Exposure method, exposure apparatus, and method of manufacturing article

Abstract

To provide an exposure method in which exposure processing can be performed in a state of reduced influence of aberration.SOLUTION: An exposure method has: a prediction process of predicting changes of optical characteristics of a projection optical system in an exposure process of performing exposure treatment to substrates via the projection optical system; an adjustment process of irradiating the projection optical system with light on the basis of a prediction result of the prediction process before the exposure process to adjust the optical characteristics; and an exposure process to be executed after the adjustment process. In the adjustment process, the optical characteristics when starting the exposure process are adjusted to a positive value or a negative value on the basis of changes of the optical characteristics predicted in the prediction process such that the optical characteristics become within a predetermined range even if the optical characteristics are not adjusted in the exposure process.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an exposure method, an exposure apparatus, and a method for manufacturing an article. [Background technology]

[0002] In the manufacturing process of semiconductor devices, liquid crystal display devices, etc., an exposure apparatus is used in which an original is illuminated by an illumination optical system, and the pattern of the original is projected onto a substrate via a projection optical system to expose the substrate. When the projection optical system absorbs the exposure light and generates heat, aberration occurs, and this aberration affects the results of the exposure process.

[0003] Patent Document 1 discloses a method for predicting aberration due to an exposure process and determining whether or not to execute the next exposure process based on the prediction result. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-103343 A Summary of the Invention [Problem to be solved by the invention]

[0005] From the viewpoint of productivity, it is preferable to correct aberrations when they occur and quickly perform the next exposure process. In addition, since aberrations change even while exposure processes are being performed on one lot, if the aberrations become large during the course of a lot, the resolution performance decreases, and the desired quality may not be met.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an exposure method capable of performing exposure processing in a state in which the effects of aberration are reduced. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, an exposure method as one aspect of the present invention includes a prediction step of predicting changes in optical characteristics of a projection optical system in an exposure step of performing exposure processing of a substrate via a projection optical system, an adjustment step of irradiating light to the projection optical system and adjusting the optical characteristics based on a prediction result of the prediction step prior to the exposure step, and the exposure step is performed after the adjustment step, and is characterized in that the adjustment step adjusts the optical characteristics to positive or negative values ​​at the start of the exposure step based on the change in the optical characteristics predicted in the prediction step so that the optical characteristics are within a predetermined range without the need for adjustment of the optical characteristics in the exposure step.

[0008] Further objects or other aspects of the present invention will become apparent from the embodiments described below with reference to the drawings. Effect of the Invention

[0009] According to the present invention, it is possible to carry out an exposure process while reducing the influence of aberration. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus in a first embodiment. [Diagram 2] 13 is a diagram showing the relationship between focus and light amount when the substrate stage is driven in the Z direction. FIG. [Diagram 3] FIG. 2 is a schematic diagram of a line and space of a reticle side mark; [Figure 4] 6 is a flowchart for storing an aberration saturation amount used in a prediction equation for predicting astigmatism in the first embodiment. [Diagram 5] 4 shows a result of aberration prediction in the first embodiment. [Figure 6] 4 is an example of a light intensity distribution on a pupil plane of an illumination optical system used for dummy illumination in the first embodiment. [Figure 7] 5 is a flowchart for performing dummy irradiation for correcting astigmatism in the first embodiment. [Figure 8] 4 is an example of adjustment of astigmatism in the first embodiment. [Figure 9] 10 is a flowchart of a method for manufacturing an article in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment does not limit the invention according to the claims. Although the embodiment describes a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0012] In addition, in this specification and drawings, directions are basically indicated by an XYZ coordinate system in which the vertical direction is the Z axis, the horizontal plane perpendicular to the vertical direction is the XY plane, and each axis is orthogonal to each other. However, if an XYZ coordinate system is described in each drawing, that coordinate system takes precedence.

[0013] A specific configuration will be described below for each embodiment.

