Bright and clean x-ray source for x-ray based metrology

Abstract

Methods and systems for x-ray based semiconductor metrology utilizing a clean, hard X-ray illumination source are described herein. More specifically, a laser produced plasma light source generates high brightness, hard x-ray illumination having energy in a range of 25,000 to 30,000 electron volts. To achieve high brightness, a highly focused, very short duration laser beam is focused onto a denseXenon target in a liquid or solid state. The interaction of the focused laser pulse with the high density Xenon target ignites a plasma. Radiation from the plasma is collected by collection optics and is directed to a specimen under measurement. The resulting plasma emission is relatively clean because of the use of a non-metallic target material. The plasma chamber is filled with Xenon gas to further protect optical elements from contamination. In some embodiments, evaporated Xenon from the plasma chamber is recycled back to the Xenon target generator.

Description

technical field [0001] The described embodiments relate to x-ray laser generated plasma radiation sources and systems for x-ray metrology and inspection. Background technique [0002] Semiconductor devices, such as logic and memory devices, are typically fabricated by a sequence of processing steps applied to a substrate or wafer. Various features and multiple structural levels of the semiconductor device are formed through these processing steps. For example, photolithography, in particular, is a semiconductor fabrication process that involves creating patterns on semiconductor wafers. Additional examples of semiconductor fabrication processes include, but are not limited to, chemical mechanical polishing, etching, deposition, and ion implantation. Multiple semiconductor devices may be fabricated on a single semiconductor wafer and then separated into individual semiconductor devices. [0003] During the semiconductor manufacturing process, metrology processes are used a...

AI Technical Summary

Problems solved by technology

However, the radiation produced is relatively low energy (92.6 electron volts), which severely limits the utilization of these sources of irradiation in metrology applications

Images