Power supply for pulsed laser, pulsed laser device, and method for manufacturing electronic devices

Abstract

The pulse energy of pulsed laser light is stabilized. [Solution] The power supply for the pulse laser comprises a step-up transformer, a first magnetic pulse compression circuit that transfers the charge of a first transfer capacitor connected to the secondary side of the step-up transformer to a second transfer capacitor, a second magnetic pulse compression circuit that transfers the charge of the second transfer capacitor to a peaking capacitor, a reset circuit, and a series circuit of a resistor and an inductor connected in parallel to the peaking capacitor. The resistance value R of the resistor is 100Ω or more and 1000Ω or less. When the capacitance of the peaking capacitor is Cp, the resonant angular frequency when the charge is transferred from the second transfer capacitor to the peaking capacitor is ω, the repetition frequency is Rep, and the time required for magnetic reset is Tm, the inductance L of the inductor satisfies the following two equations. ((ωL) 2 +R 2 ) 1 / 2 >1 / ωCp, L ≤ (1 / Rep - Tm) × R / 2

Description

[Technical Field]

[0001] This disclosure relates to a power supply for a pulsed laser, a pulsed laser apparatus, and a method for manufacturing an electronic device. [Background technology]

[0002] In recent years, semiconductor lithography equipment has been required to improve resolution as semiconductor integrated circuits become smaller and more integrated. Therefore, efforts are being made to shorten the wavelength of light emitted from lithography light sources. For example, gas laser equipment used for lithography includes KrF excimer laser equipment that outputs laser light with a wavelength of approximately 248 nm, and ArF excimer laser equipment that outputs laser light with a wavelength of approximately 193 nm.

[0003] The spectral linewidth of the spontaneously emitted light from KrF and ArF excimer laser systems is broad, ranging from 350 to 400 pm. Therefore, when a projection lens is constructed using a material that transmits ultraviolet light, such as KrF and ArF laser light, chromatic aberration may occur. As a result, the resolution may decrease. Thus, it is necessary to narrow the spectral linewidth of the laser light output from a gas laser system until chromatic aberration is negligible. For this reason, gas laser systems may be equipped with a Line Narrowing Module (LNM) containing narrowing elements (such as etalons or gratings) within the laser resonator to narrow the spectral linewidth. A gas laser system with a narrowed spectral linewidth is called a narrowband gas laser system. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Summary of Japanese Patent Publication No. 2010-073948

[0005] A pulse laser power supply according to one aspect of the present disclosure includes a step-up transformer through which a pulse current from a main capacitor flows on the primary side, a first transfer capacitor connected to the secondary side of the step-up transformer, a first magnetic switch connected to the first transfer capacitor, a first magnetic pulse compression circuit that transfers the charge of the first transfer capacitor to a second transfer capacitor, a second transfer capacitor, a second magnetic switch connected to the second transfer capacitor, a second magnetic pulse compression circuit that transfers the charge of the second transfer capacitor to a peaking capacitor, and a step-up transformer The system comprises a first magnetic switch, a second magnetic switch, a reset circuit including a reset winding that reverse-excites the cores to perform a magnetic reset, and a series circuit of a resistor and an inductor connected in parallel to the peaking capacitor, wherein the resistance value R of the resistor is 100Ω or more and 1000Ω or less, the capacitance of the peaking capacitor is Cp, the resonant angular frequency when charge is transferred from the second transfer capacitor to the peaking capacitor is ω, the repetition frequency is Rep, and the time required for the magnetic reset is Tm, and the inductance L of the inductor satisfies the following two equations. ((ωL) 2 +R 2 ) 1 / 2 >1 / ωCp L ≤ (1 / Rep - Tm) × R / 2

[0006] A pulse laser apparatus according to one aspect of the present disclosure includes a step-up transformer to which a pulse voltage taken from a main capacitor is applied to the primary side, a first transfer capacitor connected to the secondary side of the step-up transformer, a first magnetic switch connected to the first transfer capacitor, a first magnetic pulse compression circuit for transferring the charge of the first transfer capacitor to a second transfer capacitor, a second transfer capacitor, a second magnetic switch connected to the second transfer capacitor, a second magnetic pulse compression circuit for transferring the charge of the second transfer capacitor to a peaking capacitor, a step-up transformer, a first magnetic switch, The laser chamber comprises a second magnetic switch, a reset circuit including a reset winding that performs a magnetic reset by reverse-exciting the core, a series circuit of a resistor and an inductor connected in parallel to the peaking capacitor, and a pair of electrodes connected to the peaking capacitor. The resistance R of the resistor is between 100Ω and 1000Ω, the capacitance of the peaking capacitor is Cp, the resonant angular frequency during charge transfer from the second transfer capacitor to the peaking capacitor is ω, the repetition frequency is Rep, and the time required for magnetic reset is Tm. The inductance L of the inductor satisfies the following two equations. ((ωL) 2 +R 2 ) 1 / 2 >1 / ωCp L ≤ (1 / Rep - Tm) × R / 2

