Lithography

About: Lithography is a research topic. Over the lifetime, 23507 publications have been published within this topic receiving 348321 citations.

High aspect pattern fabrication by nano imprint lithography using fine diamond mold

Abstract: Nano imprint lithography is an attractive fine lithographic method to obtain nano patterns by using low cost process and materials., Various applications have been demonstrated to utilize this fine method. One of the advantages of nano imprint lithography is that a wet development process is not required, which sometimes causes sticking errors by surface tension during wet development process. On the other hand, there is no fear of such defects by imprint lithography because a resist is mechanically deformed and released. We have demonstrated high aspect ratio pattern fabrication as high as 6.0 with 200nm in line width. But the mold is fabricated using thin Si substrate and anisotropic wet chemical etching, which cannot fabricate voluntary patterns by crystalline axis dependence.

Ion Beam Lithography

Abstract: Apparatus and method for projection ion beam lithography are described which allow formation of low distortion, large field, reduced images of a mask pattern at a wafer plane using an optical column of practical size. The column shown is comprised of an accelerating Einzel lens followed by a gap lens, with numerous cooperating features. By coordinated selection of the parameters of the optical column, lens distortion and chromatic blurring are simultaneously minimized. Real time measurement of the position of the image field with respect to the existing pattern on the wafer is employed before and during the time of exposure of the new field and means are provided to match the new field to the existing pattern even when the latter has been distorted by processing. A metrology system enables convenient calibration and adjustment of the apparatus.

Electron beam and scanning probe lithography: A comparison

Abstract: Electron beam lithography (EBL) and scanning probe lithography (SPL) are electron exposure techniques capable of high resolution patterning of organic resists. This article compares the exposure properties of these two systems. We consider the resist sensitivity to EBL and SPL electrons, exposure tolerances, patterning linearity, and proximity effects. It is possible to print sub-50 nm features using both systems, but SPL has a wider exposure latitude at these small feature sizes. SPL requires a significantly higher incident electron dose for exposure than does EBL. In EBL, lithography control is most limited by proximity effects which arise from backscattered electrons whose range is considerably larger than the forward scattering range in the resist film. As a result, the exposed feature dimension depends strongly on the local feature density and size, leading to unacceptable linewidth variations across a wafer. These limitations are alleviated in the case of SPL exposures. We demonstrate improved linearity and reduced proximity effects with SPL. We have patterned 200 nm pitch grids with SPL where all individual features are resolved. The linewidth of features in these grids is the same as the width of an isolated line at the same dose. Finally, we suggest that the SPL exposure mechanism may be different than that for EBL.

Composition for forming base film for lithography and method for forming multilayer resist pattern

Abstract: A composition for forming an underlayer film for lithography for imparting excellent optical characteristics and etching resistance to an underlayer film for lithography, an underlayer film being formed of the composition and having a high refractive index (n) and a low extinction coefficient (k), being transparent, having high etching resistance, containing a significantly small amount of a sublimable component, and a method for forming a pattern using the underlayer film are provided. The composition for forming an underlayer film contains a naphthalene formaldehyde polymer having a specific unit obtained by reacting naphthalene and/or alkylnaphthalene with formaldehyde, and an organic solvent.

A proposal for maskless, zone‐plate‐array nanolithography

Abstract: We propose a novel form of x‐ray projection lithography that: (1) requires no mask, and hence can be considered an x‐ray pattern generator; (2) is, in principle, capable of reaching the limits of the lithographic process. The new scheme utilizes an array of Fresnel zone plates, and matrix‐addressed micromechanical shutters to turn individual x‐ray beamlets on or off in response to commands from a control computer. Zone plate resolution is approximately equal to the minimum zone width, which can approach 10 nm. Zone plates are narrow‐band lensing elements: For a diffraction limited focus, the source bandwidth Δλ/λ should be less than or equal to the reciprocal of the number of zones N. An undulator having Nu magnetic sections emits collimated radiation in a bandwidth Δλ/λ=1/Nu. Nu is usually in the range 35–100. We present a system design based on 25 nm lithographic resolution using λ=4.5 nm. For N=100 the zone‐plate diameter is 10 μm. Each zone plate of the array would be responsible only for exposure wit...