In chip manufacture the smallest particles can make a product useless. To prevent this, it is essential to be able to detect particles of around 50 nanometres. TNO has developed a special scanner, the Rapid Nano, which can ascertain the clean operation methods that are applicable, how well they work and how they can be improved so that no contamination escapes unnoticed.
Nanotechnology has enabled the manufacturer of chips with increasingly smaller structures, with the state-of-the-art being the very finest structures of just 22 nanometres. According to Moore's law, the size will continue to fall year after year. The very slightest contamination during the chip manufacture process can be disastrous. The latest standards for semiconductor equipment stipulate that no more than a single particle of 50 nanometres per ten cycles may be added to a 15 x 15 centimetre mask during the production process. If it happens, you certainly want to know about within a couple of hours. Compare it with trying to pick out a tennis ball lying somewhere in an area the size of the Netherlands while flying a jet fighter at full speed overhead. The question is whether there is one tennis ball more today than there was yesterday and, if so, where is it. No object may be overlooked.
TNO has developed a special scanner, the Rapid Nano, a relatively affordable instrument that can fully scan the reflective surface (of EUV masks, for example) in a shielded clean box. The inspection system uses a double darkfield concept, whereby information is recorded by a camera. The data are then saved for offline dataprocessing and evaluation: tracking and tracing. The solution has particular many benefits. Nanometre particles are scanned in the patented clean box at a velocity of 100 cm2 per hour. Moreover, the solution can be customised to the customer's process. The scanner was used successfully during the development of the robot that transported the EUV masks in the first EUV wafersteppers of ASML, and in the manufacture of image sensors.
Over the past decade TNO has been a leading figure in the detection of particles in the EUV domain. With its knowledge of optics, signal processing, vacuum technology and ultraclean operation, TNO continues to create methods that can reliably detect and localise defects. Prevention is better than cure. Instruments like the Rapid Nano can be used during equipment development so that potential problems are highlighted early on. In this way we help companies to produce attractively priced state-of-the-art.