High-Voltage Power Supply Process Gas Adaptation Technology in Etching Equipment

In semiconductor dry etching processes, the chemical properties of process gases and the energy regulation capabilities of high-voltage power supplies jointly determine etching precision and efficiency. Process gases generate active species (e.g., radicals, ions) through ionization, while high-voltage power supplies control plasma density and ion energy distribution via electric fields. The synergy between the two is central to achieving atomic-scale pattern transfer. 
I. Gas-Specific Power Parameter Requirements
1. Fluorine-Based Gases (e.g., CF₄, SF₆) 
   • Adaptation Requirements: High ion energy (>500 eV) to enhance physical bombardment and promote volatile byproduct formation (e.g., SiF₄ from Si or SiO₂). 
   • Power Design: High-frequency pulse modulation (>100 kHz) suppresses byproduct deposition. For silicon etching with SF₆, bias power must be dynamically adjusted (100–250 W) to balance etch rates and mask carbonization. 
2. Chlorine/Bromine-Based Gases (e.g., Cl₂, BCl₃) 
   • Adaptation Requirements: Focus on chemical corrosion, requiring low ion energy (<100 eV) to maintain high selectivity (e.g., Al₂O₃/photoresist >10:1 in aluminum etching). 
   • Power Design: Low-frequency bias (1–2 MHz) reduces ion kinetic energy, combined with closed-loop impedance matching to compensate for plasma impedance drift caused by gas flow fluctuations. 
3. Mixed Gases (e.g., CHF₃/O₂, CF₄/H₂) 
   • Adaptation Requirements: Balance physical sputtering and chemical reactions. For SiO₂ etching with CHF₃/O₂, O₂ flow ratio must be precisely controlled (optimal 0.5); excess O₂ depletes F radicals, reducing rates by 30%. 
   • Power Design: Dual-frequency drive (high-frequency 60 MHz + low-frequency 2 MHz) to excite radical density and direct ion bombardment. 
II. Core Adaptation Technologies for High-Voltage Power Supplies
1. Dynamic Impedance Matching 
   Gas composition changes (e.g., switching from CF₄ to C₄F₈) cause abrupt plasma impedance shifts (±40%). Power supplies must monitor reflected power in real time and adjust matching network capacitance/inductance to maintain >95% energy transfer efficiency. 
2. Customized Pulse Waveforms 
   • Square Pulses: Suitable for F-based gases; nanosecond pulse widths (50–200 ns) narrow ion energy distribution (ΔEi<5 eV), minimizing sidewall erosion. 
   • Ramp Pulses: Used for Cl₂-based gases; gradually increasing voltage prevents over-sputtering and substrate damage. 
3. Temperature Co-Control 
   Gas reaction kinetics are temperature-sensitive. For etching NdFeB, wafer temperatures must be held below 45°C. Power supplies integrate thermocouples and PID algorithms to dynamically adjust coolant flow, preventing thermal damage. 
III. Emerging Trends: Intelligent Gas-Power Synergy Systems
1. AI-Driven Parameter Optimization 
   Machine learning models trained on plasma optical emission spectroscopy (OES) data (e.g., CF₂⁺ at 483 nm and SiF₄ at 350 nm) predict optimal power-gas ratios in real time. 
2. Quantum Computing-Assisted Simulation 
   Multiphysics models simulate gas dissociation and ion transport under varying power parameters, predicting byproduct thresholds (e.g., CO deposition rates) to guide waveform design. 
Conclusion
Process gas and high-voltage power supply adaptation hinges on the precise coupling of chemical reaction pathways and electrical energy delivery. Future advancements will integrate wide-bandgap semiconductor devices (e.g., SiC MOSFETs) with adaptive algorithms, enabling atomic-scale synergy among gases, power supplies, and materials to advance etching processes for 3D NAND and sub-2nm nodes.