Nordson MARCH has a variety of plasma treatment solutions specifically designed for the unique needs of advanced semiconductor packaging and assembly (ASPA), wafer level packaging (WLP) and micro electro mechanical (MEMS) assembly. Plasma applications include cleaning, wire bond improvement, descum, bump adhesion, stripping and etch.
High reliability and yield in the manufacturing of advanced integrated circuits can be difficult to achieve as package sizes decrease and the use of advanced materials increases. Many manufacturing challenges can be improved or overcome by using a suitable plasma treatment, including improving die attach, increasing wire bond strength, eliminating flip-chip underfill voids, and reducing package delamination.
Die Attach - Plasma cleaning of substrates improves the adhesion of the die attach epoxy via surface activation, which provides an improved bond between the die and the substrate. Better bonds improve heat dissipation. In addition, plasma treatment removes oxidation from the metal surface to ensure void-free die attachment. Oxidation can adversely affect die attachment when eutectic solder is used as an adhesive material for die bonding.
Wire Bond - Gas plasma technology can be used to plasma clean pads prior to wire bonding to improve bond strengths and yields. Poor bond strengths and low yields are often due to upstream contamination sources or the selection of materials in advanced packaging.
Underfill - Plasma surface preparation prior to the underfill process has proven to increase underfill wicking speed, increase fillet height and uniformity, minimize voiding, and improve underfill adhesion. The mechanisms for these improvements include surface energy and surface chemical composition changes.
Encapsulation & Molding - Plasma processing improves adhesion of mold compounds by increasing the substrate surface energy. The improved adhesion increases package reliability.
MEMS - MEMS devices such as accelerometers, roll-over sensors and air bag deployment sensors require advanced plasma treatments during their manufacture in order to improve the device yield and long-term reliability. Typical plasma applications include device cleaning, photoresist descum, stripping of materials like photoresist and benzocylcobutene (BCB), etching redistribution lines, and removing contamination. Other applications include surface cleaning and roughening; chemical bond activation to improve bondability; and increasing wettability and uniformity of liquid flow over the wafer surface.