Cleaning apparatus, cleaning method, and method for manufacturing euvl mask blanks

Abstract

To provide a technology for reducing unevenness in spin cleaning and reducing the footprint.SOLUTION: A cleaning apparatus includes a holding unit that holds a plurality of substrates horizontally, a rotating unit that rotates the plurality of substrates together with the holding unit, and one or more nozzles that form a liquid film of a cleaning liquid on the upper surfaces of the plurality of substrates held by the holding unit. The upper surface of each of the substrates is a rectangle having a pair of long sides and a pair of short sides. Each of the substrates has a first end face and a second end face along the long sides of the rectangle, and a third end face and a fourth end face along the short sides of the rectangle. The holding unit holds the plurality of substrates horizontally with the first end face of one of the substrates facing the first end face of another of the substrates.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a cleaning apparatus, a cleaning method, and a method for manufacturing a mask blank for EUVL.

Background Art

[0002] In recent years, with the miniaturization of semiconductor devices, extreme ultraviolet (EUV) lithography (EUVL), an exposure technique using extreme ultraviolet light (EUV), has been developed. EUV has a wavelength of about 13.5 nm. In EUVL, a reflective mask is used. The reflective mask has, in this order, a substrate such as a glass substrate, a multilayer reflective film that reflects EUV light, and an absorption film that absorbs EUV light. The absorption film may not only absorb EUV light but also shift the phase of EUV light. That is, the absorption film may be a phase shift film. An opening pattern is formed in the absorption film. In EUVL, the opening pattern of the absorption film is transferred to a target substrate such as a semiconductor substrate. Transferring includes reducing and transferring.

[0003] The cleaning method described in Patent Document 1 spin-cleans a substrate. The step of spin-cleaning the substrate includes a step of supplying a cleaning liquid to the upper surface of the substrate while rotating the substrate, and a step of shaking off the cleaning liquid remaining on the upper surface of the substrate while rotating the substrate after stopping the supply of the cleaning liquid. The substrate is a substrate of a liquid crystal display device or a photomask substrate used in the manufacture of a liquid crystal display device. The substrate is a rectangular substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The upper surface of the substrate is, for example, rectangular. The rectangle may not be a square with four equal side lengths. That is, the rectangle may have a pair of long sides and a pair of short sides. The length of the long side is longer than the length of the short side. In this case, when the substrate is rotated about the center of the upper surface of the substrate, the difference between the maximum value and the minimum value of the distance between the rotation center line of the substrate and the periphery of the substrate is large. Therefore, uneven cleaning during spin cleaning is likely to occur. Also, the footprint (installation area) of the cleaning device per substrate is large.

[0006] One aspect of the present disclosure provides a technique for reducing uneven cleaning during spin cleaning and reducing the footprint of the cleaning device per substrate.

Means for Solving the Problems

[0007] A cleaning device according to one aspect of the present disclosure includes a holding unit that horizontally holds a plurality of substrates, a rotating unit that rotates the plurality of substrates together with the holding unit, and one or more nozzles that form a liquid film of a cleaning liquid on the upper surfaces of the plurality of substrates held by the holding unit. The upper surface of each of the substrates is a rectangle having a pair of long sides and a pair of short sides. Each of the substrates has a first end face and a second end face along the long side of the rectangle, and a third end face and a fourth end face along the short side of the rectangle. The holding unit horizontally holds the plurality of substrates with the first end face of one of the substrates facing the first end face of another of the substrates.

Effects of the Invention

[0008] According to one aspect of the present disclosure, by horizontally holding a plurality of substrates with the first end faces of the plurality of substrates facing each other, it is possible to create a rectangle with a small aspect ratio using the plurality of substrates. Therefore, uneven cleaning during spin cleaning can be reduced. Also, the space for rotating one substrate and the space for rotating another substrate can be partially overlapped, and the footprint of the cleaning device per substrate can be reduced.

Brief Description of the Drawings

[0009]

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and the description thereof may be omitted. In the specification, "~" indicating a numerical range means that the numerical values described before and after it are included as the lower limit value and the upper limit value. The numerical range includes the rounded range.

