Solution to plasma-etching puzzle could mean more powerful microchips
Research conducted by PPPL in collaboration with the University of Alberta provides a key step toward the development of ever-more powerful computer chips. The researchers discovered the physics behind a mysterious process that gives chipmakers unprecedented control of a recent plasma-based technique for etching transistors on integrated circuits, or chips. This discovery could help to maintain Moore’s Law, which observes that the number of transistors on integrated circuits doubles nearly every two years
The recent technique utilizes electron beams to reach and harden the surface of the masks that are used for printing microchip circuits. More importantly, the beam creates a population of “suprathermal” electrons that produce the plasma chemistry necessary to protect the mask. The energy of these electrons is greater than simple thermal heating could produce — hence the name “suprathermal.” But how the beam electrons transform themselves into this suprathermal population has been a puzzle.
The PPPL and University of Alberta researchers used a computer simulation to solve the puzzle. The simulation revealed that the electron beam generates intense plasma waves that move through the plasma like ripples in water. And these waves lead to the generation of the crucial suprathermal electrons.
This discovery could bring still-greater control of the plasma-surface interactions and further increase the number of transistors on integrated circuits. Insights from both numerical simulations and experiments related to beam-plasma instabilities thus portend the development of new plasma sources and the increasingly advanced chips that they fabricate.