Exposure system, method for generating laser control parameters, and method for manufacturing electronic devices

Abstract

An exposure system which exposes a semiconductor substrate by irradiating a reticle with pulsed laser light and scanning the semiconductor substrate has a laser device which outputs pulsed laser light, an illumination optical system which guides the pulsed laser light to the reticle, a reticle stage, and a processor which controls the output of the pulsed laser light from the laser device and the movement of the reticle stage with respect to the reticle. The reticle includes regions in which a plurality of patterns are mixed and arranged in a scanning width direction orthogonal to a scanning direction of the scanning exposure, and the processor instructs the laser device of a target wavelength to output pulsed laser light of a wavelength which minimizes the variance of the optimal focus positions corresponding to the plurality of patterns, respectively.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an exposure system, a method of generating laser control parameters, and a method of manufacturing electronic devices. BACKGROUND

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

[0003] The spectral line width of the natural oscillation light of the KrF excimer laser device and the ArF excimer laser device is wide, about 350 to 400 pm. Therefore, when a projection lens is configured using a material which transmits ultraviolet rays such as KrF and ArF laser light, chromatic aberration sometimes occurs. As a result, the resolution can be reduced. Therefore, it is necessary to narrow the spectral line width of the laser light output from the gas laser device to the extent that 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 narrow module (LNM) including a narrow band element (etalon, grating, etc.) is sometimes provided. Hereinafter, the gas laser device whose spectral line width is narrowed is referred to as a narrow band gas laser device.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: U.S. Patent Application Publication No. 2015 / 0070673

[0007] Patent Literature 2: U.S. Patent Application Publication No. 2011 / 0205512

[0008] Patent Literature 3: U.S. Patent Application Publication No. 2006 / 0035160

[0009] Patent Literature 4: U.S. Patent Application Publication No. 2003 / 0227607

[0010] Patent Literature 5: U.S. Patent Application Publication No. 2018 / 0196347

[0011] Patent Literature 6: U.S. Patent Application Publication No. 2019 / 0245321

[0012] Patent Literature 7: U.S. Patent Application Publication No. 2004 / 0012844 SUMMARY

[0013] An exposure system of one aspect of the present disclosure irradiates a reticle with pulsed laser light and performs scan exposure on a semiconductor substrate, wherein the exposure system has: a laser device that outputs pulsed laser light; an illumination optical system that guides the pulsed laser light to the reticle; a reticle stage that moves the reticle; and a processor that controls the output of the pulsed laser light from the laser device and the movement of the reticle stage on the reticle, the reticle including a region in which a plurality of patterns are mixed and arranged in a scan width direction orthogonal to a scan direction of the scan exposure, the processor instructing the laser device of a target wavelength of the pulsed laser light to output pulsed laser light of a wavelength that minimizes a variance of optimal focus positions corresponding to the plurality of patterns, respectively.

[0014] A laser control parameter generation method of another aspect of the present disclosure is executed by a processor, wherein the laser control parameter includes a wavelength of pulsed laser light irradiated to a reticle, the laser control parameter generation method includes the steps of: the processor calculating optimal focus positions corresponding to a plurality of patterns included in the reticle, respectively; the processor calculating, for a combination of the plurality of patterns, a wavelength of pulsed laser light that minimizes a variance of the optimal focus positions corresponding to the plurality of patterns included in the combination, respectively; and the processor associating the combination of the plurality of patterns and the wavelength of the pulsed laser light that minimizes the variance and saving in a file.

[0015] A method of manufacturing an electronic device of another aspect of the present disclosure includes the step of: using an exposure system to irradiate a reticle with pulsed laser light and perform scan exposure on a photosensitive substrate to manufacture an electronic device, the exposure system having: a laser device that outputs pulsed laser light; a reticle; an illumination optical system that guides the pulsed laser light to the reticle; a reticle stage that moves the reticle; and a processor that controls the output of the pulsed laser light from the laser device and the movement of the reticle stage on the reticle, the reticle including a region in which a plurality of patterns are mixed and arranged in a scan width direction orthogonal to a scan direction of the scan exposure, the processor instructing the laser device of a target wavelength of the pulsed laser light to output pulsed laser light of a wavelength that minimizes a variance of optimal focus positions corresponding to the plurality of patterns, respectively. BRIEF DESCRIPTION OF DRAWINGS

[0016] Hereinafter, several embodiments of the present disclosure will be described as simple examples with reference to the accompanying drawings.

[0017] Figure 1 A graph showing an example of the difference in optimal focus between patterns.

[0018] Figure 2 The structure of the exposure system of the comparative example is schematically shown.

[0019] Figure 3 An example of the output mode of the light emission trigger signal transmitted from the exposure control section to the laser control section is shown.

[0020] Figure 4 An example of an exposure pattern showing a step-and-scan exposure on a wafer.

[0021] Figure 5 An example showing a relationship between one scan field and a static exposure area on a wafer.

[0022] Figure 6 An explanatory view of a static exposure area.

[0023] Figure 7 An example of a structure of a lithography system according to Embodiment 1.

[0024] Figure 8 An example of a structure of a laser device.

[0025] Figure 9 A plan view schematically showing an example of a mask pattern.

[0026] Figure 10 Figures showing focus curves of each pattern (1) to (3) of Case 1 shown in the upper paragraph of Figure 9

[0027] Figures showing focus curves of each pattern (1) and (2) of Case 2 shown in the lower paragraph of Figure 11 Figure 9 An example showing a relationship between a mask pattern, an optimum wavelength, and a target wavelength.

[0028] Figure 12 A flowchart showing an example of a process performed by the lithography control section of Embodiment 1.

[0029] Figure 13 A flowchart showing an example of a process performed by the lithography control section of Embodiment 1.

[0030] Figure 14 A flowchart showing an example of the contents of the process of Step S13 applied to

[0031] Figure 15 Figure 13 A flowchart showing an example of the contents of the process of Step S13 applied to

[0032] Figure 16 A plan view schematically showing a part of a pattern of a mask.

[0033] Figure 17 A cross-sectional view taking the line 17-17 of Figure 16 as a cutting line.

[0034] Figure 18 A chart showing an example of data saved in a file A.

[0035] Figure 19 ​​is a graph showing an example of data saved in file B.

[0036] Figure 20 is a flowchart showing an example of the process performed by the exposure control section of Embodiment 1.

[0037] Figure 21 is a flowchart showing an example of the process performed by the laser control section of Embodiment 1.

[0038] Figure 22 shows an example of the relationship between the mask pattern in the lithography system of Embodiment 2 and the wavelengths of the optimum wavelength, the target wavelength, and the cumulative spectrum.

[0039] Figure 23 is a flowchart showing an example of the process performed by the exposure control section of Embodiment 2.

[0040] Figure 24 shows an example of the structure of the lithography system of Embodiment 3.

[0041] Figure 25 is a flowchart showing an example of the process in the lithography control section of Embodiment 3.

[0042] Figure 26 shows another example of the structure of the laser device.

[0043] Figure 27 shows an example of the structure of the semiconductor laser system.

[0044] Figure 28 is a conceptual diagram of the spectral line width achieved by chirping.

[0045] Figure 29 is a schematic diagram showing the relationship between the current flowing in the semiconductor laser, the wavelength variation based on chirping, the spectral waveform, and the light intensity.

[0046] Figure 30 is a graph for explaining the rise time of a semiconductor optical amplifier.

[0047] Figure 31 shows an example of the structure of an exposure device. DETAILED DESCRIPTION

[0048] - TABLE OF CONTENTS -

[0049] 1. Explanation of Terms

[0050] 2. Overview of the Exposure System of the Comparative Example

[0051] 2.1 Structure

[0052] 2.2 Operation

[0053] 2.3 Example of exposure operation on wafer

[0054] 2.4 Relationship between scan field and static exposure area

[0055] 2.5 Problem

[0056] 3. Embodiment 1

[0057] 3.1 Outline of photolithography system

[0058] 3.1.1 Configuration

[0059] 3.1.2 Operation

[0060] 3.2 Example of laser device

[0061] 3.2.1 Configuration

[0062] 3.2.2 Operation

[0063] 3.2.3 Others

[0064] 3.3 Example of focus curve of mask pattern

[0065] 3.4 Example of processing content of photolithography control section

[0066] 3.5 Example of processing content of exposure control section

[0067] 3.6 Example of processing content of laser control section

[0068] 3.7 Effects / advantages

[0069] 3.8 Others

[0070] 4. Embodiment 2

[0071] 4.1 Configuration

[0072] 4.2 Operation

[0073] 4.3 Effects / advantages

[0074] 5. Embodiment 3

[0075] 5.1 Configuration

[0076] 5.2 Operation

[0077] 5.3 Effects / advantages

[0078] 5.4 Others

[0079] 6. Variance on optimum focus position of each pattern

[0080] 7. Example of excimer laser device using solid-state laser device as oscillator

[0081] 7.1 Structure

[0082] 7.2 Operation

[0083] 7.3 Explanation of semiconductor laser system

[0084] 7.3.1 Structure

[0085] 7.3.2 Operation

[0086] 7.3.3 Others

[0087] 7.4 Effects

[0088] 7.5 Others

[0089] 8. Hardware configuration of various control units

[0090] 9. Method of manufacturing electronic device

[0091] 10. Others

[0092] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show several examples of the present disclosure, and do not limit the present disclosure. Furthermore, the structures and operations explained in each of the embodiments are not necessarily essential to the present disclosure. In addition, the same reference numerals are given to the same structural elements throughout the description of each of the embodiments for which the explanations are omitted.

[0093] 1. Explanation of terms

[0094] The terms used in the present disclosure are defined as follows.

[0095] Critical Dimension (CD) refers to the size of a fine pattern formed on a wafer of a semiconductor or the like.

[0096] Superposition refers to the superposition of a fine pattern formed on a wafer of a semiconductor or the like.

[0097] Spectral line width Δλ is an index value of the spectral line width that affects exposure performance. The spectral line width Δλ may, for example, also be the bandwidth in which the integrated energy of a laser spectrum becomes 95%.

[0098] CD Uniformity (CDU) refers to the uniformity of the line width CD of a pattern formed on a wafer. Methods of evaluating CDU are various, and evaluation is performed in a statistical manner using σ (standard deviation) within a lot, within a wafer, or within a scanning field. When the value of σ is large (i.e., the deviation is large), the operation of the device also deviates, and thus various countermeasures are taken to make the value of σ as small as possible.

