Analysis of Interface Cracking in Flip Chip Packages With Viscoplastic Solder Deformation

2003 ◽  
Author(s):  
M. J. Heffes ◽  
H. F. Nied
Keyword(s):  
Flip Chip ◽  
Strain Energy Release ◽  
Solder Material ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Interfacial Cracks ◽  
Fracture Parameters ◽  
Solder Bumps ◽  
Interface Cracking ◽  
Semiconductor Packages

This paper examines the modeling of viscoplastic solder behavior in the vicinity of interfacial cracking for flip chip semiconductor packages. Of particular interest is the relationship between viscoplastic deformation in the solder bumps and any possible interface cracking between the epoxy underfill layer and the silicon die. A 3-D finite element code, developed specifically for the study of interfacial fracture problems, was modified to study how viscoplastic solder material properties would affect fracture parameters such as strain energy release rate and phase angle for nearby interfacial cracks. Simplified two-layer periodic symmetry models were developed to investigate these interactions. Comparison of flip chip results using different solder material models showed that viscoplastic models yielded lower stress and fracture parameters than time independent elastic-plastic simulations. It was also found that adding second level attachment greatly increases the magnitude of the solder strain and fracture parameters. As expected, the viscoplastic and temperature dependent elastic-plastic results exhibited greater similarity to each other than results based solely on linear elastic properties.

Analysis of Interfacial Cracking in Flip Chip Packages With Viscoplastic Solder Deformation

2004 ◽  
Vol 126 (1) ◽  
pp. 135-141 ◽  
Author(s):  
M. J. Heffes ◽  
H. F. Nied
Keyword(s):  
Flip Chip ◽  
Strain Energy Release ◽  
Solder Material ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Interfacial Cracks ◽  
Fracture Parameters ◽  
Solder Bumps ◽  
Interface Cracking ◽  
Semiconductor Packages

This paper examines the modeling of viscoplastic solder behavior in the vicinity of interfacial cracking for flip chip semiconductor packages. Of particular interest is the relationship between viscoplastic deformation in the solder bumps and any possible interface cracking between the epoxy underfill layer and the silicon die. A 3-D finite element code, developed specifically for the study of interfacial fracture problems, was modified to study how viscoplastic solder material properties would affect fracture parameters such as strain energy release rate and phase angle for nearby interfacial cracks. Simplified two-layer periodic symmetry models were developed to investigate these interactions. Comparison of flip chip results using different solder material models showed that viscoplastic models yielded lower stress and fracture parameters than time independent elastic-plastic simulations. It was also found that adding second level attachment greatly increases the magnitude of the solder strain and fracture parameters. As expected, the viscoplastic and temperature dependent elastic-plastic results exhibited greater similarity to each other than results based solely on linear elastic properties.

scholarly journals Mechanics Of Interfacial Crack Propagation In Microscratching

1996 ◽  
Vol 436 ◽  
Author(s):  
Maarten P. de Boer ◽  
John C. Nelson ◽  
William W. Gerberich
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Grain Boundary ◽  
Interfacial Crack ◽  
Strain Energy Release ◽  
Linear Elastic ◽  
Interfacial Cracks ◽  
Bending Strain ◽  
Diamond Indenter ◽  
Boundary Fracture

AbstractA new probing technique has been developed to test thin film mechanical properties. In the Microwedge Scratch Test (MWST), a wedge shaped diamond indenter tip is drawn along a fine line, while simultaneously being driven into the line. We compare microwedge scratching of Zone 1 and Zone T thin film specimens of sputtered W on SiO2. Symptomatic of its poor mechanical properties, the Zone 1 film displays three separate crack systems. Because of its superior grain boundary strength, the Zone T film displayed only one of these - an interfacial crack system. Using bimaterial linear elastic fracture mechanics, governing equations are developed for propagating interfacial cracks, including expressions for strain energy release rate, bending strain, and mode mixity. Grain boundary fracture strength information may be deduced from the Zone 1 films, while adhesion may be inferred from the Zone T films.

