Adhesives and sealants in electronics

Conductive Adhesives. Isotropically electrically conductive adhesives (ICAs) are widely used in the electronics industry when high-temperature soldering processes are unsuitable. Typical applications include silicon die attachment, component attachment in multi-chip modules (MCMs), surface mounted printed circuit board repair, and elec-tromagnetic/radio frequency (EMI/RFI) shielding. [Pg.83]

In all cases the conductive adhesive consists of high contents of conductive filler in an insulating polymer (adhesive) matrix. The choice of filler and adhesive matrix is dependent on the end use. [Pg.83]

Die attachment adhesives are normally epoxy- or polyimide-based and contain 70 - 80 wt % silver flake. Silver flake is the common choice for conductive adhesives as the oxide layer formed on the flake is also conductive. [Pg.83]

Polyimides became popular for die-bonding adhesives because they are cleaner (in terms of ionic contaminants) than equivalent epoxy products. The market at present, however, is dominated by high-purity epoxy adhesives. Polyimides are always applied from solvent solution and require higher curing temperatures than epoxies. They are stable to higher temperatures. Solvent-borne thermoplastics pastes (or cast-film preforms) have been used for some lower reliability die-attachment applications. [Pg.83]

Epoxies form the basis of products in the multi-chip module (MCM) bonding and surface mount technology (SMT) repair areas. Two-pack room-temperature products (amine cure) are common in repair applications. Two-pack systems with acid anhydride [Pg.83]