Opto-Electrical Synchronization System for Excimer Laser High-Voltage Power Supply

Excimer lasers, characterized by short wavelengths (193nm/248nm) and pulse widths (1-10ns), are widely used in photoresist etching and material surface modification. Their HVPS needs to provide 20-50kV pulsed excitation voltage for the laser cavity. However, opto-electrical synchronization deviation can cause over 8% fluctuation in laser energy, directly affecting processing precision.
The synchronization system adopts an "FPGA-based main control + high-speed signal chain" architecture: On the optical side, an avalanche photodiode (APD) collects laser pulse signals, which are transmitted with a delay of <4.2ns after passing through a low-noise amplification circuit. On the electrical side, an insulated gate bipolar transistor (IGBT) driving module is used, with a switching response time <8ns. Impedance matching (50Ω±1%) of coaxial cables reduces signal reflection. The core synchronization algorithm realizes ns-level timing calibration based on a time-to-digital converter (TDC), locking the phase difference between the optical trigger signal and the electrical high-voltage pulse within ±2.8ns.
In excimer laser photoresist etching applications, this system improves laser energy stability from ±5% to ±1.8% and reduces linewidth uniformity deviation from ±4.5% to ±1.9%. In metal surface micro-structure processing, after the synchronization precision is improved, the etching depth consistency error is reduced from 6μm to 1.1μm, meeting the strict timing coordination requirements of high-precision laser processing.