In the etching step, the light of a laser (not shown) is irradiated on the precoat 60 to etch at least a portion of the precoat 60, thereby forming a pattern 50 having a groove shape.

As shown in FIG. 7, the chip-mounting substrate is formed in a size far smaller than a coin. The pattern 50 is formed on the chip-mounting substrate having such a small size through the use of the laser. It is possible to accurately form a fine pattern 50 on the chip-mounting substrate. The pattern 50 is disposed at least one of the two conductive portions of the metal substrate 10 divided by the insulating portion 20.

In the present embodiment, the pattern 50 is disposed in the two conductive portions of the metal substrate 10 divided by the insulating portion 20. That is to say, the pattern 50 is disposed on both sides of the insulating portion 20. Furthermore, the pattern 50 is formed on the bottom of the cavity 40 and is disposed inside the cavity 40. Alternatively, the pattern 50 and the metal layer 30 may be disposed on only one of the two conductive portions of the metal substrate 10 divided by the insulating portion 20.

In the etching step, an uneven portion is formed by the laser on the upper surface of the metal substrate 10 in a region corresponding to the pattern 50.