Here is the abstract you requested from the DPC_2009_FlipChip technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Assessment of Impact of Alpha Emissivity of Packaging Materials on the Soft Error Rate of Flip Chip Devices|
|Keywords: low alpha, soft error, flip chip|
|Soft error failures due to ionizing radiation remain to be a lingering reliability concern for semiconductor devices. Among the contributing factors of soft errors, alpha particle emission from packaging materials is one of the most important because of these materials’ immediate contact or close proximity to the sensitive area of silicon devices. Specifically for flip chip packages, alpha emission rates of materials such as solder bump and underfill have been controlled by most component manufacturers, however the allowance for maximum emissivity levels vary from manufacturer to manufacturer. For ASIC design, since on-chip error detection and correction cannot cover 100% of chip due to various reasons, soft error failures due to high alpha-emission package materials still occur in the field for some of the critically important electronic systems. In this work, we will present a series of alpha particle induced soft error failures and the analytical results collected on these devices. Locations of the soft errors on the silicon are mapped and their relative locations to the packaging material components will be discussed. Results from the failure analysis including cross-section, SEM, and EDX results will be presented. The results will demonstrated that due to the shrinking bump pitch and bump sizes, some of the materials that were not previously considered critical in terms of alpha particle emission, such as pre-solder on the substrate, will in fact need to have strictly controlled alpha emission levels. For currently acceptable FIT levels, guidelines for the maximum allowed alpha emission rates will be provided for the key packaging materials in flip chip devices.|
Cisco Systems, Inc.
San Jose, CA