In the present invention, it is also preferable to set the film thickness of the metal layer so that the metal layer fuses totally into the alloy solder when fusing the alloy solder, and so that when cooling the alloy solder {TAIL ~ at least some} of {HEAD ~ the alloy solder} is deposited 
In the present invention , it is also preferable to set the film thickness of the metal layer so that the metal layer fuses totally into the alloy solder when fusing the alloy solder , and so that when cooling the alloy solder { TAIL ~ at least some } of { HEAD ~ the alloy solder } is deposited
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH