Measurement method, adjustment method, exposure apparatus, and method for manufacturing articles

Abstract

To provide a technology advantageous for measuring diffracted light generated by periodic polishing marks present on a surface of an optical element constituting a test optical system.SOLUTION: A measurement method for measuring diffracted light generated in a test optical system, comprises: a first step where the light from a measurement pattern including an aperture and a shielding part surrounding the aperture arranged on an object plane of the test optical system detects a light intensity distribution formed on an image plane of the test optical system via the test optical system; and a second step of obtaining information regarding diffracted light generated in the test optical system due to the periodic polishing marks existing on the surface of an optical element constituting the test optical system on the basis of the light intensity distribution detected in the first step.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] In the manufacture of semiconductor devices and flat panel displays (FPDs), generally, an exposure apparatus is used which illuminates a reticle (reticle or mask) and transfers the pattern formed on the reticle onto a substrate coated with a photosensitive agent (resist) through a projection optical system. In recent years, as semiconductor devices and FPDs have become more highly refined and the accuracy required for exposure apparatuses has increased, factors that interfere with accurate pattern transfer include stray light such as flare and ghost generated in the projection optical system.

[0003] Flare generated in the projection optical system is roughly classified into long-range flare and local flare. Long-range flare is mainly caused by multiple reflected light from a film provided on the surface of an optical element in the projection optical system. Local flare is mainly caused by scattered light due to irregular unevenness on the surface of an optical element in the projection optical system. Further, when a periodic structure such as a diffraction grating exists on the surface of an optical element in the projection optical system, diffracted light is generated by such a structure, and a large amount of light may gather and form an image at a specific position. Such light is called ghost, and is considered to be mainly caused by polishing marks remaining due to periodic polishing of the optical element, for example.

[0004] Conventionally, as an evaluation method for evaluating flare, generally, the Kirk method is known (see Non-Patent Document 1). In the Kirk method, the substrate is exposed a plurality of times while changing the exposure amount through a pattern composed of a shielding portion (light-shielding portion) and an opening portion surrounding the same. Then, the exposure amount at which the resist disappears at the imaging position of the opening portion and the exposure amount at which the resist disappears at the imaging position of the shielding portion are obtained, and the ratio thereof is used as an index of the flare rate. Thereby, the amount of light jumping from the entire area of the opening portion to the imaging position of the shielding portion, that is, the flare amount, can be estimated (measured).

Prior Art Documents

[0005] [Non-Patent Document 1] Joseph P.Kirk, Scattered light in photo lithographic lenses. SPIE Vol.2197, 1994 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Because ghosts are formed when diffracted light (diffracted light) is imaged at a specific location (distance and direction), they can have a greater impact on the pattern transferred to the substrate compared to other flares. However, the Kirk method measures the amount of flare from the entire aperture surrounding the shielding area, and therefore cannot measure only specific components such as ghosts.

[0007] This invention has been made in view of the problems of the prior art, and its exemplary objective is to provide a technique advantageous for measuring diffracted light caused by periodic polishing marks present on the surface of optical elements constituting an optical system under test. [Means for solving the problem]

[0008] To achieve the above objective, a measurement method as one aspect of the present invention is a measurement method for measuring diffracted light generated in an optical system under test, characterized by comprising: a first step of detecting a light intensity distribution formed on the image plane of the optical system under test by light from a measurement pattern including an aperture and a shielding portion surrounding the aperture, which is arranged on the object surface of the optical system under test, via the optical system under test; and a second step of obtaining information about diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical elements constituting the optical system under test, based on the light intensity distribution detected in the first step.

[0009] Further objects or other aspects of the present invention will be revealed by embodiments described below with reference to the accompanying drawings. [Effects of the Invention]

[0010] According to the present invention, for example, it is possible to provide a technique that is advantageous for measuring diffracted light caused by periodic polishing marks present on the surface of optical elements constituting an optical system under test. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing the configuration of the exposure apparatus. [Figure 2] This diagram schematically shows polishing marks present on the surface of the optical elements that make up the projection optical system. [Figure 3] This diagram schematically shows the measurement pattern. [Figure 4] This figure shows an example of the light intensity distribution formed on the image plane of the projection optical system by light from a measurement pattern. [Figure 5] This diagram illustrates a method for detecting the light intensity distribution formed by light from a measurement pattern. [Figure 6] This diagram illustrates a method for detecting the light intensity distribution formed by light from a measurement pattern. [Figure 7] This diagram illustrates a method for detecting the light intensity distribution formed by light from a measurement pattern. [Figure 8] This is a flowchart illustrating the process of adjusting the projection optics system. [Modes for carrying out the invention]

