Browse Prior Art Database

TAB Tape Structure for Area Array TAB

IP.com Disclosure Number: IPCOM000035408D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Kovac, CA: AUTHOR [+3]

Abstract

Disclosed is a novel structure for TAB tape and outer lead bonding which maintains the advantages of the TAB inner lead thermocompression bond, yet allows direct access to the card grid. The disclosure allows outer lead bonding of TAB packages to fan out to the via grid of the printed circuit card using the TAB structure to replicate the method of attaching PGA structures to cards. This method removes the wiring congestion associated with wiring fan out within a printed circuit card by placing the fan out on the TAB package. The result is an improvement in the wireability of large I/O TAB packages. (Image Omitted)

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TAB Tape Structure for Area Array TAB

Disclosed is a novel structure for TAB tape and outer lead bonding which maintains the advantages of the TAB inner lead thermocompression bond, yet allows direct access to the card grid. The disclosure allows outer lead bonding of TAB packages to fan out to the via grid of the printed circuit card using the TAB structure to replicate the method of attaching PGA structures to cards. This method removes the wiring congestion associated with wiring fan out within a printed circuit card by placing the fan out on the TAB package. The result is an improvement in the wireability of large I/O TAB packages.

(Image Omitted)

The TAB tape structure should be made by a semi-additive structure in which metallization is applied to polyimide film, then windows are etched in the polyimide as desired. Rectangular windows should be etched perpendicular to the perimeter of the tape frame, such that the openings extend over the row of card pads to be bonded to. Metallization, which is present before etching of the polyimide, should have the form shown in Figs. 1A or 1C. Formation of the outer lead bond area can be done by laser ball forming, with the subsequent excising of the frame and hot knife reflow or laser bonding to the card. In Fig. 1A, the metal lines are shown shorted together, which would allow easy electroplating of the tape before ball formation. Packages can be tested on tape after ball formation but before outer lead bonding. In Fi...