Browse Prior Art Database

Technique for E-Beam Exposure Tool Evaluation

IP.com Disclosure Number: IPCOM000120697D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 31K

Publishing Venue

IBM

Related People

Kaplan, L: AUTHOR

Abstract

Disclosed is a technique for characterizing an electron-beam exposure tool without the necessity for complete fabrication of test pieces. Such test pieces have formerly been necessary in order to make the linewidth and overlay measurements used in establishing tool performance.

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Technique for E-Beam Exposure Tool Evaluation

      Disclosed is a technique for characterizing an electron-beam
exposure tool without the necessity for complete fabrication of test
pieces.  Such test pieces have formerly been necessary in order to
make the linewidth and overlay measurements used in establishing tool
performance.

      It has been discovered that exposed PMMA resist films, when
suitably baked, show a latent image which may be visible to the naked
eye and/or microscopically.  The clarity of the latent image is a
function of the baking temperature and of the rate of cooling after
bake.  Thus, for photomasks of .090" thickness, bake temperatures of
130~C and above may be used.  For .150" thick plates, which cool more
slowly, the required temperature is 10-15 degrees higher.

      In practice, a hotplate or oven is located adjacent to the
exposure tool, along with a suitable measurement tool. The test plate
is exposed, baked (e.g., 5 min. at 140~C) and the latent image is
measured.  Feedback of linewidth and overlay information for tool
correction is very fast, with correspondingly better exposure tool
utilization.

      Disclosed anonymously.