Determination method, program, exposure apparatus, and method for producing article

Abstract

To provide a technique for advantageous for increasing a diversity of products by an exposure apparatus.SOLUTION: Provided is a determination method of determining an exposure parameter value for performing a multiple focus exposure of exposing a photoresist layer on a substrate by changing a distance between a substrate and a focal point of a projection optical system to a plurality of respective distances by an exposure apparatus for transferring a pattern of an original plate to the substrate. The determination method includes: an acquisition process of acquiring a relation between an exposure parameter value set of a set of respective exposure parameter values of a plurality of distances and a resist profile exhibiting a cross sectional shape of a photoresist layer when performing multiple focus exposure according to an exposure parameter set and developing; and a determination process of determining an objective exposure parameter set for acquiring an objective resist profile based on an acquired relation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a determination method, a program, an exposure apparatus, and an article manufacturing method.

Background Art

[0002] In a lithography process, which is one of the manufacturing processes for semiconductor devices and the like, an exposure apparatus that transfers the pattern of a master onto a photoresist layer on a substrate by exposing the photoresist layer on the substrate through a projection optical system can be used. With the diversification of products manufactured by recent exposure apparatuses, exposure apparatuses have come to be required to handle various processes. For example, Patent Document 1 describes performing defocused exposure by shifting the relative distance between the lens of a stepper and the substrate from the best focus position to create a gentle taper on the side surface of the resist.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to be able to fabricate various structures, a thick film photoresist layer may be formed on the substrate. When a thick film photoresist layer is formed on the substrate, it is necessary to control the profile of the thick film photoresist layer in order to fabricate a free-form structure.

[0005] However, with the technique described in Patent Document 1, although it is possible to make the taper angle gentle, it is not possible to meet the demands for fabricating various products, such as when it is desired to make the taper angle steep or when it is desired to partially change the taper angle.

[0006] The present invention provides a technique advantageous for increasing the diversity of products by an exposure apparatus.

Means for Solving the Problems

[0007] According to one aspect of the present invention, there is provided a determination method for determining exposure parameter values for performing multi-focus exposure in which a photo resist layer on a substrate is exposed by changing a distance between the substrate and a focus of a projection optical system to each of a plurality of distances by an exposure apparatus for transferring a pattern of a master plate to the substrate, the method including: an acquisition step of obtaining a relationship between an exposure parameter value set which is a set of exposure parameter values for each of the plurality of distances and a resist profile obtained when the multi-focus exposure is performed and developed according to the exposure parameter value set; and a determination step of determining a target exposure parameter value set for obtaining a target resist profile based on the obtained relationship.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a technique advantageous for increasing the diversity of products by an exposure apparatus.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] <First Embodiment> FIG. 1 is a diagram showing the configuration of an exposure apparatus 100 that transfers a pattern of a master plate onto a substrate in an embodiment. In this specification and the drawings, directions are indicated in an XYZ coordinate system with the horizontal plane as the XY plane. Generally, a substrate 114 to be exposed is placed on a substrate stage 115 such that its surface is parallel to the horizontal plane (XY plane). Therefore, hereinafter, in the plane along the substrate mounting surface of the substrate stage 115, the directions orthogonal to each other are defined as the X-axis and the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is defined as the Z-axis. Further, hereinafter, the directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are referred to as the X-direction, Y-direction, and Z-direction, respectively.

[0012] A light source 101 housed in a light source unit 102 can emit radiation light in the far ultraviolet region, for example, with a wavelength of 365 nm. Control for wavelength stabilization in the light source 101, control of the discharge application voltage, etc. can be performed by an illumination system control unit 125.

[0013] The radiation light emitted from the light source 101 is shaped into a predetermined shape by the radiation light shaping optical system 104. The light beam that exits the radiation light shaping optical system 104 is guided through the mirror 105 and the illumination optical system 106 to the original plate 109 held by the original plate stage 110, and the original plate 109 is illuminated. The illumination optical system 106 may include an illumination light adjustment unit 107, a half mirror 108, and a light quantity sensor 118. The illumination light adjustment unit 107 has the function of a wavelength selection unit that selectively passes light of a wavelength used for exposing the substrate 114 among the light incident on the illumination optical system 106. The illumination light adjustment unit 107 as the wavelength selection unit may have, for example, a plurality of wavelength plates that pass light of different wavelengths. The illumination light adjustment unit 107 can selectively pass light of a wavelength used for exposing the substrate 114 by changing the wavelength plate arranged in the optical path among the plurality of wavelength plates. The plurality of wavelength plates may be arranged on a turret, for example. The illumination light adjustment unit 107 can be controlled by the illumination system control unit 125. The light beam that exits the illumination light adjustment unit 107 is also guided to the light quantity sensor 118 through the half mirror 108. The detection result by the light quantity sensor 118 can be provided to the main control unit 130 through the illumination system control unit 125. Further, the illumination system control unit 125 can control the illumination light adjustment unit 107 according to a desired effective light source distribution specified by the main control unit 130. Note that the "effective light source distribution" refers to the light intensity distribution on the pupil plane of the illumination optical system that illuminates the original plate.

