a semiconductor device substrate has fine terminals with a small pitch and is able to be easily produced at a low cost without using a special process . a mounting terminal has a pyramidal shape and extending between a front surface and a back surface of a silicon substrate . an end of the mounting terminal protrudes from the back surface of the silicon substrate . a wiring layer is formed on the front surface of the silicon substrate . the wiring layer includes a conductive layer that is electrically connected to the mounting terminal .