Miniature Plasma Source for In-Situ Scanner Cleaning

TL;DR

This paper introduces a compact plasma source that enhances in-situ scanner cleaning by increasing speed and reducing thermal load through simultaneous hydrogen radical and ion generation, facilitating easier integration.

Contribution

A novel plasma-based cleaning technique that improves speed and reduces thermal impact, with a compact design for flexible scanner integration.

Findings

Significantly improved cleaning speed.

Reduced thermal load on surfaces.

Compact and flexible plasma source design.

Abstract

EUV Lithography is the technology of choice for High-Volume Manufacturing (HVM) of sub-10nm lithography. One of the challenges is to enable in-situ cleaning of functional surfaces such as sensors, fiducials and interferometer mirrors without opening the scanner tool. Thermally created hydrogen radicals have been successfully used for this purpose. These sources have a limited cleaning speed and relatively high thermal load to the surface being cleaned. Here we present an alternative plasma-based technique to simultaneously create hydrogen radicals and hydrogen ions. This results in significantly improved cleaning speed while simultaneously reducing the overall thermal load. As an additional benefit, this plasma source has a minimized and flexible building volume to allow easy integration into various locations in the EUV lithographic scanner.