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25 (07.9.15)
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The effect of ramp rate on temperature cycle fatigue in solder joints |
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Abstract
Following the enactment of international standards, unprecedented attention has become focused on the ramp rate of Temperature Cycle Tests. We have performed comparative testing to determine the life and failure mode of solder joints, investigating solder joints used on BGA and QFP packages. |
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18 (04.10.1)
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Evaluating the bonding and insulation
characteristics of conductive adhesives |
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Abstract
The advantages of low-temperature mounting and environmentally friendly attributes
have propelled conductive adhesives to the forefront in thes earch
for next-generation mounting technology to replace conventional solder
mounting. The widespread interest in this technology has led us to
prepare this report studying the reliability of conductive adhesives.
We ran temperature cycle tests to evaluate the bonding characteristics
of these adhesives, and we ran humidity and ionic migration (also
known as electrochemical migration) tests to evaluate insulation
reliability. The results we obtained under these experimental conditions
indicate that conductive adhesives offer both bonding reliability
and insulation reliability on a par with the reliability of conventional |
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17 (04.4.1)
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Destruction mechanisms resulting from vibration load in PCB-mounted electronics |
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Abstract
This report will present methods of quantifying and clarifying failure modes
that occur during the resonance vibration with the greatest increase in vibration
stress for vehicle-mounted devices that endure high levels of vibration. |
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11 (01.4.1)
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The occurrence of tracking in Printed Circuit Boards using organic insulating materials |
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Abstract
Accidents due
to tracking can cause fires, and examples of such accidents are continually occurring.
Various test standards exist for evaluation, but complex factors are involved, and
countermeasures cannot be obtained for all factors. We have investigated the effects of
the basic factors related to the occurrence of tracking, and we shall present the results of
our investigation in this report. |
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7 (99.3.31)
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An analysis of solder cracking mechanisms |
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Abstract
This report looks at one cause of solder cracking?the roughening of the solder grain
boundary field?and verifies the relation of the problem to both thermal and mechanical
stress. The results indicate that the solder grain boundary experiences roughening from
both types of stress, although thermal stress exerts the greater influence. Degradation
of solder strength due to roughening was also confirmed. |
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3 (97.4.1)
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Confirming Reliability of Printed Circuit Boards with Temperature Cycle and Thermal Shock |
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Abstract
In this report, to confirm the effects of heat stress on PCB through holes, we
performed the Temperature Cycle Test (air chamber method) and the Thermal Shock
Test (liquid bath method). As a result, we found a strong relationship between solder
cracking and the life of the copper-plated through hole. In addition, we shall report on
our confirmation of the mechanism leading to that failure life. |
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3 (97.4.1)
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The Mechanism of Solder Cracking |
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Abstract
In this paper we shall
report on reliability testing to confirm the mechanism of solder cracking due to heat
stress.
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