[0014] First Embodiment FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus 100 in this embodiment. Light emitted from a light source 101 enters an illumination optical system 102, and a diffractive optical element 103 forms a light intensity distribution (hereinafter also referred to as an effective light source distribution) on the pupil plane of the illumination optical system 102, and the light is irradiated onto a reticle 104 surface. The reticle 104 is an original plate on which a pattern (e.g., a circuit pattern) to be transferred is formed of chrome on the surface of, for example, quartz glass. The light irradiated onto the pattern drawn on the reticle 104 is diffracted by the reticle 104 and enters a projection optical system 107, and the amount of light is adjusted by an aperture stop 108 arranged in the projection optical system 107. The light reaches a substrate 110, and the pattern on the reticle 104 is reduced and projected. Here, the substrate 110 is, for example, single crystal silicon, and a photosensitive material (resist) is applied onto the surface. A control unit 120 controls each unit in the exposure apparatus 100. A storage unit 130 stores information obtained from the control unit 120.

[0015] The reticle 104 is held by a reticle stage 106, which is driven to scan in the +Y direction. The substrate stage 111 holding the substrate 110 is driven to scan in the -Y direction, and when exposure of the corresponding shot area is completed, it is driven to step in order to expose the next shot area.

[0016] A reticle reference plate 105 separate from the reticle 104 is configured on the reticle stage 106, and reticle-side marks for measuring an aerial image are provided on the reticle reference plate 105. The reticle-side marks are a periodically arranged line-and-space pattern. Furthermore, a detection plate 112 is disposed on the substrate stage 111, and a substrate-side mark (not shown) for measuring an aerial image is provided on the detection plate 112. The substrate-side mark is a line-and-space pattern arranged with the same period as the reticle-side mark. Furthermore, a photodetector 115 is disposed below the detection plate 112.

[0017] The light-shielding portions of the line-and-space patterns provided on the reticle-side mark and the substrate-side mark are made of, for example, chrome, and the light-transmitting portions are made of glass. The reticle stage 106 is driven in the Y direction so that the light emitted from the light source 101 is irradiated onto the reticle-side mark on the reticle reference plate 105 via the illumination optical system 102. The light that has passed through the reticle-side mark on the reticle reference plate 105 reaches the substrate-side mark on the detection plate 112 via the projection optical system 107. The light that has reached the reticle-side mark passes through the substrate-side mark on the detection plate 112 and reaches the photodetector 115.

[0018] Next, aerial image measurement, which is a measurement method for measuring astigmatism (optical characteristics), will be described. Light emitted from the light source 101 irradiates the reticle reference plate 105 via the illumination optical system 102, and the reticle-side mark is reduced and projected onto the substrate-side mark via the projection optical system 107. When the substrate stage 111 is driven in the Z direction, which is the optical axis direction, in the reduced and projected state, the reduced and projected image of the reticle-side mark overlaps with the substrate-side mark at the best focus position of the projection optical system 107. Then, the amount of light received by the photodetector 115 becomes maximum. When the substrate-side mark on the detection plate 112 moves away from the best focus position, the contrast of the image of the reduced and projected reticle-side mark decreases and becomes blurred, so the amount of light received by the photodetector 115 decreases.

[0019] 2 is a diagram showing the relationship between focus and light amount when the substrate stage 111 is driven in the Z direction. The example in FIG. 2 shows an example in which the substrate stage 111 is driven in the Z direction on either side of the best focus position with the reticle-side mark projected on the substrate-side mark in a reduced scale, with the horizontal axis showing focus and the vertical axis showing the light amount detected by the photodetector 115. The relationship between focus and light amount shown here is a curved shape having a convex shape on the upper side, and the peak position of this curved shape is the best focus position. Note that in this embodiment, an example has been shown in which the light that has passed through the reticle-side mark and the substrate-side mark is detected by the photodetector 115, and the best focus position is obtained from the result, but the method of obtaining the best focus position is not limited to this example.

[0020] FIG. 3 is a schematic diagram of the lines and spaces of the reticle-side mark 113. The substrate-side mark has a similar configuration. The reticle-side mark 113 and the substrate-side mark are provided with lines and spaces in the X and Y directions, respectively, for measuring astigmatism. In a state in which the lines and spaces in the X and Y directions of the reticle-side mark 113 are reduced and projected onto the substrate-side mark, the substrate stage 111 is driven in the Z direction in an area sandwiching (including) the best focus positions in both the X and Y directions. This makes it possible to obtain the relationship between focus and light amount as shown in FIG. 2 for each of the lines and spaces in the X and Y directions. Based on the obtained relationship between focus and light amount for the lines and spaces in the X and Y directions, the best focus positions in the X and Y directions are obtained from the position (peak position) where the light amount is maximum. Then, the astigmatism can be obtained by obtaining the difference between the obtained best focus position in the X direction and the best focus position in the Y direction.