[0012] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0013] Figure 1 is a schematic diagram showing the configuration of an exposure apparatus 1 having a projection optical system 15 to which a measurement method as one aspect of the present invention is applied (i.e., as an optical system under test). The exposure apparatus 1 is a lithography apparatus used, for example, in the lithography process of various devices, to form a pattern on a substrate. The exposure apparatus 1 exposes the substrate through a master plate (reticle or mask) on which a pattern to be transferred to the substrate (e.g., a circuit pattern) is formed, and transfers the pattern of the master plate to the substrate.

[0014] As shown in Figure 1, the exposure apparatus 1 includes an illumination optical system 11, a master plate stage 13, a projection optical system 15, a substrate stage 16, a sensor 17, and a control unit CU.

[0015] The illumination optical system 11 uniformly illuminates the master plate held on the master plate stage 13. The master plates held on the master plate stage 13 include not only a pattern transfer master plate (not shown) on which a pattern to be transferred to a substrate is formed, but also, in this embodiment, a measurement master plate 12 used when measuring (evaluating) the diffracted light generated by the projection optical system 15. The measurement master plate 12 is provided with a measurement pattern 14 for measuring the diffracted light generated by the projection optical system 15. The measurement pattern 14 is placed on the object surface of the projection optical system 15 when measuring the diffracted light generated by the projection optical system 15. The measurement pattern 14 may be provided on the pattern transfer master plate or on the master plate stage 13.

[0016] The projection optical system 15 is an optical system including a plurality of optical elements 15a, 15b, and 15c. The projection optical system 15 projects (transfers) the pattern of the original plate for pattern transfer held on the original plate stage 13 onto a substrate (not shown) held on the substrate stage 16 via the plurality of optical elements 15a, 15b, and 15c. Further, the projection optical system 15 projects the measurement pattern 14 of the measurement original plate 12 held on the original plate stage 13 and arranged on the image plane of the projection optical system 15 onto the image plane of the projection optical system 15 via the plurality of optical elements 15a, 15b, and 15c.

[0017] On the substrate stage 16, a sensor 17 is provided which is arranged on the image plane of the projection optical system 15 and detects the light (light quantity) incident (reaching) on the image plane of the projection optical system 15. In this embodiment, the sensor 17 is used to detect the light intensity distribution formed on the image plane of the projection optical system 15 from the light of the measurement pattern 14 of the measurement original plate 12 arranged on the object plane of the projection optical system 15 via the projection optical system 15. The sensor 17 can be used in combination with, for example, a light quantity sensor provided to obtain the best focus position under the illumination condition in which the illumination optical system 11 illuminates the original plate for pattern transfer in order to accurately transfer the pattern of the original plate for pattern transfer onto the substrate. Further, as the sensor 17, a two-dimensional sensor or the like can also be used.

[0018] When there is a factor causing diffracted light in the projection optical system 15, the diffracted light generated in the projection optical system 15 can be detected by arranging the sensor 17 at the imaging position of such diffracted light. In this embodiment, as the diffracted light generated in the projection optical system 15, a periodic structure such as a diffraction grating existing on the surface of the optical element 15a, 15b, or 15c constituting the projection optical system 15 is assumed, specifically, diffracted light caused by periodic polishing marks, so-called ghosts.

[0019] The control unit CU is composed of a computer (information processing device) including, for example, a CPU and a memory, and comprehensively controls each part of the exposure apparatus 1 according to the program stored in the storage unit. In the present embodiment, the control unit CU controls the process of transferring the pattern of the original plate for pattern transfer to the substrate (exposure process). Further, in the present embodiment, the control unit CU also controls the process of measuring the diffracted light (ghost) generated in the projection optical system 15 due to the periodic polishing marks present on the surface of the optical element constituting the projection optical system 15 (measurement process).

[0020] Hereinafter, the configuration of the measurement pattern 14 for measuring the diffracted light generated in the projection optical system 15 due to the periodic polishing marks present on the surface of the optical element constituting the projection optical system 15 will be described.

