| 摘要 |
PURPOSE:To provide a fine connecting hole with good reproducibility, by depositing an Si3N4 layer on a PSG layer by plasma CVD to form an interlayer insulation film and by forming apertures in the Si3N4 layer and in the PSG layer by isotropic etching and by RIE, respectively. CONSTITUTION:A PSG layer is provided on an Si substrate 21 having a diffusion layer 22. An Si3N4 layer 24 is deposited thereon by plasma CVD and a resist layer 25 is applied thereon so as to have a hole 27 with a width W0. The Si3N4 24 is plasma etched isotropically with the use of mixture gas of CF4 and O2 so as to form an aperture 28, whereby the side etched regions 29 are produced. Subsequently, the PSG23 is subjected to RIE so as to form an approximately vertical aperture 30, which has a width W2 equal to the width W0 of the aperture in the resist. Therefore, the connecting hole is constituted by the tapered Si3N4 film 28 and the PSG30 having vertical side walls. A metallic wire 32 is provided after removing the resist. According to this method, a fine connecting hole can be formed with good reproducibility and the metallic wire is not disconnected at the connecting portions. Thus a highly integrated device can be obtained. |
