Method for manufacturing semiconductor device, method for forming alignment mark, and semiconductor device
View Patent ↗A method for manufacturing a semiconductor device includes the steps of: forming a first dielectric film on a substrate; etching the first dielectric film in a plug forming region to form a first via hole; forming a first plug electrode in the first via hole; forming a conductive film on the first dielectric film where the first plug electrode is formed; selectively etching the conductive film to form a local wiring on the first plug electrode and to form a pad layer on the first dielectric film in a specified region; forming a second dielectric film on the first dielectric film, thereby covering the local wiring and the pad layer; selectively etching the second dielectric film, thereby forming a second via hole in the second dielectric film with the local wiring as a bottom surface, and an opening section in the second dielectric film with the pad layer as a bottom surface; forming a metal film on the second dielectric film, thereby embedding the second via hole and the opening section; and applying a CMP processing to the metal film to remove the metal film on the second dielectric film, thereby forming a second plug electrode in the second via hole and forming an alignment mark on the pad layer.
1. A method for manufacturing a semiconductor device, the method comprising:
forming a first dielectric film on a substrate;
forming a first conductive film on the first dielectric film;
forming a second dielectric film on the first conductive film;
etching the second dielectric film to form a first contact hole and an opening section;
forming a second conductive film on the second dielectric film such that the first contact hole and the opening section are filled with the second conductive film; and
removing a portion of the second conductive film to expose a surface of the second dielectric film where the first contact hole and the alignment mark are not formed, the opening section filled with the second conductive film forming an alignment mark; and
forming an oxidation barrier film on the second conductive film to protect the second conductive film from oxidation,
wherein the step of removing the portion of the second conductive film includes a chemical mechanical polishing method that removes another portion of the second conductive film located at edges of the opening section such that a step difference between a surface of the second dielectric layer and the alignment mark is minimized.
2. The method of manufacturing the semiconductor device according to claim 1 , the substrate including an impurity diffusion region, the method further comprising:
etching the first dielectric film to form a second contact hole before the forming of the first conductive film, the second contact hole touching the impurity diffusion region; and
filling the second contact hole with a third conductive film, the second contact hole and the first contact hole sandwiching a portion of the first conductive film.
3. The method of manufacturing the semiconductor device according to claim 2 , the forming of the first conductive film including etching the first conductive film to form a first conductive region and a second conductive region, the first conductive region being positioned between the first contact hole and the second contact hole, the second conductive region being positioned apart form the first conductive region and being positioned between the alignment mark and the first dielectric film.
4. The method of manufacturing the semiconductor device according to claim 1 , the first conductive film being configured to be formed of a first layer and a second layer, the first layer including titanium nitride and the second layer including titanium.
5. The method of manufacturing the semiconductor device according to claim 1 , the first conductive film and the second conductive film including tungsten.
6. The method of manufacturing the semiconductor device according to claim 1 , the oxidation barrier film being configured to be formed of a plurality of layers.
7. The method of manufacturing the semiconductor device according to claim 6 , the plurality of layers including a TiAlN layer, an Ir layer and an IrOX layer, the Ir layer being positioned between the TiAn layer and the IrOX layer.
8. The method of manufacturing the semiconductor device according to claim 1 , the method further comprising:
forming a ferroelectric film above the second dielectric film; and
heating the substrate at a temperature between 600 and 800 degrees Celsius.
9. The method according to claim 1 , wherein the second conductive film that forms the alignment mark gradually tapers in a direction toward the substrate at the edges of the opening section relative to an upper surface of the second dielectric film so that the step difference is minimized.