Luminescent dye and detection method using luminescent dye

Abstract

In the present invention, a complex includes a group 13 element and retains a luminescent color corresponding to the maximum temperature in a temperature change process as a fixed color even after the temperature change.

Description

Luminescent dye and detection method using the same

[0001] Various aspects and embodiments of the present disclosure relate to luminescent dyes and detection methods using luminescent dyes.

[0002] The following non-patent document 1 discloses that "general organic luminescent dyes lose most of their luminescent properties in solids. In an aggregated state, it is thought that strong intermolecular interactions occur in the ground state and excited state, causing quenching of luminescence. This phenomenon is called concentration quenching."

[0003] Furthermore, Non-Patent Document 1 listed below discloses that "AIE is a phenomenon that Tang et al. reported in 2001 to occur in pentaphenylsilole. This molecule does not exhibit luminescence in solution, but exhibits increased luminescence intensity in aggregation or in the solid state, which is the opposite behavior to conventional organic dyes. The reason for this is explained as follows: in solution, molecular motion promotes decay of the excited state, but in the aggregated state, the deactivation process associated with this molecular motion is inhibited, resulting in luminescence."

[0004] Furthermore, Patent Document 1 below discloses that "preferably, in the alignment device of the second invention, the substance formed on the upper surface of the recording medium is a substance that emits fluorescence or phosphorescence when excited by light of the exposure wavelength."

[0005] Patent No. 2629709

[0006] Issei Tanaka and two others, "Design of stimuli-responsive luminescent materials based on flexible boron element blocks," Journal of the Imaging Society of Japan, 2019, Vol. 58, No. 1, pp. 81-92

[0007] The present disclosure relates to observing the temperature conditions to which materials used in the manufacturing process have been exposed.

[0008] One aspect of the present disclosure is a complex containing a Group 13 element, which maintains an emission color corresponding to a maximum temperature during a temperature change process as a fixed color even after the temperature change.

[0009] According to various aspects and embodiments of the present disclosure, it is possible to observe the temperature conditions to which materials used in a manufacturing process have been exposed.

[0010] FIG. 1 is a diagram showing an example of the distribution of emission spectra for each temperature. FIG. 2 is a diagram showing an example of the temperature change in the ratio of the emission intensity at a wavelength of 592 nm to the emission intensity at a wavelength of 510 nm. FIG. 3 is a diagram showing an example of a production process for compound (1). FIG. 4 is a flowchart showing an example of an alignment method. FIG. 5 is a schematic diagram showing an example of the configuration of an exposure apparatus. FIG. 6A is a plan view showing an example of a substrate near a marker. FIG. 6B is a cross-sectional view showing an example of a substrate near a marker. FIG. 7A is a plan view showing an example of a substrate near a marker after a fluorescent image has been formed. FIG. 7B is a cross-sectional view showing an example of a substrate near a marker after a fluorescent image has been formed. FIG. 8 is a diagram showing an example of a marker arrangement. FIG. 9 is a diagram showing an example of a marker arrangement. FIG. 10 is a flowchart showing an example of a surface observation method. FIG. 11 is a diagram showing an example of the procedure for the surface observation method. FIG. 12 is a diagram showing an example of the procedure for the surface observation method. FIG. 13 is a diagram showing an example of the procedure for the surface observation method. FIG. 14 is a diagram showing an example of the procedure for the surface observation method. FIG. 15 is a diagram showing an example of the relationship between the thickness of a photoresist and the exposure dose. Fig. 16 is a diagram showing another example of the state of the photoresist Fig. 17 is a diagram showing an example of the hardware configuration of a computer.

[0011] The technology of the embodiments will be described in detail below with reference to the drawings. Note that the technology disclosed is not limited to the following embodiments.

[0012] Temperature control is important in the semiconductor manufacturing process. Therefore, it is important to observe the temperature conditions to which the materials used in the manufacturing process are exposed. However, it is difficult to measure the temperatures of the materials used in the manufacturing process during semiconductor manufacturing.

[0013] Therefore, the present disclosure provides a technique that can observe the temperature conditions to which materials used in the manufacturing process have been exposed.

[0014] First Embodiment The inventors of the present application have found that compound (1) having the following structure has the property of maintaining the luminescent color corresponding to the maximum temperature during a temperature change process as a fixed color even after the temperature change.

[0015] Compound (1) is a complex containing a Group 13 element. The Group 13 element contained in compound (1) is, for example, boron. Compound (1) also has a pyridyl enolate ligand as an organic skeleton. Compound (1) is, for example, a dimethylboron complex having two methyl groups.