[0021] 4 is a flowchart for storing the aberration saturation amount P (first coefficient) used in the prediction equation (prediction model) for predicting astigmatism in this embodiment. In this embodiment, first information is obtained in advance, which is information including the aberration saturation amount P (first coefficient) for predicting a change in optical characteristics in an exposure process in which this exposure process is performed.

[0022] First, astigmatism measurement is performed using an effective light source distribution for exposure processing (S110), and exposure processing is performed on the Nth substrate that has not been exposed among the substrates to be pre-measured (S120). Here, the substrate to be pre-measured is a substrate used to obtain the aberration saturation amount P, for example, a substrate included in one lot. The aberration saturation amount P is a value specific to the exposure processing conditions. Next, the control unit 120 determines whether or not all the substrates to be pre-measured have been exposed (S130), and if all the substrates to be pre-measured have not been exposed, the process returns to step S110. If all the substrates to be pre-measured have been exposed, astigmatism measurement is performed using an effective light source distribution for exposure processing (S140), and the control unit 120 obtains the aberration saturation amount P to be used in the prediction formula (S150). Then, the storage unit 130 associates the exposure processing conditions with the aberration saturation amount P and stores them (S160), and the process ends. In this embodiment, an example has been shown in which the optical characteristics (astigmatism) of all substrates to be pre-measured (e.g., 25 substrates included in one lot) are measured. However, if the amount of acquired information is sufficient, it is not necessary to measure the optical characteristics (astigmatism) of all substrates to be pre-measured. For example, if it is determined in step S130 that all substrates to be pre-measured have been exposed, the process may proceed to step S150 without performing step S140.

[0023] The aberration saturation amount P used in the prediction formula for predicting the astigmatism obtained in step S150 is obtained by fitting the result of the astigmatism measurement to the prediction formula expressed by formula (1), formula (2), and formula (3). Based on the obtained aberration saturation amount P, the prediction formula of formula (1), formula (2), and formula (3), and the measurement result of the astigmatism before the exposure process (second information), it is possible to predict the amount of astigmatism generated when the exposure process is actually performed.

[0024]

number

[0025] Here, Φ is the predicted amount of modeled astigmatism, and the subscript N indicates the timing at which the astigmatism is measured. In this embodiment, three time constants (K) are used. The subscript m indicates the model number, with m=1 being the long-term time constant model, m=2 being the medium-term time constant model, and m=3 being the short-term time constant model. In this embodiment, three time constant models are used to obtain three aberration saturation amounts P, but the time constant model may be two or more. α indicates an exposure load, and its value differs depending on the exposure conditions. The exposure load α can be obtained from the reticle transmittance R, the exposure dose D, the shot size A, the number of shots Num between astigmatism measurements, and the time T between astigmatism measurements, as shown in Equation (3). The exposure load α may also be calculated using other parameters such as resist reflectance.

[0026] FIG. 5 shows the aberration prediction results in this embodiment, with the horizontal axis representing time and the vertical axis representing the amount of astigmatism. The white dots are the measured values ​​of astigmatism measured in steps S110 and S140, and the solid line is the result of predicting the aberration generated by the prediction formula. The control unit 120 measures the astigmatism in steps S110 and S140 under exposure processing conditions that may be implemented in advance, and obtains the aberration saturation amount P from the measurement results and formulas (1), (2), and (3). The storage unit 130 then associates the aberration saturation amount P obtained by the control unit 120 with the exposure processing conditions and stores them. When performing exposure processing under the same conditions as the exposure processing conditions stored in the storage unit 130, the control unit 120 predicts the amount of aberration generated during exposure processing based on the information stored in the storage unit 130. Specifically, the amount of aberration that will occur during the exposure process is predicted using the aberration saturation amount P, which is linked to the exposure process conditions and stored in the memory unit 130, equations (1), (2), and (3), and the measurement results of the astigmatism measured before the exposure process.

