| 摘要 |
PURPOSE:To supply a constant quantity of solder to an outer lead when a package LSI is soldered individually by thermally transferring a pellet, obtained by cutting a solder wire having a diameter corresponding to a predetermined volume and the pitch of outer lead, to the outer lead of a QFP type package LSI. CONSTITUTION:In a pallet 16, rectangular recesses 17 and vacuum suction holes 18 are made in four directions for each lead of a QFP and a pellet 19 having predetermined cross-sectional dimension and length is placed in the recess 17. After flux is applied to the pellet 16, the QFP lead 21 is aligned to bring the solder pellet 19 into contact with the lead 21 and then the solder is thermally transferred to the QFP lead 21. This method allows uniform formation of predetermined quantity of solder required for reliable soldering of the outer lead of QFP semiconductor package to a printed board thus allowing the soldering without feeding any solder to the pad on the board. |