[0016] Furthermore, when compound (1) is irradiated with light containing UV light (ultraviolet light), the intensity distribution of the emission wavelength (distribution of the emission spectrum) changes with temperature, as shown in Fig. 1. Fig. 1 is a diagram illustrating an example of the distribution of the emission spectrum for each temperature.

[0017] 1 , when compound (1) is irradiated with light containing UV light at a relatively low temperature (e.g., 83 K), the emission spectrum distribution of compound (1) shows a high emission intensity in the green wavelength range (490 to 550 nm). Therefore, when compound (1) is irradiated with light containing UV light at a relatively low temperature, compound (1) emits green light.

[0018] On the other hand, when irradiated with light containing UV light at a relatively high temperature (for example, 423 K), the emission spectrum of compound (1) shows a high emission intensity at orange wavelengths (590 to 640 nm). Therefore, when irradiated with light containing UV light at a relatively high temperature, compound (1) emits orange light.

[0019] In the emission spectrum, the ratio of the emission intensity at a wavelength of 510 nm in the green wavelength band to the emission intensity at a wavelength of 592 nm in the orange wavelength band changes, for example, as shown in FIG. 2 when irradiated with light including UV light. 510 represents the intensity of light emitted at a wavelength of 510 nm, and I 592 represents the emission intensity at a wavelength of 592 nm.

[0020] As illustrated in FIG. 2, the higher the temperature of compound (1), the higher the luminescence intensity I​510 Emission intensity I 592 The ratio ln(I 592 / I 510 ) becomes larger, and the lower the temperature of compound (1), the higher the luminescence intensity I 510 Emission intensity I 592 The ratio ln(I 592 / I 510 ) becomes smaller.

[0021] Thus, when irradiated with light including UV light, there is a correlation between the distribution of the emission spectrum of compound (1) and the temperature of compound (1). In particular, the emission intensity I 510 Emission intensity I 592 The ratio ln(I 592 / I 510 ) shows a strong correlation with the temperature of compound (1). 510 Emission intensity I 592 The ratio ln(I 592 / I 510 ) can be used to estimate the temperature of compound (1).

[0022] The change in the emission color of compound (1) occurs due to rearrangement of the methyl group. When compound (1) is irradiated with light including UV light and the temperature of compound (1) increases, the methyl group of compound (1) rearranges, for example, as shown in the following compounds (1-1) and (1-2).

[0023] Compound (1-1) emits orange light. When irradiated with light including UV light, the amount of compound (1-1) increases as the temperature rises. As a result, the color of the light emitted by the entire compound changes from green to orange as the temperature rises. Note that the amount of compound (1-2) is so small that it has almost no effect on the overall color of the light emitted.

[0024] ​The change from compound (1) to compound (1-1) and compound (1-2) depends on the temperature. The higher the temperature, the more the change from compound (1) to compound (1-1) and compound (1-2) increases. Since the amount of change from compound (1) to compound (1-2) is small, the luminescent color of the entire compound is determined by the ratio of compound (1) to compound (1-1).

[0025] Furthermore, the change from compound (1) to compound (1-1) and compound (1-2) is a unidirectional, irreversible change. Therefore, even if the temperature is lowered while the compound is irradiated with light including UV light, compound (1-1) and compound (1-2) do not change to compound (1). Therefore, the compound as a whole will be fixed at the luminescent color corresponding to the highest temperature to which the compound is exposed.

[0026] Furthermore, the transformation of compound (1) into compound (1-1) and compound (1-2) does not occur by a temperature increase alone, but requires irradiation with light including UV light. Therefore, in the absence of irradiation with light including UV light, even if the temperature of compound (1) increases, the transformation of compound (1) into compound (1-1) and compound (1-2) does not occur.

[0027] Furthermore, by mixing a material containing compound (1) with a material used for substrate processing or by disposing it in a component of a substrate processing apparatus, the maximum substrate temperature during processing performed under an environment in which light including UV light is irradiated can be confirmed after the substrate processing is completed. Examples of materials used for substrate processing include photoresists. Examples of apparatus for processing substrates include film formation apparatuses, exposure apparatuses, etching apparatuses, cleaning apparatuses, etc.

[0028] In this way, a surface observation method is realized in which a material containing compound (1) is prepared on the surface of a component, light containing UV light is irradiated onto the material containing compound (1), and a fluorescent image is obtained. This makes it possible to confirm the maximum temperature of the component in a treatment performed in an environment where light containing UV light is irradiated after the treatment is completed. The step of preparing a material containing compound (1) on the surface of a component is an example of step a1). Furthermore, the step of irradiating light containing UV light onto the material containing compound (1) and obtaining a fluorescent image is an example of step a2).