[0007] A method for manufacturing an electronic device according to one aspect of the present disclosure includes a boost transformer to which a pulse voltage taken out from a main capacitor is applied to the primary side, a first transfer capacitor connected to the secondary side of the boost transformer, and a first magnetic switch connected to the first transfer capacitor. A first magnetic pulse compression circuit that transfers the charge of the first transfer capacitor to the second transfer capacitor, a second transfer capacitor, and a second magnetic switch connected to the second transfer capacitor. A second magnetic pulse compression circuit that transfers the charge of the second transfer capacitor to the peaking capacitor, a reset circuit including a reset winding that demagnetizes the cores of the boost transformer, the first magnetic switch, and the second magnetic switch to perform magnetic reset, and a series circuit of a resistor and an inductor connected in parallel to the peaking capacitor. A laser chamber including a pair of electrodes connected to the peaking capacitor inside. The resistance value R of the resistor is 100 Ω or more and 1000 Ω or less. Let the capacitance of the peaking capacitor be Cp, the resonance angular frequency at the time of transferring the charge from the second transfer capacitor to the peaking capacitor be ω, the repetition frequency be Rep, and the required time for magnetic reset be Tm. The inductance L of the inductor satisfies the following two equations: ((ωL) 2 +R 2 ) 1 / 2 >1 / ωCp L≦(1 / Rep-Tm)×R / 2 Generating pulsed laser light by a pulsed laser device, outputting the pulsed laser light to an exposure device, and exposing the pulsed laser light on a photosensitive substrate in the exposure device to manufacture an electronic device.

Brief Description of the Drawings

[0008] Some embodiments of the present disclosure will be described below by way of example only with reference to the accompanying drawings. [Figure 1] FIG. 1 shows the configuration of an exposure system in a comparative example. [Figure 2] FIG. 2 shows the configuration of the pulsed laser device shown in FIG. 1. [Figure 3]FIG. 3 shows the configuration of the pulse power module shown in FIG. 2. [Figure 4] FIG. 4 is a graph showing the change in the voltage applied between the electrodes inside the laser chamber in the comparative example. [Figure 5] FIG. 5 shows the configuration of the pulse laser device in the first embodiment. [Figure 6] FIG. 6 shows the configuration of the pulse power module in the first embodiment. [Figure 7] FIG. 7 is a graph showing the change in the voltage applied between the electrodes inside the laser chamber in the first embodiment. [Figure 8] FIG. 8 shows the configuration of the pulse laser device in the second embodiment. Embodiment

[0009] <Content> 1. Comparative Example 1.1 Exposure System 1.2 Exposure Device 200 1.3 Pulse Laser Device 100 1.3.1 Configuration 1.3.2 Operation 1.4 Pulse Power Module 13 1.4.1 Configuration 1.4.2 Operation 2. Problems of the Comparative Example 3. Pulse Power Module 13a Including Resistance R1 and Inductor L1 3.1 Configuration 3.2 Operation 3.3 Parameters 3.4 Function 4. Pulse Laser Device 100b Including Amplifier 120 4.1 Configuration 4.2 Operation 4.3 Function 5. Others 5.1 Processor 130 5.2 Supplementary

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. The embodiments described below are examples of the disclosure and are not intended to limit the scope of this disclosure. Furthermore, not all configurations and operations described in each embodiment are necessarily essential to the configurations and operations of this disclosure. The same reference numerals are used for identical components, and redundant descriptions are omitted.

[0011] 1. Comparative Example 1.1 Exposure System Figure 1 shows the configuration of the exposure system in the comparative example. The comparative example in this disclosure is a configuration that the applicant recognizes as being known only to the applicant, and is not a known example acknowledged by the applicant.

[0012] The exposure system includes a pulsed laser device 100 and an exposure device 200. In Figure 1, the pulsed laser device 100 is shown in a simplified form. The pulsed laser device 100 is configured to output pulsed laser light LB toward the exposure device 200.

[0013] 1.2 Exposure apparatus 200 As shown in Figure 1, the exposure apparatus 200 includes an illumination optical system 201 and a projection optical system 202. The illumination optical system 201 illuminates the reticle pattern of a reticle (not shown) placed on a reticle stage RT with pulsed laser light LB incident from a pulsed laser apparatus 100. The projection optical system 202 reduces and projects the pulsed laser light LB that has passed through the reticle onto a workpiece (not shown) placed on a workpiece table WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0014] The exposure apparatus 200 exposes the workpiece to a pulsed laser beam LB that reflects the reticle pattern by synchronously moving the reticle stage RT and the workpiece table WT in parallel. After transferring the reticle pattern to the semiconductor wafer through the exposure process described above, an electronic device can be manufactured by going through several processes.

[0015] 1.3 Pulse laser device 100 1.3.1 Configuration Figure 2 shows the configuration of the pulsed laser device 100 shown in Figure 1. The pulsed laser device 100 includes a laser oscillator 110, a processor 130, and a monitor module 140. The laser oscillator 110 includes a laser chamber 10, a charger 12, a pulsed power module 13, a narrowband module 14, and an output mirror 15. The output mirror 15 and the grating 14c included in the narrowband module 14 constitute an optical resonator. The configuration of the processor 130 will be described later.

