Method for inspecting and manufacturing a photomask and method for manufacturing a semiconductor device

Abstract

The present disclosure provides methods for inspecting and manufacturing a photomask and methods of manufacturing a semiconductor device. In one aspect, a method for inspecting a photomask including a photomask substrate and a reflective layer on the photomask substrate is provided. The method can include loading the photomask on a stage, cooling the photomask substrate to a temperature below room temperature, irradiating a laser beam to the reflective layer on the photomask substrate, receiving the laser beam reflected from the reflective layer using a photodetector to obtain an image of the reflective layer, and detecting a particle defect on the reflective layer or a void defect in the reflective layer based on the image of the reflective layer.

Description

TECHNICAL FIELD

[0001] Embodiments of the present inventive concepts relate to a method for manufacturing a semiconductor device, and more particularly, to a method for inspecting a reticle, a method for manufacturing a reticle, and a method for manufacturing a semiconductor device using the reticle. BACKGROUND

[0002] With the development of information technology, highly integrated semiconductor devices have been developed. The integration density of a semiconductor device can be greatly affected by the wavelength of a light source of a photolithography process. The light source can be an I-line light source, a G-line light source, an excimer laser light source (e.g., KrF or ArF), or an extreme ultraviolet (EUV) light source having a shorter wavelength than the excimer laser light source. The photon energy of the EUV light source can be much greater than that of the excimer laser light source. The EUV light source can cause particle contamination and damage to an EUV reticle. A contaminated EUV reticle can be replaced with a new reticle or can be cleaned. A damaged EUV reticle can be replaced with a new reticle. SUMMARY

[0003] Embodiments of the present inventive concepts can provide a method for inspecting a reticle (which can improve the signal-to-noise ratio of optical inspection and minimize damage to the reticle), a method for manufacturing a reticle, and a method for manufacturing a semiconductor device using the reticle.

[0004] In an aspect, a method for inspecting a reticle is provided. The reticle can include a reticle substrate and a reflective layer on the reticle substrate. The method can include loading the reticle on a stage, cooling the reticle substrate to a temperature lower than room temperature, irradiating a laser beam to the reflective layer on the reticle substrate, receiving the laser beam reflected from the reflective layer using a photodetector to obtain an image of the reflective layer, and detecting whether a particle defect exists on the reflective layer and / or a void defect exists in the reflective layer based on the image of the reflective layer.

[0005] In an aspect, a method for manufacturing a reticle can include forming a reflective layer on a reticle substrate and inspecting the reflective layer. Inspecting the reflective layer can include cooling the reticle substrate to a temperature lower than room temperature, irradiating a laser beam to the reflective layer, receiving the laser beam reflected from the reflective layer using a photodetector to obtain an image of the reflective layer, and detecting whether a defect exists in the reflective layer based on the image of the reflective layer.

[0006] In an aspect, a method for manufacturing a semiconductor device can include performing an exposure process using a photomask, inspecting the photomask, and storing the photomask. The photomask can include a photomask substrate, a reflective layer on the photomask substrate, and an absorptive pattern on the reflective layer. Inspecting the photomask can include cooling the photomask substrate to a temperature below room temperature, irradiating a laser beam to the reflective layer and the absorptive pattern on the photomask substrate, receiving the laser beam reflected from the reflective layer and the absorptive pattern using a photodetector to obtain an image of the reflective layer and the absorptive pattern, and detecting whether a particle exists on the reflective layer and / or on the absorptive pattern based on the image of the reflective layer and the absorptive pattern. BRIEF DESCRIPTION OF DRAWINGS

[0007] The present inventive concepts will become more apparent from the detailed description in conjunction with the accompanying drawings.

[0008] Figure 1 is a block diagram illustrating an apparatus for manufacturing a semiconductor device according to some embodiments of the present inventive concepts.

[0009] Figure 2 is a schematic diagram illustrating an embodiment of an exposure apparatus of Figure 1 .

[0010] Figure 3 is a schematic diagram illustrating an embodiment of an exposure apparatus of Figure 2 .

[0011] Figure 4 is a block diagram illustrating an embodiment of a photomask inspection apparatus of Figure 1 .

[0012] Figure 5 is a cross-sectional view illustrating an example of a photomask inspection module of Figure 4 according to an embodiment.

[0013] Figure 6 is a graph illustrating a heat capacity of a reflective layer and a growth rate of a second laser beam power density varying with a temperature of a photomask of Figure 2 .

[0014] Figure 7 is a cross-sectional view illustrating an example of a photomask inspection module of Figure 4 according to an embodiment.

[0015] Figure 8 is a cross-sectional view illustrating an embodiment of a photomask cleaning module of Figure 4 .

[0016] Figure 9 is a flowchart illustrating a method for manufacturing a semiconductor device according to some embodiments of the present inventive concepts.

[0017] Figure 10is a flowchart showing a method for manufacturing a photomask according to some embodiments of the inventive concept. Figure 2

[0018] Figures 11 to 13 is a process cross-sectional view of a photomask. Figure 3

[0019] Figure 14 is a flowchart showing a method for inspecting a reflective layer of a photomask according to some embodiments of the inventive concept. Figure 3

[0020] Figure 15 is a flowchart showing a method for inspecting a photoresist according to some embodiments of the inventive concept. Figure 13

[0021] Figure 16 is a flowchart showing a method for inspecting a photomask according to some embodiments of the inventive concept. Figure 3

[0022] Figure 17 is an example of a scattering intensity distribution of an image generated by a photomask inspection apparatus according to some embodiments of the inventive concept. DETAILED DESCRIPTION

[0023] Figure 1 shows an apparatus 100 for manufacturing a semiconductor device according to some embodiments of the inventive concept.

