| 摘要 |
A method for planarizing an integrated circuit. The integrated circuit is to be planarized to an upper surface using chemical mechanical polishing. The upper surface of the integrated circuit includes regions of a first material and regions of a second material. The first material has a first polishing rate and desired chemical, physical, and electrical properties. The second material has a second polishing rate and desired chemical, physical, and electrical properties. The first polishing rate is greater than the second polishing rate. The regions of the first material adjoin the regions of the second material at interfaces. The upper surface of the integrated circuit is overlaid with a top layer of the second material, that is to be removed by the chemical mechanical polishing. Both the regions of the second material and the top layer of the second material are deposited during a deposition. The upper surface of the integrated circuit tends to form deleterious tapers at the interfaces between the first material and the second material when the chemical mechanical polishing is taken past a desired end point. The improvement comprises modifying the second material to increase the second polishing rate by adding a dopant to the second material prior to planarizing the integrated circuit. The dopant does not significantly adversely affect either the desired chemical, physical, and electrical properties of the second material, or the desired chemical, physical, and electrical properties of the first material. Thus, by modifying the second polishing rate of the second material, the difference in polishing rates between the first material and the second material is reduced, and the deleterious tapers in the top surface, which are caused at least in part by over polishing a surface that has regions of different materials that have different polishing rates, tend to be eliminated or dramatically reduced, depending at least in part upon how closely the second polishing rate is matched to the first polishing rate by the modification of the second material.
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