[0011] With reference to FIGS. 1 to 4, a cleaning apparatus 1 according to an embodiment will be described. The cleaning apparatus 1 cleans the upper surface of the substrate W by rotating the horizontally held substrate W and supplying a cleaning liquid L to the upper surface of the substrate W (for example, the first main surface Wa). For example, particles adhering to the substrate W can be removed.

[0012] The cleaning apparatus 1 includes, for example, a holding unit 10, a rotating unit 20, and a nozzle 30. The holding unit 10 horizontally holds a plurality of substrates W. The rotating unit 20 rotates a plurality of substrates W together with the holding unit 10. The nozzle 30 forms a liquid film F of the cleaning liquid L on the upper surfaces of the plurality of substrates W held by the holding unit 10.

[0013] The holding part 10 arranges the upper surfaces of a plurality of substrates W side by side on the same plane. Each substrate W includes a glass substrate, a silicon wafer, or a compound semiconductor wafer. Each substrate W may include a functional film formed on, for example, a glass substrate. The functional film is, for example, a light reflection film, a light absorption film, a conductive film, or an insulating film.

[0014] The holding part 10 includes, for example, as shown in FIG. 1, a plurality of pins 11 arranged at intervals along the periphery of the substrate W. The plurality of pins 11 hold the periphery of the substrate W. The substrate W is horizontally placed on the plurality of pins 11. The holding part 10 has a rotating disk 12 to which the plurality of pins 11 are fixed. The plurality of pins 11 are erected on the upper surface of the rotating disk 12. Note that the holding part 10 may be a vacuum chuck or an electrostatic chuck.

[0015] The rotating part 20 rotates a plurality of substrates W together with the holding part 10. The rotation center line 10R of the holding part 10 is installed vertically. The rotation center line 10R is installed, for example, at the center of the boundary between two adjacent substrates W. The rotating part 20 includes, for example, a servo motor. The rotational driving force of the servo motor is transmitted to the holding part 10 via a pulley and a belt or gears (not shown).

[0016] The nozzle 30 supplies the cleaning liquid L to the upper surface of the substrate W held by the holding part 10. The substrate W is rotating, and the cleaning liquid L spreads wet over the entire upper surface of the substrate W by centrifugal force to form a liquid film F. The nozzle 30 is provided outside the cleaning head 50 described later, but may also be provided inside the cleaning head 50. The number of nozzles 30 may be one or more, and may be plural.

[0017] The cleaning liquid L is, for example, pure water (e.g., deionized water), a mixture of pure water and X (at least one component selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, and acetic acid), a mixture of pure water and Y (at least one component selected from the group consisting of ammonia, tetramethylammonium hydroxide, triethanolamine, choline, sodium hydroxide, potassium hydroxide, and cesium hydroxide), a mixture of pure water and Z (at least one component selected from the group consisting of hydrogen peroxide, perchlorate ion, and periodate ion), a mixture of pure water, X, and Z, or a mixture of pure water, Y, and Z.

[0018] The cleaning liquid L may dissolve at least one gas selected from the group consisting of H2 gas, CO2 gas, N2 gas, O2 gas, O3 gas, and Ar gas. By controlling the dissolved amount of the gas, the generation efficiency of cavitation can be improved, and the removal efficiency of particles can be improved. The gas dissolved in the cleaning liquid L is preferably H2 gas, CO2 gas, or N2 gas, and more preferably CO2 gas.

[0019] As shown in FIG. 2, the substrate W has a first main surface Wa and a second main surface Wb. The holding portion 10 holds the substrate W horizontally with the first main surface Wa or the second main surface Wb facing upward. The first main surface Wa and the second main surface Wb have a rectangular shape. The rectangle may not be a square with equal lengths of the four sides. That is, the rectangle may have a pair of long sides and a pair of short sides. In this specification, the rectangle includes a shape with chamfers at the corners of the rectangle.

[0020] The length of the long side is longer than the length of the short side. The length of the long side is preferably 150% to 250% of the length of the short side, and more preferably 180% to 220% of the length of the short side. When the length of the long side is around 200% of the length of the short side, by arranging two rectangles with the long sides facing each other, a rectangle (including a square) with a small aspect ratio can be newly created.