[0024] Referring to Figure 1 , an apparatus 100 for manufacturing a semiconductor device according to some embodiments of the inventive concept (hereinafter referred to as a manufacturing apparatus 100) can be a lithography apparatus. The manufacturing apparatus 100 can be used to form a photoresist pattern on a substrate W. In some embodiments, the manufacturing apparatus 100 can include a spinner apparatus 10, an exposure apparatus 20, a photomask manufacturing apparatus 30, a photomask inspection apparatus 40, and a photomask storage apparatus 50.

[0025] ​​​​​The photoresist coating apparatus 10 may be disposed adjacent to the exposure apparatus 20. A substrate W may be transferred between the photoresist coating apparatus 10 and the exposure apparatus 20. The substrate W may include a semiconductor wafer, such as a silicon wafer. The photoresist coating apparatus 10 and the exposure apparatus 20 may form a photoresist pattern on the substrate W. The photoresist coating apparatus 10 may perform a photoresist coating process, a baking process, and a development process. The exposure apparatus 20 may perform a photoresist exposure process using a photomask R. For example, the exposure apparatus 20 may be an extreme ultraviolet (EUV) exposure apparatus, and the photomask R may be an EUV photomask. In some embodiments, the photoresist coating apparatus 10 may include a chuck for holding the wafer, one or more nozzles for performing the coating process and delivering chemicals during the development process, and a heater (e.g., a heater plate) for performing the baking process.

[0026] The photomask manufacturing apparatus 30 can be used to manufacture a photomask R. Although not shown in the figures, the photomask manufacturing apparatus 30 may include a thin-layer deposition module, a photoresist coating module, a photolithography module, an etching module, and a cleaning module. The thin-layer deposition module can be used to deposit a thin layer on the photomask substrate 2 (see figure 2). Figure 11 Thin layers (e.g., silicon, molybdenum, and / or absorber layers) are deposited on the photoresist. The photoresist coating module can be used with photoresist PR (see...). Figure 13 1) Coating a photomask substrate 2. A photolithography module can be used to pattern the coated photoresist PR. An etching module can be used to etch the thin layer (e.g., an absorption layer) along the patterned photoresist PR.

[0027] A photomask inspection device 40 can be disposed between the exposure device 20 and the photomask storage device 50. The photomask inspection device 40 can be used to inspect the photomask R. For example, the photomask inspection device 40 can detect defects in the photomask R (e.g., Figure 5 Particles 8 and / or Figure 11 (gap 9).

[0028] The photomask storage device 50 can store the photomask R temporarily and / or for a long time. The photomask R can be transferred to the exposure device 20, the photomask manufacturing device 30, the photomask inspection device 40 and / or the photomask storage device 50 while being loaded in the photomask cassette.

[0029] Figure 2 Show Figure 1 One embodiment of the exposure device 20.

[0030] Reference Figure 2 The exposure apparatus 20 may include an EUV scanner or an EUV stepper. For example, the exposure apparatus 20 may include a chamber 210, an EUV light source 220, an optical system 230, a first photomask platform 240, a substrate platform 250, and a fast switching device 260.

[0031] The chamber 210 can provide an internal space into which the substrate W and the reticle R are loaded. The internal space of the chamber 210 can be independent from the outside when a process is performed. For example, the chamber 210 can have a vacuum pressure of, for example, 1 x 10 -4 Torr to 1 x 10 -6 Torr. When a gas (e.g., hydrogen) is injected into the chamber 210, the chamber 210 can have an internal pressure of, for example, 1 x 10 -2 Torr to 1 x 10 -4 Torr. The chamber 210 can include a main chamber 212 and an auxiliary chamber 214. The main chamber 212 can surround the EUV light source 220, the optical system 230, the first reticle stage 240, and the substrate stage 250. The auxiliary chamber 214 can be connected to one side of the main chamber 212. The auxiliary chamber 214 can temporarily store the reticle R.

[0032] The EUV light source 220 can be disposed in one side portion of the main chamber 212. The EUV light source 220 can generate an EUV beam 22. The EUV beam 22 can be a beam generated by plasma. In some embodiments, the EUV light source 220 can include a source drop generator 222, a first laser 224, and a collection mirror 226. The source drop generator 222 can generate a source drop 221. The source drop 221 can include a metal droplet of tin (Sn), titanium (Ti), or lithium (Li) or a droplet of xenon (Xe). The first laser 224 can irradiate a first laser beam 223 to the source drop 221 to generate the EUV beam 22. The first laser beam 223 can be a pump light of the EUV beam 22. The intensity of the EUV beam 22 can be proportional to the intensity or power density of the first laser beam 223. The collection mirror 226 can focus or converge the EUV beam 22 to the optical system 230. For example, the collection mirror 226 can include a concave mirror.

[0033] The optical system 230 can be disposed between the first reticle stage 240 and the substrate stage 250. The optical system 230 can sequentially provide the EUV beam 22 to the reticle R and the substrate W. For example, the optical system 230 can include a field facet mirror 232, a pupil facet mirror 234, a grazing mirror 236, and a projection mirror 238. The field facet mirror 232, the pupil facet mirror 234, and the grazing mirror 236 can be used as an illumination system for providing the EUV beam 22 to the reticle R. The field facet mirror 232 can reflect the EUV beam 22 to the pupil facet mirror 234. The pupil facet mirror 234 can reflect the EUV beam 22 toward the reticle R. The field facet mirror 232 and the pupil facet mirror 234 can collimate the EUV beam 22. The grazing mirror 236 can be disposed between the pupil facet mirror 234 and the reticle R. The grazing mirror 236 can adjust a grazing incidence angle of the EUV beam 22. The projection mirror 238 can be used as a projection objective for providing the EUV beam 22 to the substrate W. The projection mirror 238 can provide the EUV beam 22 to the substrate W.