[0027] Next, dummy illumination for correcting astigmatism will be described. Fig. 6 shows an example of a light intensity distribution (effective light source distribution) on the pupil plane of the illumination optical system 102 used for dummy illumination in this embodiment. Light emitted from the light source 101 is formed into an effective light source distribution as shown in Fig. 6(a) or 6(b) by the diffractive optical element 103 in the illumination optical system 102. The dotted line in Fig. 6 represents σ=1, and the area shown in white has light intensity.

[0028] The light of the formed effective light source distribution is made to enter the projection optical system 107 through the illumination optical system 102 without passing through the reticle 104. At this time, by narrowing the aperture stop 108 formed near the pupil in the projection optical system 107, the light entering the projection optical system 107 illuminates the aperture stop 108, and the light does not reach the substrate 110. When the light entering the projection optical system 107 enters the lens group constituting the projection optical system 107, the lens is heated due to absorption by the glass material of the lens and the film absorption by the anti-reflection film, and the refractive index of the lens changes, and wavefront aberration occurs. For example, when an effective light source distribution as shown in FIG. 6(a) is formed by the diffractive optical element 103 and made to enter the projection optical system 107, the wavefront aberration of the projection optical system 107 generated is a distribution according to the effective light source distribution. In other words, it is possible to control the sign of astigmatism by switching the diffractive optical element 103 to select the effective light source distribution so as to obtain a desired sign of astigmatism, and performing dummy irradiation. In addition, the desired amount of astigmatism can be obtained by adjusting the time of dummy irradiation. In the present embodiment, an example has been shown in which dummy irradiation is performed using the 2θ component of the wavefront aberration, but the 3θ component or 4θ component may also be used, and there is no particular limitation.

[0029] Here, a method for determining the time for performing dummy irradiation will be described. First, information on the relationship between the time for which dummy irradiation is performed on the projection optical system 107 and the amount of change in astigmatism of the projection optical system 107 is acquired in advance. Next, a proportionality coefficient (Coef) indicating the amount of change in astigmatism of the projection optical system 107 per unit time is obtained based on the acquired information. The proportionality coefficient (Coef) is a second coefficient. Then, the time for performing dummy irradiation (irradiation time) is determined by equation (4). Note that T is the time for performing dummy irradiation, and AS is the amount of astigmatism changed when adjusting the astigmatism of the projection optical system 107 to a desired astigmatism. T=Coef×AS...Formula (4)

[0030] In this embodiment, the amount of change in astigmatism is adjusted by adjusting the time for which dummy irradiation is performed. However, the amount of dummy irradiation may be used instead of the time for which dummy irradiation is performed.

[0031] FIG. 7 is a flow chart when performing dummy irradiation for correcting astigmatism in this embodiment. First, the control unit 120 judges whether or not to perform astigmatism measurement (S210). Here, the timing of performing astigmatism measurement may be freely set by the user, and may be set to perform at the beginning of a lot, or may be set to perform before exposing a specific reticle. If astigmatism measurement is not performed, exposure processing is performed (S270) and the process ends. If astigmatism measurement is performed, astigmatism is measured using an effective light source distribution for exposure processing (S220). Then, the control unit 120 judges whether or not the astigmatism will be outside the allowable range (outside the predetermined range) during processing of the target substrate based on the result of measuring the astigmatism and the aberration saturation amount P associated with the exposure processing conditions stored in the storage unit 130 (S230, prediction process). The judgment in step S230 is performed using formulas (1), (2), and (3). Here, the storage unit 130 stores a plurality of exposure processing conditions associated with the first information including the aberration saturation amount P (first coefficient). Then, the control unit 120 selects, from among the exposure processing conditions stored in the storage unit 130, the exposure processing condition that is the same as the exposure processing condition when the astigmatism was measured, and predicts a change in the astigmatism using the aberration saturation amount P associated with the selected exposure processing condition.

[0032] The target substrate refers to a substrate to be processed before the next astigmatism measurement is performed, and for example, if the user sets the astigmatism measurement to be performed at the beginning of a lot, it refers to all substrates in the lot. The allowable range (predetermined range) is set in advance by the user for each exposure processing condition based on the influence of aberration and the accuracy required for the exposure processing.

