Deterioration mechanisms of fill material under the action of chlorine salt erosion and dry–wet cycles

2021 ◽  
Vol 14 (14) ◽  
Author(s):  
Hao Li ◽  
Yin Liu ◽  
Haifeng Wu ◽  
Wenjing Hu ◽  
Sen Chen
Keyword(s):  
Fill Material

The Use of Precision Selective Area Milling for Failure Analysis of Flip-Chip Packages

2002 ◽  
Author(s):  
George F. Gaut
Keyword(s):  
Failure Analysis ◽  
Flip Chip ◽  
Solder Bump ◽  
Selective Area ◽  
Fill Material ◽  
Solder Bumps ◽  
Time Required

Abstract Access to the solder bump and under-fill material of flip-chip devices has presented a new problem for failure analysts. The under-fill and solder bumps have also added a new source for failure causes. A new tool has become available that can reduce the time required to analyze this area of a flip-chip package. By using precision selective area milling it is possible to remove material (die or PCB) that will allow other tools to expose the source of the failure.

Microhardness Testing on Via Fill Material for Via In Pad Technology

2003 ◽  
Author(s):  
Norman J. Armendariz ◽  
Carolyn McCormick
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Strong Dependence ◽  
Circuit Board ◽  
Electrical Performance ◽  
Gravimetric Analysis ◽  
Passive Components ◽  
Root Cause ◽  
Fill Material ◽  
Signal Routing

Abstract Via in pad PCB (Printed Circuit board) technology for passive components such as chip capacitors and resistors, provides the potential for improved signal routing density and reduced PCB area. Because of these improvements there is the potential for PCB cost reduction as well as gains in electrical performance through reduced impedance and inductance. However, not long after the implementation, double digit unit failures for solder joint electrical opens due to capacitor “tombstoning” began to occur. Failure modes included via fill material (solder mask) protrusion from the via as well as “out gassing” and related “tombstoning.” This failure analysis involved investigating a strong dependence on PCB supplier and, less obviously, manufacturing site. Other factors evaluated included via fill material, drill size, via fill thermal history and via fill amount or fill percent. The factor most implicated was incomplete cure of the via fill material. Previous thermal gravimetric analysis methods to determine level of polymerization or cure did not provide an ability to measure and demonstrate via fill cure level in small selected areas or its link to the failures. As a result, there was a metrology approach developed to establish this link and root-cause the failures in the field, which was based on microhardness techniques and noncontact via fill measuring metrologies.

Note on a Fill Material for Water Sensitive Objects

1986 ◽  
Vol 25 (2) ◽  
pp. 93 ◽  
Author(s):  
Pamela Hatchfield
Keyword(s):  
Fill Material

scholarly journals Microscopic Mechanism Affecting Shear Strength in Lignin-Treated Loess Samples

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Wei Liu ◽  
Juan Wang ◽  
Gaochao Lin ◽  
Li Wen ◽  
Qian Wang
Keyword(s):  
Shear Strength ◽  
Lignin Content ◽  
Axial Stress ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Triaxial Tests ◽  
Microscopic Mechanism ◽  
Valley Fill ◽  
Fill Material ◽  
Excess Pore

In China, engineers have worked to create additional usable land for building construction by flattening the ridges of hills and filling in the adjacent valleys. China’s Loess Plateau comprises a type of soil (loess) with a large pore structure that can collapse and become unstable when exposed to groundwater. Conventional valley fill materials include remolded loess or remolded loess treated with cement, lime, gypsum, or other stabilizing additives. These stabilizers are often detrimental to the surrounding environment. Moreover, loess treated with conventional stabilizers exhibits excessive brittleness, which is not suitable for building foundations. Adequate stability of the building foundations in the filled valleys is required to ensure public safety. In this study, we tested 50 remolded loess samples treated with a lignin polymer compound to determine its potential as a valley fill material. Triaxial tests, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to study the mechanical characteristics of each sample, determine the effects of the lignin treatment on the loess, and identify the microscopic mechanism affecting shear stress in the lignin-treated loess. The corresponding development of excess pore pressure and volumetric responses under monotonic triaxial testing were also considered. Based on this study’s results, the optimum lignin content in the treated loess samples was 4%; lignin contents exceeding 4% decreased axial stress and increased dilation after saturation. The shear strength and strain-hardening phenomenon of the lignin-treated loess samples increased as the lignin content increased, while the excess pore water pressure decreased. Microscopically, the addition of lignin increased cohesion in the loess samples, while slightly contributing to the internal friction angle. The use of lignin as a stabilizing additive for valley fill material shows potential for controlling building foundation deformation by increasing soil strength and minimizing environmental impacts by maintaining the soil pH and limiting pollutant production.

Investigation of tire derived aggregate as a fill material for highway embankment

2013 ◽  
Vol 8 (2) ◽  
pp. 182-190 ◽  
Author(s):  
Daniel Meles ◽  
Alireza Bayat ◽  
Mohammad Hussien Shafiee ◽  
Somayeh Nassiri ◽  
Mustafa Gul
Keyword(s):  
Fill Material ◽  
Tire Derived Aggregate ◽  
Highway Embankment

Effectiveness of Geophysical Methods in Calcareous Harbor Fills

2013 ◽  
Author(s):  
Horst G. Brandes
Keyword(s):  
Ground Penetrating Radar ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Fill Material ◽  
Object Locations ◽  
Ground Penetrating

The effectiveness of electromagnetic (EM), ground penetrating radar (GPR) and seismic refraction (SR) were evaluated by surveying a shallow trench in which a number of objects of varying composition and size were buried. The trench was excavated in granular calcareous fill material. An experienced geophysical contractor was asked to provide blind predictions of object locations using each of the techniques in turn. GPR with a 400 MHz antenna was the most successful, followed by SR and EM surveying. GPR and SR were also carried out at the port of Hilo to investigate complex subsurface conditions.

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