[0034] The first reticle stage 240 can be disposed in an upper region of the inner space of the main chamber 212. The first reticle stage 240 can have a reticle chuck 242. The reticle chuck 242 can electrostatically hold the reticle R by using an electrostatic voltage. For example, the reticle R can be a reflective mask. The reticle R can reflect a portion of the EUV beam 22 to the projection mirror 238 and can absorb another portion of the EUV beam 22. The projection mirror 38 can reflect the reflected portion of the EUV beam 22 to the substrate W. The reticle R can be contaminated by a material used to generate the EUV beam 22 (e.g., a material of the source drop 221). For example, the reticle R can be contaminated by the particle 8. For example, the particle 8 can be a metal nanoparticle of tin (Sn), titanium (Ti), or lithium (Li), or a nanoparticle of xenon (Xe).

[0035] The substrate stage 250 can be disposed in a lower region of the inner space of the main chamber 212. The substrate stage 250 can have a substrate chuck 252. The substrate chuck 252 can receive the substrate W. The substrate chuck 252 can electrostatically hold the substrate W. The substrate W can be exposed to the EUV beam 22. A photoresist on the substrate W can be partially exposed to the EUV beam 22 along a pattern of the reticle R.

[0036] The fast exchange device 260 can be disposed between the first reticle stage 240 and the auxiliary chamber 214 in the main chamber 212. The fast exchange device 260 can exchange the reticle R on the reticle chuck 242. The fast exchange device 260 can transfer the reticle R between the reticle chuck 242 and the auxiliary chamber 214.

[0037] Figure 3 An embodiment of the reticle R is shown. Figure 2

[0038] Referring to​Figure 3 The photomask R can be a reflective light mask. In some embodiments, the photomask R may include a photomask substrate 2, a reflective layer 4, and an absorption pattern 6.

[0039] The photomask substrate 2 may include quartz. Optionally, the photomask substrate 2 may include metal or glass. However, embodiments of the present invention are not limited thereto. The photomask substrate 2 may have a thickness of about 2 mm to about 5 mm.

[0040] The reflective layer 4 can be repeatedly stacked on the photomask substrate 2 approximately 40 to 50 times, but for ease of illustration, it is not shown here. Figure 3 The intermediate reflective layer 4 is shown as being stacked three times. The reflective layer 4 can reflect the EUV beam 22. The reflective layer 4 can have a thickness of approximately 14 nm. The reflective layer 4 may include a silicon layer 3 and a molybdenum layer 5. The silicon layer 3 and the molybdenum layer 5 can be alternately stacked on the photomask substrate 2.

[0041] Absorption pattern 6 can be disposed on reflective layer 4. Absorption pattern 6 can absorb EUV beam 22. Absorption pattern 6 may include tantalum. Absorption pattern 6 may have a thickness of about 50 nm to about 60 nm.

[0042] Figure 4 Show Figure 1 One embodiment of the photomask inspection device 40.

[0043] Reference Figure 4 The photomask inspection device 40 may include a photomask inspection module 410 and a photomask cleaning module 420. The photomask inspection module 410 may be disposed on one side of the photomask cleaning module 420. The photomask inspection module 410 can inspect the particles 8 (see...) of the photomask R. Figure 5 For example, the photomask inspection module 410 can detect defects in the photomask R (e.g., Figure 5 Particles 8 and / or Figure 11 The gap 9). When particles 8 are present on the photomask R, the photomask cleaning module 420 can clean the photomask R to remove the particles 8. The photomask inspection module 410 (such as Figure 4 and Figure 7 Examples in the text may include, but are not limited to, optical spectrometers.

[0044] Figure 5 Show Figure 4 One embodiment of the photomask inspection module 410.

[0045] Reference Figure 5 The photomask inspection module 410 may include a second photomask platform 412, a second laser 414, a semi-reflective mirror 415, an objective lens 416, an eyepiece 418, and a photodetector 419.

[0046] The second reticle stage 412 can receive a reticle substrate 2. The second reticle stage 412 can have a substrate cooler 411. For example, the substrate cooler 411 can include a Peltier device. The substrate cooler 411 can cool the reticle R.

[0047] The second laser 414 can generate a second laser beam 413. The second laser beam 413 can include ArF ultraviolet light (e.g., having a wavelength of 193 nm). The second laser 414 can provide the second laser beam 413 to the half mirror 415.

[0048] The half mirror 415 can be disposed between the objective lens 416 and the eyepiece 418. The half mirror 415 can reflect the second laser beam 413 to the objective lens 416.

[0049] The objective lens 416 can be disposed between the half mirror 415 and the second reticle stage 412. The objective lens 416 can irradiate the second laser beam 413 to the reflective layer 4 and the absorption pattern 6 of the reticle R. The second laser beam 413 can be focused on the reflective layer 4 and the absorption pattern 6. The focused second laser beam 413 can be reflected from the reflective layer 4 and the absorption pattern 6, and then can be provided to the objective lens 416. The objective lens 416 can provide the reflected second laser beam 413 to the half mirror 415. The half mirror 415 can transmit the second laser beam 413 to the eyepiece 418.

[0050] The eyepiece 418 can be disposed between the half mirror 415 and the photodetector 419. The eyepiece 418 can focus the transmitted second laser beam 413 on the photodetector 419.

[0051] The type of the photodetector 419 is not particularly limited, and can include an image sensor circuit, a photodiode, a CCD device, for detecting defects on a reticle (including an EUV reticle). In an example embodiment, Figure 4 (or Figure 7 ) the reticle inspection module 410 can further include a controller 405 for controlling the operation of the reticle inspection module 410 in Figure 4 (or Figure 7 the air blowing device 417 in ).

[0052] The photodetector 419 can receive the second laser beam 413 based on a portion of the second laser beam 413 that is reflected and / or scattered after being irradiated onto the reticle R, and generate a signal based on receiving the second laser beam 413. Based on the signal from the photodetector 419, the controller 405 can obtain and / or generate an image of the reticle R, and determine whether a defect (e.g., a particle 8) is present on the reticle R, as discussed below. Alternatively, based on the signal from the photodetector 419, the controller 405 can determine whether the reticle R is damaged.