[0029] In order to observe the luminescent color of the above-mentioned compound, it is necessary to irradiate the compound with light containing UV light. However, if the compound is irradiated with light containing UV light at a high temperature, the luminescent color will change to a color corresponding to the temperature at that time. Therefore, in order to later observe the maximum temperature to which the compound was exposed, it is necessary to irradiate the compound with light containing UV light at a sufficiently low temperature.

[0030] However, if the irradiation time of light including weak UV light is short, the emission color of the compound can be observed without causing a change from compound (1) to compound (1-1) or compound (1-2), even in a high-temperature environment. In an experiment, when a sample containing the compound was irradiated with light from a UV lamp (wavelength 365 nm, output 8 W) from a position 20 cm or more away from the sample for an irradiation time of 5 seconds or less, the emission color of the compound could be observed without causing a change in the emission color of the compound.

[0031] [Method for producing compound (1)] Figure 3 shows an example of a process for producing compound (1). In the method for producing compound (1), first, compound (a) (5-bromo-2-methylpyridine) shown below and LDA (lithium diisopropylamide) are mixed in THF (tetrahydrofuran) as a solvent, and reacted at -78°C for 3 hours.

[0032] Then, compound (b) (N-methoxy-N-methylbenzamide) shown below is added and reacted for an additional 3 hours at a temperature between −78° C. and room temperature to obtain compound (c) (2-(5-bromopyridin-2-yl)-1-phenylethan-1-one) shown below. Compound (c) is an example of a pyridyl enolate ligand.​

[0033] Then, compound (c), EtN (triethylamine), and FB--OEt (boron trifluoride-diethyl ether complex) are mixed in dichloromethane (DCM) as a solvent. The mixture is refluxed overnight to obtain compound (d) (7-bromo-1,1-difluoro-3-phenyl-1H-1λ) shown below. 4 , 9λ 4 -pyrido[1,2-c][1,3,2]oxazaborinine) is obtained. The structure of compound (d) was obtained by cleaving the compound (d) with deuterated chloroform (CDCl3). 1 The identity was confirmed by H NMR (nuclear magnetic resonance) and HRMS (mass spectrometry).

[0034] Next, compound (d) and compound (e) shown below (4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane) are mixed in a toluene / water solvent using Pd(dppf)Cl.CHCl ([1,1-bis(diphenylphosphino)ferrocene]dichloropalladium(II)) and KCO (potassium carbonate) as catalysts.

[0035] The mixture was then reacted at 80° C. overnight to obtain the compound (f) (1,1-difluoro-3,7-diphenyl-1H-1λ) shown below. 4 , 9λ 4 -pyrido[1,2-c][1,3,2]oxazaborinine) is obtained. Compounds (d) and (f) are examples of difluoro complexes. The structure of compound (f) can be obtained by the cleavage of deuterated chloroform. 1 H NMR, 11 B NMR, and 13 Confirmed by C NMR.

[0036] Then, compound (f) and MeMgBr (methyl magnesium bromide) are mixed in EtO (diethyl ether) as a solvent and reacted at a temperature between 0°C and room temperature for 3 hours to obtain compound (1). The structure of compound (1) can be obtained by the reaction using CDCl (deuterated dichloromethane).​​​​1 H NMR, 11 B NMR, 13 This was confirmed by C NMR and SCXRD (single crystal X-ray diffraction).

[0037] Since compound (1) exhibits similar properties in both solution and solid form, it may be mixed into materials such as photoresist and silicone rubber.

[0038] In addition to the above-mentioned compound (1), the following compounds (2) to (5) can be mentioned as compounds having the property of maintaining the luminescent color corresponding to the maximum temperature during the temperature change process as a fixed color even after the temperature change.

[0039] The first embodiment has been described above. As described above, the complex in this embodiment is a complex containing a Group 13 element, and the luminescent color corresponding to the maximum temperature during a temperature change process is maintained as a fixed color even after the temperature change. By using such a complex, it is possible to observe the temperature conditions to which materials used in a manufacturing process have been exposed.

[0040] The Group 13 element contained in the complex may be boron, and the complex has a pyridyl enolate ligand as an organic skeleton. The complex may also be a dimethylboron complex having two methyl groups. The complex may also be produced by reacting a difluoro complex obtained through a reaction between a pyridyl enolate ligand and a boron trifluoride-diethyl ether complex with methylmagnesium bromide. Such complexes may have the structures shown in the above-described compounds (1) to (5).

[0041] ​The surface observation method of this embodiment includes steps a1) and a2). In step a1), a material is prepared that includes a complex containing a Group 13 element, which maintains a fixed color of light emitted from the material at the highest temperature during a temperature change process even after the temperature change. In step a2), the material is irradiated with light, and a fluorescent image is acquired. This makes it possible to observe the temperature conditions to which the material used in the manufacturing process was exposed.

