METHOD AND APPARATUS FOR DISPENSING FLUX-FREE SOLDER ON A SUBSTRATE

An apparatus for dispensing flux-free solder comprises a dispenser head (2) with a stamp (5) to which ultrasound can be applied. Solder is dispensed by: a) moving the dispenser head (2) above a next substrate place, b) lowering the stamp (5) until the working surface (11) of the stamp (5) touches the substrate place or is located at a predetermined height above the substrate place, c) dispensing solder by: C1) advancing the solder wire (8) until the solder wire (8) touches the substrate place, in such a manner that the tip of the solder wire (8) touches the substrate place within a recess (12) of the stamp (5), C2) further advancing of solder wire (8) to melt a predetermined quantity of solder, and C3) retracting the solder wire (8), d) moving the dispenser head (2) to distribute the solder on the substrate place, and simultaneously applying ultrasound to the stamp (5), and e) raising the stamp (5).