[0053] Controller 405 may include: processing circuitry, such as hardware including logic circuitry; hardware / software combinations, such as a processor executing software; or combinations thereof. For example, the processing circuitry may more specifically include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field-programmable gate array (FPGA), a system-on-a-chip (SoC), a programmable logic unit, a microprocessor, an application-specific integrated circuit (ASIC), etc. Controller 405 can control... Figure 4 The photodetector 419, the second laser 414, and the substrate cooler 411 (or Figure 7 The blower device 417 generates an image of the photomask R (and / or a portion thereof) based on the reflection and / or scattering portion of the second laser beam 413 received by the photodetector 419 when the second laser 414 irradiates the photomask R (and / or a portion thereof) with the second laser beam 413.

[0054] As discussed below, the controller 405 controls the photomask inspection module 410 so that while the second laser 414 irradiates the photomask R with the second laser beam 413... Figure 4 The substrate cooler 411 (or Figure 7 The blower device 417 in the middle cools the photomask R, and the controller 405 can be converted into a dedicated controller 405, which improves the functionality of the photomask inspection module 410. Because when Figure 4 The substrate cooler 411 (or Figure 7 When the blower device 417 in the middle cools the photomask R, it can increase the power density of the second laser beam 413 that irradiates the photomask R without damaging the photomask R. Therefore, the controller 405 can improve the function of the photomask inspection module 410.

[0055] In an example implementation, controller 405 may operate photomask inspection module 410 to determine whether a portion of photomask R (e.g., reflective layer 4) has one or more defects (e.g., based on the scattering intensity distribution of the photomask image Rimage generated using signals from photodetector 419). Figure 5 Particles 8 or Figure 11 The gaps in the middle (9). For example, such as Figure 17As shown, the reticle image Rimage generated by the controller 405 using the photodetector 419 can include different levels of the scattering intensity parameter at the corresponding locations (e.g., locations A, B, C) of the reticle image Rimage. In some implementations, the scattering intensity parameter at the corresponding location can be based on a detection signal generated by the photodetector 419 in response to a reflected and / or scattered portion of the second laser beam 413 received by the photodetector 419 when the second laser beam 413 illuminates the corresponding location of the reticle R. In other implementations, the scattering intensity parameter associated with the corresponding location of the reticle image Rimage can be further based on a relationship (e.g., difference) between a reference detection signal with respect to the corresponding location in a reference reticle image (not shown) and the detection signal generated by the photodetector 419 in response to a reflected and / or scattered portion of the second laser beam 413 received by the photodetector 419 when the second laser beam 413 illuminates the corresponding location of the reticle R.

[0056] In some implementations, using the signal from the photodetector 419, the controller 405 can: determine the presence of a first type of defect (e.g., a void 9 in the Figure 11 In some implementations, using the signal from the photodetector 419, the controller 405 can: determine the presence of a first type of defect (e.g., a void 9 in the Figure 5 In some implementations, using the signal from the photodetector 419, the controller 405 can: determine the presence of a first type of defect (e.g., a void 9 in the

[0057] For example, with reference to Figure 4 and Figure 7 The image of the reticle R can have a resolution that is proportional to the power density of the second laser beam 413. In other words, the detection signal of the photodetector 419 can be proportional to the power density of the second laser beam 413, and the noise can be proportional to the square root of the power density of the second laser beam 413. For example, the signal-to-noise (S / N) ratio of the photodetector 419 can increase proportionally to the ratio of the power density of the second laser beam 413 and the square root of the power density.

[0058] A portion of the second laser beam 413 can be absorbed in the reflective layer 4 and the absorbing pattern 6. When the power density of the second laser beam 413 increases, the reflective layer 4 of the reticle R can be over-heated, causing an intermixing failure of the silicon layer 3 and the molybdenum layer 5. When this intermixing failure occurs, the EUV beam 22 (seeFigure 2 The reflectivity of the photomask substrate 2 and the reflective layer 4 may decrease in the exposure apparatus. According to some embodiments of the present invention, the controller 405 can operate the substrate cooler 411 to cool the photomask substrate 2 and the reflective layer 4, thereby increasing the S / N ratio and reducing and / or minimizing damage to the reflective layer 4 (e.g., mixed failures).

[0059] For example, the mixing temperature of silicon layer 3 and molybdenum layer 5 can be approximately 200 degrees Celsius. If the power density of the second laser beam 413 is 0.5 W / cm²... 2 If the temperature is too high, the silicon layer 3 and molybdenum layer 5, which are at room temperature (or ambient temperature, such as 15 degrees Celsius), may be heated to 200 degrees Celsius or higher, leading to hybrid failure. When the power density of the second laser beam 413 is approximately 0.49 W / cm², 2 At this time, the reflective layer 4 can be heated to approximately 200 degrees Celsius. Relative to the silicon layer 3 and molybdenum layer 5 at room temperature (e.g., 15 degrees Celsius), the maximum power density of the second laser beam 413 can be approximately 0.49 W / cm². 2 .

[0060] When the substrate cooler 411 cools the photomask R, the maximum power density of the second laser beam 413 can be increased. When the silicon layer 3 and the molybdenum layer 5 are cooled to approximately 18.5 degrees Celsius and thus have a temperature of approximately -3.5 degrees Celsius, the maximum power density of the second laser beam 413 can increase by approximately 10%. In this case, the power density of the second laser beam 413 can be approximately 0.539 W / cm². 2 When the silicon layer 3 and the molybdenum layer 5 are cooled to approximately 37 degrees Celsius and thus have a temperature of approximately -22 degrees Celsius, the maximum power density of the second laser beam 413 can increase by approximately 20%. In this case, the power density of the second laser beam 413 can be approximately 0.588 W / cm². 2 .

