Refinements to the miniature mixed mode bending (MMMB)
interface delamination setup
Citation for published version (APA):
Murthy Kolluri, N. V. V. R., Hoefnagels, J. P. M., Dommelen, van, J. A. W., & Geers, M. G. D. (2009). Refinements to the miniature mixed mode bending (MMMB) interface delamination setup. Poster session presented at Mate Poster Award 2009 : 14th Annual Poster Contest.
Document status and date: Published: 01/01/2009 Document Version:
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Mechanics of Materials
Refinements to the Miniature Mixed Mode
Bending (MMMB) Interface Delamination
Setup
M. Kolluri, J.P.M. Hoefnagels, J.A.W. van Dommelen, M.G.D. Geers
/department of mechanical engineering
Problem definition
High density integration of several components in a single mod-ule (e.g. System In Package (SIP), Fig. 1a) makes the interfaces between stacked layers of dissimilar materials vulnerable to de-lamination (Fig. 1b).
Fig. 1(a). Cross section of a typical SIP (b). Scanning acoustic image of a delaminated package. Red areas indicate delaminated regions.
Current MMMB setup
An MMMB setup capable of carrying out in-situ tests on minia-ture strucminia-tures for characterization of delamination was suc-cessfully developed and tested [Ref. 1]. Main advantages in-clude its ability to identify/measure: (i) precise crack length (Fig. 2 a – d), (ii) delamination mechanisms (Fig. 2e, 2f), and (iii) Critical Energy Release Rate over complete range of mode mixities (Fig. 2g, 2h).
Fig. 2Experimental results from the current setup illustrating its capa-bilities. Figures a – f are from in-situ SEM observation.
Why improvements?
To enhance its range of applicability by increasing its limits of (i) maximum load from 20N ⇒ 50N, (ii) maximum displacement, and to improve its ease-of-use by increasing its (iii) robustness.
Details of the improvements
Improvements in the design are made by geometry optimiza-tion of the main loading mechanism (MLM) and hinges. Impor-tant changes include (Fig. 3): (i) introduction of new hinges (1,2), (ii) replacement of the critical hinges with elliptical hinges to have more rotation (3), (iii) optimization of hinge geometry and increased robustness (4), (iv) all hinges are loaded in ten-sion (5), and (v) increased length of the MLM (6).
Fig. 3Design of the (a) current and (b) new improved setup. Improve-ments are highlighted and numbered. MMMB setup mounted in micro-tensile stage and eventually in SEM chamber is shown in (c).
Conclusion
MMMB device is a powerful tool for in-situ delamination test-ing. Design of the MMMB setup has been improved to increase its applicability and ease-of-use.
Valorization
Our industrial partners are positive to have a setup working at Philips for interface failure characterization of multi-layered SIPs.
Future work
Delamination characterization of lead frame - molding com-pound interface structures using improved MMMB device.
References:
