| 摘要 |
PURPOSE:To improve on an Al electrode in its throwing power by a method wherein a MOS transistor gate electrode is provided with a side wall of heat- softening oxide film. CONSTITUTION:A thermal oxide film 2 and polycrystalline silicon gate electrode 3 are built on a single-crystal silicon substrate 1. Next, a first heat-softening oxide film is formed of for example boron-phosphosilicate glass (BPSG), which is subjected to anisotropic etching for the formation of a side wall 8 on the gate electrode 3. A process follows wherein a second heat softening oxide film is formed, a BPSG layer 5 for example, whose unnecessary portion is then removed by photoetching for the formation of a contact hole 6. When the temperature is raised to approximately 1000 deg.C, the BPSG grows soft, and the BPSG layer 5 is flattened around the contact hole 6. An Al electrode 7 built after this process is rich in throwing power. In a device designed as such, there will be no electromigration-caused ill effects attributable to a disconnected or thinned-out Al electrode 7.
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