578
Y. Li and D. Goyal
(~40–200 μm), artifact free cross section technique with short through-put time
(TPT) is critical for characterizing small defects in a relatively large cross sectional
area. Mechanical and conventional Focused Ion Beam (FIB) cross section techniques
do not meet the demands. Alternative artifact free cross section techniques, which
have a much higher milling rate while maintaining accurate cross section location
control are more promising for 3D package failure analysis.
Complicated 3D packages could have subtle defects, such as plating defects
in surface finish layers, contaminations at interfaces, impurities in interconnects,
crystal size and distribution abnormity in small interconnects. These subtle defects
could result in failures, like delamination, non-wets and cracks in interconnects
post assembly or reliability tests. Innovative applications of material analysis techniques, which could provide elemental, chemical state, depth profile, and crystallographic orientation of materials around the failing area are crucial to the root cause
investigation.
This chapter will discuss the advanced FI and FA techniques developed to address
FI-FA challenges in 3D packages, including high resolution non-destructive FI and
FA methods, advanced sample preparation and material analysis techniques, efficient
FI and FA flows, along with FA strategies and case studies to demonstrate their
applications in the failure analysis of 3D microelectronic packages.
18.3 The Application of Non-destructive FI and FA
Techniques to 3D Microelectronic Packages
18.3.1 Non-destructive Fault Isolation Techniques
for Electrical Failures in 3D Microelectronic Packages
Non-destructive fault isolation techniques are the key to reveal multiple failures in
a complex 3D package with shorter throughput time (TPT) and higher success rate.
Detailed discussions of four important FI techniques for 3D packages, including timedomain reflectometry (TDR), Electro Optic Terahertz Pulse Reflectometry (EOTPR),
Lock-In Thermography (LIT), and Scanning Superconducting Quantum Interference
Device (SQUID) Microscopy (SSM) are provided in this section. Table 18.1 summarizes the resolution, capability, Pros, and Cons of each technique. Depending on
package configurations, applications, TPT requirements, and budget limits, one or
more FI techniques could be selected for the FI of electrical failures in 3D packages.
18.3.1.1 Time-Domain Reflectometry (TDR)
For open and high resistance failures, time-domain reflectometry (TDR) and Electro
Optic Terahertz Pulse Reflectometry (EOTPR) have been proven to be very effective
in 3D packages [1]. TDR is a low cost and conventional non-destructive FI technique
Y. Li and D. Goyal
(~40–200 μm), artifact free cross section technique with short through-put time
(TPT) is critical for characterizing small defects in a relatively large cross sectional
area. Mechanical and conventional Focused Ion Beam (FIB) cross section techniques
do not meet the demands. Alternative artifact free cross section techniques, which
have a much higher milling rate while maintaining accurate cross section location
control are more promising for 3D package failure analysis.
Complicated 3D packages could have subtle defects, such as plating defects
in surface finish layers, contaminations at interfaces, impurities in interconnects,
crystal size and distribution abnormity in small interconnects. These subtle defects
could result in failures, like delamination, non-wets and cracks in interconnects
post assembly or reliability tests. Innovative applications of material analysis techniques, which could provide elemental, chemical state, depth profile, and crystallographic orientation of materials around the failing area are crucial to the root cause
investigation.
This chapter will discuss the advanced FI and FA techniques developed to address
FI-FA challenges in 3D packages, including high resolution non-destructive FI and
FA methods, advanced sample preparation and material analysis techniques, efficient
FI and FA flows, along with FA strategies and case studies to demonstrate their
applications in the failure analysis of 3D microelectronic packages.
18.3 The Application of Non-destructive FI and FA
Techniques to 3D Microelectronic Packages
18.3.1 Non-destructive Fault Isolation Techniques
for Electrical Failures in 3D Microelectronic Packages
Non-destructive fault isolation techniques are the key to reveal multiple failures in
a complex 3D package with shorter throughput time (TPT) and higher success rate.
Detailed discussions of four important FI techniques for 3D packages, including timedomain reflectometry (TDR), Electro Optic Terahertz Pulse Reflectometry (EOTPR),
Lock-In Thermography (LIT), and Scanning Superconducting Quantum Interference
Device (SQUID) Microscopy (SSM) are provided in this section. Table 18.1 summarizes the resolution, capability, Pros, and Cons of each technique. Depending on
package configurations, applications, TPT requirements, and budget limits, one or
more FI techniques could be selected for the FI of electrical failures in 3D packages.
18.3.1.1 Time-Domain Reflectometry (TDR)
For open and high resistance failures, time-domain reflectometry (TDR) and Electro
Optic Terahertz Pulse Reflectometry (EOTPR) have been proven to be very effective
in 3D packages [1]. TDR is a low cost and conventional non-destructive FI technique