The influence of temperature and humidity on printed wiring board surface finishes: Immersion tin vs organic azoles

1994 ◽  
Vol 23 (8) ◽  
pp. 779-785 ◽  
Author(s):  
U. Ray ◽  
I. Artaki ◽  
H. M. Gordon ◽  
P. T. Vianco
Keyword(s):  
Printed Wiring Board ◽  
Influence Of Temperature ◽  
Surface Finishes ◽  
Board Surface ◽  
Temperature And Humidity ◽  
Wiring Board ◽  
Immersion Tin

Investigating the Influence of Uneven Printed Wiring Board Surface on Volume Increment of Deposited Solder Pastes

2010 ◽  
Vol 2 (3) ◽  
pp. 163-169
Author(s):  
Oliver Krammer ◽  
Laszlo Milan Molnar ◽  
Laszlo Jakab ◽  
Andras Szabó
Keyword(s):  
Printed Wiring Board ◽  
Volume Increment ◽  
Board Surface ◽  
Solder Pastes ◽  
Wiring Board

Influence of Temperature on the Fatigue of CC/PWB Joints

1990 ◽  
Vol 33 (1) ◽  
pp. 17-25
Author(s):  
Harvey Solomon
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Hysteresis Loops ◽  
Cycle Fatigue ◽  
Printed Wiring Board ◽  
Influence Of Temperature ◽  
Joint Resistance ◽  
Influence Of Temperature On ◽  
Chip Carrier ◽  
Wiring Board

This is a study of the low cycle fatigue of chip carrier/ printed wiring board joints tested at -55° C (-67° F) and 125° C (257° F). It is contrasted to a previous study where the joints were tested at 35° C (95° F). The behavior at 35° C and 125° C was the same. Differences were noted, however, at -55° C. The hysteresis loops were distorted. The slopes of the displacement vs. fatigue life curves were slightly lower and the fatigue lives were longer. These differences were especially significant when the change in joint resistance was used to define failure.

Influence of Surface Mount Lead End Geometry on Fatigue Life

1994 ◽  
Vol 116 (2) ◽  
pp. 157-160 ◽  
Author(s):  
Vineet K. Gupta ◽  
Donald B. Barker
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Thermal Fatigue ◽  
Coefficient Of Thermal Expansion ◽  
Printed Wiring Board ◽  
Surface Mount ◽  
Compliant Surface ◽  
Board Surface ◽  
Cte Mismatch ◽  
Wiring Board

The local coefficient of thermal expansion (CTE) mismatch between compliant surface mount component leads and the solder that is used to attach the components to a printed wiring board can dramatically influence the thermal fatigue life of the solder joint. To quantify the contribution of the local CTE mismatch to the overall thermal fatigue damage of the solder joint, a finite element thermal fatigue simulation using an energy partitioning technique is used to compare four different lead end shapes. The four lead configurations considered are J-lead, and three gullwings leads; one with the foot parallel to the board surface, one with the foot sloped slightly downward towards the board, and one with the foot sloped slightly upward. The dimensions of the leads are purposely chosen so that the in-plane compliance is equal for the different lead shapes, only the shape of the lead end varied. Comparisons are first made with equal solder joint heights and then the solder height of the gull-wing lead is varied between 0.05 to 0.23 mm (2 to 9 mils). The influence of the solder wetting angle is also investigated.

Case Studies of Brittle Interfacial Failures in Area Array Solder Interconnects

2000 ◽  
Author(s):  
George M. Wenger ◽  
Richard J. Coyle ◽  
Patrick P. Solan ◽  
John K. Dorey ◽  
Courtney V. Dodd ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Case Studies ◽  
Failure Modes ◽  
Electroless Nickel ◽  
Electrical Performance ◽  
Printed Wiring Board ◽  
Solder Interconnects ◽  
Area Array ◽  
Surface Finishes ◽  
Soldering Reaction

Abstract A common pad finish on area array (BGA or CSP) packages and printed wiring board (PWB) substrates is Ni/Au, using either electrolytic or electroless deposition processes. Although both Ni/Au processes provide flat, solderable surface finishes, there are an increasing number of applications of the electroless nickel/immersion gold (ENi/IAu) surface finish in response to requirements for increased density and electrical performance. This increasing usage continues despite mounting evidence that Ni/Au causes or contributes to catastrophic, brittle, interfacial solder joint fractures. These brittle, interfacial fractures occur early in service or can be generated under a variety of laboratory testing conditions including thermal cycling (premature failures), isothermal aging (high temperature storage), and mechanical testing. There are major initiatives by electronics industry consortia as well as research by individual companies to eliminate these fracture phenomena. Despite these efforts, interfacial fractures associated with Ni/Au surface finishes continue to be reported and specific failure mechanisms and root cause of these failures remains under investigation. Failure analysis techniques and methodologies are crucial to advancing the understanding of these phenomena. In this study, the scope of the fracture problem is illustrated using three failure analysis case studies of brittle interfacial fractures in area array solder interconnects. Two distinct failure modes are associated with Ni/Au surface finishes. In both modes, the fracture surfaces appear to be relatively flat with little evidence of plastic deformation. Detailed metallography, scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and an understanding of the metallurgy of the soldering reaction are required to avoid misinterpreting the failure modes.

The Influence of Temperature and Humidity of Greenhouse Gas Emission in Experiments on Imitation of the Fuel Vegetation Cycle of the Tundra Ecosystems

2018 ◽  
Vol 483 (5) ◽  
pp. 535-537
Author(s):  
Yu. Barkhatov ◽  
◽  
A. Degermendzhi ◽  
A. Tikhomirov ◽  
S. Evgrafova ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Greenhouse Gas Emission ◽  
Gas Emission ◽  
Influence Of Temperature ◽  
Temperature And Humidity ◽  
Tundra Ecosystems
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