Lambda Physik Ag

Coherent, Inc.

Lambada Physik Gmbh

Andreas Targsdorf

Rainer Desor

Sergei V Govorkov

Igor Bragin

Rainer Paetzel

Hubertus Von Bergmann

Spencer Merz

Dirk Basting

Andriy N Knysh

Two excimer lasers have individual pulsing circuits each including a storage capacitor which is charged and then discharged through a pulse transformer to generate an electrical pulse, which is delivered to the laser to generate a light pulse. The time between generation of the electrical pulse and creation of the light pulse is dependent on the charged voltage of the capacitor. The capacitors are charged while disconnected from each other. The generation of the electrical pulses is synchronized by connecting the capacitors together for a brief period after the capacitors are charged to equalize the charging voltages. The capacitors are disconnected from each other before they are discharged.

High-precision synchronization of pulsed gas-discharge lasers

A Master Oscillator (MO)&#x2014;Power Amplifier (PA) configuration (MOPA) can be used advantageously in an excimer laser system for micro-lithography applications, where semiconductor manufacturers demand powers of 40 W or more in order to support the throughput requirements of advanced lithography scanner systems. The timing of discharges in discharge chambers of the MO and PA can be precisely controlled using a common pulser to drive the respective chambers. The timing of the discharges further can be controlled through the timing of the pre-ionization in the chambers, or through control of the reset current in the final compression stages of the pulser. A common pulser, or separate pulser circuits, also can be actively controlled in time using a feedback loop, with precision timing being achieved through control of the pre-ionization in each individual discharge chamber. Yet another system provides for real-time compensation of time delay jitter of discharge pulses in the chambers.

Excimer or molecular fluorine laser system with precision timing

Precise timing control can be obtained for a gas discharge laser, such as an excimer or molecular fluorine laser, using a timed trigger ionization. Instead of using a standard approach to control the timing of the emission or amplification of an optical pulse using the discharge of the main electrodes, the timing of which can only be controlled to within about 10 ns, a trigger ionization pulse applied subsequent to the charging of the main electrodes can be used to control the timing of the discharge, thereby decreasing the timing variations to about 1 ns. Since ionization of the laser gas can consume relatively small amounts of energy, such a circuit can be based on a fast, high-voltage, solid state switch that is virtually free of jitter. Trigger ionization also can be used to synchronize the timing of dual chambers in a MOPA configuration. In one such approach, ionization trigger can include at least a portion of the optical pulse from the oscillator in a MOPA configuration.

Excimer or molecular fluorine laser with several discharge chambers

An isolation means used in conjunction with supplying energy to a laser, which isolates a power supply from the pulser circuit, and commutates a switch which activates the discharge of energy to the laser.

Magnetic switch controlled power supply isolator and thyristor commutating circuit

Magnetic switch controlled power supply isolator and thyristor

Growing community of inventors

Göttingen, Germany

Andreas Targsdorf