US 7,308,013 B2 · Excimer or molecular fluorine laser system with precision timing

Abstract

A Master Oscillator (MO)—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.

Claims13

Dependent claims

An excimer or molecular fluorine laser system, comprising:

first and second discharge chambers each being filled with a gas mixture, each of said first and second discharge chambers containing a pair of electrodes for energizing the gas mixture and outputting an optical pulse;
circuitry for providing separate, sequential excitation pulses to said first and second discharge chambers;
and
a real time jitter compensation circuit, said jitter compensation circuit receiving an input corresponding to a measured laser parameter which exhibits pulse to pulse variations, said jitter compensation circuit generating a variable delay signal in response to the received input and supplying the signal to said circuitry to control the relative timing of the excitation pulses delivered to the first and second discharge chambers on a real time pulse to pulse basis, and wherein said laser parameter is selected from one or more of the voltage on a storage capacitor, a reset current and a core magnetization.

1 more element

Dependencies are inferred from the claim text.

Excimer or molecular fluorine laser system with precision timing

Life of this patent

Excimer or molecular fluorine laser system with precision timing

Life of this patent

Abstract

Claims13