[0042] Second Embodiment In a second embodiment, alignment in an exposure apparatus is performed using the compound exemplified in the first embodiment. Fig. 4 is a flowchart showing an example of an alignment method. The alignment method exemplified in Fig. 4 is performed in an environment where light including UV light is not irradiated onto the substrate W, unless otherwise specified. Each process in the flowchart exemplified in Fig. 4 is realized by, for example, a computer 90 exemplified in Fig. 17 controlling each part of the exposure apparatus.

[0043] The alignment method illustrated in Fig. 4 is realized, for example, by an exposure apparatus 10 illustrated in Fig. 5. The exposure apparatus 10 includes a light source 11, a projection optical system 13, a moving stage 14, and a sensor 15. The light source 11 irradiates a reticle 12 with light including UV light. The projection optical system 13 forms an image of the reticle 12 projected by the light source 11 onto a substrate W placed on the moving stage 14. The moving stage 14 incorporates a temperature control mechanism for controlling the temperature of the substrate W. The sensor 15 detects a fluorescent image formed on the substrate W. The reticle 12 is an example of a first flat plate, and the substrate W is an example of a second flat plate.

[0044] 6A and 6B, the substrate W has an underlayer 20, a photoresist 21 laminated on the underlayer 20, and a marker 22 formed on the underlayer 20. The marker 22 is formed on the upper surface of the underlayer 20 using, for example, copper. The marker 22 can be observed from above through the photoresist 21. The compound (1) exemplified in the first embodiment is mixed into the photoresist 21.

[0045] First, the substrate W is placed on the movable stage 14, and the temperature of the substrate W is controlled by a temperature control mechanism incorporated in the movable stage 14 so that the temperature of the substrate W becomes a first temperature (step S10). The first temperature is, for example, −20° C. Step S10 is an example of step b4).

[0046] Next, the substrate W is moved by the moving stage 14 so that the marker 22 on the substrate W is positioned below the sensor 15. Then, the sensor 15 acquires a first emission spectrum at each position of the photoresist 21 (step S11). Step S11 is an example of process b5). The sensor 15 has a camera and a light source that irradiates light including UV light. In step S11, the light source irradiates the substrate W with light including UV light, and the camera acquires the emission spectrum of the light emitted by the photoresist 21 of the substrate W as the first emission spectrum.

[0047] Next, the temperature of the substrate W is controlled by a temperature control mechanism incorporated in the moving stage 14 so that the temperature of the substrate W becomes a second temperature higher than the first temperature (step S12). The second temperature is, for example, 20° C. Step S12 is an example of step b6).

[0048] Next, the substrate W is moved by the moving stage 14 so that the marker 22 on the substrate W is positioned below the projection optical system 13. Then, the pattern of the marker provided on the reticle 12 is projected onto the position of the marker 22 on the substrate W using light emitted from the light source 11 (step S13). Step S13 is an example of step b1).

[0049] 7A and 7B, light including UV light is irradiated onto a region 23 of the photoresist 21 that corresponds to the shape of the marker on the reticle 12. Because the compound (1) exemplified in the first embodiment is mixed into the photoresist 21, the emitted light color of the region 23 changes to an emitted light color corresponding to the second temperature. Then, the light irradiation by the light source 11 is stopped.

[0050] Next, the temperature of the substrate W is controlled by the temperature control mechanism incorporated in the moving stage 14 so that the temperature of the substrate W becomes a third temperature lower than the second temperature (step S14). The third temperature is, for example, −20° C.

[0051] Here, the emission spectrum of the region 23 irradiated with the light including UV light in step S13 is fixed at an emission color corresponding to the second temperature higher than the third temperature. Therefore, even if the light including UV light is irradiated to the photoresist 21 at the third temperature, the emission spectrum of the region 23 irradiated with the light including UV light in step S13 is the same as the emission spectrum at the second temperature.

[0052] Next, the substrate W is moved by the moving stage 14 so that the marker 22 on the substrate W is positioned under the sensor 15. The sensor 15 then acquires an emission spectrum at each position on the photoresist 21. Then, based on a second emission spectrum emitted from a region 23 of the marker pattern projected onto the photoresist 21, a fluorescent image corresponding to the projected marker pattern is acquired (step S15). Step S15 is an example of step b2).

[0053] Next, it is determined whether the misalignment between the marker 22 and the fluorescent image is within an allowable range (step S16). If the misalignment between the marker 22 and the fluorescent image is within the allowable range (step S16: Yes), exposure of the circuit pattern onto the substrate W is started (step S18), and the alignment method shown in this flowchart is completed.

