Moulded interconnect devices

Whereas traditional PCB are flat or flexible, injection moulded three-dimensional versions, also known as moulded interconnect devices (MID) have been developed which combine a circnit board, enclosnre, connector and cable into one unit. Traditional techniques of installing the electronic circnitry on to the MID have included laser imaging, two-component moulding or hot foil stamping. 

As consumer products become smaller and offer more services to the user, one frequent consequence is that they contain increasing numbers of physically smaller components. A typical example of this trend is the hearing aid where the emphasis is on providing a more powerful and efficient device which will improve the wearer s quality of life. The Acuris P hearing aid from Siemens incorporates a moulded interconnect device (MID) made from Ticona s Vectra E820i LDS liquid crystal polymer (TCP). This novel plastic permits complex, fine-line circuit patterns to be laser-etched and then plated. The MID itself, whose function is to connect the microphone module to other electronic components in the unit, is approximately 3 mm wide and 25 mm long. 

Rychwalski, J.E. (1990) New developments and commercial applications in moulded interconnect device technology. Paper presented at the 5th Printed Circuit World Convention, Glasgow, 12-15 June 1990. 

Recent developments from GE Advanced Materials include ILLUMINEX display film and the X Gen product range where X stands for extreme. These products are said to push the boundaries in terms of aesthetics, high/low temperature performance, weather and chemical resistance, mechanical and electrical tolerance. For example the XHT grade of Ultem polyetherimide has been described by GE as the highest heat, injection mouldable amorphous resin available today. Appfications include flexible PCB able to withstand the new high soldering temperatures and moulded electrical interconnect devices. 

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