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Browse Prior Art Database

Rigid Dish Smart Card

IP.com Disclosure Number: IPCOM000036238D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 82K

Publishing Venue

IBM

Related People

Castrucci, PP: AUTHOR [+4]

Abstract

This article describes fabrication techniques useful in the construction of smart cards (credit cards, medical history cards, etc.) which will protect the semiconductor chip or chips embedded in the plastic package from mechanical abuse and destruction.

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

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Rigid Dish Smart Card

This article describes fabrication techniques useful in the construction of smart cards (credit cards, medical history cards, etc.) which will protect the semiconductor chip or chips embedded in the plastic package from mechanical abuse and destruction.

Smart cards are frequently subjected to user abuse by flexing when being carried in personal wallets, etc. Methods are shown for protecting the card by utilizing structures that improve mechanical rigidity in the region of the chip. The ideal smart card would contain a single chip with necessary functions, e.g., a typically secure EEPROM, CPU, random- access memory (RAM), ROM, serial bus and I/O ports. The card may also contain some non-volatile memory and extensive on-chip self-test capability. The recognized standard (ISO/AFNOR) would be observed requiring eight I/O bond pads, etc. Such a chip has yet to be fabricated; however, all the technology exists to build the ideal smart card. Near- in sophisticated smart card technology can be achieved with two chips as schematically depicted in Fig. 1. A planar circuit structure 10 is shown using a special microprocessor chip 11, and existing EEPROM 12.

Referring to Fig. 2, a folded flex structure affords superior device protection through a combination of device tape automated bonding (TAB) technology, planar construction, and device bonding directly to a rigid dish. Also, the rigid dish provides a sound surface for I/O card contact, and allows folding to minimize card surface area over which the electrical components may be subjected to stress from bending. The two- chip smart card shown in Fig. 1 requires many interconnections compared with only eight linear TAB bonds for the folded flex structure.

Connections between chip tabs and card I/O are made through a copper personalized flex printed circuit. Polyimide/adhesive is used to bond the flex printed circuit to the rigid dish with the copper...