Acoustic Microscope Inspection of Cylindrical Butt Laser Welds

Abstract Package delaminations are often associated with electrical and package reliability problems in IC devices. Delaminations caused by electrical-over-stress (EOS) and moisture expansion during reflow soldering have shown different delamination patterns. A Scanning Acoustic Microscope (SAM) can be used to detect package delaminations. Understanding these delamination signatures can help us quickly identify the failure cause at an early stage of the failure analysis.

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Failure Analysis of Flip-Chip Interconnections Through Acoustic Microscopy

ISTFA 1996: Conference Proceedings from the 22nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa1996p0277 ◽

1996 ◽

Author(s):

O. Diaz de Leon ◽

M. Nassirian ◽

C. Todd ◽

R. Chowdhury

Keyword(s):

Failure Analysis ◽

Large Scale ◽

Flip Chip ◽

Ultrasonic Waves ◽

Acoustic Microscopy ◽

Acoustic Microscope ◽

Chip Technology ◽

Ball Joints ◽

Non Destructive ◽

Scanning Acoustic Microscope

Abstract Integration of circuits on semiconductor devices with resulting increase in pin counts is driving the need for improvements in packaging for functionality and reliability. One solution to this demand is the Flip- Chip concept in Ultra Large Scale Integration (ULSI) applications [1]. The flip-chip technology is based on the direct attach principle of die to substrate interconnection.. The absence of bondwires clearly enables packages to become more slim and compact, and also provides higher pin counts and higher-speeds [2]. However, due to its construction, with inherent hidden structures the Flip-Chip technology presents a challenge for non-destructive Failure Analysis (F/A). The scanning acoustic microscope (SAM) has recently emerged as a valuable evaluation tool for this purpose [3]. C-mode scanning acoustic microscope (C-SAM), has the ability to demonstrate non-destructive package analysis while imaging the internal features of this package. Ultrasonic waves are very sensitive, particularly when they encounter density variations at surfaces, e.g. variations such as voids or delaminations similar to air gaps. These two anomalies are common to flip-chips. The primary issue with this package technology is the non-uniformity of the die attach through solder ball joints and epoxy underfill. The ball joints also present defects as open contacts, voids or cracks. In our acoustic microscopy study packages with known defects are considered. It includes C-SCAN analysis giving top views at a particular package interface and a B-SCAN analysis that provides cross-sectional views at a desired point of interest. The cross-section analysis capability gives confidence to the failure analyst in obtaining information from a failing area without physically sectioning the sample and destroying its electrical integrity. Our results presented here prove that appropriate selection of acoustic scanning modes and frequency parameters leads to good reliable correlation between the physical defects in the devices and the information given by the acoustic microscope.

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Stacked Die Analysis Using C-mode Scanning Acoustic Microscope

ISTFA 2005: Conference Proceedings from the 31st International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2005p0189 ◽

2005 ◽

Author(s):

Li Na ◽

Jawed Khan ◽

Lonnie Adams

Keyword(s):

Data Acquisition ◽

Image Interpretation ◽

Acoustic Microscopy ◽

Scanning Acoustic Microscopy ◽

Acoustic Microscope ◽

Analysis Mode ◽

Scanning Acoustic Microscope

Abstract For stacked die package delamination inspection using C-mode acoustic microscope, traditional interface and thorough scan techniques cannot give enough of information when the delamination occurs in multi-interfaces, and echoes from adjacent interfaces are not sufficiently separated from each other. A thinner thickness in the stacked-die package could complicate C-mode scanning acoustic microscopy (CSAM) analysis and sometimes may lead to false interpretations. The first objective of this paper is to briefly explain the CSAM mechanism. Based on that, some of the drawbacks of current settings in detecting the delamination for stacked-die packages are presented. The last objective is to introduce quantitative B-scan analysis mode (Q-BAM) and Zip-Slice technologies in order to better understand and improve the reliability of detecting the delamination in stacked-die packages. Therefore, a large portion of this paper focuses on the Q-BAM and Zip-Slice data acquisition and image interpretation.

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High temperature mechanical properties of Inconel 718 pulsed Nd–YAG laser welds

Materials at High Temperatures ◽

10.3184/096034006782739439 ◽

2006 ◽

Vol 23 (1) ◽

pp. 29-37 ◽

Cited By ~ 2

Author(s):

G.D. Janaki Ram ◽

A. Venugopal Reddy ◽

K. Prasad Rao ◽

G. Madhusudhan Reddy

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Inconel 718 ◽

Yag Laser ◽

High Temperature Mechanical Properties ◽

Laser Welds

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Vibrating sample method for amplitude and phase measurements with the acoustic microscope

Electronics Letters ◽

10.1049/el:19880859 ◽

1988 ◽

Vol 24 (20) ◽

pp. 1262

Author(s):

M.G. Somekh ◽

D. Zhang ◽

J.M. Rowe

Keyword(s):

Acoustic Microscope ◽

Phase Measurements ◽

Sample Method

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