[0061] On the other hand, the reflective layer 4 may have a heat capacity that decreases as the temperature decreases. When the substrate cooler 411 cools the photomask R, the heat capacity of the reflective layer 4 can decrease. When the heat capacity of the reflective layer 4 decreases, the temperature of the photomask R can rise more rapidly as the power density of the second laser beam 413 increases. Furthermore, when the reflective layer 4 is cooled, the energy required to cool it may increase, which may reduce the cooling rate of the reflective layer 4. When the cooling rate of the reflective layer 4 decreases, the substrate cooler 411 may find it difficult to cool the reflective layer 4, and the power density of the second laser beam 413 may not increase.

[0062] Figure 6 Showing Figure 2 The temperature of the photomask R changes the heat capacity of the reflective layer 4 by 80, and the power density of the second laser beam 413 increases by 90.

[0063] Referring to Figure 6 , the heat capacity 80 of the reflective layer 4 can be proportional to the temperature, and the rate of increase 90 of the power density of the second laser beam 413 can be inversely proportional to the temperature. As the temperature of the reflective layer 4 decreases, the heat capacity 80 of the reflective layer 4 can decrease and the rate of increase 90 of the power density of the second laser beam 413 can increase. When the temperature of the reflective layer 4 decreases below about 145 Kelvin (K) (e.g., -128 degrees Celsius), the heat capacity 80 of the reflective layer 4 can decrease rapidly. For example, the gradient of the heat capacity 80 of the reflective layer 4 can be less than about 0.01 at temperatures of about 145 Kelvin (K) or more, and can be equal to or greater than about 0.01 at temperatures of about 145 Kelvin (K) to about 50 Kelvin (K). The reflective layer 4 can be easily cooled at temperatures of about 145 Kelvin (K) or more, but can not be easily cooled at temperatures of about 145 Kelvin (K) or less. At a temperature of about 145 Kelvin (K), the heat capacity 80 of the reflective layer 4 can be about 2.8 J / cm 3 K, and the rate of increase 90 of the power density of the second laser beam 413 can be about 77%. The power density of the second laser beam 413 can be calculated as the sum of the maximum value at room temperature (288 Kelvin (K) or 15 degrees Celsius) (0.49 W / cm 2 ) and the increased power density at the rate of increase 90 of 77% (0.38 W / cm 2 ). As a result, the power density of the second laser beam 413 can increase to about 0.87 W / cm 2 .

[0064] When the reflective layer 4 is cooled to 145 Kelvin (K) or less, the power density of the second laser beam 413 can increase to about 0.87 W / cm 2 or more. However, the heat capacity 80 of the reflective layer 4 can decrease, which can easily cause a mixed failure of the silicon layer 3 and the molybdenum layer 5 of the reflective layer 4.

[0065] At room temperature (e.g., 288 Kelvin (K) or 15 degrees Celsius), the heat capacity 80 of the reflective layer 4 can be about 4 J / cm 3 K, and the rate of increase 90 of the power density of the second laser beam 413 can be 0%. At this time, the maximum value of the power density of the second laser beam 413 (0.49 W / cm 2 ) can be provided.

[0066] Figure 7 An embodiment of the mask inspection module 410 is shown. Figure 4

[0067] Referring to Figure 7 ​The second reticle stage 412 of the reticle inspection module 410 can include a blower device 417. The back surface of the reticle substrate 2 received on the second reticle stage 412 can be exposed to the blower device 417. The blower device 417 can be a cooler for cooling the reticle substrate 2. Under the control of the controller 405, the blower device 417 can provide cooling air 41 to the back surface of the reticle substrate 2 to cool the reflective layer 4 disposed on the reticle substrate 2. The second laser 414, the half mirror 415, the objective lens 416, the ocular lens 418, and the photodetector 419 can be the same as described with reference to Figure 5

[0068] Figure 8 An embodiment of a reticle cleaning module 420 is shown. Figure 4

[0069] Referring to Figure 8 , the reticle cleaning module 420 can include a wet cleaning module, such as a spin wet cleaning device or an immersion wet cleaning device. Alternatively, the reticle cleaning module 420 can include, but is not limited to, a dry cleaning module. In some embodiments, the reticle cleaning module 420 can include a spin chuck 422, a cleaning solution supply unit 424, and a cleaning solution nozzle 426. The spin chuck 422 can spin the reticle R. The cleaning solution supply unit 424 can provide a cleaning solution 428 to the cleaning solution nozzle 426. The cleaning solution nozzle 426 can be disposed above the spin chuck 422. The cleaning solution nozzle 426 can be connected to the cleaning solution supply unit 424. The cleaning solution nozzle 426 can provide the cleaning solution 428 onto the reticle R to clean the reticle R.

[0070] A method of manufacturing a semiconductor device by using the manufacturing apparatus 100 described above will be described hereinafter.

[0071] Figure 9 A method of manufacturing a semiconductor device according to some embodiments of the inventive concepts is shown.

[0072] Referring to Figure 9 , the method of manufacturing a semiconductor device according to some embodiments of the inventive concepts can include manufacturing a reticle R (S100), performing an exposure process (S200), inspecting the reticle R (S300), determining whether there is a particle 8 (S400), cleaning the reticle R when there is the particle 8 (S500), and storing the reticle R (S600).

[0073] First, a reticle R can be manufactured by a reticle manufacturing apparatus 30 (S100).

[0074] Figure 10 An operation S100 of manufacturing a reticle R according to some embodiments of the inventive concepts is shown. Figure 2 An operation S100 of manufacturing a reticle R according to some embodiments of the inventive concepts is shown.​​

[0075] Referring to Figure 10 , the operation S100 of manufacturing the photomask R can include forming a reflective layer 4 (S110), inspecting the reflective layer 4 (S120), determining whether a defect exists in the reflective layer 4 (S130), etching the reflective layer (S140), forming an absorption layer (S150), forming a photoresist (S160), inspecting the photoresist (S170), determining whether a defect exists in the photoresist (S180), removing the photoresist (S190), patterning the photoresist (S192), and forming an absorption pattern 6 (S194).

[0076] Hereinafter, the operation S100 of manufacturing the photomask R will be described in more detail.

[0077] Figures 11 to 13 is a process sectional view of the photomask R of Figure 3 .