[0014] A circuit pattern of a semiconductor element for performing baking is formed on the original plate 109. The original plate stage 110 that holds the original plate 109 can be controlled by the original plate stage driving unit 119 through the original plate stage control unit 126.

[0015] The projection optical system 111 guides the exposure light that has passed through the original plate 109 to the substrate 114 placed on the substrate stage 115. Thereby, the pattern of the original plate 109 is imaged and projected onto the substrate 114 (one shot area thereon) coated with photoresist. The projection optical system 111 is provided with a field lens 112. The lens driving unit 120 can move the field lens 112 in the optical axis direction. By the projection system control unit 127 controlling the position of the field lens 112 in the optical axis direction via the lens driving unit 120, various aberrations of the projection optical system 111 can be suppressed. Also, it is possible to change the focal length by the projection system control unit 127 controlling the position of the field lens 112 in the optical axis direction via the lens driving unit 120. Further, the projection optical system 111 includes a diaphragm unit 113 for aperture control. The diaphragm driving unit 121 drives the diaphragm unit 113. The diaphragm driving unit 121 is controlled by the projection system control unit 127. The projection system control unit 127 issues a driving command to the diaphragm driving unit 121 so as to achieve a desired aperture number specified by the main control unit 130. The diaphragm driving unit 121 drives the diaphragm unit 113 in response to the driving command.

[0016] The substrate stage 115 can hold the substrate 114 and move in the X direction and the Y direction which are orthogonal to each other in the plane perpendicular to the optical axis direction (Z direction) of the projection optical system 111. The laser interferometer 124 can measure the position of the substrate stage 115 in the XY plane by measuring the distance to the moving mirror 116 fixed to the substrate stage 115. The substrate stage control unit 128 controls the substrate stage driving unit 129 composed of a motor or the like based on the position of the substrate stage 115 measured by the laser interferometer 124, thereby moving the substrate stage 115 to a predetermined position in the XY plane.

[0017] The laser interferometer 123 can measure the Z-direction position of the substrate stage 115 by measuring the distance to the moving mirror 116. The substrate stage control unit 128 can move the substrate stage 115 in the Z direction by controlling the substrate stage drive unit 129 based on the Z-direction position of the substrate stage 115 measured by the laser interferometer 123.

[0018] The focus unit 122 has a focus plane detection function. The focus unit 122 projects a plurality of light beams composed of non-exposed light that does not expose the photoresist on the substrate 114 through the projection optical system 111. These light beams are each focused and reflected on the substrate 114 and incident on the detection optical system of the focus unit 122. A plurality of light receiving elements for position detection are arranged in the detection optical system corresponding to each reflected light beam. The light receiving surface of each light receiving element and the reflection point of each light beam on the substrate 114 are configured to be substantially conjugate by the imaging optical system. The positional deviation of the surface of the substrate 114 in the optical axis direction of the projection optical system 111 is measured as the positional deviation of the incident light beam on the light receiving element for position detection in the focus unit 122.

[0019] The main control unit 130 comprehensively controls the illumination system control unit 125, the reticle stage control unit 126, the projection system control unit 127, and the substrate stage control unit 128. The main control unit 130 may be composed of an information processing device (computer) including a processor such as a CPU (Central Processing Unit) and a storage unit such as a memory. In the exposure apparatus 100 shown in FIG. 1, various control units (illumination system control unit 125, reticle stage control unit 126, projection system control unit 127, substrate stage control unit 128) controlled by the main control unit 130 are provided individually. However, the main control unit 130 and each control unit may be provided as one control unit. Also, the main control unit 130 may be arranged inside the housing of the exposure apparatus 100 or outside the exposure apparatus 100. The main control unit 130 arranged outside the exposure apparatus 100 may be realized by, for example, a computer that functions as a control server network-connected to the exposure apparatus 100.