[0099] The mask 3D effect refers to the deviation between the calculated amplitude and phase of diffracted light based on Kirchhoff's assumptions about thin-walled structures and the amplitude and phase of diffracted light generated from a mask pattern of an actual mask with a three-dimensional structure. This deviation also depends on the type of mask; however, mask patterns (e.g., the line portion of a line / spaced pattern) are three-dimensional structures with a thickness of approximately 100 nm. Due to this thickness, the amplitude and phase of the diffracted light generated from the mask pattern deviate from those calculated based on Kirchhoff's assumptions in the theory of light diffraction (ignoring the step difference of the diffraction plane). To correctly evaluate the amplitude and phase deviation based on this mask 3D effect, electromagnetic field analysis is required. The mask 3D effect is a previously existing phenomenon, but it becomes significant with the miniaturization of patterns, and its impact on photolithography cannot be ignored. Mask and mask plate, mask pattern and mask plate pattern are synonymous.

[0100] The optimal focus difference between patterns refers to the phenomenon that when multiple patterns exist on the same mask, the optimal focus position of each pattern is different. The main causes of this optimal focus difference are wavefront aberration of the projection optics system of the exposure apparatus, the three-dimensional effect of the mask, and the film thickness effect of the resist. Regarding each pattern, near its optimal focus point, the focus deviation (CD) is least affected by focus shift. Therefore, when the difference between optimal focuses is small, it is less affected by focusing when viewed as a whole, and the focus deviation (CDU) is also good.

[0101] Figure 1 This is a graph showing examples of optimal focus difference between patterns. The horizontal axis represents the focus position, and the vertical axis represents the CD value. Figure 1 This characteristic curve representing the relationship between focus and CD is called the focus curve. Here, the focus curves FC(1), FC(2), and FC(3) for patterns (1), (2), and (3) are shown respectively. Figure 1 BF(1), BF(2) and BF(3) in the figure represent the best focus positions of pattern (1), pattern (2) and pattern (3) respectively.

[0102] Ideally, the optimal focus points for all patterns should be concentrated in one place (e.g., Figure 1 (At the dashed line). By adjusting the center wavelength of the laser, optimal focus control of the pattern can be achieved. Changing the center wavelength generates the 0θ series aberration in Zernike wavefront aberration. The 0θ series aberration imparts different phase errors to diffracted light passing through different NA (numerical aperture), thus causing different focus offsets for different patterns.

[0103] 2. Overview of the comparative exposure system

[0104] 2.1 Structure

[0105] Figure 2 The structure of the exposure system of the comparative example is schematically shown. The comparative example of the present disclosure is a manner known only to the applicant, not a publicly known example admitted by the applicant himself or herself. The exposure system 10 includes a laser device 12 and an exposure device 14. The laser device 12 is a wavelength-variable narrowband oscillation ArF laser device including a laser control section 20, a laser cavity not shown, and a narrowband module.

[0106] The exposure device 14 includes an exposure control section 40, a beam delivery unit (BDU) 42, a high reflection mirror 43, an illumination optical system 44, a reticle 46, a reticle stage 48, a projection optical system 50, a wafer holder 52, a wafer stage 54, and a focus sensor 58.

[0107] The wafer holder 52 holds a wafer WF. The illumination optical system 44 is an optical system that guides the pulsed laser to the reticle 46. The illumination optical system 44 shapes the laser beam into a scan beam in which a substantially rectangular light intensity distribution is homogenized. Further, the illumination optical system 44 controls the incident angle of the laser beam with respect to the reticle 46. The projection optical system 50 images the reticle pattern on the wafer WF. The focus sensor 58 measures the height of the wafer surface.

[0108] The exposure control section 40 is connected to the reticle stage 48, the wafer stage 54, and the focus sensor 58. Further, the exposure control section 40 is connected to the laser control section 20. The exposure control section 40 and the laser control section 20 are each configured using a processor not shown, including a storage device such as a memory. The storage device can also be mounted on the processor.

[0109] 2.2 Action

[0110] The exposure control section 40 controls the movement of the wafer stage 54 in the Z-axis direction in accordance with the height of the wafer WF measured by the focus sensor 58, to correct the focus position in the wafer height direction (Z-axis direction).

[0111] The exposure control section 40 sends the control parameters of the target laser to the laser control section 20 in a step-and-scan manner, controls the reticle stage 48 and the wafer stage 54 while sending a light emission trigger signal Tr, and scans the image of the exposure reticle 46 on the wafer WF. The control parameters of the target laser include, for example, a target wavelength λt and a target pulse energy Et. In addition, the description of "target laser" means "target pulsed laser". The "pulsed laser" is sometimes simply described as "laser".

[0112] The laser control section 20 controls the selection wavelength of the narrowband module so that the wavelength λ of the pulsed laser light output from the laser device 12 becomes the target wavelength λt, and controls the excitation intensity so that the pulse energy E becomes the target pulse energy Et, and outputs the pulsed laser light in accordance with the light emission trigger signal Tr. Further, the laser control section 20 transmits various measurement data of the pulsed laser light output in accordance with the light emission trigger signal Tr to the exposure control section 40. Among the various measurement data, for example, the wavelength λ and the pulse energy E are included.

[0113] 2.3 Example of exposure operation on a wafer

[0114] Figure 3 An example of the output mode of the light emission trigger signal Tr transmitted from the exposure control section 40 to the laser control section 20 is shown. In Figure 3 In the example shown, after adjustment oscillation is performed for each wafer WF, the actual exposure mode is entered. That is, the laser device 12 initially performs adjustment oscillation, and after a prescribed time interval elapses, burst operation for the first wafer exposure (wafer #1) is performed.

[0115] The adjustment oscillation refers to oscillation in which pulsed laser light for adjustment is output although the pulsed laser light is not irradiated to the wafer WF. With respect to the adjustment oscillation, oscillation is performed under prescribed conditions until the laser is stabilized in a state in which exposure is possible, and the adjustment oscillation is performed before the batch of wafer production. The pulsed laser light is output at a prescribed frequency of several hundred Hz to several kHz, for example. During wafer exposure, generally, burst operation in which a burst period and an oscillation rest period are repeated is performed. In the adjustment oscillation, too, burst operation is performed.

[0116] In Figure 3 , the interval in which pulses are concentrated is a burst period in which pulsed laser light is continuously output for a prescribed period. Further, in Figure 3 , the interval in which there are no pulses is an oscillation rest period. In addition, in the adjustment oscillation, the length of each continuous output period of the pulses does not need to be constant, and in order to perform adjustment, the length of each continuous output period can be made different to perform continuous output operation. After the adjustment oscillation is performed, a relatively large time interval elapses, and the first wafer exposure (wafer #1) is performed in the exposure device 14.

[0117] The laser device 12 oscillates in the rest during stepping in the exposure in the step-and-scan method, and outputs pulsed laser light in accordance with the interval of the light emission trigger signal Tr during scanning. This mode of laser oscillation is referred to as a burst oscillation mode.

[0118] Figure 4 An example of the exposure mode of the step-and-scan exposure on the wafer WF is shown. Figure 4The plurality of rectangular regions shown in the wafer WF are each a scan field SF. The scan field SF is an exposure region of the 1st scan exposure, also referred to as a scan region. As shown in Figure 4 The wafer WF is divided into a plurality of exposure regions (scan fields) of a prescribed size, and each exposure region is subjected to scan exposure in a period between the start (wafer start) and the end (wafer end) of wafer exposure, whereby wafer exposure is performed.

[0119] That is, in wafer exposure, the following steps are repeated: a 1st prescribed exposure region of the wafer WF is exposed by 1st scan exposure (scan #1), and then a 2nd prescribed exposure region is exposed by 2nd scan exposure (scan #2). In 1st scan exposure, a plurality of pulsed laser light (pulse #1, pulse #2,...) can be continuously output from the laser device 12. After the scan exposure (scan #1) of the 1st prescribed exposure region ends, the scan exposure (scan #2) of the 2nd prescribed exposure region is performed with a prescribed time interval. This scan exposure is sequentially repeated, and after the scan exposure of all the exposure regions of the 1st wafer WF ends, the adjustment oscillation is performed again, and then wafer exposure (wafer #2) of the 2nd wafer WF is performed.

[0120] The step-and-scan exposure is performed in the order of the dashed arrows shown in Figure 4 until the wafer start → scan #1 → scan #2 →... → scan #126 → wafer end. The wafer WF is an example of the "semiconductor substrate" and the "photosensitive substrate" in the present disclosure.

[0121] 2.4 Relationship between scan field and static exposure region

[0122] Figure 5 The relationship between 1 scan field SF on the wafer WF and a static exposure region SEA is shown. The static exposure region SEA is a substantially rectangular beam irradiation region in which the light intensity distribution is substantially uniform, which is used in scan exposure of the scan field SF. The substantially rectangular, substantially uniform scan beam shaped by the illumination optical system 44 is irradiated onto the reticle 46, and the reticle 46 and the wafer WF are moved in the Y-axis direction at different orientations from each other in the Y-axis direction according to the reduction magnification of the projection optical system 50 while the exposure is performed. Thus, in each scan field on the wafer WF, the reticle pattern is scan-exposed. The static exposure region SEA can also be understood as a region in which uniform exposure is possible based on the scan beam.

[0123] In Figure 5 , the direction toward the negative side of the Y-axis direction in the longitudinal direction is the scan direction, and the direction toward the positive side of the Y-axis direction is the wafer movement direction. The direction in which the wafer WF is moved in the Y-axis direction is the wafer movement direction. Figure 5A direction (X-axis direction) in which the paper surface is parallel to and orthogonal to the Y-axis direction is referred to as a scanning width direction. The size of the scanning field SF on the wafer WF is, for example, 33 mm in the Y-axis direction and 26 mm in the X-axis direction.

[0124] Figure 6 is an explanatory view of the static exposure area SEA. When the length in the X-axis direction of the static exposure area SEA is Bx and the width in the Y-axis direction is By, Bx corresponds to the size of the scanning field SF in the X-axis direction, and By is much smaller than the size of the scanning field SF in the Y-axis direction. The width By in the Y-axis direction of the static exposure area SEA is referred to as an N gap. The number N of pulses of the resist exposed on the wafer WF SL becomes the following expression.

[0125] N SL = (By / Vy) · f

[0126] Vy: scanning speed in the Y-axis direction of the wafer

[0127] f: repetition frequency of the laser (Hz)

[0128] 2.5 Problem

[0129] As explained in Figure 1 , in a case where there is a difference in the best focus between patterns due to aberration, mask three-dimensional effects, for example, when exposure is performed near the best focus position of the pattern (1), the inclination of the focus curve FC(1) of the pattern (1) is gentle, and thus, the focus position is not easily affected, but the inclination of the focus curve FC(3) of the pattern (3) is steep, and when the focus position fluctuates, the CD also greatly fluctuates. Thus, the overall CDU cannot be said to be good. Furthermore, the CD of the pattern (3) itself can also deviate from the target value.

