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Memory Storage in Positive Electron Beam Resists

IP.com Disclosure Number: IPCOM000079285D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hiraoka, H: AUTHOR

Abstract

A positive electron-beam resist, specifically a polymethylmethacrylate thin film deposited on a conductive material like a copper disk, is used as a memory storage medium. A penetrating high-energy electron beam is used for writing and a low-energy electron beam for readout.

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Memory Storage in Positive Electron Beam Resists

A positive electron-beam resist, specifically a polymethylmethacrylate thin film deposited on a conductive material like a copper disk, is used as a memory storage medium. A penetrating high-energy electron beam is used for writing and a low-energy electron beam for readout.

Once a penetrating high-energy electron beam has scanned a surface of polymethylmethacrylate (PMMA), a low-energy electron beam is partially able to pass through the scanned part of the film. Specifically, a 20 KeV electron beam was used to scan a surface of 2 micron thick PMMA film deposited on a copper disk, with a speed of 10/-5/ Coulomb/cm/2/. Then, an 1 KeV low-energy electron beam became transmitting through the scanned part of the polymer film (17% of the incident beam current with a glancing indicent angle), but does not pass through the unscanned part, where the opposite direction of the current was observed in an electrometer reading due to capacitance building-up across the film. An 1 KeV electron beam can reach only a few hundredths of a micron deep inside of the polymer, while a 20 KeV electron beam can pass through a several micron thick PMMA film. The part of the film scanned by the high-energy electron beam becomes thinner than the surrounding unscanned part. Also, the high-energy electron beam may have left passages through the film through which low-energy electrons can easily travel without much resistance. The main effect of...