[0021] First, consider the case where there is a wavefront aberration of a specific frequency in the projection optical system 15. As described above, factors that cause a wavefront aberration of a specific frequency in the projection optical system 15 include periodic polishing to improve the surface accuracy of the optical element constituting the projection optical system 15, and polishing marks remaining on such a surface. Here, consider the case where there are polishing marks having a periodic structure with a frequency of P on the surface of the optical element 15a. The specific frequency f of the wavefront aberration of the projection optical system 15 caused by such polishing marks is expressed by the following formula (1) when the pupil diameter of the projection optical system 15 is 1 and the beam diameter on the surface of the optical element 15a is D.

[0022]

Equation

[0023] Figure 2 is a schematic diagram showing the polishing marks (periodic structure) present on the surface of the optical element 15a from the side of the measurement plate 12. When polishing marks like those shown in Figure 2 are present, in addition to the normal light that has passed through the aperture of the measurement pattern 14, the light diffracted in the periodic direction (first direction) of the polishing marks (diffracted light, so-called ghost) is also imaged on the image plane of the projection optical system 15. The distance L between the normal light and the diffracted light on the image plane of the projection optical system 15 is expressed by the following equation (2), where λ is the wavelength of the exposure light (wavelength of the light illuminating the measurement pattern 14) and NA is the numerical aperture of the projection optical system 15, and a specific frequency f of the wavefront aberration of the projection optical system 15 is used.

[0024]

number

[0025] Figure 3 is a schematic diagram showing a measurement pattern 14 provided on the measurement master plate 12. The measurement pattern 14 includes an aperture 31 and a shielding portion 32 provided around the aperture 31 and surrounding the aperture 31 in order to separate normal light and diffracted light. Here, the aperture diameter R of the aperture 31 is preferably defined as shown in the following equation (3) using a specific frequency f of the wavefront aberration of the projection optical system 15, the numerical aperture NA of the projection optical system 15, and the wavelength λ of the exposure light.

[0026]

number

[0027] Here, if the wavelength λ of the exposure light has multiple peak wavelengths, such as in a high-pressure mercury lamp, it is preferable to define the aperture diameter R of the aperture 31 from the shortest peak wavelength among the multiple peak wavelengths.

[0028] Furthermore, the shielding portion 32 is provided such that there is no influence from light from outside the shielding portion 32 at the imaging position of the diffracted light on the image plane of the projection optical system 15. Specifically, as shown in Figure 3, it is preferable to define the distance S between the opening end (outer circumference) of the aperture 31 and the outer end (outer circumference) of the shielding portion 32 as shown in the following equation (4).

[0029]

Number

[0030] Note that, there may be a case where periodic polishing marks (structures) different from those on the surface of the optical element 15a exist on the surfaces of optical elements 15b and 15c different from the optical element 15a that constitutes the projection optical system 15. Even in such a case, it is possible to separate the regular light and the diffracted light on the image plane of the projection optical system 15. When the frequencies of the polishing marks existing on the respective surfaces of the optical elements 15a to 15c are different, the diffracted light caused by those polishing marks forms images at different positions on the image plane of the projection optical system 15. Here, let the distances between the imaging position of the aperture 31 and the imaging positions of the diffracted light caused by the polishing marks existing on the respective surfaces of the optical elements 15a to 15c be La, Lb, Lc (La < Lb < Lc). Also, let the frequencies of the polishing marks existing on the respective surfaces of the optical elements 15a to 15c be Pa, Pb, Pc (Pa > Pb > Pc), and let the beam diameters on the respective surfaces of the optical elements 15a to 15c be Da, Db, Dc. In this case, the distances La, Lb, Lc between the imaging position of the aperture 31 and the imaging position of the diffracted light are represented by the following formula (5) from formula (1) and formula (2).

[0031]

Number

[0032] Therefore, in the projection optical system 15, when there are a plurality of factors causing wavefront aberration of a specific frequency, the aperture diameter R of the aperture 31 is defined from the minimum frequency, and the distance S between the aperture end of the aperture 31 and the outer end of the shielding portion 32 is defined from the maximum frequency. Thereby, the diffracted light caused by a plurality of factors can be separated well from the regular light.

[0033] Specifically, the aperture diameter R of the aperture 31 is defined as shown in equation (6) below, and the distance S between the aperture end of the aperture 31 and the outer end of the shielding portion 32 is defined as shown in equation (7) below. As a result, an intensity distribution (light quantity distribution) as shown in Figure 4 is obtained on the image plane of the projection optical system 15, and wavefront aberrations of specific frequencies can be well separated.

