SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

In IC chips for display device driving, an operational amplifier is widely used in input and output circuits, and a capacitor in a medium withstanding voltage chip is used as a compensation capacitor. As for this product area, cost competitiveness is very important. Therefore, a MIS capacitor with good area efficiency is widely used. However, unlike a so-called varactor widely used in a VCO circuit, a characteristic of as small a voltage dependence of the capacitor as possible is used. Therefore, an additional process is added to reduce the voltage dependence of the capacitor, but there is a problem of an increase in process cost. A semiconductor substrate side capacitor electrode in a MIS capacitor within a first conduction type medium withstanding voltage chip used in an I/O circuit or the like on a semiconductor integrated circuit device is formed in a first conduction type low withstanding voltage well region.