[0054] On the other hand, if the deviation between the marker 22 and the fluorescent image is outside the allowable range (step S16: No), the position of the substrate W is adjusted by the moving stage 14 according to the direction and magnitude of the deviation between the marker 22 and the fluorescent image (step S17). Step S17 is an example of process b3). Then, the process shown in step S18 is executed.

[0055] 4, it is possible to correct the misalignment between the reticle 12 and the substrate W without actually performing exposure and development, thereby reducing waste of the substrate W and shortening the time required to correct the misalignment.

[0056] It is also possible to detect misalignment between the reticle 12 and the substrate W without performing exposure and development by measuring the area 23 onto which the marker pattern is projected using an external device such as an AFM (atomic force microscope) by utilizing the volume expansion of the photoresist 21 due to exposure. However, this requires time to transport the substrate W to a device external to the exposure apparatus 10. In contrast, in this embodiment, misalignment can be corrected within the exposure apparatus 10, so the time required to correct the misalignment can be reduced.

[0057] The second embodiment has been described above. As described above, the alignment method of this embodiment includes steps b1), b2), and b3). In step b1), a pattern on a first plate (reticle 12) is projected onto a second plate (substrate W) via a projection optical system (projection optical system 13) using light including ultraviolet light. The second plate includes an underlayer (underlayer 20) on which markers (markers 22) are formed, and a material (photoresist 21) formed on the underlayer and containing a complex containing a Group 13 element, the material maintaining a fixed color of light emitted from a temperature corresponding to the highest temperature during a temperature change process even after the temperature change. In step b2), a fluorescent image of the pattern projected onto the material is acquired. In step b3), the position of the second plate is adjusted based on the positional relationship between the markers and the fluorescent image. This reduces waste of substrate W and shortens the time required to correct misalignment.

[0058] The alignment method according to the second embodiment includes steps b4), b5), and b6). Step b4) is performed before step b1), in which the temperature of the second plate is set to a first temperature. Step b5) is performed after step b4) but before step b1), in which a first emission spectrum emitted by the material is obtained by irradiating the second plate with light including ultraviolet light. Step b6) is performed after step b5) but before step b1), in which the temperature of the second plate is set to a second temperature higher than the first temperature. Step b1) is performed when the temperature of the second plate is at the second temperature, and step b2) identifies a region of the fluorescent image (region 23) based on a second emission spectrum emitted by the fluorescent image, the second emission spectrum being different from the first emission spectrum. This allows the region of the fluorescent image of the pattern projected onto the material to be identified with high accuracy.

[0059] In the second embodiment, in step b2), the temperature of the second plate is set to a third temperature that is lower than the second temperature, so that even when the second plate is irradiated with light including ultraviolet light, the luminescent color of the complex contained in the material does not change, and the luminescent color of the complex contained in the material can be observed.

[0060] It is also possible to form a plurality of markers 22 on the base layer 20, and after alignment is performed using one marker 22, further alignment is performed using another marker 22. Specifically, after the position of the second flat plate is adjusted in step b3), steps b1) to b3) may be performed using another marker. This can further improve the accuracy of alignment.

[0061] 8 and 9, the surface of the substrate W (second flat plate) may be divided into a plurality of predetermined small regions 25, and steps b1) to b3) may be performed for each of the plurality of small regions 25 on the substrate W. Each small region 25 is, for example, the region of one semiconductor chip (so-called DIE) formed on the substrate W. This allows accurate alignment of each small region 25.

[0062] Furthermore, multiple markers 22 may be formed in the base layer 20 of each small region 25, as shown in Figures 8 and 9, for example. In the example of Figure 9, multiple marker placement regions 27 are provided within the small region 25, and multiple markers 22 are placed within the marker placement regions 27. Then, for each small region 25, alignment may be performed using one marker 22, and then further alignment may be performed using another marker 22. Specifically, for each small region, after the position of the second flat plate is adjusted in step b3), steps b1) to b3) may be performed for another marker. This can further improve the accuracy of alignment for each small region 25.

[0063] Third Embodiment When photoresist residues remain in the opening regions of the patterned photoresist, the recesses formed by etching may not have the desired range or depth due to the residues. Therefore, in this embodiment, a photoresist containing the compound (1) exemplified in the first embodiment is patterned.

[0064] Then, the intensity of light emitted from compound (1) contained in the photoresist is measured for each predetermined region. If the measured light intensity exceeds the intensity of light from compound (1) estimated from the photoresist pattern to be formed in that region, it can be determined that more photoresist remains in that region than the amount of photoresist to be formed in that region. Therefore, by measuring the intensity of light emitted from compound (1) contained in the photoresist for each predetermined region, the amount of photoresist residue remaining in that region can be estimated.

[0065] [Surface Observation Method] Fig. 10 is a flowchart illustrating an example of a surface observation method. Each process in the flowchart illustrated in Fig. 10 is realized by, for example, a computer 90 illustrated in Fig. 17 controlling each device.

