Electrical testing method of interposer

An electrical testing method of an interposer, comprising the steps of:

• providing an interposer, the interposer comprising:
• a substrate having a first surface with a plurality of first conductive pads and a second surface opposite to the first surface, the second surface having a plurality of second conductive pads;
• a plurality of conductive through holes penetrating the first and second surfaces of the substrate and electrically connecting the first and second conductive pads;
• and
• a first removable electrical connection structure formed on the first surface and electrically connecting a portion of the first conductive pads,
• wherein the first removable electrical connection structure is a metal layer or a wiring layer formed on the first conductive pads and the first surface, and
• wherein the first conductive pads further have a first Under bump metallurgy (UBM) layer formed thereon and the second conductive pads further have a second UBM layer formed thereon, such that the first removable electrical connection structure is interposed between the first conductive pads and the first UBM layer, and a second removable electrical connection structure is interposed between the second conductive pads and the second UBM layer;
• electrically connecting a plurality of probes to the interposer to test the interposer;
• and removing the first removable electrical connection structure.