Bulk substrate porosity verification by applying Monte Carlo modeling and Castaing's formula using energy-dispersive x-rays

Lai Chin Yung, Cheong Choke Fei, Mandeep Singh Jit Singh, Nowshad Amin, Khin Wee Lai

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The leadframe fabrication process normally involves additional thin-metal layer plating on the bulk copper substrate surface for wire bonding purposes. Silver, tin, and copper flakes are commonly adopted as plating materials. It is critical to assess the density of the plated metal layer, and in particular to look for porosity or voids underneath the layer, which may reduce the reliability during high-temperature stress. A fast, reliable inspection technique is needed to assess the porosity or void weakness. To this end, the characteristics of x-rays generated from bulk samples were examined using an energy-dispersive x-ray (EDX) detector to examine the porosity percentage. Monte Carlo modeling was integrated with Castaing's formula to verify the integrity of the experimental data. Samples with different porosity percentages were considered to test the correlation between the intensity of the collected x-ray signal and the material density. To further verify the integrity of the model, conventional cross-sectional samples were also taken to observe the porosity percentage using Image J software measurement. A breakthrough in bulk substrate assessment was achieved by applying EDX for the first time to nonelemental analysis. The experimental data showed that the EDX features were not only useful for elemental analysis, but also applicable to thin-film metal layer thickness measurement and bulk material density determination. A detailed experiment was conducted using EDX to assess the plating metal layer and bulk material porosity.

Original languageEnglish
Article number061105
JournalJournal of Electronic Imaging
Volume24
Issue number6
DOIs
Publication statusPublished - 1 Nov 2015

Fingerprint

Porosity
porosity
X rays
Substrates
plating
Plating
x rays
metals
integrity
energy
voids
Metals
Copper
x ray detectors
copper
Thickness measurement
flakes
Tin
inspection
tin

Keywords

  • absorption
  • multilayers
  • thin films
  • x rays

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Science Applications
  • Atomic and Molecular Physics, and Optics

Cite this

Bulk substrate porosity verification by applying Monte Carlo modeling and Castaing's formula using energy-dispersive x-rays. / Yung, Lai Chin; Fei, Cheong Choke; Jit Singh, Mandeep Singh; Amin, Nowshad; Lai, Khin Wee.

In: Journal of Electronic Imaging, Vol. 24, No. 6, 061105, 01.11.2015.

Research output: Contribution to journalArticle

@article{c8bcd3437e324768a3ca457df91506e5,
title = "Bulk substrate porosity verification by applying Monte Carlo modeling and Castaing's formula using energy-dispersive x-rays",
abstract = "The leadframe fabrication process normally involves additional thin-metal layer plating on the bulk copper substrate surface for wire bonding purposes. Silver, tin, and copper flakes are commonly adopted as plating materials. It is critical to assess the density of the plated metal layer, and in particular to look for porosity or voids underneath the layer, which may reduce the reliability during high-temperature stress. A fast, reliable inspection technique is needed to assess the porosity or void weakness. To this end, the characteristics of x-rays generated from bulk samples were examined using an energy-dispersive x-ray (EDX) detector to examine the porosity percentage. Monte Carlo modeling was integrated with Castaing's formula to verify the integrity of the experimental data. Samples with different porosity percentages were considered to test the correlation between the intensity of the collected x-ray signal and the material density. To further verify the integrity of the model, conventional cross-sectional samples were also taken to observe the porosity percentage using Image J software measurement. A breakthrough in bulk substrate assessment was achieved by applying EDX for the first time to nonelemental analysis. The experimental data showed that the EDX features were not only useful for elemental analysis, but also applicable to thin-film metal layer thickness measurement and bulk material density determination. A detailed experiment was conducted using EDX to assess the plating metal layer and bulk material porosity.",
keywords = "absorption, multilayers, thin films, x rays",
author = "Yung, {Lai Chin} and Fei, {Cheong Choke} and {Jit Singh}, {Mandeep Singh} and Nowshad Amin and Lai, {Khin Wee}",
year = "2015",
month = "11",
day = "1",
doi = "10.1117/1.JEI.24.6.061105",
language = "English",
volume = "24",
journal = "Journal of Electronic Imaging",
issn = "1017-9909",
publisher = "SPIE",
number = "6",

}

TY - JOUR

T1 - Bulk substrate porosity verification by applying Monte Carlo modeling and Castaing's formula using energy-dispersive x-rays

AU - Yung, Lai Chin

AU - Fei, Cheong Choke

AU - Jit Singh, Mandeep Singh

AU - Amin, Nowshad

AU - Lai, Khin Wee

PY - 2015/11/1

Y1 - 2015/11/1

N2 - The leadframe fabrication process normally involves additional thin-metal layer plating on the bulk copper substrate surface for wire bonding purposes. Silver, tin, and copper flakes are commonly adopted as plating materials. It is critical to assess the density of the plated metal layer, and in particular to look for porosity or voids underneath the layer, which may reduce the reliability during high-temperature stress. A fast, reliable inspection technique is needed to assess the porosity or void weakness. To this end, the characteristics of x-rays generated from bulk samples were examined using an energy-dispersive x-ray (EDX) detector to examine the porosity percentage. Monte Carlo modeling was integrated with Castaing's formula to verify the integrity of the experimental data. Samples with different porosity percentages were considered to test the correlation between the intensity of the collected x-ray signal and the material density. To further verify the integrity of the model, conventional cross-sectional samples were also taken to observe the porosity percentage using Image J software measurement. A breakthrough in bulk substrate assessment was achieved by applying EDX for the first time to nonelemental analysis. The experimental data showed that the EDX features were not only useful for elemental analysis, but also applicable to thin-film metal layer thickness measurement and bulk material density determination. A detailed experiment was conducted using EDX to assess the plating metal layer and bulk material porosity.

AB - The leadframe fabrication process normally involves additional thin-metal layer plating on the bulk copper substrate surface for wire bonding purposes. Silver, tin, and copper flakes are commonly adopted as plating materials. It is critical to assess the density of the plated metal layer, and in particular to look for porosity or voids underneath the layer, which may reduce the reliability during high-temperature stress. A fast, reliable inspection technique is needed to assess the porosity or void weakness. To this end, the characteristics of x-rays generated from bulk samples were examined using an energy-dispersive x-ray (EDX) detector to examine the porosity percentage. Monte Carlo modeling was integrated with Castaing's formula to verify the integrity of the experimental data. Samples with different porosity percentages were considered to test the correlation between the intensity of the collected x-ray signal and the material density. To further verify the integrity of the model, conventional cross-sectional samples were also taken to observe the porosity percentage using Image J software measurement. A breakthrough in bulk substrate assessment was achieved by applying EDX for the first time to nonelemental analysis. The experimental data showed that the EDX features were not only useful for elemental analysis, but also applicable to thin-film metal layer thickness measurement and bulk material density determination. A detailed experiment was conducted using EDX to assess the plating metal layer and bulk material porosity.

KW - absorption

KW - multilayers

KW - thin films

KW - x rays

UR - http://www.scopus.com/inward/record.url?scp=84942626824&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84942626824&partnerID=8YFLogxK

U2 - 10.1117/1.JEI.24.6.061105

DO - 10.1117/1.JEI.24.6.061105

M3 - Article

AN - SCOPUS:84942626824

VL - 24

JO - Journal of Electronic Imaging

JF - Journal of Electronic Imaging

SN - 1017-9909

IS - 6

M1 - 061105

ER -