[0130] 3. Embodiment 1

[0131] 3.1 Outline of the lithography system

[0132] 3.1.1 Configuration

[0133] Figure 7 A configuration example of the lithography system 100 of Embodiment 1 is shown. Regarding the configuration shown in Figure 7 , a difference from Figure 2 will be explained. Figure 7 The lithography system 100 shown in Figure 2 is configured by adding a lithography control section 110 to the configuration shown in

[0134] The lithography system 100 includes a laser device 12, an exposure device 14, and a lithography control section 110. The lithography control section 110 is configured using a processor not shown. The lithography control section 110 includes a storage device such as a memory. The processor can also include a storage device. The lithography control section 110 includes a calculation program that, while distributing the settings of the exposure device 14 and the control parameters of the laser (e.g., wavelength) in accordance with a pure (Fourier) imaging optical theory, uses a mathematical method such as linear or nonlinear optimization to find the optimal settings of the exposure device 14. This calculation program is embedded in a lithography simulation program that includes an electromagnetic field analysis function of a reticle pattern. The parameters related to the settings of the exposure device 14 here include, for example, the NA of the lens of the projection optical system 50, the illumination σ and the annular band ratio of the illumination optical system 44, and the like.

[0135] 3.1.2 Action

[0136] The lithography control section 110 finds, by the calculation program of the lithography simulation program that includes the electromagnetic field analysis function of the reticle pattern, the optimal wavelength λb for which the optimal focus position is closest (i.e., the variance is smallest) for each pattern (k) of a plurality of patterns (k) in which the reticle pattern is combined, and saves the data of the optimal wavelength λb in a file B of the lithography control section 110. In addition, "k" in the notation of the pattern (k) is an index number that identifies the kind of pattern, and in the example of Figure 1 , k is an integer of 1 to 3.

[0137] The exposure control section 40 reads the data of the optimal wavelength λb corresponding to the scanning beam SB and the position of each pattern described later from the file B, and calculates the target wavelength λt of each pulse of each scanning field SF from the data of the file B. The exposure control section 40 transmits the control parameter values (target wavelength λt, target spectral width Δλt, and target pulse energy Et) of the laser of each pulse to the laser device 12.

[0138] The subsequent exposure action can be the same as that of the exposure system 10 of Figure 2 , and can further be added, for example, the delay time Δt of the synchronization timing of the oscillator and the amplifier of the laser device 12 described later is controlled for each pulse, thereby making the spectral width Δλ of each pulse variable.

[0139] 3.2 Example of Laser Device

[0140] 3.2.1 Configuration

[0141] Figure 8 A configuration example of the laser device 12 is shown. Figure 8The illustrated laser device 12 is a narrowband ArF laser device, which includes a laser control section 20, an oscillator 22, an amplifier 24, a monitor module 26, and a shutter 28. The oscillator 22 includes a cavity 60, an output coupling mirror 62, a pulse power module (PPM) 64, a charger 66, and a narrowband module (LNM) 68.

[0142] The cavity 60 includes windows 71, 72, a pair of electrodes 73, 74, and an electrically insulating member 75. The PPM 64 includes a switch 65 and a charging capacitor not shown, which is connected to the electrode 74 via a feed path of the electrically insulating member 75. The electrode 73 is connected to the cavity 60, which is grounded. The charger 66 charges the charging capacitor of the PPM 64 in accordance with an instruction from the laser control section 20.

[0143] The narrowband module 68 and the output coupling mirror 62 constitute an optical resonator. The cavity 60 is arranged in such a manner that a discharge region in which the pair of electrodes 73, 74 is arranged is disposed in an optical path of the resonator. The output coupling mirror 62 is coated with a multilayer film that reflects a part of laser light generated in the cavity 60 and transmits another part.

[0144] The narrowband module 68 includes two prisms 81, 82, a grating 83, and a rotation stage 84 that rotates the prism 82. The narrowband module 68 controls the oscillation wavelength of the pulsed laser light by rotating the prism 82 using the rotation stage 84, thereby changing the incident angle with respect to the grating 83. The rotation stage 84 can also be a rotation stage including a piezoelectric element that is capable of high-speed response in a manner that responds to each pulse.

[0145] The amplifier 24 includes an optical resonator 90, a cavity 160, a PPM 164, and a charger 166. The cavity 160, the PPM 164, and the charger 166 have the same structures as those of the corresponding elements of the oscillator 22. The cavity 160 includes windows 171, 172, a pair of electrodes 173, 174, and an electrically insulating member 175. The PPM 164 includes a switch 165 and a charging capacitor not shown.

[0146] The optical resonator 90 is a Fabry-Perot type optical resonator, which is constituted by a back mirror 91 and an output coupling mirror 92. The back mirror 91 partially reflects a part of the laser light and transmits another part. The output coupling mirror 92 partially reflects a part of the laser light and transmits another part. The reflectance of the back mirror 91 is, for example, 80% to 90%. The reflectance of the output coupling mirror 92 is, for example, 10% to 30%.

[0147] The monitor module 26 includes beam splitters 181, 182, a spectrum detector 183, and a light sensor 184 that detects the pulse energy E of the laser light. The spectrum detector 183 can be, for example, an etalon spectrometer or the like. The light sensor 184 can be, for example, a photodiode or the like.

[0148] 3.2.2 Action

[0149] The laser control section 20, after receiving the data of the target wavelength λt, the line width Δλt, and the target pulse energy Et from the exposure control section 40, controls the rotating stage 84 of the LNM 68 so that the output wavelength becomes the target wavelength λt, controls the mode described later so that it becomes the target line width Δλt, and controls at least the charger 166 of the amplifier 24 so that it becomes the target pulse energy Et.

[0150] The laser control section 20, after receiving the light emission trigger signal Tr from the exposure control section 40, gives the trigger signal to the switch 165 of the PPM 164 and the switch 65 of the PPM 64, respectively, so that discharge occurs when the pulse laser output from the oscillator 22 is incident to the discharge space of the cavity 160 of the amplifier 24. As a result, the pulse laser output from the oscillator 22 is amplified and oscillated by the amplifier 24. The amplified pulse laser is sampled by the beam splitter 181 of the monitor module 26, and the pulse energy E, the wavelength λ, and the line width Δλ are measured.

[0151] The laser control section 20 acquires the data of the pulse energy E, the wavelength λ, and the line width Δλ measured using the monitor module 26, and controls the charging voltage of the charger 166, the discharge timing of the oscillator 22 and the amplifier 24, and the oscillation wavelength of the oscillator 22 so that the difference between the pulse energy E and the target pulse energy Et, the difference between the wavelength λ and the target wavelength λt, and the difference between the line width Δλ and the target line width Δλt respectively approach 0.

[0152] The laser control section 20 can control the pulse energy E, the wavelength λ, and the line width Δλ in units of pulses. By controlling the delay time Δt of the discharge timing of the cavity 60 of the oscillator 22 and the cavity 160 of the amplifier 24, control of the line width Δλ of the pulse laser output from the laser device 12 can be performed.

[0153] The pulse laser that has passed through the beam splitter 181 of the monitor module 26 is incident to the exposure device 14 via the shutter 28.

[0154] 3.2.3 Others

[0155] In the Figure 8 , as the optical resonator 90, an example of a Fabry-Perot resonator is shown, but it can also be an amplifier having a ring resonator.

[0156] 3.3 Example of Focusing Curve of Mask Pattern

[0157] Figure 9 is a plan view schematically showing an example of a mask pattern. Figure 9The upper paragraph shows an example of the positional relationship between the mask 46 and the scanning beam SB at a certain moment t1 during a scanning exposure. Figure 9 The lower section shows an example of the positional relationship between the mask 46 and the scanning beam SB at time t2 (>t1). Figure 9 The direction from right to left (towards the negative side of the Y-axis) is the direction of mask movement. The scanning beam SB moves relative to the mask 46 in the direction towards the positive side of the Y-axis.

[0158] Various patterns exist in mask 46. Figure 9 The image shows an example of the configuration of three different patterns in the area. Figure 9 The PT(1), PT(2), and PT(3) in the text represent pattern (1), pattern (2), and pattern (3), respectively. In addition, the surrounding area of ​​pattern (1), pattern (2), and pattern (3) in the mask can be a patternless area or it can contain pattern (4) (the fourth pattern). Compared with pattern (1), pattern (2), and pattern (3), pattern (4) can be a pattern with a wider line width or a pattern with a lower line width requirement (wider allowable range).

[0159] exist Figure 9 In the example shown, the mask 46 corresponding to one scan field SF is divided into four parts, each segment corresponding to the circuit pattern of one chip. In each segment, the configuration of patterns (1), (2), and (3) is the same.

[0160] Mask 46 from Figure 9 Starting from the left, the area includes the first column of patterns formed by three patterns (1), (2), and (3) arranged side by side in the X-axis direction, the second column of patterns formed by two patterns (1) and (2) arranged side by side in the X-axis direction, the third column of patterns formed by three patterns (1), (2), and (3) arranged side by side in the X-axis direction, and the fourth column of patterns formed by two patterns (1) and (2) arranged side by side in the X-axis direction.

[0161] Here, examples are given of the first and third pattern groups, which are composed of combinations of three patterns (1), (2), and (3), and the second and fourth pattern groups, which are composed of combinations of two patterns (1) and (2). However, the combination of patterns, the arrangement of patterns, and the number of columns in the pattern groups are not limited to these examples. Figure 9 Examples.

[0162] Figure 10 The upper section shows the state of the scanning beam SB irradiating the first column of patterns. Figure 9The lower segment of FIG. 1 illustrates a state in which the scanning beam SB is irradiated to the 2nd column pattern group. The pattern groups of the columns configured to juxtapose a plurality of patterns in the X-axis direction mix two or more patterns within the region uniformly irradiated by the scanning beam SB.

[0163] Figure 10 The focus curves of the respective patterns (1) to (3) in the case 1 illustrated in the upper segment of FIG. 1 are exemplarily shown. Figure 10 The focus curve FC(1) of the pattern (1) illustrated in FIG. 2A shows the relationship between the focus position and the intensity of the reflected light. The focus curve FC(1) has a peak at the position of the best focus position BF(1). The best focus position BF(1) is a position at which the reflected light intensity is the highest. The best focus position BF(1) is a position at which the reflected light intensity is the highest. Figure 10 The best focus position BF(1) is grasped from the focus curve FC(1) of the pattern (1) illustrated in FIG. 2A. Similarly, the best focus positions BF(2) and BF(3) are respectively grasped from the focus curve FC(2) of the pattern (2) and the focus curve FC(3) of the pattern (3).