[0034]

number

[0035]

number

[0036] When a measurement pattern 14 satisfying the above-described requirements is placed on the measurement master plate 12 (or master plate stage 13) and positioned on the object plane of the projection optical system 15, the normal light and diffracted light are well separated on the image plane of the projection optical system 15. Therefore, the ratio of the light intensity at the imaging position of the aperture 31 to the light intensity at the imaging position of the diffracted light becomes the proportion of diffracted light generated in the projection optical system 15. This makes it possible to quantitatively evaluate (quantify) diffracted light, so-called ghosting, that is imaged at a specific position (distance and direction) on the image plane of the projection optical system 15 due to periodic polishing marks (structure) present on the surface of the optical elements constituting the projection optical system 15.

[0037] As described above, in this embodiment, the measurement process (measurement method) for measuring diffracted light (ghost) generated in the projection optical system 15 mainly comprises a first step and a second step, as described below. In the first step, the light intensity distribution (Figure 4) formed on the image plane of the projection optical system 15 by light from a measurement pattern 14 placed on the object surface of the projection optical system 15 via the projection optical system 15 which includes a plurality of optical elements 15a to 15c is detected by a sensor 17. In the second step, based on the light intensity distribution detected in the first step, information regarding diffracted light generated in the projection optical system 15 due to periodic polishing marks present on the surfaces of the optical elements 15a to 15c constituting the projection optical system 15 is obtained. The information regarding diffracted light includes, for example, information indicating the position (distance and direction from the center of the aperture 31) and light intensity of the diffracted light on the image plane of the projection optical system 15.

[0038] Here, with reference to Figures 5(a), 5(b), and 5(c), a method (first step) for detecting the light intensity distribution formed on the image plane of the projection optical system 15 by light from a measurement pattern 14 placed on the object plane of the projection optical system 15 will be specifically described. As shown in Figure 5(c), this light intensity distribution includes the light intensity at the imaging position of the aperture 31 of the measurement pattern 14 and the light intensity at the imaging position of the diffracted light.

[0039] The light intensity distribution formed on the image plane of the projection optical system 15 by the light from the measurement pattern 14 is detected by moving (scanning) the sensor 17 within the image plane of the projection optical system 15. Specifically, as shown in Figures 5(a) and 5(b), the sensor 17 is moved within the image plane of the projection optical system 15 in the same direction (first direction) as the periodic direction of the polishing marks present on the surface of the optical elements constituting the projection optical system 15. As described above, these optical elements are subjected to periodic polishing, so the periodic direction (first direction) of the polishing marks present on the surface of the optical elements is basically known. However, even if the periodic direction of the polishing marks present on the surface of the optical elements is unknown, it is possible to detect the light intensity distribution formed on the image plane of the projection optical system 15 by the light from the measurement pattern 14 by appropriately setting the size (dimensions) of the sensor 17. Specifically, as shown in Figure 6(a), it is preferable to define the longitudinal size Y of the sensor 17 using the distance L between the imaging position of the aperture 31 and the imaging position of the diffracted light, and the aperture diameter R of the aperture 31, as shown in the following equation (8).

[0040]

number

[0041] This allows us to determine the angle θ between the direction of movement of the sensor 17 (scanning direction) and the periodic direction of the polishing marks (first direction) from the detection position of the diffracted light and the distance the sensor 17 travels (scanning length) when the diffracted light is detected. Furthermore, as shown in Figure 6(c), we can obtain an optical intensity distribution that includes the optical intensity at the imaging position of the aperture 31 (optical intensity of normal light) and the optical intensity at the imaging position of the diffracted light (optical intensity of diffracted light).

[0042] Furthermore, in this embodiment, the sensor 17 is moved (scanned) as a method for detecting the light intensity distribution formed on the image plane of the projection optical system 15 by the light from the measurement pattern 14, but this is not the only method. Any method can be used as long as it is possible to obtain a light intensity distribution (Figures 5(c) and 6(b)) that includes the light intensity at the imaging position of the aperture 31 and the light intensity at the imaging position of the diffracted light. For example, a two-dimensional sensor capable of detecting a region including the imaging position of the aperture 31 and the imaging position of the diffracted light may be used as the sensor 17.

[0043] Furthermore, in the projection optical system 15, in addition to diffracted light (ghost) caused by periodic polishing marks on the surface of the optical elements constituting the projection optical system 15, flares (stray light) may also be present. Such flares include, for example, local flares caused by irregular irregularities on the surface of the optical elements constituting the projection optical system 15.

[0044] The following describes a method for more accurately detecting the light intensity of diffracted light by reducing the effect of flare, in the case where diffracted light caused by periodic polishing marks on the surface of the optical elements constituting the projection optical system 15 and flare (stray light) are present.

