TW200908489A - Method and apparatus for stabilizing and tuning the bandwidth of laser light - Google Patents

Abstract

According to aspects of an embodiment of the disclosed subject matter, method and apparatus are disclose that ma y comprise adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, without utilizing any beam magnification control, or adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for other than bandwidth control, and adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for bandwidth control based on the error signal.

Description

200908489 IX. Description of the Invention: [Technical Field of the Invention] Field of the Invention The present disclosure relates to, for example, a DUV gas discharge laser system (for example, an excimer for, for example, a line narrowing application) Active control of the bandwidth within a fluorine molecular laser system, for example, as one of the integrated circuits fabricated by photolithography. BACKGROUND OF THE INVENTION 10 Stable bandwidth (e.g., E95 for DUV semiconductor integrated circuit lithography laser source design) includes passive and active bandwidth control. Active control allows these sources to benefit from optical performance correction ("OPC") and tool-to-tool matching of such sources. US Provisional Patent Application Serial No. 60/923,486, entitled "TWO STAGE EXCIMER LASER WITH SYSTEM FOR 15 BANDWIDTH CONTROL", filed on April 13, 2006, including U.S. Patent Application Serial No. 11/510,037 (Announcement of "ACTIVE SPECTRAL CONTROL OF DUV LIGHT SOURCE", filed on August 25, 2006, published on August 23, 2007, the disclosure of which is US-2007-0195836-A1, which claims the serial number Priority for the US Provisional Application No. 60/774, 770 20 (named "ACTIVE SPECTRAL CONTROL OF DUV LIGHT SOURCES FOR OPE MINIMIZATION", filed on February 17, 2006), each of these applications The disclosure is incorporated herein by reference. The application serial number 11/510,037 discloses a multi-level bandwidth control system that uses the coarse and fine control to activate the 200908489 device. The present application discloses various techniques for raster bending as an actuator (the position of the bandwidth-modifying device "BCD" that distort the grating) and the use of other actuators to stabilize this f-width. Active Bandwidth Control System 5 uses very accurate on-board spectrum measurements (eg, E^) and bandwidth error feedback. Compensation based on other laser parameters/output signals (eg, target energy and duty cycle) can enable control of various bandwidth selection actuators, including low frequency large value actuators and a high frequency small amplitude Actuator. - lithographic source laser (a multi-input multi-output (ΜΙΜΟ) nonlinear system with a time varying of 10) can use a (complex) actuator, except that the bandwidth is changed, the actuator itself may Laser performance causes other effects (expected or undesired). Multiple orders (e.g., two-step actuator designs) that have the effect of affecting laser behavior with individual operational parameter inputs (actuators) can be optimized to respond to a (plural) specific class of interference. Interference can be classified by the time scale and/or the size of the influence. Pulse energy settings can include low amplitude fast time-scale interference (typically milliseconds to seconds in a fine actuation range). The high duty cycle (in seconds) and the low (hour) frequency level of the duty cycle set point and fluorine gas consumption (in hours) can cause large amplitude effects. Other long-term parameter changes, component aging, and misalignment (day to week or 20 or even longer) can result in a change in maximum amplitude (in a coarse actuation range). Thus, control actions classified into coarse actuation and fine actuation are disclosed, each using one or more parameter varying actuators. Among them, the emphasis is on large-value low-frequency interference (large Em set point changes, gas aging effects and long-term changes in duty cycle (for example) from slow heat load changes, and laser elements of 200,908,489 The café has a focus on the higher amplitude and higher frequency interference (the fast pulse element of the output pulse energy changes in red, for example, from the faster thermal load transient and the like). The actuator can also be used to desaturate or reposition the center, the (complex) fine actuator is within its control range. _ coarse actuator (eg, helium gas injection) and fine actuator light thumb bending or other front wave consistent Adjustments can be made to the beam adjustment aperture or other mechanical display to adjust the bandwidth and used together for bandwidth control, with various effects on other laser parameters and the time frame of the measurement for feedback and allowing the deconstruction to act. Word 5 my dtMOPA Or ΔίΜ0ΡΑ or differential emission time or differential discharge timing or differential counting control (as used herein) is a simplified notation for the following concepts: at the source laser electrode and Discharge timing between the laser electrodes to selectively amplify a portion of the source laser pulse within the amplifier gain medium to select the bandwidth of the output of the laser source. Note 15 to require sufficient actuation range to Ability to address wide variations in these effects from general effects that are inhibited due to long-term duty cycle changes, gas aging, and component aging. Error signal changes (filtering and other normalization) due to other laser operating parameters Can be compensated/reduced sensitivity. The variable amplification of a 2 〇 beam incident on a central wavelength selective optic (eg, a dispersion grating) can also affect the bandwidth of the source. This system is in U.S. Patent No. 6,393,037 ( Issued on May 21, 2002

The contents of this patent are discussed in the 'Butting et al.' The Basting abstract describes a tunable laser comprising an angularly dispersive optical element (grating) and a beam expandable bandwidth of one or two of the 200908489 rotating prisms included in a line narrowing module. The plural expansion (when both are used) is revealed to be mechanically connected to each other, so that when the magnification changes, the person (four) of the light beam on the dispersing element is not changed. This configuration makes it very difficult, if not impossible, to use the rotary 稜鏡 control center, wavelength, and bandwidth. In addition to this, the bandwidth control (four) system is very difficult to use the two operations of the serial operation. It is believed that GlgaPh〇t〇n has released a product that uses some kind of optical actuation to perform Ε95 control. Japanese patent application 襄〇24855 (released on July 9th of the year) also revealed a variable magnification 1nm with two rotating prisms and will be between the source laser and the amplified laser. A differential discharge emission timing is used for bandwidth control. This configuration makes it difficult (if not impossible, then controlling money (4) length and bandwidth, and controlling the bandwidth in H may have some disadvantages. Figure 12 (taken from 〇37 application) describes the use ^MOPA&Bandwidth Control makes the differential emission time as a fine actuator control & bandwidth. There are advantages, including. (1) E95 measurement and △ [_ change can be about tens of pulse time scale or more Short occurrences, such as pulse-to-pulse, 允许 allow for non-directional frequency interference rejection; and (7) actuation of the available range, the attenuation/suppression is the source of the target's bandwidth offset, ie, the laser 20 energy and duty cycle Higher frequency effects of change. Existing types of active bandwidth control may have some disadvantages, such as using too long a period of time to recover from large disturbances (eg, transients after -flux injection) or changes in private bandwidth They may cause the bandwidth to leave the target as much as possible - 55 firing averages (for example) or (4) when 200,908,489 are summed with points). Return to the target Considering -55 examples of firing standard deviations, the target may take more than a few tens of seconds. In addition to this, correct money, (4) Qian Daqing, or from gamma = low to Cong _ Qian Da (10) seconds, when the request may be as low as about 10 seconds 0

