Patent ID: 7243834

Claim:
A lead-free solder paste printing method comprising placing a metal mask ( 1 ) on a circuit board ( 2 ) having an electrode ( 21 ) formed in a predetermined pattern to join an end portion of a lead member ( 6 ), and moving a printing squeegee ( 4 ) along an upper surface of the metal mask ( 1 ) to thereby print a lead-free solder paste ( 30 ) on a surface of the electrode ( 21 ) on the circuit board ( 2 ), wherein the metal mask ( 1 ) has two openings ( 11 a , 11 b ) having centers on a line extending parallel to the longitudinal length of the lead member ( 6 ) and formed within a region corresponding to the electrode ( 21 ) on the circuit board ( 2 ) to join the end portion of the lead member ( 6 ), each having an elliptical non-circular shape, wherein the first ( 11 a ) of the two openings ( 11 a , 11 b ) which is positioned closer to said end portion of the lead member ( 6 ) is smaller than the other second opening ( 11 b ) in area, and two lead-free solder paste patterns ( 30 a , 30 a ) are printed on the electrode ( 21 ) by using the metal mask ( 1 ), the two solder paste patterns being arranged longitudinally of the lead member ( 6 ).