[0016] The laser chamber 10 includes windows 10a and 10b, which are positioned in the optical path of the optical resonator. The laser chamber 10 is configured to contain a laser gas containing components of the laser gain medium and includes a pair of electrodes 11a and 11b for applying a voltage to the laser gain medium. The laser gain medium is, for example, ArF, KrF, etc.

[0017] The direction of propagation of the pulsed laser beam LB1 output from the output mirror 15 is defined as the Z direction. The direction in which electrodes 11a and 11b face each other is defined as the V direction or -V direction. The Z direction and the V direction are perpendicular to each other, and the direction perpendicular to both of these is defined as the H direction or -H direction. Figure 2 shows the configuration of the pulsed laser device 100 as seen in the -H direction.

[0018] The pulse power module 13 includes a main capacitor C0 and a switch SW, which will be described later with reference to Figure 3. The main capacitor C0 is connected to the charger 12, and the switch SW is connected to the processor 130. The output terminals of the pulse power module 13 are connected to electrodes 11a and 11b.

[0019] The narrowband module 14 includes a prism 14b and a grating 14c. The prism 14b is positioned in the optical path of light emitted from the window 10a. The prism 14b is rotatable about an axis parallel to the V direction by a rotating stage (not shown). The grating 14c is positioned in the optical path of light transmitted through the prism 14b. The output mirror 15 is composed of a partial reflection mirror.

[0020] The monitor module 140 includes a beam splitter 41 and an optical sensor 42. The beam splitter 41 is positioned in the optical path of the pulsed laser light LB1 output from the output mirror 15, and is configured to transmit a portion of the pulsed laser light LB1 with high transmittance to become pulsed laser light LB, while reflecting the other portion. The optical sensor 42 is positioned in the optical path of the pulsed laser light LB1 reflected by the beam splitter 41. The optical sensor 42 is configured to measure the central wavelength and pulse energy of the pulsed laser light LB1.

[0021] 1.3.2 Operation The processor 130 receives data for the target value of the center wavelength, data for the target value of the pulse energy, and a trigger signal from the exposure apparatus 200. Based on the target value of the center wavelength, the processor 130 sends an initial setting signal to the narrowband module 14. Based on the target value of the pulse energy, the processor 130 sends an initial setting signal for the charging voltage to the charger 12. The processor 130 also sends an oscillation trigger signal to the switch SW of the pulse power module 13 based on the trigger signal.

[0022] The charger 12 charges the main capacitor C0 based on the charging voltage set by the processor 130. The switch SW turns ON when it receives an oscillation trigger signal from the processor 130. When the switch SW is ON, the pulse power module 13 generates a pulsed high voltage from the electrical energy charged in the main capacitor C0 and applies this high voltage between electrodes 11a and 11b.

[0023] When a high voltage is applied between electrodes 11a and 11b, a discharge occurs between them. The energy of this discharge excites the laser gas inside the laser chamber 10, causing it to shift to a higher energy level. When the excited laser gas then shifts to a lower energy level, it emits light with a wavelength corresponding to the energy level difference.

[0024] Light generated inside the laser chamber 10 is emitted outside the laser chamber 10 through windows 10a and 10b. The light emitted from window 10a has its beam width expanded in a plane parallel to the HZ plane by prism 14b. The light that passes through prism 14b is incident on grating 14c.

[0025] Light incident on the grating 14c is reflected by multiple grooves in the grating 14c and diffracted in a direction corresponding to the wavelength of the light. By matching the incident angle of the light incident on the grating 14c with the diffraction angle of the diffracted light of the desired wavelength, the wavelength of the diffracted light returned from the grating 14c to the prism 14b is selected. As the orientation of the prism 14b changes due to the rotation angle of the rotating stage, the incident angle of the light incident on the grating 14c changes, and the wavelength selected by the narrowband module 14 changes. The prism 14b reduces the beam width of the diffracted light returned from the grating 14c in the HZ plane and returns that light to the inside of the laser chamber 10 through the window 10a.

[0026] The output mirror 15 transmits a portion of the light emitted from the window 10b and outputs it, while reflecting the other portion back into the laser chamber 10.

[0027] In this way, the light emitted from the laser chamber 10 travels back and forth between the narrowband module 14 and the output mirror 15. This light is amplified each time it passes through the discharge space between electrodes 11a and 11b, and narrowed in bandwidth each time it is reflected back by the narrowband module 14. The laser-oscillating and narrowed-band light is then output from the output mirror 15 as pulsed laser light LB1 and incident on the exposure apparatus 200 as pulsed laser light LB.

[0028] The processor 130 receives the measured value of the center wavelength from the monitor module 140 and provides feedback control to the narrowband module 14 based on the target value of the center wavelength and the measured value of the center wavelength. The processor 130 also receives the measured value of the pulse energy from the monitor module 140 and provides feedback control to the charging voltage of the charger 12 based on the target value of the pulse energy and the measured value of the pulse energy.

