The present invention discloses a method of forming a contact hole of the semiconductor device to stabilize the contact resistance. The method of the present invention is disclosed, comprising: providing a semiconductor substrate having a given infrastructure; Forming a photoresist pattern on the semiconductor substrate defining a lower metal wiring of aluminum film, TiN film and a SiON film, a HSQ film, the oxide film and the contact hole forming regions containing a silicon component in turn; The method comprising using the photoresist pattern as an etch barrier and etching the SiON film is used as the etch stop layer is the silicon-containing oxide component and the HSQ film; A step of etching the SiON film to form a contact hole to the point at which the TiN film is exposed by using the photoresist pattern as an etch barrier; Removing said photoresist pattern; And a step of depositing a Ti film on the resultant including the contact hole.