[0045] First, as shown in Figure 7(a), the sensor 17 is moved (scanned) within the image plane of the projection optical system 15 in the same direction (first direction) as the periodic direction of the polishing marks present on the surface of the optical elements constituting the projection optical system 15. As a result, the sensor 17 detects a light intensity distribution as shown in Figure 7(b), that is, a light intensity distribution including the light intensity at the imaging position of the aperture 31 of the measurement pattern 14, the light intensity at the imaging position of the diffracted light, and the light intensity of the flare described above.

[0046] Next, as shown in Figure 7(a), the sensor 17 is moved within the image plane of the projection optical system 15 in a direction intersecting the same direction as the periodic direction of the polishing marks present on the surface of the optical elements constituting the projection optical system 15 (first direction) (a second direction different from the first direction). The second direction includes the imaging position of the aperture 31 (normal light) but does not include the imaging position of the diffracted light. Specifically, if the size (diameter) of the sensor 17 is a, it is preferable to move the sensor 17 in a direction (second direction) such that the angle θ it makes with the periodic direction of the polishing marks (first direction) satisfies the following equation (9).

[0047]

number

[0048] As a result, the sensor 17 detects a light intensity distribution as shown in Figure 7(c), that is, a light intensity distribution that includes the light intensity at the imaging position of the aperture 31 of the measurement pattern 14 and the light intensity of the flare described above (a light intensity distribution that does not include only diffracted light).

[0049] Then, the control unit CU calculates the difference between the light intensity distribution shown in Figure 7(b) (first light intensity distribution for the first direction) and the light intensity distribution shown in Figure 7(b) (second light intensity distribution for the second direction). As a result, as shown in Figure 7(d), a light intensity distribution is obtained in which the effects of flares other than diffracted light are removed (light intensity distribution including only diffracted light), and information about the diffracted light can be obtained based on this light intensity distribution.

[0050] Next, referring to Figure 8, the process of adjusting the projection optical system 15 using the measurement process described above (adjustment process) will be explained. This adjustment process evaluates the effect of diffracted light caused by periodic polishing marks (structures) present on the surfaces of the optical elements constituting the projection optical system 15 during the manufacturing process using the exposure apparatus 1. If there is an effect of diffracted light, the optical element causing it is identified and improved. In this embodiment, the periodic direction (first direction) and frequency of the periodic polishing marks (structures) present on the surfaces of the multiple optical elements 15a, 15b, and 15c constituting the projection optical system 15 are assumed to be known. Furthermore, the periodic directions of the periodic polishing marks present on the surfaces of each of the optical elements 15a, 15b, and 15c may be different. A specific example of this is a large reflective optical element (for example, a concave mirror) used in the projection optical system 15. Such large reflective optical elements are often polished periodically in the same direction to improve the surface accuracy of their surfaces, and the periodic direction of the polishing marks is often known.

[0051] Referring to Figure 8, in S801, the light intensity (light quantity) of the normal light at the image plane of the projection optical system 15 is adjusted so that it is the light intensity required for the manufacturing process.

[0052] In S802, the light from the measurement pattern 14 is detected via the projection optical system 15 to form a light intensity distribution on the image plane of the projection optical system 15. Specifically, within the image plane of the projection optical system 15, the light intensity distribution for evaluating the first optical element 15a (hereinafter referred to as the "first optical element") is detected by moving it in the same direction as the periodic direction of the polishing marks on its surface. Similarly, within the image plane of the projection optical system 15, the light intensity distribution for evaluating the second optical element is detected by moving it in the same direction as the periodic direction of the polishing marks on its surface. Likewise, within the image plane of the projection optical system 15, the light intensity distribution for evaluating the third optical element is detected by moving it in the same direction as the periodic direction of the polishing marks on its surface.

[0053] In S803, it is determined whether the intensity of the diffracted light included in the light intensity distribution for evaluating the first optical element detected in S802 exceeds the acceptable range. Since the intensity of the diffracted light depends on the intensity of the normal light and the size of the polishing marks (structure), the intensity of the problematic diffracted light is estimated from the intensity of the normal light in the manufacturing process, and the acceptable range is set accordingly. If the intensity of the diffracted light included in the light intensity distribution for evaluating the first optical element exceeds the acceptable range, the first optical element is replaced in S804. On the other hand, if the intensity of the diffracted light included in the light intensity distribution for evaluating the first optical element does not exceed the acceptable range, the process proceeds to S805.