In other respects, the error may be due to the control (four) ϋ L is generated - the controller step signal can be sent to - the bandwidth actuated stepper has just delayed too many pulses, so that the bandwidth can be sampled at a lower frequency. On the 10th cycle, there is a very high probability that the step command will not occur during a burst. Since the stepper command or the stepper itself can be enabled during a burst interval, the bursts within the bandwidth can be established on each other, and any correction signals are sent to (plural) Bandwidth control actuator. Conventional bandwidth stabilization control can set a 15 bandwidth control set point in a set and forgotten manner. The more stringent requirements require a tunable bandwidth setting that can be controlled by the end user of the laser source. Bandwidth control systems are also required to have no negative impact on other laser operations or control of output parameters, such as output pulse energy and dose stabilization and the like. The use of a variable aperture outside the laser cavity and the active bandwidth control of the other bandwidth controlled actuators proposed herein are advantageous over prior art techniques. The optical components in the cavity can be simplified and reduced in number, especially in a single chamber or in an amplifier with a multi-variable laser system with very high optical loads. The variable aperture in combination with other actuators can be a coarse adjuster or a fine adjuster for bandwidth control. SUMMARY OF THE INVENTION The present invention provides a method for controlling bandwidth within a laser system, the laser system comprising: 5 - a gas discharge source laser having a resonant cavity and producing a source laser Output; a gas discharge amplifier laser that amplifies the source laser output and produces a laser system output; a bandwidth metric unit that measures the bandwidth of the laser system output and provides a bandwidth measurement; and a bandwidth error signal a generator, receiving the bandwidth measurement value and a bandwidth set point and providing a bandwidth error signal; a variable amplification line narrowing unit located in the resonant cavity of the source laser, comprising a grating and a variable beam amplification An optical system; 15 a differential timing controller that selects a timing of a discharge between a pair of electrodes within the source laser and a pair of electrodes within the laser of the amplifier; the method comprising the steps of: The bandwidth is controlled by a bandwidth controller having three 20-mode amplification controls, wherein a first mode does not control the line narrow Amplifying the beam within the cell, a second mode driving the amplification of the beam within the line narrowing unit to a selected value independent of the bandwidth error signal, and a third mode driving the band based on the bandwidth error signal The amplification of the beam within the line narrowing unit; and 10 200908489, wherein in each mode, the differential timing controller selects the timing based on the bandwidth error signal or does not consider the bandwidth error signal. The invention provides a laser system comprising: a gas discharge seed source laser having a resonant cavity and generating a source lightning output; a gas discharge amplifier laser amplifying the source laser output and generating a laser a system metric unit, measuring a bandwidth of the output of the laser system and providing a bandwidth measurement value; and 10 a bandwidth error signal generator, receiving the bandwidth measurement value and a bandwidth set point and providing a bandwidth error signal; a variable amplification line narrowing unit, located in the resonant cavity of the source laser, comprising a grating and a variable beam amplifying optical system; a differential timing controller, selecting a different electrode in the source laser a timing of a discharge of a discharge between a pair of electrodes in the laser of the amplifier; a bandwidth controller having three modes of amplification control, the bandwidth controller not controlling the variable amplification line narrowing unit In a first mode, the bandwidth controller controls the variable amplification line narrowing unit to drive the amplification to a selected value that is independent of the bandwidth error signal. a second mode, and the bandwidth controller controls the variable amplification line narrowing unit to select a third mode of the bandwidth of the laser system output according to the bandwidth error signal; and wherein the differential timing controller is based The bandwidth error signal selects the timing or does not consider the bandwidth error signal. 11 200908489 The present invention provides a laser system comprising: a laser source comprising: a source laser defining an optical resonant cavity that produces an output; an amplifier laser that receives the laser output of the source and amplifies the species a source metric output module; a bandwidth metric module that measures a bandwidth of a laser output light pulse beam pulse generated by the light source and generates a bandwidth measurement value; a bandwidth error signal generator that receives the bandwidth measurement value and a bandwidth Setting a point and providing a bandwidth error signal; 10 a bandwidth selecting component external to the resonant cavity of the source laser, selecting a spatial portion of the beam to selectively vary the bandwidth of the source laser output. The present invention provides a laser system comprising: a source laser defining an optical resonant cavity that produces an output; 15 - an amplifier laser that receives and amplifies the output of the source laser and provides a laser system output; a bandwidth metric module for measuring a bandwidth of a laser output optical pulse beam generated by the light source and generating a bandwidth measurement value; a bandwidth error signal generator receiving the bandwidth measurement value and a bandwidth 20 set point and providing a bandwidth a bandwidth error signal; a differential timing system that echoes the bandwidth error signal to selectively adjust a differential transmission time between the source laser and the amplifier; and a beam adjustment system that is controllably adjusted a beam size of a beam within the resonant cavity of the source laser to selectively change the bandwidth of the source laser output and also controllably adjust the center wavelength of the source pulse; The beam sizing system comprises: a plurality of beam size adjustments; and 5 at least one other prism comprising a central wavelength selective prism. The present invention provides an apparatus comprising: a source laser defining an optical resonant cavity that produces an output; an amplifier laser that receives and amplifies the output of the source laser and provides a laser system output; a metric module that measures a bandwidth of a laser output optical pulse beam pulse generated by the light source and generates a bandwidth measurement value; a bandwidth error signal generator that receives the bandwidth measurement value and a bandwidth set point and provides a bandwidth error signal a differential timing system that echoes the bandwidth error signal to selectively adjust a differential emission time between the source laser and the amplifier; and a beam size adjustment system that controllably adjusts the source radar Generating a beam of a beam within the cavity to selectively vary the bandwidth of the source laser output and also controllably adjusting the center wavelength of the source pulse; and the beam resizing system comprises: 20 a beam size adjustment 稜鏡; a dispersive optical element; and a center wavelength selective prism at least partially defining the light on the dispersive optical element One angle of incidence; 13200908489 and a central wavelength selective mirror, cooperating with the other Prism, the dispersion is defined at least on the incident angle of the optical elements of the beam. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a bandwidth control device e95 sensitivity curve; 5 Figure 2 depicts the interference type and time scale and amplitude of the layer according to one embodiment of the disclosed subject matter; And a multi-level gas discharge laser system with a variable amplification line narrowing module and differential emission time (dtMOPA) bandwidth control according to the level of one embodiment of the disclosed subject matter is shown in block diagram form. Figure 4 is a schematic and block diagram showing an embodiment having four turns and a grating in accordance with a layer of one embodiment of the disclosed subject matter, wherein at least one turn can be rotated Increasing/reducing the beam width to change the bandwidth; 15 Figure 5 depicts the overall architecture of a laser control system that can be used at the level of one of the disclosed embodiments; Figure 6 is schematically and in block diagram form A representative laser system "implanted" in accordance with the level of one embodiment of the disclosed subject matter; FIG. 7 schematically and in block diagram form the level of an embodiment in accordance with the disclosed target 20 one of a wide controller; Figure 8 is a schematic and block diagram depicting a firing smoother in accordance with one level of an embodiment of the disclosed subject matter; Figure 9 is schematic and illustrated in block diagram form according to the disclosure One of the elements of the embodiment is a non-inductive hysteresis block; 25 Figure 10 is schematically and in block diagram form according to the disclosed standard 14 200908489; according to the disclosed target-center wavelength selection A control mode at a level of one embodiment selects an embodiment having a complex chirp and a mirror at the level of one embodiment of the embodiment illustrated schematically and in block diagram form; heart; - embodiment Figure 12 depicts a 13th diagram of E95 bandwidth control using Δϊμ〇ρα, which schematically depicts a variable amplification LNM in accordance with the level of the disclosed target; the second diagram is schematic and depicted in block diagram form An adjustable aperture bandwidth control actuator (control center) according to the disclosed embodiment of the standard 10; ° Figure 15 shows schematically and in block diagram form according to the disclosed subject matter One implementation An example of a bandwidth control system; and Figure 16 illustrates an example of a change in bandwidth dependent on the size of the aperture through which the beam passes. 15 Embodiments Detailed Description of Preferred Embodiments

