Patent ID: 8648668
Filing Date: 2014-02-11
Classification: H05K

Abstract:
1. A structure for precision control of electrical impedance of signal transmission circuit board, comprising: a substrate, which has a first surface and a second surface; a plurality of first signal transmission lines, which is formed on the first surface of the substrate, the first signal transmission lines being spaced from each other by a predetermined distance to form a plurality of wiring sections that are covered by the first signal transmission lines and a plurality of spacing sections that are not covered by the first signal transmission lines on the first surface of the substrate; a first covering insulation layer, which is formed on the first surface of the substrate and covers a surface of each of the first signal transmission lines and each of the spacing sections, the first covering insulation layer having a surface that forms a first height at a portion thereof corresponding to the wiring sections, the surface of the first covering insulation layer forming a second height at a portion thereof corresponding to the spacing sections, the first height and the second height forming a height difference therebetween; and a first conductive shielding layer, which is formed on a surface of the first covering insulation layer; characterized in that a first flattening insulation layer is formed between the surface of the first covering insulation layer and the first conductive shielding layer, the first flattening insulation layer filling up the height difference, so that the first conductive shielding layer shows a substantially consistent height with respect to both the wiring sections of the substrate and the spacing sections of the substrate, wherein the substrate, the first signal transmission lines, the first covering insulation layer, the first flattening insulation layer, and the first conductive shielding layer collectively form a single-sided signal transmission circuit board.