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.

Method of deciding pattern of reticle

Abstract: PROBLEM TO BE SOLVED: To correctly perform the correction for the proximity effect of a reticle even in the case where a space-charge effect becomes a problem, and to make it possible to form the accurate exposed pattern of the reticle on a wafer. SOLUTION: In a method of deciding the pattern of a reticle, if data on an LSI is inputted to a computer in a step S101, the computer splits the data into subfields in a step S102, and data on the patterns in every subfield of the reticle is created from these subfields. Then, a space-charge effect is calculated in consideration of the density of the patterns in every subfield in a step S103. Lastly, the correction for the proximity effect of the reticle is made in consideration of a diffusion of a beam due to the space-charge effect calculated in the said step 103 in a step S104, the forms of the patterns decided in the step S102 within the subfields are changed. In the case where an exposure of the reticle is performed in the patterns subsequent to the change, the reticle is subjected to the proximity effect and a resist is contrived to be exposed to light into the form of the purposed pattern.

Computer aided proximity effect correction system in photolithography

Abstract: Reflected light from step coverage causes fatal pattern defects in photolithography. The resist pattern defects are caused by the extra exposure from the highly reflective stepped substrate, such as breaks in the pattern of the aluminum layer. The problem is significant when the patterns in the different layers are near each other. We named this problem the proximity effect. The specific design rules such as the space between the resist pattern and the steps on the substrate are evaluated by simulation and experiment. Based on the evaluated results, we propose a computer aided proximity effect correction system to verify the pattern layout and eliminate the proximity effect. The effectiveness of the system is confirmed experimentally.

High Voltage Electron Beam Writing for Submicron Design Rule VLSI Fabrications

Abstract: The advantages of high voltage electron beam lithography in submicron VLSI fabrications have been established. By electron beam lithography with 50 kV acceleration voltage, vertically walled PMMA pattern is obtained at a relatively low dose, 50 µC/cm2. This fact, combined with the increase in beam current, brings about the improvement of throughput in 50 kV writing by a factor of 5 over 20 kV writing. Proximity effect is markedly reduced in 50 kV writing. The pattern size variation due to the proximity effect is within 0.05 µm for line patterns ranging from 10 µm to 0.25 µm. Vertically walled PMMA pattern of 0.25 µm space, which is equal in size to the beam spot, is obtained at 50 µC/cm2 in 50 kV writing. In addition, it is shown that radiation damage of MOSFET's due to the 50 keV beam is essentially the same as that due to 20 keV beam.

Aperture for electron beam lithography

Abstract: PURPOSE:To form an aperture for electron beam lithography in which lithography aperture patterns are formed with high precision so that the size of a resist pattern to be drawn can be easily controlled, and to design and manufacture the aperture itself easily at low costs. CONSTITUTION:Electron amount control apertures 16 and 17 of simple rectangular shape are provided, which are arranged away at a predetermined distance from outermost lithography aperture patterns 11 and 15, respectively, and adapted for correcting proximity effect by controlling the amount of electrons passing through an aperture having a width within a resolution limit. The amount of electrons passing through the electron amount control apertures 16, 17 moderately influences the proximity effect to a pattern to be drawn, so that the size of the pattern to be drawn is easily controlled.