[0164] In the lithography control section 110 of the embodiment 1, the best wavelength λb is calculated so that the best focus position BF(1) of the pattern (1), the best focus position BF(2) of the pattern (2), and the best focus position BF(3) of the pattern (3) approach the focus position indicated by the dotted line in FIG. 1. Figure 11 The focus position indicated by the dotted line in FIG. 1 is the average of the best focus positions BF(1), BF(2), and BF(3). Figure 9 The focus position indicated by the dotted line in FIG. 1 is the average of the best focus positions BF(1), BF(2), and BF(3).

[0165] The best focus position BF(k) of the pattern (k) is a position at which the value of CD in the focus curve FC(k) becomes an extremum. When the wavelength λ of the pulsed laser is changed, each focus curve FC(k) changes, and the best focus position BF(k) also changes. The wavelength λ is changed, and BF(k) is calculated, whereby the wavelength λ at which the variance of BF(k) of the plurality of patterns (k) is the smallest can be found. The best focus position BF(k) is an example of the “best focus position corresponding to each of a plurality of patterns” in the present disclosure.

[0166] The variance is an index indicating the degree of dispersion (deviation situation) of data, and can be found by calculating the mean square of the deviation, for example, as defined in statistics. In addition, the variance can be calculated by multiplying a weight corresponding to the pattern.

[0167] Figure 11 The focus curves of the respective patterns (1) and (2) in the case 2 illustrated in the lower segment of FIG. 1 are exemplarily shown. The lithography control section 110 calculates the best wavelength λb for the combination of the pattern (1) and the pattern (2) so that the best focus position BF(1) grasped from the focus curve FC(1) and the best focus position BF(2) grasped from the focus curve FC(2) approach the position of the dotted line in the figure. Figure 12 The focus position indicated by the dotted line in FIG. 1 is the average of the best focus positions BF(1) and BF(2). Figure 12

[0168] ​Figure 12 An example of a relationship of the mask pattern, the optimum wavelength λb, and the target wavelength λt is shown. Figure 12 The upper paragraph shows a plan view that schematically shows a relationship of the mask pattern and the scan beam SB. Here, a case where the scan beam SB is irradiated to the 1st column pattern group of the mask 46 is shown. The scan beam SB is moved in scanning with respect to the mask 46 toward the positive side of the Y-axis direction.

[0169] The Y-axis direction width of each of the regions of the patterns (1), (2), (3) in the 1st column pattern group of the mask 46 is set to Wy1, and the Y-axis direction width of each of the regions of the patterns (1), (2) in the 2nd column pattern group is set to Wy2. The Y-axis direction beam width (By width) of the scan beam SB can be a value smaller than each of the values of Wy1 and Wy2.

[0170] In the upper paragraph of Figure 12 A graph G1 showing a relationship of the Y-axis direction position within one scan and the optimum wavelength λb is shown in the frame shown in the middle paragraph of Figure 13 A graph G2 showing the target wavelength λt of each scan exposure pulse corresponding to the Y-axis direction position within one scan is shown in the frame shown in the lower paragraph of Figure 14 An example in which the exposure control section 40 reads in the data of the file B generated by the lithography control section 110, uses the value of the optimum wavelength λb corresponding to each of the combined regions of the patterns (1) to (3), and directly sends the value as the target wavelength λt to the laser control section 20 is shown in the middle paragraph. The sending of the target wavelength λt to the laser control section 20 is an example of "indicating the target wavelength of the pulsed laser to the laser device" in the present disclosure.

[0171] 3.4 Example of processing content of the lithography control section

[0172] Figure 13 and Figure 14 is a flowchart showing an example of the processing performed by the lithography control section 110 of Embodiment 1. A processor that functions as the lithography control section 110 executes a program, whereby the steps shown in Figure 15 and Figure 9 are implemented.

[0173] In step S10, the lithography control section 110 receives input of data of each parameter including a parameter of the illumination optical system 44, a parameter of the projection optical system 50 including a wavefront aberration, and a parameter of the resist.

[0174] The parameter of the illumination optical system 44 includes, for example, a σ value, an illumination shape, and the like. The parameter of the projection optical system 50 includes, for example, lens data, an NA of a lens, a wavefront aberration, and the like. The parameter of the resist includes, for example, a sensitivity, and the like.

[0175] In step Sll, the lithography control section 110 sets λ0 for the wavelength λ(l). λ0 can be a value determined in advance. In step S12, the lithography control section 110 sets the index k, which corresponds to the pattern number indicating the kind of the reticle pattern, to the initial value of 1.

[0176] Next, in step S13, the lithography control section 110 receives input of information defining the geometric dimensions of the three-dimensional structure of the reticle pattern (k) and the material property values. An example of the processing contents of step S13 uses the following formula. Figure 14 The details will be described later.

[0177] In step S14, the lithography control section 110 sets the index m of the wavelength to the initial value of 1. Next, in step S15, the lithography control section 110 sets the initial values of the control parameters of the laser light. The control parameters of the laser light here can be, for example, the wavelength λ(m), the spectral line width Δλ, and the exposure amount (dose) D, and the like. In addition, instead of or in addition to the exposure amount D, the pulse energy E can be used.

[0178] The relationship between the exposure amount D on the wafer surface and the pulse energy E is expressed by the following formula.

[0179] D = T • E • N SL / (Bx • By)

[0180] T in the formula is the transmittance from the laser device 12 to the wafer WF.

[0181] The formula can be transformed as follows.

[0182] E = D • (Bx • By) / (T • N SL )

[0183] In step S16, the lithography control section 110 calculates the focus curve FC(k, m) from the input data. That is, the lithography control section 110 calculates the focus curve FC(k, m) corresponding to the reticle pattern (k) and the wavelength λ(m) according to the calculation program according to the conditions provided.

[0184] In step S17, the lithography control section 110 calculates the optimum focus position BF(k, m) from the focus curve FC(k, m) calculated in step S16.

[0185] In step S18, the lithography control section 110 writes the wavelength λ(m) and the optimum focus position BF(k, m) in the case of the reticle pattern (k) and the wavelength λ(m) in the file A.

[0186] Next, in step S19, the lithography control section 110 determines whether the value of the index m coincides with Mmax. Mmax is the upper limit value (maximum value) of the value of m, and is a value determined in advance.

[0187] When the determination result in step S19 is "NO", the lithography control section 110 proceeds to step S20, and increases the value of m. Next, in step S21, the lithography control section 110 changes the wavelength λ(m) according to the equation λ(m) = λ(m - 1) + δλ, and returns to step S15. Here, δλ is the amount of change (scale) of the wavelength when the wavelength is changed. The lithography control section 110 changes the wavelength in units of the predetermined change amount δλ. The processing of steps S15 to S21 is performed a plurality of times while changing the value of the wavelength λ(m), until the value of m reaches Mmax.

[0188] When the determination result in step S19 is "YES", the lithography control section 110 proceeds to step S22. In step S22, the lithography control section 110 determines whether the value of the index k coincides with Kmax. Kmax is the upper limit value (maximum value) of the value of k, and is a predetermined value. In the example of FIG. 10, Kmax = 3. Figure 13

[0189] When the determination result in step S22 is "NO", the lithography control section 110 proceeds to step S23, increases the value of k, and returns to step S13. The processing of steps S13 to S23 is performed a plurality of times while changing the value of k, until the value of k reaches Kmax.

[0190] When the determination result in step S22 is "YES", the lithography control section 110 proceeds to step S24. Figure 14

[0191] In step S24, the lithography control section 110 calculates the variance value S of each optimum focus position with respect to each combination of the reticle pattern and the wavelength λ(m).

[0192] Then, in step S25, the lithography control section 110 writes the variance value S of the calculation result in step S24 in the file A.

[0193] Next, in step S26, the lithography control section 110 finds λ(m) in the case where the variance value is the smallest in each combination of the patterns (1), (2), and (3) respectively, from the calculation data of the file A.

[0194] Then, in step S27, the lithography control section 110 saves the data of the calculation result in step S26 in the file B.

[0195] After step S27, the lithography control section 110 ends the flowchart of FIG. 10. Figure 15 and Figure 13

[0196] Figure 16 is a flowchart showing the process of the lithography control section 110. Figure 17 ​​​A flowchart illustrating an example of the processing content in step S13. In step S31, the photolithography control unit 110 inputs information defining the geometric dimensions of the three-dimensional structure of the mask pattern into a photolithography simulation program that includes electromagnetic field analysis functionality. Geometric dimensions include, for example, the X-axis width Lk of the line portion of each pattern, the X-axis width Sk of the spacing portion, the thickness hj of each layer (layer) of the three-dimensional structure in each pattern, and the Y-axis width Wk of the line portion of each pattern, etc. (see reference). Figure 15 and Figure 13 Additionally, the subscript "j" in thickness hj indicates the layer number of the layer structure.

[0197] In step S32, the photolithography control unit 110 inputs the physical property values ​​(n(λ), k(λ)) of the material constituting each pattern, including the refractive index n(λ) and extinction coefficient k(λ) of air, into the photolithography simulation program that includes electromagnetic field analysis function.

[0198] In step S33, the photolithography control unit 110 receives input information on the wavelength of the illumination light (laser) and the incident angle relative to the mask 46.

[0199] In step S34, the lithography control unit 110 inputs the output of the calculation results (phase and amplitude of diffracted light) of the lithography simulation program, which includes electromagnetic field analysis function, into the focusing calculation routine of the next step.

[0200] After step S34, the photolithography control unit 110 ends. Figure 13-15 The flowchart, return Figure 16 The main process. Following... Figure 17 The flowchart for determining the optimal wavelength as a laser control parameter is an example of the "Method for Generating Laser Control Parameters" in this disclosure.

[0201] Figure 16 It is a top view schematically showing a portion of the mask pattern. Figure 17 It is Figure 17 Line 17-17 is set as a section line in the sectional view. Additionally, in... Figure 16 In the illustration, a two-layer structure is shown as an example of a patterned stacked structure; however, the patterned stacked structure in mask 46 can also have three or more layers. The substrate 46a of mask 46 can, for example, be synthetic quartz.

[0202] Figure 17 The description of (n0, k0) indicates that the refractive index of the synthetic quartz is n0 and the extinction coefficient is k0. Figure 16 and Figure 17 The first layer of the pattern shown has a refractive index of n1, an extinction coefficient of k1, and a thickness of h1. The second layer has a refractive index of n2, an extinction coefficient of k2, and a thickness of h2. (The text repeats itself here.)Figure 18 and Figure 18 As shown, L1, S1, L2, S2, ..., h1, h2, ..., W1, W2..., which serve as examples of geometric dimensions, represent the dimensions of each element in the three-dimensional structure of the pattern.

[0203] Figure 18 This is a diagram illustrating an example of the data stored in document A. In document A, data on the optimal focus position for each pattern at each wavelength λ (m) and the variance of the optimal focus in various combinations of multiple patterns are stored in tabular form. Document A is an example of "Document 1" in this disclosure.

