Characterisation of chip-on-board (COB) encapsulate epoxies used in the printed circuit board assembly (PCBA) industry using variable frequency microwave (VFM) facilities

Ku, H. S. and Siu, F. and Mok, P. L. and Siores, E. and Ball, J. A. R. (2002) Characterisation of chip-on-board (COB) encapsulate epoxies used in the printed circuit board assembly (PCBA) industry using variable frequency microwave (VFM) facilities. In: 2nd World Engineering Congress (WEC 2002), 22-25 Jul 2002, Sarawak, Malaysia.

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In the printed circuit board assembly (PCBA) industry, integrated circuit (IC) dies are attached onto the printed circuit board (PCB) with epoxy. The die pads are first connected to the PCB tracks with gold or aluminium wires, utilising an ultrasonic wire-bonding machine. The dies are then coated with thermally cured epoxy. The chip-on-board (COB) is finally placed in an electrical oven for baking at certain temperature for a certain period of time, depending upon the type of epoxy used, until the adhesive is completely cured. The baking process using an electrical oven is time-consuming and costly. An alternative way of curing the epoxy is desirable searched. A variable frequency microwave (VFM) source is identified as the possible solution. The first step in curing the epoxy using VFM heating is to find out the best frequency to process the materials in microwaves and this is termed as 'characterisation' of the epoxy by the VFM oven manufacturers. Two VFM facilities were employed to perform the characterisation. One is in the frequency range of 2–8 GHz and the other is in the frequency range of 6.5–18 GHz. By using these two facilities, the best frequency range to process an epoxy by VFM can be identified. Two high quality and commonly epoxy resins, Uniset adhesive and Hysol encapsulant were chosen for consideration. The two resins were then characterised by VFM facilities. From the graphs of the characterisation, a better resin of the two can be identified.

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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2002 WEC. No evidence of copyright restrictions.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 11 Oct 2007 01:06
Last Modified: 12 Nov 2013 05:40
Uncontrolled Keywords: printed circuit board assembly industry; chip-on-board; encapsulate epoxies; variable frequency microwave facilities
Fields of Research : 09 Engineering > 0912 Materials Engineering > 091299 Materials Engineering not elsewhere classified
09 Engineering > 0910 Manufacturing Engineering > 091099 Manufacturing Engineering not elsewhere classified
10 Technology > 1006 Computer Hardware > 100606 Processor Architectures
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering

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