14.2
A Comprehensive FA Approach to Lifted Bond Balls Package Failure
A Comprehensive FA Approach to Lifted Bond Balls Package Failure
Thursday, November 7, 2013: 3:25 PM
Meeting Room 230B (San Jose McEnery Convention Center)
Summary:
Open pins as a result of lifted bond balls can be from numerous sources such as package delamination, mis-bonding, poor IMC formation, bond pad corrosion, etc. For lifted bond balls, a cross section is typically ordered to study the bonding interface. A more accurate and comprehensive method would be using a combination of C-SAM of the bond pads through bulk silicon, LASER inspection through bulk silicon, and mechanical separation of the interface layer. C-SAM through bulk silicon provides information on CMOS/encap delamination and information on all the bond pads, not just the tested open ones. LASER inspection through the bulk silicon provides information on the state of the silicon, such as cracking, under the bond balls. Lastly, the mechanically separate the delaminated interface allows the inspection of the bonding interface without induction of artifacts. A mechanical method was developed by gluing a metal block to the backside silicon and the front side of package, and then the mechanically pulling them apart, creating a perfect separation without twisting. The FA approach enables finding not only failure mechanism, but also root cause of failure. Actual FA cases will be presented
Open pins as a result of lifted bond balls can be from numerous sources such as package delamination, mis-bonding, poor IMC formation, bond pad corrosion, etc. For lifted bond balls, a cross section is typically ordered to study the bonding interface. A more accurate and comprehensive method would be using a combination of C-SAM of the bond pads through bulk silicon, LASER inspection through bulk silicon, and mechanical separation of the interface layer. C-SAM through bulk silicon provides information on CMOS/encap delamination and information on all the bond pads, not just the tested open ones. LASER inspection through the bulk silicon provides information on the state of the silicon, such as cracking, under the bond balls. Lastly, the mechanically separate the delaminated interface allows the inspection of the bonding interface without induction of artifacts. A mechanical method was developed by gluing a metal block to the backside silicon and the front side of package, and then the mechanically pulling them apart, creating a perfect separation without twisting. The FA approach enables finding not only failure mechanism, but also root cause of failure. Actual FA cases will be presented