| 摘要 |
PURPOSE: A method for forming an air gap in a process for fabricating a semiconductor metal line is provided to embody low capacitance by using a conventional material, and to efficiently improve an RC delay by forming a stable air gap. CONSTITUTION: After a lower metal interconnection(202) is formed on a lower insulation layer(200), an upper insulation layer is stacked on the lower metal interconnection. After the first photoresist layer is patterned on the upper insulation layer, the upper insulation layer is etched until the lower metal interconnection is exposed. The first photoresist layer is removed. A nitride layer is filled in the etched upper insulation layer, and the upper insulation layer is eliminated. After the second photoresist layer is patterned on the nitride layer from which the upper insulation layer is removed, the lower metal interconnection is etched until the lower insulation layer is exposed. The second photoresist layer is eliminated. An IMD(intermetal dielectric) layer(212) is deposited to form an air gap(214). After the IMD layer is planarized by a CMP(chemical mechanical polishing) process, the nitride layer is eliminated by a wet etch process. After a conductive material(215) for a contact plug is filled in a hole from which the nitride layer is removed, an upper metal interconnection(216) is deposited.
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