US 6,631,558 B2 · Blind via laser drilling system

Abstract

A method for laser drilling blind vias at multiple depths in a multilayer panel comprising forming a panel having a plurality of conductive layers and a plurality of dielectric layers interposed therebetween, a first relief in the first conductive layer, a second relief in a second conductive layer, and a blind pin in the third conductive layer, the first and second reliefs and blind pin being aligned. The panel is irradiated, laser energy passing through the first and second reliefs to remove material from the first and second dielectric layers and then plated, thereby forming a blind via from the first to third conductive layers through the second conductive layer. A printed circuit board has two conductive layers by a dielectric layer, and a blind via electrically interconnecting the first and third conductive layers through the first and second dielectric layers and second conductive layer. The blind via can be round or oblong. Blind vias can be daisy-chained and/or buried under successive dielectric and conductive layers for additional level interconnects.

Claims20

Dependent claims

A method for laser drilling blind vias at multiple depths in a multilayer panel, comprising:

forming a panel comprising:
a first conductive layer patterned to form a first relief;
a first dielectric layer;
a second conductive layer patterned to form a second relief, said second relief being laterally aligned with the first relief in the first conductive layer;
a second dielectric layer;
and
a third conductive layer including a blind pin aligned with said first and second reliefs;
relatively positioning the panel and a drilling laser so that the first relief is in alignment with the laser;
irradiating the panel with laser energy, wherein said energy is directed so as to reflect off the surface of the first conductive layer while passing through said first and second reliefs to remove material from the first dielectric layer and second dielectric layer and reflecting off the blind pin;
thereby forming a first blind via from the first to third conductive layers through the second conductive layer;
and
the panel further comprises a plurality of reliefs in the first conductive layer and a corresponding plurality of blind pins laterally aligned with and below said plurality of reliefs, wherein irradiating the panel includes irradiating with a single pulse of laser energy more than one relief in the first conductive layer, thereby forming multiple blind vias with said pulse of laser energy.

9 more elements

Dependencies are inferred from the claim text.

Blind via laser drilling system

Life of this patent

Blind via laser drilling system

Life of this patent

Abstract

Claims20