Underfill delamination and lead-free solder extrusion on an encapsulated chip capacitor during high-temperature life testing
Underfill delamination and lead-free solder extrusion on an encapsulated chip capacitor during high-temperature life testing
Thursday, November 4, 2021: 8:50 AM
104 ABC (Phoenix Convention Center)
Summary:
With the legislative health restrictions on lead which was previously used in tin-lead solders, COTS parts have transitioned to pure-tin finishes and lead-free solders, such as Sn-Ag-Cu (SAC). For COTS part usage space applications, techniques such as coating over solder terminations or surrounding parts with underfill are often used to avoid the threat of tin-whisker shorting; however, proper care must be taken to ensure that these preventative measures are not introducing their own, new failure mechanisms. The work detailed here, a latent failure in an encapsulated and underfilled COTS chip capacitor, was heavily related to the usage of SAC305 and underfill on the capacitor, with implications for both the solder and encapsulation materials used with parts of this type.
With the legislative health restrictions on lead which was previously used in tin-lead solders, COTS parts have transitioned to pure-tin finishes and lead-free solders, such as Sn-Ag-Cu (SAC). For COTS part usage space applications, techniques such as coating over solder terminations or surrounding parts with underfill are often used to avoid the threat of tin-whisker shorting; however, proper care must be taken to ensure that these preventative measures are not introducing their own, new failure mechanisms. The work detailed here, a latent failure in an encapsulated and underfilled COTS chip capacitor, was heavily related to the usage of SAC305 and underfill on the capacitor, with implications for both the solder and encapsulation materials used with parts of this type.