Abstract Acoustic Micro Imaging (AMI) is an established nondestructive technique for evaluation of electronic packages. Non-destructive evaluation of electronic packages is often a critical first step in the Failure Analysis (FA) process of semiconductor devices [1]. The molding compound to die surface interface of the Plastic Ball Grid Array (PBGA) and Plastic Quad Flat Pack (PQFP) packages is an important interface to acquire for the FA process. Occasionally, with these packages, the standard acoustic microscopy technique fails to identify defects at the molding compound to die surface interface. The hard to identify defects are found at the edge of the die next to the bond pads or under the bonds wires. This paper will present a technique, Backside Acoustic Micro Imaging (BAMI) analysis, which can better resolve the molding compound to die surface interface at the die edge by sending the acoustic signal through the backside of the PBGA and PQFP packages.

Abstract This paper describes a method to "non-destructively" inspect the bump side of an assembled flip-chip test die. The method is used in conjunction with a simple metal-connecting "modified daisy chain" die and makes use of the fact that polished silicon is transparent to infra-red (IR) light. The paper describes the technique, scope of detection and examples of failure mechanisms successfully identified. It includes an example of a shorting anomaly that was not detectable with the state of the art X-ray equipment, but was detected by an IR emission microscope. The anomalies, in many cases, have shown to be the cause of failure. Once this has been accomplished, then a reasonable deprocessing plan can be instituted to proceed with the failure analysis.

Abstract Decapsulating wire-bonded plastic packages using fuming nitric or sulfuric acid is one of the most widely used methods for exposing a die during failure analysis [1]. The need to have physical access to the die in a packaged semiconductor device is often essential in the FA process. Regularly, the entire surface of the die must be exposed to take full advantage of techniques such as Emission Microscopy or Liquid Crystal. However, removing the plastic encapsulant using corrosive acids, such as fuming sulfuric acid, presents a challenge: achieving a fully exposed die surface while maintaining the device’s electrical functionality. Here we describe how our decapsulation process has evolved to address this challenge, resulting in improved survival rates for plastic packages decapsulated in the lab.