Patent ID: 7927499

Claim:
A method for forming a blind hole in a substrate, comprising: (a) providing a substrate, the substrate sequentially comprising a first dielectric layer, a first copper layer, a second dielectric layer, a second copper layer, and a third dielectric layer, the second dielectric layer having a second dielectric layer through hole therein, the sidewall of the second dielectric layer having a first electroplating copper layer to electrically connect the first copper layer and the second copper layer, and the space defined by the first electroplating copper layer is filled with resin; and (b) forming a third dielectric layer through hole and a second copper layer through hole at positions corresponding to second dielectric layer through hole by etching through the third dielectric layer and the second copper layer with a laser, and forming a second cavity on the resin by using the laser, wherein an aperture of the second cavity is larger than that of the second copper layer through hole.