This plan primarily targets metal contaminant removal and surface cleaning needs in semiconductor manufacturing, with the following implementation details and advantages:

Alternative implementation plan for HF/O₃ mixed solution

1. Process Flow Design

Pre-treatment Stage: Ozone water (O₃/H₂O) is used for pre-cleaning. Leveraging ozone’s strong oxidizing properties, it decomposes organic residues (e.g., photoresist) while inhibiting excessive etching of the silicon surface by subsequent HF.

Main Cleaning Stage:

•HF Concentration Control: The HF proportion is typically 1:5–1:10 (HF:H₂O), with pH adjusted to 1.5–2.5 to avoid excessive etching of the silicon surface (Ra < 0.05 nm).

•O₃ Synergistic Action: O₃ concentration is maintained at 5–10 ppm. Through oxidation, it converts metal ions (e.g., Cu²⁺, Fe³⁺) into high-valent complexes (e.g., [Cu(OH)₃]⁻), enhancing their solubility.

•Dynamic Mixing: A jet reactor is employed to ensure uniform mixing of HF and O₃, with reaction time controlled within 3–5 minutes.

2.Key Parameter Optimization

•Temperature: 25–35°C (to avoid accelerating O₃ decomposition or HF volatilization at high temperatures).

•Pressure: Atmospheric pressure or slight negative pressure (to prevent O₃ leakage).

•Additives: Surfactants (e.g., sodium dodecylbenzenesulfonate) are introduced to reduce surface tension and improve the adsorption efficiency of metal contaminants.

3.Post-treatment Steps

•Neutralization and Rinsing: Residual HF is neutralized using NH₄OH/H₂O₂ to avoid acidic residue on the silicon surface.

•Drying Process: Supercritical CO₂ drying or nitrogen purging is applied to prevent water mark residue.

Core Advantages of Replacing SC-2 with HF/O₃ Mixture

1.Enhanced Removal Efficiency of Metal Contaminants

•Synergistic Oxidation and Complexation: O₃ oxidizes metals to high-valence states, while HF promotes metal dissolution via complexation (e.g., SiF₆²⁻). This achieves >99.5% removal rates for metals like Cu and Fe (compared to 95–98% for SC-2).

•Reduced Cl⁻ Residue: Avoids Cl⁻ erosion of high-k metal gates (HKMG) inherent in SC-2, lowering the risk of device leakage.

2.Superior Surface Roughness Control

•Low-Damage Characteristics: The HF/O₃ reaction produces SiF₆²⁻ and H₂O, eliminating point corrosion of the silicon surface caused by HCl in SC-2. Ra can be controlled below 0.03 nm (vs. 0.05–0.1 nm for SC-2).

•Suitability for Advanced Nodes: Meets stringent surface flatness requirements for sub-3nm processes.