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Linewidth Variation in E-Beam Technology

IP.com Disclosure Number: IPCOM000050638D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Gillespie, SJ: AUTHOR

Abstract

This technique provides a controlled, smooth linewidth variation from a single beam using direct write E-beam lithography by employing electron dose control.

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Linewidth Variation in E-Beam Technology

This technique provides a controlled, smooth linewidth variation from a single beam using direct write E-beam lithography by employing electron dose control.

As indicated in the figure, a semiconductor substrate 10 has a layer of silicon dioxide 12 grown thereon with a layer of polysilicon 14 deposited onto silicon dioxide layer 12. A layer of negative electron resist 16 is then deposited on polysilicon layer 14.

To form a variable-width polysilicon line from polysilicon layer 14, an electron beam having a single width is directed into the resist layer 16 along the vertical path 18 of uniform width, indicated by vertical dashed lines and formed as a series of rectangular spots having, e.g., a 4 to 1 length to width ratio. Although the width of the electron beam does not vary as it moves along vertical path 18, the incident dose of electrons is varied so that along segment a of vertical path 18 the beam radiates a constant given amount of electrons, along segments b the beam radiates a constant amount of electrons having twice the dose of the given amount, and along segment c the beam radiates a constant amount of electrons having three times the dose of the given amount. The given amount of electrons may be, e.g., 2.5 micro-Coulombs (MuC), 5 MuC and 7.5 MuC.

After the electrons of varying dose are introduced into the vertical path 18, any appropriate developer may be used to remove the layer of resist 16 from all portions of the surface of the polysilicon layer 14 except those portions of the photoresist layer 16 affected by the beam of electrons. After development, segment a of path 18, into which a dose o...