[0054] In S805, it is determined whether the light intensity of the diffracted light included in the light intensity distribution for evaluating the second optical element detected in S802 exceeds the acceptable range. If the light intensity of the diffracted light included in the light intensity distribution for evaluating the second optical element exceeds the acceptable range, the second optical element is replaced in S806. On the other hand, if the light intensity of the diffracted light included in the light intensity distribution for evaluating the second optical element does not exceed the acceptable range, the process proceeds to S807.

[0055] In S807, it is determined whether the light intensity of the diffracted light included in the light intensity distribution for evaluating the third optical element detected in S802 exceeds the acceptable range. If the light intensity of the diffracted light included in the light intensity distribution for evaluating the third optical element exceeds the acceptable range, the third optical element is replaced in S808. On the other hand, if the light intensity of the diffracted light included in the light intensity distribution for evaluating the third optical element does not exceed the acceptable range, the adjustment process is terminated.

[0056] As described above, in this embodiment, the adjustment process (adjustment method) for adjusting the projection optical system 15 comprises the first and second steps (S802) as measurement processes, the third step (S803, S805, S807), and the fourth step (S804, S806, S807). In the third step, based on information regarding diffracted light generated in the projection optical system 15 due to periodic polishing marks on the surface of the optical elements constituting the projection optical system 15, the optical elements constituting the projection optical system 15 that have polishing marks on their surface are identified. Note that an optical element with polishing marks on its surface means an optical element whose diffracted light intensity exceeds an acceptable range. In the fourth step, the optical element with polishing marks on its surface identified in the third step is replaced.

[0057] According to the adjustment process in this embodiment, the projection optical system 15 can be adjusted so as to improve the effect of diffracted light caused by periodic polishing marks (structures) on the surface of the optical elements constituting the projection optical system 15. Furthermore, in the exposure apparatus 1, the effect of diffracted light (ghosting) generated in the projection optical system 15 is reduced, enabling accurate transfer of the pattern from the pattern transfer master plate. Note that the adjustment process for adjusting the projection optical system 15 in this embodiment also includes adjustments made during the manufacturing (assembly) of the projection optical system 15 and during the manufacturing (assembly) of the exposure apparatus 1.

[0058] The method for manufacturing articles in the embodiments of the present invention is suitable for manufacturing articles such as flat panel displays, liquid crystal display elements, semiconductor elements, and MEMS. This manufacturing method includes the steps of: exposing a substrate coated with a photosensitive agent using the exposure apparatus 1 described above to obtain an exposed substrate (exposure step); and developing the exposed photosensitive agent to obtain a developed substrate (development step). Furthermore, an etching step or ion implantation step is performed on the substrate using the pattern of the developed photosensitive agent as a mask to form a circuit pattern on the substrate. These exposure, development, etching, and other steps are repeated to form a circuit pattern consisting of multiple layers on the substrate. In a subsequent step, dicing (processing) is performed on the substrate on which the circuit pattern has been formed, followed by chip mounting, bonding, and inspection steps. This manufacturing method may also include other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, resist peeling, etc.). The method for manufacturing articles in this embodiment is advantageous compared to conventional methods in at least one of the performance, quality, productivity, and production cost of the articles.

[0059] The disclosures herein include the following measurement methods, adjustment methods, exposure apparatuses, and methods for manufacturing articles.

[0060] (Item 1) A measurement method for measuring diffracted light generated in an optical system under test, A first step of detecting the light intensity distribution formed on the image plane of the optical system under test by light from a measurement pattern including an aperture and a shielding portion surrounding the aperture, which is arranged on the object surface of the optical system under test, via the optical system under test. A second step involves obtaining information about diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical elements constituting the optical system under test, based on the light intensity distribution detected in the first step, A measurement method characterized by having the following features.

[0061] (Item 2) The first step described above is, A step of detecting a first light intensity distribution in the same first direction as the periodic direction of the polishing marks present on the surface of the optical element within the image plane of the optical system under test, A step of detecting a second light intensity distribution in a second direction intersecting the first direction within the image plane of the optical system under test, Includes, The measurement method according to item 1, characterized in that, in the second step, information regarding the diffracted light is obtained based on the difference between the first light intensity distribution and the second light intensity distribution.

[0062] (Item 3) The measurement method according to item 2, characterized in that the second direction includes the imaging position of the aperture and does not include the imaging position of the diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical element.

