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Orlando Consuelo, Christopher Flores, Jonah Tan, Intel Technology Philippines, Inc.
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Die-level failure analysis (FA) is a challenge for chip-scale packages such as the micro-ball grid array (micro-BGA). Conventional FA of micro-BGA would require the removal of the die from the package and its rebonding to an interposer to allow front-side fault isolation. This technique poses a high risk for die damage, not to mention the large amount of time it requires. This study demonstrated the possibility of performing backside fault isolation on micro-BGA's through backside emission analysis. Backside fault isolation was shown to require proper die thinning, surface mounting, and the use of emission microscope with a near infrared radiation capacbility. Successful die thinning, which is a critical step of the procedure, can be accomplished by proper tuning of factors such as diamond grit size, polishing wheel speed, polishing head rotation speed, and oscillation. Surface mounting, on the other hand, requires proper alignment and reflow. Backside fault isolation using this technique was proven to be less time-consuming and poses a lower risk for inadvertent die damage.
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