Selective Metal Fluoride Dry Etching Without Plasma Damage

The patent replaces the plasma-based chemical reaction system with a thermal field-based system. Instead of using plasma excitation to activate etching gas, the invention uses heated treatment gas (containing fluorine-containing interhalogen compounds) to directly react with metal films at controlled temperatures (50-200°C), thereby eliminating the need for expensive plasma generation equipment while achieving precise etching.

The patent changes the key parameter from plasma temperature (typically >1000°C) to controlled thermal reaction temperature (50-200°C). By using fluorine-containing interhalogen compounds that react at lower temperatures, the invention achieves effective metal etching without requiring high-cost plasma generation systems, thus resolving the contradiction between etching precision and manufacturing cost.

The patent introduces fluorine-containing interhalogen compounds (such as ClF3, BrF5, IF7) as intermediary substances that selectively react with metal films. These compounds serve as the active etching species, allowing precise control over which materials are etched. The treatment gas containing these compounds selectively removes metal films while leaving semiconductor substrates and insulating films intact, thereby achieving high selectivity without the high costs associated with plasma methods.

The patent employs an inert or controlled atmosphere using treatment gas containing fluorine-containing interhalogen compounds to prevent unwanted side reactions. This controlled chemical environment ensures that only the intended metal films are etched through selective chemical reactions, while protecting other semiconductor components from damage, thus maintaining high etching selectivity at lower manufacturing costs.