[0029] 1.4 Pulse Power Module 13 1.4.1 Configuration Figure 3 shows the configuration of the pulse power module 13 shown in Figure 2. In addition to the main capacitor C0 and switch SW, the pulse power module 13 further includes a step-up transformer TC1, magnetic switches SR0, SR1, and SR2, first and second transfer capacitors C1 and C2, and a reset circuit RC. Magnetic switches SR1 and SR2 correspond to the first and second magnetic switches in this disclosure, respectively. The output terminals of the pulse power module 13 are connected to a peaking capacitor Cp1 and electrodes 11a and 11b, which are connected in parallel to each other. The peaking capacitor Cp1 and electrodes 11a and 11b are contained within the laser chamber 10.

[0030] Magnetic switches SR0 to SR2 all contain saturable reactors. Each of the magnetic switches SR0 to SR2 is configured to switch to low impedance when the time integral of the voltage applied across it reaches a predetermined value determined by the characteristics of each magnetic switch.

[0031] One terminal of magnetic switch SR0 is connected to one terminal of main capacitor C0. The other terminal of main capacitor C0 is connected to the reference potential. The other terminal of magnetic switch SR0 is connected to the reference potential via the primary winding of step-up transformer TC1 and switch SW, which are connected in series with each other.

[0032] One terminal of the magnetic switch SR1 is connected to a reference potential via the secondary winding of the step-up transformer TC1, and is also connected to one terminal of the first transfer capacitor C1. The other terminal of the first transfer capacitor C1 is also connected to the reference potential. In other words, the secondary winding of the step-up transformer TC1 and the first transfer capacitor C1 are connected in parallel. The first transfer capacitor C1 and the magnetic switch SR1 constitute the first magnetic pulse compression circuit PC1.

[0033] The other terminal of magnetic switch SR1 is connected to one terminal of magnetic switch SR2, and also to one terminal of the second transfer capacitor C2. The other terminal of the second transfer capacitor C2 is connected to a reference potential. The second transfer capacitor C2 and magnetic switch SR2 constitute the second magnetic pulse compression circuit PC2.

[0034] The other terminal of the magnetic switch SR2 is connected to one terminal of the peaking capacitor Cp1 and electrode 11a. The other terminal of the peaking capacitor Cp1 and electrode 11b are connected to a reference potential.

[0035] The reset circuit RC includes a DC power supply E, a reactor L0 connected in series with the DC power supply E, and reset windings LR0, TR1, LR1, and LR2. The cores of the reset windings LR0, LR1, LR2, and TR1 are common to the cores of the magnetic switches SR0, SR1, and SR2, and the step-up transformer TC1, respectively.

[0036] 1.4.2 Operation When the main capacitor C0 is charged by the charger 12 and the switch SW is turned on after receiving an oscillation trigger signal from the processor 130, the voltage across the main capacitor C0 is applied to the magnetic switch SR0. When the time integral of the voltage applied to the magnetic switch SR0 reaches a predetermined value, the magnetic switch SR0 turns on, and a pulsed current flows from the main capacitor C0 to the magnetic switch SR0, the primary winding of the step-up transformer TC1, and the switch SW.

[0037] When current flows through the primary winding of the step-up transformer TC1, electromagnetic induction causes a current to flow through the secondary winding of the step-up transformer TC1, corresponding to the winding ratio of the step-up transformer TC1. When current flows through the secondary winding of the step-up transformer TC1, the first transfer capacitor C1 is charged, and the voltage across the first transfer capacitor C1 is applied to the magnetic switch SR1. When the time integral value of the voltage applied to the magnetic switch SR1 reaches a predetermined value, the magnetic switch SR1 turns on, and a pulsed current flows through the magnetic switch SR1.

[0038] When current flows through magnetic switch SR1, the charge from the first transfer capacitor C1 is transferred to the second transfer capacitor C2, charging the second transfer capacitor C2, and the voltage across the second transfer capacitor C2 is applied to magnetic switch SR2. The pulse width of the current used to charge the second transfer capacitor C2 is shorter than the pulse width of the current used to charge the first transfer capacitor C1, resulting in a higher voltage. When the time integral value of the voltage applied to magnetic switch SR2 reaches a predetermined value, magnetic switch SR2 turns on, and a pulsed current flows through magnetic switch SR2.

[0039] When current flows through the magnetic switch SR2, the charge from the second transfer capacitor C2 is transferred to the peaking capacitor Cp1, and the peaking capacitor Cp1 is charged. The pulse width of the current used to charge the peaking capacitor Cp1 is shorter than the pulse width of the current used to charge the second transfer capacitor C2, resulting in a higher voltage.

[0040] When the voltage across the peaking capacitor Cp1 reaches the breakdown voltage of the laser gas, a discharge occurs between electrodes 11a and 11b. This excites the laser gas, causing the laser to oscillate. Switch SW switches at a predetermined repetition frequency, and a pulsed laser beam LB is output at that frequency.

[0041] After the peaking capacitor Cp1 is charged, the magnetic switches SR0~SR2 and the core of the step-up transformer TC1 are magnetically reset. To perform the magnetic reset, the DC power supply E in the reset circuit RC is used to reverse-excite the reset windings LR0, LR1, LR2, and TR1 by supplying current. The direction of the current flowing through the windings of the magnetic switches SR0~SR2 and the step-up transformer TC1 during pulse generation is opposite to the direction of the current flowing through the reset windings LR0, LR1, LR2, and TR1 during the magnetic reset.

