Assembly adhesives in film format are an increasing topic of interest. They have similar formulations to traditional die attach pastes and assembly pastes but they come in sheets with custom dimensions that can be applied directly on the die or substrate. These flat and even conductive and non conductive die attach films ensure perfect uniformity and a very controlled bond line thickness. Additionally, there’s minimal overflow during assembly and custom die-cut designs can also be produced.
Industry trends for electronic devices can be summarized as Miniaturization, High power dissipation, Higher reliability, Thinner devices. All these trends have certain drawbacks and challenges for die attach and assembly pastes. Miniaturiazation means that it is easier to contaminate the adjacent wirebond pads by flow and bleed from the adhesive. Higher reliability faces difficulties because of the difficult set-up and process maintenance that can lead to incomplete coverage, uneven fillet height, suck back, and other issues. In addition to that, the warpage of the die makes dies harder to stack, while contamination of the die surface from the adhesive is a possibility. Finally, thinner devices are prone to inconsistent fillets that can reduce reliability. The position accuracy is very important to avoid tilt while the contamination of the wire bonding pads by flow and bleed from the adhesive still lurks. All of the above problems can be resolved by assembly adhesives due to their controlled flow.