The primary purpose of active bandwidth control in accordance with one embodiment of the disclosed subject matter is to control the Ε 带宽 bandwidth of the laser light 'using the same or similar (complex) input signal as the previously used active bandwidth control system, however with 20 different Signal processing and actuation mechanisms. Therefore, a tunable advanced bandwidth stabilization "eight 38," ("1^^5") is proposed to control the bandwidth to a target setpoint that can be used by a laser end user or a laser beam. Tool control system selection. Controlling bandwidth to ±50 fm or less (for constant pulse reception rate or other selected constant operating parameters) is proposed and has an error in bandwidth greater than 50 fm 15 25 200908489 'The system can Greater than or equal to 〇.〇〇〇3fm/Ray shots return to the set point. The center wavelength is not affected or minimally affected, while the bandwidth is controlled in a mode other than a target change mode (via <5 fm— Consider a 55-shot moving average wavelength value as an example - and <6 5 fm - consider a 55-striving movement standard deviation as an example, which is summed by integral.) A control > Bezhen method can be controlled using various bandwidth actuators The stepper is used for bandwidth selection (thick and thin), including a variable amplification line narrowing module ("VMLNM"), a bandwidth control module ("bWCM"), and a beam analysis module (" BAM") As discussed herein. 10 A measured Εκ signal is used to determine the adjustment of a Bandwidth Control Device (BCD) or the like, including the bandwidth used to deform the center wavelength selective grating to affect the output of the laser source. The mechanism of BCd is well known in the art. Bandwidth control can be achieved by maintaining a specific side of a BCD operating curve, such as to the right or left side of a BCD curve, as described in Figure 1. It is noted that the interference 80 can be classified by time scales and/or amplitudes that affect these laser operating parameters (e.g., 'Er bandwidth), as depicted in the graph of Figure 2, and if the serial number is 11 / 510 0 3 U.S. Patent Application No. 7 (ACTIVE SPECTRAL CONTROL OF DUV LIGHT 20 SOURCE,,, filed on August 25, 2006, published on August 23, 2007, 'publication number US-2007- This application is hereby incorporated by reference in its entirety in its entirety. As explained herein, in a fine actuation range 82 (eg, energy change or higher frequency duty cycle effect) or coarse actuation range 84 (eg, lower frequency duty cycle effects, gas aging unit 16 200908489: aging/mismatch Such interference 8Q within the quasi-) can be generated by a bandwidth controlled actuator (coarse actuation or fine actuation or both). Figure 3 shows a multi-stage gas discharge laser with a variable amplification line narrowing module and differential emission time (ship 0PA) bandwidth control. The first 5 stages can be: a primary oscillator M〇, and the lower _ stage can be a single channel power amplifier, a multi-channel power amplifier, a power oscillator or a row-wave amplifier (eg, a “power loop amplifier”). The oscillation occurs in the resonant cavity as an amplification stage. An example of such a ray may include some or all of the elements of the third item*, depending on the configuration. The component shown in FIG. 3 includes a variable amplification line narrowing module 502, a first stage chamber 5〇4, a first stage output coupler 506, steering optical elements 5〇8a, b, An input coupler 51, a second stage chamber 512, a beam splitter 514, a bandwidth measurement module 516, and a discharge timing control module 518. The source laser 5〇4 may be a gas discharge 15 excimer or a fluorine molecular laser such as an XC1, XF, KrF, ArF, F2 or similar laser. These types of lasers are known for lithographic processing of wafers to fabricate semiconductor circuits. The source laser 504 can define, for example, an optical resonant cavity between the line narrowing module 502 and the output coupler 506 and produce an output. The amplifier laser 512 receives the source laser output through the relay optics (reflector 20 mirrors 50 and b) and amplifies the source laser output to produce a laser system output. The bandwidth metric module 516 (known in the art) can measure the bandwidth of a laser output and can provide a bandwidth measurement that can be used by a bandwidth controller 518 (as discussed below). 518 can be an individual unit to produce a bandwidth error that can be compared to a target/setpoint 17 200908489. The differential timing can be adjusted based on the error signal to adjust the output bandwidth of the laser system. Figure 4 shows one possible embodiment of a bandwidth (and center wavelength) actuator mechanism (control center) having four prisms 520, 522, 524, 526 and a grating 528. The crucible 520 can be fixed to an actuator (not shown) that includes a rotationally movable fixation (e.g., a bend fixation (not shown), such that the crucible 520 can be transmitted through a rotary actuator (eg, A stepper motor (not shown) and/or PZT (not shown) rotates to increase/decrease the beam width, thereby changing the bandwidth. The crucible 522 can remain stationary or can have a rotational position actuator 10 (not shown). The crucible 524 is also fixed for rotational movement (as described for 稜鏡 52 )) (for example) to fine tune the center wavelength (e.g., in the order of femto (1 〇 -, 5 m)). The prism 524 can also be fixed such that the center wavelength is coarsely adjusted (e.g., on a scale of 10 x 1 〇 15 m). Figure 11 schematically depicts one possible embodiment of a bandwidth (and center wavelength) actuator (the center of the control 15), wherein the Rmax mirror 540 and its actuator 540a (for the laser system) As is well known in the art of center wavelength selection, it can be used to refract the extended beam from the beam spread 526 back to a grating 528. The grating 528 can be an elongated grating to use an extended beam, such as a beam that is extended 45X. By determining the angle of incidence of the beam on the optical 528 2 ,, the mirror 540 can be used in part for center wavelength control. The Rmax folding mirrors known in the art can have coarse and fine center wavelength control for a single optical component, ie, a stepper motor (not shown) for coarse control and a PZT stack (Fig. Not shown) for fine and fast center wavelength control' as noted above. When combined with a center wavelength 18 200908489 prism (e.g., 稜鏡 520), the Rmax mirror 54A can maintain its control relative to the angle of the grating 528 or use only fine control of the ρζτ stack without any stepping Motor control. The center wavelength control 稜鏡 (e.g., prism 520) can be used for coarse control, and then the Rmax folding mirror 54 can be used for fine center wavelength control, or vice versa. In the latter embodiment, the PZT stack can be deleted, and only one stepper motor is used to position the RMAX folding mirror for coarse center wavelength control, while the center wavelength control can be used for finer The center wavelength is chosen. Alternatively, the parent prisms in a series of rib 10 mirrors disposed within the beam expanding mechanism may have a coarse control and fine control similar to RMAX, wherein a stepper motor is used for coarse adjustment and a PZT stack is used for Fine adjustment, or upset adjustment, can be controlled using a stepper motor or similar mechanical adjustment, and § ( fine adjustment prism is controlled by a faster and thinner control actuator (eg one ΡΖΤ Stacking). The 15 signal can be received from the laser hardware to indicate the measured value of the Εν bandwidth from the most recent laser light. A controller (as shown in Figure 7) or a portion of components 5〇2 and/or 518 can then process the signals through various filtering, deadbands, hysteresis, and smoothing and generate one (plural) One (complex) of the form of the command is output to one (complex) actuator that can perform functions such as, for example, moving or distorting _ (complex) 20 mechanical and/or optical components. This (etc.) movement or distortion of the component can cause a change in the Εκ bandwidth to reduce bandwidth errors. There may be several control modes, such as the following but not limited to the following, in which no amplification control is implemented (i.e., the variable amplification LNM variation system is not used), so there is no effect on bandwidth control due to variable amplification. 19 200908489 In this mode ' can have two sub-modes, in one mode, dtMOPA laser timing is not used to directly control the bandwidth, and in one mode, dtMOPA is used to directly control the bandwidth.

