Determination of adhesion and delamination prediction for semiconductor packages by using Grey Scale Correlation and Cohesive Zone Modelling

“…The adhesion of material combinations can be measured by Button-Shear-Test (BST) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] . Fig.…”

“…Fig. 16 shows the strategy to built-up a FEM model with cohesive zone elements in a semiconductor package at the interfaces which have to be investigated [18][19][20].…”

“…17a-c show the delamination prediction by using CZM on the example of a TO220 package and the comparison to experimental results after temperature cycling (À65/150°C, 500Â, ultrasonic scan) (done by ABAQUS). For the simulations a minimum fracture energy of E PreCrack = 10 J/m 2 was used (visco-elastic simulation for moulding compound, solder as die attach with creep model) [18][19][20]. In the CZM a ratio of 5:1 between shear and traction mode was fixed.…”

“…In the CZM a ratio of 5:1 between shear and traction mode was fixed. A cooling-down step from 165°C to À65°C was applied as load (chemical shrinkage of moulding compound was not considered) [18][19][20]. Simulation with CZM approach and experimental results after temperature cycling show same kind of delamination on the die pad near the chip edges for TO220 package.…”