Lithography Systems

Electron-beam lithography systems are used in the creation of integrated circuits - the electron beam is used to directly expose resist on the surface of the silicon wafer, and must therefore have it's position controlled to within a few 10s of nanometers.

We were responsible, working with Softsim Limited, for designing the electronics of an 'add-on' kit, used to convert a scanning electron microscope into a lithography system.

Design process - from specification to production

• Schematic layout of and system design of 19" rack mounted assembly.
• Liason with pcb layout engineer, responsibility for component placement and layout verification.
• Responsibility for purchase and kitting of components, and interface to assembly house.
• Testing of boards and implementing any design changes required.
• Firmware design & coding.
• Responsibility for hardware and software interface to 3rd party elements of the system.
• Responsibility for installation at the end-customer site, system final verification, and customer training.

Design Elements

• Optically isolated USB communications.
• Precise ( sub micron ) control of a mechanical stage via piezo-electric motor control Laser interferometry system with measurement resolution of 2.5nm.
• Optical absolute positional measurement, to provide a reference for the interferometry.
• Boards to operate inside vacuum chamber.
• High resolution analogue control of electron-beam positioning, with real-time feedback and correction.
• Acquisition of high resolution video signals for system calibration.
• Firmware, using Altera CPLDs, and software, using Analog Devices DSPs,  for real time system control.