Electroplating method

Abstract

A substrate with a through-hole is immersed in a plating solution in a plating tank. A pair of anodes are disposed in the plating solution in the plating tank in facing relation to face and reverse sides, respectively, of the substrate in the plating solution. A plurality of plating processes are performed on the face and reverse sides by supplying pulsed currents respectively between the face side of the substrate and one of the anodes which faces the face side of the substrate, and between the reverse side of the substrate and the other anode which faces the reverse side of the substrate. A reverse electrolyzing process is performed on the face and reverse sides between adjacent plating processes by supplying currents in an opposite direction to the pulsed currents respectively between the face side of the substrate and one of the anodes, and between the reverse side of the substrate and the other anode.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an electroplating method for simultaneously plating both the face and reverse sides of a substrate which has a through-hole vertically penetrating in its interior to fill a plated film of metal such as copper or the like into the through-hole.[0003]2. Description of the Related Art[0004]A technique of forming a plurality of through-vias of a metal, vertically penetrating through a substrate, is known as a method to electrically connect the layers of a multi-layer stack of substrates such as semiconductor substrates. It is customary to make vertical through-vias in a substrate by simultaneously plating both the face and reverse sides of a substrate, which has through-holes vertically penetrating in its interior, thereby to fill a plated film of metal into the through-holes.[0005]There is known an electroplating apparatus for producing through-vias (see Japanese Patent No. 4138542). This e...

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Benefits of technology

[0011]The present invention has been made in view of the above situation. It is therefore an object of the present invention to provide an electroplating method for efficiently filling a plated film into a through-hole with a higher average plating current during plating to shorten the time required to perform the plating process and also ideally filling the plated film into the through-hole.

[0024]According to the present invention, as described above, the plural plating processes are performed, each for a predetermined period, on the face and reverse sides of the substrate by supplying pulsed currents respectively between the face side of the substrate and one of the anodes which faces the face side of the substrate, and between the reverse side of the substrate and the other of the anodes which faces the reverse side of the substrate. Accordingly, it is possible to fill a plated film into the through-hole efficiently with an increased average current value for thereby shortening a period of time required to plate the substrate. The reverse electrolyzing process performed between the plating processes is effective to dissolve plated films deposited on corners of the through-hole. Therefore, it is possible to ideally fill the plated film into the through-hole by growing the plated film preferentially at the center of the through-hole along the in-depth direction thereof.

Problems solved by technology

However, it is generally practically difficult to attempt to meet the ideal requirements and at the same time to fill the plated film efficiently into the through-hole to shorten the time required to perform the plating process.

Stated otherwise, the conventional electroplating processes have failed to achieve both the ideal filling of the plated film into the through-hole and the efficient filling of the plated film into the through-hole with a higher average plating current during plating.

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