Method and apparatus for replacing a gas mixture in a gas discharge chamber

Abstract

A method for replacing a gas mixture in a gas discharge chamber of a light source includes determining the performance of one or more light sources and / or gas discharge chambers based on performance metrics of the light sources and / or gas discharge chambers; determining the next refilling pressure based on the determined performance and the current operating pressure of the gas discharge chamber; removing the gas mixture from the gas discharge chamber; and filling the gas discharge chamber with the replacement gas mixture up to the next determined refilling pressure. Apparatus for replacing the gas mixture is also disclosed.

Description

Technical Field

[0001] (Cross - reference to Related Applications)

[0001] This application claims priority to U.S. Patent Application No. 63 / 491,990, titled "METHOD AND APPARATUS FOR REPLACING GAS MIXTURE IN A GAS DISCHARGE CHAMBER", filed on March 24, 2023, the entire content of which is incorporated herein by reference.

[0002]

[0002] The present disclosure relates to methods and apparatuses for replacing a gas mixture within a gas discharge chamber of a deep ultraviolet (DUV) light source, such as a power - ring amplifier gas discharge chamber of a DUV light source.

Background Art

[0003]

[0003] One of the gas discharge light sources used in photolithography is called an excimer light source or laser. Typically, an excimer laser uses a mixture of one or more noble gases that may include argon, krypton, or xenon, and a reactive gas that may include fluorine or chlorine. An excimer laser can generate an excimer, i.e., a pseudo - molecule, under appropriate conditions of electrical simulation (the supplied energy) and high pressure (of the gas mixture). An excimer exists only in an excited state. The excited - state excimer causes the generation and amplification of light in the ultraviolet range. An excimer light source for photolithography typically includes a plurality of gas discharge chambers. When the excimer light source is operating, the excimer light source generates a deep ultraviolet (DUV) light beam. The DUV light can include wavelengths, for example, from about 100 nanometers (nm) to about 400 nm.

[0004]

[0004] A DUV light beam from a light source can be sent to a photolithography exposure apparatus. A photolithography exposure apparatus is a machine that generates a desired pattern on a target portion of a substrate, such as a photoresist layer on a semiconductor wafer. The DUV light beam interacts with a projection optics system that projects the DUV light beam onto the photoresist on the wafer via a mask or other imaging apparatus. In this way, one or more layers of a chip design are patterned on the photoresist, and from there, patterns are formed on or inside the wafer, or on or within layers built on the wafer. [Overview of the project]

[0005]

[0005] In some general embodiments, the process of replacing the gas mixture in the gas discharge chamber of a light source includes: determining the performance of one or more light sources and / or gas discharge chambers based on performance metrics of the light sources and / or gas discharge chambers; determining the next refilling pressure based on the determined performance and the current operating pressure of the gas discharge chamber; removing the gas mixture from the gas discharge chamber; and filling the gas discharge chamber with the replacement gas mixture up to the next refilling pressure determined. One or more embodiments may include the following:

[0006]

[0006] The process may further include reducing the gas discharge chamber pressure from a previous refill pressure to the current operating pressure based on one or more performance metrics of the light source and / or gas discharge chamber. The process may further include determining a margin value for increasing the next refill pressure relative to the current operating pressure. If the determined performance indicates that the light source and / or gas discharge chamber is stable, the margin value is a first value; if the determined performance indicates that the light source and / or gas discharge chamber is unstable, the margin value is a second value greater than the first value. The gas discharge chamber may be a power amplifier gas discharge chamber.

[0007]

[0007] The process may further include determining a margin value for increasing the next refill pressure relative to the current operating pressure. Determining the margin value includes comparing one or more light source and / or gas discharge chamber performance metrics to each limit value, setting the margin value to a first value if any of the one or more light source and / or gas discharge chamber performance metrics exceeds one or more limit values, and setting the margin value to a second value if each of the one or more light source and / or gas discharge chamber performance metrics is within one or more limit values. The second value is less than the first value.

[0008]

[0008] The process may further include determining a margin value for increasing the next refill pressure relative to the current operating pressure. The determined performance indicates the stability level of the light source and / or gas discharge chamber, and the determined margin value decreases as the indicated stability level increases.

[0009]

[0009] The process may further include determining a margin value for increasing the next refill pressure relative to the current operating pressure. Determining the margin value includes comparing one or more light source and / or gas discharge chamber performance metrics to each limit value, setting the margin value to a relatively large value if one or more light source and / or gas discharge chamber performance metrics are close to or exceed each limit value, and setting the margin value to a relatively small value if one or more light source and / or gas discharge chamber performance metrics are far from exceeding each limit value.

[0010]

[0010] Determining the next refill pressure may include determining a small margin value if the determined performance indicates that the light source is stable, and a large margin value if the determined performance indicates that the light source is not very stable, and setting the next refill pressure to at least the current operating pressure + margin value. Determining the performance of the light source and / or gas discharge chamber may include comparing one or more light source and / or gas discharge chamber performance metrics to each limit. Determining the performance of the light source and / or gas discharge chamber may include collecting one or more light source and / or gas discharge chamber performance metrics during the standard operation of the light source.

[0011]

[0011] The gas discharge chamber can be a power ring amplifier gas discharge chamber.

