PURPOSE:To stabilize and increase joint strength between a package substrate and a nail head pin, and to improve productivity by forming the shape of the head of the nail head pin joined with an electrode pad in a conical shape using a joint surface with the electrode pad as a base. CONSTITUTION:Conical heads 11a are formed at one ends of nail head pins 11 joined with each electrode pad 3 of a package substrate 2 and composed of an iron-nickel group alloy, and a wax material 4 as a joint material is applied to the heads 11a. Load shown in an arrow (b) is applied to the nail head pin 11 from the upper section of the nail head pin by positioning a weight on the projecting end section side of the nail head pin 11, but the molten wax material 4 pushed out from the pushing surface of the head 11a spreads toward the side face of the head 11a and the peripheral section of the electrode pad 3 at that time. When the wax material 4 is solidified, stress (f) capable of being broken down into a vector f1 in the horizontal direction and a vector f2 in the vertical direction is generated in the direction of a wetting angle theta, and the vector f2 in the vertical direction can be diminished by reducing the wetting angle theta.
展开▼
