| 摘要 |
PROBLEM TO BE SOLVED: To determine the polishing end point of a chemical-mechanical polishing process by forming, on a first layer of a wafer, a second layer which is made of a material whose polishing/removing speed is different from those of a material of which the first layer is made, and continuously measuring the electrical resistance of a slurry produced during the polishing of the second layer. SOLUTION: A wafer has a metallic layer 22 such as an Al layer formed on a substrate 20, and a dielectric layer 24 such as an oxide layer formed on the layer 22. Then, openings 26a, 26b and 28 are formed, and a metallic layer 30 such as a Cu layer is formed on the layer 24, while filling in the openings 26a, 26b and 28. Using the layer 24 as a polishing stop layer, the layer 30 is chemically-mechanically polished to form metallic plugs 32a and 32b within the openings 26a, 26b and 28. The layer 30 is abutted to a polishing pad 40, and the pad 40 is rotated. During polishing, a slurry is supplied in a manner to circulate between the polishing pad and the wafer. Since the end point of the polishing process coincides with the instance at which the layer 24 is exposed and at which the amount of metal ions dissolved in the slurry is reduced during the process, the end point is determined by measuring the electrical resistance value of the slurry. |
