Method for joining metal or conductive miniature columnar pins to the electrode pad portion of a workpiece.

Abstract

This invention provides a method for joining a workpiece to an electrode pad portion that reduces the manufacturing cost of pins by using simple cylindrical, extremely small columnar pins, allows for efficient mounting, and ensures that the extremely small columnar pins are firmly joined without tilting. [Solution] The method involves activating the flux contained in the printed solder paste at a temperature that is high enough to activate, liquefy, and volatilize, but not high enough to dissolve the solder particles, thereby homogenizing the unevenly applied solder paste particles. This is then allowed to cool naturally at room temperature. Flux is printed again on top of this. A metal mask is used to erect tiny metal or conductive columnar pins 5 on top of the printed flux. The metal mask is then peeled away from the electrode pad area. Finally, the workpiece 2 on which the metal or conductive columnar pins are mounted is reflowed at a high temperature to melt the solder particles and bond the metal or conductive columnar pins to the electrode pad area of ​​the workpiece.

Claims

[Claim 1] A method for joining a metal or conductive miniature columnar pin to an electrode pad portion of a workpiece, characterized by comprising the following steps a. to h. a. A process of applying a fixing agent such as solder paste to the electrode pad portion of a workpiece such as a semiconductor wafer or printed circuit board by printing. b. A step of activating the flux contained in the solder paste by using an oven or the like to a temperature at which the flux becomes active, begins to liquefy, and volatilizes. c. A process to flatten the solder paste particles by using the flux contained in the printed solder paste, which is applied to the electrode pad area by liquefying the flux, thereby leveling the uneven height of the solder paste particles. d. A process of allowing the system to cool naturally at room temperature in this state. e. A step in which flux is printed again as an adhesive for metal or conductive miniature columnar pins in order to mount metal or conductive miniature columnar pins on the electrode pad portion, where the solder particles have remained flattened and undissolved on the electrode pad portion. f. A step of erecting metal or conductive miniature columnar pins on the electrode pad portion of the workpiece on which flux has been printed, by passing a metal mask through it. g. A step of removing the metal mask from the electrode pad area of ​​the workpiece after the mounting of the metal or conductive miniature columnar pins is complete. h. After removing the metal mask, the process involves reflowing the workpiece, on which the metal or conductive miniature columnar pins are mounted, at a high temperature to melt the solder particles and join the metal or conductive miniature columnar pins to the electrode pad portion of the workpiece.

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