In a second amplified drive mode, variable amplification is also unused, although the system drives the variable amplification to a selected value (e.g., to a maximum value, e.g., to 45X). In this second variable amplification mode, dtM〇pA is set for a first dtMOPA timing mode 'energy and timing control algorithm, and dtMOPA or variable amplification (except for being driven to a selected value, such as full 45χ amplification) ) have not been changed for bandwidth control. For a second dtMOPA 1〇 timing control mode, the bandwidth is set using dtMOPA while the amplification is maintained at, for example, 45X amplification. Another amplification control mode can be used, where amplification is based on some bandwidth feedback control bandwidth. The magnification can then be selected based on one of the bandwidth targets, as noted above. In this mode of amplification control of the first dtM〇pA control mode, the energy and timing control algorithm sets the dtMOPA timing for reasons other than bandwidth control, such as laser efficiency, dose stabilization or the like. . The magnification is selected to obtain a selected bandwidth independent of dtM〇pA. In the -second dtMOPA control mode, both the VMLNM's magnification and dtMOPA can be selected to achieve a target bandwidth, one of which is used as a coarse bandwidth selection mechanism and the other as a fine selection mechanism. The system can be set such that a deadband with a hysteresis configuration is used, such that, for example, control is initiated only when the error (absolute value) leaves a larger/outer sense band and returns to the error Closed when the smaller/inner is not sensed. Moreover, bandwidth motor jitter can be used, for example, using 20 200908489 to limit the value of the limit value in the - direction (four) microsteps before changing direction. In addition to utilizing the _bandwidth target change, the system can be configured to be paid for - given a guard cycle (eg, for example, 1 〇〇, ,, degrees, 5 就 1 )) The use of a new source within the time limit value of the same lithography source is disabled. This can limit jitter and/or customize f X control to specify customer requirements. 10 15 i 20 When the field filtered γ觅 is not sensed, the controller can command the step H in only one direction to prevent operation-related jitter near the band boundary. If the bandwidth (error signal) is greater than the high/outer sense band value, then the control enable bandwidth (4) actuation ϋ 触 / / / initial 彳 t command is issued, and the right bandwidth (error signal) is less than the low / inner non-sensitive band value, then The disable command is issued. Otherwise, the system does not change the current command-issuing state (enable or disable), while °H, wide (error signal) is between the high/outer sensed value and the low/inner sensed value. In other words, when the bandwidth (error) signal is in the middle of the non-inductive band limit value (has entered the region from a high value), the input command is issued, so that it remains enabled until the bandwidth (error) The signal passes through the low/inner sense and the command is disabled. Similarly, when a value from less than the low/inner sense band (where the command is issued is disabled), this function remains disabled until the bandwidth (error) signal passes the high/outer sense band value. The size of the insensitive band can be chosen to choose between several performance values, such as reduced jitter, controller response time versus total speed of interference, and the amount of bandwidth error allowed. The system can use a function generator (a rich feature set can be used) to (by way of example only) command a bandwidth controlled actuator (e.g., a stepper motor) to any function of the number of firings of 21 200908489. Individual hardware and software "gain, can be used for software (to promote hardware update capability). A controller delay (holdoff) can also be used, for example, at the beginning of 5 clusters, at No bandwidth stepping is allowed in some pulses, for example, within 3 bursts after the start of a burst. The three basic operations of the bandwidth control system may utilize a bandwidth actuator (eg, a variable amplification LNM). The firing process can occur on each firing (one shot is indicated by the LAM update). Bandwidth target change processing can occur when a bandwidth target change occurs 10. Whenever the line center (wavelength) analysis module ("LAM" ") When the wavelength data is sent back (for example, based on a firing-by-shot basis), the firing processing logic can be executed. With a firing data record, the input signal can be checked. The algorithm can execute it. The result is moved to the same firing data record. A Bandwidth Analysis Module ("BAM") status signal can be used to determine if new bandwidth data is available (eg E9 5 bandwidth data). The system can then taste Try to filter out bad or other invalid bandwidth data. 5H wide control system (for example, using a bandwidth control actuator (for example, - variable amplification line narrowing module ("VMLNM") bandwidth control system ) can be required to: (1) stabilize the bandwidth within a selected bandwidth, such as approximately 5 〇 m '(2) at a selected rate (eg, approximately 0.0003 fm/shot) from a selected target or setting Point correction bandwidth error; ensure that wavelength stability is maintained 'eg when using bandwidth control with bandwidth actuators allows for no more than a selected value (eg 'about 5 fm extra 55_fire moving average wavelength error 22 200908489 difference), and Not greater than - selected value (for example, an additional 55-to-spin movement standard deviation in wavelength error); (4) includes a magnetic (four) non-inductive band that can be used to change performance; (5) to prevent stepper motor jitter, Thus the stepper must be stepped at least in the - direction by a selected number (eg, approximately _ steps), before stepping in the other direction; and (6) provided for bandwidth target changes, which may be selected Time reached, example (For example, the training rate is 2 〇〇 pulse / sec. The minimum firing rate is about 10 seconds (for a 4 kHz pulse repetition rate laser system). Therefore, a filter can be used only when the bandwidth is updated. Between 1 new, other functions can occur (for example, step smoothing), but most of the other functions depend on the error being filtered. Therefore, if and if this does not change, the other control | § state is also constant The system can also use the bandwidth control algorithm determined by the 时序 timing mode and the BW stepper mode and can also use the BW stepper motor function generator/play and provide a “reset” of the bribe stepper to the baseline. Zoom in. - Mesh' can be requested to change for about 10 seconds in a selected time. Right mJ ^ See π change period, wavelength stability may not need to be in the second. Therefore, the money 11 may need to be at its fastest speed. The algorithm can command the stepper to move in the pj direction at the fastest possible rate and stop when the measured bandwidth approaches the target. The way to select 'T' is that the algorithm can use the position sensing of the bandwidth versus step curve and the absolute step to estimate the correct number of steps used to obtain the target bandwidth. If the number of firings in the current burst is less than or equal to a value stored 23 200908489 (representing the number of firings used to prevent bandwidth stepping at the beginning of a burst) and if the state of the target change mode is enabled ( "丨"), the system can set the number of steps used for this firing to =〇 based on feedback control. Based on the feedback control, the total number of bandwidth steps used for this firing can be calculated as the number of microsteps used to actuate the stepper (eg, a variable amplification prism rotary stepper) equal to a bandwidth control mechanism. The number of steps that are commanded. The algorithm output can be updated, for example, if the absolute value of the number of microsteps used to command the control actuator (eg, the variable amplification stepper) is greater than 〇 or if the current target change state is prior to the previous If the target change state is different, the output of the illusion algorithm can be set to 1, otherwise it is set to 〇. The algorithm rounding may be a signal indicating whether a new stepper command needs to be sent to the controller to actuate the bandwidth change to reduce the error signal (eg, whether a BWCM is enabled, as discussed below). A signal of the stepper is actuated by updating a bandwidth control mechanism. The stepper can be a variable-amplitude LNM rotary 稜鏡. When a target change is detected, the algorithm can be based on the currently filtered error, the previous bandwidth target, and the new bandwidth target—a new tracking error, ie, the filtered error plus the previous target minus the new one. Awkward goals. This provides the correct direction for the stepper to move. The algorithm can then reset (4) the waver to make the error of the chopping equal to the new tracking error. The system can command the stepper to move at the maximum rate in the desired direction (short for "slewing") until the filtered bandwidth error is in a selected one that is not overshooting in order to be able to stop the whirling Within the scope. The algorithm can also check if the filtered error changes the sign during the spin. If any of the conditions such as 24 200908489 are not met, the controller can return to normal control. The "spike" of the bandwidth may occur due to large wavelength changes. During a bandwidth change, the wavelength can also be affected by the coupling of the bandwidth step and the wavelength. Although the wavelength controller can compensate for this, the wavelength controller can compensate for this. Change, but its 5 cannot be done during the inter-band interval, so that the wavelength may change if the stepper continues to swirl. After the inter-band interval, the wavelength control may have to respond to a new and relatively large wavelength. Error. This can result in a fast and large change in wavelength, even with the ability to change substantially in 2 (four) - very fast (and fine) wavelength control mechanisms (eg based on a 10 RMAX PZT stack) or changing the grating The prismatic locating element of the beam of the person's angle of incidence (as a dominant wavelength control source). The change in wavelength during a BAM integration can be perceived by BAM as an increase. In general, the faster the wavelength changes, within the BAM measurement. The greater the positive deviation, the wavelength change is fast enough, in some cases, the peak of an abnormally large is reported by BAM. During a target change, these spikes It may be that the controller misinterprets (d) as indicating that the bandwidth swing has completed and returns to normal control very early before reaching the target. This may cause the target change to take much longer than the selected time, for example, greater than 10 seconds. The controller can implement several methods to filter out the bandwidth spikes. This tip 20 peak can be caused by a large wavelength change over a short period of time. When the wavelength changes more than a certain value during the BAM integration window - The bandwidth measurement is ignored when the quantity is: a chopper, the filter ignores the bandwidth measurement when the total range of the wavelength is included is greater than a predetermined value. The actual limit value of the actual bandwidth (adding noise) enables the it wave , thereby ignoring any bandwidth readings greater than a predetermined value (Example 25 200908489 eg, 2x maximum bandwidth). When a bandwidth reading is filtered/ignored, the last good (ie, 'not ignored') measurement can be The position is used. Typical values can be the maximum allowed wavelength TIR = 300 fm and the maximum allowed bandwidth = 1000 fm. 5 - The first few shots of the burst can generally be large and within the wavelength and energy Sometimes repeatable transients are characterized. The wavelength control algorithm can include logic that prevents transient overreaction of the bursts. However, the wavelength is more sensitive to interference during this initialization. Bandwidth stepping (this may Causing a wavelength change) can be prevented by a burst of the first selected number of firings, which in this application is referred to as a burst delay. The number of delayed firings is a controller operating parameter and can be approximately three According to another possible embodiment (as schematically depicted in Fig. 13), an LNM having four 稜鏡520, 522, 524 and 526 for controlling bandwidth and wavelength is displayed. Both of the 524 and 526 can be rotated by an actuator (not shown) similar to the actuators of the 稜鏡524, 526 shown in Figs. 4 and 5. A prism 526 can be rotated by a stepper motor actuator (not shown) and the other jaw 524 can be rotated by a PZT stack (not shown). The two turns 526 and 524 can be used for coarse and fine adjustment of the wavelength, respectively. They are positioned to respond to signals from a central wavelength controller system that respond to center wavelengths that are not on the target due to changes in the target or center wavelength. At least one of the other 稜鏡t can be rotated for bandwidth control, such as 稜鏡520. Rotation can be achieved with a stepper motor (not shown). Figure 5 is a block diagram depicting an overall architecture of a laser system controller 200 including bandwidth and wavelength control, generally discussed in U.S. Patent No. 6,690,704, issued to The controllers are identical, with a bandwidth control module ("BWCM", 220 and a variable amplification line narrowing module ("VMLNM") 222. A launch control platform ("FCP") processor 202 can control (for example) a discharge of discharge between electrodes in a single chamber laser system (eg, Cymer's 5 7000 series laser system) or a source laser amplifier configuration (eg Cymer's XLA series of ΜΟΡΑ laser systems) Or the emission of discharge between the electrodes in each of the plurality of laser chambers in the XLR series of ring power amplifiers ΜΟΡΟ laser systems. The 202 can use control algorithm software and provide control signals to a launch control 1〇 communicator ("FCC") 204. The FCP 202 can respond to and communicate with a command signal from a laser control processor ("Lcp") 2〇6. The FCC 204 can be self-lighted Beam Analysis Module ("BAM") 210 (some similar to the Spectrum Analysis Module ("SAM") (for bandwidth) and the Line Center Analysis Module 15 ("LAM") 212 discussed in the '704 patent (using The wavelength and bandwidth information is received at a central wavelength and the FCP 202 can be interrupted to perform a wavelength or bandwidth control algorithm or both. The FCC 204 can also pass the FCP 202 command to a bandwidth control module ("BWCM"). 220' The BWCM 220 can be used to command all actuators used to control bandwidth or wavelength, for example, there can be a variable amplification line narrowing 20 module ("VMLNM") 222. VMLNM 222 and its The state of the actuator can be communicated back to the FCP 202 through the FCC 204. Figure 6 depicts a representative laser system "implantation model" in block diagram form with a bandwidth (or possibly wavelength) stepping The motor motor step command 232 can be input to an adder 234 and summed with one of the same delays 236, 27 200908489, to provide an input to a step-by-step BW lookup that produces a desired bandwidth value for the BW lookup. , the expected bandwidth value is input to an addition 242 and summing with a representative interference from interference block 240. After a sample delay block 244, the output of adder 242 is summed within adder 246 by a constant from constant block 248 and from noise block 247. The noise sums up to produce a representation of the measured bandwidth on output 249. Figure 7 shows an illustrative example of a bandwidth controller 250. The controller 250 may have a bandwidth (or possibly wavelength) target 252, the measured bandwidth (wavelength) 254 and the input of the wavelength TIR 256, the latter two of which are input to a 10 "bad" bandwidth measurement processor 257, one of the "good" bandwidth outputs in an addition The target 258 is summed with the target bandwidth input 252 to provide an input to a noise filter 260. If the bandwidth measurement needs to be filtered/ignored (eg, because the measurement or TIR is too large), then the output of block 257 will be a previously measured "good" bandwidth, otherwise the measured bandwidth may be Pass block 257. 15 § Xuanzi said that the output of the filter and Boyi 260 provides an input to the step-by-step command path, a mode selection path, and a whirling step path. The step command path may include a non-inductive strip having a hysteresis "on/off" block 262, an example of which is described in more detail in FIG. If the non-inductive output with hysteresis is fed back to the enable enable/start mode (eg, ' a 1), then the output 20 of the multiplier 270 is the output of the noise filter 260 and if it is fed back With the disable/off mode 0, the output of the multiplier 270 is 〇. The output of the multiplier 270 is amplified by a gain factor κ in the control gain amplifier 272 and passed through a command saturation block 274 to a step-by-step smoother 276, an example of which is shown in detail in FIG. . This command saturation block can be used to limit the effect of the 200908489 bandwidth step rate on the center wavelength control. A limit value can be established equal to the maximum step per picture (e.g., each time the bam/bandwidth measurement updates 0.1 times (nominally 3 〇), in this case it will be 3 steps). The mode selection path may include a control mode selector 264, an example of which is shown in detail in Fig. 10. The mode selector (10) receives the output of the noise chopper 260 (on a Bw error input) and - the output of the target change detector 268 is an input, the target change detector 268 having a bandwidth from the input 252 The goal - the input side. The output of the target change detector 268 forms an input of the target change input of the mode selector 264. The whirling step path can include a plus sign block 266 that receives the output of the noise waver (10), the output of the sign block 266 being amplified by a factor N in a target change whirling stepper amplifier 278. The output of each of the paths such as shai provides input to an individual terminal of a three-pole switch 280, the output of which is a one-step command 284. Figure 9 is a block diagram depicting a non-inductive hysteresis control block 262' which can have the output of the noise filter 260 as an input 29〇, as depicted in Figure 7. The input 290 can be provided to an absolute value function block 292 'The output of the absolute value function block 292 can be provided to a relay block 294'. The relay block 294 can include (as an example) a symmetry with hysteresis 20 switches to provide an "on/off", output 296. This symmetry is greater when the bandwidth error (or possibly the bandwidth measured by the non-inductance within the bandwidth itself, as opposed to the bandwidth error) is greater than the outer/high non-inductive value Switch 294 can act to generate a 'on" output ("1") and, when it is less than the inner/low bandwidth value, produces an "off" ("0"). When using the absolute value of the error signal compared to a high or low non-inductive value 29 200908489 value, the use of bandwidth error is only logically easy to implement. If the previous output is a 'Ί''/"ON", the switch 294 can generate an "on," output when the bandwidth error is between the high/outer sensed value and the low/inner sensed value. And vice versa when the previous output is "〇'V". This is the meaning of the hysteresis in this article. As described in Figure 8, the step-by-step smoother 276 can take the one-step command as an input 'e.g., from the step command 274 of the command saturation block 274 illustrated in Figure 7. The step smoother 276 can include a divider that divides the input step command c of the advanced step by the number (or time) T of 10 shots used to advance the c number of steps. The output of the divider 340 provides an input to an adder 342 and a block 360. The output of the adder 342 is provided to a multiplier block 346 whose output X step is rounded to the nearest integer within the rounding block 35A. The output of block 350 forms an output command of one of the steps of s, which is provided to switch 280 as described in FIG. The output of the multiplier block 346 is also subtracted from the output of the rounding block 35 within an adder 348 to provide an input to the same local delay 344, the output of which provides an input to the adder 342. . There is a need to ensure that there is a limit on the bandwidth control actuator step to limit the effects of wavelength control (eg, wavelength lock), which may be every 10 firing S! BW steps to maintain machine lock (which should not Is an average) 〇 BW control loop every 30 firings (corresponding to bam update rate) is ordered 'when the control loop is expected to have a maximum of 3 steps P white during the 3 firings) This will average to only! Step / 1 〇 firing. However, if the BWCM - all three orders are ordered, then the (4) system requirements may be disturbed. There is a need to evenly distribute the steps during 30 200908489 30 firings, which is performed by the step slider 276. The input (command c step) is also provided to an adder 3 64, which is output within the adder 364 and the output 5 of the rounding block 350 in the adder 370 and the output delayed in block 368. The result of a single sample delay sum is summed 'where the output of the adder 364 provides an input to a single sample delay block 366. After the same delay in block 366, the output of block 364 provides an input to an absolute block 354. The output of block 354 is compared in block 352 to check if it is greater than a value "r", the value "r" source 10 is at the intercept block 360, wherein the result of the division in block 340 is removed by removing any of the results. The decimal portion is truncated and summed with a constant (e.g., 1.0) in adder 358, and multiplied by a value (e.g., 0.5) within multiplier block 356 to provide an input r to comparator block 352. The elements of the step smoother 256 outside the dashed line ensure that the step stops after the number of steps 15 (i.e., c) required to be commanded. Otherwise, if there is no BAM update for a BAM update next time, the stepper may only keep stepping the bandwidth control mechanism even if a no-in/down limit value is passed. The controller 250 can have several parameters, the values of which can be selected and the representative values are noted in parentheses, for example, the noise filter coefficient c (〇9735), the controller gain κ(1), Does not sense the inner and outer limit values ((1.0 fm) and d〇 (9.5 fm) respectively), the command saturation limit value L (2 steps per BAM update period), the target-change-complete error limit value m ( 15 fm), the maximum allowed wavelength TIR (3GG··fm) and the maximum allowed bandwidth (__1〇〇〇fm) 〇31 200908489 Given these factors (eg sensor noise, performance requirements and Robustness), when determining the overall performance within a closed loop, the parameters can be combined in a highly nonlinear manner. Therefore, the applicant has decided to choose a parameter that starts to be loosely coupled. The maximum allowed TIR is selected based on 5 experiments during a target change maneuver, which is considered to be a worst case continuous operation. For an exemplary ArF laser system, in normal operating conditions, the maximum possible bandwidth is approximately 300-500 fm, so the number 2 gives the selected limit value. In the case of an ArF laser system, Μ is selected because a single filtered test signal may have a large delay between the actual signal and the test signal, 10 resulting in early stopping of a target change cyclotron to prevent excessive overshoot. For L, because the bandwidth and wavelength stepper may affect the bandwidth, the wavelength stepper can be moved to compensate for a bandwidth stepper movement (a control center bandwidth control actuation), such as through the wavelength controller saturation. The change in wavelength due to the bandwidth step can be offset by the wavelength step. For Κ (with wave 15 long stepper rate limit), the controller has a virtually unlimited gain margin. The control gain is selected so the command is always always saturated, providing the fastest response time. When the bandwidth stepper provides ~0.005 fm per step (2 steps per 30 shots), each shot 0.00033 fm meets other system requirements. For dQ = 9.5, the tuning does not sense the value of the mountain, (for example, 20 for customer bandwidth control requirements) and the use of re-filtering to indicate that the filtered value is the actual instantaneous bandwidth (except in the bandwidth (eg, step) fast Change), d. Can be provided in the actual bandwidth of the nominal no sense. Bandwidth measurement noise is similar to white Gaussian (standard deviation ~20 fm, one of the total bandwidth is less than (2*9.5 = 19 fm)) is reasonable to limit the actuation of the stepper. The inner sense is not limited to the value of the mountain = 32 200908489 1.0 can maximize the non-inductive hysteresis, minimizing the jitter of a control center within a bandwidth control command to actuate the stepper or other actuator. Moreover, when the bandwidth is measured at a resolution of about 1 fm, it is ineffective if the inner non-inductive band is set less than 1 fm. For C, increased stability and blocking of noise filtering can also increase latency, an excessive amount of which is undesirable. Command saturation can be selected from the ratio of wavelength variation to wavelength and bandwidth controller actuation steps, and it is desirable to compensate a bandwidth actuation step with a single wavelength step and round to integer steps because if rounded, then The wavelength stepper may make the bandwidth step backwards. For a 30-shot BAM integration period, the wavelength control allows one wavelength step to be fired every 30. Therefore L = 2 (which is approximately 0.00033 per shot) meets the system requirements. If the size of the steps needs to be increased (or their effect on bandwidth), this may reduce the gain margin. The step response of the noise filter can be: yk = u(l-ck)+y0 +vk 15 where U is the size of the step input, y〇 is the initial output, C is the coefficient, and v is the filtered impurity. And k = 30* (number of shots). When a stepping disturbance occurs, the controller 250 does not sense the band, and the control action may not start until the filtered error increases to d. Above, the time required is an initial delay produced by the filter. When y crosses the non-inductive band, the solution k: u(l-ck)+y0 +vk >d0 ck<u + y〇-d0+vk=> u ln(u + y0-do+vk)-ln( u) ιφ) where C<1 is known. Suppose that before the actual filtered bandwidth reaches the insensitive band (due to noise and ignores the "spike" of the noise), the band is not (average) 1 sigma 33 20 200908489 horse 'where d'. > y〇 and avoid U + y〇 < d. (indicating U + y〇 - d. > ο), when 11 is large and U + y〇 - d. In hours, k can be maximized. Even so, there may be a combination of interference and one of the initial conditions such that the filtered error passes through d for almost infinite time. , has nothing to do with c. When using the bandwidth measured by 1 fm resolution (u + 5 y 〇 - d. The minimum value = 1 is reasonable) and use d. = 9.5 (minimum u + 丫〇 - (1. = 1 u is the maximum value is u = 2 * ci0 + 1 = 20), an initial condition can be set at the "bottom" of the inductive band, and a stepping interference is sufficient Leave the "top" without feeling. The first-order filter response (no overshoot) may take the longest time to exit the non-inductive band. When with 30 shots per sample and a maximum of 10 hits per second of 200 shots/sec, leave The maximum time that you do not feel the tape can be determined as follows:

