SELECTIVELY CONDUCTIVE ADHESIVE INTERCONNECT

Publishing Venue

Motorola

Related People

Abstract

The selectively conductive interconnect system is a method of using a conductive adhesive that is con- ductive only in key areas where electrical or thermal conductivity is required. This adhesive system is designed to replace metal alloys for many applications in electronics. Depicted in the blow-up drawing below is the interconnection of a flip chip die (A) to a printed circuit board (PCB) (C) using an anisotropic adhesive (B) that is conductive only in the areas where the bumps on the bottom of the die and the corre- sponding pads on the PCB are located.

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MOTOROLA INC. Technical Developments Volume 13 July 1991

SELECTIVELY CONDUCTIVE ADHESIVE INTERCONNECT

by Frank Juskey, Bruce Freyman and Anthony Suppelsa

  The selectively conductive interconnect system is a method of using a conductive adhesive that is con- ductive only in key areas where electrical or thermal conductivity is required. This adhesive system is designed to replace metal alloys for many applications in electronics. Depicted in the blow-up drawing below is the interconnection of a flip chip die (A) to a printed circuit board (PCB) (C) using an anisotropic adhesive (B) that is conductive only in the areas where the bumps on the bottom of the die and the corre- sponding pads on the PCB are located.

  The advantages of the selectively conductive sys- tem over conventional anisotropic systems are hvo- fold. First is a reduced cost for precious metals since the costly conductive filler is only screened where electrical or thermal conduction is required. Secondly, an increased adhesive peel strength is achieved due to less filling of the adhesive to provide conductivity. It has been shown in peel test experiments that the unfill adhesive systems have greater peel strength over filled adhesive systems by a ratio of 6:l.

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