Exposure system and method for manufacturing electronic device

Abstract

This exposure system is provided with: an illumination optical system that illuminates a photomask with a pulsed laser light including a plurality of center wavelengths; and a projection optical system that illuminates the photosensitive substrate with the pulsed laser light that has passed through the photomask and projects an image of the photomask, the position of a first pupil, which is a pupil of the illumination optical system, from a reference position in conjugate relationship with a second pupil, which is a pupil of the projection optical system, the objective of the present invention is to shift in a direction in which a magnification telecentric error is used to reduce a shift in an imaging position caused by lateral chromatic aberration on a photosensitive substrate.

Description

Technical Field

[0001] The present disclosure relates to an exposure system and a method for manufacturing an electronic device. Background Art

[0002] In recent years, in semiconductor exposure apparatuses, with the miniaturization and high integration of semiconductor integrated circuits, an improvement in resolution has been required. Therefore, the shortening of the wavelength of light emitted from an exposure light source has been promoted. For example, as a gas laser device for exposure, a KrF excimer laser device that emits laser light with an output wavelength of about 248 nm and an ArF excimer laser device that emits laser light with an output wavelength of about 193 nm are used.

[0003] The spectral line widths of the spontaneous oscillation light of the KrF excimer laser device and the ArF excimer laser device are as wide as 350 pm to 400 pm. Therefore, when a projection lens is made of a material that transmits ultraviolet light such as KrF and ArF lasers, chromatic aberration may occur. As a result, the resolution may decrease. Therefore, it is necessary to narrow the spectral line width of the laser output from the gas laser device to a level where chromatic aberration can be ignored. Therefore, in the laser resonator of the gas laser device, in order to narrow the spectral line width, a line narrowing module (LNM) including a line narrowing element (etalon, grating, etc.) is sometimes provided. A gas laser device whose spectral line width has been narrowed is called a line-narrowed laser device.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: International Publication No. 2021 / 110343 Summary of the Invention

[0007] In one aspect of the present disclosure, an exposure system includes: an illumination optical system that illuminates a photomask with pulsed laser light including a plurality of central wavelengths; and a projection optical system that illuminates a photosensitive substrate with the pulsed laser light that has passed through the photomask, and projects an image of the photomask. The position of a first pupil, which is a pupil of the illumination optical system, is shifted from a reference position that is conjugate to a second pupil, which is a pupil of the projection optical system, in a direction that reduces the shift of the imaging position caused by lateral chromatic aberration on the photosensitive substrate by using a magnification telecentric error.

[0008] In one aspect of the present disclosure, a method for manufacturing an electronic device includes the following steps: using an exposure system, exposing a pulsed laser on a photosensitive substrate to manufacture the electronic device, the exposure system including: an illumination optical system that illuminates a pulsed laser including a plurality of central wavelengths onto a photomask; and a projection optical system that illuminates the pulsed laser that has passed through the photomask onto the photosensitive substrate, and the position of the image of the projection photomask, as the first pupil of the pupil of the illumination optical system, is shifted from a reference position that is conjugate to the second pupil that is the pupil of the projection optical system in a direction that uses a magnification telecentric error to reduce the shift of the imaging position caused by lateral chromatic aberration on the photosensitive substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Hereinafter, as an example only, several embodiments of the present disclosure will be described with reference to the drawings.

[0010] Figure 1 Schematically shows the structure of the exposure system in the comparative example.

[0011] Figure 2 Schematically shows the structure of the laser device.

[0012] Figure 3 Is a graph showing a periodic wavelength change.

[0013] Figure 4 Shows the cumulative spectrum of a pulsed laser including a plurality of central wavelengths.

[0014] Figure 5 Shows the photosensitive substrate exposed by the exposure device.

[0015] Figure 6 Is a diagram for explaining the case where the position of the scanning field of the photosensitive substrate changes with respect to the position of the beam cross-section of the pulsed laser.

[0016] Figure 7 Is a diagram for explaining the case where the position of the scanning field of the photosensitive substrate changes with respect to the position of the beam cross-section of the pulsed laser.

[0017] Figure 8 Is a diagram for explaining the case where the position of the scanning field of the photosensitive substrate changes with respect to the position of the beam cross-section of the pulsed laser.

[0018] Figure 9 Is a schematic diagram of the projection optical system included in the exposure device.

[0019] Figure 10 Shows the case where the image formed on the photosensitive substrate by Figure 9 the shown projection optical system is deformed.

[0020] Figure 11It is a schematic diagram of an optical system including a part of an illumination optical system and a telecentric projection optical system on both sides.

[0021] Figure 12 Shows Figure 11 The change of the chief ray in the case where the pupil of the illumination optical system is shifted in the direction of the optical axis in the optical system shown.

[0022] Figure 13 It is a diagram for explaining Figure 12 The situation where the image formed on the photosensitive substrate by the optical system shown changes.

[0023] Figure 14 It is a diagram for explaining Figure 12 The situation where the image formed on the photosensitive substrate by the optical system shown changes.

[0024] Figure 15 It is a diagram for explaining Figure 12 The situation where the image formed on the photosensitive substrate by the optical system shown changes.

[0025] Figure 16 Shows Figure 11 The change of the chief ray in the case where the pupil of the illumination optical system in the optical system shown is shifted in the direction opposite to Figure 12 The opposite direction.

[0026] Figure 17 It is a diagram for explaining Figure 16 The situation where the image formed on the photosensitive substrate by the optical system shown changes.

[0027] Figure 18 It is a diagram for explaining Figure 16 The situation where the image formed on the photosensitive substrate by the optical system shown changes.

[0028] Figure 19 It is a diagram for explaining Figure 16 The situation where the image formed on the photosensitive substrate by the optical system shown changes.

[0029] Figure 20 It is a schematic diagram showing a part of the marginal rays of the pulsed laser incident on the worktable when longitudinal chromatic aberration and lateral chromatic aberration occur.

[0030] Figure 21 Schematically shows Figure 20 The imaging regions of the light of each wavelength of the pulsed laser shown.

[0031] Figure 22 It is a cross-sectional view showing the resist profile when developing the photosensitive substrate exposed with the pulsed laser shown using Figure 20 And Figure 21 The pulsed laser shown.

[0032] Figure 23 Shows the use of Figure 20 and Figure 21 The offset of the image on the photosensitive substrate after scanning exposure with the pulsed laser shown.

[0033] Figure 24 Is a schematic diagram showing a part of the chief ray of the pulsed laser incident on the stage when a magnification telecentric error occurs.

[0034] Figure 25 Schematically shows Figure 24 The imaging region of the light of each wavelength of the pulsed laser shown.

[0035] Figure 26 Schematically shows Figure 24 The imaging region of the light of each wavelength of the pulsed laser shown when lateral chromatic aberration is considered.

[0036] Figure 27 Is a schematic diagram showing a part of the chief ray of the pulsed laser incident on the stage when a magnification telecentric error in the opposite direction to Figure 24 occurs.

[0037] Figure 28 Schematically shows Figure 27 The imaging region of the light of each wavelength of the pulsed laser shown.

[0038] Figure 29 Schematically shows Figure 27 The imaging region of the light of each wavelength of the pulsed laser shown when lateral chromatic aberration is considered.

[0039] Figure 30 Schematically shows the structure of the exposure system in the first embodiment.

[0040] Figure 31 Conceptually shows the first example of an illumination optical system capable of moving the position of the pupil.

[0041] Figure 32 Conceptually shows the second example of an illumination optical system capable of moving the position of the pupil.

[0042] Figure 33 Conceptually shows the third example of an illumination optical system capable of moving the position of the pupil.

[0043] Figure 34 Is a flowchart showing the process of correcting magnification distortion in the first embodiment.

[0044] Figure 35 Schematically shows the structure of the exposure system in the second embodiment.

[0045] Figure 36 This is a flowchart showing the process of generating a correction table in the second embodiment.

[0046] Figure 37 This shows an example of the correction table stored in the non-volatile memory.

[0047] Figure 38 This is a flowchart showing the process of correcting magnification distortion in the second embodiment.

[0048] Figure 39 This schematically shows the structure of the exposure system in the third embodiment.