[0020] Further, an exposure shutter 103 may be disposed between the light source unit 102 and the radiation light shaping optical system 104. The opening / closing drive of the exposure shutter 103 can be performed by an exposure shutter drive unit 117. The main control unit 130 can control exposure / non-exposure via the exposure shutter drive unit 117.

[0021] The configuration of the exposure apparatus 100 in the embodiment is generally as described above. In order to be able to fabricate various structures, a thick film photoresist layer may be formed on the substrate 114. When a thick film photoresist layer is formed on the substrate 114, it is necessary to control the profile of the thick film photoresist layer in order to fabricate a free-form structure. Hereinafter, the cross-sectional shape of the photoresist layer is referred to as a "resist profile".

[0022] In the present embodiment, in order to achieve highly free control of the resist profile, multi-focus exposure is performed by the exposure apparatus 100. Multi-focus exposure is to perform multiple exposures on the photoresist layer on the substrate 114 by changing the distance in the Z direction (hereinafter, may be referred to as "focal length") between the substrate 114 and the focus of the projection optical system 111. Multi-focus exposure can be performed, for example, by changing the distance between the substrate 114 and the focus of the projection optical system 111 to each of a plurality of distances and exposing the photoresist layer on the substrate 114. Alternatively, multi-focus exposure may be performed by exposing the photoresist layer on the substrate 114 while continuously changing the distance between the substrate 114 and the focus of the projection optical system 111. Alternatively, multi-focus exposure may be performed by tilting and driving the substrate 114 obliquely to continuously change the distance from the focus of the projection optical system 111 and exposing the photoresist layer on the substrate 114.

[0023] In conventional multi-focus exposure, regardless of the focal length, the amount of light (hereinafter sometimes referred to as "irradiation light amount") irradiated on the photoresist layer on the substrate 114 was made constant. Therefore, it was difficult to freely control the resist profile by conventional multi-focus exposure. On the other hand, in the present embodiment, the irradiation light amount in multi-focus exposure is made different according to the focal length, so as to obtain a desired resist profile.

[0024] The change in the focal length can be performed by moving at least any one of the substrate 114, the original plate 109, and the lens (field lens 112) of the projection optical system 111. The movement of the substrate 114 can be performed, for example, by driving the substrate stage 115 in the Z direction by the substrate stage driving unit 129. The movement of the original plate 109 can be performed, for example, by driving the original plate stage 110 in the Z direction by the original plate stage driving unit 119. The movement of the field lens 112 of the projection optical system 111 can be performed, for example, by driving the field lens 112 in the Z direction by the lens driving unit 120. Hereinafter, an example in which the focal length is changed by driving the substrate stage 115 in the Z direction will be described. As described above, the substrate stage driving unit 129, the original plate stage driving unit 119, and the lens driving unit 120 can function as a changing unit for changing the focal length.

[0025] The focal length may be changed by changing the exposure light wavelength. The exposure light wavelength refers to the wavelength of the light emitted from the projection optical system 111. The change in the exposure light wavelength can be performed, for example, by the illumination light adjustment unit 107. The illumination light adjustment unit 107 is controlled by the illumination system control unit 125 so that the light emitted from the projection optical system 111 has a desired wavelength. Also, the change in the exposure light wavelength may be performed by the light source unit 102. For example, if the light source 101 is a laser light source, the exposure light wavelength may be changed by changing the position of the diffraction grating included in the light source unit 102 by an actuator such as a piezo element. Alternatively, when the light source 101 is a plurality of laser light sources that emit laser lights having different wavelengths, the wavelength may be changed by causing at least one of the plurality of laser light sources to emit laser light.