[0066] First, a photoresist containing compound (1) is formed on a substrate W (step S20). In step S20, as shown in Fig. 11, for example, an anti-reflection film 31 is formed on an underlayer 30, and a photoresist 32 containing compound (1) is formed on the anti-reflection film 31. The photoresist 32 is formed on the anti-reflection film 31 by, for example, spin coating.

[0067] In this embodiment, for example, the following compound (6) (methoxypropyl acetate) is used as the material of the photoresist 32. However, the material of the photoresist 32 is not limited to compound (6).

[0068] Next, the photoresist 32 is exposed and developed to form a predetermined pattern in the photoresist 32 (step S21). In step S21, the photoresist 32 is exposed to UV light from a KrF (krypton fluoride) light source or the like, for example, by irradiating the areas of the photoresist 32 to be removed along the predetermined pattern. The exposed portions of the photoresist 32 are dissolved and removed with a chemical solution. As a result, a pattern such as that shown in FIG. 12 is formed in the photoresist 32.

[0069] 12, residues 34 may remain in the openings 33 formed in the photoresist 32 due to insufficient exposure. If residues 34 remain in the openings 33, the quality of subsequent etching at the positions of the openings 33 may be reduced. Therefore, a process for removing residues 34 in the openings 33 is required.

[0070] ​Next, the entire substrate W is scanned using a camera module (step S22). In step S22, as shown in Fig. 13, for example, a camera module 40 having a plurality of cameras 41 and a plurality of illuminators 42 scans over the substrate W to obtain an image showing the surface condition of the substrate W. As shown in Fig. 14, for example, each of the cameras 41 and the illuminators 42 irradiates the surface of the substrate W with light including UV light from the illuminators 42 during the scanning process. As a result, an image (fluorescence image) showing the surface condition of the substrate W is obtained.

[0071] Next, it is determined whether or not residues 34 of photoresist 32 have been detected (step S23). In step S23, the surface of the substrate W is divided into a plurality of predetermined regions, and for each region, the intensity of light from compound (1) estimated from the photoresist pattern to be formed in that region (reference intensity) is determined in advance by experiment or the like. Then, based on an image (fluorescence image) of the surface of the substrate W, it is determined for each region whether the intensity of light detected from the image exceeds the reference intensity. If the intensity of light detected from the image for each region exceeds the reference intensity, it is determined that more photoresist 32 remains in that region than should remain, and that residues 34 are present.

[0072] In this embodiment, since the photoresist 32 contains the compound (1), the light intensity measured corresponds to the amount of the photoresist 32. Note that the photoresist 32 itself also emits fluorescence, but the intensity of the light emitted from the photoresist 32 is sufficiently smaller than the intensity of the light emitted by the compound (1). Therefore, by measuring the intensity of the light from the photoresist 32, the thickness of the photoresist 32 can be estimated.

[0073] Furthermore, compound (1) contained in photoresist 32 is a luminescent dye exhibiting CIE (crystal-induced luminescence), and therefore does not undergo concentration quenching even when aggregated within photoresist 32. Therefore, even if the concentration of compound (1) in photoresist 32 increases, concentration quenching does not occur, and fluorescence can be emitted with high luminescence intensity.

[0074] If no residue 34 is detected in the opening 33 of the photoresist 32 (step S23: No), the surface observation method shown in this flowchart ends. On the other hand, if residue 34 is detected in the opening 33 of the photoresist 32 (step S23: Yes), the area where the residue 34 is detected is photographed in detail (step S24), and the surface observation method shown in this flowchart ends.

[0075] In step S24, the detailed position of the residue 34 is identified, and exposure and development may be performed again at the position on the substrate W where the residue 34 was detected. In this case, the thickness of the residue 34 may be estimated from the difference between the reference emission intensity and the detected emission intensity in the region of the substrate W where the residue 34 was detected. That is, the thickness of the residue 34 remaining in the opening 33 may be determined based on the intensity of light emitted from each region in the fluorescent image.

[0076] Then, exposure may be performed again by irradiating the position on the substrate W where the residue 34 was detected with light of an exposure amount necessary to remove the residue 34 of the estimated thickness. That is, the residue 34 remaining in the opening 33 may be removed by irradiating the opening 33 where the residue 34 remains with light of an exposure amount necessary to remove the residue 34 of the determined thickness.

[0077] Fig. 15 is a diagram showing an example of the relationship between the thickness of the photoresist 32 and the exposure dose. Fig. 15 plots the thickness of the photoresist 32 remaining after development at each exposure dose when the exposure dose is changed for a photoresist 32 of a predetermined thickness. For example, from the experimental results shown in Fig. 15, it is possible to calculate the exposure dose required to remove the residue 34 relative to its thickness.

