Patent ID: 7456440

Claim:
An electrostatic protection device for preventing breakdown of a protected circuit due to electrostatic discharge, comprising: a semiconductor substrate of a first conductivity type; a well of a second conductivity type formed on the semiconductor substrate; a first diffusion layer of the first conductivity type formed on the second conductivity type well and connected to a signal terminal; a first well of the first conductivity type formed on the semiconductor substrate; a first diffusion layer of the second conductivity type formed on the first well and connected to a ground terminal; a second well of the first conductivity type formed on the semiconductor substrate and spaced apart from the first well; and a second diffusion layer of the first conductivity type formed on the second well connected to a ground terminal, wherein a region between the first well and the second well is of the first conductivity type and has a lower impurity concentration than the first well and the second well.