Enhancing step coverage by creating a tapered profile through three dimensional resist pull back

A new method of forming contact or via openings is achieved. A photoresist layer is formed and patterned top of layers of insulating materials overlying a semiconductor substrate. An isotropic etch is performed etching both vertically and horizontally a portion of the insulating layers. The photoresist is pulled back via a pure isotropic etch. Since the resist is being etched threedimensionally, an overhang resist profile is formed at the top of the opening. The opening is completed by anisotropically etching the remainder of the contact or via opening. The overhang part of the resist is recessed back gradually during etching. The oxide is exposed gradually through and together with the resist recessing back. The step formed after the first isotropic etch will be exposed to the anisotropic etch and will be etched into a slope.