Failure Analysis for Qualification of Stiffener Attachment to Thin-core Substrates

Stiffener adhesion to thin-core substrates is essential to package warpage control. Through temperature cycling reliability tests, 5.25% of the packages was identified having stiffener “pop-up”. In this paper we demonstrate the usage of failure analysis techniques to identify weak stiffener adhesion as the underlying cause of open failures. The failure analysis work drove critical decision on qualifying stiffener vendors.