[0063] (Item 4) In the first step described above, The first light intensity distribution is detected by moving a sensor that detects light from the measurement pattern via the optical system under test in the first direction within the image plane of the optical system under test, The sensor is moved in the second direction within the image plane of the optical system under test to detect the second light intensity distribution. The measurement method described in item 2, characterized by the following:

[0064] (Item 5) The measurement method according to item 1, characterized in that, in the first step, the light intensity distribution is detected by moving a sensor that detects light from the measurement pattern via the optical system under test within the image plane of the optical system under test.

[0065] (Item 6) The measurement method according to item 5, characterized in that, in the first step, the sensor is moved in the same direction as the periodic direction of the polishing marks present on the surface of the optical element within the image plane of the optical system under test.

[0066] (Item 7) The measurement method according to any one of items 1 to 6, characterized in that, as the light intensity distribution, a light intensity distribution is detected in which the light intensity at the imaging position of the aperture and the light intensity at the imaging position of the diffracted light generated in the optical system due to periodic polishing marks present on the surface of the optical element are separated, the aperture diameter of the aperture and the distance between the aperture end of the aperture and the outer end of the shielding portion are defined by the frequency of the polishing marks present on the surface of the optical element.

[0067] (Item 8) The aperture diameter R of the opening is such that, λ is the wavelength of the light illuminating the measurement pattern, NA is the numerical aperture of the optical system under test, and f is the specific frequency of the wavefront aberration of the optical system under test. The measurement method described in item 7, characterized by satisfying the requirements of JPEG0007836224000010.jpg1625.

[0068] (Item 9) The distance S between the opening end of the opening and the outer end of the shielding portion is such that λ is the wavelength of the light illuminating the measurement pattern, NA is the numerical aperture of the optical system under test, and f is the specific frequency of the wavefront aberration of the optical system under test. The measurement method described in item 7, characterized by satisfying the requirements of JPEG0007836224000011.jpg1625.

[0069] (Item 10) The specific frequency f of the wavefront aberration of the optical system under test is given by, where 1 is the pupil diameter of the optical system under test, P is the frequency of the polishing marks on the surface of the optical element, and D is the diameter of the light beam at the optical element. A measurement method according to any one of items 1 to 9, characterized by being represented as JPEG0007836224000012.jpg1422.

[0070] (Item 11) The measurement method according to any one of items 1 to 10, characterized in that the information relating to the diffracted light includes information indicating the position and light intensity of the diffracted light on the image plane of the optical system under test.

[0071] (Item 12) The measurement method according to any one of items 1 to 11, characterized in that the optical system under test includes a projection optical system used in an exposure apparatus for transferring the pattern of a master plate onto a substrate, for projecting the pattern of the master plate onto the substrate.

[0072] (Item 13) A method for adjusting the optical system under test, A first step of detecting the light intensity distribution formed on the image plane of the optical system under test by light from a measurement pattern including an aperture and a shielding portion surrounding the aperture, which is arranged on the object surface of the optical system under test, via the optical system under test. A second step involves obtaining information about diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical elements constituting the optical system under test, based on the light intensity distribution detected in the first step, A third step involves identifying, based on the information obtained in the second step, the optical elements constituting the optical system under test that have polishing marks on their surface, A fourth step involves replacing the optical element on which the polishing marks identified in the third step are present on the surface, A method of adjustment characterized by having the following features.

[0073] (Item 14) The information relating to the diffracted light includes information indicating the position and light intensity of the diffracted light on the image plane of the optical system under test, In the third step, based on the position and light intensity of the diffracted light, the optical element on which the polishing marks are present on the surface is identified. The adjustment method described in item 13, characterized by the features described herein.

[0074] (Item 15) Having a projection optical system adjusted by the adjustment method described in item 13 or 14, The projection optical system is an exposure apparatus characterized by transferring the pattern of the original plate onto a substrate.

[0075] (Item 16) An exposure step in which a substrate is exposed using the exposure apparatus described in item 15 to obtain an exposed substrate, The process includes developing the aforementioned photopolymer substrate to obtain a developed substrate, A method for manufacturing an article, characterized by manufacturing an article from the aforementioned developing substrate.

[0076] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0077] 1: Exposure device 12: Measurement master plate 14: Measurement pattern 15: Projection optical system 15a, 15b, 15c: Optical elements 17: Sensor CU: Control unit

Claims

1. A measurement method for measuring diffracted light generated in an optical system under test, A first step of detecting the light intensity distribution formed on the image plane of the optical system being tested by light from a measurement pattern, which includes an aperture and a shielding portion surrounding the aperture, located on the object surface of the optical system being tested, via the optical system being tested. A second step involves obtaining information about diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical elements constituting the optical system under test, based on the light intensity distribution detected in the first step, A measurement method characterized by having the following features.

