Tests prove reliability of "chip-on-board" technology

Microelectronics International

ISSN: 1356-5362

Article publication date: 31 July 2007



(2007), "Tests prove reliability of "chip-on-board" technology", Microelectronics International, Vol. 24 No. 3. https://doi.org/10.1108/mi.2007.21824cab.007



Emerald Group Publishing Limited

Copyright © 2007, Emerald Group Publishing Limited

Tests prove reliability of "chip-on-board" technology

Tests prove reliability of "chip-on-board" technology

MCE Newmarket has undertaken an extensive programme of reliability tests to validate the performance of chip-on- board (COB) technology (Figure 3) for harsh environment applications.

Figure 3 An example of chip-on-board (COB)

COB technology involves mounting bare semiconductor chips directly onto the PCB. The chip and its wire bonded leads are then encapsulated in an appropriate medium such as an epoxy or silicone adhesive – so-called “glob topping”.

One of the main concerns about the implementation of COB technology is the reliability of glob-topped components in harsh environments. MCE Newmarket has developed new criteria for the evaluation of COB assemblies based on the BS9450 scheme for the certification of electronic components.

A comprehensive test programme has been undertaken on test circuits fabricated on high-temperature FR4 and flexi-rigid PCBs and ceramic substrates using both Pb-free and Pb- based solders and selected glob-top encapsulants. The tests performed included high-temperature storage, operation under rapid change of temperature and “damp heat” testing for representative industrial, telecoms and aerospace/defence environmental performance specifications.

The materials and assembly processes tested have passed all of the environmental tests for durations of at least 1,000h.

This data provides the assurance that COB technology can be applied in demanding applications, with specific advantages in space restricted systems.

MCE Newmarket – part of GE Aviation – is a leading supplier of high- reliability electronics for aerospace, defence, industrial, telecommunications, computer and medical applications. MCE Newmarket specialises in the design and manufacture of customised electronic modules.

This programme is just one example of the way that MCE Newmarket is responding to meet the needs of its end customers. Other programmes are in progress to transfer traditional hybrid technologies onto different substrate materials including low-temperature co-fired ceramic (LTCC) and insulated metal substrates (IMS), extending the frequency, temperature and power handling characteristics of hybrid microcircuits.

For further information on the high- reliability COB technology available at MCE Newmarket, please contact Steve Riches (E-mail: stever@mcenkt.co.uk)

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