Profile evolution in the multilevel technique

The oxygen reactive ion etching of sub-half micron features in organic layers produces a variety of profile effects depending on both system parameters and pattern arrangements. Vertical and lateral etch rates of the bottom resist in a tri-level resist system were investigated with particular attention to the trench aspect ratio. In order to properly study the etch behaviour and to evaluate their various facets, a new version of the simulation program ADEPT (Advanced Simulation of Dry-Etching Process Technology) was developed. This now permits inclusion of physical and chemical descriptions of the etch process. Examples of profile phenomena observed in the tri-level technique are compared with corresponding output from the simulation program.