Cymer, LLC

A radiation source includes a chamber, a window, and a conduit system. The chamber confines a gas and contaminants produced during the generation of radiation. The window isolates the gas from an environment external to the chamber and allows the radiation to travel between the gas chamber and the environment. The refill path allows a replacement of the gas. The conduit system directs a flow of one of a refill gas, the gas, or the refill gas and the gas at least during a refill operation to prevent the contaminant from contacting the window. The conduit system may include one or more unidirectional valves which may be magnetic check valves. A magnet component of the magnetic check valve may be disposed external to the conduit and the chamber so that the magnet component is not subjected to corrosion by the gas in the conduit or the chamber.

A method for improving a lithographic process of imaging a portion of a design layout onto a substrate using a lithographic apparatus. The method includes computing a multi-variable cost function that is a function of: (i) a plurality of design variables that affect characteristics of the lithographic process and (ii) a radiation bandwidth of a radiation source of the lithographic apparatus; and reconfiguring one or more of the characteristics (e.g., EPE, image contrast, resist, etc.) of the lithographic process by adjusting one or more of the design variables (e.g., source, mask layout, bandwidth, etc.) until a termination condition is satisfied. The termination condition includes a speckle characteristic (e.g., a speckle contrast) maintained within a speckle specification associated with the radiation source and also maintaining an image contrast associated with the lithographic process within a desired range. The speckle characteristic being a function of the radiation bandwidth.

In some general aspects, a light beam control apparatus includes: a spectral feature actuator associated with a set of different states, each state configured to cause an optical apparatus to generate one or more pulses of a light beam at a discrete value of a spectral feature of the light beam; and a controller in communication with the spectral feature actuator. The controller includes: an actuator drive module configured to cause the spectral feature actuator to transition among the set of different states according to a control waveform; a waveform module configured to compute the control waveform for the spectral feature actuator that governs the transition among the set of discrete values; and a predictive module configured to receive one or more sensed aspects of the spectral feature actuator and instruct the waveform module to adjust the control waveform based on the received sensed aspects.

A light source apparatus ( 200 ) includes a gas discharge stage ( 210 ) and a metal fluoride trap ( 300 ). The gas discharge stage includes an optical amplifier ( 206 ) and a set of optical elements ( 250, 260 ). The optical amplifier includes a chamber ( 211 ) configured to hold a gas discharge medium ( 213 ), the gas discharge medium outputting a light beam. The set of optical elements is configured to form an optical resonator around the optical amplifier. The metal fluoride trap is configured to trap metal fluoride dust generated from the gas discharge stage. The metal fluoride trap includes an electrostatic precipitator ( 320 ) and a packed-bed filter ( 400, 402, 404 ) disposed around the electrostatic precipitator. The packed-bed filter includes a plurality of beads configured ( 406, 408 ) to absorb metal fluoride dust ( 208 ).

Disclosed is an apparatus for and method of permitting automatic alignment of optical components in the beam path of a laser. Images of the beam are obtained at one or more positions in the beam path. Alignment and possibly other information is derived from the images and then actuators are controlled to alter the alignment of the optical components in the beam path based on the derived information.

Apparatus for and method of generating multiple laser beams using multiple laser chambers. The relative timing of the beams is controllable so they may, for example, be interleaved, may overlap, or be prevented from overlapping, or may occur in rapid sequence. The beams may have different spectral and power characteristics such as different wavelengths. Also disclosed is a system in which at least one of the multiple laser chambers is configured to generate radiation of two different wavelengths.

Apparatus for and methods of rapidly achieving a target peak wavelength separation in a system for producing laser radiation at more than one wavelength in which one or more actuators control wavelength in response to being supplied with a waveform. The characteristics of the waveform are determined using a model reference control system.

A metrology apparatus includes: a probe apparatus configured to produce a probe in a vicinity of an optical element that is in fluid communication with a gain medium of a gas discharge chamber and is exposed to one or more dust particles; a detection apparatus configured to detect an interaction between the probe and one or more dust particles, and to produce an output signal based on the detected interaction; and a processing apparatus configured to receive the output signal and to estimate a property of the one or more dust particles.

A method is performed for scheduling a calibration relating to an optical device in a light source. The method can be performed by a calibration system including a calibration apparatus and a prediction controller. The method includes: receiving a property associated with the optical device while the optical device is being calibrated; calculating a current degradation metric based at least on the optical device property, the degradation metric modeling behavior of the optical device; estimating when a degradation of the optical device would exceed a threshold based on the current degradation metric; and scheduling a calibration of the optical device based at least in part on the estimate of optical device degradation.

A radiation system for controlling pulses of radiation comprising an optical element configured to interact with the pulses of radiation to control a characteristic of the pulses of radiation, an actuator configured to actuate the optical element according to a control signal received from a controller, the control signal at least partially depending on a reference pulse repetition rate of the radiation system and, a processor configured to receive pulse information from the controller and use the pulse information to determine an adjustment to the control signal. The radiation system may be used to improve an accuracy of a lithographic apparatus operating in a multi-focal imaging mode.