Further, the metal patterns 15a, 15b, 25a, 25b may have different distance from each other. According to an example illustrated in FIG. 46, the connection board 10C has a tapered exterior shape, and the metal patterns 15a, 15b, 25a, 25b are designed to be closer to each other at one side. Referring to FIG. 45, the metal patterns 15a, 15b, 25a, 25b of the connection board 10C establish an electrical connection between the upper and lower surfaces of the circuit board 100 in such a manner that exposed portions of the metal patterns 15a, 15b, 25a, 25b are spaced apart with a greater distance along the upper surface than along the bottom surface of the circuit board 100. According to one example, the pattern width between the metal patterns at the bottom surface of the circuit board may be between approximately 1 to 10 μm, 1 to 5 μm or 1 to 3 μm.

Referring to FIGS. 3 and 4, the metal patterns 15a, 15b, 25a, 25b may be formed through a circuit forming process including exposure, development and plating. For instance, the metal patterns 15a, 15b, 25a, 25b may be formed through any of common circuit pattern processes such as a semi additive process (SAP), a modified semi additive process (MSAP), an additive process and a subtractive process to have pitches of about 10-20 μm/10-20 μm.