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Y. Li and D. Goyal
fabrication technology evolution, along with general recommendations in selecting
and applying appropriate material and process technologies for 3D packaging.
1.4.4 Quality, Reliability and Failure Analysis Challenges
Complex 3D packages have multiscale interconnects ranging from a few micrometers to 1000 micrometers. For instance, TSVs and micro-bumps are about a couple
of micrometer in diameters, while the SLI connecting packages to the PCB could
be up to 1000 µm in diameter. During 3D integration, interconnects need to go
through multiple solder reflow process, defects generated during fabrication and
assembly, CTE mismatch between different materials, and microstructure evolution
in interconnects could lead to new quality and reliability issues. Additionally, the
extended application of 3D packaging in products requiring much higher reliability,
for instance, Advanced Driver Assistance Systems (ADAS), avionics, and high-end
servers brings extra challenges to the quality and reliability of 3D packages. Chapters 3–6 review the quality and reliability of TSVs. Chapter 12 reviews the electro
migration concerns in interconnects of 3D packages. Focusing on the reliability of
multi-level solder joints in stacked packages, Chap. 16 explains the different reliability requirements between consumer electronics and high-reliability electronics. It
also provides detailed discussions of use conditions, the roles of encapsulants and
underfills, reliability tests and modeling to address complex reliability concerns in 3D
packages. Chapter 17 provides an overview of quality and reliability of 3D packaging
and demonstrates with case studies, along with field performance prediction.
Failure analysis is critical for the technology development of 3D packaging, as
in-depth root cause analysis of failures provides solution paths for resolving quality
and reliability issues. Due to the complexity of 3D packages, Fault Isolation (FI) and
Failure analysis (FA) become very challenging. First of all, multiple failures could
exist in one unit post reliability tests, flawless failure analysis on each failure requires
non-destructive high resolution techniques, including fault isolation, imaging, and
material analysis. Additionally each electrical failure in a 3D package could come
from various dice, assembly layers or interconnects, high resolution fault isolation
techniques, which could provide three dimensional information of defects are highly
desired. After the identification of defects, physical failure analysis needs to be
performed for the root cause study. However interconnects in 3D packages, like
TSVs, have small diameters (2–10 µm) and long lengths (40–200 µm), artifact
free cross section techniques with short through-put time is critical for characterizing small defects in a relatively large cross sectional plane. Chapter 18 reviews
advanced high resolution non-destructive FI and FA techniques, such as Electro
Optic Terahertz Pulse Reflectometry (EOTPR), 3D X-ray Computed Tomography
(CT), Lock-in Thermography (LIT), and acoustic microscopy. The applications of
novel physical sample preparation techniques and various material analysis methods
in 3D packaging failure analysis are also discussed. It also provides guidelines for
Y. Li and D. Goyal
fabrication technology evolution, along with general recommendations in selecting
and applying appropriate material and process technologies for 3D packaging.
1.4.4 Quality, Reliability and Failure Analysis Challenges
Complex 3D packages have multiscale interconnects ranging from a few micrometers to 1000 micrometers. For instance, TSVs and micro-bumps are about a couple
of micrometer in diameters, while the SLI connecting packages to the PCB could
be up to 1000 µm in diameter. During 3D integration, interconnects need to go
through multiple solder reflow process, defects generated during fabrication and
assembly, CTE mismatch between different materials, and microstructure evolution
in interconnects could lead to new quality and reliability issues. Additionally, the
extended application of 3D packaging in products requiring much higher reliability,
for instance, Advanced Driver Assistance Systems (ADAS), avionics, and high-end
servers brings extra challenges to the quality and reliability of 3D packages. Chapters 3–6 review the quality and reliability of TSVs. Chapter 12 reviews the electro
migration concerns in interconnects of 3D packages. Focusing on the reliability of
multi-level solder joints in stacked packages, Chap. 16 explains the different reliability requirements between consumer electronics and high-reliability electronics. It
also provides detailed discussions of use conditions, the roles of encapsulants and
underfills, reliability tests and modeling to address complex reliability concerns in 3D
packages. Chapter 17 provides an overview of quality and reliability of 3D packaging
and demonstrates with case studies, along with field performance prediction.
Failure analysis is critical for the technology development of 3D packaging, as
in-depth root cause analysis of failures provides solution paths for resolving quality
and reliability issues. Due to the complexity of 3D packages, Fault Isolation (FI) and
Failure analysis (FA) become very challenging. First of all, multiple failures could
exist in one unit post reliability tests, flawless failure analysis on each failure requires
non-destructive high resolution techniques, including fault isolation, imaging, and
material analysis. Additionally each electrical failure in a 3D package could come
from various dice, assembly layers or interconnects, high resolution fault isolation
techniques, which could provide three dimensional information of defects are highly
desired. After the identification of defects, physical failure analysis needs to be
performed for the root cause study. However interconnects in 3D packages, like
TSVs, have small diameters (2–10 µm) and long lengths (40–200 µm), artifact
free cross section techniques with short through-put time is critical for characterizing small defects in a relatively large cross sectional plane. Chapter 18 reviews
advanced high resolution non-destructive FI and FA techniques, such as Electro
Optic Terahertz Pulse Reflectometry (EOTPR), 3D X-ray Computed Tomography
(CT), Lock-in Thermography (LIT), and acoustic microscopy. The applications of
novel physical sample preparation techniques and various material analysis methods
in 3D packaging failure analysis are also discussed. It also provides guidelines for