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A novelle technique to implement a Faraday cage structure in a cavity down PBGA package

IP.com Disclosure Number: IPCOM000011865D
Original Publication Date: 2003-Mar-20
Included in the Prior Art Database: 2003-Mar-20
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Abstract

The present work discloses a technique to electrically connect a Copper stiffener that is part of a cavity down electronic plastic ball grid array package (PBGA) to its printed circuit laminate section.

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A novelle technique to implement a Faraday cage structure in a cavity down

PBGA package

The present work discloses a technique to electrically connect a Copper stiffener that is part of a cavity down electronic plastic ball grid array package (PBGA) to its printed circuit laminate section.

     As shown on Fig.1 the module configuration presents a Copper stiffener that, as a result of manufacturing process techniques and flows, ends in being attached with an insulating adhesive to the printed circuit board (PCB) laminate section leaving the Copper slug electrically floating.

     In an expanding application space for this packages there is the need to have this large metal features no longer floating from the electrical stand point. It becomes important to have them connected to electrical circuits, generally to a Ground potential, which are present on the PCB section. This accomplish a higher EMI shielding from environmental electromagnetic noise and finally becoming a possible integration of a full Faraday's cage that completely surrounds the emitting or receiving device.

Stiffener

ChipPCB

Connecting Module Ball Grid Array Insulating Adhesive

Fig. 1 Standard Cavity Down Module Configuration

     This discloses a technique to establish an electrical connection of the Cu slug to a receiving GND or circuits pads through a single or a series of holes in the stiffener as shown in Fig.2. By the insertion of a joining material, like a solder alloy or a polymer with conductive partic...