[0021] The substrate W has a first end face Wc1 and a second end face Wc2 along the long side of the rectangle, and a third end face Wc3 and a fourth end face Wc4 along the short side of the rectangle. The first end face Wc1 and the second end face Wc2 face in opposite directions. Also, the third end face Wc3 and the fourth end face Wc4 face in opposite directions.

[0022] The first end face Wc1, the second end face Wc2, the third end face Wc3, and the fourth end face Wc4 are perpendicular to the first main surface Wa and the second main surface Wb. Although not shown, the substrate W may have a chamfered surface at the boundary between the main surface (the first main surface Wa or the second main surface Wb) and the end face (the first end face Wc1, the second end face Wc2, the third end face Wc3, or the fourth end face Wc4).

[0023] As shown in FIG. 1, the holding portion 10 holds a plurality of substrates horizontally with the first end face Wc1 of one substrate W facing the first end face Wc1 of another substrate W. That is, the holding portion 10 holds a plurality of substrates W horizontally with the first end faces Wc1 of the plurality of substrates W facing each other. A rectangle with a small aspect ratio can be newly created with the plurality of substrates W. The smaller the aspect ratio of the rectangle, the smaller the difference between the maximum value and the minimum value of the distance between the center of the rectangle and the periphery of the rectangle.

[0024] Therefore, the cleaning liquid can be evenly flowed radially from the rotation center line 10R of the holding portion 10, and the cleaning unevenness (including the drying unevenness of spin drying) of spin cleaning can be reduced. Also, the space for rotating one substrate W and the space for rotating another substrate W can be partially overlapped, and the footprint of the cleaning apparatus 1 per substrate W can be reduced.

[0025] According to the present embodiment, when spin cleaning the substrate W, the rotation center line of the substrate W (that is, the rotation center line 10R of the holding portion 10) can be arranged outside the substrate W. Therefore, unlike the case where the rotation center line of the substrate W is arranged at the center of the substrate W as in the prior art, the position where the rotation speed becomes zero on the upper surface of the substrate W can be removed. Thereby, the drying unevenness of spin drying can be reduced.

[0026] The cleaning device 1 preferably includes a guide plate 40. The guide plate 40 guides the cleaning liquid L in a horizontal direction from the upper surface of the substrate W held by the holding portion 10 toward the side opposite to the rotation center line 10R of the holding portion 10. The upper surface of the guide plate 40 and the upper surface of the substrate W are arranged on the same plane. The rotating portion 20 rotates the holding portion 10 and the guide plate 40 about the same rotation center line 10R at the same rotation speed. Thereby, the liquid film F can be continuously formed not only on the upper surface of the substrate W but also on the upper surface of the guide plate 40, and the cleaning unevenness of spin cleaning (including the drying unevenness of spin drying) can be further reduced. The guide plate 40 is preferably arranged on all four sides of the plurality of substrates W held by the holding portion 10.

[0027] The shape of the upper surface of the guide plate 40 is preferably a shape in which a part of a circle is cut off. That is, the periphery of the upper surface of the guide plate 40 preferably has an arc of a certain distance D from the rotation center line 10R of the holding portion 10 and a straight line parallel to the third end surface Wc3 or the fourth end surface Wc4 of the substrate W held by the holding portion 10. The distance D is preferably not less than the maximum value D1 of the distance from the rotation center line 10R of the holding portion 10 to the periphery of the substrate W held by the holding portion 10. The distance D is preferably not more than 120% of the maximum value D1.

[0028] Note that the shape of the upper surface of the guide plate 40 is not limited to a shape in which a part of a circle is cut off, and may be, for example, a rectangle or the like. As long as the liquid film F can be continuously formed not only on the upper surface of the substrate W but also on the upper surface of the guide plate 40, the cleaning unevenness of spin cleaning (including the drying unevenness of spin drying) can be further reduced. However, if the shape of the upper surface of the guide plate 40 is a shape in which a part of a circle is cut off, the footprint of the cleaning device 1 per substrate can be reduced.

