Reliability Impacts on Flip Chip Packages: Moisture Resistance, Mechanical Integrity and Photo-Sensitive Polyimide (PSPI) Passivation

2020 ◽  
Vol 12 (4) ◽  
pp. 577-582
Author(s):  
Gun Rae Kim ◽  
Sang-Su Ha ◽  
Sangwoo Pae ◽  
Jongwoo Park ◽  
Byoungdeog Choi
Keyword(s):  
Flip Chip ◽  
Moisture Absorption ◽  
Degradation Mechanism ◽  
Theoretical Explanation ◽  
Moisture Resistance ◽  
Mechanical Integrity ◽  
Before And After ◽  
Chip Scale Package ◽  
Cte Mismatch ◽  
Property Changes

In this paper, the effects of moisture sensitivity during preconditioning (30 °C/60% RH, 192 hours) tests and material property changes after reliability stressing on flip chip chip-scale package (FCCSP) were comprehensively investigated by various experimental data as well as theoretical explanation. Since the integrity of FCCSP is dependent on the mechanical integrity of underfill and PCB used in package assembly process, deep insight was given on the material properties in order to understand degradation mechanism induced by the combined stresses of preconditioning test and environmental stresses in a sequence. As a result of DOE (Design of Experiment) for 2 different PCB, failures were found only in J PCB because of a large CTE change before and after moisture absorption. After moisture absorption, large CTE change from 27.78 to 32.04 of J PCB could aggravate the thermal mismatch between a PCB and an underfill, it caused shear displacement by more than 2,309 ppm in the interface. According to the DOE for underfill, we verified that higher modulus underfill could improve the reliability of flip chip packages. Based on our works, we recommend the optimized value for underfill modulus is from 8 GPa to 12 GPa. We explained logically two different failure mechanisms of delamination. One is induced by CTE mismatch of PCB, and the other is by underfill modulus by means of electron microscope. Finally, as to reliability concerns of moisture resistance arisen from the absence of the photo-sensitive polyimide (PSPI) passivation layer, we demonstrated that potential risk is minimal if FCCSP is assembled with an appropriate underfill as well as PCB.

Effects of Backside Circuit Edit on Transistor Characteristics

2007 ◽  
Author(s):  
R.K. Jain ◽  
T. Malik ◽  
T.R. Lundquist ◽  
Q.S. Wang ◽  
R. Schlangen ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Flip Chip ◽  
Intrinsic Parameters ◽  
Chip Type ◽  
Device Structures ◽  
Before And After ◽  
Silicon Device ◽  
Metal Layers

Abstract Backside circuit edit techniques on integrated circuits (ICs) are becoming common due to increase number of metal layers and flip chip type packaging. However, a thorough study of the effects of these modifications has not been published. This in spite of the fact that the IC engineers have sometimes wondered about the effects of backside circuit edit on IC behavior. The IC industry was well aware that modifications can lead to an alteration of the intrinsic behavior of a circuit after a FIB edit [1]. However, because alterations can be controlled [2], they have not stopped the IC industry from using the FIB to successfully reconfigure ICs to produce working “silicon” to prove design and mask changes. Reliability of silicon device structures, transistors and diodes, are investigated by monitoring intrinsic parameters before and after various steps of modification.

Investigation of the properties of knitted woolen fabrics treated with oxygen low-temperature plasma for sportswear applications

2021 ◽  
pp. 004051752110306
Author(s):  
Honglian Cong ◽  
Boyu Zhao ◽  
Hao Han ◽  
Xuliang Yu
Keyword(s):  
Low Temperature ◽  
Plasma Treatment ◽  
Moisture Absorption ◽  
Mapping Method ◽  
Function Evaluation ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Wool Fibers ◽  
Before And After ◽  
Concentration Mapping

Nine groups of knitted woolen fabrics for sportswear with different technical characteristics were treated with oxygen low-temperature plasma, and the changes in the surface morphology and chemical composition of wool fibers before and after plasma treatment, as well as the changes in the applicability indexes of knitted woolen fabrics, were studied. Finally, the comfort performance of the fabrics was evaluated by combining the concentration mapping method and the function evaluation value method. The analysis found that the surface scales of wool fibers were seriously etched after oxygen low-temperature plasma treatment, and the anti-felting, bursting strength and moisture absorption of the knitted woolen fabrics were improved. At the same time, the quick-drying index of the fabric has also been improved to a certain extent. This research provides a basis for the development of knitted woolen fabric for sportswear with excellent performance.

Anomalous Scatter of Forward Current-Voltage Characteristics of He+-Irradiated Ni/4H-SiC Schottky Diodes

2016 ◽  
Vol 858 ◽  
pp. 749-752 ◽  
Author(s):  
Anatoly M. Strel'chuk ◽  
Viktor V. Zelenin ◽  
Alexei N. Kuznetsov ◽  
Joseph Tringe ◽  
Albert V. Davydov ◽  
...  
Keyword(s):  
Series Resistance ◽  
Degradation Mechanism ◽  
Schottky Diodes ◽  
Defect Structures ◽  
Induced Current ◽  
Forward Current ◽  
Current Voltage ◽  
Before And After ◽  
Current Voltage Characteristics

A study of forward current-voltage characteristics of Ni/4H-SiC Schottky diodes (SDs) before and after irradiation with He+ ions revealed features that characterize defect structures and reveal the degradation mechanism of the diodes. These features are the presence of excess currents of certain type in the unirradiated SDs, their appearance in forward-biased originally ideal SDs, and a >10 orders of magnitude scatter of the series resistance of the SDs upon their irradiation with He+ ions. A model of localized defect-induced current paths (shunts) in the form of unintentionally produced SDs with the substrate is suggested.

