| 摘要 |
A method for forming a MIM(metal insulator metal) capacitor of an image sensor is provided to improve the yield and reliability of an image sensor by reducing occurrence of defects in forming an analog capacitor of the image sensor. A first metal layer, a dielectric layer(506a), a second metal layer, and an etch stop layer(508a) are sequentially formed on a conductive layer such that the dielectric layer includes a nitride layer. The etch stop layer is selectively etched to form a second electrode type of a capacitor. By using the etch stop layer as an etch mask, the second metal layer is etched to form a second electrode of a capacitor. An insulation layer for a hard mask(510a) is formed on the second electrode, including an oxide layer or a nitride layer. A photoresist pattern for defining a first electrode type of a capacitor is formed on the insulation layer for the hard mask, having a greater width than that of the second electrode. By using the photoresist pattern as an etch mask, the insulation layer for the hard mask and the dielectric layer are etched to form a dual hard mask having a stack structure composed of the hard mask and the dielectric layer. The photoresist pattern is removed. By using the dual hard mask as an etch mask, the first metal layer is etched to form a first electrode of a capacitor.
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