[0049] Figure 40 This is a flowchart showing the process of correcting magnification distortion in the third embodiment. Detailed Description of the Invention

[0050] <Content>

[0051] 1. Comparative Example

[0052] 1.1 Exposure Device 200

[0053] 1.1.1 Structure

[0054] 1.1.2 Operation

[0055] 1.2 Laser Device 100

[0056] 1.2.1 Structure

[0057] 1.2.2 Operation

[0058] 1.3 Narrowbanding Module 14

[0059] 1.3.1 Structure

[0060] 1.3.2 Operation

[0061] 1.4 Periodic Wavelength Change and Cumulative Spectrum

[0062] 1.5 Scanning Exposure

[0063] 1.6 Magnification Distortion

[0064] 1.7 Chromatic Aberration

[0065] 1.8 Magnification Chromatic Aberration

[0066] 1.9 Magnification Telecentric Error

[0067] 1.10 Problems of the Comparative Example

[0068] 2. Exposure System with the Position of the Pupil IP of the Illumination Optical System 201 Shifted

[0069] 2.1 Principle

[0070] 2.2 Structure

[0071] 2.3 Operation (Correction of Magnification Distortion)

[0072] 2.4 Function

[0073] 3. Exposure System for Determining the Position of the Pupil IP of the Illumination Optical System 201 Based on Spectral Parameters

[0074] 3.1 Structure

[0075] 3.2 Action

[0076] 3.2.1 Generation of Correction Table

[0077] 3.2.2 Correction of Magnification Distortion

[0078] 3.3 Function

[0079] 4. Exposure System Including a Measurement Unit 303b Separated from the Exposure Device 200

[0080] 4.1 Structure

[0081] 4.2 Operation (Correction of Magnification Distortion)

[0082] 4.3 Function

[0083] 5. Others

[0084] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, not all of the structures and operations described in each embodiment are essential to the structures and operations of the present disclosure. Furthermore, the same reference numerals are assigned to the same components, and repeated descriptions are omitted.

[0085] 1. Comparative Example

[0086] Figure 1 The structure of the exposure system in the comparative example is schematically shown. The comparative example of the present disclosure is a method known only to the applicant and not a publicly known example recognized by the applicant himself. Figure 1 The X-axis, Y-axis, and Z-axis perpendicular to each other are shown. The exposure system includes a laser device 100 and an exposure device 200. The laser device 100 is shown schematically Figure 1 in

[0087] The laser device 100 includes a laser control processor 130. The laser control processor 130 is a processing device including a memory 132 storing a control program and a CPU (central processing unit) 131 executing the control program. The laser control processor 130 is specially configured or programmed to execute various processes included in the present disclosure. The laser device 100 is configured to output pulsed laser light to the exposure device 200.

[0088] 1.1 Exposure device 200

[0089] 1.1.1 Structure

[0090] As Figure 1 shown, the exposure device 200 includes an illumination optical system 201, a projection optical system 202, and an exposure control processor 210. The illumination optical system 201 illuminates a photomask (not shown) disposed on the mask stage MS with the pulsed laser light incident from the laser device 100.

[0091] The projection optical system 202 illuminates a workpiece (not shown) disposed on the workpiece stage WT with the pulsed laser light that has passed through the photomask, and projects an image of the photomask. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a resist film.

[0092] The exposure control processor 210 is a processing device including a memory 212 storing a control program and a CPU 211 executing the control program. The exposure control processor 210 corresponds to the processor in the present disclosure. The exposure control processor 210 is specially configured or programmed to execute various processes included in the present disclosure. The exposure control processor 210 uniformly controls the exposure device 200 and exchanges various parameters and various signals with the laser control processor 130.

[0093] 1.1.2 Operation

[0094] The exposure control processor 210 sends various parameters and a trigger signal to the laser control processor 130, where the various parameters include a target short wavelength λ1, a target long wavelength λ2, and a voltage command value. The laser control processor 130 controls the laser device 100 based on these parameters and signals. The target short wavelength λ1 corresponds to the first wavelength in the present disclosure, and the target long wavelength λ2 corresponds to the second wavelength in the present disclosure.

[0095] The exposure control processor 210 causes the mask stage MS and the workpiece stage WT to move synchronously in opposite directions parallel to each other. Thereby, the workpiece is exposed with the pulsed laser light reflecting the mask pattern of the photomask.

[0096] Through photolithography as described above, the mask pattern is transferred to the photosensitive substrate. Then, through multiple processes, electronic devices can be manufactured.

[0097] 1.2 Laser device 100

[0098] 1.2.1 Structure

[0099] Figure 2 The structure of the laser device 100 is schematically shown. In Figure 2 , the exposure device 200 is shown simplified. The laser device 100 includes, in addition to the laser control processor 130, a laser chamber 10, a pulse power module (PPM) 13, a narrowbanding module 14, an output coupling mirror 15, and a monitoring module 17. The narrowbanding module 14 and the output coupling mirror 15 constitute an optical resonator.

[0100] The laser chamber 10 is arranged on the optical path of the optical resonator. Windows 10a and 10b are provided in the laser chamber 10. The laser chamber 10 has discharge electrodes 11a and a non-illustrated discharge electrode paired therewith inside. For example, a laser gas is enclosed in the laser chamber 10, and the laser gas includes argon or krypton as a noble gas, fluorine as a halogen gas, neon as a buffer gas, and the like.

[0101] The pulse power module 13 includes a non-illustrated switch and is connected to a non-illustrated charger.

[0102] The narrowbanding module 14 includes prisms 41 to 43, a grating 53, and a mirror 63. The details of the narrowbanding module 14 will be described later.

[0103] The output coupling mirror 15 is constituted by a partial mirror. A beam splitter 16 that transmits a part of the pulsed laser with a high transmittance and reflects the other part is arranged on the optical path of the pulsed laser output from the output coupling mirror 15. A monitoring module 17 is arranged on the optical path of the pulsed laser reflected by the beam splitter 16.

[0104] 1.2.2 Operation

[0105] The laser control processor 130 acquires various parameters including a target short wavelength λ1, a target long wavelength λ2, and a voltage command value from the exposure control processor 210. The laser control processor 130 sends a control signal to the narrowbanding module 14 according to the target short wavelength λ1 and the target long wavelength λ2.

[0106] The laser control processor 130 receives a trigger signal from the exposure control processor 210. The laser control processor 130 sends an oscillation trigger signal based on the trigger signal to the pulse power module 13. The switch included in the pulse power module 13 becomes on when receiving the oscillation trigger signal from the laser control processor 130. When the switch becomes on, the pulse power module 13 generates a pulsed high voltage according to the electric energy charged in the charger and applies the high voltage to the discharge electrode 11a.

[0107] When a high voltage is applied to the discharge electrode 11a, discharge occurs in the discharge space between the discharge electrode 11a and a discharge electrode (not shown). By the energy of this discharge, the laser gas in the laser chamber 10 is excited and transferred to a high energy level. When the excited laser gas transfers to a low energy level later, light with a wavelength corresponding to the energy level difference is emitted.

[0108] The light generated in the laser chamber 10 is emitted to the outside of the laser chamber 10 through the windows 10a and 10b. The light emitted from the window 10a is incident on the narrowbanding module 14. The light near the desired wavelength among the light incident on the narrowbanding module 14 is reflected back to the laser chamber 10 by the narrowbanding module 14.

[0109] The output coupler mirror 15 allows a part of the light emitted from the window 10b to pass through and be output, and reflects the other part back to the laser chamber 10.

[0110] In this way, the light emitted from the laser chamber 10 reciprocates between the narrowbanding module 14 and the output coupler mirror 15. This light is amplified each time it passes through the discharge space in the laser chamber 10. In addition, this light is narrowed each time it is reflected back by the narrowbanding module 14, becoming light with a steep wavelength distribution, and the wavelength distribution has a center wavelength at a part of the range based on the selected wavelength of the narrowbanding module 14. The light that has undergone such laser oscillation and narrowing is output as pulsed laser light from the output coupler mirror 15.