[0012]

[0012] In another common embodiment, a gas mixture replacement device associated with a gas discharge chamber in a light source is provided. This device includes (1) a monitoring and control system connected to the light source and configured to (a) determine the current operating pressure value of the gas discharge chamber, (b) determine one or more performance metrics of the light source and / or the gas discharge chamber, and (c) determine the next refill pressure value of the gas discharge chamber based on one or more performance metrics and the current operating pressure value of the gas discharge chamber; (2) a gas mixture removal system configured to remove the gas mixture from the gas discharge chamber; and (3) a gas mixture resupply system connected to the monitoring and control system and configured to refill the gas discharge chamber with the replacement gas mixture up to the determined refill pressure value. Embodiments may include one or more of the following:

[0013]

[0013] The gas discharge chamber can be a power amplifier gas discharge chamber. The power amplifier gas discharge chamber can be a power ring amplifier gas discharge chamber. The light source can be a multi-stage light source. The light source is a multi-stage light source, and one of the stages of the multi-stage light source may be a power amplifier stage. The power amplifier stage includes a gas discharge chamber and a circulating loop optical path passing through the gas discharge chamber. The gas mixture may include argon fluoride (ArF).

[0014]

[0014] The monitoring and control system may further be configured to determine a margin value for increasing the next refill pressure relative to the current operating pressure. Determining the margin value is done by comparing one or more performance metrics of the light source and / or gas discharge chamber to their respective limits, setting the margin value to a first value if any of the one or more light source and / or gas discharge chamber performance metrics exceeds one or more limits, and setting the margin value to a second value if each of the one or more light source and / or gas discharge chamber performance metrics is within one or more limits. The second value is smaller than the first value.

[0015]

[0015] The monitoring and control system may further be configured to determine a margin value for increasing the next refill pressure relative to the current operating pressure. Determining the margin value is done by comparing one or more light source and / or gas discharge chamber performance metrics with each limit value, setting the margin value to a relatively large value if one or more light source and / or gas discharge chamber performance metrics are close to or exceed each limit value, and setting the margin value to a relatively small value if one or more light source and / or gas discharge chamber performance metrics are far from exceeding each limit value.

[0016]

[0016] Details of one or more embodiments will be described in the attached drawings and the following description. Other features will also become apparent from the description and drawings, and from the claims. [Brief explanation of the drawing]

[0017] [Figure 1]

[0017] A block diagram of a gas control device, a related gas discharge chamber, and a light source that supplies an amplified optical beam to an output device. [Figure 2]

[0018] A flowchart of the method of the present disclosure. [Figure 2A]

[0019] A flowchart of a method that can be used in the method of FIG. 2. [Figure 2B]

[0020] A flowchart of a method that can be used in the method of FIG. 2. [Figure 3]

[0021] A block diagram of an embodiment of the output device of FIG. 1, which is a photolithography exposure device. [Figure 4]

[0022] A block diagram of an embodiment of the gas control device, the related gas discharge chamber, and the light source of FIG. 1, showing a two-stage light source. [Figure 5]

[0023] A graph showing a trace representing the pressure of the gas mixture in the gas discharge chamber 150 as a function of time, illustrating an aspect of the present disclosure. [Figure 6]

[0024] A block diagram showing one aspect of the method of the present disclosure. [Figure 7]

[0025] A block diagram showing another aspect of the method of the present disclosure.

Mode for Carrying Out the Invention

[0018]

[0026] Referring to Figure 1, the gas control device 100 is associated with the gas discharge chamber 150 of the light source 160. The light source 160 is configured as part of an optical system (including optical feedback not shown in Figure 1) that supplies an amplified light beam 165 (at least partially generated from the output light beam 153 of the gas discharge chamber 150) to the output device 180. The output device 180 may be, for example, a photolithography exposure apparatus for patterning microelectronic features on a substrate such as a wafer. The gas discharge chamber 150 may be configured as part of a gas discharge stage 155, which can be a power amplifier or a power amplifier stage. The light source 160 may include one or more additional stages, such as a main oscillator (MO) stage (not shown in Figure 1; see Figure 4 described below).

[0019]

[0027] The gas control device 100 includes a monitoring system 140, a gas supply system 170, and a control system 105. The control system 105 includes a gas control module 110 which can be configured to perform a gas filling process, a gas replacement process, and a pressure adjustment process for the gas discharge chamber 150. The gas filling process may be the initial filling of the gas discharge chamber 150 with a gas mixture 151 to prepare the gas discharge chamber 150 and / or the light source 160 for initial operation or initial testing. The gas replacement process may be performed to replace the gas mixture 151 in the gas discharge chamber 150 with a new (fresh) replacement gas mixture 151 after the monitoring system 140 and / or the control system 105 have determined that gas replacement is necessary, in order to restore the operating performance of the gas discharge chamber 150 and / or the light source 160 to standard (or improved) operating performance. The pressure adjustment process is performed after either the gas filling process or the gas replacement process to optimize and / or restore the performance of the gas discharge chamber 150 and / or the light source 160.

[0020]

[0028] In the gas replacement as understood in this specification, for example, all or substantially all of the gas mixture 151 in the gas discharge chamber 150 is replaced by discharging the old gas mixture 151 into a gas damper (not shown), or evacuating the chamber 150 with a vacuum pump (not shown), or purging with a purge gas (not shown), or performing a combination thereof, first emptying the gas discharge chamber 150 via the gas mixture removal system 114, and then refilling the gas discharge chamber 150 with the fresh gas mixture 151 from the gas supply system 170.

