Abstract: A multi-step plasma etch method for etching a tapered via having uniform bottom diameter ("CD") and extending through the resist and into the oxide layer of a coated semiconductor substrate, and a coated semiconductor substrate whose coating has been plasma etched to define such a tapered via. The first step of the inventive method is an anisotropic oxide plasma etch operation, preferably employing a plasma consisting primarily of CF.sub.4, which produces a non-tapered via having diameter substantially equal to CD and extending through the resist and into the oxide layer. A preferred embodiment of the inventive method includes a second step defining an upper sloping via portion without significantly increasing the diameter of a lower portion of the non-tapered via. This second step is a tapered resist plasma etch operation employing a mixture of oxygen (O.sub.2) and CF.sub.4. The slope of the upper sloping via portion may be controlled by varying the ratio of oxygen to CF.sub.4.