[0111] The monitoring module 17 measures the center wavelength of the pulsed laser and sends the measured wavelength to the laser control processor 130. The laser control processor 130 performs feedback control on the narrowbanding module 14 based on the measured wavelength. The pulsed laser that has passed through the beam splitter 16 is incident on the exposure device 200.

[0112] 1.3 Narrowbanding module 14

[0113] 1.3.1 Structure

[0114] The prisms 41 to 43 are arranged in ascending order of their numbers on the optical path of the light beam emitted from the window 10a. The prism 43 can be rotated by a rotating stage 143 about an axis perpendicular to the Figure 2 plane of the paper.

[0115] The mirror 63 is arranged on the optical path of the light beam that has passed through the prisms 41 to 43. The mirror 63 can be rotated by a rotating stage 163 about an axis perpendicular to the Figure 2 plane of the paper. The grating 53 is arranged on the optical path of the light beam reflected by the mirror 63.

[0116] 1.3.2 Operation

[0117] The beam emitted from the window 10a is expanded in the beam width in a plane parallel to the Figure 2 plane of the paper by each of the prisms 41 to 43. The beam passing through the prisms 41 to 43 is reflected by the mirror 63 and enters the grating 53.

[0118] The beam incident on the grating 53 is reflected by a plurality of grooves of the grating 53 and diffracted in a direction corresponding to the wavelength of the light. The grating 53 is arranged in a Littrow configuration such that the incident angle of the beam incident on the grating 53 from the mirror 63 is made to coincide with the diffraction angle of the diffracted light of the desired wavelength.

[0119] The mirror 63 and the prisms 41 to 43 narrow the beam width of the beam returning from the grating 53 in a plane parallel to the Figure 2 plane of the paper, and cause the beam to return to the inside of the laser chamber 10 through the window 10a.

[0120] The laser control processor 130 controls the rotary stages 143 and 163 via a driver (not shown). According to the rotation angles of the rotary stages 143 and 163, the incident angle of the beam incident on the grating 53 changes, and the wavelength selected by the narrowbanding module 14 changes.

[0121] The laser control processor 130 controls the rotary stage 163 based on the target short wavelength λ1 and the target long wavelength λ2 received from the exposure control processor 210, such that the attitude of the mirror 63 changes periodically for each of a plurality of pulses. Thus, the center wavelength of the pulsed laser changes periodically between the target short wavelength λ1 and the target long wavelength λ2 for each of the plurality of pulses. In this way, the laser device 100 outputs a pulsed laser including a plurality of center wavelengths.

[0122] The focal length in the exposure device 200 depends on the wavelength of the pulsed laser. The pulsed laser oscillating at a plurality of wavelengths and incident on the exposure device 200 can be imaged at a plurality of different positions in the direction of the optical axis of the pulsed laser, and thus the depth of focus can be substantially increased. For example, even when exposing a thick resist film, the imaging performance in the thickness direction of the resist film can be maintained. Alternatively, the resist profile representing the cross-sectional shape of the developed resist film can be adjusted.

[0123] 1.4 Periodic wavelength change and cumulative spectrum

[0124] Figure 3 is a graph showing a periodic wavelength change. In Figure 3 , the horizontal axis represents time t and the vertical axis represents wavelength λ. Figure 3 The small circles shown respectively represent the time t when the pulsed laser is output and the center wavelength at this time.

[0125] InFigure 3 In the example shown, the center wavelength varies periodically between the target short wavelength λ1 and the target long wavelength λ2. Let the number of pulses in one period of the wavelength variation be N, and let the repetition frequency of the pulsed laser be F. The period T of the wavelength variation is given by the following formula.

[0126] T = N / F

[0127] Figure 4 The cumulative spectrum of the pulsed laser including multiple center wavelengths is shown. Figure 4 The cumulative spectrum shown corresponds to Figure 3 the cumulative spectrum of one period of the wavelength variation shown. In Figure 4 , the horizontal axis represents the wavelength λ, and the vertical axis represents the light intensity I. The dashed lines represent the spectra of the pulsed laser for each pulse, and their respective center wavelengths coincide with the peak wavelengths. As Figure 3 shown, by changing the center wavelength in multiple steps between the target short wavelength λ1 and the target long wavelength λ2, Figure 4 the cumulative spectrum shown can become a flat-topped shape having a substantially uniform light intensity I between the target short wavelength λ1 and the target long wavelength λ2.

[0128] 1.5 Scanning Exposure

[0129] Figure 5 The photosensitive substrate exposed by the exposure apparatus 200 is shown. The photosensitive substrate is, for example, a single-crystalline silicon plate having a substantially disk-shaped shape. The photosensitive substrate is exposed for each partition such as the scanning fields SF1, SF2, etc. The scanning fields SF1, SF2 are regions where several semiconductor chips out of the multiple semiconductor chips formed on the photosensitive substrate are formed, and correspond to the regions of the mask patterns of one photomask transferred by one scan. The numbers included in the symbols SF1, SF2 represent the exposure order. When explaining without specifying the exposure order, the numbers are not marked and only SF is noted.

[0130] First, the photosensitive substrate is moved to irradiate the first scanning field SF1 with pulsed laser, and the first scanning field SF1 is exposed. Next, the photosensitive substrate is moved to irradiate the second scanning field SF2 with pulsed laser, and the second scanning field SF2 is exposed. The other scanning fields SF are also exposed in sequence, and when the last scanning field SFkmax is exposed, the exposure of this photosensitive substrate ends.

[0131] Figures 6 - 8 The situation where the position of the scanning field SF of the photosensitive substrate changes with respect to the beam cross-section B of the pulsed laser is shown. The direction of the position change of the scanning field SF is set as the Y-axis direction, and the direction perpendicular to the Y-axis direction is set as the X-axis direction.

[0132] When exposing one scanning field SF, pulsed laser is continuously output at a prescribed repetition frequency. Continuously outputting pulsed laser at a prescribed repetition frequency is called burst output. When moving the exposure position from one scanning field SF to another scanning field SF, the output of the pulsed laser is stopped. Therefore, in order to expose one photosensitive substrate, burst output is repeated multiple times.

[0133] The width of the scanning field SF in the X-axis direction is equivalent to the width of the pulsed laser beam cross-section B in the X-axis direction at the position of the worktable WT (refer to Figure 1 ). The width of the scanning field SF in the Y-axis direction is larger than the width W of the pulsed laser beam cross-section B in the Y-axis direction at the position of the worktable WT.

[0134] According to Figure 6 , Figure 7 , Figure 8 's order, the process of scanning and exposing each scanning field SF in the Y-axis direction using pulsed laser is carried out. First, as Figure 6 shows, the worktable WT is positioned such that the +Y-direction end SFy+ of the scanning field SF is located at a position that is a prescribed distance away from the -Y-direction end By- of the beam cross-section B in the -Y direction. Then, the worktable WT is accelerated in the +Y direction until it reaches a speed Vy until the position of the +Y-direction end SFy+ of the scanning field SF coincides with the position of the -Y-direction end By- of the beam cross-section B. As Figure 7 shows, while moving the worktable WT in the +Y direction so that the position of the scanning field SF moves relative to the position of the beam cross-section B at a constant linear speed Vy, the scanning field SF is exposed. As Figure 8 shows, after the worktable WT moves until the -Y-direction end SFy- of the scanning field SF passes through the +Y-direction end By+ of the beam cross-section B, the scanning of the scanning field SF ends.

[0135] In this way, exposure is carried out while moving the position of the scanning field SF relative to the beam cross-section B. When taking the scanning field SF as a reference, it is also possible to scan in the -Y direction using pulsed laser.

[0136] The time Ts required for the scanning field SF to move a distance equivalent to the width W of the pulsed laser beam cross-section B at a speed Vy is as follows.

[0137] Ts = W / Vy

[0138] The number of irradiation pulses Ns of the pulsed laser irradiated to any part in the scanning field SF is the same as the number of pulses of the pulsed laser generated within the required time Ts, as described below.

[0139] Ns = F · Ts

[0140] Preferably, the number of irradiation pulses Ns of the pulsed laser irradiated to any part in the scanning field SF is a multiple of the number of pulses N in one cycle of the wavelength change. Thus, pulsed laser with the number of irradiation pulses Ns having the same cumulative spectrum is irradiated to any part of the scanning field SF. As a result, the deviation of the exposure result based on the irradiation position is small, and high-quality electronic devices can be manufactured.