[0042] 2. Issues with the Comparative Example Figure 4 is a graph showing the change in voltage applied between electrodes 11a and 11b inside the laser chamber 10 in the comparative example. The horizontal axis represents time t, and the vertical axis represents the voltage Vcp across the peaking capacitor Cp1. The voltage Vcp is equivalent to the voltage between electrodes 11a and 11b.

[0043] At time t1, a negative high-voltage pulse is generated, initiating discharge between electrodes 11a and 11b, after which the voltage Vcp reverses and rises. At time t2, once the magnetic reset of the magnetic switches SR0, SR1, and SR2 and the core of the step-up transformer TC1 is complete, the voltage Vcp then oscillates and decays.

[0044] To improve the semiconductor production efficiency of the exposure apparatus 200, it may be necessary to increase the repetition frequency of the pulsed laser beam LB. When the repetition frequency of the pulsed laser beam LB is set to, for example, 6 kHz, the discharge period is 166.7 μs. However, if the repetition frequency of the pulsed laser beam LB is increased, the voltage Vcp may not decay sufficiently before the next discharge. For example, if the next discharge occurs at time t3 or earlier, variations may occur in the discharge voltage, which may cause variations in the pulse energy of the pulsed laser beam LB.

[0045] The embodiments described below relate to stabilizing the pulse energy of the pulsed laser beam LB by suppressing fluctuations in the voltage Vcp after a magnetic reset.

[0046] 3. Pulse power module 13a including resistor R1 and inductor L1 3.1 Configuration Figure 5 shows the configuration of the pulse laser apparatus 100a in the first embodiment. The pulse laser apparatus 100a differs from the pulse laser apparatus 100 in the comparative example in that it includes a pulse power module 13a instead of a pulse power module 13. The pulse power module 13a is an example of a power supply for a pulse laser in this disclosure.

[0047] Figure 6 shows the configuration of the pulse power module 13a in the first embodiment. In the pulse power module 13a, the other terminal of the magnetic switch SR2, that is, the terminal connected to the peaking capacitor Cp1, is connected to a reference potential via a series circuit of resistor R1 and inductor L1. That is, the series circuit of resistor R1 and inductor L1 is connected in parallel with the peaking capacitor Cp1.

[0048] 3.2 Operation Figure 7 is a graph showing the change in voltage applied between electrodes 11a and 11b inside the laser chamber 10 in the first embodiment. The horizontal axis represents time t, and the vertical axis represents the voltage Vcp across the peaking capacitor Cp1. The change in voltage Vcp up to time t2 is the same as in the comparative example.

[0049] At time t2, after the magnetic reset of the magnetic switches SR0, SR1, and SR2 and the core of the step-up transformer TC1 is complete, the voltage Vcp oscillates and decays, but the oscillation of voltage Vcp decays earlier than in the comparative example shown by the dashed line. This is because current flows through resistor R1 and energy is consumed as a result of the oscillation of voltage Vcp.

[0050] If a large current flows through resistor R1 during the charge transfer from the second transfer capacitor C2 to the peaking capacitor Cp1, the peaking capacitor Cp1 may not be sufficiently charged. The charge transfer from the second transfer capacitor C2 to the peaking capacitor Cp1 will be referred to as "main transfer" below. By providing an inductor L1 with sufficient inductance L, the flow of a large pulse current through resistor R1 during the main transfer is suppressed.

[0051] 3.3 Parameters It is desirable to sufficiently reduce the oscillation of the voltage Vcp between discharges. For example, it is desirable to reduce the amplitude of the oscillation to 20V or less before the next discharge. In the configuration of the pulse power module 13a shown in Figure 6, the inductance L of the inductor L1 was set to 0.1mH, and simulations were performed while changing the resistance value R of the resistor R1 to calculate the amplitude of the voltage Vcp oscillation at the time of the next discharge. As a result, the resistance value R of the resistor R1 required to reduce the amplitude at the time of the next discharge to 20V or less was between 100Ω and 1000Ω.

[0052] The lower limit of the inductance L of inductor L1 is set as follows, so that the impedance Zcom of the series circuit of resistor R1 and inductor L1 during main transfer is greater than the impedance Zcp of peaking capacitor Cp1 during main transfer.

[0053] First, let C2 be the capacitance of the second transfer capacitor C2, and Cp be the capacitance of the peaking capacitor Cp1. Then, the combined capacitance C of the second transfer capacitor C2 and the peaking capacitor Cp1 can be calculated using equation (1). C = 1 / (1 / C² + 1 / Cp) ... (1)

[0054] The resonant period τ during main transmission is calculated using equation (2). τ = 2π × (LC) 1 / 2 ...(2)

[0055] The resonant angular frequency ω during main transmission is calculated using equation (3). ω = 2π / τ ···(3)

[0056] The impedance Zcp of the peaking capacitor Cp1 during main transfer is calculated using equation (4). Zcp = 1 / ωCp ···(4)

[0057] The impedance Zcom of the series circuit of resistor R1 and inductor L1 during main transfer is calculated using equation (5). Zcom=((ωL) 2 +R 2 ) 1 / 2 ...(5)

[0058] By setting the lower limit of the inductance L to satisfy the following equation (6), the flow of a large pulse current through the resistor R1 during main transfer is suppressed. Zcom>Zcp ···(6)

[0059] By using equation (7) instead of equation (6), the large pulse current flowing through resistor R1 during main transfer is further suppressed. Zcom>10×Zcp ···(7)

[0060] On the other hand, if the inductance L of inductor L1 is too large, the damping effect of voltage Vcp oscillations will be insufficient, so the upper limit of the inductance L should be set as follows.

