A reliable failure analysis methodology in analyzing the elusive gate-open failures

Gate-open failures are typically caused by physical disconnections within the various gate contact interfaces inside the package such as gate lead post to wire bond, die bond pad to wire bond, or within the gate wire itself. Various challenges surround the analysis of gate-open failures. Among others are the electrical difficulty, the intermittent nature of the failure, electrical overstress clouding the gate-open failure mechanism, and uncertainties on the destructive chemical decapsulation process, which is sometimes doubted as a defect contributor. This makes the failure elusive and misleading, at times resulting to erroneous analysis. This paper aims to present a reliable failure analysis methodology in analyzing the elusive gate-open failures. An approach consisting of specially designed series of previously established failure analysis techniques and used in conjunction with a gate-open curve trace testing method by Palermo and Moreno. Actual case studies utilizing the mentioned approach are used to demonstrate the application of the methodology.