| 摘要 |
PURPOSE:To eliminate voids in aluminum wirings by thermally decomposing a polymer formed in a through hole to remove it, thereby always reducing a contacting resistance. CONSTITUTION:After a predetermined Locos oxide film, a gate oxide film, a polysilicon gate, and a source.drain diffused layer are formed and processed on a silicon substrate 1, a PSG film 2 is formed, and lower layer aluminum wirings 3 are then formed. Then, an interlayer insulating film made of a PSG film 4 between upper and lower layer wirings is formed. When the film 4 is dry etched to open a through hole 6, a polymer 7 is deposited on the wirings 3 in the through hole 6. After the through hole is opened, a photoresist 5 due to O2 plasma is removed, and cleaned with fuming nitric acid. Subsequently, when a heat treatment is executed, for example, in N2 and H2 mixture gas atmosphere, the polymer is thermally decomposed, and completely removed to form upper layer aluminum wirings 8.
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