Where is the sensor noise standard deviation ' (for example) equal to 2 〇 fm. This defines an absolute worst case, and a Monte Carlo study shows that the typical delay is less than 0.5 seconds, resulting in a delay of 1 〇 (a reasonable choice) so that a filter coefficient of 15 = C = 0.9735 is reasonable. . A stepper motor in combination with one of the BWCMs can be used as an accumulator (integrator) with a rate limit (4000 microsteps per second) which can also be completely noise free. BW is a non-linear function of the absolute stepper position and can also have a negligible coupling from WL to BW' which allows for individually closing the 0" control loop and is independent of the other loops. However, 'from BW粞The combination of ~[and the derived WL error S 5 fm may require special considerations. Although the controlled implant can be used as a natural integrator (with good noise rejection characteristics), 34 200908489 may also require additional Filtering to help prevent jitter within the stepper command. The system may seek to move the bandwidth control mechanism stepper to a baseline position, such as a baseline amplification or a baseline aperture or the like. Using a limit switch (eg, within the LNM) is performed, issuing a large number of steps (for example) to maximize amplification and waiting for an interrupt signal from a different limit switch, which causes the BWCM to be due to a signal from the limit switch Stop command stepper actuation. It can also be applied to other bandwidth control actuators, such as an adjustable aperture. The limit switch position should be set to 10 bandwidth settings. For example, a known amplification or a known aperture size and position. When this function is implemented, a BW versus step curve can also be measured and updated. Applicants have simulated this bandwidth control system and decided from this simulation system The response can be dominated by the algorithm BW stepper rate limit value (eg, ~0.0005 fm/shot). Filtering, waves can effectively improve the noise response to reduce the insensitive band 15. The controller gain can be set high enough so that The stepper command is always saturated or “off.” The system can achieve error = (without sensing) + (~3σ filtered noise), the error is "sneak" when the noise spike triggers the accidental stepping Lower (assuming no interference). This dive can be minimized by increasing the hysteresis. The non-inductive noise filter can effectively eliminate jitter. The system can be highly robust, with one virtually no Limited gain margin. The BW stepper rate limit and no sense band prevent noise from injecting the system into the system. A center wavelength selection mechanism can include a dispersive optical component and the center wavelength is selected. And/or other central wavelength selective optics controllable 35 200908489 Adjusting the angle of incidence of the beam on the dispersive optical element. The differential timing system can include a coarse bandwidth control adjustment, or vice versa. Thick and thin bandwidth and / Or various combinations of central wavelength control actuations may be used. According to another possible embodiment (illustrated schematically in Figure 13) 'a has four 稜鏡520 for controlling bandwidth and wavelength, The LNM of 522, 524, 10 15 20 526 is displayed, wherein the two turns 524 and 526 can be rotated by an actuator (not shown) similar to the actuators of the ports 524, 526 of Figures 4 and 11. A prism 526 can be rotated by a stepper motor actuator (not shown) and the other jaw 524 can be rotated by a -PZT stack (not shown). The two 526 and - can be used for coarse adjustment and fine adjustment of the wavelength. They are positioned according to the signal from the medium-wavelength controller system, responding to the central wavelength due to target changes or center wavelength drift without being on the target. At least one of the other ports can be rotated for bandwidth control, such as & J, for example 520. Rotation can be achieved with a stepper motor (not shown). A 禋 凌 3 3 is used to control ~ (for example, - ΜΟΡΑ or M0P0 雷 ^ (4) amps lasers may be more suitable for -MOPQ laser, 糸 system) frequency profile (bandwidth), level) 512 energy. This side has a reduced input to the second system, which may be used for - or & may not rely on dtM 〇 PA timing, such as energy stability, has an undesired = his laser system operating parameters (timing control can be It is used to augment the negative politicians here, although the dtM0] method can be used to provide - the device and method of the laser control #. The device system. ^ 1 The symmetry and asymmetry of the cheek spectrum use one稜鏡 and / or folding goggles and based on the grating spectrum narrow 36 200908489