[0141] 1.6 magnification distortion

[0142] The exposure apparatus 200 transfers the pattern of the photomask onto the photosensitive substrate at a predetermined reduction ratio, for example, 1 / 4 size. However, sometimes the size of the pattern transferred onto the photosensitive substrate is larger or smaller than the expected size. This phenomenon can be regarded as the shift of each point in the plane of the photosensitive substrate relative to the position where it should originally be, and this shift varies according to the distance from the optical axis, so it is called magnification distortion.

[0143] In photolithography, depending on the design of the exposure apparatus 200 and the settings of the optical system during exposure, whether magnification or reduction caused by magnification distortion occurs will change, or the degree of magnification or reduction will change. When manufacturing electronic devices, multiple exposures are performed through different exposure apparatuses 200 or different settings, so magnification distortion becomes the cause of the superimposed error between multiple layers.

[0144] 1.7 chromatic aberration

[0145] Figure 9 is a schematic diagram of the projection optical system 202 included in the exposure apparatus 200. In Figure 9 the marginal rays of light with the target short wavelength λ1 and the target long wavelength λ2 from the photomask disposed on the mask stage MS to the photosensitive substrate disposed on the workpiece stage WT are shown. Regarding the target short wavelength λ1, the position of the photomask and the position of the photosensitive substrate are in a conjugate relationship, and the pattern of the photomask is transferred onto the photosensitive substrate.

[0146] The optical system of the exposure apparatus 200 is designed such that the aberration is minimized at a certain determined design wavelength, for example, the target short wavelength λ1. However, when using light with a wavelength different from the design wavelength, for example, the target long wavelength λ2, according to the wavelength dependence of the refraction angle, the traveling direction of the light is different from the case of using light with the design wavelength. This difference is called chromatic aberration.

[0147] Chromatic aberration has the effect of shifting the image in two directions, the direction of the optical axis AX and the direction perpendicular to the optical axis AX. The chromatic aberration component that shifts the image in the direction of the optical axis AX is called longitudinal chromatic aberration, and the chromatic aberration component that shifts the image in the direction perpendicular to the optical axis AX is called lateral chromatic aberration. In Figure 9 Δz is used to represent the longitudinal chromatic aberration, and Δx is used to represent the lateral chromatic aberration.

[0148] 1.8x chromatic aberration of magnification

[0149] Figure 10 Shows the case where the image formed on the photosensitive substrate by the Figure 9 shown projection optical system 202 is distorted. The dashed line represents the image based on the target short wavelength λ1, and the solid line represents the image based on the target long wavelength λ2. The lateral chromatic aberration Δx sometimes varies according to the distance of the object point or image point from the optical axis AX, and sometimes causes magnification distortion. The magnification distortion caused by the lateral chromatic aberration Δx is called chromatic aberration of magnification.

[0150] When exposing with light containing multiple central wavelengths, there are wavelengths different from the design wavelength, so chromatic aberration of magnification occurs.

[0151] 1.9x telecentric error

[0152] On the object side or image side of the imaging optical system, when the chief ray is parallel to the optical axis AX, it is called telecentric on the object side or image side. In modern exposure apparatuses, both the object side, i.e., the reticle side, and the image side, i.e., the photosensitive substrate side, of the projection optical system are telecentric, and this situation is called double-sided telecentric.

[0153] The double-sided telecentric optical system has advantages such as that the movement of the photosensitive substrate or reticle in the direction of the optical axis AX does not cause magnification distortion. In Figure 9 the shown projection optical system 202, the position of the reticle and the position of the photosensitive substrate are in a conjugate relationship. Figure 9 The shown projection optical system 202 is double-sided telecentric for light of wavelength λ1, but may not be double-sided telecentric for light of wavelength λ2.

[0154] Refer to Figures 11 - 19 to explain the telecentric error of magnification. Figure 11 is a schematic diagram of an optical system including a part of the illumination optical system 201 and the double-sided telecentric projection optical system 202. In Figure 11 , the position of the reticle and the position of the photosensitive substrate are in a conjugate relationship. In addition, the pupil IP of the illumination optical system 201 is located at the conjugate point CP of the pupil PP of the projection optical system 202. Figure 11 Shows the ideal state without telecentric error of magnification. In this case, even if the photosensitive substrate moves up and down in the direction of the optical axis AX, the size of the image remains unchanged.

[0155] Figure 12 Shows in Figure 11Change of the chief ray when the pupil IP of the illumination optical system 201 in the optical system shown is displaced in the direction of the optical axis AX. The pupil IP of the illumination optical system 201 is displaced from the conjugate point CP with the pupil PP of the projection optical system 202 along the optical axis AX of the pulsed laser in the direction of arrow D1. As a result, the chief ray changes from the ideal state ID to the actual state RE, and the incident angle on the photosensitive substrate becomes non-perpendicular. At this time, if the photosensitive substrate is moved in the direction of the optical axis AX, the size of the image changes. The pupil IP of the illumination optical system 201 corresponds to the first pupil in the present disclosure, the pupil PP of the projection optical system 202 corresponds to the second pupil in the present disclosure, and the position of the conjugate point CP corresponds to the reference position in the present disclosure.

[0156] Figures 13 - 15 Shows the case where the image formed on the photosensitive substrate by the Figure 12 optical system shown changes. The position Z0 in the Z direction is the best focus position of the projection optical system 202, and at the position Z0, the image formed on the photosensitive substrate before and after the displacement of the pupil IP does not change. However, at a position Z0+ shifted from the position Z0 in the Z direction, the image changes from the ideal state ID to the actual state RE and becomes smaller. On the contrary, at a position Z0- shifted from Z0 in the -Z direction, the image becomes larger.

[0157] Figure 16 Shows the case where Figure 11 the chief ray changes when the pupil IP of the illumination optical system 201 in the optical system shown is displaced in the direction opposite to Figure 12 the above. The pupil IP of the illumination optical system 201 is displaced from the conjugate point CP with the pupil PP of the projection optical system 202 along the optical axis AX of the pulsed laser in the direction of arrow D2.

[0158] Figures 17 - 19 Shows the case where the image formed on the photosensitive substrate by the Figure 16 optical system shown changes. Similar to Figure 14 the above, at the position Z0, the image formed on the photosensitive substrate before and after the displacement of the pupil IP is not deformed. However, at a position Z0+ shifted from the position Z0 in the Z direction, the image changes from the ideal state ID to the actual state RE and becomes larger. On the contrary, at a position Z0- shifted from Z0 in the -Z direction, the image becomes smaller.

[0159] As Figures 12 - 19 shown, the error caused by the magnification or reduction of the image generated when the photosensitive substrate is displaced from the best focus position is called the magnification telecentric error. Since the traveling direction of the chief ray can be controlled by the position of the pupil IP of the illumination optical system 201, the magnitude of the magnification telecentric error can be controlled.

[0160] 1.10 Problems of the Comparative Example

[0161] Figure 20 It is a schematic diagram showing a part of the marginal rays of the pulsed laser incident on the workpiece table WT when generating longitudinal chromatic aberration Δz and lateral chromatic aberration Δx. Figure 20 Equivalent to extracting Figure 9 A diagram of a part of Figure 20 It includes the marginal rays of the target short wavelength λ1 and the marginal rays of the target long wavelength λ2, and the front end of each marginal ray represents the best focusing position of each wavelength.

[0162] Figure 21 Schematically shows Figure 20 The imaging regions of the light of each wavelength of the pulsed laser shown. The image generated by the pulsed laser does not suddenly disappear even if it deviates from the best focusing position, but the contrast gradually decreases within an imaging region of a certain size and does not form an image when leaving the imaging region. The imaging region does not have a clear boundary line, but is shown as an ellipse for convenience. Due to the longitudinal chromatic aberration Δz, for example, the light of the target long wavelength λ2 is imaged at a position more offset in the -Z direction than the target short wavelength λ1. On the other hand, lateral chromatic aberration Δx is generated in opposite directions centered on the optical axis AX. For example, the light of the target long wavelength λ2 is imaged at a position more offset outward than the target short wavelength λ1 centered on the optical axis AX.

