Method For Fabricating Conductive Structures of Substrate

Abstract

A method for fabricating a conductive structure of a substrate includes the steps of: providing an insulating substrate having opposite first and second surfaces and forming an insulating adhesive film on the second surface of the insulating substrate; forming at least a through hole penetrating the insulating substrate and the insulating adhesive film and forming a conductive foil on the insulating adhesive film so as to cover the through hole; and forming a shielding material on the conductive foil and the second surface of the insulating substrate and performing an electrochemical deposition process through the conductive foil so as to fill the through hole with a conductive material along a direction towards the first surface of the insulating substrate, thereby preventing the formation of voids in the through hole and hence reducing the overall resistance and preventing a blister effect from occurring.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to methods for fabricating conductive structures of substrates, and more particularly, to a method for filling a conductive material in a through hole of a substrate.[0003]2. Description of Related Art[0004]To form a conductive structure in a substrate, a method as disclosed by Taiwan Patent No. 540,279 can be performed. First, at least a though hole is formed in the substrate. Then, a conductive layer is formed on the entire surface of the substrate by sputtering, and a dry film is attached to the conductive layer and patterned by exposure and development. Subsequently, an electroplating process is performed by using the conductive layer as a current conductive path, thereby filling the through hole with a conductive material and forming a circuit layer on the substrate.[0005]However, during the electroplating process, the through hole is filled with the conductive material from the sidewa...

AI Technical Summary

Benefits of technology

The present invention uses an electrochemical deposition process to fill through holes in an insulating adhesive film with conductive material. This avoids the formation of voids and ensures a continuous connection between circuit layers. Planarization of the insulating substrate surface also reduces circuit layer thickness and improves area utilization, reducing thermal resistance.

Problems solved by technology

Consequently, voids may be formed in the conductive material of the through hole, thus increasing the overall resistance and decreasing the conductivity of electrical signals.

Moreover, voids may expand in a high temperature environment so as to cause a blister effect.

Furthermore, the circuit layer usually has a dimple formed at or close to the position of the through hole, thus resulting in an uneven surface of the circuit layer and hence adversely affecting a subsequent die bonding process.

To overcome the drawback, the die bonding process is performed at a position far from the dimple, which, however, reduces the utilization rate of the substrate surface and increases the cost.

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