The Use of Precision Selective Area Milling for Failure Analysis of Flip-Chip Packages

2002 ◽  
Author(s):  
George F. Gaut
Keyword(s):  
Failure Analysis ◽  
Flip Chip ◽  
Solder Bump ◽  
Selective Area ◽  
Fill Material ◽  
Solder Bumps ◽  
Time Required

Abstract Access to the solder bump and under-fill material of flip-chip devices has presented a new problem for failure analysts. The under-fill and solder bumps have also added a new source for failure causes. A new tool has become available that can reduce the time required to analyze this area of a flip-chip package. By using precision selective area milling it is possible to remove material (die or PCB) that will allow other tools to expose the source of the failure.

scholarly journals Demonstration of fine pitch FCOB (Flip Chip on Board) assembly based on solder bumps at Fermilab

2009 ◽  
Vol 4 (11) ◽  
pp. T11001-T11001
Author(s):  
E Skup ◽  
M Trimpl ◽  
R Yarema ◽  
J C Yun
Keyword(s):  
Flip Chip ◽  
Fine Pitch ◽  
Solder Bumps

Defect Detection of Flip Chip Solder Bumps Through Local Temporal Coherence Analysis of Laser Ultrasound Signals

2007 ◽  
Author(s):  
Jin Yang ◽  
Charles Ume
Keyword(s):  
Defect Detection ◽  
Flip Chip ◽  
Solder Bump ◽  
Temporal Coherence ◽  
Coherence Analysis ◽  
Laser Ultrasound ◽  
Surface Mount ◽  
Flip Chips ◽  
Solder Bumps ◽  
Ultrasound Signals

Microelectronics packaging technology has evolved from through-hole and bulk configuration to surface-mount and small-profile ones. In surface mount packaging, such as flip chips, chip scale packages (CSP), and ball grid arrays (BGA), chips/packages are attached to the substrates or printed wiring boards (PWB) using solder bump interconnections. Solder bumps, which are hidden between the device and the substrate/board, are no longer visible for inspection. A novel solder bump inspection system has been developed using laser ultrasound and interferometric techniques. This system has been successfully applied to detect solder bump defects including missing, misaligned, open, and cracked solder bumps in flip chips, and chip scale packages. This system uses a pulsed Nd:YAG laser to induce ultrasound in the thermoelastic regime and the transient out-of-plane displacement response on the device surface is measured using the interferometric technique. In this paper, local temporal coherence (LTC) analysis of laser ultrasound signals is presented and compared to previous signal processing methods, including Error Ratio and Correlation Coefficient. The results show that local temporal coherence analysis increases measurement sensitivity for inspecting solder bumps in packaged electronic devices. Laser ultrasound inspection results are also compared with X-ray and C-mode Scanning Acoustic Microscopy (CSAM) results. In particular, this paper discusses defect detection for a 6.35mm×6.35mm×0.6mm PB18 flip chip and a flip chip (SiMAF) with 24 lead-free solder bumps. These two flip chip specimens are both non-underfilled.

Load Regime Diagram of a Pipe With Cyclically Plastic Bending

2002 ◽  
Author(s):  
Yanping Yao ◽  
Ming-Wan Lu
Keyword(s):  
Axial Force ◽  
Bending Moment ◽  
Boundary Curve ◽  
Plastic Behavior ◽  
Cyclic Bending ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Load Regime ◽  
Reversed Cyclic ◽  
Cyclic Bending Moment

The criteria of piping seismic design based on linear elastic analysis has been proved to be conservative, which is mainly because the influence of plastic deformation on piping dynamic response is neglected. In the present paper, a pipe under seismic excitation is simplified as an beam with tubular cross section subjected to steady axial force and fully reversed cyclic bending moment, and the elastic-plastic behavior of the pipe is studied. Various behavior of the pipe under different combinations of axial force and cyclic bending moment is discussed and the boundary curve equations between them are obtained. Also the load regime diagram for a pipe which is formed by the boundary curve equations in the loading plane is given, from which the elastic-plastic behavior of the pipe can be determined directly.

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