SEMICONDUCTOR DEVICE AND ITS MANUFACTURE

PROBLEM TO BE SOLVED: To improve the reliability of a semiconductor device having a wiring layer by preventing an SOG(spin-on-glass) film from making contact with the wiring layer when the device is planarized by using the SOG film. SOLUTION: A plasma oxide film 9 is formed on an aluminum wiring layer 8, which is a lower layer wiring layer, and the film and the layer are both patterned. Then, the stacked film is covered with a plasma oxide film 10. After forming an SOG film 11, dry etching is performed, the SOG film 11 and the plasma oxide film 10 are completely removed from the upper layer of the aluminum wiring layer 8, and etching is performed until the lower layer plasma oxide film 9 has a prescribed film thickness. Thus, exposure of the SOG film 11 on the side plane of a via hole 13, which reaches the aluminum wiring layer 8, is suppressed, and an aluminum wiring layer 14 which fills the via hole 13 is prevented from making contact with the SOG film 11.