Patent ID: 9301405
Filing Date: 2016-03-29
CPC Classification: H01L,H05K

Claim Text:
1. A method for manufacturing microthrough-hole in circuit board, comprising: preparing a carrier plate; electroplating a metal layer on the carrier plate; forming a first circuit with a plurality of copper pads on one surface of the metal layer; covering the first circuit with a photoresist layer, wherein a copper window between two of the copper pads is not covered; etching the metal layer beneath the copper window until the carrier plate is exposed and removing the photoresist layer; sequentially forming an insulation layer and a second circuit on the first circuit and the copper windows, the second circuit layer having a stop pad corresponding to the copper window; removing the carrier plate; employing a drilling process to upward drill through the insulation layer corresponding to the copper window and stop at the stop pad so as to form a microthrough-hole beneath the stop pad; and forming a conductive layer in the microthrough-hole to electrically connect the first circuit and the second circuit.