High-Voltage Power Supply for Excimer Lasers: Optical Synchronous Trigger Technology

1. Significance of Synchronous Triggering in Excimer Laser Systems
Excimer lasers (e.g., ArF, KrF) are high-power pulsed light sources in the deep ultraviolet spectrum, indispensable in semiconductor lithography, micro-machining, and medical applications. Their excitation requires gas ionization and population inversion within nanoseconds. In master oscillator power amplifier (MOPA) systems, synchronization deviations exceeding 10 ns between stages can cause >15% energy loss and spectral broadening. Traditional electrical triggers struggle with multi-module timing alignment due to cable capacitance and electromagnetic interference (EMI). Optical synchronous triggering reduces timing jitter to ±2 ns by transmitting signals via fiber optics, ensuring phase matching between seed injection and power amplification. 
2. Core Mechanism of Optical Synchronous Triggering
The system comprises a central control unit, fiber-optic network, and opto-electronic conversion modules: 
• Central Control Unit: Generates reference optical pulse-width signals and charging voltage commands, distributed synchronously via fiber. 
• Fiber Transmission: Utilizes EMI immunity to isolate kV-level discharge spikes. 
• Opto-electronic Conversion: Converts optical signals to electrical pulses driving IGBTs or magnetic compression circuits. 
Closed-loop feedback via fiber reduces voltage sampling errors and achieves 5 ns timing precision. 
3. Key Technological Breakthroughs
1. All-Solid-State Magnetic Pulse Compression (MPC) 
   Replaces hydrogen thyratrons with IGBTs and multi-stage magnetic switches: 
   • IGBTs generate μs-level high-voltage pulses (10–20 kV). 
   • Magnetic switches compress pulse width to <100 ns and edges to 50–80 ns. 
   This extends switch lifespan to >10⁹ cycles and supports kHz-level operation at >90% efficiency. 
2. Resonant Charging and Topology Optimization 
   • LC Resonant Networks: Precisely control charging current to minimize voltage overshoot. 
   • Cascaded Marx Circuits: Combine modules for high voltage with stable amplitude. 
   • Common-Mode Chokes: Suppress interference, ensuring >60 dB signal-to-noise ratio. 
3. Pre-Ionization Synchronization 
   Aligns pulse edges with pre-ionization timing: 
   • Corona pre-ionization initiates 5–50 ns before main discharge, creating uniform electron clouds. 
   • Fiber-triggered pre-ionization prevents electrode erosion caused by arcing. 
4. Stability Enhancement Technologies
1. Energy Feedback Control 
   Monitors laser pulse energy in real-time, dynamically adjusting charging voltage via FPGA to limit energy fluctuations to ±0.8% (vs. ±5% conventionally). 
2. Extended Gas Lifetime 
   Uniform discharge reduces halogen consumption. Combined with real-time gas monitoring and optical replenishment, gas replacement intervals extend to 15 days (5× improvement). 
5. Applications and Future Trends
• Lithography: Enables 0.1 nm overlay accuracy in 6 kHz ArF light sources. 
• Medical Surgery: Limits energy fluctuations to <1% in corneal procedures, minimizing surface roughness. 
• Industrial Processing: Achieves SiC surface roughness <4.11 nm via nanosecond-level uniform discharge. 
Future advancements include: 
1. Integrated Smart Control: AI algorithms dynamically optimize pulse slopes for gas aging. 
2. Ultrafast Magnetic Materials: Nanocrystalline cores compressing pulses to 20 ns for next-gen EUV lithography. 
Conclusion
Optical synchronous triggering resolves timing precision and noise challenges in excimer laser high-voltage power supplies through opto-electronic isolation, solid-state MPC, and closed-loop control. With advancements in wide-bandgap semiconductors and AI algorithms, this technology will propel excimer lasers toward ultrafast, ultra-stable, and intelligent operation, underpinning high-end manufacturing and precision medicine.