[0163] Figure 22 It is a cross-sectional view showing the resist profile when developing a photosensitive substrate exposed with the pulsed laser shown by Figure 20 and Figure 21 The photosensitive substrate includes a resist film R formed on the surface of the semiconductor substrate SUB. Figure 20 and Figure 21 The pulsed laser shown by

[0164] Figure 23 shows the offset of the image on the photosensitive substrate scanned and exposed with the pulsed laser shown by Figure 20 and Figure 21 As shown by Figure 23 For the target short wavelength λ1 and the target long wavelength λ2, the imaging positions in the X direction are different, and especially at the ends far from the optical axis AX in the X direction and -X direction, this offset becomes significant. Therefore, even for a thin resist film R, sometimes the image is offset or blurred due to the lateral chromatic aberration Δx. In addition, with reference to Figures 6 - 8In the described scanning exposure, while irradiating a pulsed laser, the photosensitive substrate is moved in the Y direction, so that the lateral chromatic aberration in the Y direction is averaged out.

[0165] In International Publication No. 2021 / 110343, it is disclosed that the pattern is offset in advance according to the position within the photomask, or a sub-resolution assist feature (SRAF) is inserted. However, such a photomask is optimized using specific spectral parameters, and even for the exposure of the same pattern, other photomasks must be designed and fabricated when the spectral parameters change. In addition, sometimes there is not enough area around the pattern to be exposed within the photomask to arrange the assist pattern. In addition, there is a lower limit in manufacturing for the size of the assist pattern, and if the size of the assist pattern is too large, sometimes the effect of the assist pattern becomes excessive.

[0166] The embodiment described below relates to the following: By generating a magnification telecentric error -δx to cancel the lateral chromatic aberration Δx in the case of exposure using multiple wavelengths, the magnification chromatic aberration is suppressed.

[0167] 2. Exposure system that offsets the position of the pupil IP of the illumination optical system 201

[0168] 2.1 Principle

[0169] Figure 24 It is a schematic diagram showing a part of the chief ray of the pulsed laser incident on the workpiece stage WT when generating a magnification telecentric error. Figure 24 Equivalent to extracting Figure 12 A part of the figure. For ease of explanation, it is assumed that no lateral chromatic aberration is generated or the lateral chromatic aberration is extremely small. In this case, the chief rays of the target short wavelength λ1 and the target long wavelength λ2 are common.

[0170] Figure 25 Schematically shows Figure 24 The imaging regions of the light of each wavelength of the pulsed laser shown. Due to the longitudinal chromatic aberration Δz, for example, the light of the target long wavelength λ2 is imaged at a position more offset in the -Z direction than the target short wavelength λ1. On the other hand, even when it is assumed that no lateral chromatic aberration is generated or the lateral chromatic aberration is extremely small, when the incident angle of the chief ray on the photosensitive substrate becomes non-vertical due to the offset of the pupil IP of the illumination optical system 201, a magnification telecentric error δx determined by the longitudinal chromatic aberration Δz and the incident angle is generated between the target short wavelength λ1 and the target long wavelength λ2.

[0171] Figure 26 Schematically shows in Figure 24 The imaging regions of the light of each wavelength of the pulsed laser shown when considering the lateral chromatic aberration Δx. Figure 26 The imaging region shown is equivalent to takingFigure 21 The lateral chromatic aberration Δx shown and Figure 25 the region obtained by adding the magnification telecentric error δx shown. In Figure 26 , the lateral chromatic aberration Δx and the magnification telecentric error δx act in the same direction, resulting in a large magnification distortion Δx + δx.

[0172] Figure 27 is a schematic diagram showing a part of the chief ray of the pulsed laser incident on the workpiece table WT when a magnification telecentric error -δx in the opposite direction to Figure 24 is generated. Figure 27 Is equivalent to extracting Figure 16 a part of the figure. For ease of explanation, assuming that no lateral chromatic aberration is generated or the lateral chromatic aberration is extremely small, the chief ray of the target short wavelength λ1 and the chief ray of the target long wavelength λ2 are common.

[0173] Figure 28 Schematically shows Figure 27 the imaging regions of the light of each wavelength of the pulsed laser shown. Due to the longitudinal chromatic aberration Δz, for example, the light of the target long wavelength λ2 is imaged at a position more offset in the -Z direction than the target short wavelength λ1. On the other hand, even assuming that no lateral chromatic aberration is generated or the lateral chromatic aberration is extremely small, when the incident angle of the chief ray on the photosensitive substrate becomes non-vertical due to the offset of the pupil IP of the illumination optical system 201, a magnification telecentric error -δx determined by the longitudinal chromatic aberration Δz and the incident angle is generated between the target short wavelength λ1 and the target long wavelength λ2. In Figure 25 and Figure 28 , since the offset directions of the pupil IP of the illumination optical system 201 are different, the magnification telecentric error δx in Figure 25 and the magnification telecentric error -δx in Figure 28 are generated in opposite directions.

[0174] Figure 29 Schematically shows the imaging regions of the light of each wavelength in the pulsed laser shown in Figure 27 when the lateral chromatic aberration Δx is considered. Figure 29 The imaging region shown is equivalent to the region obtained by adding the lateral chromatic aberration Δx shown in Figure 21 and the magnification telecentric error -δx shown in Figure 28 . As shown in Figure 29 , by making the lateral chromatic aberration Δx and the magnification telecentric error -δx act in opposite directions to cancel each other out, the offset of the imaging position caused by the lateral chromatic aberration Δx on the photosensitive substrate can be reduced using the magnification telecentric error -δx. Thus, the magnification distortion becomes smaller.

[0175] 2.2 Structure

[0176] Figure 30Schematically shows the structure of the exposure system in the first embodiment. In the first embodiment, the exposure apparatus 200 includes a measurement unit 303, and the illumination optical system 201 includes a drive mechanism 203.

[0177] The measurement unit 303 includes: a stage on which the exposed photosensitive substrate is mounted; and a sensor that observes the exposure state of the photosensitive substrate. The measurement unit 303 drives the stage under the control of the exposure control processor 210, measures the pattern formed on the photosensitive substrate by the sensor, and measures the magnification distortion based on this pattern. The measurement unit 303 corresponds to the measurement sensor in the present disclosure.

[0178] The drive mechanism 203 includes an actuator that drives at least one optical element included in the illumination optical system 201 to adjust the position of the pupil IP of the illumination optical system 201. As will be described with reference to Figure 12 and Figure 16 as described, the drive mechanism 203 is configured to be able to adjust the position of the pupil IP of the illumination optical system 201 in two directions along the optical axis AX of the pulsed laser, from the conjugate point CP with the pupil PP of the projection optical system 202 towards the arrow D1 direction approaching the pupil PP and the arrow D2 direction away from the pupil PP. The drive mechanism 203 operates under the control of the exposure control processor 210.

[0179] Figure 31 Conceptually shows a first example of the illumination optical system 201 capable of moving the position of the pupil IP. The illumination optical system 201 includes a beam shaping / uniforming optical system 204, a mechanical aperture 205, and a pupil position adjustment optical system 206a.

[0180] The beam shaping / uniforming optical system 204 is, for example, an optical system that shapes a pulsed laser having a substantially rectangular beam cross-section and a Gaussian distribution-like light intensity distribution into a desired beam cross-section and uniformizes it into a uniform light intensity distribution.

[0181] The mechanical aperture 205 is a mechanical diaphragm and is disposed near the pupil IP. The mechanical aperture 205 corresponds to the mechanical diaphragm in the present disclosure.

[0182] The pupil position adjustment optical system 206a is an optical system that irradiates the light emitted from the pupil IP onto the photomask. By moving at least one optical element included in the pupil position adjustment optical system 206a using the drive mechanism 203, the position of the pupil IP moves in the direction of the optical axis AX.

[0183] Figure 32Conceptually shows a second example of an illumination optical system 201 capable of moving the position of the pupil IP. The illumination optical system 201 includes a beam shaping / uniformizing optical system 204, a diffractive optical element 207, and a pupil position adjustment optical system 206b.