[0033] If the astigmatism does not fall outside the allowable range during processing of the target substrate, the adjustment step is not performed, and exposure processing is performed (S270, exposure step), and the process ends. If the astigmatism falls outside the allowable range during processing of the target substrate, the control unit 120 determines whether the astigmatism changes in the positive direction during processing of the target substrate from the prediction formula obtained from formulas (1), (2), and (3) (S240). If the astigmatism changes in the positive direction, the reticle 104 is withdrawn, and dummy irradiation is performed so that the astigmatism at the start of the exposure processing is on the negative side of the allowable range (S250, adjustment step). If the astigmatism changes in the negative direction, the reticle 104 is withdrawn, and dummy irradiation is performed so that the astigmatism at the start of the exposure processing is on the positive side of the allowable range (S260, adjustment step). The effective light source distribution used in the dummy irradiation in steps S250 and S260 is switched so that the astigmatism has a desired sign by the dummy irradiation. The amount of change in the astigmatism (optical characteristics) changed by the dummy irradiation in steps S250 and S260 is determined so that the astigmatism does not fall outside the allowable range during processing of the target substrate (for example, one lot). Then, the optical characteristics at the start of the exposure process are adjusted according to the amount of change in the determined optical characteristics. That is, the astigmatism is adjusted so that the astigmatism falls within the allowable range (predetermined range) without adjusting the astigmatism in the exposure process of the target substrate. Specifically, the optical characteristics (astigmatism) at the start of the exposure process are adjusted to a positive or negative value. This is synonymous with adjusting the optical characteristics to a value deviated from the value of the optimal optical characteristics. Also, instead of adjusting the optical characteristics themselves, a form may be adopted in which the conditions under which the optical characteristics are optimal (for example, the position of the substrate stage 111 under which the optical characteristics are optimal) are adjusted to conditions under which the optical characteristics are not optimal.

[0034] Also, preferably, adjustment is performed so that the astigmatism value during exposure of the target substrates (for example, one lot) is on average close to 0 before the astigmatism falls outside the allowable range during processing of the target substrates. Then, after the adjustment processes of steps S250 and S260, the reticle 104 that had been retracted is placed in a position where exposure processing can be performed, and the diffractive optical element 103 is switched so as to obtain an effective light source distribution for exposure processing, and exposure processing is performed (S270, exposure process), and the process ends.

[0035] In this embodiment, whether or not the astigmatism falls outside the allowable range during processing of the target substrate is judged, and whether or not dummy irradiation is required is determined. However, a threshold value may be set instead of the allowable range (predetermined range), and whether or not dummy irradiation is required may be determined by comparing the astigmatism measurement result with the threshold value.

[0036] FIG. 8 is an example of astigmatism adjustment in this embodiment. In the example of FIG. 8, 25 substrates included in one lot are the target substrates, and the allowable range of astigmatism is set to −30 (nm) to +40 (nm) as indicated by the upper and lower limits of the dashed and dotted lines. The change in astigmatism when the astigmatism is not adjusted is indicated by the dotted line. When the astigmatism is not adjusted, the astigmatism is outside the allowable range when the 13th substrate is processed. In this case, the exposure processing results of the 13th and subsequent substrates are significantly affected by the astigmatism. In this embodiment, the change in astigmatism (optical characteristics) when the target substrate is processed is obtained based on the astigmatism measurement result, the previously obtained aberration saturation amount P, and formulas (1), (2), and (3), and the amount of astigmatism to be adjusted is obtained. Specifically, the direction of change (tilt direction) of astigmatism over time and the amount of change (maximum change) of aberration during processing of a target substrate (e.g., one lot) are obtained, and the amount of astigmatism to be adjusted is obtained. Here, the change in astigmatism (optical characteristic) in this embodiment is synonymous with the change amount (tilt) of astigmatism per unit time, which is composed of the elements of the maximum change amount of astigmatism expected to change during processing of a target substrate (substrate included in one lot) and the tilt direction of astigmatism. Also, in this embodiment, an example of adjusting astigmatism based on the direction of change (tilt direction) of astigmatism over time and the amount of change (maximum change) of aberration during processing of a target substrate (e.g., one lot) has been shown. However, astigmatism may be adjusted based only on the maximum change amount of astigmatism. In other words, the element indicating the change in astigmatism (optical characteristic) in this embodiment includes one or both of the change amount of optical characteristic per unit time and the maximum change amount of optical characteristic during exposure processing.

