| abstract |
There is a problem in the cost of a two-layer bump 41 by a conventional method. The reason is that the resist coating is performed twice (FIGS. 7 (d) and 8 (g)), the process is long, and the costs of the resists 35 and 38 are high. Since the resists 35 and 38 for plating are 10 to 20 times thicker than resists in other processes, the material cost is increased. In the method for forming a two-layer bump 20 of the present invention, a small hole 16 is first formed in the same resist 15A to be used for plating a copper bump 17, and the second time a hole 18 is widened and a gold skin 19 is formed. Used for plating. Since the same resist 15A is used twice by changing the sizes of the holes 16 and 18, the consumption of the resist can be reduced to about half of the conventional amount. Moreover, the resist coating process can be reduced once. [Selection] Figure 2 |