The output spectrum of the laser of the method may have a spatial non-uniformity of wavelengths, for example, in a direction perpendicular to the sawtooth structure of the grating. Figure 16 depicts an example of a change in bandwidth that depends on the size of the aperture through which the beam passes. By way of example, an adjustable aperture (e.g., 158 in Figure 14 or 610 in Figure 15 or as shown in the co-pending patent application Serial No. 11/173,988 The patent name is "ACTIVE BANDWIDTH CONTROL FOR A TUNED LASER", filed on June 10, 2005, the entire disclosure of which is hereby incorporated by reference herein in The system output spectral bandwidth can be controlled by selecting a portion of the laser beam and injecting a portion of the beam into the power amplifier or power oscillator (e.g., amplifier 512, which is schematically depicted in FIG. 3). A power amplifier or power oscillator (eg, 512 in Figure 3) that is used as the second stage (amplifier) may require some-input beam size, which may be by two lenses or similar devices (eg, a beam expander (eg, a beam expander ( As an example) a combination or another adjustable aperture is provided to adjust the beam size and shape it after it passes through the aperture 'eg, expand the beam and make it parallel to select - the desired portion for adjustment Or choose the purpose of bandwidth. By way of example, an adjustable beam spread collimator, as schematically depicted in Fig. 15, can be used. A bandwidth monitor (e.g., within a Band Analysis Module ("BAM") 516 in Figure 3) can provide a feed signal to the bandwidth controller (e.g., 62 in Figure 15). The bandwidth controller can adjust the portion of the beam passing through the adjustable 610 using the bandwidth signal. For example, in the case of the selection, the aperture size and beam shaping are controlled to select the bandwidth and the beam to the amplification stage of the laser system to provide the spectrum. Symmetry of shape (bandwidth) and non-comprising 37 200908489 Sense control 'This can be performed, for example, within the adjustable beam expander/collimator 600. It will be appreciated that the bandwidth of the source laser beam (e.g., the MO beam) prior to the adjustable aperture should be large enough to provide a desired range of spectral bandwidth after the adjustable aperture. 5 Right expectation, in accordance with the subject matter of this disclosure, for the benefit of laser operating parameters other than bandwidth (eg, _energy, dose regimen, and the like) 'dtMOPA timing can be used independently to allow for centist 1> The laser operates at its optimal dtMOPA timing while the adjustable aperture 61〇 or other form of active bandwidth control can be combined with one or more other bandwidth controlled actuators (as a coarse 10 or fine adjuster or with relatively equal adjustments) Speed) is used as a bandwidth selection actuator (control center) to select the bandwidth. Alternatively, the dtMOPA bandwidth selection actuator can only be used for fine adjustments, so that from other operational perspectives (eg, pulse energy stability, dose stability, or the like), there is no need to deviate significantly from the most Good dtMOPA. 15 Because the energy stability of a source laser amplifier laser (such as helium or neon) may be strongly affected by the energy input to ΡΑ/ΡΟ, it may be desirable to have individual voltage controls for ΜΟ and ΡΑ/ΡΟ to adjust and Controls the chirp energy output independent of the amplifier section, such as ΡΑ/ΡΟ. An adjustable aperture may be rectangular to adjust within the short axis of the beam, 20 which is typically within the applicant's transferee's laser system (eg, Cymer's 7-inch series or XLA or LXLR series laser systems) The adjustment of the size in the horizontal direction is as shown in the example in Fig. 4 in the case of narrowing the laser in a line. As described in Fig. 15, the beam can be expanded to improve controllability prior to the adjustable aperture', e.g., using a beam expander 612, a chirp or a majority 38 200908489 f