[0037] For example, in FIG. 8, it can be predicted that the inclination direction of the change in astigmatism is the + direction, and the aberration change amount (maximum change amount) during processing of the target substrate (for example, one lot) is +60 (nm) from the measurement result of the astigmatism, the aberration saturation amount P obtained in advance, and the formula (1), formula (2), and formula (3). Therefore, even if the astigmatism changes by +60 (nm), the control unit 120 adjusts the astigmatism by dummy irradiation so that it does not fall outside the allowable range. In the example of FIG. 8, the astigmatism is adjusted in a direction (- direction) different from the inclination direction (+ direction) of the astigmatism, and the adjustment amount is adjusted so that the astigmatism at the start of exposure is -30 (nm) so that the astigmatism is within the allowable range even without adjusting the astigmatism in the exposure process. In other words, in the adjustment process, the optical characteristic (astigmatism) at the start of the exposure process is adjusted to a sign side different from the sign of the inclination in the change in the optical characteristic predicted in the prediction process. This adjustment brings the astigmatism within the allowable range during processing of the target substrate, and reduces the effect of the aberration on the results of the exposure process. Note that, although the example in which the astigmatism is adjusted to -30 (nm) in accordance with the lower limit of the allowable range has been shown in this embodiment, it is sufficient to adjust the astigmatism in the exposure process so that it is within the allowable range, so in the example of FIG. 8, it may be adjusted to -20 (nm).

[0038] In addition, it is preferable that the astigmatism during the exposure process (exposure step) remains close to 0 within the allowable range. Therefore, the adjustment of the astigmatism is preferably performed so that the average value of the astigmatism during the exposure process is reduced. For example, in this embodiment, the average value of the astigmatism in the exposure process can be reduced by adjusting the astigmatism to -25 (nm). Note that, although an example of adjusting the astigmatism has been described in this embodiment, it is sufficient that the optical characteristic is changed by irradiating the projection optical system with light, and the optical characteristic to be adjusted is not limited to astigmatism. For example, the optical characteristic to be adjusted in this embodiment may be spherical aberration, coma aberration, curvature of field, distortion, etc.

[0039] According to this embodiment, the amount of aberration generated during exposure processing can be predicted by applying the previously acquired aberration saturation amount P and the measurement result of astigmatism to a prediction formula, and the astigmatism can be adjusted by performing dummy irradiation based on this prediction result. This allows exposure processing to be performed with astigmatism within the allowable range set by the user without adjusting the astigmatism during the exposure processing of the target substrate (for example, one lot), and the influence of astigmatism on the exposure processing result can be reduced.

[0040] <Second embodiment> The present embodiment is characterized in that an article is manufactured using the exposure apparatus (exposure method) described in the first embodiment.

[0041] 9 is a flowchart of a method for manufacturing an article in this embodiment. An exposure process (S310) is performed in which the optical characteristics (astigmatism) are adjusted using the exposure apparatus (exposure method) described in the first embodiment, and a substrate is exposed to light. Then, a development process (S320) is performed in which a photosensitive material on the substrate on which a pattern has been formed by exposure in the exposure process is developed, and a manufacturing process (S330) is performed in which an article is manufactured from the substrate developed in the development process.

[0042] Products manufactured by this manufacturing method include, for example, semiconductor IC elements, liquid crystal display elements, color filters, MEMS, and the like.

[0043] In the exposure process, for example, a substrate (silicon substrate, glass plate, etc.) coated with a photosensitive material is exposed to light by an exposure apparatus (lithography apparatus) to form a pattern on the substrate.

[0044] The manufacturing process includes, for example, etching the substrate developed in the developing process, resist peeling, dicing, bonding, and packaging. According to this manufacturing method, it is possible to manufacture products of higher quality than before.

[0045] The disclosure of the present specification includes the following exposure method, exposure apparatus, and method for manufacturing an article.