[0184] The diffractive optical element 207 is an optical element having a plurality of concavities and convexities on its surface, which branches the transmitted light into a plurality of diffracted light beams. The concavities and convexities on the surface of the diffractive optical element 207 are designed to emit the diffracted light beams in desired directions respectively. The diffracted light beams emitted from the diffractive optical element 207 are incident on the pupil position adjustment optical system 206b.

[0185] The pupil position adjustment optical system 206b condenses the diffracted light beams onto the pupil IP. By driving the mechanism 203 to move at least one of the optical elements included in the pupil position adjustment optical system 206b, the condensing position, that is, the position of the pupil IP, is moved in the direction of the optical axis AX.

[0186] Figure 33 Conceptually shows a third example of an illumination optical system 201 capable of moving the position of the pupil IP. The illumination optical system 201 includes a beam shaping / uniformizing optical system 204, a micromirror array 208, a mirror 209, and a pupil position adjustment optical system 206c.

[0187] The micromirror array 208 includes a plurality of mirrors whose respective tilts can be adjusted, and is an optical element that branches the light incident on the micromirror array 208 into a plurality of reflected light beams. The tilts of the mirrors included in the micromirror array 208 are adjusted to emit the reflected light beams in desired directions respectively. The reflected light beams emitted from the micromirror array 208 are incident on the pupil position adjustment optical system 206c via the mirror 209.

[0188] The pupil position adjustment optical system 206c condenses the reflected light beams onto the pupil IP. By driving the mechanism 203 to move at least one of the optical elements included in the pupil position adjustment optical system 206c, the condensing position, that is, the position of the pupil IP, is moved in the direction of the optical axis AX.

[0189] 2.3 Operation (Correction of Magnification Distortion)

[0190] Figure 34 Is a flowchart showing the process of correcting magnification distortion in the first embodiment. The exposure control processor 210 controls the driving mechanism 203 based on the magnification distortion measured by the measurement unit 303 as follows to reduce the shift of the imaging position caused by the lateral chromatic aberration Δx, thereby correcting the magnification distortion.

[0191] In step S101, the exposure control processor 210 controls a transfer device (not shown) to set a photomask on a mask stage MS of the exposure apparatus 200.

[0192] In S103, the exposure control processor 210 sets spectral parameters of a pulsed laser including a plurality of center wavelengths. The spectral parameters include, for example, a target short wavelength λ1 and a target long wavelength λ2. Alternatively, the spectral parameters may include a wavelength difference between the target short wavelength λ1 and the target long wavelength λ2. The spectral parameters may further include the number of pulses N in one period of wavelength variation.

[0193] In step S104, the exposure control processor 210 sets the value of a counter j for determining the position of a pupil IP of the illumination optical system 201 to an initial value 1.

[0194] In step S105, the exposure control processor 210 controls the drive mechanism 203 so that the position of the pupil IP of the illumination optical system 201 becomes the j-th value.

[0195] In step S106, the exposure control processor 210 sends various parameters and signals to the laser control processor 130 to perform laser oscillation according to the spectral parameters set in step S103. In addition, the exposure control processor 210 controls the mask stage MS and the workpiece stage WT to transfer an image of the photomask based on the pulsed laser including a plurality of center wavelengths onto a photosensitive substrate and expose the photosensitive substrate. The photosensitive substrate to be exposed here may also be a photosensitive substrate for measurement different from the photosensitive substrate used for manufacturing semiconductor devices.

[0196] In step S107, the exposure control processor 210 controls the measurement unit 303 to measure magnification distortion based on a pattern formed on the exposed photosensitive substrate.

[0197] In step S108, the exposure control processor 210 determines whether the magnification distortion is below a threshold. When the magnification distortion exceeds the threshold (S108: No), the exposure control processor 210 causes the process to proceed to S109. When the magnification distortion is below the threshold (S108: Yes), the exposure control processor 210 causes the process to proceed to S110.

[0198] In step S109, the exposure control processor 210 increments the value of the counter j to update j, and then causes the process to return to step S105. An upper limit value may be set for the value of the counter j, and if j reaches the upper limit value, the exposure control processor 210 ends the processing of this flowchart.

[0199] In step S110, the exposure control processor 210 determines the position of the pupil IP of the illumination optical system 201 as the j-th value at which the magnification distortion becomes below the threshold.

[0200] In S111, the exposure control processor 210 disposes the photosensitive substrate for manufacturing a semiconductor device on the workpiece table WT, starts exposure, and ends the processing of this flowchart.

[0201] 2.4 Function

[0202] According to the first embodiment, the exposure system includes: an illumination optical system 201 that illuminates a photomask with a pulsed laser including a target short wavelength λ1 and a target long wavelength λ2; and a projection optical system 202 that illuminates the photosensitive substrate with the pulsed laser that has passed through the photomask and projects an image of the photomask. The position of the pupil IP of the illumination optical system 201 is shifted from the conjugate point CP of the pupil PP of the projection optical system 202 in the direction of arrow D2 that uses the magnification telecentric error -δx to reduce the shift of the imaging position caused by the lateral chromatic aberration Δx on the photosensitive substrate.

[0203] Thus, by shifting the position of the pupil IP of the illumination optical system 201, it is possible to reduce the shift of the imaging position caused by the lateral chromatic aberration Δx using the magnification telecentric error -δx. Therefore, even a thick resist film can be processed with high precision. In addition, compared with the case of reducing the shift of the imaging position by the design of the photomask, the degree of freedom in the design of the photomask is high. Furthermore, when changing the wavelength difference between the target short wavelength λ1 and the target long wavelength λ2, it is not necessary to newly design the photomask according to this wavelength difference, and a common photomask can be used.

[0204] According to the first embodiment, the position of the pupil IP is shifted along the optical axis AX of the pulsed laser from the conjugate point CP of the pupil PP.

[0205] Thus, by shifting the pupil IP in the direction of the optical axis AX, it is possible to suppress the change of the optical axis AX of the pulsed laser incident on the photosensitive substrate and generate the magnification telecentric error -δx.

[0206] According to the first embodiment, the exposure system includes: a drive mechanism 203 that adjusts the position of the pupil IP; and an exposure control processor 210 that controls the drive mechanism 203 to reduce the shift of the imaging position caused by the lateral chromatic aberration Δx.

[0207] Thus, it is possible to adjust the position of the pupil IP using the drive mechanism 203. Therefore, even when spectral parameters such as the wavelength difference between the target short wavelength λ1 and the target long wavelength λ2 change, it is possible to suppress magnification distortion.

[0208] According to the first embodiment, the drive mechanism 203 is configured to be able to adjust the position of the pupil IP along the optical axis AX of the pulsed laser in two directions: the direction of arrow D1 approaching the pupil PP and the direction of arrow D2 away from the pupil PP from the conjugate point CP of the pupil PP.

[0209] Thus, in the case where the moving direction of the pupil IP for suppressing magnification distortion is the arrow D1 direction approaching the pupil PP and the arrow D2 direction away from the pupil PP, an appropriate moving direction can be selected.

[0210] According to the first embodiment, the exposure system includes a measurement unit 303 that measures a pattern formed by projection onto a photosensitive substrate, and an exposure control processor 210 controls the drive mechanism 203 based on the measurement result of the measurement unit 303.

[0211] Thus, magnification distortion can be suppressed with high precision based on the measurement result of the measurement unit 303.

[0212] According to the first embodiment, the measurement unit 303 measures the magnification distortion of a pattern formed by projection onto a photosensitive substrate, and the exposure control processor 210 controls the drive mechanism 203 based on the magnification distortion.

[0213] Thus, the position of the pupil IP can be adjusted to reduce magnification distortion.

[0214] In other respects, the first embodiment is the same as the comparative example.

[0215] 3. Exposure System for Determining the Position of the Pupil IP of the Illumination Optical System 201 Based on Spectral Parameters

[0216] 3.1 Structure

[0217] Figure 35 The structure of the exposure system in the second embodiment is schematically shown. In the second embodiment, the exposure apparatus 200 includes a non-volatile memory 213. The non-volatile memory 213 stores a correction table 213a that associates spectral parameters with the position of the pupil IP of the illumination optical system 201 (see Figure 37 ). The non-volatile memory 213 can be accessed from the exposure control processor 210.