One lens or a lens combination and the like. After the beam is partially selected by the adjustable aperture, it (as noted above) can be expanded/compressed and collimated to meet the beam size requirements of the PA or ( (eg, in the adjustable beam spread collimator) Inside), this can, for example, be a telescope or an adjustable telescope with 5 independent collimating lenses. Beam spreading may not be required for a -ΜΟΡΟ configuration where the beam size in the region of the amplifier electrodes during discharge between the electrodes may not be as large as a (multiple) fixed channel amplification. The scalloped optical element may also, by way of example, be a combination of a cylindrical translucent having a distance between two tuned lenses. For symmetric spectrum control, the center of the adjustable aperture can be adjusted to the center of the beam. For asymmetric spectrum control, the aperture can be adjusted to move within the -axis (e.g., in the horizontal direction toward one edge of the beam or another: the edge) to, for example, increase or decrease the wavelength. For some disturbances of the laser operating parameters (e.g., with respect to beam quality, such as bandwidth), the variation is more likely to occur in the vertical direction of the beam. As an example of repetition rate dependent interference, this is true. Thus, the variable aperture described in _ can be rotated within the plane of the page being described. And select the - vertical portion of the beam for beam quality parameter selection (e.g., 'bandwidth selection'). This can also be performed using another aperture described in Figure 14 - Selecting the aperture series just 20 . For some applications, the variable amplification line narrowing module 502 can respond to the money generated by the bandwidth measurement module 516. The variable amplification line narrowing module 502 can be used for coarse bandwidth control, utilizing bandwidth control rotatable 〇52〇, and one or both of another bandwidth control actuation 522, 524, and/or 526 39 200908489 (eg differential emission time (dtM0PA) or grating bending, for example using the bandwidth control device ("bcd") varnish deformer shown schematically in 630 in Figure 7, or in the cavity or External - variable aperture can be used for fine bandwidth control. Each of the bandwidth selective actuators can be used in conjunction with any one or more of the other actuators 5 as one or the other of a coarse control actuator and a fine control actuator By. It will be apparent to those skilled in the art that the above-described embodiments of the present invention are intended to satisfy the requirements of at least the consistent embodiments of the subject matter of the disclosure The exemplary embodiments are not intended to limit the scope of any claims and are not intended to be limited to a particular disclosed embodiment. It will be apparent to those skilled in the art that many variations and modifications can be made in the disclosed aspects of the disclosed embodiments of the subject invention. Description. The scope of the appended claims 15 is intended to cover the scope of the disclosed subject matter, and such equivalents and other modifications and variations are obvious to those of ordinary skill in the field. . In addition to the above-described changes and modifications of the disclosed subject matter of the present invention, other variations and modifications can be implemented. 20 [Simple diagram of the diagram] Figure 1 shows the sensitivity curve of a bandwidth control device E95; Figure 2 depicts the interference type and time scale and amplitude of the layer according to one of the disclosed targets; Figure 3 Illustratively and in block diagram form a multi-level with a variable amplification line narrowing module and differential transmission time (dtMOPA) bandwidth control in accordance with one aspect of the disclosed embodiment #200908489 Gas discharge laser system; Figure 4 is a schematic and block diagram showing an embodiment having four prisms and a grating in accordance with the disclosed embodiment, wherein at least one prism Can be rotated to increase/decrease the beam width to change the bandwidth; Figure 5 depicts the overall architecture of a laser control system that can be used for level c of one of the disclosed embodiments; 10 Figure 6 is schematic and The block diagram depicts a representative laser system "implantation" in accordance with the level of control of one of the disclosed embodiments; Figure 7 is schematically and in block diagram depicting implementation in accordance with one of the disclosed targets A bandwidth controller of the level of the example; FIG. 8 schematically and in block diagram form a firing smoother according to the level of one embodiment of the disclosed target 15; FIG. 9 is schematic and is a block The diagram depicts a non-inductive hysteresis block in accordance with the level of one embodiment of the disclosed subject matter; FIG. 10 is a schematic and block diagram depicting aspects of an embodiment in accordance with the disclosed subject matter. A control mode selector; 20 Figure 11 is a schematic and block diagram depicting an embodiment having a plurality of chirps and a center wavelength selective mirror in accordance with a level of an embodiment of the disclosed subject matter; The figure depicts an E95 bandwidth control center using AtMOPA; Figure 13 schematically depicts a variable amplification LNM of the layer of embodiment 25 in accordance with the disclosed subject matter; 41 200908489 Figure 14 is schematically and The block diagram depicts an adjustable aperture bandwidth control actuator centering in accordance with one level of an embodiment of the disclosed pole; FIG. 15 is schematically and in block diagram representation in accordance with the disclosed Subject According to a level of a bandwidth control system embodiment; and examples of the variations and Figure 16 a schematic of the beam passes through the aperture size dependent bandwidth. [Main component symbol description] 80... Interference 82.. . Fine actuation range 84.. . Rough actuation range 158.. Adjustable aperture 200.. . Laser system controller

202.. .FCP

204.. .FCC

206.. .LCP

210.. .BAM

212.. .LAM 220.. . Bandwidth Control Module 222··· Variable Magnification Line Narrowing Module 232.. Step Command 234.. Adder 236.. . Sample Delay 240.. . Block 242.. Adder 244. Sample Delay Block 246... Adder 247... Noise Block 248.. Constant Block 249... Output 250... Bandwidth Controller 252···Bandwidth Target 254...Measured Bandwidth

256...wavelength TIR 257...processor 258...adder 260...noise filter 262··.without hysteresis control block 264...control mode selector 266...symbol block 268.·target change detector 270...multiplication 42 200908489 272.. Control Gain Amplifier 274.. Command Saturation Block 276.. Step Smoother 278.. Target Change Swirling Stepper Amplifier 280.. Three-Phase Switch 284.. Step Command 290 .. Enter 292.. Absolute value function block 294.. . Forwarding block 296.. Output 340.. Divider 342.. Adder 344.. Sample delay 346.. . Multiplier block 348. Adder 350.. . Rounding block 352.. . Block 354.. Absolute value block 356.. Multiplier block 358.. Adder 360.. . Intercept block 364.. Adder 366. Sample Delay Block 368.. Delay Block 370.. Adder 500.. Multi-Level Gas Discharge Laser 502.. Variable Magnification Line Narrowing Module 504.. First Stage Chamber 506 The first stage output coupler 508a...turns to the optical element 508b...the steering optical element 510..the input coupler 512..the second stage chamber 514..the beam splitter 516. . Bandwidth measurement Module 518.. discharge timing control module 520.. prism 522.. .稜鏡524.. .稜鏡526.. .稜鏡528.. grating 540.. .Rmax mirror 600.. . Adjustable beam spread collimator 610'... adjustable aperture 612.. beam expander 620.. bandwidth controller 630.. bandwidth control device 43

Claims (1)

