| abstract |
On a prepreg sheet (1) having parting films (2a and 2b) applied to its surface and back, there are formed product through holes (3), lamination recognizing mark through holes (7a and 7b) and X-ray recognizing mark through holes (8a and 8b). The product through holes (3) and the X-ray recognizing mark through holes (8a and 8b) are filled with a conductive paste (4) by masking the lamination recognizing mark through holes (7a and 7b). After this, the parting films (2a and 2b) are peeled to manufacture a circuit substrate. As a result, the lamination recognizing mark through holes (7a and 7b) are not filled with the conductive paste (4), so that a recognition mark of a high lamination precision can be easily obtained to provide a circuit forming substrate having an improved lamination precision, a high density and an excellent quality. |