| 摘要 |
PROBLEM TO BE SOLVED: To provide a solder paste which is preserved for a long period of time at normal temperature, and excellent in printability of fine patterns of a high-density circuit by using a flux having excellent wettability and lead-free solder powder. SOLUTION: At least a part of an activator in a flux is used in a coated particle manner where the activator is coated with a thermoplastic substance. The coated particles of the activator are preferably small particles in a nearly mono-dispersed state of the integrated volume grain size distribution in which the average grain size is in a range of 0.1-10μm, the 10% diameter is≥1/2 of the 50% diameter, and the 90% diameter is≤1.5 times the 50% diameter by passing an emulsion of the activator through a porous film (ex. a porous glass film). COPYRIGHT: (C)2007,JPO&INPIT
|
