The TF 36 is a no-clean tack flux for use with ball grid arrays (BGAs) and chip-scale packages (CSPs). It features high tack and proper wetting to diverse surfaces, and can be reflowed in either air or nitrogen. The clear residue left by the flux requires no solvent cleaning. For attaching bumped chips, the series offers TF 37, 38, and 54 &#151 all of which can attach chips to various substrates. TF 37 offers low residue and a synthetic oligomer and rheology modifier formula that produces a high tolerance for thermal cycling. The TF 38 leaves a minimal clear residue that may be left or removed with cosolvents, saponifiers, or both. The TF 54 features a nonionic surfactant, tackifying agent, and amine hydrohalide formula that offers high solderability for assorted finishes and ease-of-cleaning in low standoff applications. This activated surfactant blend is water-soluble. Heraeus Contact Materials Division, Hanau, Germany, www.heraeus.com.