Nonlinear-Time-Dependent Analysis of Micro Via-In-Pad Substrates for Solder Bumped Flip Chip Applications

2002 ◽  
Vol 124 (3) ◽  
pp. 205-211 ◽  
Author(s):  
John H. Lau ◽  
S. W. Ricky Lee ◽  
Stephen H. Pan ◽  
Chris Chang
Keyword(s):  
Cross Sections ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Circuit Board ◽  
Test Results ◽  
Pcb Assembly ◽  
Creep Analysis ◽  
Chip Scale Package ◽  
Time Dependent Analysis

An elasto-plastic-creep analysis of a low-cost micro via-in-pad (VIP) substrate for supporting a solder bumped flip chip in a chip scale package (CSP) format which is soldered onto a printed circuit board (PCB) is presented in this study. Emphasis is placed on the design, materials, and reliability of the micro VIP substrate and of the micro VIP CSP solder joints on PCB. The solder is assumed to obey Norton’s creep law. Cross-sections of samples are examined for a better understanding of the solder bump, CSP substrate redistribution, micro VIP, and solder joint. Also, the thermal cycling test results of the micro VIP CSP PCB assembly is presented.

Studies on the Property Changes of Environmental Degradation Mulching Film and Polyethylene Mulching Film in Water Environment

2012 ◽  
Vol 268-270 ◽  
pp. 241-244
Author(s):  
Bin Bin Zhao ◽  
Xue Gang Luo ◽  
Xiao Yan Lin ◽  
Hong Ping Zhang
Keyword(s):  
Environmental Degradation ◽  
Water Environment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polyethylene Mulching ◽  
Before And After ◽  
Diffraction Peaks ◽  
Property Changes ◽  
Mulching Film

This paper studied the property changes of environmental degradation mulching film and polyethylene mulching film in water environment. The XRD (X-ray diffraction) cures showed that the diffraction angles of environmental degradation mulching film were not changed but intensities and area of diffraction peaks increased after immersion for 60 days; while the diffraction angles and area of diffraction peaks of polyethylene mulching film were same before and after immersion. Cracks and holes appeared in surface of environmental degradation mulching film, but it was still smooth and uniform for the polyethylene mulching film after immersion.

scholarly journals Influence of Furfuryl Alcohol Fiber Pre-Treatment on the Moisture Absorption and Mechanical Properties of Flax Fiber Composites

Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 59 ◽  
Author(s):  
Yunlong Jia ◽  
Bodo Fiedler
Keyword(s):  
Mechanical Properties ◽  
Furfuryl Alcohol ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Tensile Tests ◽  
Fiber Composites ◽  
Flax Fiber ◽  
Moisture Resistance ◽  
Structural Applications ◽  
Pre Treatment

Poor moisture resistance of natural fiber reinforced bio-composites is a major concern in structural applications. Many efforts have been devoted to alleviate degradation of bio-composites caused by moisture absorption. Among them, fiber pre-treatment has been proven to be effective. This paper proposes an alternative “green” fiber pretreatment with furfuryl alcohol. Pre-treatments with different parameters were performed and the influence on the mechanical properties of fiber bundles and composites was investigated. Moisture resistance of composites was evaluated by water absorption tests. Mechanical properties of composites with different water contents were analyzed in tensile tests. The results show that furfuryl alcohol pretreatment is a promising method to improve moisture resistance and mechanical properties (e.g., Young’s modulus increases up to 18%) of flax fiber composites.

Effect of Design Factors on Microvia Reliability of Flip Chip Ball Grid Array Polymeric Substrates

2008 ◽  
Vol 5 (3) ◽  
pp. 104-115
Author(s):  
Dennis Leung ◽  
Guna Selvaduray
Keyword(s):  
Electrical Resistance ◽  
High Performance ◽  
Flip Chip ◽  
Ball Grid Array ◽  
Temperature Cycling ◽  
Low Aspect Ratio ◽  
Cte Mismatch ◽  
Polymeric Substrates ◽  
Design Factors ◽  
The Relationship

Microvia failures in flip chip ball grid array (FCBGA) polymeric substrates have been a major concern in the development of reliable packages for high-performance and high-density chips. To determine the relationship between reliability and design factors of the microvias, a 10-layer substrate was used to investigate these contrasting design factors: “stack-on-core” vs. “non–stack-on-core,” “high” vs. “low” aspect ratio, “stacked” vs. “staggered,” and “fillet” vs. “non-fillet.” Temperature cycling was used to generate stresses on the microvias. Electrical resistance was measured and analyzed, using design of experiment (DOE), to determine the effects of these design factors on microvia reliability. The significant single factors for a robust microvia were “non–stack-on-core” and “staggered.” Cross-sectioning was employed to understand the failure pattern. Cracks occurred on “stack-on-core” and “stacked” designs only. All the cracks were located at the interface between the capture pad and the bottom of the microvia, where stress is the highest due to the CTE mismatch of different materials.