[0029] The cleaning device 1 preferably includes a lifting part 42. The lifting part 42 raises and lowers the guide plate 40. The lifting part 42 may raise and lower a plurality of guide plates 40 collectively. Note that the lifting part 42 may be provided for each guide plate 40 and may raise and lower each guide plate 40 independently. The lifting part 42 raises and lowers the guide plate 40 between a cleaning position where the upper surface of the guide plate 40 is on the same plane as the upper surface of the substrate W held by the holding part 10 and a standby position below that position.

[0030] When the nozzle 30 supplies the cleaning liquid L to the upper surface of the substrate W while the rotating part 20 rotates a plurality of substrates W together with the holding part 10, the guide plate 40 is arranged at the cleaning position. On the other hand, when the conveying part 80 described later places the substrate W on the holding part 10 and when removing the substrate W from the holding part 10, the guide plate 40 is arranged at the standby position. While maintaining the detachability of the substrate W, the gap between the substrate W and the guide plate 40 can be narrowed during cleaning of the substrate W.

[0031] During cleaning of the substrate W, the size of the gap between the substrate W and the guide plate 40 is preferably such that the cleaning liquid L can transfer from the upper surface of the substrate W to the upper surface of the guide plate 40. It is possible to suppress the flow of the cleaning liquid L from being disturbed in the gap between the substrate W and the guide plate 40.

[0032] Note that the cleaning device 1 may include a horizontal movement part (not shown) instead of the lifting part 42. The horizontal movement part moves the guide plate 40 in the horizontal direction. The horizontal movement part moves the guide plate 40 between a cleaning position where a narrow gap is formed between the guide plate 40 and the substrate W held by the holding part 10 and a standby position farther away from the rotation center line 10R of the holding part 10 than that position. However, by using the lifting part 42 instead of the horizontal movement part, the footprint of the cleaning device 1 per substrate W can be reduced.

[0033] The cleaning device 1 preferably includes a cleaning head 50, a first moving unit 60, and a second moving unit 70. The cleaning head 50 applies ultrasonic vibration to the liquid film F. The first moving unit 60 moves the cleaning head 50 in a horizontal direction orthogonal to the rotation center line 10R of the holding unit 10. The second moving unit 70 moves the cleaning head 50 in the vertical direction.

[0034] As shown in FIG. 3, the cleaning head 50 includes a vibration surface 51a that contacts the liquid film F and an ultrasonic vibrator 52 that vibrates the vibration surface 51a. The cleaning head 50 includes a diaphragm 51. The diaphragm 51 has a downward vibration surface 51a that contacts the liquid film F and an upward mounting surface 51b to which the ultrasonic vibrator 52 is attached.

[0035] The vibration surface 51a is installed parallel to the upper surface of the substrate W. The size of the vibration surface 51a is smaller than, for example, the size of the upper surface of the substrate W. The shape of the vibration surface 51a is, for example, circular. When the nozzle 30 is provided inside the cleaning head 50, the discharge port of the nozzle 30 is formed in the vibration surface 51a.

[0036] As shown in FIG. 3, the mounting surface 51b may be installed parallel to the vibration surface 51a, or may be installed obliquely with respect to the vibration surface 51a as shown in FIG. 4.

[0037] The ultrasonic vibrator 52 applies ultrasonic vibration to the liquid film F by vibrating the vibration surface 51a, and applies sound pressure to the substrate W. Thereby, the particles attached to the upper surface of the substrate W can be peeled off. The output of the ultrasonic vibrator 52 is controlled by the control unit 90.

[0038] As shown in FIG. 1, the first moving part 60 moves the cleaning head 50 in the horizontal direction orthogonal to the rotation center line 10R of the holding part 10. For example, the first moving part 60 moves the cleaning head 50 in the horizontal direction orthogonal to the rotation center line 10R of the holding part 10 by rotating the turning shaft 61. The turning shaft 61 is arranged vertically. The turning arm 62 rotates about the turning shaft 61 together with the turning shaft 61. The cleaning head 50 is fixed to the tip of the turning arm 62, and the cleaning head 50 rotates about the turning shaft 61 together with the turning shaft 61. Although not shown, the first moving part 60 may move the cleaning head 50 in the horizontal direction orthogonal to the rotation center line 10R of the holding part 10 along a horizontal guide rail.