[0021]

[0029] The pressure adjustment process is performed to optimize the gas pressure in the gas discharge chamber 150 in order to establish standard operation after the initial filling of the gas mixture or to return to or re - establish the conditions for standard operation after replacement of the gas mixture. During the standard operation mode of the gas discharge chamber 150 following the pressure adjustment process, the optical beam 165 is generated in accordance with the requirements of the output device 180. In various embodiments, the optical beam 165 can be generated in accordance with instructions from or under the control of the output device 180.

\(0022\)

[0030] During the pressure regulation process, after the initial or fresh replacement gas mixture 151 is supplied to the gas discharge chamber 150, the gas control module 110 signals the energy source actuator 154 to generate a discharge or light beam (output light beam) 153 from the gas discharge chamber 150 by supplying energy to the energy source 152 of the gas discharge chamber 150. The discharge or light beam 153 matches the amplified light beam 165, or the amplified light beam 165 can be generated from the discharge or light beam 153 before it is emitted from the light source 160. The gas control module 110 then analyzes the performance of the gas discharge chamber 150 and / or the light source 160 against a set of performance metrics and thresholds or limits specific to the pressure regulation process. The gas control module 110 can perform this analysis by accessing performance parameters tracked or monitored by the monitoring system 140. For example, performance parameters that can be monitored include the energy variation of the light beam 153 output by the gas discharge chamber 150 and / or light source 160, the high voltage setting, the wavelength variation of the light beam 153 output from the gas discharge chamber 150 and / or light source 160, and the wavelength or bandwidth of the light beam 153 output from the gas discharge chamber 150 and / or light source 160.

[0023]

[0031] If the gas control module 110 determines that the discharge chamber 150 and / or the light source 160 are not operating within performance thresholds specific to the pressure regulation process, the gas control module 110 may signal the gas supply system 170 to repeatedly discharge the (fresh) gas mixture 151 from the gas discharge chamber 150 (or, if the pressure regulation process is performed on multiple gas discharge chambers within the light source 160, these chambers) until one or more conditions are met. For example, repeated pressure reduction may continue until one or more performance metrics desirable for standard operation are met, such as performance metrics for power output, wavelength, wavelength bandwidth, etc., or until one or more thresholds or limits for the start of standard operation are reached, such as minimum or maximum pressure. These thresholds or limits may be called recovery setpoints or gas recovery setpoints or limits. Once one or more conditions (of either type) are met or reached, standard operation of the gas discharge chamber 150 and the light source 160 can begin or resume, and the light source 160 can supply the amplified light beam 165 to the output device 180.

[0024]

[0032] In conventional gas control methods and apparatus for gas discharge chambers, such as the gas discharge chamber 150, particularly when the gas discharge chamber 150 is a power amplifier gas discharge chamber, when the gas mixture 151 is first supplied into or replaced in the gas discharge chamber 150, the fresh gas mixture supplied to the gas discharge chamber 150 is supplied up to a predetermined initial refill pressure or a predetermined replacement refill pressure, such as 300 kilopascals (kPa) or higher, allowing for a relatively wide (downward) range of pressure adjustment during the pressure adjustment process. The operating pressure obtained in the gas discharge chamber 150 after the pressure adjustment process is completed (which can be called the "current operating pressure") is set or optimized by the pressure adjustment process for the standard operation of the light source. The current operating pressure thus set can fall within a relatively wide range, such as 220-300 kPa, but in this example, a refill pressure of at least 300 kPa is required. However, such a relatively high refill pressure is not required in all cases. While filling to such relatively high pressures may be necessary for initial filling and some refilling, under appropriate conditions, lower refilling pressures can be used, as described below. Using lower refilling pressures under optimal conditions during gas mixture replacement reduces the amount of gas required for gas mixture replacement, resulting in resource and cost savings.

[0025]

[0033] In accordance with aspects of this disclosure and with reference to Figure 2, a procedure 220 for replacing a gas mixture (e.g., gas mixture 151 in Figure 1) in a gas discharge chamber (e.g., gas discharge chamber 150 in Figure 1) of a light source (e.g., light source 160 in Figure 1) will be illustrated and examined with reference to Figure 1. As shown in Figure 2, the procedure 220 includes: determining the performance of the light source 160 and / or gas discharge chamber 150 based on performance metrics of one or more light sources and / or gas discharge chambers (222); determining the next refill pressure based on the determined performance and the current operating pressure of the gas discharge chamber 150 (223); removing the gas mixture 151 from the gas discharge chamber 150 (224); and filling the gas discharge chamber 150 with the replacement gas mixture up to the next determined refill pressure (225). In the embodiment, the gas discharge chamber and / or light source performance metrics can be measured by the monitoring system 140 and may include metrics such as wavelength, wavelength variability, bandwidth, power, and power variability of the light beam 153 generated by the gas discharge chamber 150 and / or the light beam 165 generated by the light source 160, as well as the operating voltage and other operating conditions of the gas discharge chamber 150. The embodiment may further include one or more of the following:

[0026]

[0034] Procedure 220 may include determining the current operating pressure by reducing it from the previous refilling pressure based on one or more performance metrics of the light source 160 and / or gas discharge chamber 150 specific to the pressure adjustment process, as described above with respect to Figure 1.

