Fabrication of high resolution x-ray masks using diamond membrane for second generation x-ray lithography

Abstract

Second generation x-ray lithography (PXL-II) has been proposed to extend proximity x-ray lithography to the 50 nm generation and beyond while keeping a high throughput. Diamond membrane, which enables high power and shorter x-ray irradiation, is a key material for PXL-II. In this article, we describe the fabrication of ultrafine patterns of W–Ti absorber on thinned diamond membranes. By optimization of the etching conditions, about 30 nm W–Ti patterns with aspect ratios of about 10 were successfully fabricated. The dependence of pattern edge roughness of the absorber on the surface roughness of the diamond has also been investigated, and it has been shown that 3 nm rms roughness was enough to obtain the pattern quality equivalent to that on a SiC membrane. For narrower gap exposure with x-ray masks with thick diamond membrane in PXL-II, the flatness of the mask top surface has been studied, and we developed x-ray masks with a flatness of less than 1 μm by modifying the support ring geometry.

Temperature Dependence of Formation of Nanorods and Dots of Iodine Compounds on an H-Terminated Si(111) Surface in a Concentrated HI Solution

“…Formation of regulated nanostructures on semiconductor surfaces constitutes the basis of future hugely integrated and intelligent devices. 1,2 Conventional photolithography has been used for microfabrication for a long time, but this method has the severe limit in that the control size is limited to about 50 nm 3 . Recently, atomicscale fabrication by use of surface probe microscopes such as scanning tunneling microscopy (STM) and scanning near-field optical microscopy (SNOM) 4,5 has been attracting much attention as a powerful method for nanostructuring, but this method has also a severe limit in that it is not adaptable to mass production, which is eventually necessary for practical application.…”

Theoretical Analysis on Mechanical Deformation of Membrane-Based Photomask Blanks

“…2. 28) Figure 14 shows the relation between the OPD 4 and the side length of the square back-etch window as a parameter of the membrane stress for a support plate with a circular hole of 82 mm in diameter, which has generally been used in the X-ray lithography. 29,30) The OPD 4 have a peak around 25-30 mm of the back-etch window and the peak value is 3 m even for the smaller membrane stress of 100 MPa.…”

Highly Ordered Chevron-Shaped Arrays of Continuous Copper Nano-Dot Lines Formed by Electroless Deposition on Hydrogen-Terminated Si(111) Surfaces

“…Nanostructuring at semiconductor surfaces, which constitutes the basis of future hugely integrated and intelligent devices, − has been attracting keen attention in the field of semiconductor sciences and technologies. Much effort has been done to find and develop new structuring techniques that have a fabrication size significantly smaller than the limit of conventional photolithography. − Recently, atomic-scale fabrication by use of surface probe microscopes such as scanning tunneling microscopes and scanning near-field optical microscopes , has been attracting strong attention as a powerful technique for designed and well-controlled nanostructuring, but this technique has a severe limit in that it is not adaptable to mass production, which is inevitably necessary for practical application.…”