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Triple Layer System for High Resolution Microlithography

IP.com Disclosure Number: IPCOM000045704D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 34K

Publishing Venue

IBM

Related People

Bassous, E: AUTHOR [+4]

Abstract

A high-resolution microlithographic process is described which is particularly useful for patterning sub-micron features over sharp steps on a surface.

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Triple Layer System for High Resolution Microlithography

A high-resolution microlithographic process is described which is particularly useful for patterning sub-micron features over sharp steps on a surface.

Referring to Fig. 1A, the surface of substrate 10 is first coated with a planarizing organic layer 12, e.g., polymethlymethacrylate (PMMA), followed by a thin amorphous silicon film 14, and finally a thin electron-sensitive or photon- sensitive film 16 for imaging purposes, e.g., Shipley AZ 1350J. The pattern is defined in the top layer by E-beam lithography (Fig. 1B). and the pattern is then replicated in the silicon film and the PMMA film by dry etching such as reactive ion etching, as shown in Fig. 1C.

Although other multilayer resist systems have been proposed to accomplish the same purpose 11-71, the described triple-layer method offers distinct advantages due to the unique characteristics of the amorphous Si film, and the freedom it allows in the selection of the film materials for imaging and planarization purposes. The main attributes of this method are:

1. Amorphous silicon films are readily deposited by decomposing

silane gas in a plasma. Deposition can be made on a

substrate at room temperature or at elevated temperature.

2. Thin films are smooth, non-granular, and transparent, and act

as excellent barriers in preventing mixing between different

resist layers.

3. The electrical conductivity can be increased by the addition

of dopants during deposition in order to minimize electron

scattering during E-beam writing.

4. Plasma etching of silicon, and organic resis...