[0204] Based on the data in document A, it is possible to determine the wavelength that minimizes the variance for each combination of various patterns to achieve optimal focus. Figure 19 The notation “pattern(1)(2)(3)” in the text represents the combination of the three patterns (1), (2) and (3).

[0205] The notation “pattern(1)(2)” represents a combination of patterns (1) and (2). The notation “pattern(1)(3)” represents a combination of patterns (1) and (3). The notation “pattern(2)(3)” represents a combination of patterns (2) and (3).

[0206] For example, in Figure 18 In the above, let S be the variance of the optimal focus related to the combination of patterns (1)(2)(3). 123 Data group {S 123 (1) S 123 (2), ...S 123 The minimum value in (Mmax)} is S. 123 (3) When the variance S is... 123 The minimum wavelength is λ(3). Similarly, let the variance S of the optimal focus related to the combination of patterns (1) and (2) be... 12 The minimum value is S 12 (4) When the variance S 12 The minimum wavelength is λ(4). Let S be the variance of the optimal focus related to the combination of patterns (1) and (3). 13 The minimum value is S 13 When (m), the variance S 13 The minimum wavelength is λ (m). Let S be the variance of the optimal focus related to the combination of patterns (2) and (3). 23 The minimum value is S 23 (2) When the variance value S is... 23 The minimum wavelength is λ(2).

[0207] Thus, the wavelength (optimum wavelength λb) at which the variance value S of the optimum focus is the smallest can be found for each combination of patterns. Data in which the correspondence between the combination of patterns and the optimum wavelength λb at which the variance value S of the optimum focus is the smallest is collected is saved in a file B.

[0208] Figure 20 is a graph showing an example of the data saved in the file B. In the file B, data of the optimum wavelength λb for each combination of patterns is saved in the form of a table. In the example explained in Figure 20 , the optimum wavelength λb for the combination of patterns (1) (2) (3) is λ(3). Further, the optimum wavelength λb for the combination of patterns (1) (2) is λ(4), the optimum wavelength λb for the combination of patterns (1) (3) is λ(m), the optimum wavelength λb for the combination of patterns (2) (3) is λ(2). The file B is an example of the "second file" and the "file" in the present disclosure. 123 12 13 23 The file B is an example of the "second file" and the "file" in the present disclosure.

[0209] 3.5 Example of processing content of exposure control section

[0210] Figure 20 is a flowchart showing an example of the processing implemented by the exposure control section 40 of Embodiment 1. The processor that functions as the exposure control section 40 executes a program, whereby the steps shown in Figure 21 are implemented.

[0211] In step S41, the exposure control section 40 reads in the data of the file B saved in the lithography control section 110.

[0212] In step S42, the exposure control section 40 calculates the target value (here, the target wavelength λt) of the control parameter of the laser light of each pulse in each scan field SF from the data of the file B and the positions of the patterns (1), (2), and (3) in the scan field SF.

[0213] In step S43, the exposure control section 40 moves the reticle 46 and the wafer WF while sending the target value of the control parameter of the laser light of each pulse and the light emission trigger signal Tr to the laser control section 20, and exposes each scan field SF.

[0214] In step S44, the exposure control section 40 determines whether or not all of the scan fields SF in the wafer WF have been exposed. In the case where the determination result in step S44 is "No", the exposure control section 40 returns to step S43. In the case where the determination result in step S44 is "Yes", the exposure control section 40 ends the flowchart of Figure 21 . ​​​

[0215] 3.6 Examples of processing contents of the laser control section

[0216] Figure 21 is a flowchart showing an example of the processing performed by the laser control section 20 of Embodiment 1. The processor functioning as the laser control section 20 executes the program, whereby the processing shown in the flowchart is realized. Figure 13

[0217] In step S51, the laser control section 20 reads in the data of the control parameters (λt, Δλt, Et) of the target laser light transmitted from the exposure control section 40.

[0218] In step S52, the laser control section 20 sets the rotation stage 84 of the narrowbanding module 68 of the oscillator 22 so as to make the wavelength λ of the pulsed laser light output from the laser device 12 approach the target wavelength λt.

[0219] In step S53, the laser control section 20 sets the synchronization timing of the oscillator 22 and the amplifier 24 so as to make the spectral linewidth Δλ of the pulsed laser light output from the laser device 12 approach the target spectral linewidth Δλt.

[0220] In step S54, the laser control section 20 sets the charging voltage of the amplifier 24 so as to make the pulse energy E approach the target pulse energy Et.

[0221] In step S55, the laser control section 20 waits for the input of the light emission trigger signal Tr, and determines whether the light emission trigger signal Tr has been input. If the light emission trigger signal Tr has not been input, the laser control section 20 repeatedly performs step S55, and after the light emission trigger signal Tr has been input, the laser control section 20 proceeds to step S56.

[0222] In step S56, the laser control section 20 measures the data of the control parameters of the laser light using the monitor module 26. The laser control section 20 acquires the data of the wavelength λ, the spectral linewidth Δλ, and the pulse energy E by the measurement in step S56.

[0223] In step S57, the laser control section 20 transmits the data of the control parameters of the laser light measured in step S56 to the exposure control section 40 and the lithography control section 110.

[0224] In step S58, the laser control section 20 determines whether to stop the control of the laser light. In the case where the determination result of step S58 is "No", the laser control section 20 returns to step S51. In the case where the determination result of step S58 is "Yes", the laser control section 20 ends the flowchart of Fig. 8. Figure 14

[0225] 3.7 Effects / Advantages

[0226] ​​According to the photolithography system 100 of Embodiment 1, the wavelength of the pulsed laser is adjusted for combinations of multiple patterns to reduce the optimal focus difference between patterns. According to Embodiment 1, the optimal focus difference between patterns based on the three-dimensional effect of the mask can be reduced, thus improving the CDU (Current Distance Difference).

[0227] 3.8 Other

[0228] This section explains the correction of optimal focus difference based on the three-dimensional effect of the mask. However, it can also be applied to the correction of optimal focus difference between patterns based on the wavefront aberration of the projection optical system 50 and optimal focus difference between patterns based on the resist film thickness effect.

[0229] In Embodiment 1, an example was described in which the functions of the lithography control unit 110 and the exposure control unit 40 are separated. However, it is not limited to this example, and the exposure control unit 40 may also include the functions of the lithography control unit 110.

[0230] also, Figure 19 and Figure 13 The calculation process shown can also be pre-calculated using a computer equipped with a calculation program. Figure 14 Such a file B is stored in the storage unit of the lithography control unit 110 or the exposure control unit 40. The lithography control unit 110 may also be a server that manages various parameters used in scanning exposure. The server may also be connected to multiple exposure systems via a network. For example, the server is configured to implement... Figure 22 and Figure 22 This calculation process writes the calculated control parameter values ​​into file B.

[0231] 4. Implementation Method 2

[0232] 4.1 Structure

[0233] The structure of the lithography system in Embodiment 2 can be the same as that in Embodiment 1.

[0234] 4.2 Actions

[0235] Figure 12 An example is shown illustrating the relationship between the mask pattern in the photolithography system of Embodiment 2 and the optimal wavelength λb, the target wavelength λt, and the wavelength λ of the cumulative spectrum. Regarding... Figure 22 , to Figure 12 The differences will be explained. Figure 22 In, replacing Figure 12 The curve G2 becomes curve G4. Figure 22 The bottom box shows graph G5, which represents the wavelength λ of the cumulative spectrum of the scan exposure pulse corresponding to the Y-axis position within one scan.

[0236] The moving direction of the reticle 46 in the scan exposure is the negative direction of the Y axis. Here, the description is made assuming that the scan beam SB moves in the positive direction of the Y axis with respect to the reticle 46.

[0237] The graph G4 is changed from the graph G2 of Figure 23 so that the timing at which the value of the target wavelength λt is switched becomes the timing at which the Y axis direction beam width (By width) of the scan beam SB is advanced more to the negative side (the front side) than the Y axis direction negative side boundary position of the region of each pattern (1) to (3). This corresponds to setting the same target wavelength λt for an imaginary expanded region in which the boundary region is expanded to a band-shaped region corresponding to the By width from the Y axis direction negative side boundary position of the region of each pattern to the Y axis direction negative side.

[0238] In addition, the scan beam SB illuminated onto the reticle 46 becomes a scan beam of a size corresponding to the magnification of the projection optical system 50 of the exposure apparatus 14 on the wafer WF. For example, in the case where the magnification of the projection optical system 50 is 1 / 4 times, the scan beam SB illuminated onto the reticle 46 becomes a scan beam of a size of 1 / 4 times on the wafer WF. Further, the scan field region on the reticle 46 becomes a scan field SF of 1 / 4 times thereof on the wafer WF. The Y axis direction beam width (By width) of the scan beam SB illuminated onto the reticle 46 is a beam width that realizes the Y axis direction width By of the static exposure region SEA on the wafer WF.

[0239] In the flowchart shown in the lowermost row of Figure 23 , a graph G5 showing the wavelength λ of the cumulative spectrum of each scan exposure pulse corresponding to the Y axis direction position within the 1st scan field SF is shown.

[0240] The target wavelength λt is set as shown in the graph G4, whereby the wavelength λ of the cumulative spectrum is constant in the region range of each pattern group of the 1st column to the 4th column as shown in the graph G5.

[0241] Figure 20 is a flowchart showing an example of the processing implemented by the exposure control section 40 of Embodiment 2. The flowchart shown in Figure 23 is different from the flowchart shown in Figure 20 . Figure 20 The flowchart shown in Figure 24 adds a step S40 before the step S41 and includes a step S42b instead of the step S42 in

[0242] In step S40, the exposure control section 40 expands the boundary region of the Y-axis direction negative side of each of the regions of the patterns (1) to (3) to the Y-axis direction negative side by the By width of the scan beam SB, and obtains each region. That is, the Y-axis direction negative side boundary position of each region is moved by a distance corresponding to the By width, and each region is changed to an expanded region, in a manner such that the range of each of the regions of the patterns (1) to (3) is expanded to the Y-axis direction negative side by an amount corresponding to the beam width of the scan beam SB. The boundary region added to the Y-axis direction negative side of each region by the By width is referred to as a "shift region".

[0243] In step S42b, the exposure control section 40 calculates the target value of the control parameter of the laser of each pulse (here, at least the target wavelength λt) in each scan field SF, based on the data of the file B, the patterns (1), (2), and (3) in the scan field SF, and the position of each of the expanded regions. Steps S43 and subsequent steps are the same as in Embodiment 1. Figure 7

[0244] 4.3 Action / Effect

[0245] The wavelength λ of the pulsed laser exposed to the scan field SF becomes the wavelength λ of the movement cumulative spectrum of the exposure pulse number N SL . According to Embodiment 2, the wavelength λ of the movement cumulative spectrum of the pulsed laser irradiated to each of the regions of the patterns (1), (2), and (3) becomes the optimum wavelength λb, and each of the patterns (1) to (3) can be exposed using the optimum wavelength λb.

