Semiconductor device and method of manufacturing the same
View Patent ↗The invention is directed to a semiconductor device having a via hole and a method of manufacturing the same that achieve both the prevention of a barrier layer insufficiently covering the via hole and the control of via resistance at the same time. A semiconductor substrate having a pad electrode on its front surface is prepared. The semiconductor substrate is etched from its back surface to its front surface to form a via hole exposing the pad electrode. A first barrier layer is then formed in the via hole by a sputtering method or a PVD method and reverse-sputtering (etching). By this reverse-sputtering, the barrier layer on the bottom of the via hole is removed to expose the pad electrode. A second barrier layer is then formed on the pad electrode exposed in the via hole. The via resistance is controlled by adjusting only the thickness of the second barrier layer.
1. A semiconductor device comprising:
a semiconductor substrate having a first surface and a second surface opposite from the first surface;
a first conductor disposed on the first surface of the semiconductor substrate;
a second conductor disposed on the second surface of the semiconductor substrate;
a via hole penetrating through the semiconductor substrate and connecting the first conductor and the second conductor;
a barrier layer disposed in the via hole; and
a penetrating electrode disposed on the barrier layer in the via hole so as to electrically connect the first and second conductors,
wherein the barrier layer comprises a first conducting barrier layer formed on an inner sidewall of the via hole and a second conducting barrier layer formed at a bottom end of the via hole,
the first conducting barrier layer comprises an upper wall portion and a lower wall portion that are disposed on the inner sidewall of the via hole, and the lower wall portion is thicker than the upper wall portion and located at the bottom end of the via hole,
the bottom end of the via hole is located on the side of the first surface of the semiconductor substrate,
the first and second conducting barrier layers are disposed on the second surface of the semiconductor substrate so that the first conducting barrier layer is between the second conducting barrier layer and the second surface of the semiconductor substrate, and
the second conducting barrier layer is, at least partially, physically in contact with the first conductor such that the whole bottom end of the via hole is covered by the barrier layer.
2. The semiconductor device of claim 1 , further comprising a seed layer formed on the second conducting barrier layer.
3. The semiconductor device of claim 1 , wherein the total thickness of the first and second conducting barrier layers is constant at the bottom end and on the sidewall of the via hole.
4. The semiconductor device of claim 1 , further comprising a supporting body attached to the first surface or the second surface of the substrate.
5. The semiconductor device of claim 1 , wherein the second conducting barrier layer comprises a material different from a material of the first conducting barrier layer.
6. The semiconductor device of claim 1 , wherein the second conducting barrier layer comprises laminated layers.
7. The semiconductor device of claim 1 , wherein a thickness of the second conducting barrier layer at the bottom end of the via hole is smaller than a thickness of the second conducting barrier layer on the second surface of the semiconductor substrate.
8. The semiconductor device of claim 1 , wherein the second conducting barrier layer is not formed on the first conducting barrier layer formed on the inner sidewall of the via hole except at the bottom end of the via hole.
9. The semiconductor device of claim 1 , wherein the total thickness of the first and second conducting barrier layers is smaller at the bottom end of the via hole than on the sidewall of the via hole.