Considering the Use of Ultraviolet Light Sources to Produce Advanced ICs

April 25, 2020 by Luke James

Scientists at Tokyo Institute of Technology have recently developed an extremely low-density tin ‘bubble’ which makes extreme ultraviolet reliable and cheap to generate.

The Tokyo Tech team has achieved this by creating tin thin-film spheres using a polymer electrolyte “soap bubble” made from polyelectrolyte—which are extremely stable and suitable for mass production—as a template and irradiating it with a laser. 

Once the spheres were irradiated, the research team was able to confirm that extreme ultraviolet (EUV) rays of 13.5nm were emitted, the same as metallic tin. It is thought by the research team that their novel technology could pave the way for various applications in electronics like advanced semiconductors, as a reliable means of EUV light generation. 


A graphic showing how nanosized-wall tin bubbles can generate extreme ultraviolet light.

A graphical depiction of how the nanotized-wall tin bubbles were used in the study to generate EUV light. Image credited to Keiji Nagai


The Use of EUV in Advanced ICs 

High-intensity lasers have been used to generate EUV light in the past, however, it has proven challenging for these lasers to maintain control of a target density that can produce light in the EUV range. 

Working with colleagues from University College Dublin, the Tokyo Tech team set out to find laser targets that could be used to generate EUV light while remaining efficient, scalable, and low in cost. Their tin-coated microcapsule ‘bubble’ technology is a low-density structure that can be highly controlled. It consists of polymer electrolytes which are then coated in tin nanoparticles. 


Suitability for Manufacturing Semiconductors

To put the bubble to the test, the research team irradiated it using a neodymium-YAG laser. This resulted in the generation of EUV light in the 13.5nm range, with the team also finding that the structure was compatible with the conventional EUV light sources that are used to manufacture semiconductors

“Overcoming the limitations of liquid tin dynamics can be very advantageous in generating EUV light,” said professor Keiji Nagai. “Well-defined, low-density tin targets can support a wide range of materials including their shape, pore size, and density.”