[0218] 3.2 Operation

[0219] 3.2.1 Generation of Correction Table

[0220] Figure 36 It is a flowchart showing the process of generating the correction table 213a in the second embodiment. The exposure control processor 210 generates the correction table 213a as follows.

[0221] In step S101, the exposure control processor 210 controls a transfer device (not shown) to set a photomask on the mask stage MS of the exposure apparatus 200. This is the same as the process included in the correction of magnification distortion in the first embodiment.

[0222] In step S102a, the exposure control processor 210 sets the value of the counter i for determining the spectral parameter to the initial value 1.

[0223] In S103a, the exposure control processor 210 sets the spectral parameter to the i-th value.

[0224] The processes in steps S104 to S109 are the same as the processes included in the magnification distortion correction in the first embodiment. The exposure control processor 210 searches for the position of the pupil IP at which the magnification distortion becomes below the threshold for the given spectral parameter. When the magnification distortion becomes below the threshold (S108: Yes), the exposure control processor 210 advances the process to S112a.

[0225] In step S112a, the exposure control processor 210 stores the correspondence between the i-th spectral parameter and the j-th position of the pupil IP of the illumination optical system 201 at which the magnification distortion becomes below the threshold in the correction table 213a of the non-volatile memory 213 based on the measurement result of the magnification distortion by the measurement unit 303.

[0226] In step S113a, the exposure control processor 210 determines whether the value of the counter i has reached the maximum value imax. When the value of the counter i reaches the maximum value imax (S113a: Yes), the exposure control processor 210 ends the process of this flowchart. When the value of the counter i is less than the maximum value imax (S113a: No), the exposure control processor 210 advances the process to S114a.

[0227] In step S114a, the exposure control processor 210 updates i by incrementing the value of the counter i by 1, and then returns the process to step S103a.

[0228] Figure 37 An example of the correction table 213a stored in the non-volatile memory 213 is shown. The correction table 213a is a data table that stores the spectral parameters S1 to Simax and the positions P1 to Pimax of the pupil IP of the illumination optical system 201 at which the magnification distortion becomes below the threshold corresponding to the values 1 to imax of the counter i. The positions P1 to Pimax of the pupil IP correspond to the control parameters in the present disclosure. Different correction tables 213a may be generated for each photomask.

[0229] 3.2.2 Correction of Magnification Distortion

[0230] Figure 38 This is a flowchart showing the process of correcting the magnification distortion in the second embodiment. The exposure control processor 210 controls the drive mechanism 203 based on the spectral parameters of the pulsed laser as described below. It is assumed that the photomask has been set on the mask stage MS.

[0231] In S103, the exposure control processor 210 sets the spectral parameters of the pulsed laser. This is the same as in the first embodiment.

[0232] In step S110a, the exposure control processor 210 sets the position of the pupil IP of the illumination optical system 201 corresponding to the set spectral parameters to the value read from the correction table 213a, and controls the drive mechanism 203.

[0233] In S111, the exposure control processor 210 disposes the photosensitive substrate on the workpiece table WT, starts the exposure, and ends the processing of this flowchart.

[0234] In other aspects, the second embodiment is the same as the first embodiment.

[0235] 3.3 Function

[0236] According to the second embodiment, the exposure control processor 210 can access the correction table 213a that correlates the wavelength difference between the target short wavelength λ1 and the target long wavelength λ2 with the positions P1 to Pimax of the pupil IP, and reads the position of the pupil IP corresponding to the wavelength difference from the correction table 213a to control the drive mechanism 203.

[0237] Therefore, since the position of the pupil IP can be read from the correction table 213a based on the wavelength difference between the target short wavelength λ1 and the target long wavelength λ2, the control of the drive mechanism 203 can be performed quickly.

[0238] According to the second embodiment, the exposure control processor 210 controls the drive mechanism 203 based on the spectral parameters of the pulsed laser. For example, not limited to the case of using the correction table 213a, a function of the spectral parameters and the control parameters of the drive mechanism 203 can also be used to control the drive mechanism 203. Thus, by controlling based on the spectral parameters, the steps for controlling the drive mechanism 203 can be simplified.

[0239] According to the second embodiment, the exposure control processor 210 can access the correction table 213a that correlates the spectral parameters S1 to Simax with the positions P1 to Pimax of the pupil IP, and reads the position of the pupil IP corresponding to the spectral parameters from the correction table 213a to control the drive mechanism 203.

[0240] Thus, based on the spectral parameters S1 to Simax, the position of the pupil IP is read from the correction table 213a, so that the control of the drive mechanism 203 can be performed quickly.

[0241] According to the second embodiment, the exposure system includes a measurement unit 303 that measures a pattern formed by projection onto a photosensitive substrate. Based on the measurement results of the measurement unit 303, the exposure control processor 210 stores the correspondence between the spectral parameters S1 to Simax and the positions P1 to Pimax of the pupil IP in the correction table 213a.

[0242] Thereby, a highly reliable correction table 213a for adjusting the position of the pupil IP can be generated based on the measurement results.

[0243] According to the second embodiment, the measurement unit 303 measures the magnification distortion of a pattern formed by projection onto a photosensitive substrate. For each of the spectral parameters S1 to Simax, the exposure control processor 210 stores the correspondence between the positions P1 to Pimax of the pupil IP for which the magnification distortion is below the threshold in the correction table 213a.

[0244] Accordingly, a highly reliable correction table 213a for reducing magnification distortion can be generated based on the measurement results of the magnification distortion.

[0245] 4. An exposure system including a measurement unit 303b separate from the exposure apparatus 200

[0246] 4.1 Structure

[0247] Figure 39 Schematically shows the structure of the exposure system in the third embodiment. In the third embodiment, the exposure system includes a developing apparatus 300 different from the exposure apparatus 200. The developing apparatus 300 includes a wafer transfer unit 301, a processing unit 302, a measurement unit 303b, and a developing control processor 310.

[0248] The wafer transfer unit 301 is a device that performs the transfer of the photosensitive substrate to and from the exposure apparatus 200 and the movement of the photosensitive substrate inside the developing apparatus 300.

[0249] The processing unit 302 is a device that performs operations such as coating a resist film on the photosensitive substrate, post-exposure bake (PEB) of the photosensitive substrate exposed inside the exposure apparatus 200, supply of developer, cleaning, drying, and post-development bake (PDB).

[0250] The measurement unit 303b is a device that measures the pattern formed on the photosensitive substrate through exposure and development. The measurement unit 303b can be a cross-sectional inspection SEM that measures the resist profile, a pattern position measurement device that measures the overlay error, or a device that measures the magnification distortion based on the planar shape of the resist film. The measurement unit 303b corresponds to the measurement sensor in the present disclosure. The measurement unit 303b can be provided separately from the developing apparatus 300.

[0251] The development control processor 310 is a processing device including a memory 312 storing a control program and a CPU 311 executing the control program. The development control processor 310 is specifically configured or programmed to execute various processes included in the present disclosure.

[0252] The exposure apparatus 200 may not include the measurement unit 303 described in the first embodiment.

[0253] 4.2 Operation (Correction of Magnification Distortion)

[0254] Figure 40 is a flowchart showing the process of correcting magnification distortion in the third embodiment. As described below, the development control processor 310 performs development and measurement of the photosensitive substrate, and the exposure control processor 210 controls the drive mechanism 203 based on the measurement results to reduce the shift of the imaging position caused by lateral chromatic aberration Δx, thereby performing correction of magnification distortion.

[0255] The processes of S101 to S105 are the same as those in the first embodiment. In step S106b, not only does the exposure control processor 210 control the exposure apparatus 200 to expose the photosensitive substrate, but also the development control processor 310 controls the developing apparatus 300 to develop the exposed photosensitive substrate through the developing apparatus 300.

