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Pellicles for Large Masks

IP.com Disclosure Number: IPCOM000109410D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 33K

Publishing Venue

IBM

Related People

Doany, F: AUTHOR [+2]

Abstract

A pellicle is generally used, supported some distance above a mask, to keep dust off the mask and off the part when an exposure for photolithography is made. The dust is then out of focus. For large parts, such as the 30 cm and larger active matrix thin film transistor (TFT) display panels, this mask is very expensive.

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Pellicles for Large Masks

       A pellicle is generally used, supported some distance
above a mask, to keep dust off the mask and off the part when an
exposure for photolithography is made.  The dust is then out of
focus.  For large parts, such as the 30 cm and larger active matrix
thin film transistor (TFT) display panels, this mask is very
expensive.

      A method of parallel construction of polyimide packages has
recently been disclosed wherein the polyimide film is spun on, doctor
bladed on, or cast on a quartz plate, and after the metal film has
been applied and patterned, the polyimide is irradiated with a high
power excimer laser from the quartz side to separate the film from
the quartz with no distortion.  This film can then be joined with
another substrate for construction of a package.

      A similar mechanism that can be used to make a zero stress
release layer for a pellicle is disclosed here.  A large sheet of
quartz is coated with a thin layer (less than 500 Ao) of polyimide.
Then, another polymer with appropriate characteristics is spread
thinly on the polyimide, and a frame, open in the center, is attached
to the polymer.  The polymer film is separated from the quartz by
irradiating the polyimide film though the quartz.  The polymer film
can then be lifted with no stress and used as a pellicle.