The present invention relates to a method of fabricating a MIM structure capacitor. The method includes sequentially depositing a nitride film, a Ti film, and a TiN film over a lower electrode metal layer, the nitride film being an insulating layer, and a combination of the Ti/TiN layers being a upper metal electrode, for the MIM structure capacitor. The method further includes coating a photoresist layer on the upper electrode metal layer and patterning the photoresist layer, then selectively etching the upper metal electrode layer, and the nitride film by using the patterned photoresist layer as an etch mask, and finally removing nitride remaining on sidewalls of the MIM structure capacitor through a wet cleaning process.