Could new method change the future of semiconductor etching?

1 min read

University of Illinois researchers have developed a new low cost method to carve delicate features onto semiconductor wafers using light, which can be monitored as it happens.

"You can use light to image the topography and you can use light to sculpture the topography," said electrical and computer engineering professor Gabriel Popescu. "It could change the future of semiconductor etching." The team says the technique can monitor a semiconductor's surface as it is etched in real time, with nanometre resolution. It uses a special type of microscope that uses two beams of light to precisely measure topography. The new method is said to be faster, lower in cost, and less noisy than the widely used methods of atomic force microscopy or scanning tunneling microscopy, which cannot monitor etching in progress but only compare before and after measurements. It is also purely optical, so there's no contact with the semiconductor surface and the researchers can monitor the whole wafer at once instead of point by point. As well as monitoring the process, the light catalyses the etching process. Rather than shining light through masks, the method uses a projector to shine a greyscale image onto the sample. This allows the researchers to create complex patterns quickly and easily, and adjust them as needed. "Because our technique is controlled by the computer, it can be dynamic," said electrical and computer engineering professor Lynford Goddard. "So you can start off etching one particular shape, midway through realise that you want to make some change, and then change the projector pattern to get the desired outcome." The researchers say the technology could be applied beyond etching to real time monitoring of other processes. They claim it could help chip manufacturers reduce costs and processing time by ensuring that equipment stays calibrated. To view a video about this new method, click here.