Apparatus For Dispensing Flux-Free Solder On A Substrate

Abstract

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

1 - 16 . (canceled) 
     
     
         17 . An apparatus for dispensing flux-free solder onto substrate places of a substrate, comprising
 a dispenser head, which is movable in two horizontal directions, and, optionally, in the vertical direction, comprising   an ultrasonic head,   a stamp having a working surface, which has a recess open toward a lateral surface of the stamp, wherein the stamp is fastenable on the ultrasonic head,   a wire feed having a nozzle having a longitudinal borehole configured to guide the solder wire, wherein the wire feed is mounted on the dispenser head such that an axis, which extends through the longitudinal borehole of the nozzle, enters at the lateral surface of the stamp into the recess and is incident on the substrate within a part of the working surface bounded by the recess, and   a cooling device, which is configured to keep the working temperature of the stamp at a predetermined temperature.   
     
     
         18 . The apparatus according to  claim 17 , further comprising
 a further cooling device for cooling the nozzle of the wire feed.   
     
     
         19 . The apparatus according to  claim 17 , further comprising
 a drive fastened on the dispenser head, which is configured to move the ultrasonic head with the stamp up and down in the vertical direction.   
     
     
         20 . The apparatus according to  claim 18 , further comprising
 a drive fastened on the dispenser head, which is configured to move the ultrasonic head with the stamp up and down in the vertical direction.   
     
     
         21 . The apparatus according to  claim 17 , wherein the recess of the stamp is coated with a material which is poorly wettable by flux-free solder. 
     
     
         22 . The apparatus according to  claim 18 , wherein the recess of the stamp is coated with a material which is poorly wettable by flux-free solder. 
     
     
         23 . The apparatus according to  claim 19 , wherein the recess of the stamp is coated with a material which is poorly wettable by flux-free solder. 
     
     
         24 . The apparatus according to  claim 20 , wherein the recess of the stamp is coated with a material which is poorly wettable by flux-free solder.