[0078] In addition, in this embodiment, the presence or absence of residue 34 is determined by comparing the reference emission intensity with the detected emission intensity in each region on the substrate W, but the disclosed technology is not limited to this. For example, as shown in Fig. 16 , the technology of this embodiment can also be applied to detecting pattern collapse of photoresist 32 after pattern formation.

[0079] For example, in region A in FIG. 16 , a portion of the photoresist 32 in region A has collapsed toward the outside of region A, resulting in a smaller amount of photoresist 32 than the design value. Therefore, in region A, the detected emission intensity is smaller than the reference emission intensity. On the other hand, in region B adjacent to region A, a portion of the photoresist 32 in region B has collapsed toward the inside of region B, resulting in a larger amount of photoresist 32 than the design value. Therefore, in region B, the detected emission intensity is larger than the reference emission intensity. In this way, by comparing the detected emission intensity with the reference emission intensity for a plurality of adjacent regions, it is also possible to detect pattern collapse of the photoresist 32.

[0080] [Hardware] Note that the control in the second and third embodiments described above is realized by, for example, a computer 90 as shown in Fig. 17. Fig. 17 is a diagram showing an example of the hardware configuration of the computer 90. The computer 90 includes a CPU (Central Processing Unit) 91, a RAM (Random Access Memory) 92, a ROM (Read Only Memory) 93, and an auxiliary storage device 94. The computer 90 also includes a communication interface (I / F) 95, an input / output interface (I / F) 96, and a media interface (I / F) 97.

[0081] The CPU 91 operates and controls each part based on a program stored in the ROM 93 or the auxiliary storage device 94. The ROM 93 stores a boot program executed by the CPU 91 when the computer 90 starts up, programs that depend on the hardware of the computer 90, and the like.

[0082] The auxiliary storage device 94 is, for example, a hard disk drive (HDD) or a solid state drive (SSD), and stores programs executed by the CPU 91, data used by the programs, etc. The CPU 91 reads the programs from the auxiliary storage device 94, loads them into the RAM 92, and executes the loaded programs. The communication I / F 95 receives signals and data from the exposure apparatus 10, the camera module 40, etc. via a communication NW (Network) such as a LAN (Local Area Network), and sends them to the CPU 91. The communication I / F 95 also transmits signals and data generated by the CPU 91 to the exposure apparatus 10, etc. via the communication NW.

[0083] The CPU 91 controls the input device and the output device via the input / output I / F 96. The CPU 91 acquires a signal input from the input device via the input / output I / F 96 and sends it to the CPU 91. The CPU 91 also outputs generated data to the output device via the input / output I / F 96.

[0084] The media I / F 97 reads a program or data stored in a recording medium 98 and stores it in the auxiliary storage device 94. The recording medium 98 is, for example, an optical recording medium such as a DVD (Digital Versatile Disc) or a PD (Phase Change Rewritable Disc), a magneto-optical recording medium such as an MO (Magneto-Optical disk), a tape medium, a magnetic recording medium, or a semiconductor memory.

[0085] The CPU 91 of the computer 90 executes the program loaded onto the RAM 92 to realize each process illustrated in the flowchart of Fig. 5 or 10. The CPU 91 of the computer 90 reads the program loaded onto the RAM 92 from the recording medium 98 and stores it in the auxiliary storage device 94. As another example, the CPU 91 of the computer 90 may obtain a program from another device via the communication network and store it in the auxiliary storage device 94.

[0086] [Others] The technology disclosed in the present application is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist thereof.

[0087] For example, in the second embodiment described above, after the marker pattern provided on the reticle 12 is projected onto the photoresist 21, the temperature of the substrate W is lowered from the second temperature to the third temperature. Then, while the substrate W is at the third temperature, the sensor 15 irradiates the photoresist 21 with light including UV light, and a fluorescent image corresponding to the projected marker pattern is acquired. However, the disclosed technology is not limited to this.

[0088] As another example, if the intensity of the light irradiated onto the photoresist 21 is weaker than the intensity of the light irradiated in step S13 and the light irradiation time is shorter than the irradiation time in step S13, the sensor 15 may acquire a fluorescent image while maintaining the second temperature. The time during which the light source 11 irradiates the photoresist 21 with light including UV light in step S13 is an example of a first time, and the time during which the sensor 15 irradiates the photoresist 21 with light including UV light in step S15 is an example of a second time. In an experiment, when light from a UV lamp (wavelength 365 nm, output 8 W) was irradiated onto the sample containing the compound from a position 20 cm or more away from the sample for an irradiation time of 5 seconds or less, the emission color of the compound could be observed without causing a change in the emission color of the compound. This eliminates the need to change the temperature of the substrate W and reduces the time required to correct misalignment.