[0061] Let Rep be the repetition frequency of the pulsed laser beam LB, and Tm be the time required for magnetic reset. The time required Tm is the time from the discharge timing shown at time t1 in Figure 7 to the completion timing of the magnetic reset shown at time t2. By setting the inductance L to a value that satisfies equation (8), the damping of the voltage Vcp oscillation is promoted, and the amplitude of the next discharge can be reduced to 20V or less. L ≤ (1 / Rep - Tm) × R / 2 ···(8)

[0062] By using equation (9) instead of equation (8), the amplitude of the next discharge can be further reduced. L≦(1 / Rep-Tm)×R / 10 (9)

[0063] The inductance L is preferably between 0.1 mH and 10.7 mH. The magnetic reset time Tm is preferably between 40 μs and 80 μs. Resistor R1 may contain multiple resistive elements. Inductor L1 may contain multiple inductive elements. It is preferable that both resistor R1 and inductor L1 are immersed in insulating oil.

[0064] 3.4 Effect According to the first embodiment, the pulse power module 13a includes a step-up transformer TC1 through which pulse current from a main capacitor C0 flows to the primary side, a first magnetic pulse compression circuit PC1, a second magnetic pulse compression circuit PC2, a reset circuit RC, and a series circuit of a resistor R1 and an inductor L1.

[0065] The first magnetic pulse compression circuit PC1 includes a first transfer capacitor C1 connected to the secondary side of the step-up transformer TC1, and a magnetic switch SR1 connected to the first transfer capacitor C1, and transfers the charge of the first transfer capacitor C1 to the second transfer capacitor C2. The second magnetic pulse compression circuit PC2 includes a second transfer capacitor C2 and a magnetic switch SR2 connected to the second transfer capacitor C2, and transfers the charge of the second transfer capacitor C2 to the peaking capacitor Cp1. The reset circuit RC includes reset windings TR1, LR1, and LR2 that perform a magnetic reset by reverse-exciting the cores of the step-up transformer TC1, magnetic switch SR1, and magnetic switch SR2. A series circuit of resistor R1 and inductor L1 is connected in parallel to the peaking capacitor Cp1. The resistance R of resistor R1 is between 100Ω and 1000Ω, the capacitance of peaking capacitor Cp1 is Cp, the resonant angular frequency during charge transfer from the second transfer capacitor C2 to peaking capacitor Cp1 is ω, the repetition frequency is Rep, and the time required for magnetic reset is Tm. Then the inductance L of inductor L1 satisfies the following two equations. ((ωL) 2 +R 2 ) 1 / 2 >1 / ωCp L ≤ (1 / Rep - Tm) × R / 2

[0066] According to this, by setting the resistance value R and inductance L in the series circuit of resistor R1 and inductor L1 connected in parallel to the peaking capacitor Cp1 to an appropriate range, the oscillation of the voltage Vcp after magnetic reset is sufficiently suppressed, and the large pulse current flowing through resistor R1 when charge is transferred from the second transfer capacitor C2 to the peaking capacitor Cp1 is suppressed. By suppressing the oscillation of voltage Vcp, the pulse energy of the pulsed laser beam LB can be stabilized. In addition, by suppressing the pulse current flowing through resistor R1, losses during charge transfer can be suppressed.

[0067] In other respects, the first embodiment is the same as the comparative example.

[0068] 4. Pulse laser apparatus 100b including amplifier 120 4.1 Configuration Figure 8 shows the configuration of the pulsed laser device 100b in the second embodiment. The pulsed laser device 100b differs from the pulsed laser device 100a in that it includes an amplifier 120 between the laser oscillator 110 and the monitor module 140.

[0069] The amplifier 120 includes a laser chamber 20, a charger 22, a pulse power module 23a, a rear mirror 24, and an output mirror 25. The rear mirror 24 and the output mirror 25 constitute an optical resonator. The rear mirror 24 is a partially reflective mirror with a higher reflectivity than the output mirror 25 and is positioned in the optical path of the pulsed laser beam LB1. The configurations of the laser chamber 20, charger 22, pulse power module 23a, and output mirror 25 are the same as those of the laser chamber 10, charger 12, pulse power module 13a, and output mirror 15, respectively. The pulse power module 23a is an example of a power supply for a pulsed laser in this disclosure. The configurations of the windows 20a and 20b and the pair of electrodes 21a and 21b included in the laser chamber 20 are the same as those of windows 10a and 10b and electrodes 11a and 11b, respectively.

