METHOD FOR SOLDER BONDING OF ARRAY OF CONTACT PAD AND ITS COMPONENT ASSEMBLY

PROBLEM TO BE SOLVED: To connect contact arrays on substrates which have different coefficients of thermal expansion by making a part covered with a solder bump in contact structure have smaller mean sectional area in a plane parallel to an array than the corresponding mean sectional area of each solder bump. SOLUTION: The part of the contact structure 100 which should be covered with the solder bump 110 is called a bonding part. This bonding part has mean sectional area smaller than the mean sectional area of the corresponding solder bump 110. The use of the contact structure 100 having the bonding part of mean sectional area less than about 60% of the mean sectional area of the corresponding solder bump makes it possible to limit a spread of solder to less than 50% of the distance between contact pads. Consequently, contact pad arrays on substrates having different coefficients of thermal expansion can be connected.