[0046] [Item 1] a prediction step of predicting a change in an optical characteristic of the projection optical system in an exposure step of performing an exposure process of a substrate through the projection optical system; an adjustment step of adjusting the optical characteristics of the projection optical system by irradiating the projection optical system with light based on the prediction result of the prediction step, prior to the exposure step; The exposure step is carried out after the adjustment step, the adjusting step includes adjusting the optical characteristic at the start of the exposure step to a positive or negative value based on the change in the optical characteristic predicted in the predicting step so that the optical characteristic falls within a predetermined range without adjustment of the optical characteristic in the exposure step; An exposure method comprising the steps of:

[0047] [Item 2] 2. The exposure method according to item 1, characterized in that the prediction of the change in the optical characteristics in the prediction step is performed based on first information which is information for predicting the change in the optical characteristics in the exposure step and second information which is information obtained by measuring the optical characteristics before the exposure step.

[0048] [Item 3] 3. The exposure method according to any one of items 1 to 2, wherein the element indicating the change in the optical characteristic includes one or both of an amount of change in the optical characteristic per unit time and a maximum amount of change in the optical characteristic during the exposure process.

[0049] [Item 4] 4. The exposure method according to any one of items 1 to 3, wherein in the adjusting step, the optical characteristics are adjusted so that an average value of the optical characteristics during the exposure process becomes small.

[0050] [Item 5] 5. The exposure method according to any one of items 1 to 4, wherein the predetermined range is set for each condition of the exposure process.

[0051] [Item 6] 6. The exposure method according to any one of items 1 to 5, wherein in the adjusting step, the optical characteristics at the start of the exposure step are adjusted to a side of a different sign from the sign of a slope of the change in the optical characteristics predicted in the predicting step.

[0052] [Item 7] 7. The exposure method according to any one of items 1 to 6, wherein the optical characteristic is astigmatism in the projection optical system.

[0053] [Item 8] 8. The exposure method according to any one of items 2 to 7, wherein the first information, which is information for predicting a change in optical characteristics in the exposure step, includes information on a first coefficient included in a prediction formula used in the prediction step.

[0054] [Item 9] 9. The exposure method according to item 8, wherein the first coefficient is a value indicating an amount of aberration saturation.

[0055] [Item 10] 10. The exposure method according to any one of items 1 to 9, wherein in the adjustment step, the optical characteristic is adjusted by irradiating the light for a time period determined based on a second coefficient indicating an amount of change in the optical characteristic per unit time.

[0056] [Item 11] 11. The exposure method according to any one of items 1 to 10, wherein the light irradiation in the adjustment step illuminates the projection optical system but does not illuminate the substrate.

[0057] [Item 12] 12. The exposure method according to any one of items 1 to 11, wherein the adjustment step is performed when an original on which a pattern is formed is in a position where it is not illuminated by the light.

[0058] [Item 13] 13. The exposure method according to any one of items 1 to 12, wherein the adjustment step is not performed if the prediction result of the prediction step indicates that the optical characteristics are within the predetermined range.

[0059] [Item 14] The exposure method according to any one of items 2 to 13, characterized in that first information, which is information for predicting a change in optical characteristics in the exposure step, is linked to conditions of the exposure processing and stored, and when the exposure processing is performed under conditions identical to the conditions, the first information is used to predict the optical characteristics.

[0060] [Item 15] 15. The exposure method according to any one of items 1 to 14, wherein in the adjusting step, the light intensity distribution on a pupil plane of an illumination optical system when irradiating the light is switched according to the prediction result in the predicting step.

[0061] [Item 16] a projection optical system that projects light; a control unit that controls the projection optical system to adjust optical characteristics when performing exposure processing on a substrate through the projection optical system by irradiating the projection optical system with light, the control unit predicts a change in the optical characteristics of the projection optical system, and based on a prediction result, controls to adjust the optical characteristics to a positive or negative value when the exposure process is started so that the optical characteristics are within a predetermined range without adjustment of the optical characteristics in the exposure process; An exposure apparatus comprising:

[0062] [Item 17] An exposure step of adjusting optical characteristics by using the exposure method according to any one of items 1 to 15 and exposing a substrate; a developing step of developing the photosensitive material on which the pattern is formed by the exposure step; a manufacturing process for manufacturing an article from the substrate developed in the developing process; A method for producing an article, comprising the steps of:

[0063] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

Claims

1. a prediction step of predicting a change in the optical characteristics of the projection optical system during an exposure step of performing exposure processing on a plurality of substrates through the projection optical system; an adjusting step of adjusting the optical characteristics based on the prediction result of the prediction step, before the exposure step; the exposure step being carried out after the adjustment step, In the adjusting step, the optical characteristics at the start of the exposure step are adjusted in a direction different from a direction in which the optical characteristics change, based on the change in the optical characteristics predicted in the predicting step; An exposure method characterized by:

2. The exposure method described in Claim 1, characterized in that the adjustment of the optical characteristics in the adjustment process is performed by irradiating light onto the projection optical system.