[0027]

[0035] With respect to the procedure in Figure 2, a signal indicating that gas mixture replacement is required is received at some point prior to the removal of the gas mixture 151 from the gas discharge chamber 150 (224). The need for refilling may depend on several complex, often unpredictable, variables. These variables include the light source ignition pattern and energy, the service life of the light source module, and other variables and parameters well known to those skilled in the art. If desired, performing refilling on a regular schedule can ensure that no unexpected interruptions in light source operation occur due to the light source reaching its operating limit. In the embodiment, the relative timing of receiving the signal indicating that refilling or gas replacement is required can be at various positions before the removal of the gas mixture begins, including relative timing positions such as positions A, B, and C shown in Figure 2.

[0028]

[0036] Referring to Figure 2A, procedure 223a (223 in Figure 2) can be performed to determine the next refill pressure based on the determined performance and current operating pressure. Procedure 223a includes determining a margin value to increase the next refill pressure relative to the current operating pressure (226a and 216a). If the determined performance indicates that the light source is stable (yes branch of 227), the margin value is set to a first value (228a); if the determined performance indicates that the light source is unstable (no branch of 227), the margin value is set to a second value greater than the first value (229a). The gas discharge chamber 150 in procedure 223a can be a power amplifier gas discharge chamber (i.e., a gas discharge chamber for the power amplifier of the light source, including a gas discharge chamber for the power ring amplifier).

[0029]

[0037] Referring to Figure 2B, in other embodiments, procedure 223b (223 in Figure 2) can be performed to determine the next refill pressure based on the determined performance and current operating pressure. Procedure 223b includes determining a margin value to increase the next refill pressure relative to the current operating pressure (226b and 216b), which is determined by comparing one or more performance metrics to their respective limits (217), setting the margin value to a first value (229a) if any of the one or more performance metrics exceed one or more limits ("no" branch in 218), and setting the margin value to a second value greater than the first value (229b) if none of the one or more performance metrics exceed one or more limits ("yes" branch in 218).

[0030]

[0038] In yet another embodiment, step 220 may include determining a margin value for increasing the next refill pressure relative to the current operating pressure, wherein (1) the determined performance indicates the stability level of the light source 160 and / or gas discharge chamber 150, and (2) the determined margin value decreases as the indicated stability level increases. Step 220 may also include determining a margin value for increasing the next refill pressure relative to the current operating pressure, wherein the determination of the margin value includes (1) comparing one or more performance metrics to each limit value, and (2) setting the margin value to a relatively low value if one or more performance metrics are relatively far from exceeding each limit value, and setting the margin value to a relatively high value if one or more performance metrics are relatively close to exceeding each limit value or exceed each limit value. Furthermore, procedure 220 may include determining a small margin value if the determined performance indicates that the light source 160 and / or gas discharge chamber 150 is stable, and a large margin value if the determined performance indicates that the light source 160 and / or gas discharge chamber 150 is not very stable, and setting the next refill pressure to the current operating pressure + margin value, or at least the current operating pressure + margin value. Determining the performance of the light source 160 and / or discharge chamber 150 may include collecting one or more performance metrics during the standard operation of the light source 160. One or more performance metrics may also be compared to each target during the standard operation of the light source 160. Furthermore, the next refill pressure may be determined and redetermined continuously or substantially continuously during the standard operation of the light source 160, if desired. As described above, the gas discharge chamber 150 in procedure 220 may be a power ring amplifier gas discharge chamber.

[0031]

[0039] Referring again to Figure 1, the gas control device 100 includes a performance monitoring module 115 which can be configured to continuously analyze one or more performance parameters of the light source 160 and / or the gas discharge chamber 150 during the normal operation of the light source 160. The performance analysis can be performed by a performance analyzer PA. As described above, the performance monitoring module 115 can continuously update the margin value based on this analysis, for example by the performance analyzer PA, and the updated margin value can be stored in the control system 105, for example in memory M. In the embodiment, the performance monitoring module 115 can continuously update the next refill pressure itself and store it in memory M, etc. The performance monitoring module 115 can continuously record performance data in memory M, etc., and update the margin value (and next refill pressure) only when gas mixture replacement is requested. Regardless of the specific embodiment, when the gas control module 110 next performs the gas mixture replacement process, a margin value used to set the next refill pressure relative to the current operating pressure is available in or stored within the control system 105, or the next refill pressure value itself is already available in or stored within the control system 105. Therefore, there is no need to manually adjust the margin value or the associated next refill pressure.

[0032]

[0040] In the embodiment, memory M can generally be located within the control system 105, for example, but outside the gas control module 110. Memory M may be accessible from one or more of the modules 110, 115, or other modules not shown within the control system 105. Memory M can be a read-only memory and / or a random-access memory, and can provide a storage device suitable for visibly realizing computer program instructions and data. Memory M may be configured to store information output from each module and / or information received from the monitoring system 140, for use by various modules of the control system 105 during its operation.

[0033]

[0041] In the embodiment, the control system 105 also includes one or more input and / or output devices 109 (such as a keyboard, a touch-enabled device, an audio input device as an input, and audio or video for output), as well as one or more processors 108. Communication between modules 110, 115, and others, and memory M may be direct, via a physical connection (e.g., wired), or wireless connection.

