Dry layer removal mainly relies on reactive ion etching (RIE) equipment or mechanical grinding. Etching machines are mainly used to remove the passivation layer on the surface of chips and the oxide layer between layers. The passivation layer is mainly composed of silicon nitride and silicon oxide, with density and chemical stability, and is the outermost protective layer of the chip. Driven by an RF power source, the reactive gas is ionized to form a plasma. The free radicals in the plasma react with the etched material to generate volatile compounds, thereby achieving anisotropic etching of the passivation layer.

Mechanical grinding is the physical removal of materials and is suitable for scenarios that require large-scale removal or fine grinding of specific areas。