| 摘要 |
PURPOSE:To reduce the stray capacitance of a crossing part of wiring in a multilayer interconnection structure having a flattened interlayer insulating film, by forming a recessed part in the base substrate of a lower wiring of the crossing part. CONSTITUTION:An interlayer insulating film 3 between a lower wiring layer 1 being a first layer wiring and an upper wiring layer 2 being a second layer wiring is flattened. At a crossing part of the first layer wiring and the second layer wiring, a recessed part 5 is formed in a semi-insulating semiconductor substrate 4 being a base substrate of the first layer wiring. The thickness of the interlayer insulating film on the lower layer wiring 1 is h2, and the upper surface of the lower wiring layer 1 becomes lower by the depth h3 of the recessed part 5. On the other hand, as the surface of the interlayer insulating film is flat, the thickness h4 of the interlayer insulating film at the crossing part becomes h2+h3. Therefor, the thickness is increased by h3, as compared with the usual structure, and the stray capacitance is decreased by that amount. Accordingly, a large stray capacitance does not generate at the crossing part of wirings.
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