[0034]

[0042] Although the control system 105 is represented as a box in which all components appear to be located in the same place, the control system 105 may consist of components (modules 110, 115, and others not shown) that are physically distant from one another. Each of modules 110, 115, and others not shown may be a dedicated processing system for receiving and analyzing data, or one or more modules may be combined to form a single processing system. Each module may contain or have access to one or more programmable processors 108, and may execute a program of instructions to achieve a desired function by performing actions on input data to produce appropriate outputs. Modules 110, 115, and others may be implemented as digital electronic circuits, computer hardware, firmware, or software.

[0035]

[0043] Referring to Figure 3, in some embodiments, the output device 180 is a photolithography exposure apparatus 380. The exposure apparatus 380 includes an optical mechanism, for example, an illuminator system 381 having one or more condenser lenses, a mask, and an objective mechanism. A light beam 165 travels through the illuminator system 381 and is guided onto a substrate (wafer) 382. The mask may be movable along one or more directions, for example, along the axis of the light beam 165 or in a plane perpendicular to the axis of the light beam 165. The objective mechanism includes, for example, a projection lens, which can transfer an image from the mask to a photoresist on the wafer 382. The illuminator system 381 adjusts the angular range of the light beam 165 incident on the mask. The exposure apparatus 380 may include, among several features, a lithography controller 383 that controls how layers are patterned on the wafer 382. The lithography controller 383 can communicate with a control system 105.

[0036]

[0044] As described above, the light source 160 can be a multi-stage system. In the embodiment shown in Figure 4, the light source 160 is a two-stage light source 460. The light source 460 includes a main oscillator 461A as the first stage and a power amplifier 461B as the second stage. The main oscillator 461A includes a main oscillator gas discharge chamber 450A, and the power amplifier 461B includes a power amplifier gas discharge chamber 450B. The main oscillator gas discharge chamber 450A includes two elongated electrodes as energy sources 452A that provide a pulse energy source to the gas mixture 451A within the chamber 450A. The power amplifier gas discharge chamber 450B includes two elongated electrodes as energy sources 452B that provide a pulse energy source to the gas mixture 451B within the chamber 450B.

[0037]

[0045] The main oscillator 461A provides a pulsed amplified light beam (called a seed light beam) 462 to the power amplifier 461B. The main oscillator gas discharge chamber 450A houses a gas mixture 451A containing a gain medium in which amplification occurs, and the main oscillator 461A includes an optical feedback mechanism such as an optical resonator. The optical resonator is formed between the spectral optics system 463A on one side of the main oscillator gas discharge chamber 450A and the output coupler 464A on the second side of the main oscillator gas discharge chamber 450A. The power amplifier gas discharge chamber 450B houses a gas mixture 451B containing a gain medium in which amplification occurs when seeded with the seed light beam 462 from the main oscillator 461A. If the power amplifier 461B is designed as a regenerative ring resonator, it is described as a power ring amplifier, in which case sufficient optical feedback can be provided from the ring design. Furthermore, the power amplifier 461B may include a beam return (reflector, etc.) 463B that returns the light beam (for example by reflection) to the power amplifier gas discharge chamber 452B to form a circulating loop path (in which the input to the ring amplifier intersects with the output from the ring amplifier), and an output coupler 464B for inputting the seed light beam 462 and outputting the amplified light beam 465. The light beam 153 may be the seed light beam 462 or the amplified light beam 465.

[0038]

[0046] The gas mixtures used in each discharge chamber 450A, 450B (e.g., gas mixtures 451A, 451B) can be combinations of gases suitable for generating an amplified light beam around the required wavelength, bandwidth, and energy. For example, gas mixtures 451A, 451B may include argon fluoride (ArF) emitting light at a wavelength of approximately 193 nm, or krypton fluoride (KrF) emitting light at a wavelength of approximately 248 nm.

[0039]

[0047] Figure 5 shows a graph 590 of arbitrary scales and percentages showing a solid line trace 591 of the pressure P of the gas mixture 151 in the gas discharge chamber 150 as a function of time t. Trace 591 is shown throughout one cycle 592 (its time range is indicated by curly braces 592). Cycle 592 extends from the completion of the initial gas mixture filling 593 or the immediately preceding gas mixture replacement 593, represented by a vertical dashed line 593 indicating the completion point, to the completion of the next gas mixture replacement 594, represented by a vertical dashed line 594 (prior to the next pressure adjustment process, not shown), indicating the completion point.

[0040]

[0048] Continuing to refer to Figure 5, after the completion of filling for the initial gas mixture or the preceding gas mixture replacement (593), the pressure adjustment process 595 (represented by the gradual decrease in pressure in trace 591 and indicated by curly braces 595) gradually reduces the pressure in the gas discharge chamber 150 until the desired performance level is achieved. Once the desired performance level is achieved, the pressure adjustment process stops at the current operating pressure 596. The gas discharge chamber 150 then enters its standard operating period 597.

[0041]

[0049] During normal operation 597, the current operating pressure 596 changes only slightly, and the performance of the gas discharge chamber 150 and / or light source 160, which include this pressure (see Figures 1 and 4), is monitored. Furthermore, during normal operation 597, performance metrics are detected and / or calculated, recorded or otherwise stored, and the performance of the gas discharge chamber 150 and / or light source 160 is evaluated or assessed. As described above, the margin value MV determined by the performance of the gas discharge chamber 150 and / or light source 160, and optionally the next refill pressure, can also be determined or calculated continuously or substantially continuously during normal operation 597.

