A study of new flip chip packaging process for diversified bump and land combination

Flip chip packages using plastic substrate is getting popular in IC packaging market. However, it still has not been standardized as real mass production system We have newly developed a flip chip packaging technology using nonconductive underfill resin sheet. The process now of the new flip chip packaging is as follows. First, underfill sheet is laminated onto substrate. Next, bumped die is aligned and attached onto substrate which is covered with underfill sheet under proper heat and pressure condition. The bumps under the die penetrate with displacing resin and eventually reaches to the metal land of the substrate. Finally curing the underfill sheet and metal connection are done. We have studied the possibility to apply this packaging technology to diversified bump and land combination with changing underfill component and process parameters. The electrical stability under several stress test conditions such as JEDEC Level-3 and TST has evaluated in this study. After the above evaluation, we have found that the packages which have been built in proper resin components and process parameters show good performance for all of these reliability tests almost regardless of bump and land materials.