[0026] The irradiation light quantity can be controlled (changed) by at least one of the intensity of the light irradiating the photoresist layer on the substrate 114, the time for irradiating the photoresist layer on the substrate 114 with light, and the speed of changing the focal length. The intensity of the light irradiating the photoresist layer on the substrate 114 can be controlled, for example, by changing the intensity of the light emitted from the light source unit 102. The intensity of the light emitted from the light source unit 102 is controlled by the illumination system control unit 125 so as to be the intensity of the light instructed by the main control unit 130. The time for irradiating the photoresist layer on the substrate 114 with light can be controlled, for example, by driving the exposure shutter 103 by the exposure shutter drive unit 117. The speed of changing the focal length can be controlled by at least one of, for example, the relative driving speed between the substrate 114 and the projection optical system 111, the relative driving speed between the original plate 109 and the projection optical system 111, and the driving speed of the field lens 112 of the projection optical system 111. Further, the speed of changing the focal length may be controlled (changed) by the speed of changing the wavelength of the light emitted from the projection optical system 111. The control of the speed of changing the wavelength can be the same control as the wavelength change described above. When the light source 101 is a laser light source, the control of the speed of changing the wavelength may be performed by changing the oscillation time for each wavelength, or by changing the wavelength presence probability for each pulse, or by changing the intensities of a plurality of laser lights having different wavelengths from each other.

[0027] (Example 1) Hereinafter, as a multi-focus exposure method, it is assumed that a method of changing the distance between the substrate 114 and the focus of the projection optical system 111 to each of a plurality of distances and exposing the photoresist layer on the substrate 114 is adopted. When performing multi-focus exposure, it is necessary to determine a set of exposure parameter values (exposure parameter value set) for each of a plurality of distances (a plurality of focal lengths). In the present embodiment, the determination method for determining the target exposure parameter value set for obtaining the target resist profile is performed as follows.

[0028] First, the relationship between the exposure parameter value set and the resist profile obtained when performing multi-focus exposure and development according to this exposure parameter value set is acquired (acquisition step). In this acquisition step, the resist profile may be obtained by actually performing exposure and development and observing the cross-section of the photoresist layer with an electron microscope. Alternatively, the resist profile may be obtained by simulation using the main control unit 130 or other computers. Then, based on the relationship between the obtained exposure parameter value set and the resist profile, the target exposure parameter value set is determined.

[0029] Hereinafter, a specific example of a determination method for determining the target exposure parameter value set for obtaining the target resist profile will be described. FIG. 2 is a flowchart showing the determination method. When the determination method is performed by simulation, a program corresponding to this flowchart is stored, for example, in the storage unit of the main control unit 130 and executed by the main control unit 130.

[0030] In S201, according to the first exposure parameter value set, the focal length is changed to each of a plurality of distances to perform multi-focus exposure and develop the resist to obtain a first resist profile. FIG. 3(a) shows an example of a first resist profile 302 obtained by performing multi-focus exposure on the substrate 114 by changing the focal length to each of a plurality of focal lengths 303, 304, 305, and 306 according to the first exposure parameter value set and then developing. The focal length 303 corresponds to the position of the surface of the photoresist layer before exposure (the upper end of the opening formed in the photoresist layer after development, which may be simply referred to as the "opening" hereinafter), and the focal length 306 corresponds to the position of the interface between the photoresist layer and the substrate 114. The exposure parameter is the irradiation light amount. Therefore, the first exposure parameter value set includes the irradiation light amounts 307, 308, 309, and 310 at each focal position. In FIG. 3(a), the magnitudes of the irradiation light amounts 307, 308, 309, and 310 at each focal position constituting the first exposure parameter value set are represented by the sizes of the circles. Here, as shown in FIG. 3(a), the irradiation light amounts 307, 308, 309, and 310 at each focal position constituting the first exposure parameter value set are the same.

[0031] In S202, according to the second exposure parameter value set, the focal length is changed to each of a plurality of distances to perform multi-focus exposure and develop the resist to obtain a second resist profile. FIG. 3(b) shows an example of a second resist profile 312 obtained by performing multi-focus exposure on the substrate 114 by changing the focal length to each of a plurality of focal lengths 303, 304, 305, and 306 according to the second exposure parameter value set and then developing. The second exposure parameter value set includes the irradiation light amounts 313, 314, 315, and 316 at each focal position. In FIG. 3(b), the magnitudes of the irradiation light amounts 313, 314, 315, and 316 at each focal position constituting the second exposure parameter value set are represented by the sizes of the circles. Here, as shown in FIG. 3(b), the irradiation light amounts 313, 314, 315, and 316 at each focal position constituting the second exposure parameter value set are set to gradually increase. That is, Irradiation light amount 313 < irradiation light amount 314 < irradiation light amount 315 < irradiation light amount 316 It is.

[0032] In S203, one of the plurality of focal lengths 303, 304, 305, 306 (for example, focal length 303) is set as the target focal length.