[0042]

[0050] At the end of the normal operation period 597, if gas mixture replacement is signaled or otherwise requested, the gas mixture 151 in the gas discharge chamber 150 is emptied and / or purged. This is represented by the drop pressure 598. Then, a fresh gas mixture is introduced into the gas discharge chamber until the next refill pressure NRP, which is determined by the current operating pressure 596 + margin value MV, as represented by the rise pressure 599a or 599b. As described above, the margin value MV is determined by evaluating the performance of the gas discharge chamber 150 and / or light source 160 during the normal operation period 597.

[0043]

[0051] In the embodiment, this evaluation can be performed based on the entire duration of normal operation 597, or based only on a time period near the end of the normal operation 597 period, or based on a weighted evaluation in which the weight given to the latter half of the normal operation 597 period is increased or decreased. In the embodiment, the evaluation metrics may use trends and / or variability over the entire duration of normal operation 597 or at any point in time within the period. If the light source 160 and / or discharge chamber 150 are evaluated as relatively stable (or were relatively stable) during standard operation, relatively aggressive gas savings are achieved during the gas mixture replacement process by setting the margin value MV to a relatively small margin value MVa. The margin value MVa determines a relatively small next refill pressure value NRPa for the next gas mixture replacement, which is added to the current operating pressure 596. At a minimum, the relatively small next refill pressure NRPa is less than 300 kPa, i.e., less than the initial filling pressure of the discharge chamber 150, resulting in gas savings compared to filling up to the initial filling pressure. If the light source operation is evaluated as relatively unstable, setting a relatively large margin value MVb achieves relatively less aggressive (i.e., more conservative) gas savings during the gas mixture replacement process. The margin value MVb determines a relatively large next refill pressure value NRPb for the next gas mixture replacement, which is added to the current operating pressure of 596. In the example, the relatively large next refill pressure is also less than 300 kPa, i.e., less than the initial filling pressure of the discharge chamber 150, resulting in gas savings compared to the initial filling pressure, but not as large as in the case of refill pressure NRPa.

[0044]

[0052] The relatively large margin value MVb and the associated relatively large next refill pressure value NRPb provide a larger pressure range, i.e., a larger operating window, for the next pressure adjustment process (not shown) to achieve a subsequent current operating pressure (not shown) according to a recovery setpoint or gas recovery setpoint or limit value for the subsequent normal operating period (not shown). As stated above, Graph 590 is illustrative, non-quantitative, and of substantially arbitrary scales and proportions. (For example, the increasing pressures shown in 599a and 599b of trace 591 do not need to have different slopes. The separation between lines shown in 599a and 599b is used to better illustrate the principles of this disclosure. Similarly, in practice, pressure changes over time during gas mixture replacement are not linear everywhere.)

[0045]

[0053] As described above, the determination of the margin value MV can have either a binary or more continuous result. This is shown in Figures 6 and 7. Referring to Figure 6, the performance analyzer 630 (e.g., performance analyzer PA in the gas controller 110 in Figure 1) receives a signal 631 to replace the gas mixture 151 in the gas discharge chamber 150, and also receives one or more performance metrics 632 of the gas discharge chamber 150 and / or the light source 160. If the analyzed performance is relatively low, the performance analyzer PA triggers a conservative gas-saving mode 633 (upper option). In this mode, the next refill pressure is set to the current operating pressure + a relatively large (conservative) margin value (634). If the analyzed performance is relatively high, the performance analyzer PA triggers a conservative gas-saving mode 635 (lower option). In this mode, the next refill pressure is set to the current operating pressure + a relatively small (conservative) margin value (636) to achieve greater gas savings in the next gas replacement.

[0046]

[0054] Referring to Figure 7, the performance analyzer 730 (such as the performance analyzer PA in the gas controller 110 in Figure 1) receives a signal 731 to replace the gas mixture 151 in the gas discharge chamber 150, and also receives one or more performance metrics 732 of the gas discharge chamber 150 and / or the light source 160. The margin value is set such that the higher the analyzed performance, the lower the margin value (the more aggressive) (737). If the performance of the gas discharge chamber 150 and / or the light source 160 is more stable, the next refill pressure value is set based on the current operating pressure and margin value so that greater gas savings are achieved during the next gas mixture replacement (738).

[0047]

