Glass is key to super-fast ‘3D’ circuit boards

A new generation of super-fast ‘3D’ glass electronic circuit board is being developed by Loughborough University.

Glass enables direct microchip contact with circuits and the use of optical devices. Historically plastic printed circuit boards have been used to connect electronic devices but they will be unable to link the tiny chips of the future.

Dr David Hutt, the project’s principal investigator, expects the new technology to aid the process of miniaturisation, and remove obstacles to increasing computing performance that lie beyond microchip design. ‘The main advantage of glass is that it provides the fine features needed for direct contact, as well as being a material through which light signals can be sent. No longer will chips need a plastic casing and long solder connections.’

The advantages of direct connection are two-fold. Data transfer from circuit to micro-processor is faster and the lack of any plastic-encasing silicon means less PCB area is used.

The team will be using lasers to create tracks across the surface of the glass, which are then inlaid with copper to provide the very fine connections needed.But components will not be placed on one side of the glass circuit board only. The lasers will also be used to create ‘vias’, or vertical tracks, that go through the glass to connect components on each side.

These tracks will carry optical signals between components. Hutt explained that the glass technology could also be an alternative to multiplexers, which are used to turn optical-fibre laser light into electrical signals: ‘With glass we can connect the circuit board directly to the optical fibre, speeding up the link between the computer and its network.’

The project is a joint venture with the Rutherford-Appleton Laboratory and private investors, and supported by £60,000 from the Engineering and Physical Sciences and Research Council.

The ‘3D’ idea behind the glass circuit board design is similar in concept to memory chips that will be launched this year by California-based MatrixSemiconductor.