A semiconductor substrate assembly includes a semiconductor material layer, a first isolation layer, a second isolation layer, a first conductive pillar, and a second conductive pillar. The semiconductor material layer has a first surface and a second surface opposite to the first surface. The first isolation layer is located on the first surface of the semiconductor material layer. The second isolation layer is located on the second surface of the semiconductor material layer. The first conductive pillar, supplied with a first voltage, penetrates the semiconductor material layer, the first isolation layer, and the second isolation layer. The second conductive pillar is supplied with to a second voltage, and a part of the second conductive pillar is formed in the second isolation layer, the second conductive pillar penetrates the second isolation layer and touches the second surface of the semiconductor material layer.