[0055] Embodiments of the present invention can be further described in the following numbered clauses. 1. A method for replacing the gas mixture in the gas discharge chamber of a light source, Determining the performance of a light source and / or gas discharge chamber based on one or more light source and / or gas discharge chamber performance metrics, The next refill pressure is determined based on the determined performance and the current operating pressure of the gas discharge chamber, To remove the gas mixture from the gas discharge chamber, The gas discharge chamber is filled with the displacement gas mixture until the next determined refill pressure, A method that includes this. 2. The method according to Clause 1, further comprising reducing the gas discharge chamber pressure from a previous refilling pressure to the current operating pressure based on one or more performance metrics of the light source and / or gas discharge chamber. 3. The method according to Clause 1, further comprising determining a margin value for increasing the next refilling pressure relative to the current operating pressure, wherein the margin value is a first value if the determined performance indicates that the light source and / or gas discharge chamber is stable, and the margin value is a second value greater than the first value if the determined performance indicates that the light source and / or gas discharge chamber is unstable. 4. The gas discharge chamber is a power amplifier gas discharge chamber, as described in Clause 3. 5. Further including determining a margin value for increasing the next refilling pressure relative to the current operating pressure, determining the margin value is: Comparing the performance metrics of one or more light sources and / or gas discharge chambers to their respective limit values, If one or more of the performance metrics of one or more light sources and / or gas discharge chambers exceed one or more limit values, the margin value shall be set to the first value, If one or more light sources and / or gas discharge chamber performance metrics are within one or more limit values, the margin value shall be set to a second value, Including the second value being less than the first value, as described in Clause 1. 6. The method according to Clause 1, further comprising determining a margin value for increasing the next refilling pressure relative to the current operating pressure, wherein the determined performance indicates the stability level of the light source and / or gas discharge chamber, and the determined margin value decreases as the indicated stability level increases. 7. The gas discharge chamber is a power amplifier gas discharge chamber, as described in Clause 6. 8. Further including determining a margin value for increasing the next refilling pressure relative to the current operating pressure, determining the margin value is: Comparing the performance metrics of one or more light sources and / or gas discharge chambers to their respective limit values, If one or more light sources and / or gas discharge chamber performance metrics are close to or exceed their respective limits, the margin value should be set to a relatively large value; if one or more light sources and / or gas discharge chamber performance metrics are relatively far from exceeding their respective limits, the margin value should be set to a relatively small value. including, The method described in Article 1. 9. Determining the next refilling pressure is A small margin value is determined if the determined performance indicates that the light source is stable, and a large margin value is determined if the determined performance indicates that the light source is not very stable. The next refilling pressure should be set to at least the current operating pressure plus a margin value. The method described in Clause 1, including the method described in Clause 1. 10. Determining the next refilling pressure is A small margin value is determined if the determined performance indicates that the light source is stable, and a large margin value is determined if the determined performance indicates that the light source is not very stable. The next refilling pressure should be set to the current operating pressure plus a margin value. The method described in Clause 1, including the method described in Clause 1. 11. Determining the performance of a light source and / or gas discharge chamber is the method according to Clause 1, which includes comparing one or more light source and / or gas discharge chamber performance metrics with each limit. 12. Determining the performance of a light source and / or gas discharge chamber is the method according to Clause 1, which includes collecting one or more light source and / or gas discharge chamber performance metrics during the standard operation of the light source. 13. The gas discharge chamber is a power ring amplifier gas discharge chamber, as described in Clause 1. 14. A gas mixture replacement device associated with a gas discharge chamber in a light source, A monitoring and control system connected to a light source, configured to determine the current operating pressure value of the gas discharge chamber, determine one or more performance metrics of the light source and / or the gas discharge chamber, and determine the next refill pressure value of the gas discharge chamber based on one or more performance metrics and the current operating pressure value of the gas discharge chamber, A gas mixture removal system configured to remove a gas mixture from a gas discharge chamber, A gas mixture resupply system connected to a monitoring and control system and configured to fill the gas discharge chamber with a replacement gas mixture up to a determined refill pressure value, A gas mixture replacement apparatus equipped with the following features. 15. The gas discharge chamber is a power amplifier gas discharge chamber, as described in Clause 14. 16. The power amplifier gas discharge chamber is a power ring amplifier gas discharge chamber, as described in Clause 15. 17. The device described in Clause 15, wherein the light source is a multi-stage light source. 18. The apparatus according to Clause 15, wherein the light source is a multi-stage light source, one of the stages of the multi-stage light source is a power amplifier stage, the power amplifier stage includes a gas discharge chamber and a circulating loop optical path through the gas discharge chamber, and the gas mixture includes argon fluoride (ArF). 19. The monitoring and control system is further configured to determine a margin value for increasing the next refilling pressure relative to the current operating pressure, the determination of which is done by comparing one or more performance metrics of the light source and / or gas discharge chamber to their respective limit values, setting the margin value to a first value if any of the one or more light source and / or gas discharge chamber performance metrics exceeds one or more limit values, and setting the margin value to a second value if each of the one or more light source and / or gas discharge chamber performance metrics is within one or more limit values, the apparatus as described in Clause 15, wherein the second value is smaller than the first value. 20. The apparatus as described in Clause 15, wherein the monitoring and control system is further configured to determine a margin value for increasing the next refilling pressure relative to the current operating pressure, and the determination of the margin value is performed by comparing one or more light source and / or gas discharge chamber performance metrics with each limit value, setting the margin value to a relatively large value if one or more light source and / or gas discharge chamber performance metrics are close to or exceed each limit value, and setting the margin value to a relatively small value if one or more light source and / or gas discharge chamber performance metrics are far from exceeding each limit value.

[0048]

[0056] The above-described embodiments and other embodiments are within the scope of the following claims.

Claims

1. A method for replacing the gas mixture in the gas discharge chamber of a light source, The performance of the light source and / or gas discharge chamber is determined based on performance metrics of one or more light sources and / or gas discharge chambers, The next refill pressure is determined based on the performance determined above and the current operating pressure of the gas discharge chamber, To remove the gas mixture from the gas discharge chamber, The gas discharge chamber is filled with the displacement gas mixture up to the next refill pressure determined above, A method that includes this.

