Method for forming an integrated circuit

A method for forming a contact structure, the method comprising the steps of:

• forming a first conductive layer overlying a semiconductor substrate;
• forming a first dielectric layer overlying the first conductive layer;
• forming a resist layer over the dielectric layer;
• patterning the resist layer to form an opening that exposes portions of the dielectric layer;
• placing the semiconductor substrate into a reactive ion etching chamber and in-situ processing the semiconductor substrate as follows:
• etching portions of the dielectric layer using a gas mixture that includes a fluorocarbon source gas to form an opening in the first dielectric layer, the opening having a bottom portion and sidewall portions;
• etching portions of the resist layer using a gas mixture that includes a fluorocarbon source gas and an oxygen source gas to remove portions of the resist layer and expose only top surface portions of the dielectric layer adjacent the sidewall portions;
• etching top surface portions of the dielectric layer adjacent the sidewall portions to taper the opening, wherein the taper has a a bottom portion and top portion wherein the bottom portion is closer to the conductive layer than the top portion, the top portion having a radius Y and the bottom portion of the opening having a radius X wherein X<Y;
• and
• removing remaining portions of the resist layer;
• depositing a conductive material into the opening;
• and
• polishing away a top portion of the conductive material and a top portion of the first dielectric layer to remove the taper.