Thermo-Mechanical Reliability of Ag Porous Sheet Bonding Structures

In the present study, it was carried out to investigate the thermomechanical reliability in which harsh aging conditions on the commercial Ag nano-porous sheet bonding onto the die and substrate of both Ag plating surface finishes. To conduct thermo-mechanical reliability tests, die-attached specimens were placed in an oven operated at 250°C. Die-attached specimens were extracted at intervals of 125 h, 250 h, and 500 h to evaluate the shear strength of the Ag nano-porous sheet joints. All joints of Ag sheet bonded die-attachments that underwent thermal aging tests for up to 500 h maintained their robustness when combined with the Ag plating layer. The initial strength was about 43 MPa at the joining process temperature of 175°C, which caused an improvement in bonding strength more than two times that of 145 °C. Specimens bonded at 145°C, subjected to aging up to 250 h, exhibited an initial shear strength of approximately 20 MPa, which subsequently increased to about 45 MPa. However, beyond the 500h mark, the strength exhibited a decline, reverting to levels comparable to the initial approximately 20 MPa. In contrast, specimens bonded at 175°C exhibited an initial strength of approximately 42 MPa. Following the 250 h aging time, the strength increased to around 60 MPa. However, after 500 h, a notable decline in strength occurred, diminishing to 19 MPa, more than a twofold reduction from the initial strength.