2. The method according to claim 1, further comprising reducing the gas discharge chamber pressure from a previous refilling pressure to the current operating pressure based on one or more performance metrics of the light source and / or the gas discharge chamber.

3. The method according to claim 1, further comprising determining a margin value for increasing the next refilling pressure with respect to the current operating pressure, wherein the determined performance indicates that the light source and / or the gas discharge chamber is stable, the margin value is a first value, and the determined performance indicates that the light source and / or the gas discharge chamber is unstable, the margin value is a second value greater than the first value.

4. The method according to claim 3, wherein the gas discharge chamber is a power amplifier gas discharge chamber.

5. The method further includes determining a margin value that increases the next refilling pressure relative to the current operating pressure, and determining the margin value is The performance metrics of one or more light sources and / or gas discharge chambers are compared with their respective limit values, If any of the one or more light sources and / or gas discharge chamber performance metrics exceeds one or more limit values, the margin value is set to a first value. If each of the one or more light sources and / or gas discharge chamber performance metrics is within one or more limit values, the margin value is set to a second value. The method according to claim 1, including the second value being smaller than the first value.

6. The method according to claim 1, further comprising determining a margin value for increasing the next refilling pressure with respect to the current operating pressure, wherein the determined performance indicates the stability level of the light source and / or the gas discharge chamber, and the determined margin value decreases as the indicated stability level increases.

7. The method according to claim 6, wherein the gas discharge chamber is a power amplifier gas discharge chamber.

8. The method further includes determining a margin value that increases the next refilling pressure relative to the current operating pressure, and determining the margin value is The performance metrics of one or more light sources and / or gas discharge chambers are compared with their respective limit values, If the performance metrics of one or more light sources and / or gas discharge chambers are close to or exceed the respective limit values, the margin value is set to a relatively large value; if the performance metrics of one or more light sources and / or gas discharge chambers are far from exceeding the respective limit values, the margin value is set to a relatively small value. including, The method according to claim 1.

9. Determining the next refilling pressure is: A small margin value is determined if the determined performance indicates that the light source is stable, and a large margin value is determined if the determined performance indicates that the light source is not very stable. The next refilling pressure is set to at least the current operating pressure plus the margin value, The method according to claim 1, including the method described in claim 1.

10. Determining the next refilling pressure is: A small margin value is determined if the determined performance indicates that the light source is stable, and a large margin value is determined if the determined performance indicates that the light source is not very stable. The next refilling pressure is set to the current operating pressure plus the margin value, The method according to claim 1, including the method described in claim 1.

11. The method according to claim 1, wherein determining the performance of the light source and / or gas discharge chamber includes comparing one or more light source and / or gas discharge chamber performance metrics with each limit.

12. The method according to claim 1, wherein determining the performance of the light source and / or gas discharge chamber comprises collecting performance metrics of one or more light sources and / or gas discharge chambers during the standard operation of the light source.

13. The method according to claim 1, wherein the gas discharge chamber is a power ring amplifier gas discharge chamber.

14. A gas mixture replacement device associated with a gas discharge chamber in a light source, A monitoring and control system connected to the light source, configured to determine the current operating pressure value of the gas discharge chamber, determine one or more performance metrics of the light source and / or the gas discharge chamber, and determine the next refill pressure value of the gas discharge chamber based on the one or more performance metrics and the current operating pressure value of the gas discharge chamber, A gas mixture removal system configured to remove the gas mixture from the gas discharge chamber, A gas mixture resupply system connected to the monitoring and control system and configured to fill the gas discharge chamber with the replacement gas mixture up to the determined refill pressure value, A gas mixture replacement apparatus equipped with the following features.

15. The apparatus according to claim 14, wherein the gas discharge chamber is a power amplifier gas discharge chamber.

16. The apparatus according to claim 15, wherein the power amplifier gas discharge chamber is a power ring amplifier gas discharge chamber.

17. The apparatus according to claim 15, wherein the light source is a multi-stage light source.

18. The apparatus according to claim 15, wherein the light source is a multi-stage light source, one of the stages of the multi-stage light source is a power amplifier stage, the power amplifier stage includes the gas discharge chamber and a circulating loop optical path passing through the gas discharge chamber, and the gas mixture includes argon fluoride (ArF).

19. The monitoring and control system is further configured to determine a margin value for increasing the next refilling pressure with respect to the current operating pressure, the determination of which is done by comparing one or more performance metrics of the light source and / or gas discharge chamber with their respective limit values, setting the margin value to a first value if any of the one or more performance metrics of the light source and / or gas discharge chamber exceeds one or more limit values, and setting the margin value to a second value if each of the one or more performance metrics of the light source and / or gas discharge chamber is within one or more limit values, wherein the second value is smaller than the first value, the apparatus according to claim 15.

20. The apparatus according to claim 15, wherein the monitoring and control system is further configured to determine a margin value for increasing the next refilling pressure with respect to the current operating pressure, the determination of the margin value is performed by comparing the performance metrics of one or more light sources and / or gas discharge chambers with each limit value, setting the margin value to a relatively large value if the performance metrics of one or more light sources and / or gas discharge chambers are close to or exceed each limit value, and setting the margin value to a relatively small value if the performance metrics of one or more light sources and / or gas discharge chambers are far from exceeding each limit value.

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