[0246] 5. Embodiment 3

[0247] 5.1 Configuration

[0248] Figure 18 A configuration example of the lithography system 103 of Embodiment 3 is shown. The lithography system 103 of Embodiment 3 is a configuration in which a wafer inspection device 310 is added to the configuration of Figure 18 . The other configurations can be the same as in Embodiment 1. The wafer inspection device 310 irradiates laser light on the wafer WF, and measures the reflected light or the diffracted light, whereby CD, focus, and overlay can be measured. Alternatively, the wafer inspection device 310 can be a high-resolution scanning electron microscope (SEM). The wafer inspection device 310 includes a wafer inspection control section 320, a wafer holder 352, and a wafer stage 354. The wafer inspection device 310 is an example of the "inspection device" in the present disclosure.

[0249] The lithography control section 110 is connected with a line that transmits and receives data and the like between the lithography control section 110 and the wafer inspection control section 320.

[0250] 5.2 Action​

[0251] The lithography control section 110 causes the wafer inspection device 310 to inspect the exposed wafer WF. The lithography control section 110 associates each parameter using the pattern and CD value at each position on the wafer WF measured by the wafer inspection device 310, and the wavelength λ and focus position F of the laser light exposed at each position. The expression "associates" is synonymous with the expression "correlates" or "corresponds". The exposed wafer WF that becomes the inspection target of the wafer inspection device 310 is an example of the "exposed semiconductor substrate" in the present disclosure.

[0252] The lithography control section 110 calculates the optimum focus position BF(k, m) for each pattern (k) from the focus curve after exposure for each wavelength λ (m), based on the result of actually exposing the wafer WF, and saves the data in the file A. Figure 25 The file A.

[0253] The lithography control section 110 calculates the optimum focus position BF(k, m) for each pattern (k) from the focus curve after exposure for each wavelength λ (m), based on the result of actually exposing the wafer WF, and saves the data in the file A. Figure 25 The file A.

[0254] Figure 8 is a flowchart showing an example of the processing in the lithography control section 110 of Embodiment 3. In step S60, the lithography control section 110 transmits a measurement signal of the wafer WF to the wafer inspection device 310. The wafer inspection device 310 performs measurement according to the measurement signal from the lithography control section 110.

[0255] In step S61, the lithography control section 110 determines whether or not the inspection of the wafer WF is completed. For example, the wafer inspection device 310 transmits an inspection completion signal indicating that the inspection is completed to the lithography control section 110 after completing the inspection of the wafer WF. The lithography control section 110 determines whether or not the inspection is completed according to whether or not the reception of the inspection completion signal is performed.

[0256] In the case where the determination result of step S61 is "No", the process waits in this step. In the case where the determination result of step S61 is "Yes", the lithography control section 110 proceeds to step S62.

[0257] In step S62, the lithography control section 110 receives the pattern and CD value at each position of the exposed wafer WF from the wafer inspection device 310. As for the information on the pattern, the data of the reticle pattern can also be stored in advance in the case where it is difficult to obtain from the measurement result of the wafer inspection device 310.

[0258] In step S63, the lithography control section 110 associates the pattern (k), the wavelength λ (m) of exposure, and the CD value corresponding to the focus, based on the wafer inspection data.

[0259] Next, in step S64, the lithography control section 110 calculates the optimum focus position BF (k, m) based on the focus curve corresponding to each pattern (k) and each wavelength λ (m).

[0260] Next, in step S65, the lithography control section 110 saves the data of the optimum focus position BF for each pattern and each wavelength in file A.

[0261] Next, in step S66, the lithography control section 110 calculates the variance value S of the optimum focus for each combination of pattern and wavelength λ (m). Then, in step S67, the lithography control section 110 saves the data of the variance value S calculated in file A.

[0262] Next, in step S68, the lithography control section 110 calculates λb as the optimum wavelength for which the variance value S of the optimum focus is the smallest, for each combination of pattern. Then, in step S69, the lithography control section 110 saves the data of the optimum wavelength λb in file B for each combination of pattern.

[0263] After step S69, the lithography control section 110 ends the flowchart. Figure 8

[0264] 5.3 Action / Effect

[0265] According to the lithography system 103 of Embodiment 3, the correction of the focus offset between the reticle patterns based on the three-dimensional effect of the reticle can be performed based on the result of actually exposing the wafer WF. As a result, in the scan exposure, the wavelength of the pulsed laser is adjusted corresponding to the combination of the patterns, according to the position of the reticle pattern, whereby the correction of the focus offset between the reticle patterns based on the three-dimensional effect of the reticle can be performed.

[0266] Further, according to Embodiment 3, the data of each of file A and file B can be updated based on the result of actual exposure, and thus the optimum wavelength can be used for exposure in the exposure process at that point. As a result, the CDU of the resist pattern is improved.

[0267] 5.4 Other

[0268] In Embodiment 3, test exposure can be initially performed, and thus the data of the initial file A and file B can be generated. The process of generating the data of file A and file B by performing test exposure is, for example, as follows.

[0269] ​[Process a] The target wavelength λt of the laser device 12 and the focus position of the exposure device 14 are changed for each scan of the wafer WF, and exposure is performed.

[0270] [Process b] The initial file A and the file B can also be generated based on the inspection result of the wafer WF exposed in process a, the wavelength and the focus position at that time.

[0271] 6. Variance of the optimum focus position of each pattern

[0272] The variance of the optimum focus position of each pattern included in the combination of the plurality of patterns is not limited to the arithmetic average of the squares of the deviations, and the variance value can also be calculated by adding a weight to the pattern. For example, in calculating the sum of the squares of the deviations, a weight reflecting the importance can also be added according to the type of the circuit to calculate the variance value. Further, weighting corresponding to the area ratio of the pattern can also be performed, and the weight is increased for a pattern occupying a relatively large area to calculate the variance value. Alternatively, further, the weight can also be increased for a pattern having an important influence on the operation of the circuit (for example, a circuit portion of a gate circuit) to calculate the variance value.

[0273] The standard deviation is defined as the positive square root of the variance, and thus the minimum variance means the minimum standard deviation. There is no essential difference between using the variance and using the standard deviation as a value evaluating the degree of dispersion of data, and it is obvious that the evaluation of the variance can be replaced by the evaluation of the standard deviation in the present specification.

[0274] 7. Example of excimer laser device using solid-state laser device as oscillator

[0275] 7.1 Configuration

[0276] Figure 8 The laser device 12 described in the above is an example of a configuration using a narrowband gas laser device as an oscillator 22, but the configuration of the laser device is not limited to Figure 26 .

[0277] Instead of the laser device 12 shown in Figure 26 , the laser device 212 shown in Figure 8 may be used. Regarding the configuration shown in Figure 26 , the same or similar elements as those in Figure 27 are labeled with the same reference numerals and the description thereof is omitted.

[0278] Figure 27-30 The laser device 212 shown in is an excimer laser device using a solid-state laser device as an oscillator, and includes a solid-state laser system 222, an excimer amplifier 224, and a laser control section 220.

[0279] The solid laser system 222 includes a semiconductor laser system 230, a titanium-doped sapphire amplifier 232, a pump pulse laser 234, a wavelength conversion system 236, and a solid laser control section 238.

[0280] The semiconductor laser system 230 includes a distributed feedback (DFB) semiconductor laser that outputs CW laser light having a wavelength of approximately 773.6 nm, and a semiconductor optical amplifier (SOA) that pulses the CW laser light. An example of the configuration of the semiconductor laser system 230 uses a DFB semiconductor laser that outputs CW laser light having a wavelength of approximately 773.6 nm, and a SOA that pulses the CW laser light. Figure 27 This will be described later.

[0281] The titanium-doped sapphire amplifier 232 includes a titanium-doped sapphire crystal. The titanium-doped sapphire crystal is disposed in the optical path of the pulsed laser light that is amplified by the SOA of the semiconductor laser system 230. The pump pulse laser 234 can also be a laser device that outputs the 2nd harmonic light of a YLF laser. YLF (yttrium lithium fluoride) is a solid laser crystal represented by the chemical formula LiYF4.

[0282] The wavelength conversion system 236 includes a plurality of nonlinear optical crystals that wavelength-convert the incident pulsed laser light and output 4th harmonic pulsed laser light. The wavelength conversion system 236 includes, for example, an LBO crystal and a KBBF crystal. The LBO crystal is a nonlinear optical crystal represented by the chemical formula LiB3O5. The KBBF crystal is a nonlinear optical crystal represented by the chemical formula KBe2BO3F2. Each crystal is disposed on a not-shown rotation stage and configured to be able to change the incident angle with respect to the crystal.

[0283] The solid laser control section 238 controls the semiconductor laser system 230, the pump pulse laser 234, and the wavelength conversion system 236 in accordance with the instructions from the laser control section 220.

[0284] The excimer amplifier 224 includes a cell 160, a PPM 164, a charger 166, a convex mirror 241, and a concave mirror 242. The cell 160 includes windows 171, 172, a pair of electrodes 173, 174, and an electrically insulating member 175. An ArF laser gas is introduced into the cell 160. The PPM 164 includes a switch 165 and a charge capacitor.

[0285] The excimer amplifier 224 is configured to pass the seed light having a wavelength of 193.4 nm three times in the discharge space between the pair of electrodes 173, 174 and amplify it. Here, the seed light having a wavelength of 193.4 nm is the pulsed laser light output from the solid laser system 222.

[0286] The convex mirror 241 and the concave mirror 242 are configured to make the pulsed laser output from the solid laser system 222 outside the cavity 160 to pass through 3 times for beam expansion.

[0287] The seed light of the wavelength of about 193.4 nm incident to the excimer amplifier 224 is reflected by the convex mirror 241 and the concave mirror 242, thereby passing through 3 times in the discharge space between the pair of discharge electrodes 412, 413. As a result, the beam of the seed light is expanded and amplified.

[0288] 7.2 Action

[0289] The laser control section 220, upon receiving the target wavelength λt, the target spectral width Δλt, and the target pulse energy Et from the exposure control section 40, calculates the target wavelength λ1ct and the target spectral width Δλ1cht of the pulsed laser from the semiconductor laser system 230 to become these target values, for example, according to table data or an approximate formula.

[0290] The laser control section 220 transmits the target wavelength λ1ct and the target spectral width Δλ1cht to the solid laser control section 238, and sets the charging voltage to the charger 166 so that the pulsed laser output from the excimer amplifier 224 becomes the target pulse energy Et.