[0070] 4.2 Operation The pulsed laser beam LB1 output from the laser oscillator 110 enters the laser chamber 20 via the rear mirror 24 and window 20a. The timing of the input of the oscillation trigger signal to the pulse power module 23a is controlled so that a discharge begins between electrodes 21a and 21b at the same time that the pulsed laser beam LB1 enters the laser chamber 20. The pulsed laser beam LB2 output from the output mirror 25 enters the monitor module 140 and enters the exposure apparatus 200 as pulsed laser beam LB.

[0071] 4.3 Effect According to the second embodiment, the laser oscillator 110 and the amplifier 120 each include pulse power modules 13a and 23a, and each of the pulse power modules 13a and 23a includes a series circuit of a resistor R1 and an inductor L1 connected in parallel to a peaking capacitor Cp1, and the resistance value R and inductance L are set to an appropriate range.

[0072] According to this, variations in the discharge voltage Vcp are suppressed in both the laser oscillator 110 and the amplifier 120. As a result, variations in the discharge voltage are suppressed, and therefore variations in the pulse energy of the pulsed laser light LB2 output from the output mirror 25 are suppressed.

[0073] Furthermore, variations in the voltage Vcp during discharge can cause a shift in the discharge timing, but by suppressing variations in the voltage Vcp during discharge, the discharge timing can be controlled with high precision. Therefore, the timing at which the pulsed laser light LB1 output from the laser oscillator 110 is incident on the amplifier 120 and the timing at which the discharge starts in the amplifier 120 can be controlled with high precision.

[0074] In other respects, the second embodiment is the same as the first embodiment.

[0075] 5. Others 5.1 Processor 130 The processor 130 may be physically configured in hardware form to perform the various operations included in this disclosure. For example, the processor 130 may be a computer including a memory storing a control program that defines the various operations, and a processing unit that executes the control program. The control program may be stored in a single memory, or it may be stored in multiple physically separate memories, and the various operations may be defined by the control program as a collection of these memories. The processing unit may be a general-purpose processing unit such as a CPU, or a purpose-specific processing unit such as a GPU.

[0076] Furthermore, the processor 130 may be programmed in software form to perform the various processes included in this disclosure. For example, the processor 130 may have functions for performing the various processes implemented in a dedicated device such as an ASIC or a programmable device such as an FPGA.

[0077] The various processes included in this disclosure may be performed by one computer, one dedicated device, or one programmable device, or by the cooperation of multiple computers, multiple dedicated devices, or multiple programmable devices located physically separately. The various processes may be performed by at least two combinations of one or more computers, one or more dedicated devices, and one or more programmable devices.

[0078] 5.2 Supplement The above description is intended to be illustrative, not restrictive. Therefore, it will be apparent to those skilled in the art that modifications can be made to the embodiments of this disclosure without departing from the claims. It will also be apparent to those skilled in the art that the embodiments of this disclosure can be used in combination.

[0079] Terms used throughout this specification and the claims should be interpreted as "non-limiting" unless otherwise specified. For example, terms such as "includes," "have," "equip," and "possess" should be interpreted as "not excluding the existence of components other than those described." Also, the modifier "one" should be interpreted as "at least one" or "one or more." Furthermore, the term "at least one of A, B, and C" should be interpreted as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C." In addition, it should be interpreted as including combinations of these with anything other than "A," "B," and "C."

Claims

1. A step-up transformer through which pulse current from the main capacitor flows to the primary side, A first magnetic pulse compression circuit includes a first transfer capacitor connected to the secondary side of the step-up transformer, and a first magnetic switch connected to the first transfer capacitor, which transfers the charge of the first transfer capacitor to a second transfer capacitor. A second magnetic pulse compression circuit includes the second transfer capacitor and a second magnetic switch connected to the second transfer capacitor, and transfers the charge of the second transfer capacitor to a peaking capacitor. A reset circuit including a reset winding that reverse-excites the cores of the step-up transformer, the first magnetic switch, and the second magnetic switch to perform a magnetic reset, A series circuit of a resistor and an inductor is connected in parallel to the aforementioned peaking capacitor, Equipped with, The resistance value R of the aforementioned resistor is between 100Ω and 1000Ω. When the capacitance of the peaking capacitor is Cp, the resonant angular frequency during charge transfer from the second transfer capacitor to the peaking capacitor is ω, the repetition frequency is Rep, and the time required for the magnetic reset is Tm, the inductance L of the inductor satisfies the following two equations: ((ωL) ２ +R ２ ) １／２ >1 / ωCp L≦(1 / Rep-Tm)×R / 2 Power supply for pulsed lasers.

2. A power supply for a pulsed laser according to claim 1, The inductance L satisfies the following equation: ((ωL) ２ +R ２ ) １／２ >10 / ωCp Power supply for pulsed lasers.

3. A power supply for a pulsed laser according to claim 1, The inductance L satisfies the following equation: L≦(1 / Rep-Tm)×R / 10 Power supply for pulsed lasers.

4. A power supply for a pulsed laser according to claim 1, The inductance L satisfies the following two equations: ((ωL) ２ +R ２ ) １／２ >10 / ωCp L≦(1 / Rep-Tm)×R / 10 Power supply for pulsed lasers.