[0078] Referring to Figure 10 and Figure 11 , the thin layer deposition module of the photomask manufacturing apparatus 30 can form the reflective layer 4 (S110) on the photomask substrate 2. The reflective layer 4 can include a silicon layer 3 and a molybdenum layer 5. The silicon layer 3 can be formed by a chemical vapor deposition (CVD) method. The molybdenum layer 5 can be formed by a sputtering method or a CVD method.

[0079] Next, the photomask inspection module 410 of the photomask inspection apparatus 40 can inspect the reflective layer 4 (S120). The reflective layer 4 can be inspected by an optical inspection method. The photomask inspection module 410 can obtain a surface image of the reflective layer 4 to detect a defect. For example, the defect can include a particle 8 (see Figure 5 ). Alternatively, the defect can include, but is not limited to, a void 9 (see Figure 11 ), a bump, or a dent of the reflective layer 4.

[0080] Figure 14 shows the operation S120 of inspecting the reflective layer 4 of Figure 3 according to some embodiments of the inventive concept.

[0081] Referring to Figure 14 , the photomask substrate 2 can be loaded on the second photomask stage 412 (S122). An interface apparatus (not shown) can provide the photomask substrate 2 onto the second photomask stage 412. The photomask substrate 2 can be provided on the substrate cooler 411 of the second photomask stage 412.

[0082] Next, the reticle substrate 2 can be cooled by the substrate cooler 411 (S124). The substrate cooler 411 can cool the reticle substrate 2 to a temperature lower than room temperature. For example, the substrate cooler 411 can cool the reticle substrate 2 to about 145 Kelvin (K). The reflective layer 4 can be cooled to a temperature equal to that of the reticle substrate 2.

[0083] Subsequently, the second laser 414 can irradiate the second laser beam 413 to the reflective layer 4 (S126). For example, in the operation S120 of inspecting the reflective layer 4, the operation S124 of cooling the reticle substrate 2 can be used to increase the power density of the second laser beam 413. The power density of the second laser beam 413 can be about 0.49 W / cm 2 or more. For example, the second laser 414 can provide the second laser beam 413 having a power density of about 0.87 W / cm 2 . The second reticle stage 412 can move the reticle substrate 2 to scan the second laser beam 413 over the reflective layer 4. For example, the second laser beam 413 can include ArF ultraviolet light having a wavelength of about 193 nm. The second laser beam 413 can be scanned at a speed of about 12.3 mm / s.

[0084] The photodetector 419 can receive the second laser beam 413 and provide a signal to the controller 405 to detect defects of the reflective layer 4 (S128). As the power density of the second laser beam 413 is increased, the controller 405 can obtain a surface image of the reflective layer 4 having a good S / N ratio based on the signal from the photodetector 419. In addition, the controller 405 can use the signal from the photodetector 419 to detect defects of the reflective layer 4 by using the surface image. The types of defects of the reflective layer 4 can be various. For example, the defects of the reflective layer 4 can include the particles 8. When the particles 8 are the defects of the reflective layer 4, the reticle cleaning module 420 of the reticle inspection apparatus 40 can clean the reticle R to remove the particles 8. Alternatively, the defects of the reflective layer 4 can include the voids 9 (see Figure 11 ) of the reflective layer 4. Hereinafter, the defects of the reflective layer 4, which are the voids 9, will be described. Figure 11

[0085] Referring again to Figure 10 , the reticle inspection apparatus 40 can determine whether there are defects in the reflective layer 4 (S130). For example, referring to Figure 17 , in an embodiment, the controller 405 can use Figure 5 and Figure 7 ​The photodetector 419 in the light shield 3 obtains a light shield image Limage of the light shield 3. Using the signal from the photodetector 419, the controller 405 can: determine that a first type of defect (e.g., a gap 9 in the light shield 3) is present in a portion of the light shield L (e.g., the light shield 3) in response to the scattering intensity parameter I being greater than or equal to a first threshold Th1 and less than a second threshold Th2 (see position C); determine that no defect is present in response to the scattering intensity parameter I being less than or equal to the first threshold Th1 and less than the second threshold (see position B); and determine that a second type of defect (e.g., a particle 8 in the light shield 3) is present in response to the scattering intensity parameter I being greater than or equal to the second threshold Th2 (see position A). However, the inventive concepts are not limited thereto. Figure 11 Figure 5

[0086] When a defect is present in the reflective layer 4 (and / or in response to a defect being present in the reflective layer 4), the etching module of the mask manufacturing apparatus 30 can etch the reflective layer 4 (S140). Accordingly, the reflective layer 4 can be removed from the mask substrate 2. Thereafter, the operation S110 of forming the reflective layer 4, the operation S120 of inspecting the reflective layer 4, and the operation S130 of determining whether a defect is present in the reflective layer 4 can be repeated.

[0087] Referring to Figure 10 and Figure 12 When no defect is present in the reflective layer 4, the thin layer deposition module of the mask manufacturing apparatus 30 can form an absorption layer 7 on the reflective layer 4 (S150). The absorption layer 7 can include tantalum formed by a sputtering method, or a layer having the tantalum.

[0088] Referring to Figure 10 and Figure 13 The photoresist coating module of the mask manufacturing apparatus 30 can form a photoresist PR on the absorption layer 7 (S160). The photoresist PR can be coated by a spin coating method.

[0089] Next, the mask inspection module 410 of the mask inspection apparatus 40 can inspect the photoresist PR (S170). The photoresist PR can be inspected by an optical inspection method. The operation S170 of inspecting the photoresist PR can be an operation of inspecting the photoresist PR and the absorption layer 7.

[0090] Figure 15 The operation S170 of inspecting the photoresist PR according to some embodiments of the inventive concepts is illustrated. Figure 13 The operation S170 of inspecting the photoresist PR according to some embodiments of the inventive concepts is illustrated.

[0091] Referring to Figure 15 The operation S170 of inspecting the photoresist PR can be similar to the operation S120 of inspecting the reflective layer 4.