[0291] The solid laser control section 238 controls the semiconductor laser system 230 so that the pulsed laser output from the semiconductor laser system 230 approaches the target wavelength λ1ct and the target spectral width Δλ1cht. The manner of the control performed by the solid laser control section 238 uses Figure 28 This will be described later.

[0292] Further, the solid laser control section 238 controls two rotary stages not shown so as to become the incident angle at which the wavelength conversion efficiency of the LBO crystal and the KBBF crystal of the wavelength conversion system 236 is the largest.

[0293] After the emission trigger signal Tr is transmitted from the exposure control section 40 to the laser control section 220, a trigger signal is input to the switch 165 of the PPM 164 of the semiconductor laser system 230, the pulsed laser for pumping 234, and the excimer amplifier 224 in synchronization with the emission trigger signal Tr. As a result, a pulsed current is input to the SOA of the semiconductor laser system 230, and a pulsed laser amplified after the pulsed current is output from the SOA.

[0294] The pulsed laser is output from the semiconductor laser system 230, and is further amplified in the titanium-doped sapphire amplifier 232. The pulsed laser is incident to the wavelength conversion system 236. As a result, a pulsed laser of the target wavelength λt is output from the wavelength conversion system 236.

[0295] The laser control section 220 sends a trigger signal to the SOA 260, the switch 165 of the PPM 164, and the pump pulse laser 234 of the semiconductor laser system 230, respectively, after receiving the light emission trigger signal Tr from the exposure control section 40, to cause discharge when the pulse laser output from the solid laser system 222 is incident on the discharge space of the cavity 160 of the excimer amplifier 224.

[0296] As a result, the pulse laser output from the solid laser system 222 is amplified in the excimer amplifier 224 by 3 passes. The pulse laser amplified by the excimer amplifier 224 is sampled by the beam splitter 181 of the monitor module 26, and the pulse energy E is measured using the optical sensor 184, and the wavelength λ and the spectral width Δλ are measured using the spectrum detector 183.

[0297] The laser control section 220 can also perform correction control of the charging voltage of the charger 166, the wavelength λ1ct and the spectral width Δλ1cht of the pulse laser output from the semiconductor laser system 230, respectively, based on the pulse energy E, the wavelength λ, and the spectral width Δλ measured using the monitor module 26, so that the difference between the pulse energy E and the target pulse energy Et, the difference between the wavelength λ and the target wavelength λt, and the difference between the spectral width Δλ and the target spectral width Δλt, respectively, approach 0.

[0298] 7.3 Description of Semiconductor Laser System

[0299] 7.3.1 Configuration

[0300] Figure 29 A configuration example of the semiconductor laser system 230 is shown. The semiconductor laser system 230 includes a single-longitudinal-mode distributed feedback type semiconductor laser 250, a semiconductor optical amplifier (SOA) 260, a function generator (FG) 262, a beam splitter 264, a spectrum monitor 266, and a semiconductor laser control section 268. The distributed feedback type semiconductor laser is referred to as a "DFB laser".

[0301] The DFB laser 250 outputs CW (Continuous Wave) laser having a wavelength of about 773.6 nm. The DFB laser 250 is capable of changing the oscillation wavelength by current control and / or temperature control.

[0302] The DFB laser 250 includes a semiconductor laser element 251, a Peltier element 252, a temperature sensor 253, a temperature control section 254, a current control section 256, and a function generator 257. The semiconductor laser element 251 includes a first cladding layer 271, an active layer 272, and a second cladding layer 273, and includes a grating 274 at the boundary between the active layer 272 and the second cladding layer 273.

[0303] 7.3.2 Action

[0304] As for the oscillation center wavelength of the DFB laser 250, the wavelength can be changed by varying the set temperature T and / or the current value A of the semiconductor laser element 251.

[0305] In a case where the oscillation wavelength of the DFB laser 250 is chirped at high speed to control the spectral linewidth, the spectral linewidth can be controlled by varying the current value A of the current flowing in the semiconductor laser element 251 at high speed.

[0306] That is, the DC component value Al dc, the variation amplitude Al ac of the AC component, the period Al ac of the AC component, and the DC component value Al dc, the variation amplitude Al ac of the AC component, the period Al ac of the AC component are transmitted from the semiconductor laser control section 268 to the function generator 257. T The values of the parameters serve as current control parameters, and thus the center wavelength λl chc and the spectral linewidth Δλl ch of the pulsed laser light output from the semiconductor laser system 230 can be controlled at high speed.

[0307] The spectrum monitor 266 can measure the wavelength using, for example, a spectrometer or a heterodyne interferometer.

[0308] The function generator 257 outputs an electric signal of a waveform corresponding to the current control parameters specified by the semiconductor laser control section 268 to the current control section 256. The current control section 256 performs current control so that a current corresponding to the electric signal from the function generator 257 flows in the semiconductor laser element 251. In addition, the function generator 257 can be provided outside the DFB laser 250. For example, the function generator 257 can be included in the semiconductor laser control section 268.

[0309] Figure 29 is a conceptual diagram of the spectral linewidth achieved by chirping. The spectral linewidth Δλl ch is measured as the difference between the maximum wavelength and the minimum wavelength generated by chirping.

[0310] Figure 29 is a schematic diagram showing the relationship between the current flowing in the semiconductor laser, the wavelength variation based on chirping, the spectral waveform, and the light intensity. Figure 29 The graph GA shown in the lower left part of is a graph showing the variation of the current value A of the current flowing in the semiconductor laser element 251. Figure 29 The graph GB shown in the lower center part of is a graph showing the chirp generated by the current of the graph GA. Figure 29 The graph GC shown in the upper part of is a schematic diagram of the spectral waveform obtained by the chirp of the graph GB. Figure 30The graph GD shown on the lower right is a graph showing the change in the light intensity of the laser output from the semiconductor laser system 230 as a result of the current passing through graph GA.

[0311] The current control parameters of the semiconductor laser system 230, as shown in graph GA, include the following values.

[0312] A1dc: The DC component of the current flowing through the semiconductor laser element.

[0313] A1ac: The variation in the AC component of the current flowing through a semiconductor laser element (the difference between the maximum and minimum values ​​of the current).

[0314] A1 T The period of the AC component of the current flowing through a semiconductor laser element.

[0315] exist Figure 29 In the examples shown, the AC component, which is a current control parameter, is an example of a triangular wave, illustrating how variations in the current through the triangular wave result in minimal changes in the intensity of the CW laser output from the DFB laser 250.

[0316] Here, the preferred amplification pulse duration D of SOA260 is... TW Period A1 of AC component T The relationship satisfies the following equation (1).

[0317] D TW =n·A1 T (1)

[0318] n is an integer greater than or equal to 1.

[0319] By satisfying the relationship in equation (1), the SOA260 can suppress the change in the spectral waveform of the amplified pulsed laser regardless of when pulse amplification is performed.

[0320] Furthermore, even if equation (1) is not satisfied, the pulse width range in SOA260 is, for example, 10 ns to 50 ns. The period A1 of the AC component of the current flowing in the semiconductor laser element 251 is... T It is much shorter than the pulse width of SOA260 (the time width D of the amplified pulse). TW The period of ). For example, the period A1 is preferred. T The pulse width is greater than 1 / 1000 and less than 1 / 10 compared to that in SOA260. More preferably, it is greater than 1000 and less than 1 / 100.

[0321] Furthermore, the rise time of SOA260 is preferably 2ns or less, and more preferably 1ns or less.Figure 26-30 As shown, the rise time here refers to the time Rt required for the amplitude in the waveform of the pulsed current to increase from 10% to 90% of the maximum amplitude.

[0322] 7.3.3 Others

[0323] In Figure 26 In the example shown, as an example of the waveform of the AC component of the current, a triangular wave is shown, but is not limited to this example, and can be, for example, a waveform that varies at a certain period. As another example other than the triangular wave, the waveform of the AC component can be a sine wave, a rectangular wave, or the like. By controlling the waveform of the AC component, various target spectral waveforms can be generated.

[0324] 7.4 Effects / Advantages

[0325] The laser device 212 using the solid laser system 222 as the oscillator has the following advantages compared to the case of using an excimer laser as the oscillator.

[0326] [1] The solid laser system 222 is able to control the wavelength λ and the spectral linewidth Δλ at high speed and high precision by controlling the current value A of the DFB laser 250. That is, if the laser device 212 receives data of the target wavelength λtand the target spectral linewidth Δλt, the current value A of the DFB laser 250 is controlled immediately, and the oscillation wavelength and the spectral linewidth Δλ are controlled at high speed, and thus the wavelength λ and the spectral linewidth Δλ of the pulsed laser output from the laser device 212 are able to be changed at high speed and high precision for each pulse.

[0327] [2] Furthermore, by controlling the current value A of the DFB laser 250 to be chirped, various functional spectral waveforms different from the normal spectral waveform can be generated.

[0328] [3] Therefore, in the case of controlling the wavelength and the spectral linewidth calculated from the spectral waveform according to the moving cumulative value of the spectral waveform as the laser control parameter, it is preferable to have a laser device having an oscillator using a solid laser system 222 including a DFB laser 250 and an excimer amplifier 224.

[0329] 7.5 Others

[0330] As an embodiment of the solid laser device, it is not limited to Figure 31The example shown, for example, can also be a solid laser system including a DFB laser and an SOA with a wavelength of about 1547.2 nm, and the wavelength conversion system is a laser device that outputs 8th harmonic light of 193.4 nm. In addition, a system having a CW oscillation DFB laser and an SOA, in which the current value of the current flowing in the DFB laser is controlled and a pulse current flows in the SOA, can be used as another solid laser device, and the wavelength is pulse-amplified thereby.

[0331] In Figure 31 In the example, as the excimer amplifier, an example of a multi-pass amplifier is shown, but the embodiment is not limited thereto, and for example, an amplifier having an optical resonator such as a Fabry-Perot resonator or a ring resonator can also be used.

[0332] 8. Hardware configuration of various control units

[0333] The control device that functions as the laser control unit 20, the exposure control unit 40, the lithography control unit 110, the solid laser control unit 238, the semiconductor laser control unit 268, and the other control units can be realized by a combination of hardware and software of one or a plurality of computers. Software is synonymous with a program. A programmable controller is included in the concept of a computer. The computer can be configured to include a CPU (Central Processing Unit) and a storage device such as a memory. The CPU is an example of a processor.

[0334] The storage device is a non-transitory computer-readable medium as a tangible object, and for example, includes a memory as a main storage device and a memory as an auxiliary storage device. The computer-readable medium can be, for example, a semiconductor memory, a hard disk drive (HDD) device, or a solid state drive (SSD) device, or a plurality of combinations thereof. The program executed by the processor is stored in the computer-readable medium.

