| 摘要 |
<p>PURPOSE: To form a noise filter which is high in capacitance or in electrostatic strength by a method wherein the internal capacitance of the noise filter is determined by the sum of a distributed capacitance formed between a first metal wiring and a second metal wiring and another distributed capacitance formed between a semiconductor board and the first metal wiring. CONSTITUTION: A distributed constant-type low-pass filter is composed of a distributed capacitance 15 formed between a first metal wiring 3 and a second metal wiring 5, another distributed capacitance 16 formed between a semiconductor board and the first metal wiring 3, and the inductance of the first metal wiring 3 and the second metal wiring 5 both formed in spirals. The internal capacitance of the low-pass filter is determined by the sum of the distributed capacitance 15 and 16, whereby a noise filter of high capacitance can be formed without being increased in cost. An external static electricity is separately absorbed in the distributed capacitance 15 and 16, whereby the noise filter of this constitution can be improved in electrostatic strength.</p> |