[0033] In S204, from the first resist profile obtained in S201, a first evaluation value, which is an evaluation value of the cross-sectional shape of the opening formed in the photoresist layer after development at the target focal length, is obtained (first step). The evaluation value is, for example, a CD (Critical Dimension) value indicating the width (line width) of the opening.

[0034] In S205, from the second resist profile obtained in S201, a second evaluation value (CD value), which is an evaluation value of the cross-sectional shape of the opening formed in the photoresist layer after development at the target focal length, is obtained (second step).

[0035] In S206, based on the difference between the first exposure parameter value (irradiation light amount) and the second exposure parameter value (irradiation light amount) at the target focal length, and the difference between the first evaluation value and the second evaluation value, the sensitivity is obtained (third step). The sensitivity indicates the amount of change in the evaluation value (CD value change amount) per unit change in the exposure parameter value (irradiation light amount change). For example, if the first exposure parameter value (irradiation light amount) is E1, the second exposure parameter value (irradiation light amount) is E2, the first evaluation value (CD value) is CD1, and the second evaluation value (CD value) is CD2, then the sensitivity Sens is Sens=(CD2 - CD1) / (E2 - E1) represented by.

[0036] In S207, it is determined whether there is a next focus distance to be noted. When the sensitivities for all four focus distances have been obtained, the process proceeds to S208; otherwise, the process returns to S203 and the process is repeated for the next focus distance to be noted. Thus, by repeating the first step, the second step, and the third step for each of the plurality of focus distances, the sensitivity by distance is obtained. The sensitivity by distance is a set of sensitivities Sens for each of the plurality of focus distances 303, 304, 305, 306, and this represents the relationship between the exposure parameter value set and the resist profile obtained.

[0037] In S208, an interpolation operation based on the sensitivity by distance is performed to determine the target exposure parameter value set.

[0038] In the above example, the CD value indicating the width (line width) of the aperture is used as the evaluation value, but it is not limited to this. The evaluation value may be an index of the cross-sectional shape of the aperture. For example, the evaluation value may include at least any one of the CD value, the sidewall angle of the cross-sectional shape of the aperture, and the ratio (T / B) of the upper end width to the lower end width of the aperture.

[0039] Also, in the above example, the number of the plurality of focus distances is four points, but it is not limited to this. Depending on the thickness of the photoresist layer, the complexity required for the shape of the resist profile, etc., the number of the plurality of focus distances may be five points or more, or may be three points or less.

[0040] (Example 2) Also, in the above Example 1, the irradiation light amount is used as the exposure parameter value, but it is not limited to this. The exposure parameter value may be at least any one of the irradiation light amount, the number of apertures, the effective light source distribution, the exposure wavelength, and the wavelength width.

[0041] Figures 4(a) and (b) show examples of resist profiles when the numerical aperture is used as the exposure parameter value. The numerical aperture can be controlled by driving the aperture unit 113 of the projection optical system 111 with the aperture drive unit 121. Figure 4(a) shows an example of a first resist profile 402 obtained when multiple focus exposures are performed by changing to each of a plurality of focal lengths 403, 404, 405, 406 in accordance with a first set of exposure parameter values (numerical aperture) for the substrate 114 and then developing. The focal length 403 corresponds to the position of the surface (the upper end of the aperture) of the photoresist layer before exposure, and the focal length 406 corresponds to the position of the interface between the photoresist layer and the substrate 114. The first set of exposure parameter values includes the numerical apertures 407, 408, 409, 410 at each focal position. In Figure 4(a), the numerical apertures 407, 408, 409, 410 at each focal position constituting the first set of exposure parameter values are represented by the size of the circles. Here, as shown in Figure 4(a), the numerical apertures 407, 408, 409, 410 at each focal position constituting the first set of exposure parameter values are the same.

[0042] Figure 4(b) shows an example of a second resist profile 412 obtained when multiple focus exposures are performed by changing to each of a plurality of focal lengths 403, 404, 405, 406 in accordance with a second set of exposure parameter values for the substrate 114 and then developing. The second set of exposure parameter values (numerical aperture) includes the numerical apertures 413, 414, 415, 416 at each focal position. In Figure 4(b), the numerical apertures 413, 414, 415, 416 at each focal position constituting the second set of exposure parameter values are represented by the size of the circles. Here, as shown in Figure 4(b), the numerical apertures 413, 414, 415, 416 at each focal position constituting the second set of exposure parameter values are set to gradually increase. That is, numerical aperture 413 < numerical aperture 414 < numerical aperture 415 < numerical aperture 416 is true.

