PURPOSE: To accurately form bonding bumps in high density at the prescribed positions on a substrate by a simple method by disposing metal balls at the prescribed positions on a transparent plate with less moisture, placing a plate to be connected thereon, and heat-treating it to fusion-bond the prescribed positions of the plate to be connected with the balls.

CONSTITUTION: Semispherical recesses 17 are formed at the prescribed positions of a transparent plate (e.g., a glass plate) 16 with less moisture for melted metal balls 4. Metal balls 4 are filled in the recesses 17. An Si wafer 3 is placed on the balls 4 by direction the connecting portion 5 of the wafer 3 downward, a weight plate 22 is placed on the wafer 3, the prescribed pressure is applied, and heat treated as prescribed in a reflowing furnace. The balls 4 are partly melted, fusion-bonded to the contacting portion 5 of the wafer 3 to form bonding bumps.