Techniques herein provide a chamber and substrate cleaning solution for etching and removing byproducts between separate etching steps. Such techniques include using a cleaning step based on fluorine chemistry, which is executed in between separate etch steps or divided etch steps. Such a technique can be executed in situ for improved efficiency. Other benefits include increasing etching depth/aspect ratios, and preventing post-etching defects including physical contact with neighboring gates, etc. Techniques herein are especially beneficial when applied to relatively small feature openings.