Browse Prior Art Database

Hollow Plating Forms for Creating Stress Relieved Leads

IP.com Disclosure Number: IPCOM000085437D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

McBride, DG: AUTHOR [+2]

Abstract

Many semiconductor devices or large-scale integrated (LSI) chips are electrically connected to their substrates by wires which form an arch between their end points, or use lead frame interconnections where the leads are bent or formed into loops before they are joined to the devices. However, it would be preferable to plate the leads in situ using a hollow form, for example, to create a strain relief loop to prevent the devices from being subjected to mechanical stresses, thermal stresses and because such interconnections can be made less expensively using a batch process.

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Hollow Plating Forms for Creating Stress Relieved Leads

Many semiconductor devices or large-scale integrated (LSI) chips are electrically connected to their substrates by wires which form an arch between their end points, or use lead frame interconnections where the leads are bent or formed into loops before they are joined to the devices. However, it would be preferable to plate the leads in situ using a hollow form, for example, to create a strain relief loop to prevent the devices from being subjected to mechanical stresses, thermal stresses and because such interconnections can be made less expensively using a batch process.

To create a supporting surface between the terminal sites, a hollow form is fabricated by first applying a plating sensitizer to a thin, solvent-soluble plastic film. A sensitizer, such as palladium chloride, can be used to define the area where a conductive metal plates out to create the leads on the thin plastic film. The film could be in sheet form while registration holes are punched therein and the sensitizer is printed on it.

When the sensitizer is dry, the printed, punched film is placed in a vacuum forming die, and when the vacuum is applied, the film is drawn into the cavity creating a shape 11 as shown in the figure for the formation of the strain relief loop in the areas 13 for the leads. A second piece of film 15 is placed on the bottom of the die set and the die is closed to bond the ends of the loop sheet 11 to the flat bott...