[0092] ​​The reticle substrate 2 can be loaded on a second reticle stage 412 of the reticle inspection module 410 (S172). The interface device can provide the reticle substrate 2 on a substrate cooler 411 of the second reticle stage 412.

[0093] Next, the reticle substrate 2 can be cooled by the substrate cooler 411 (S174). For example, the substrate cooler 411 can cool the reticle substrate 2 to about 145 Kelvin (K) below room temperature.

[0094] Subsequently, the second laser 414 can irradiate the second laser beam 413 to the photoresist PR (S176). For example, the operation S174 of cooling the reticle substrate 2 can be used to increase the power density of the second laser beam 413 in the operation S170 of inspecting the photoresist PR. The power density of the second laser beam 413 can be about 0.49 W / cm 2 or more. The second laser 414 can provide the second laser beam 413 with a power density of about 0.87 W / cm 2 . The second laser beam 413 can include ArF ultraviolet light with a wavelength of about 193 nm. The second laser beam 413 can be scanned at a speed of about 12.3 mm / s. The second laser beam 413 can be provided without chemical modification and physical deformation of the photoresist PR. The photoresist PR can be photosensitive with respect to light having a wavelength within the EUV range (e.g., 13.5 nm). For example, the second laser beam 413 can have a wavelength within the ultraviolet range (e.g., 193 nm) to the visible light range (e.g., 700 nm), and can reduce and / or minimize the photosensitivity of the photoresist PR to the second laser beam 413.

[0095] The controller 405 can control the photodetector 419 to receive the second laser beam 413 to detect defects of the photoresist PR (S178). The controller 405 can use the photodetector 419 to acquire an image of the photoresist PR. The defects of the photoresist PR can include the voids 9 and / or the particles 8.

[0096] Referring again to Figure 10 , the reticle inspection device 40 can determine whether defects exist in the photoresist PR (S180).

[0097] For example, referring to Figure 17 , in one embodiment, the controller 405 can use similar operations to determine whether defects exist in the photoresist PR as to determine whether defects exist in the reflective layer 4, except that a reticle image Rimage is made for the photoresist PR. The controller 405 can use Figure 5 and Figure 7the photoresist PR. Using the signal from the photodetector 419, the controller 405 can: determine that a first type of defect (e.g., a particle 8 in the photoresist PR) is present in a portion of the reticle R (e.g., the photoresist PR) in response to the scattering intensity parameter I being greater than or equal to a first threshold Thl and less than a second threshold Th2 (see position A); determine that no defect is present in response to the scattering intensity parameter I being less than or equal to the first threshold Thl and less than the second threshold Th2 (see position B); and determine that a second type of defect (e.g., a void 9 in the photoresist PR) is present in response to the scattering intensity parameter I being greater than or equal to the second threshold Th2 (see position C). However, the inventive concepts are not limited thereto. Figure 11 Figure 5

[0098] When a defect is present in the photoresist PR, the photoresist PR can be removed by an ashing device or a cleaning device (S190). Thereafter, the operation S160 of forming the photoresist PR, the operation S170 of inspecting the photoresist PR, and the operation S180 of determining whether a defect is present in the photoresist PR can be repeated.

[0099] When no defect is present in the photoresist PR, a lithography module of the reticle manufacturing device 30 can pattern the photoresist PR (S192).

[0100] Referring to Figure 3 and Figure 10 , the absorption layer 7 can be etched by the etching module using the patterned photoresist PR as an etching mask to form the absorption pattern 6 (S194). The photoresist PR can be removed. The process for manufacturing the reticle R can be completed, and then the reticle R can be provided into the exposure device 20.

[0101] Referring again to Figure 9 , the exposure device 20 can perform an exposure process on a substrate W by using the reticle R (S200). In some embodiments, the reticle R can include an EUV reticle, and the exposure process can include an EUV exposure process. The reticle R can be replaced when the exposure process is performed for a certain time or a failure of the exposure process occurs.

[0102] Next, the reticle R can be inspected by the reticle inspection device 40 (S300).

[0103] Figure 16 The operation S300 of inspecting the reticle R according to some embodiments of the inventive concepts is illustrated. Figure 3

[0104] Referring to Figure 16 ​​​The operation S300 of inspecting the reticle R can be similar to the operation S120 of inspecting the reflective layer 4 and the operation S170 of inspecting the photoresist PR.

[0105] The reticle substrate 2 of the reticle R can be loaded on the second reticle stage 412 (S310). The reticle substrate 2 can be provided on the substrate cooler 411.

[0106] Next, the substrate cooler 411 can cool the reticle substrate 2 (S320). The substrate cooler 411 can cool the reticle substrate 2 to a temperature lower than room temperature. For example, the substrate cooler 411 can cool the reticle substrate 2 to about 145 Kelvin (K). The reflective layer 4 and the absorption pattern 6 can be cooled to a temperature equal to that of the reticle substrate 2.

[0107] Subsequently, the second laser 414 can irradiate the second laser beam 413 to the reflective layer 4 and the absorption pattern 6 (S330). For example, in the operation S300 of inspecting the reticle R, the operation S320 of cooling the reticle substrate 2 can be used to increase the power density of the second laser beam 413. The power density of the second laser beam 413 can be about 0.49 W / cm 2 or more. For example, the second laser 414 can provide the second laser beam 413 having a power density of about 0.87 W / cm 2 . The second laser beam 413 can include ArF ultraviolet light having a wavelength of about 193 nm. The second laser beam 413 can be scanned at a speed of about 12.3 mm / s.

[0108] The photodetector 419 can receive the second laser beam 413 to detect the particles 8 on the reflective layer 4 and the absorption pattern 6 of the reticle R (S340). The photodetector 419 can obtain a surface image of the reflective layer 4 and the absorption pattern 6 of the reticle R having a good S / N ratio. In addition, the photodetector 419 can detect the particles 8 by using the surface image.

