| 摘要 |
PROBLEM TO BE SOLVED: To dissolve an IC from operating unstably due to noises induced inside it and improved in electrostatic breakdown strength by a method, wherein capacitors of various kinds are formed stacked up in a power supply line region. SOLUTION: When a positive power supply voltage is given to a wiring 3 and a grounding voltage is applied to a wiring 5, an upper conductive layer 4 and a lower conductive layer 6 are each kept at a positive power supply voltage and a grounding voltage respectively. As a result, a capacitor C11 is composed of the upper conductive layer 4 and the lower conductive layer 6 and functions as a by-pass capacitor, between the power supply voltage wiring 3 and the grounding voltage wiring 5. A thin oxide film 2, interposed between the semiconductor substrate 1 and the lower conductive layer 6, is made to serve as a capacitor insulating film, and a capacitor C12 is formed between the semiconductor substrate 1 and the lower conductive layer 6. The capacitor C12 also functions as a by-pass capacitor between the power supply voltage wiring 3 and the grounding voltage wiring 5. In this way, capacitors of various types are formed stacking up, whereby noises emitted from a digital circuit can be restrained.
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