[0043] Thus, instead of the exposure light amount used as the exposure parameter value in Example 1, the numerical aperture can be used. Therefore, regarding the description of the determination method (FIG. 2) for determining the target exposure parameter value set for obtaining the target resist profile shown in Example 1, the exposure light amount can be read as the numerical aperture and applied.

[0044] <Embodiment of article manufacturing method> The article manufacturing method according to the embodiment of the present invention is suitable for manufacturing articles such as microdevices such as semiconductor devices and elements having fine structures. The article manufacturing method of this embodiment includes a step of forming a latent image pattern (a step of exposing a substrate) on a photosensitive agent applied to a substrate using the above-described exposure apparatus, and a step of developing the substrate on which the latent image pattern is formed in such a step. Further, such a manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method of this embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

[0045] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiment to a system or apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or apparatus to read and execute the program. Further, it can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

[0046] The disclosure of this specification includes at least the following technical ideas. (Item 1) A determination method for determining an exposure parameter value for performing multi-focus exposure in which a distance between the substrate and a focus of a projection optical system is changed to each of a plurality of distances to expose a photoresist layer on the substrate by an exposure apparatus that transfers an original pattern to the substrate, An acquisition step of obtaining a relationship between an exposure parameter value set, which is a set of exposure parameter values for each of the plurality of distances, and a resist profile indicating a cross-sectional shape of the photoresist layer obtained when the multi-focus exposure is performed and developed according to the exposure parameter value set; A determination step of determining a target exposure parameter value set for obtaining a target resist profile based on the obtained relationship; A determination method characterized by comprising the above. (Item 2) The acquisition step includes: A step of obtaining a first resist profile when the multi-focus exposure is performed and developed according to a first exposure parameter value set; A step of obtaining a second resist profile when the multi-focus exposure is performed and developed according to a second exposure parameter value set different from the first exposure parameter value set; The relationship is obtained based on the difference between the first exposure parameter value set and the second exposure parameter value set and the difference between the first resist profile and the second resist profile. The determination method according to Item 1, characterized by this. (Item 3) The acquisition step includes: A first step of obtaining a first evaluation value, which is an evaluation value of a cross-sectional shape of an opening formed in the photoresist layer after development, from the first resist profile; A second step of obtaining a second evaluation value, which is an evaluation value of a cross-sectional shape of an opening formed in the photoresist layer after development, from the second resist profile; A third step of obtaining a sensitivity indicating a change amount of the evaluation value per unit change of the exposure parameter value based on the difference between the first exposure parameter value in the first exposure parameter value set and the second exposure parameter value in the second exposure parameter value set and the difference between the first evaluation value and the second evaluation value; By repeating the first step, the second step, and the third step for each of the plurality of distances, a sensitivity for each distance is obtained. The determination method according to Item 2, characterized by this. (Item 4) The determination step determines the set of target exposure parameter values by interpolation calculation based on the sensitivity according to distance, and is the determination method according to item 3, characterized in that. (Item 5) The evaluation value includes at least any one of a CD value indicating the width of the aperture, a sidewall angle of the cross-sectional shape, and a ratio of the upper end width to the lower end width of the aperture, and is the determination method according to item 3 or 4, characterized in that. (Item 6) The change in the distance is performed by moving at least any one of the substrate, the reticle, and the lens of the projection optical system, and is the determination method according to any one of items 1 to 5, characterized in that. (Item 7) The change in the distance is performed by changing the exposure wavelength, and is the determination method according to any one of items 1 to 5, characterized in that. (Item 8) The exposure parameter value is at least any one of the irradiation light amount, the numerical aperture, the effective light source distribution, the exposure wavelength, and the wavelength width, and is the determination method according to any one of items 1 to 7, characterized in that. (Item 9) A program for causing a computer to execute each step of the determination method according to any one of items 1 to 8. (Item 10) An exposure apparatus for transferring a pattern of a reticle onto a substrate, A projection optical system that projects the pattern of the reticle onto the substrate, A changing unit that changes the distance between the substrate and the focus of the projection optical system to each of a plurality of distances, A control unit that performs multi-focus exposure in which the distance is changed to each of the plurality of distances by the changing unit to expose a photoresist layer on the substrate, having The control unit determines a set of target exposure parameter values for obtaining a target resist profile based on the relationship between an exposure parameter value set, which is a set of exposure parameter values for each of the plurality of distances, and a resist profile indicating the cross-sectional shape of the photoresist layer obtained when performing and developing the multi-focus exposure according to the exposure parameter value set. An exposure apparatus characterized by the above. (Item 11) A step of exposing a substrate using the exposure apparatus according to Item 10, A step of developing the exposed substrate, A method for manufacturing an article, comprising the above steps and manufacturing an article from the developed substrate.

