PURPOSE: To connect wiring patterns formed onto each insulating layer electrically and positively by electrically connecting each layer wiring pattern through a low resistance region formed to the surface of a semiconductor substrate.

CONSTITUTION: A low resistance region 7, into which impurity ions are doped, is formed at the specified place of the surface of a silicon semiconductor substrate 1, and the surface of the low resistance region 7 is coated with an insulating oxide film 8 with the exception of a part. A section, from which the low resistance region 7 is exposed, is used as a connecting section 9. A wiring patter 2 as an upper layer formed onto the surface of the semiconductor substrate 1 is connected electrically to the low resistance region 7 through the connecting section 9. Connection having small contact resistance is obtained through the low resistance region 7 shaped to the surface of the semiconductor substrate 1 in the wiring pattern 2 as the upper layer and the wiring pattern 5 of a T layer. When each wiring pattern is bonded, the wiring patterns 2, 5 as upper and lower layers are connected positively without etching the wiring patterns 5 as the lower layers.