| 摘要 |
A method for forming inter-metal dielectric is disclosed. The method normally includes the following steps. First of all, a semiconductor wafer is provided. Then, forming a first metal layer on a portion of the substrate is carried out. A first dielectric layer is formed on the first metal layer and the substrate. Consequentially a tantalum nitride layer is formed on the first dielectric layer. A first photoresist layer can be formed on the tantalum nitride layer, especially first photoresist layer has a first pattern defining a trench area located over the first metal layer, and has a second pattern defining an etch stop area. The tantalum nitride layer will be etched by the first photoresist layer. A second dielectric layer is formed over the etched tantalum nitride layer and the first dielectric layer. The second photoresist layer can be formed on the second dielectric layer, especially the second photoresist layer has a first pattern substantially aligned with the first pattern of the first photoresist layer, and has a second pattern substantially aligned with the second pattern of the first photoresist layer. Next, etching the second dielectric layer by the second photoresist layer can be achieved, portion of the first dielectric layer over the first metal layer is further etched by the first pattern of the first photoresist layer. Thus trenches are formed in the first dielectric layer and the second dielectric layer. Then the tantalum nitride layer is deposited into the trenches, especially barrier layer is formed on top surface of the trenches. A seed layer is formed on sidewalls of the etched first dielectric layer and the second dielectric layer. Sequentially, the trenches are filled by a second metal layer. Finally, the second metal layer is planarized to expose surface of said second dielectric layer.
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