3. 2. The exposure method according to claim 1, wherein the prediction of the change in the optical characteristics in the prediction step is performed based on first information, which is information for predicting the change in the optical characteristics in the exposure step, and second information, which is information obtained by measuring the optical characteristics before the exposure step.

4. 2. The exposure method according to claim 1, wherein the element indicating the change in the optical characteristic includes one or both of the amount of change in the optical characteristic per unit time and the maximum amount of change in the optical characteristic during the exposure process.

5. 2. The exposure method according to claim 1, wherein in the adjusting step, the optical characteristics are adjusted so that an average value of the optical characteristics during the exposure process becomes a value close to zero.

6. 2. The exposure method according to claim 1, wherein in the adjustment step, the optical characteristics at the start of the exposure step are adjusted to a side of a sign different from the sign of the slope of the change in the optical characteristics predicted in the prediction step.

7. 2. An exposure method according to claim 1, wherein the optical characteristic is astigmatism in the projection optical system.

8. 4. The exposure method according to claim 3, wherein the first information includes information on a first coefficient included in a prediction formula used in the prediction step.

9. 9. An exposure method according to claim 8, wherein the first coefficient is a value indicating an amount of aberration saturation.

10. 3. The exposure method according to claim 2, wherein in the adjustment step, the optical characteristics are adjusted by irradiating the light for a time period determined based on a second coefficient indicating the amount of change in the optical characteristics per unit time.

11. 3. The exposure method according to claim 2, wherein the light irradiation in the adjustment step illuminates the projection optical system but does not illuminate the substrate.

12. 3. An exposure method according to claim 2, wherein the adjusting step is performed when the original on which the pattern is formed is in a position where it is not illuminated by the light.

13. The exposure method according to claim 3, wherein the first information is stored in association with the conditions of the exposure process, and when the exposure process is performed under the same conditions as the conditions, the first information is used to predict the optical characteristics.

14. 3. The exposure method according to claim 2, wherein in the adjusting step, a light intensity distribution on a pupil plane of an illumination optical system when irradiating the light is changed in accordance with the result of the prediction in the predicting step.

15. The exposure method according to claim 1, characterized in that the adjustment of the optical characteristics in the adjustment process adjusts the value of the optical characteristics to be positive or negative.

16. A prediction step of predicting changes in optical characteristics of a projection optical system during an exposure step of performing exposure processing on a plurality of substrates through the projection optical system; an adjusting step of adjusting the optical characteristics based on the prediction result of the prediction step, before the exposure step; the exposure step being carried out after the adjustment step, In the adjusting step, the optical characteristics are adjusted based on the change in the optical characteristics predicted in the predicting step so that the optical characteristics are within a predetermined range when the exposure step is started, without the need for adjustment of the optical characteristics. An exposure method characterized by:

17. The exposure method according to claim 16, wherein the predetermined range is set for each condition of the exposure process.

18. The exposure method according to claim 16, wherein the adjustment step is not performed if the prediction result of the prediction step indicates that the optical characteristics are within the specified range.

19. a projection optical system that projects light; a control unit that controls the projection optical system to adjust optical characteristics before performing exposure processing on a plurality of substrates through the projection optical system, the control unit predicts a change in the optical characteristic, and controls the optical characteristic at the start of the exposure process to be adjusted in a direction different from a direction in which the optical characteristic will change based on a prediction result; An exposure apparatus characterized by:

20. an exposure step of adjusting optical characteristics using the exposure method according to any one of claims 1 to 18 and exposing a substrate; a developing step of developing the photosensitive material on which the pattern has been formed by exposure in the exposure step; a manufacturing process for manufacturing an article from the substrate developed in the developing process; A method for manufacturing an article, comprising:

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