SEMICONDUCTOR DEVICE
After opening a via hole, the bottom portion and the top portion are rounded by etching performed twice. As a result, resistance of the via hole can be reduced and its quality and life can be enhanced.
1 . A semiconductor device comprising:
an interconnection layer;
a silicon oxide layer laminated on the interconnection layer;
a via hole penetrating through the silicon oxide layer and reaching to the interconnection layer;
a barrier metal covering a whole surface in the via hole; and
a plug filled in the via hole,
wherein a top portion and a bottom portion of the via hole are rounded.
2 . The semiconductor device according to claim 1 , wherein a size of the top portion and the bottom portion in a direction of a depth of the plug is respectively among 5% to 15% to a depth of the plug.
3 . The semiconductor device according to claim 1 , wherein a size of the top portion and the bottom portion in a direction of a depth of the plug is respectively approximately 12% to a depth of the plug.
4 . The semiconductor device according to claim 1 , wherein the interconnection layer comprises:
an aluminum layer; and
a TiN (titanium nitride) film formed on the aluminum layer, and
the barrier metal is formed by Ti/TiN spattering applied to the whole surface in the via hole, and
the plug is formed by a tungsten.
5 . A manufacturing method of a semiconductor device comprising:
forming an interconnection layer;
forming a silicon oxide layer on the interconnection layer;
forming a via hole penetrating through the silicon oxide layer and reaching to the interconnection layer;
forming a barrier metal covering a whole surface in the via hole; and
forming a plug filled in the via hole,
wherein the forming the via hole comprises:
forming a rough profile of the via hole by dry etching;
trimming the via hole by RF (Radio Frequency) etching after the forming the rough profile; and
stopping the RF etching by a predetermined timing after the trimming.
6 . The manufacturing method of the semiconductor device according to claim 5 , wherein a size of the top portion and the bottom portion in a direction of a depth of the plug is respectively among 5% to 15% to a depth of the plug.
7 . The manufacturing method of the semiconductor device according to claim 5 , wherein a size of the top portion and the bottom portion in a direction of a depth of the plug is respectively approximately 12% to a depth of the plug.
8 . The manufacturing method of the semiconductor device according to claim 5 , wherein the interconnection layer comprises:
an aluminum layer; and
a TiN (titanium nitride) film formed on the aluminum layer, and
the forming the barrier metal comprises:
forming the barrier metal by Ti/TiN spattering applied to the whole surface in the via hole, and
the forming the plug comprises:
growing a tungsten film on a whole surface of the barrier metal in the via hole; and
applying CMP (Chemical Mechanical Polishing) to the tungsten film after the growing.