Predicting the Shear Strength of a Wire Bond Using Laser Vibration Measurements

Effects of Bond Pad Thickness on Shear Strength of Copper Wire Bonds

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/2380-4491.2017.hiten.68 ◽

2017 ◽

Vol 2017 (HiTEN) ◽

pp. 000068-000073 ◽

Cited By ~ 2

Author(s):

Subramani Manoharan ◽

Chandradip Patel ◽

Stevan Hunter ◽

Patrick McCluskey

Keyword(s):

Shear Strength ◽

Shear Test ◽

Failure Modes ◽

High Reliability ◽

Copper Wire ◽

Test Method ◽

Ball Bond ◽

Wire Bond ◽

Industry Standards ◽

Wire Bonds

Abstract Copper (Cu) wire bonding is now widely accepted as a replacement for gold (Au), however, its use in high reliability applications is limited due to early failures in high temperature and humid conditions. The Au to Cu wire transition is mainly driven by cost savings though there are other advantages to Cu such as better electrical and thermal conductivity, slower intermetallic compound (IMC) formation and reduced wire sweep during transfer molding. Some automotive, industrial and aerospace industries are still reluctant to adopt Cu wire bonded products due to perceived risks of wire and bond pad cracks, the potential for corrosion, and some lack of understanding about its reliability in harsh conditions. A wire bond is considered good if destructive sampling qualification tests and periodic monitors pass for the batch. Tests include wire pull strength, wire bond shear, IMC coverage, and thickness of bond pad aluminum (Al) remaining beneath the bond. Nondestructive inspections also verify acceptable ball diameter and Al “splash”. This paper focuses on the bond shear test and its contribution to Cu ball bond reliability assessment, especially when changing Al bond pad thickness. A new revision of the JEDEC Wire Bond Shear Test Method, JESD22-B116B, has just been released, to include Cu wirebonds for the first time. It helps to clarify shear test failure modes for Cu ball bonds. However, there are still questions to be answered through research and experimentation, especially to learn the extent to which one may predict Cu ball bond reliability based on shear test results. Pad Al thickness is not considered in the current industry standards for shear test. Yet bond pad Al thickness varies widely among semiconductor products. This research is intended to contribute toward improved industry standards. In this study, power and time bonding parameters along with bond pad thickness are studied for bond strength. Several wire bonds are created at different conditions, evaluated by optical microscope and SEM, IMC% coverage and bond shear strength. Similar bonding conditions are repeated for bond pads of 4um, 1um and 0.5um thickness.

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Holding Power of Orthopaedic Screws in Metacarpal and Metatarsal Bones of Young Calves

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1633077 ◽

1992 ◽

Vol 05 (03) ◽

pp. 100-103 ◽

Cited By ~ 4

Author(s):

G. Jean ◽

J. K. Roush ◽

R. M. DeBowes ◽

E. M. Gaughan ◽

J. Kirpensteijn

Keyword(s):

Shear Strength ◽

Tensile Load ◽

Young Female ◽

Limiting Factor ◽

Holding Power ◽

Metatarsal Bones ◽

Bone Width ◽

Load To Failure ◽

Holstein Calves

SummaryThe holding power and holding power per mm bone width of 4.5 mm and 5.5 mm cortical and 6.5 mm cancellous orthopaedic screws were obtained by tensile load-to-failure studies in excised metacarpal and metatarsal bones of young female Holstein calves. Holding power and holding power per mm bone width of 6.5 mm orthopaedic screws were significantly greater than those of 4.5 and 5.5 mm orthopaedic screws in the diaphysis and metaphysis. Significant differences were not detected between holding power and holding power per mm bone width of 4.5 and 5.5 mm orthopaedic screws. The holding power was not different between metacarpi and metatarsi. The limiting factor in all tests of holding power was the shear strength of the bone. We found that 6.5 mm orthopaedic screws have the greatest holding power in the metacarpal and metatarsal bones of young calves.This study compares the holding power of 4.5 mm and 5.5 mm cortical and 6.5 mm cancellous orthopaedic screws in excised metacarpal and metatarsal bones from young female Holstein calves. We found that 6.5 mm orthopaedic screws have the greatest holding power.

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The Fully Softened Shear Strength of Lake Agassiz Clays

Geo-Congress 2020 ◽

10.1061/9780784482797.018 ◽

2020 ◽

Author(s):

Iván A. Contreras ◽

Jed D. Greenwood ◽

Aaron T. Grosser

Keyword(s):

Shear Strength ◽

Lake Agassiz ◽

Fully Softened Shear Strength

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Influence of anatomy on the adhesion performance of four wood species

Research Society and Development ◽

10.33448/rsd-v9i4.2727 ◽

2020 ◽

Vol 9 (4) ◽

pp. e31942727

Author(s):

João Gabriel Missia da Silva ◽

Pedro Nicó de Medeiros ◽

Denise Ransolin Soranso ◽

Vinicius Peixoto Tinti ◽

José Tarcísio da Silva Oliveira ◽

...

Keyword(s):

Shear Strength ◽

Specific Gravity ◽

Wood Species ◽

Tectona Grandis ◽

Glue Line ◽

Anatomical Characteristics ◽

Ray Cells ◽

Adhesion Performance ◽

Adhesion Process

The aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.

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