Browse Prior Art Database

IMPROVED CIRCUIT FLEXIBILITY USING LASER THINNING

IP.com Disclosure Number: IPCOM000008903D
Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2002-Jul-23
Document File: 1 page(s) / 67K

Publishing Venue

Motorola

Related People

Robert Carson: AUTHOR [+4]

Abstract

Flexible circuits are intended for use in applica- tions where space is at a premium and bending is required. Copper on the outer surface of a bend experience considerable tension (Figure I) and can crack when the distance to the bending neutral axis is too great (i.e. the substrate is too thick).

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0 M MO-LA

Technical Developments

IMPROVED CIRCUIT FLEXIBILITY

USING LASER THINNING

by Robert Carson, Rick Mangold, Chris Becher and Oyi Neiconi

  Flexible circuits are intended for use in applica- To provide greater flexibility, laser thinning the tions where space is at a premium and bending is back surface of a single layer flexible circuit reduces required. Copper on the outer surface of a bend the copper distance to the neutral axis (Figure 2). experience considerable tension (Figure I) and can
crack when the distance to the bending neutral axis

The laser thinned circuit would be superior to the original circuit because! it could tolerate smaller

is too great (i.e. the substrate is too thick). bending radii and have a rnatural" tendency to bend in the thinned regions.

Flexible Circuit Bending Before Processing ~

Copper layer

eutrel Axis for Flexible Circuit

Fig. 1 Schematic representation of a 180" bend created in a single sided flexible circuit where copper experiences tensile stresses. ~

Flexible Circuit Bending After Processing ~

Copper layer

Neutral Axis for thinned zone \ Laser Thinned "y

  Fig. 2 Schematic representation of a 180" bend created in a single sided flexible circuit following laser thinning. Note that in the bend region, thinning has reduced the copper's distance to the substrate neutral axis.

12 JanuaIy 1999

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