[0089] In the second embodiment described above, the light emitted in step S13 and the light used to expose the circuit pattern in step S18 are emitted from the same light source 11, but the disclosed technology is not limited to this. In another embodiment, separate light sources may be used for exposure and alignment.

[0090] Furthermore, in the second and third embodiments described above, compound (1) is mixed into the photoresist, but the disclosed technology is not limited to this, and the compound mixed into the photoresist 21 may be compounds (2) to (5).

[0091] In the second and third embodiments described above, the compound (1) is mixed into the photoresist, but the disclosed technology is not limited to this. The material into which the compound (1) is mixed is not limited to the photoresist, and the compound (1) may be mixed into other materials that are used for processing substrates.

[0092] Furthermore, the compound (1) may be mixed into a member provided in an apparatus for processing the substrate W, or a material mixed with the compound (1) may be placed on the surface of a member provided in an apparatus for processing the substrate W. This makes it possible to confirm, after processing of the substrate W, what temperature the member provided in the apparatus for processing the substrate W has been exposed to.

[0093] It should be noted that the disclosed embodiments are illustrative in all respects and should not be considered limiting. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0094] W substrate 10 exposure device 11 light source 12 reticle 13 projection optical system 14 moving stage 15 sensor 20 underlayer 21 photoresist 22 marker 23 area 25 small area 27 marker placement area 30 underlayer 31 anti-reflection film 32 photoresist 33 opening 34 residue 40 camera module

Claims

1. A complex containing a group 13 element that maintains the emission color corresponding to the maximum temperature during a temperature change process as a fixed color even after the temperature change.

2. The complex according to claim 1, wherein the Group 13 element is boron and the complex has a pyridyl enolate ligand as an organic skeleton.

3. The complex according to claim 2, which is a dimethylboron complex having two methyl groups.

4. The complex of claim 3, which is prepared by reacting a pyridyl enolate ligand with boron trifluoride-diethyl ether complex to give a difluoro complex, which is then reacted with methylmagnesium bromide.

5. The complex according to claim 1, having a structure represented by any one of the following chemical formulas (1) to (5).

6. A surface observation method comprising: a1) a step of preparing a material containing a complex containing a Group 13 element that maintains an emission color corresponding to the maximum temperature during a temperature change process as a fixed color even after the temperature change; and a2) a step of irradiating light onto the material and acquiring a fluorescent image.

7. A method for aligning a substrate, comprising: b1) a step of projecting a pattern on a first plate onto a second plate via a projection optical system using light including ultraviolet light, the second plate including a base layer on which a marker is formed, and a material formed on the base layer and including a complex containing a group 13 element that maintains an emission color corresponding to the highest temperature in a temperature change process as a fixed color even after the temperature change; b2) a step of acquiring a fluorescent image of the pattern projected onto the material; and b3) a step of adjusting the position of the second plate based on the positional relationship between the marker and the fluorescent image.

8. The alignment method according to claim 7, comprising: b4) a step performed before step b1) of setting the temperature of the second flat plate to a first temperature; b5) a step performed after step b4) but before step b1) of irradiating the second flat plate with light including ultraviolet light to obtain a first emission spectrum emitted by the material; and b6) a step performed after step b5) but before step b1) of setting the temperature of the second flat plate to a second temperature higher than the first temperature, wherein step b1) is performed while the temperature of the second flat plate is at the second temperature; and wherein step b2) identifies a region of the fluorescent image based on a second emission spectrum emitted by the fluorescent image, the second emission spectrum being different from the first emission spectrum.

9. The alignment method according to claim 8, wherein in step b1), light containing ultraviolet light of a first intensity is irradiated via the projection optical system for a first period of time, and in step b2), light containing ultraviolet light of a second intensity weaker than the first intensity is irradiated onto the material for a second period of time shorter than the first period of time, thereby obtaining the fluorescent image.

10. The alignment method according to claim 8, wherein in step b2), the temperature of the second plate is set to a third temperature lower than the second temperature.

11. An alignment method according to any one of claims 7 to 10, wherein a plurality of markers are formed on the base layer, and after the position of the second flat plate is adjusted in step b3), steps b1) to b3) are further performed for another marker.

12. The alignment method according to any one of claims 7 to 10, wherein steps b1) to b3) are performed for each of a plurality of predetermined small regions on the second flat plate.

13. The alignment method described in claim 12, wherein a plurality of the markers are formed on the base layer in each of the small regions, and after the position of the second flat plate is adjusted for each of the small regions in step b3), steps b1) to b3) are further performed for another marker in the small region.

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