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Browse Prior Art Database

A Solder Rivet

IP.com Disclosure Number: IPCOM000109151D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 61K

Publishing Venue

IBM

Related People

Coteus, PW: AUTHOR [+3]

Abstract

Tape Automated Bonding (TAB) packages are often used in the electronics industry. The more recent packages contain metal wiring, i.e., copper, on both sides of a polyimide dielectric. The packages with the finest lines and spaces use additive plated copper and chemically milled vias in the dielectric. More recently this same technology has been used to make thin, flexible circuit cards. Both of these technologies have the feature that they are connected with solder to rigid substrates, for example, a fiberglass-epoxy based circuit card. Although these new flexible structures offer superior electrical, size, and mass advantages over the pin and socket packages that they replace, they are not nearly as mechanically robust.

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This is the abbreviated version, containing approximately 71% of the total text.

A Solder Rivet

      Tape Automated Bonding (TAB) packages are often used in the
electronics industry.  The more recent packages contain metal wiring,
i.e., copper, on both sides of a polyimide dielectric.  The packages
with the finest lines and spaces use additive plated copper and
chemically milled vias in the dielectric.  More recently this same
technology has been used to make thin, flexible circuit cards.  Both
of these technologies have the feature that they are connected with
solder to rigid substrates, for example, a fiberglass-epoxy based
circuit card.  Although these new flexible structures offer superior
electrical, size, and mass advantages over the pin and socket
packages that they replace, they are not nearly as mechanically
robust.  The connections between the flexible packages and the rigid
substrate upon which they are mounted is particularly prone to
mechanical damage.  We show a unique solder rivet which combines an
electrical connection with a mechanically robust structure, to
greatly improve the fragility of this connection.  The construction
of the rivet fits naturally into the construction of the TAB or
flexible circuit card.

      The figure shows a schematic side view of the solder rivet,
connecting a two metal layer flexible circuit with a rigid circuit
card.  The inner diameters of the copper traces on the top and bottom
surfaces of the flex must be carefully chosen.  In this example, the
polyimide is 2 mils (.002 inches) thick,...