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Use of Fluorescent Material in the Panel Substrate to Aid Accurate Placement of Tape Automated Bonding Devices (TAB)

IP.com Disclosure Number: IPCOM000037580D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hebert, T: AUTHOR [+2]

Abstract

A method to accurately locate the fiducial marks on the printed circuit panel to aid accurate placement of Tape Automated Bonding devices is described.

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This is the abbreviated version, containing approximately 100% of the total text.

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Use of Fluorescent Material in the Panel Substrate to Aid Accurate Placement of Tape Automated Bonding Devices (TAB)

A method to accurately locate the fiducial marks on the printed circuit panel to aid accurate placement of Tape Automated Bonding devices is described.

Fiducial marks are generally copper dots at specified locations on the substrate and are used by the placement device as reference points for accurate placement of components on their respective footprints. The fiducials should be bright enough to be optically located by the placement tool. Since the TAB device is placed and attached last following the vapor phase and wave solder operation the copper fiducials are either oxidized or covered with solder and become unusable as locators.

A fluorescent dye is incorporated into the substrate polymer matrix, namely, the epoxy-glass under the copper. A beam of ultraviolet light is directed onto the fiducial on the panel. Due to the fluorescent nature of the dye a bright halo will be generated around the copper fiducial mark. This bright outline of the fiducial can then be picked up by the camera and used as the locator mark. This bright fluorescent glow is independent of the surface condition of the fiducial mark.

The method described eliminates the cleaning, and/or protection of the fiducial marking prior to placement of the TAB.

Disclosed anonymously.

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