Browse Prior Art Database

Contact Printer Frame for Double-Sided Lithography On 70 mm TAB

IP.com Disclosure Number: IPCOM000119670D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 4 page(s) / 131K

Publishing Venue

IBM

Related People

Grebe, KR: AUTHOR [+3]

Abstract

This apparatus makes it possible to do aligned exposures of photoresist on two sides of a membrane (KAPTON*) recessed and surrounded by a support frame.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Contact Printer Frame for Double-Sided Lithography On 70 mm TAB

      This apparatus makes it possible to do aligned exposures
of photoresist on two sides of a membrane (KAPTON*) recessed and
surrounded by a support frame.

      Present day requirements for high-end wiring and packaging
requires metalization and wiring channel fabrication on two sides of
a support dielectric membrane.

      This membrane is presently KAPTON and varies in thickness from
fractions of a mil to several mils.  Since this membrane can be very
flimsy, it requires a support frame to keep it in place and under
tension during the various process steps.

      The support consists of a 70 mm x 70 mm sprocketed (optional)
frame, having a 50 mm x 50 mm window in its center.  The frame is
made of 5-mil-thick KAPTON, to match the CTE of the 1 mil KAPTON
dielectric membrane.

      A support frame of this type is laminated to each side of the
KAPTON dielectric for purposes of balancing the stress forces and
increase the rigidity of the frame. Bonding agent for the frames to
the dielectric can be epoxy, polyimide or any other cementing agent
compatible or necessary to survive the various processes.

      Wiring is fabricated on the KAPTON dielectric by various means,
such as additive or subtractive processes. Such wiring requires very
accurate alignment from one side to the other, in order to match the
impedances and other electrical properties, as well as to make
interconnections by use of vias.

      Fabrication of two-sided wiring for high-end packaging requires
photolithographic printing of high quality and accurate alignment,
which are not attainable under normal printing methods. Due to the
thickness of the support frame, standard contact printing is negated
and only projection printing would allow accurate fine line
delineation. Equipment of this type is presently not available and
would be extremely expensive.

      This contact printing frame allows accurate aligned contact
printing onto recessed surfaces, as well as printing or exposing on
both sides of the film or substrate.  The fixture consists of two
frames (Figs. 1A and 1B) that are aligned to each other by pins (C)
and bushings (D), which allows to separate and regroup to exact
location.  Each frame (A and B) holds a plate (E). The plate (E) has
a recess in which a glass mask (F) is permanently fixed by means of
glue or epoxy.  The glass mask (F) is cut to 45 mm x 45 mm
to fit into the Tab frame opening and allow for X - Y movement and
fit into the plate (E) with its printing or emul...