Reliability at the Chip Interfaces: Delaminating the Silicon Die from Molding Compound

Reliability at the Chip Interfaces: Delaminating the Silicon Die from Molding Compound

Schlottig, G.

Ernst, L.J. (promotor)

Mechanical, Maritime and Materials Engineering

Precision and Microsystems Engineering

2012-11-30

This book describes a setup that allows to delaminate the Silicon-to-Molding Compound interface for obtaining interfacial fracture parameters: the Mixed Mode Chisel setup (MMC). With this device for the first time the delamination can be initiated and propagated, while preventing the occurrence of random brittle fracture in one or both of the adjacent materials. This is relevant because of the fact that material interface delamination in electronic components forms a major failure problem. The technology trend to densify components results into more and more interfaces with accompanying growing complexity where thermo-mechanical interactions play a crucial role. Rapidly being able to establish the interfacial properties is crucial for the quantitative design process. The present work answers questions on how to delaminate Siliconto-Molding Compound interfaces, how an adequate specimen can be shaped and fabricated, how random fracture can be overcome, what facts are influencing the delamination most, what impact the residual stresses and the viscoelasticity of EMC have, and how the fracture strength compares to that of other interfaces. It describes the setup details, the design choices, the relevant conditions for manufacturing and processing, the choices being made for compression molding and transfer molding and the formation of a starter crack. The delamination experimental procedure and the necessary steps to determine the interface properties are described in detail, including crack length measurements. The results obtained, including the reliability, are discussed. It also describes decisive aspects of interpreting, comparing and applying fracture mechanical results as well as their display. The MMC can be used at elevated temperature and moisture conditions and can be clamped to different loading devices. The Critical Energy Release Rate Gc was found ranging between 50 and 200 J/m2 for a Mode Mix range of 15° at room temperature. The practical Mode Mix values depend on a chosen reference length and a measure of the material mismatch as given in the text. The deviation from a polynomial fit of 2nd order reaches a maximum of 20 %. In the concluding chapter a multi-specimen approach for future delamination measurements and further research on mode mix and reference length choices are being advised.

delamination
fracture mechanics
electronic packaging
interfacial fracture toughness
molding compound
silicon
mixed mode
pre-crack

https://doi.org/10.4233/uuid:926bb24d-973f-4f1b-93da-4e6cde8fbbda

9789461860729

Institutional Repository

doctoral thesis

(c) 2012 Schlottig, G.