5. A power supply for a pulsed laser according to claim 1, The time Tm required for the magnetic reset is 40 μs or more and 80 μs or less. Power supply for pulsed lasers.

6. A power supply for a pulsed laser according to claim 1, The aforementioned resistor includes a plurality of resistive elements. Power supply for pulsed lasers.

7. A power supply for a pulsed laser according to claim 1, The inductor includes a plurality of inductor elements. Power supply for pulsed lasers.

8. A power supply for a pulsed laser according to claim 1, The resistor and the inductor are immersed in insulating oil. Power supply for pulsed lasers.

9. A step-up transformer through which pulse current from the main capacitor flows to the primary side, A first magnetic pulse compression circuit includes a first transfer capacitor connected to the secondary side of the step-up transformer, and a first magnetic switch connected to the first transfer capacitor, which transfers the charge of the first transfer capacitor to a second transfer capacitor. A second magnetic pulse compression circuit includes the second transfer capacitor and a second magnetic switch connected to the second transfer capacitor, and transfers the charge of the second transfer capacitor to a peaking capacitor. A reset circuit including a reset winding that reverse-excites the cores of the step-up transformer, the first magnetic switch, and the second magnetic switch to perform a magnetic reset, A series circuit of a resistor and an inductor is connected in parallel to the aforementioned peaking capacitor, A laser chamber containing a pair of electrodes connected to the peaking capacitor, Equipped with, The resistance value R of the aforementioned resistor is between 100Ω and 1000Ω. When the capacitance of the peaking capacitor is Cp, the resonant angular frequency during charge transfer from the second transfer capacitor to the peaking capacitor is ω, the repetition frequency is Rep, and the time required for the magnetic reset is Tm, the inductance L of the inductor satisfies the following two equations: ((ωL) ２ +R ２ ) １／２ >1 / ωCp L≦(1 / Rep-Tm)×R / 2 Pulsed laser device.

10. A pulsed laser apparatus according to claim 9, The inductance L satisfies the following equation: ((ωL) ２ +R ２ ) １／２ >10 / ωCp Pulsed laser device.

11. A pulsed laser apparatus according to claim 9, The inductance L satisfies the following equation: L≦(1 / Rep-Tm)×R / 10 Pulsed laser device.

12. A pulsed laser apparatus according to claim 9, The inductance L satisfies the following two equations: ((ωL) ２ +R ２ ) １／２ >10 / ωCp L≦(1 / Rep-Tm)×R / 10 Pulsed laser device.

13. A pulsed laser apparatus according to claim 9, The time Tm required for the magnetic reset is 40 μs or more and 80 μs or less. Pulsed laser device.

14. A pulsed laser apparatus according to claim 9, The aforementioned resistor includes a plurality of resistive elements. Pulsed laser device.

15. A pulsed laser apparatus according to claim 9, The inductor includes a plurality of inductor elements. Pulsed laser device.

16. A pulsed laser apparatus according to claim 9, The resistor and the inductor are immersed in insulating oil. Pulsed laser device.

17. A method for manufacturing electronic devices, A step-up transformer through which pulse current from the main capacitor flows to the primary side, A first magnetic pulse compression circuit includes a first transfer capacitor connected to the secondary side of the step-up transformer, and a first magnetic switch connected to the first transfer capacitor, which transfers the charge of the first transfer capacitor to a second transfer capacitor. A second magnetic pulse compression circuit includes the second transfer capacitor and a second magnetic switch connected to the second transfer capacitor, and transfers the charge of the second transfer capacitor to a peaking capacitor. A reset circuit including a reset winding that reverse-excites the cores of the step-up transformer, the first magnetic switch, and the second magnetic switch to perform a magnetic reset, A series circuit of a resistor and an inductor is connected in parallel to the aforementioned peaking capacitor, A laser chamber containing a pair of electrodes connected to the peaking capacitor, Equipped with, The resistance value R of the aforementioned resistor is between 100Ω and 1000Ω. When the capacitance of the peaking capacitor is Cp, the resonant angular frequency during charge transfer from the second transfer capacitor to the peaking capacitor is ω, the repetition frequency is Rep, and the time required for the magnetic reset is Tm, the inductance L of the inductor satisfies the following two equations: ((ωL) ２ +R ２ ) １／２ >1 / ωCp L≦(1 / Rep-Tm)×R / 2 A pulsed laser device generates pulsed laser light, The pulsed laser light is output to the exposure apparatus, To manufacture the aforementioned electronic device, the pulsed laser light is exposed onto a photosensitive substrate in the exposure apparatus. A method for manufacturing electronic devices, including the following.

18. A method for manufacturing an electronic device according to claim 17, The inductance L satisfies the following equation: ((ωL) ２ +R ２ ) １／２ >10 / ωCp A method for manufacturing electronic devices.

19. A method for manufacturing an electronic device according to claim 17, The inductance L satisfies the following equation: L≦(1 / Rep-Tm)×R / 10 A method for manufacturing electronic devices.

20. A method for manufacturing an electronic device according to claim 17, The inductance L satisfies the following two equations: ((ωL) ２ +R ２ ) １／２ >10 / ωCp L≦(1 / Rep-Tm)×R / 10 A method for manufacturing electronic devices.

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