2. The first step is, A step of detecting a first light intensity distribution in the same first direction as the periodic direction of the polishing marks present on the surface of the optical element within the image plane of the optical system under test, A step of detecting a second light intensity distribution in a second direction intersecting the first direction within the image plane of the optical system under test, Includes, The measurement method according to claim 1, characterized in that, in the second step, information regarding the diffracted light is obtained based on the difference between the first light intensity distribution and the second light intensity distribution.

3. The measurement method according to claim 2, characterized in that the second direction includes the imaging position of the aperture and does not include the imaging position of the diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical element.

4. In the first step described above, The first light intensity distribution is detected by moving a sensor that detects light from the measurement pattern via the optical system under test in the first direction within the image plane of the optical system under test, The sensor is moved in the second direction within the image plane of the optical system under test to detect the second light intensity distribution. The measurement method according to feature 2.

5. The measurement method according to claim 1, characterized in that, in the first step, the light intensity distribution is detected by moving a sensor that detects light from the measurement pattern via the optical system under test within the image plane of the optical system under test.

6. The measurement method according to claim 5, characterized in that, in the first step, the sensor is moved in the same direction as the periodic direction of the polishing marks present on the surface of the optical element within the image plane of the optical system under test.

7. The measurement method according to claim 1, characterized in that, as the light intensity distribution, a light intensity distribution is detected in which the light intensity at the imaging position of the aperture and the light intensity at the imaging position of the diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical element are separated, the aperture diameter of the aperture and the distance between the aperture end of the aperture and the outer end of the shielding portion are defined by the frequency of the polishing marks present on the surface of the optical element.

8. The aperture diameter R of the opening is such that, λ is the wavelength of the light illuminating the measurement pattern, NA is the numerical aperture of the optical system under test, and f is the specific frequency of the wavefront aberration of the optical system under test. The measurement method according to claim 7, characterized in that it satisfies the requirements.

9. The distance S between the opening end of the opening and the outer end of the shielding portion is such that λ is the wavelength of the light illuminating the measurement pattern, NA is the numerical aperture of the optical system under test, and f is the specific frequency of the wavefront aberration of the optical system under test. The measurement method according to claim 7, characterized in that it satisfies the requirements.

10. The specific frequency f of the wavefront aberration of the optical system under test is given by, where 1 is the pupil diameter of the optical system under test, P is the frequency of the polishing marks on the surface of the optical element, and D is the diameter of the light beam at the optical element. The measurement method according to claim 1, characterized by being represented as follows.

11. The measurement method according to claim 1, characterized in that the information relating to the diffracted light includes information indicating the position and light intensity of the diffracted light on the image plane of the optical system under test.

12. The measurement method according to claim 1, characterized in that the optical system under test includes a projection optical system used in an exposure apparatus for transferring the pattern of a master plate onto a substrate, which projects the pattern of the master plate onto the substrate.

13. A method for adjusting the optical system under test, A first step of detecting the light intensity distribution formed on the image plane of the optical system being tested by light from a measurement pattern, which includes an aperture and a shielding portion surrounding the aperture, located on the object surface of the optical system being tested, via the optical system being tested. A second step involves obtaining information about diffracted light generated in the optical system under test due to periodic polishing marks present on the surface of the optical elements constituting the optical system under test, based on the light intensity distribution detected in the first step, A third step involves identifying, based on the information obtained in the second step, the optical elements constituting the optical system under test that have polishing marks on their surface, A fourth step involves replacing the optical element on which the polishing marks identified in the third step are present on the surface, A method of adjustment characterized by having the following features.

14. The information relating to the diffracted light includes information indicating the position and light intensity of the diffracted light on the image plane of the optical system under test, In the third step, based on the position and light intensity of the diffracted light, the optical element on which the polishing marks are present on the surface is identified. The adjustment method according to feature 13.

15. Having a projection optical system adjusted by the adjustment method described in claim 13 or 14, The projection optical system is an exposure apparatus characterized by transferring the pattern of the original plate onto a substrate.

16. An exposure step of exposing a substrate using the exposure apparatus described in claim 15 to obtain an exposed substrate, The process includes developing the aforementioned photopolymer substrate to obtain a developed substrate, A method for manufacturing an article, characterized by manufacturing an article from the aforementioned developing substrate.

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