[0109] Referring again to Figure 9 , the reticle inspection apparatus 40 can determine whether the particles 8 exist on the reticle R (S400).

[0110] When the particles 8 exist on the reticle R, the reticle R can be cleaned by the reticle cleaning module 420 (S500). The reticle R can be cleaned by a wet cleaning method. Thereafter, the operation S300 of inspecting the reticle R and the operation S400 of determining whether the particles 8 exist on the reticle R can be repeated.

[0111] When the particles 8 do not exist on the reticle R, the reticle R can be stored in the reticle storage apparatus 50 (S600). Nitrogen (N2) can be provided to the reticle R in the reticle storage apparatus 50. The nitrogen can prevent oxidation of the reticle R.

[0112] In the method for inspecting a photomask according to the embodiments of the inventive concept, the photomask substrate can be cooled to increase the S / N ratio of the optical inspection and to reduce and / or minimize damage to the reflective layer of the photomask.

[0113] Although the inventive concept has been described with reference to example embodiments, it will be apparent to those of ordinary skill in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the inventive concept. Accordingly, it is to be understood that the above embodiments are illustrative and not limiting. Therefore, the scope of the inventive concept is to be interpreted only in accordance with the broadest permissible interpretation of the claims and equivalents thereof, and should not be limited or restricted by the above description.

[0114] This application claims priority to Korean Patent Application No. 10-2019-0093406, filed on July 31, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

Claims

1. A method for inspecting a photomask, the method comprising: loading the photomask on a stage, the photomask comprising a photomask substrate and a reflective layer on the photomask substrate; cooling the photomask substrate to a temperature below room temperature; illuminating a laser beam to the reflective layer on the photomask substrate; receiving the laser beam reflected from the reflective layer using a photodetector to obtain an image of the reflective layer; and detecting, based on the image of the reflective layer, whether a particle defect is present on the reflective layer and / or a void defect is present in the reflective layer, wherein the photomask substrate is cooled to below 145 Kelvin to reduce the heat capacity of the reflective layer and increase the power of the laser beam.

3. The method of claim 1, wherein the laser beam comprises ArF ultraviolet light.

2. The method of claim 1, wherein the laser beam has a power density of 0.87 W / cm 2 .

4. The method of claim 1, wherein the laser beam is scanned at a speed of 12.3 mm / s.

5. The method of claim 1, wherein the photomask comprises an extreme ultraviolet photomask.

6. The method of claim 5, wherein the reflective layer of the extreme ultraviolet photomask comprises a silicon layer and a molybdenum layer on the silicon layer.

7. The method of claim 5, wherein the extreme ultraviolet photomask further comprises an absorption pattern on the reflective layer.

8. The method of claim 1, wherein the stage comprises a cooler for cooling the photomask substrate.

9. The method of claim 8, wherein the cooler comprises a Peltier device or a blower device.

10. A method for manufacturing a photomask, the method comprising: forming a reflective layer on a photomask substrate; and inspecting the reflective layer, wherein inspecting the reflective layer comprises: cooling the photomask substrate to a temperature below room temperature, illuminating a laser beam to the reflective layer, receiving the laser beam reflected from the reflective layer using a photodetector to obtain an image of the reflective layer, and detecting, based on the image of the reflective layer, whether a defect is present in the reflective layer, wherein the photomask substrate is cooled to below 145 Kelvin to reduce the heat capacity of the reflective layer and increase the power of the laser beam.

11. The method of claim 10, further comprising: etching the reflective layer in response to the defect being present in the reflective layer.

12. The method of claim 11, further comprising: forming an absorption layer on the reflective layer; forming a photoresist on the absorption layer; inspecting the photoresist; patterning the photoresist; and etching the absorption layer using the patterned photoresist as an etch mask to form an absorption pattern.

13. The method of claim 12, wherein inspecting the photoresist comprises: cooling the photomask substrate to a temperature below the room temperature; illuminating another laser beam to the photoresist; receiving the other laser beam reflected from the photoresist using the photodetector to obtain an image of the photoresist; and detecting, based on the image of the photoresist, a defect in the photoresist.

14. The method of claim 13, further comprising: ​ ​ ​ ​ removing the photoresist in response to the presence of the defects in the photoresist.

15. A method for fabricating a semiconductor device, the method comprising: performing an exposure process using a photomask, the photomask comprising a photomask substrate, a reflective layer on the photomask substrate, and an absorptive pattern on the reflective layer; inspecting the photomask, wherein inspecting the photomask comprises: cooling the photomask substrate to a temperature below room temperature, illuminating a laser beam to the reflective layer and the absorptive pattern on the photomask substrate, receiving, using a photodetector, the laser beam reflected from the reflective layer and the absorptive pattern to obtain an image of the reflective layer and the absorptive pattern, and detecting, based on the image of the reflective layer and the absorptive pattern, whether a particle is present on the reflective layer and / or on the absorptive pattern; and storing the photomask, wherein the photomask substrate is cooled to below 145 Kelvin to reduce the heat capacity of the reflective layer and increase the power of the laser beam.

16. The method of claim 15, further comprising: cleaning the photomask in response to the presence of the particle on the reflective layer and / or the absorptive pattern.

17. The method of claim 16, wherein cleaning the photomask is performed by a wet cleaning method.

18. The method of claim 15, further comprising: fabricating the photomask, wherein fabricating the photomask comprises forming the reflective layer on the photomask substrate; inspecting the reflective layer, wherein inspecting the reflective layer comprises: illuminating another laser beam to the reflective layer, receiving, using the photodetector, the other laser beam reflected from the reflective layer to obtain another image of the reflective layer, and detecting, based on the other image of the reflective layer, whether a defect is present in the reflective layer; and etching the reflective layer in response to the presence of the defect in the reflective layer.

19. The method of claim 15, wherein the photomask comprises an extreme ultraviolet photomask, and the exposure process comprises an extreme ultraviolet exposure process.

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