摘要:
A preionization device for a gas laser comprises an internal preionization electrode having a dielectric housing around it and an external preionization electrode displaced from the dielectric housing by a small gap. The dielectric housing includes two cylindrical regions of differing outer radii of curvature. An open end of the housing has a larger radius of curvature than the other end which is closed. The internal electrode connects to circuitry external to the discharge chamber via a conductive feedthrough which penetrates through the housing. The external circuitry prevents voltage oscillations caused by residual energy stored as capacitance in the dielectric housing. The external preionization electrode, which is connected electrically to one of the main discharge electrodes, is formed to shield the internal preionization electrode from the other main discharge electrode to prevent arcing therebetween. The external electrode is also formed to shield the outer gas volume and walls of the discharge chamber from the preionization unit. A semi-transparent external electrode prevents charged particles emanating from the main discharge area from settling on the housing and causing field distortion and discharge instabilities.
摘要:
A preionization device for a gas laser comprises an internal preionization electrode having a dielectric housing around it and an external preionization electrode displaced from the dielectric housing by a small gap. The dielectric housing includes two cylindrical regions of differing outer radii of curvature. An open end of the housing has a larger radius of curvature than the other end which is closed. The internal electrode connects to circuitry external to the discharge chamber via a conductive feedthrough which penetrates through the housing. The external circuitry prevents voltage oscillations caused by residual energy stored as capacitance in the dielectric housing. The external preionization electrode, which is connected electrically to one of the main discharge electrodes, is formed to shield the internal preionization electrode from the other main discharge electrode to prevent arcing therebetween. The external electrode is also formed to shield the outer gas volume and walls of the discharge chamber from the preionization unit. A semi-transparent external electrode prevents charged particles emanating from the main discharge area from settling on the housing and causing field distortion and discharge instabilities.
摘要:
A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion. The curvatures of both main electrodes may conform to the curvature of the gas flow through the discharge chamber to further improve aerodynamic performance. A plurality of low inductive conducting ribs are connected to the grounded main electrode and shaped to provide a more uniform flow of gases through openings defined between adjacent ribs.
摘要:
A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion. The curvatures of both main electrodes may conform to the curvature of the gas flow through the discharge chamber to further improve aerodynamic performance. A plurality of low inductive conducting ribs are connected to the grounded main electrode and shaped to provide a more uniform flow of gases through openings defined between adjacent ribs.
摘要:
A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion. The curvatures of both main electrodes may conform to the curvature of the gas flow through the discharge chamber to further improve aerodynamic performance. A plurality of low inductive conducting ribs are connected to the grounded main electrode and shaped to provide a more uniform flow of gases through openings defined between adjacent ribs.
摘要:
A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion. The curvatures of both main electrodes may conform to the curvature of the gas flow through the discharge chamber to further improve aerodynamic performance. A plurality of low inductive conducting ribs are connected to the grounded main electrode and shaped to provide a more uniform flow of gases through openings defined between adjacent ribs.
摘要:
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.
摘要:
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.
摘要:
The lifetime of the laser gas in a laser system such as an excimer laser can be increased by changing the way in which the laser system is sealed. In addition to primary seals used to seal the reservoir chamber and discharge channel, at least one secondary seal can be used between the primary seals and the surrounding environment in order to further prevent permeation of impurities into the discharge chamber, as well as to create an intermediate gas volume. A controlled atmosphere can be generated in the intermediate gas volume, which can be at a slightly higher pressure than the surrounding environment in order to resist the flow of impurities through the secondary seal(s). Further, a flow of purge gas can be introduced into the controlled atmosphere in order to carry away any impurities that leak through the secondary seal(s).
摘要:
The consumption and/or erosion of electrodes in high repetition rate gas discharge lasers, such as excimer or molecular fluorine lasers, can be reduced using any of a number of temperature regulation approaches described herein. A flow of a cooling medium can be used to remove heat from the electrodes during laser operation, in order to reduce the rate of consumption and/or erosion. The rate of erosion can be controlled by adjusting the rate and/or temperature of the cooling medium flowing through the electrodes, or in bodies in good thermal contact with those electrodes. The cooled electrodes also can function to remove heat from the laser gas, and can have finned surfaces to facilitate such heat removal. Regulating the temperature of the electrodes and laser gas also can function to minimize resonance effects in the laser gas due to the presence of temperature gradients.