Nowadays, electronic packages have been widely applied in many fields. Higher and higher requirement in thermal and mechanical reliabilities are plaguing a lot of researchers and engineers. For the reliability concern, various test methods have been put up, such as the temperature cycling test, drop test, bend test, electromigration test and high temperature storage (HTS) test etc. On the other hand, conducting experiments may cost lots of money and time, so finite element analysis (FEA) simulation study is playing a very important role in this field.

The Small Outline Transistor (SOT) package shows failure in die attach connection under HTS test. The failure mode is that die attach connection in SOT package was damaged so that the package lost the electrical connection. To solve s...[ Read more ]

Nowadays, electronic packages have been widely applied in many fields. Higher and higher requirement in thermal and mechanical reliabilities are plaguing a lot of researchers and engineers. For the reliability concern, various test methods have been put up, such as the temperature cycling test, drop test, bend test, electromigration test and high temperature storage (HTS) test etc. On the other hand, conducting experiments may cost lots of money and time, so finite element analysis (FEA) simulation study is playing a very important role in this field.

The Small Outline Transistor (SOT) package shows failure in die attach connection under HTS test. The failure mode is that die attach connection in SOT package was damaged so that the package lost the electrical connection. To solve such a problem, we conducted our analysis considering four factors: HTS test condition, material, structure design and pre-crack. Different factors shows various influence on strain level in die attach surface during HTS test. Finally it shows that with same test condition, material and structure design, SOT package with pre-crack has much higher strain level than that without pre-crack.

To clearly understand different effects on strain level in die attach surface of delaminated SOT package, the parameter sensitivity analysis technique has been applied. The influence of each variable and most significant factors were presented. Then we combined simulation and experiment results and put up a novel failure criterion based on the maximum shear strain in die attach surface. For further consideration, the response surface methodology (RSM) was served for design optimization.