[0047] The invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, claims are attached to disclose the scope of the invention.

Explanation of Reference Numerals

[0048] 100: Exposure apparatus, 109: Master mask, 111: Projection optical system, 114: Substrate, 115: Substrate stage, 130: Main control unit

Claims

1. A determination method for determining exposure parameter values for performing multi-focus exposure in which a photo resist layer on a substrate is exposed by changing the distance between the substrate and the focus of a projection optical system to each of a plurality of distances by an exposure apparatus that transfers an original pattern onto the substrate, an acquisition step of obtaining a relationship between an exposure parameter value set which is a set of exposure parameter values for each of the plurality of distances, and a resist profile showing a cross-sectional shape of the photo resist layer obtained when the multi-focus exposure is performed and developed according to the exposure parameter value set, a determination step of determining a target exposure parameter value set for obtaining a target resist profile based on the obtained relationship, characterized by comprising the above.

2. The acquisition step is, a step of obtaining a first resist profile when the multi-focus exposure is performed and developed according to a first exposure parameter value set, a step of obtaining a second resist profile when the multi-focus exposure is performed and developed according to a second exposure parameter value set different from the first exposure parameter value set, including obtaining the relationship based on the difference between the first exposure parameter value set and the second exposure parameter value set and the difference between the first resist profile and the second resist profile. The determination method according to claim 1, characterized by this.

3. The acquisition step is, a first step of obtaining a first evaluation value which is an evaluation value of a cross-sectional shape of an opening formed in the photo resist layer after development from the first resist profile, a second step of obtaining a second evaluation value which is an evaluation value of a cross-sectional shape of an opening formed in the photo resist layer after development from the second resist profile, a third step of obtaining a sensitivity indicating a change amount of the evaluation value per unit change of the exposure parameter value based on the difference between the first exposure parameter value in the first exposure parameter value set and the second exposure parameter value in the second exposure parameter value set and the difference between the first evaluation value and the second evaluation value, including repeating the first step, the second step, and the third step for each of the plurality of distances to obtain a sensitivity for each distance. The determination method according to claim 2, characterized by this.

4. The determination step determines the target exposure parameter value set by interpolation calculation based on the sensitivity for each distance. The determination method according to claim 3, characterized by this.

5. The determination method according to claim 3, wherein the evaluation value includes at least any one of a CD value indicating the width of the opening, a side wall angle of the cross-sectional shape, and a ratio of an upper end width to a lower end width of the opening.

6. The determination method according to claim 1, wherein the change in the distance is performed by moving at least any one of the substrate, the reticle, and the lens of the projection optical system.

7. The determination method according to claim 1, wherein the change in the distance is performed by changing an exposure wavelength.

8. The determination method according to claim 1, wherein the exposure parameter value is at least any one of an irradiation light amount, a numerical aperture, an effective light source distribution, an exposure wavelength, and a wavelength width.

9. A program for causing a computer to execute each step of the determination method according to any one of claims 1 to 8.

10. An exposure apparatus for transferring a pattern of a reticle onto a substrate, a projection optical system that projects the pattern of the reticle onto the substrate, a changing unit that changes the distance between the substrate and the focus of the projection optical system to each of a plurality of distances, a control unit that performs multi-focus exposure in which the distance is changed to each of the plurality of distances by the changing unit to expose a photoresist layer on the substrate, comprising: The control unit determines a target exposure parameter value set for obtaining a target resist profile based on a relationship between an exposure parameter value set that is a set of exposure parameter values for each of the plurality of distances and a resist profile indicating a cross-sectional shape of the photoresist layer obtained when performing the multi-focus exposure and development according to the exposure parameter value set. An exposure apparatus characterized by the above.

11. A step of exposing a substrate using the exposure apparatus according to claim 10, a step of developing the exposed substrate, A method for manufacturing an article, comprising manufacturing an article from the developed substrate.

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