200908489 X. Patent application scope: 1. A method for controlling bandwidth in a laser system, the laser system comprising: a gas discharge source laser having a resonant cavity and generating a source 5 laser output; a gas discharge amplifier laser that amplifies the source laser output and produces a laser system output; a bandwidth metric unit that measures the bandwidth of the laser system output and provides a bandwidth measurement; and a bandwidth error signal generator Receiving the bandwidth measurement value and a bandwidth set point and providing a bandwidth error signal; a variable amplification line narrowing unit located in the resonant cavity of the source laser, comprising a grating and a variable beam amplifying optical system a differential timing controller that selects a timing of an electrical discharge between a pair of 15 poles of the source laser and a pair of electrodes within the laser of the amplifier; the method comprising the steps of: utilizing A bandwidth controller controls the bandwidth, and the bandwidth controller has three modes of amplification control, wherein a first mode does not control the line narrowing 20 Amplification of the beam within the element, a second mode driving the amplification of the beam within the line narrowing unit to a selected value independent of the bandwidth error signal, and a third mode driving the band based on the bandwidth error signal The amplification of the beam within the line narrowing unit; and wherein in each mode, the differential timing controller selects the timing based on the bandwidth 44 200908489 error signal or does not consider the bandwidth error signal. 2. The method of claim 1, further comprising the steps of: controlling the line in the narrowing unit according to the bandwidth error signal by using an inner bandwidth non-inductive band value and an outer bandwidth non-inductive band value; The amplification of the beam, wherein the bandwidth controller is driven according to a bandwidth between the non-inductance value and the external non-inductance band value only if the controller affects a bandwidth change such that the bandwidth is close to the inner bandwidth non-inductance value. The line narrows the amplification of the beam within the cell. 10. The method of claim 1, further comprising the steps of: using two modes of bandwidth error reduction; a first normal bandwidth error reduction mode, wherein the bandwidth controller performs a bandwidth error reduction command to Will greatly affect another laser system operating parameter in addition to bandwidth 15; and a second bandwidth target variation error reduction mode in which the bandwidth controller performs a bandwidth error reduction command to change to a new bandwidth target, regardless of The effect of the operating parameter of the other laser system; and when the bandwidth target produces a change, the controller switches to the second 20 error reduction mode, and when the new bandwidth target is reached, switches to the first error Reduce the mode. 4. The method of claim 2, further comprising the steps of: using two modes of bandwidth error reduction; 45 200908489 帛iL hoist bandwidth error reduction mode, wherein the bandwidth controller performs a bandwidth error reduction command to Will greatly affect the operating parameters of another laser system in addition to the bandwidth; a second bandwidth target change mis-line mode, wherein the bandwidth controller performs a bandwidth error reduction command to change to a new bandwidth target, regardless of the impact on the operational parameters of the other laser system; and... when the bandwidth target is generated - When changing, the control is difficult to switch to the second °, salt / mode 'h to switch to the first error reduction mode when the new bandwidth target is reached. 5. The method of claim 2, the method comprising the steps of: limiting bandwidth actuator jitter to a minimum number of steps in a first direction, and dithering in a second opposite direction prior to. "Please refer to the method of the fourth rhyme in full-time, enter - and * * 20 limits the bandwidth actuator jitter to a minimum number of steps in a first direction - before the jitter in the second opposite direction. As described in claim i, the method further comprises the steps of: - when the bandwidth target is changed, based on the measured bandwidth between the measured amount of time and the new target bandwidth - The bandwidth controller _ to the bandwidth target of the cartridge, and the ray (four) system is considered to be within the specification at the selected time. The method of claim 4, further comprising the following step 46: 200908489: when the bandwidth target is changed, based on the measured bandwidth between the measured bandwidth and the new target bandwidth An error drives the bandwidth controller to the new bandwidth target and the laser system is not considered to be within the specification for the selected amount of time. 9. The method of claim 1, further comprising: using a function generator to command a bandwidth selection to actuate the stepper. 10. The method of claim 4, further comprising: using a function generator to command a bandwidth selection to actuate the stepper. 10. The method of claim 9, wherein: the function generator commands the bandwidth selection actuator based on an arbitrary function of the number of shots. 12. The method of claim 10, wherein: the function generator commands the bandwidth 15 to select an actuator based on an arbitrary function of the number of shots. 13. The method of claim 1, wherein: the bandwidth controller comprises a bandwidth selection actuator step command smoother. 14. The method of claim 12, wherein: the bandwidth controller comprises a bandwidth selection actuator step command smoother. 15. A laser system comprising: a gas discharge source laser having a resonant cavity and producing a source laser output; 47 200908489 A gas discharge amplifier laser amplifying the source laser output and generating a thunder a system of measuring a bandwidth, measuring a bandwidth of the output of the laser system and providing a bandwidth measurement; and a bandwidth error signal generator for receiving the bandwidth measurement and a bandwidth set point and providing a bandwidth error signal; a variable amplification line narrowing unit, located in the resonant cavity of the source laser, comprising a grating and a variable beam amplifying optical system; a differential timing controller selecting one of the source lasers a timing of a discharge of a discharge between a pair of electrodes and a pair of electrodes within the laser of the amplifier; a bandwidth controller having three modes of amplification control, the bandwidth controller not controlling the variable amplification line a first mode of the narrowing unit, the bandwidth controller controls the variable amplification line narrowing unit to drive the 15 amplification to a bandwidth error signal a second mode of the selected value, and the bandwidth controller controlling the variable amplification line narrowing unit to select a third mode of the bandwidth of the laser system output according to the bandwidth error signal; and wherein the differential timing The controller selects the timing according to the bandwidth error signal or does not consider the bandwidth error signal. 16. A laser system comprising: a laser source comprising: a source laser defining an optical resonant cavity that produces an output; an amplifier laser that receives the source laser output and amplifies the source 48 200908489 Laser output; a bandwidth measurement module, measuring a bandwidth of a laser output light pulse pulse generated by the light source and generating a bandwidth measurement value; a bandwidth error signal generator receiving the bandwidth measurement value and a band width of 5 The set point is provided and a bandwidth error signal is provided; a bandwidth selecting component located outside the resonant cavity of the source laser, and a spatial portion of the beam is selected to selectively vary the bandwidth of the source laser output. 17. The laser system of claim 16, wherein: the bandwidth selection component comprises an adjustable aperture. 18. The laser system of claim 16, further comprising: a second bandwidth selection actuator cooperating with the bandwidth selection element to select a bandwidth of the laser system. 19. The laser system of claim 18, wherein: the second bandwidth selection system comprises a differential emission timing system that adjusts a differential between the source laser and the amplifier laser Launch time. 20. The laser system of claim 19, wherein: the adjustable aperture comprises a coarse bandwidth control actuator and the differential emission timing system comprises a fine bandwidth control actuator. The laser system of claim 16, further comprising: a beam expanding system that extends the size of the beam incident on a bandwidth selective optical element. 22. The laser system of claim 20, further comprising: a beam expanding system that extends the size of the beam incident on a bandwidth selective optic element 49 200908489. 23. The laser system of claim 19, wherein: the adjustable aperture comprises a coarse bandwidth control actuator and the beam expansion system comprises a thin bandwidth control actuator. 5. The laser system of claim 19, wherein: the adjustable aperture comprises a thin bandwidth control actuator and the beam expansion system comprises a coarse bandwidth control actuator. 25. The laser system of claim 16, further comprising: a bandwidth control device that modifies the shape of the incident portion of the light beam of one of the bandwidth selective optical elements. 26. The laser system of claim 24, further comprising: a bandwidth control device that modifies the shape of the beam incident portion of one of the bandwidth selective optical elements. 27. The laser system of claim 19, wherein: 15 the adjustable aperture comprises a coarse bandwidth control actuator and the bandwidth control device comprises a thin bandwidth control actuator. 28. The laser system of claim 20, wherein: the adjustable aperture comprises a thin bandwidth control actuator and the bandwidth control device comprises a coarse bandwidth control actuator. The laser system of claim 16, further comprising: a beam expander positioned between the bandwidth control element and the amplifier to adjust a beam size entering the amplifier. 30. The laser system of claim 17, further comprising: a beam expander positioned between the bandwidth control element and the amplifier, 50 200908489 adjusting the beam size entering the amplifier. 31. The laser system of claim 29, further comprising: a beam collimator positioned between the bandwidth control element and the amplifier to collimate the beam entering the amplifier. The laser system of claim 30, further comprising: a beam collimator positioned between the bandwidth control element and the amplifier to collimate the beam entering the amplifier. 33. The laser system of claim 31, further comprising: a beam expander located between the source laser and the bandwidth control element. 34. The laser system of claim 32, further comprising: a beam expander positioned between the source laser and the bandwidth control element. 35. The laser system of claim 33, wherein: 15 the beam expander and the beam collimator comprise a beam size adjustment collimator. 36. The laser system of claim 34, wherein: the beam expander and the beam collimator comprise a beam size adjustment collimator. 20 37. A laser system comprising: a source laser defining an optical resonant cavity that produces an output; an amplifier laser that receives and amplifies the output of the source laser and provides a laser system output; a bandwidth metric module for measuring a laser output generated by the light source 51 200908489 optical pulse beam pulse bandwidth and generating a bandwidth measurement value; a bandwidth error signal generator receiving the bandwidth measurement value and a bandwidth set point and providing a bandwidth error signal; a differential timing system that echoes the bandwidth error signal to selectively adjust a differential emission time between the source laser and the amplifier; and a beam size adjustment system that adjustably adjusts the a beam size of a beam within the resonant cavity of the source laser to selectively vary the bandwidth of the source laser output and controllably adjust the center wavelength of the source pulse; and 10 the beam size adjustment system Includes: a plurality of beam size adjustments; and at least one other prism comprising a center wavelength selection 稜鏡. 38. The laser system of claim 37, wherein: the beam size adjustment comprises a coarse bandwidth adjustment and a fine bandwidth adjustment. 39. The laser system of claim 38, wherein: the differential timing system adjusts the differential transmission time to maintain a bandwidth within a selected range of bandwidth. 40. The laser system of claim 39, wherein: the at least one center wavelength selection 稜鏡 comprises a coarse center wavelength selection 稜鏡 and a fine center wavelength selection 稜鏡. 41. The laser system of claim 38, further comprising: an additional center wavelength selective optical element operative to select a center wavelength in conjunction with the center wavelength. The invention as claimed in claim 37, further comprising: a central wavelength selection mechanism comprising a dispersing optical element; and the central wavelength selective 稜鏡 adjusting a beam of light on the dispersing optical element An angle of incidence. The laser system of claim 41, further comprising: a center wavelength selection mechanism comprising a dispersing optical element; and the center wavelength selection 稜鏡 adjusting one of the light beams on the dispersing optical element Angle of incidence. 44. The laser system of claim 37, further comprising: 10 the system selectively adjusting the differential transmission time, including a fine bandwidth control adjustment; and the system controllably adjusting the beam size, Includes a coarse bandwidth control adjustment. 45. The laser system of claim 43, further comprising: 15 the system selectively adjusting the differential transmission time, including a fine bandwidth control adjustment; and the system controllably adjusting the beam size Contains a coarse bandwidth control adjustment. 46. A device comprising: 20 a source laser defining an optical resonant cavity that produces an output; an amplifier laser that receives and amplifies the output of the source laser and provides a laser system output; Metric module for measuring a bandwidth of a laser output light pulse pulse generated by the light source and generating a bandwidth measurement value; 53 200908489 A bandwidth error signal generator receiving the bandwidth measurement value and a bandwidth set point and providing a bandwidth Error signal; a differential timing system that echoes the bandwidth error signal to selectively adjust a differential transmission time between the source laser and the amplifier; and 5 a beam size adjustment system that is controllably adjusted in the species a beam size of a beam within the resonant cavity of the source laser to selectively vary the bandwidth of the source laser output and controllably adjust the center wavelength of the source pulse; and the beam resizing system includes: 10 a plurality of beam size adjustments; a dispersive optical element; and a center wavelength selection 稜鏡, at least partially defining the dispersion optics The angle of incidence of the light beam on one of the members; 15 and a central wavelength selective mirror, which cooperate with at least another prism, the angle of incidence define the dispersion of the light beam on the optical element. 47. The device of claim 46, wherein: the beam size adjustment comprises a coarse bandwidth adjustment and a thin bandwidth adjustment prism. The apparatus of claim 46, wherein: the differential timing system adjusts the differential transmission time to maintain a bandwidth within a selected range of bandwidth. 49. The device of claim 47, wherein: the at least one central wavelength selective prism comprises a coarse center wavelength and a fine center wavelength selection. 50. The apparatus of claim 47, further comprising: an additional central wavelength selective optical element operative in conjunction with the central wavelength selective 以 to select a central wavelength. The device of claim 47, further comprising: a center wavelength selection mechanism comprising a dispersing optical element; and the central wavelength selection 稜鏡 adjusting an incident angle of the beam on the dispersing optical element . 52. The apparatus of claim 47, further comprising: 10 the system selectively adjusting the differential transmission time, including a fine bandwidth control adjustment; and the system controllably adjusting the beam size, including a Thick bandwidth control adjustment. 55