Semiconductor device and method for manufacturing the same
A highly reliable semiconductor device suitable for miniaturization and high integration is provided. The semiconductor device includes a first insulator; a transistor over the first insulator; a second insulator over the transistor; a first conductor embedded in an opening in the second insulator; a barrier layer over the first conductor; a third insulator over the second insulator and over the barrier layer; and a second conductor over the third insulator. The first insulator, the third insulator, and the barrier layer have a barrier property against oxygen and hydrogen. The second insulator includes an excess-oxygen region. The transistor includes an oxide semiconductor. The barrier layer, the third insulator, and the second conductor function as a capacitor.
1. A method for manufacturing a semiconductor device, comprising the steps of:
forming a first insulator over a first transistor, a channel formation region of the first transistor comprising part of a semiconductor substrate;
forming a second transistor over the first insulator, a channel formation region of the second transistor comprising an oxide semiconductor;
forming a second insulator over the second transistor;
forming an opening in the second insulator, the opening reaching the second transistor;
forming a first conductor over the second insulator to embed the first conductor in the opening of the second insulator;
removing part of the first conductor to expose a top surface of the second insulator;
forming a barrier layer over the first conductor;
performing oxygen plasma treatment on the barrier layer and the second insulator;
forming a third insulator over the barrier layer and the second insulator; and
forming a second conductor over the third insulator,
wherein the barrier layer, the third insulator, and the second conductor overlap with each other and function as a capacitor, and
wherein each of the first insulator, the barrier layer, and the third insulator has a barrier property against oxygen and hydrogen.
2. The method for manufacturing the semiconductor device according to claim 1 , wherein the second insulator comprises silicon oxynitride formed by a CVD method.
3. The method for manufacturing the semiconductor device according to claim 1 , wherein the barrier layer comprises tantalum nitride formed by an ALD method.
4. The method for manufacturing the semiconductor device according to claim 1 , wherein the barrier layer comprises aluminum oxide formed by an ALD method.
5. The method for manufacturing the semiconductor device according to claim 1 , wherein the third insulator comprises aluminum oxide formed by a sputtering method.
6. The method for manufacturing the semiconductor device according to claim 1 , wherein an impurity included in the second insulator is removed by the oxygen plasma treatment.