Fabrication and performance of nanoscale ultra-smooth programmed defects for EUV Lithography

We have developed processes for producing ultra-smooth nanoscale programmed substrate defects that have applications in areas such as thin film growth, EUV lithography, and defect inspection. Particle, line, pit, and scratch defects on the substrates between 40 and 140 nm wide 50 to 90 nm high have been successfully produced using e-beam lithograpy and plasma etching in both Silicon and Hydrosilsequioxane films. These programmed defect substrates have several advantages over those produced previously using gold nanoparticles or polystyrene latex spheres--most notably, the ability to precisely locate features and produce recessed as well as bump type features in ultra-smooth films. These programmed defects were used to develop techniques for film defect mitigation and results are discussed

A Silicon-Based, Sequential Coat-and-Etch Process to Fabricate Nearly Perfect Substrate Surfaces

For many thin-film applications substrate imperfections such as particles, pits, scratches, and general roughness, can nucleate film defects which can severely detract from the coating's performance. Previously we developed a coat-and-etch process, termed the ion beam thin film planarization process, to planarize substrate particles up to {approx} 70 nm in diameter. The process relied on normal incidence etching; however, such a process induces defects nucleated by substrate pits to grow much larger. We have since developed a coat-and-etch process to planarize {approx}70 nm deep by 70 nm wide substrate pits; it relies on etching at an off-normal incidence angle, i.e., an angle of {approx} 70{sup o} from the substrate normal. However, a disadvantage of this pit smoothing process is that it induces defects nucleated by substrate particles to grow larger. Combining elements from both processes we have been able to develop a silicon-based, coat-and-etch process to successfully planarize {approx}70 nm substrate particles and pits simultaneously to at or below 1 nm in height; this value is important for applications such as extreme ultraviolet lithography (EUVL) masks. The coat-and-etch process has an added ability to significantly reduce high-spatial frequency roughness, rendering a nearly perfect substrate surface

Reflective coating for near infrared immersion gratings

Abstract not provide

<title>Experimental investigation of beryllium-based multilayer coatings for extreme ultraviolet lithography</title>

The performance of beryllium-based multilayer coatings designed to reflect light of wavelengths near 11 nm, at normal incidence, is presented. These multilayer coatings are of special interest for extreme ultraviolet lithography (EUVL). The beryllium-based multilayers investigated were Mo/Be, Ru/Be and a new material combination Mo,CiBe. The highest reflectivity achieved so far is 70% at 11.3 mn with 70 bilayers of Mo/Be. However, even though high reflectivity is very important, there are other parameters to satisfy the requirements for an EUVL production tool. Multilayer stress, thermal stability, radiation stability and long term reflectance stability are of equal or greater importance. An experimental characterization of several coatings was carried out to determine the reflectivity, stress, microstructure, and long term stability of these coatings. Theoretically calculated reflectivities are compared with experimental results for different material pairs; differences between experimental and theoretical reflectivities and bandwidths are addressed. Keywords: Extreme ultraviolet (EUV) lithography, reflective coatings, multilayer deposition, beryllium