[0256] In step S107b, the development control processor 310 controls the measurement unit 303b to measure the resist profile, overlay error, or magnification distortion of the photosensitive substrate after exposure and development. For example, the more asymmetric the inclination angle of the wall surface of the resist film is, the larger the value measured for the resist profile.

[0257] In step S108b, the exposure control processor 210 receives from the development control processor 310 the measurement results of the resist profile, overlay error, or magnification distortion measured by the measurement unit 303b, and determines whether the measurement results are below a threshold value. When the measurement results exceed the threshold value (S108b: No), the exposure control processor 210 causes the process to proceed to S109. When the measurement results are below the threshold value (S108b: Yes), the exposure control processor 210 causes the process to proceed to S110. The processes of S109, S110, and S111 are the same as those in the first embodiment.

[0258] In other aspects, the third embodiment is the same as the first embodiment. Alternatively, similar to the second embodiment, in the structure where the exposure apparatus 200 includes a non-volatile memory 213, the exposure system may include a measurement unit 303b separate from the exposure apparatus 200.

[0259] 4.3 Function

[0260] According to the third embodiment, the exposure system includes a measurement unit 303b that measures a pattern formed by projection onto a photosensitive substrate and development, and an exposure control processor 210 controls a drive mechanism 203 based on the measurement result of the measurement unit 303b.

[0261] Thereby, by measuring the developed pattern and controlling the drive mechanism 203 based on the measurement result, the product quality can be further improved.

[0262] According to the third embodiment, the measurement unit 303b measures the resist profile of the photosensitive substrate, and the exposure control processor 210 controls the drive mechanism 203 based on the asymmetry of the resist profile.

[0263] Thereby, the drive mechanism 203 is controlled based on the asymmetry of the resist profile of the developed photosensitive substrate, so that products can be manufactured with reduced asymmetry of the resist profile.

[0264] According to the third embodiment, the measurement unit 303b measures the overlay error between multiple layers formed by multiple projections and developments, and the exposure control processor 210 controls the drive mechanism 203 based on the overlay error.

[0265] Thereby, the drive mechanism 203 is controlled based on the overlay error of the developed photosensitive substrate, so that products with small overlay errors can be manufactured.

[0266] According to the third embodiment, the measurement unit 303b measures the magnification distortion according to the planar shape of the resist film included in the photosensitive substrate, and the exposure control processor 210 controls the drive mechanism 203 based on the magnification distortion.

[0267] Thereby, the drive mechanism 203 is controlled based on the magnification distortion measured according to the planar shape of the resist film of the developed photosensitive substrate, so that products with small magnification distortion can be manufactured.

[0268] 5. Others

[0269] The above description is illustrative rather than restrictive. Therefore, it is obvious to those skilled in the art that the embodiments of the present disclosure can be modified without departing from the claims. In addition, it is obvious to those skilled in the art that the embodiments of the present disclosure can be combined and used.

[0270] Unless otherwise expressly stated, the terms used throughout this specification and the claims shall be construed as "non-limiting" terms. For example, the term "comprising" or "including" shall be construed as "not limited to the content described as being included". The term "having" shall be construed as "not limited to the parts described as being had". In addition, the indefinite article "a" shall be construed as meaning "at least one" or "one or more". Further, the term "at least one of A, B, and C" shall be construed as "A", "B", "C", "A + B", "A + C", "B + C", or "A + B + C". Moreover, it shall be construed as also including combinations thereof with elements other than "A", "B", and "C".

Claims

1. An exposure system, wherein, the exposure system includes: an illumination optical system that illuminates a photomask with pulsed laser light including a plurality of center wavelengths; and a projection optical system that illuminates a photosensitive substrate with the pulsed laser light that has passed through the photomask and projects an image of the photomask, the position of a first pupil that is the pupil of the illumination optical system is shifted from a reference position that is conjugate to a second pupil that is the pupil of the projection optical system in a direction that reduces the shift of the imaging position caused by lateral chromatic aberration on the photosensitive substrate using magnification telecentric error.

2. The exposure system according to claim 1, wherein, the position of the first pupil is shifted from the reference position along the optical axis of the pulsed laser light.

3. The exposure system according to claim 1, wherein, the exposure system further includes: a drive mechanism that adjusts the position of the first pupil; and a processor that controls the drive mechanism to reduce the shift.

4. The exposure system according to claim 3, wherein, the drive mechanism is configured to be able to adjust the position of the first pupil along the optical axis of the pulsed laser light in two directions, from the reference position, toward the second pupil and away from the second pupil.

5. The exposure system according to claim 3, wherein, the illumination optical system includes: a mechanical diaphragm disposed near the first pupil; and a pupil position adjustment optical system driven by the drive mechanism.

6. The exposure system according to claim 3, wherein, the illumination optical system includes: a diffractive optical element; and a pupil position adjustment optical system that condenses the pulsed laser light that has passed through the diffractive optical element.

7. The exposure system according to claim 3, wherein, the illumination optical system includes: a micromirror array; and a pupil position adjustment optical system that condenses the pulsed laser light reflected by the micromirror array.

8. The exposure system according to claim 3, wherein, the exposure system further includes a measurement sensor that measures a pattern formed by projection onto the photosensitive substrate, the processor controls the drive mechanism based on the measurement result of the measurement sensor.

9. The exposure system according to claim 8, wherein, the measurement sensor measures the magnification distortion of the pattern formed by projection onto the photosensitive substrate, the processor controls the drive mechanism according to the magnification distortion.

10. The exposure system according to claim 3, wherein, the plurality of center wavelengths include a first wavelength and a second wavelength, the processor can access a data table that correlates the wavelength difference between the first wavelength and the second wavelength with the control parameters of the drive mechanism, and reads out the control parameters corresponding to the wavelength difference from the data table to control the drive mechanism.

11. The exposure system according to claim 3, wherein, the processor controls the drive mechanism according to the spectral parameters of the pulsed laser light.

12. The exposure system according to claim 11, wherein, The processor can access a data table that correlates the spectral parameters with the control parameters of the drive mechanism, and reads out the control parameters corresponding to the spectral parameters from the data table to control the drive mechanism.

13. The exposure system according to claim 12, wherein, the exposure system further includes a measurement sensor that measures a pattern formed by projection onto the photosensitive substrate, and the processor stores the correspondence between the spectral parameters and the control parameters in the data table based on the measurement result of the measurement sensor.

14. The exposure system according to claim 13, wherein, the measurement sensor measures the magnification distortion of the pattern formed by projection onto the photosensitive substrate, and the processor stores, for each value among multiple values of the spectral parameters, the correspondence between the control parameters for which the magnification distortion is below a threshold in the data table.

15. The exposure system according to claim 13, wherein, the measurement sensor measures the pattern formed by projection onto the photosensitive substrate and development.

16. The exposure system according to claim 3, wherein, the exposure system further includes a measurement sensor that measures a pattern formed by projection onto the photosensitive substrate and development, and the processor controls the drive mechanism based on the measurement result of the measurement sensor.

17. The exposure system according to claim 16, wherein, the measurement sensor measures the resist profile of the photosensitive substrate, and the processor controls the drive mechanism based on the asymmetry of the resist profile.

18. The exposure system according to claim 16, wherein, the measurement sensor measures the overlay error between multiple layers formed by multiple projections and developments, and the processor controls the drive mechanism based on the overlay error.

19. The exposure system according to claim 16, wherein, the measurement sensor measures the magnification distortion according to the planar shape of the resist film contained in the photosensitive substrate, and the processor controls the drive mechanism according to the magnification distortion.

20. A method for manufacturing an electronic device, wherein, the method for manufacturing the electronic device includes the following steps: using an exposure system to expose a pulsed laser on a photosensitive substrate to manufacture the electronic device, the exposure system includes: an illumination optical system that illuminates a pulsed laser including multiple central wavelengths onto a photomask; and a projection optical system that illuminates the pulsed laser that has passed through the photomask onto the photosensitive substrate and projects an image of the photomask, the position of a first pupil that is the pupil of the illumination optical system is shifted from a reference position that is conjugate to a second pupil that is the pupil of the projection optical system in a direction that uses magnification telecentric error to reduce the shift of the imaging position caused by lateral chromatic aberration on the photosensitive substrate.

Images