Creating Semiconductor Value through Advanced Package Technology

2016 ◽  
Vol 2016 (S1) ◽  
pp. S1-S46
Author(s):  
Ron Huemoeller
Keyword(s):  
Big Five ◽  
Flip Chip ◽  
Microelectromechanical Systems ◽  
Technology Innovation ◽  
Low Cost ◽  
Semiconductor Industry ◽  
Significant Shift ◽  
Wafer Level ◽  
Chip Scale Package ◽  
Advanced Packaging

Over the past few years, there has been a significant shift from PCs and notebooks to smartphones and tablets as drivers of advanced packaging innovation. In fact, the overall packaging industry is doing quite well today as a result, with solid growth expected to create a market value in excess of $30B USD by 2020. This is largely due to the technology innovation in the semiconductor industry continuing to march forward at an incredible pace, with silicon advancements in new node technologies continuing on one end of the spectrum and innovative packaging solutions coming forward on the other in a complementary fashion. The pace of innovation has quickened as has the investments required to bring such technologies to production. At the packaging level, the investments required to support the advancements in silicon miniaturization and heterogeneous integration have now reached well beyond $500M USD per year. Why has the investment to support technology innovation in the packaging community grown so much? One needs to look no further than the complexity of the most advanced package technologies being used today and coming into production over the next year. Advanced packaging technologies have increased in complexity over the years, transitioning from single to multi-die packaging, enabled by 3-dimensional integration, system-in-package (SiP), wafer-level packaging (WLP), 2.5D/3D technologies and creative approached to embedding die. These new innovative packaging technologies enable more functionality and offer higher levels of integration within the same package footprint, or even more so, in an intensely reduced footprint. In an industry segment that has grown accustomed to a multitude of package options, technology consolidation seems evident, producing “The Big Five” advanced packaging platforms. These include low-cost flip chip, wafer-level chip-scale package (WLCSP), microelectromechanical systems (MEMS), laminate-based advanced system-in-package (SiP) and wafer-based advanced SiP designs. This presentation will address ‘The Big Five’ packaging platforms and how they are adding value to the Semiconductor Industry.

Finite Element Analysis of Laser Fabricated Microjoint Performance in Cerebrospinal Fluid

2007 ◽  
Author(s):  
Ahsan Mian ◽  
Jesse Law
Keyword(s):  
Finite Element ◽  
Cerebrospinal Fluid ◽  
Mechanical Performance ◽  
Degradation Mechanism ◽  
Polyimide Film ◽  
Element Analysis ◽  
Critical Feature ◽  
Artificial Cerebrospinal Fluid ◽  
Bond Degradation ◽  
Before And After

Assessment of neural biocompatibility requires that materials be tested with exposure in neural fluids. Laser bonded microjoint samples made from titanium foil and polyimide film (TiPI) were evaluated for mechanical performance before and after exposure in artificial cerebrospinal fluid (CSF) for two, four and twelve weeks at 37°C. These samples represent a critical feature i.e., the microjoint — a major weakness in the bioencapsulation system. The laser microbonds showed initial degradation up to four weeks which then stabilized afterwards and retained similar strength until twelve weeks. To understand this bond degradation mechanism better, a finite element modeling approach was adopted. From the finite element results, it was revealed that the bond degradation was not owing to the hygroscopic expansion of polyimide. Rather, relaxation of the process induced residual stresses may have resulted in weakening of the bond strength as observed from experimental measurements.

Hygro-Mechanical Durability of Underfilled Flip-Chip-on-Board (FCOB) Interconnects

2002 ◽  
Vol 124 (3) ◽  
pp. 184-187 ◽  
Author(s):  
J. H. Okura ◽  
A. Dasgupta ◽  
J. F. J. M. Caers
Keyword(s):  
Flip Chip ◽  
Failure Modes ◽  
Moisture Absorption ◽  
Accelerated Aging ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Service Durability ◽  
Mechanical Durability ◽  
Life Tests ◽  
And Diffusion

The effect of constant temperature and humidity environments on the durability of interconnects in underfilled Flip-Chip-on-Board (FCOB) assemblies is investigated in this study. Polymeric underfills, used to enhance thermomechanical durability of the interconnects, are found to create new failure modes due to hygromechanical swelling. Based on experimental observations, the failure mechanism is hypothesized to be cracking of intermetallics, which have weakened due to thermal aging. Pseudo 3-D finite element analyses are conducted to quantify the moisture absorption and diffusion through the polymeric underfill, and the resulting hygromechanical viscoplastic stress history. The simulations are combined with accelerated aging tests to assess in-service durability in hot, humid environments. Model predictions are compared with results of accelerated life tests available in the literature.

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