Proximity effect (electron beam lithography)

About: Proximity effect (electron beam lithography) is a research topic. Over the lifetime, 940 publications have been published within this topic receiving 8508 citations.

Comparative evaluation of positive and negative chemically amplified resist characteristics for 90-nm-node photomask production

Abstract: For the latest photomask fabrication, better critical dimension (CD) control and pattern fidelity to design size are required. According to the latest ITRS roadmap, masks for the 90 nm technology node should have CD uniformity of 6~8nm (3σ). Moreover, CD control is particularly critical for isolated opaque lines, such as those found in gate layers, whose loading is primarily clear field. The high acceleration voltage electron beam (EB) systems that employ variable shaped beams (VSBs) are used for mask writing due to their high throughput. To minimize write time and fogging effects, and to control mean CD and improve CD uniformity for mask production, it is well known that negative tone resists enable better VSB mask writing system performance. In these circumstances, positive and negative tone chemically amplified resists (CARs), FEP171 (Fuji Films) and FEN270 (Fuji-Films), were evaluated empirically for mask making. We investigated and compared resolution, sensitivity, resist profiles, CD variation vs. exposure dose, proximity effect correction (PEC), fogging effect, pattern fidelity, and so on. Furthermore, write tool data volume and throughput, defect trends, and other process parameters on the positive and negative tone resists were evaluated and compared by applying test patterns.

Study of process of HSQ in electron beam lithography

Abstract: As a kind of inorganic negative-tone resist in electron beam lithography, hydrogen silsesquioxane(HSQ) has a high pattern resolution of about 5 nm, but the poor sensitivity limits its extensive application in the field of micro-fabrication. It's very difficult to fabricate the high aspect-ratio dense resist pattern for HSQ because of backscattering electrons and proximity effect. The methods by optimizing process condition are proposed to improve the contrast of graphic structure of HSQ resist and restrain electron beam proximity effect at the same time. On 450nm thick resist layer, HSQ resist pillar array pattern with 5 aspect-ratio under 50kv voltage and HSQ resist mesh pattern structure with 9 aspect-ratio under 100kv voltage can been achieved with optimization of process condition.

Exposing method of electronic beam

Abstract: PURPOSE:To obtain the highly precise drawing of a microscopic pattern by removing the proximity effect using a method wherein the portions of the exposed pattern, having a smaller measurement of the distance to the adjoining pattern than the prescribed measurement, are discriminated and a reduced amount of exposure is exposed on said portions. CONSTITUTION:The portion B1, where the distance l between patterns A and B arranged in close vicinity each other is smaller than the distance l0 to be effected by the proximity effect arising from the reflection and scattering of the electronic beam on the substrate surface, is discriminated. In the case of the patterns A and B1, they are exposed after the amount of exposure per unit area is corrected to a smaller value taking into consideration of the proximity effect. The portion B2 having no proximity effect is exposed with the prescribed amount of exposure. Hence, the narrowing of the pattern interval due to an overexposure caused by the proximity effect is prevented and a highly accurate drawing can be performed.

Electron beam exposure apparatus

Abstract: PROBLEM TO BE SOLVED: To provide an electron beam aligner for correcting the proximity effect in the exposure of electron beams with accuracy and at high speed. SOLUTION: The electron beam aligner comprises an area density map creation means 3 that divides a fixed region irradiated with electron beams by a mesh, obtains the ratio of a pattern area to be applied to the divided region to the area of each divided region, and creates an area density map; and a proximity-effect correction means 2 for correcting the amount of exposure of electron beams, by referring to the area density map. The proximity-effect correction means 2 comprises a product-sum operation means 6 for performing the product-sum operation of two-dimensional array data and an addition means 7 for performing addition operations, stores the two-dimensional array data of the area density of the pattern in a first memory 8a, and performs the product-sum operations and additions for a prescribed number of times for linearly converting, and calculating the two-dimensional array data of the area density as the two-dimensional array data of amount-of-exposure data used for correcting the proximity effect. COPYRIGHT: (C)2007,JPO&INPIT