MCE takes lead in developing “chip on board” reliability criteria

Citation

(2006), "MCE takes lead in developing “chip on board” reliability criteria", Microelectronics International, Vol. 23 No. 3. https://doi.org/10.1108/mi.2006.21823cab.009

MCE takes lead in developing “chip on board” reliability criteria

MCE takes lead in developing “chip on board” reliability criteria

Keywords: Packaging industry, Electronics industry

MCE Newmarket, an established manufacturer of high reliability custom electronic modules, is taking the lead in developing new criteria within the BS 9450 series for “chip on board” components.

Chip on board (COB) technology involves mounting bare semiconductor chips directly onto the printed circuit board. 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.”

MCE is tackling concerns about the endurance of glob-topped components through a comprehensive programme of environmental testing. The tests include high temperature storage and operation under rapid change of temperature and at high temperature and humidity. The programme will provide reliability data to give end-users more confidence in utilising this technology in demanding applications.

The data generated will form the basis for dialogue with the British Standards Institution (BSI) to create specific requirements for COB components within the BS 9450 series.

COB technology permits the rapid modification of existing product designs, particularly where space is at a premium.

Other key benefits include the elimination of a level of packaging (which saves space, weight and cost), improved high frequency performance with a reduced number and length of interconnections, and improved thermal dissipation from bare devices compared to plastic packaged devices if thermal vias are incorporated into the board. Flexible circuits can be folded to optimise space utilisation and lead-free assembly can be used for temperature- sensitive components.

Although these benefits have been widely recognised, the performance of COB assemblies in harsh environments has been a cause for concern. MCE is aiming to establish an agreed benchmark for COB assembly which will alleviate these concerns by determining the reliability of representative test circuits and through extensive dialogue with BSI and end-users.

The company's research supports its recent development of a new, high- performance, capability for COB assembly of printed and flexi-rigid circuit boards. MCE's Newmarket facility has been developed in association with Prism Electronics Ltd and is backed up with a comprehensive reliability programme to give end-users higher confidence in the use of these components in demanding applications.

MCE has invested in automatic aluminium wire bonding and glob-top encapsulation equipment. Prism Electronics (www.prism-electronics.com) has sourced the circuit boards and provided surface mount component assembly capability to support this initiative. It has also developed procedures to ensure that the circuits supplied are suitable for COB assembly.

MCE – part of Smiths Aerospace Electronics Systems – is a leading supplier of high reliability electronics for aerospace, defence, industrial, telecommunications, computer and medical applications. MCE specialises in the design and manufacture of customised electronic modules.

The BS 9000 system, including BS 9450, is probably the world's most longstanding scheme for the certification of electronic components, and continues to be meaningful to the high reliability equipment industry. BSI Product Services can offer certification for this type of component under both the original BS 9000 regime or through the global IECQ scheme. Information is given at www.iecq-cecc.co.uk

BSI Product Services offers testing and certification services to help industry develop new and better products, making sure current and future standards and regulations are met. More information can be found at www.bsi-productservices.com

This programme is just one example of the way that MCE is responding to meet the needs of its end customers. Other programmes are in progress to transfer traditional hybrid technologies onto different substrate materials, extending the frequency and power handling characteristics of hybrid microcircuits

Details from MCE Newmarket, Tel.: 44 (0) 1 638 663 381; E-mail sales@mcenkt.co.uk, web site www.micro-circuit.com.