[0335] In addition, a part or all of the processing functions of the control device can also be realized using an integrated circuit represented by an FPGA (Field Programmable Gate Array) and an ASIC (Application Specific Integrated Circuit).

[0336] In addition, it is also possible to realize the functions of a plurality of control devices using one control device. Furthermore, in the present disclosure, the control devices can also be connected to each other via a communication network such as a local area network or the Internet. In a distributed computing environment, program units can also be stored in memory storage devices on both the local and remote sides.

[0337] 9. A method for manufacturing an electronic device

[0338] Figure 26 A configuration example of the exposure apparatus 14 is schematically shown. The exposure apparatus 14 includes an illumination optical system 44 and a projection optical system 50. The illumination optical system 44 illuminates a reticle pattern of a reticle 46 arranged on a reticle stage 48, which is not shown, with laser light incident from the laser device 12. The projection optical system 50 reduces and projects the laser light after passing through the reticle 46, so as to form an image on a workpiece, which is not shown, arranged on a workpiece stage WT. The workpiece can be a photosensitive substrate such as a semiconductor wafer coated with a resist. The workpiece stage WT can be a wafer stage 54.

[0339] The exposure apparatus 14 moves the reticle stage 48 and the workpiece stage WT in parallel in synchronization, thereby exposing the workpiece with the laser light reflecting the reticle pattern. After the reticle pattern is transferred on the semiconductor wafer by the above exposure process, a semiconductor device can be manufactured through a plurality of processes. The semiconductor device is an example of the "electronic device" in the present disclosure.

[0340] ​ The laser device 12 in the above embodiment can be a laser device 212 including a solid-state laser system 222 described in the above embodiment. ​

[0341] 10. Other

[0342] The above description is not a limitation but a simple example. Therefore, it is understood by those skilled in the art that modifications can be made to the embodiments of the present disclosure without departing from the scope of the claims. Furthermore, it is also understood by those skilled in the art that the embodiments of the present disclosure can be used in combination.

[0343] The terms used throughout the specification and claims should be interpreted as "non-limiting" terms unless explicitly stated otherwise. For example, the terms "comprise", "include", "have", "possess", and the like should be interpreted as "not excluding the presence of other structural elements not recited". In addition, the modifier "one" should be interpreted as "at least one" or "one or more". In addition, 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". Furthermore, it should be interpreted as including combinations of other elements and "A", "B", "C" in addition to them.​

Claims

1. An exposure system which irradiates a reticle with a pulsed laser to perform a scanning exposure on a semiconductor substrate, wherein, The exposure system has: a laser device that outputs the pulsed laser light; an illumination optical system that guides the pulsed laser light to the reticle; a reticle stage that moves the reticle; and a processor that controls the output of the pulsed laser light from the laser device and the movement of the reticle by the reticle stage, the reticle includes regions in which a plurality of patterns are mixedly arranged in a scan width direction orthogonal to a scan direction of the scan exposure, the processor instructs the laser device of a target wavelength of the pulsed laser light to output the pulsed laser light of a wavelength that minimizes a variance of optimal focus positions corresponding to the plurality of patterns respectively, in a case where the scan direction of the scan exposure is assumed to be a Y-axis direction and a Y-axis direction beam width of a scan beam of the pulsed laser light that scans the reticle toward a positive side of the Y-axis direction is assumed to be a By width, the processor obtains, from information of a reticle pattern of the reticle, enlarged regions in which boundaries of the plurality of patterns on a negative side of the Y-axis direction are changed toward the negative side of the Y-axis direction by a distance corresponding to the By width to enlarge the regions of the patterns respectively, the processor obtains, from a second file, a combination of the plurality of patterns within a scan field, and positions of the enlarged regions of the patterns respectively, a target wavelength of each pulse of the pulsed laser light that exposes the scan field, the second file including data obtained by associating the combination of the plurality of patterns and a wavelength of the pulsed laser light that minimizes a variance of the optimal focus positions corresponding to the plurality of patterns respectively.

2. The exposure system according to claim 1, wherein the processor changes the wavelength of the pulsed laser light, and calculates the optimal focus position of each of the plurality of patterns, the processor obtains, for the combination of the plurality of patterns, a wavelength that minimizes a variance of the optimal focus positions of the plurality of patterns respectively.

3. The exposure system according to claim 1, wherein the optimal focus position corresponding to each of the plurality of patterns is a position of optimal focus in which a value of a critical dimension in a focus curve that represents a relationship between a critical dimension and focus of each of the plurality of patterns becomes an extreme value.

4. The exposure system according to claim 1, wherein the processor executes a lithography simulation program including an electromagnetic field analysis function, and thereby calculates the optimal focus position corresponding to each of the plurality of patterns.

5. The exposure system according to claim 1, wherein the exposure system further has a projection optical system that projects an image of the reticle to the semiconductor substrate, the processor calculates the optimal focus position corresponding to each of the plurality of patterns using a plurality of data including a parameter of the illumination optical system, a parameter of the projection optical system, a parameter of a resist coated on the semiconductor substrate, a reticle pattern of the reticle, and a control parameter of the pulsed laser light, the processor calculates, for a combination of the plurality of patterns, a variance of the optimal focus positions corresponding to the plurality of patterns included in the combination, The processor calculates the wavelength of the pulsed laser that minimizes the variance of the optimal focus positions.

6. The exposure system according to claim 5, wherein The processor changes the wavelength as the control parameter of the pulsed laser, calculates the optimal focus positions corresponding to the plurality of patterns respectively, The processor calculates, for a combination of the plurality of patterns, the variance of the optimal focus positions corresponding to the plurality of patterns included in the combination respectively, The processor saves, in a first file, the wavelength of the pulsed laser that minimizes the variance of the optimal focus positions corresponding to the plurality of patterns respectively and the optimal focus position corresponding to the combination, in association with the wavelength.

7. The exposure system according to claim 6, wherein The processor calculates, for a combination of the plurality of patterns, the wavelength of the pulsed laser that minimizes the variance of the optimal focus positions corresponding to the plurality of patterns included in the combination respectively, from the data of the first file, The processor saves, in a second file, the combination of the plurality of patterns and the wavelength of the pulsed laser that minimizes the variance.

8. The exposure system according to claim 1, wherein The processor uses information including geometric dimensions defining a three-dimensional structure of a reticle pattern and physical property values of materials respectively constituting the plurality of patterns, for electromagnetic field analysis, thereby calculating the optimal focus positions corresponding to the plurality of patterns respectively.

9. The exposure system according to claim 1, wherein The exposure system further has a server that manages parameters used in the scan exposure, The server changes the wavelength of the pulsed laser, calculates the optimal focus positions corresponding to the plurality of patterns respectively, The server calculates, for a combination of the plurality of patterns, the wavelength of the pulsed laser that minimizes the variance of the optimal focus positions corresponding to the plurality of patterns included in the combination respectively.

10. The exposure system according to claim 1, wherein The processor uses the second file to calculate a target wavelength of the pulsed laser for each pulse in a region including the plurality of patterns.

11. The exposure system according to claim 1, wherein The processor controls the laser device according to a wavelength of a movement cumulative spectrum of the pulsed laser exposed in a scan field of the semiconductor substrate.

12. The exposure system according to claim 1, wherein The exposure system further has an inspection device that measures a critical dimension of an exposed semiconductor substrate on which the scan exposure is performed, The processor calculates, from a measurement result obtained using the inspection device and information of a reticle pattern of the reticle, the wavelength of the pulsed laser that minimizes the variance of the optimal focus positions corresponding to the plurality of patterns respectively.

13. The exposure system according to claim 12, wherein The processor associates a pattern exposed to the exposed semiconductor substrate, a wavelength of the pulsed laser exposed, and a value of a critical dimension corresponding to the optimal focus position, The processor calculates a variance value of each of the optimal focus positions with respect to a combination of a plurality of the patterns and the wavelength, The processor saves data of the optimal focus positions corresponding to the patterns and the wavelength in a first file, The processor calculates a variance value of each of the optimal focus positions with respect to a combination of a plurality of the patterns and the wavelength, The processor saves data of the optimal focus positions corresponding to the patterns and the wavelength in a first file, The processor calculates a variance value of each of the optimal focus positions with respect to a combination of a plurality of the patterns and the wavelength, The processor saves data of the optimal focus positions corresponding to the patterns and the wavelength in a first file, 14. The exposure system according to claim 1, wherein The laser device is an excimer laser device including an oscillator and an amplifier that amplifies pulsed laser light output from the oscillator, The oscillator has a narrowbanding module.

15. The exposure system according to claim 1, wherein The laser device is an excimer laser device including an oscillator and an amplifier that amplifies pulsed laser light output from the oscillator, The oscillator is a solid laser system using a distributed feedback type semiconductor laser.

16. A method of manufacturing electronic devices, wherein The method of manufacturing electronic devices includes a step of performing a scan exposure on a photosensitive substrate using an exposure system that irradiates pulsed laser light on a reticle to manufacture electronic devices, The exposure system has: a laser device that outputs the pulsed laser light; the reticle; an illumination optical system that guides the pulsed laser light to the reticle; a reticle stage that moves the reticle; and a processor that controls the output of the pulsed laser light from the laser device and the movement of the reticle by the reticle stage, The reticle includes regions in which a plurality of patterns are mixedly arranged in a scan width direction orthogonal to a scan direction of the scan exposure, The processor instructs the laser device of a target wavelength of the pulsed laser light to output the pulsed laser light of a wavelength that minimizes a variance of optimal focus positions corresponding to the plurality of patterns respectively, In a case where the scan direction of the scan exposure is assumed to be a Y-axis direction and a Y-axis direction beam width of a scan beam of the pulsed laser light that scans the reticle toward a positive side of the Y-axis direction is assumed to be a By width, The processor calculates, based on information of a reticle pattern of the reticle, an enlarged region in which regions of the plurality of patterns are enlarged by changing boundaries of the Y-axis direction negative side of the patterns to the Y-axis direction negative side by a distance corresponding to the By width, ​ The processor calculates a target wavelength of each pulse of the pulsed laser for exposing the scanning field, based on the second file, the combination of the plurality of patterns in the scanning field, and the positions of the enlarged areas of the respective patterns, the second file containing data obtained by associating the combination of the plurality of patterns with the wavelength of the pulsed laser that minimizes the variance of the optimal focus positions corresponding to the plurality of patterns, respectively. The processor calculates a target wavelength of each pulse of the pulsed laser for exposing the scanning field, based on the second file, the combination of the plurality of patterns in the scanning field, and the positions of the enlarged areas of the respective patterns, the second file containing data obtained by associating the combination of the plurality of patterns with the wavelength of the pulsed laser that minimizes the variance of the optimal focus positions corresponding to the plurality of patterns, respectively.

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