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.

Reduction of proximity effect in electron beam lithography by deposition of a thin film of silicon dioxide

Abstract: We present a simple strategy to reduce the writing time of electron beam lithography (EBL) by using a highly sensitive Shipley’s UV-5 resist while reducing proximity effects by depositing a thin film of silicon dioxide (SiO2) on silicon substrate. It was found that a simple insertion of a thin SiO2 film greatly reduced proximity effects, thereby providing enhanced resolution and better pattern fidelity. To support this conclusion, the bottom line width and sidewall slope of the developed pattern were analyzed for each substrate with different film thickness.

Registration mark detection in electron beam proximity printing

Abstract: Electron beam proximity printing is a lithography method for high throughput exposure of repetitive patterns with submicron structures. An electron beam shadow projects the pattern contained in a transmission mask onto the wafer. Pattern registration in this projection printer is achieved by using the electron beam current absorbed in the wafer. Two registration steps are employed: one for wafer (or global) align, the other for chip (or local) align. The achieved registration accuracy is better than 0.1 μm using 10 keV electrons and 1.1 μm thick PMMA on the wafer registration marks.

Computation method of proximity effect, dangerous point detector, and program

Abstract: PROBLEM TO BE SOLVED: To provide the computation method of the proximity effect which can reduce the time and labor required for detecting dangerous points in a pattern to be transferred onto a thin-film layer in EB (electron beam) exposure. SOLUTION: The computation method of the proximity effect includes a step (S11) wherein a photolithographic layer pattern to be transferred onto the thin-film layer and an underlying layer pattern to be transferred onto an underlying layer of the thin-film layer in EB exposure are each divided into a plurality of unit areas; a step (S12) of setting representative figures corresponding to the photolithographic layer pattern and the underlaying layer pattern, respectively, for each unit area; and a step (S13) of calculating the influence by the proximity effect in an arbitrary area of the photolithographic layer pattern based on the representative figures. COPYRIGHT: (C)2007,JPO&INPIT

Drawing method using charged particle beam

Abstract: PROBLEM TO BE SOLVED: To realize a drawing method which uses a charged particle beam and is capable of making a correction for a proximity effect and furthermore coping with a micronization of a pattern to draw SOLUTION: A correcting time for a shot time of the electron beam is obtained on a line width correction volume (loading correction volume) obtained through a conversion formula of the ratio of a pattern area rate to the line width correction volume previously obtained on the basis of the calculated area of the pattern Moreover, a relation between the line width correction volume and the correcting time for the shot time of the electron beam has be previously obtained The obtained correction time is obtained for each unit by an operation and pseudo-pattern data large enough to give an enough amount of accumulated scattering electrons for correcting a change of the line width caused by a loading effect are formed The pseudo-pattern data are added to actual pattern data, and the pseudo-pattern is also used for calculating a correction for a proximity effect, and in fact, a specific command is annexed to the pseudo-pattern data so as not to be shot COPYRIGHT: (C)2004,JPO

Design and fabrication of low noise high diffraction efficiency diffractive optical elements

Abstract: We demonstrate a method to fabricate high quality and environmentally rugged monolithic Diffractive Optical Elements (DOEs). Analog direct-write e-beam lithography was used to produce analog resist profiles that were transferred into their substrates using Chemically Assisted Ion Beam Etching (CAIBE) in one single etching step. The Point Spread Function of the e-beam during exposure caused by forward electron scattering in the resist and back scattering from the substrate was determined by measuring the exposure of a step function. An iterative method that makes use of the point spread function was developed to adjust the electron exposure file and compensate for the proximity effect caused by electron scattering. Slope dependent etch rates that occur during the microstructure transfer process were characterized and also compensated for by exposure file adjustment. Finally, the DOE was divided into regions with different periodicity ranges. For each periodicity range the range of clock speed for the exposure is set to achieve even and accurate feature depth in the final element. Many DOEs have been fabricated by this technique including a Fresnel lens of 32 phase levels. DOEs fabricated using this technique, can be used as high quality masters for a following replication process based on molding, casting etc. Moreover comparing with conventional binary optics fabrication methods, which require multiple exposure and processing steps for master generation, our approach requires only a single lithography and etching step. Therefore the fabrication method presented in this paper will not only yield high quality masters, but will also result in a general cost reduction and reduce the turnaround time between design and replication.