[0039] The cleaning head 50 moves in the horizontal direction orthogonal to the rotation center line 10R of the holding part 10 while applying ultrasonic vibration to the liquid film F. During the vibration of the ultrasonic vibrator 52, when looking at the cleaning head 50 from above, it is preferable that the cleaning head 50 always overlaps at least one of the substrate W and the guide plate 40. The cleaning head 50 can always be in contact with the liquid film F. When the vibration of the ultrasonic vibrator 52 is performed in a state where the cleaning head 50 is not in contact with the liquid film F, the temperature of the ultrasonic vibrator 52 rises, and the ultrasonic vibrator 52 may malfunction.

[0040] The second moving part 70 adjusts the distance between the cleaning head 50 and the substrate W by moving the cleaning head 50 in the vertical direction. For example, the second moving part 70 moves the cleaning head 50 in the vertical direction by moving the turning shaft 61 in the vertical direction. The second moving part 70 includes, for example, a servo motor. The second moving part 70 may include a ball screw that converts the rotational motion of the servo motor into a linear motion.

[0041] Although not shown, instead of moving the cleaning head 50 in the vertical direction, the second moving part 70 may move the holding part 10 in the vertical direction. In any case, the distance G between the cleaning head 50 and the substrate W can be changed.

[0042] The cleaning device 1 preferably includes a conveying unit 80. The conveying unit 80 conveys the substrate W. In this embodiment, the conveying unit 80 conveys a plurality of substrates W one by one, but it may also convey a plurality of substrates W collectively. The conveying unit 80 places the substrate W on the holding unit 10. Also, the conveying unit 80 removes the substrate W from the holding unit 10. Furthermore, after removing the substrate W from the holding unit 10, the conveying unit 80 can also be turned upside down and placed on the holding unit 10 again.

[0043] As shown in FIG. 5, the conveying unit 80 has, for example, a pair of clamping parts 81, 82. The pair of clamping parts 81, 82 sandwich and support the third end face Wc3 and the fourth end face Wc4 of the substrate W. The conveying unit 80 may have a driving unit (not shown) that approaches or separates the pair of clamping parts 81, 82. The driving unit may move either one of the pair of clamping parts 81, 82 or both of them. The driving unit includes, for example, an air cylinder. The driving unit may also include a motor.

[0044] The pair of clamping parts 81, 82 do not contact the first main surface Wa and the second main surface Wb. Therefore, it is possible to suppress the attachment of dirt to the first main surface Wa and the second main surface Wb. Also, the pair of clamping parts 81, 82 do not contact the first end face Wc1. Therefore, as shown in FIG. 1, a plurality of substrates W can be arranged with the first end faces Wc1 facing each other with a narrow gap.

[0045] When cleaning the substrate W, the size of the gap between the substrates W is preferably such that the cleaning liquid L can transfer from the upper surface of one substrate W to the upper surface of another substrate W. It is possible to suppress the disturbance of the flow of the cleaning liquid L in the gap between the substrates W.

[0046] The conveying unit 80 has a pressing part 83. The pressing part 83 presses the substrate W. The conveying unit 80 has the pressing part 83 facing the second end face Wc2 of the substrate W and does not have it facing the first end face Wc1 of the substrate W. Therefore, it is easy to arrange a plurality of substrates W with the first end faces Wc1 facing each other with a narrow gap. The pressing part 83 suppresses the displacement of the substrate W when the substrate W is turned upside down as described later.

[0047] As shown in FIG. 6, the transfer unit 80 turns the substrate W upside down while arranging the pressing portion 83 to face obliquely downward or downward with respect to the second end surface Wc2 of the substrate W. When the substrate W is turned upside down, the pressing portion 83 can limit the substrate W from slipping and falling due to gravity. The pressing portion 83 only needs to contact the second end surface Wc2 of the substrate W when the substrate W slips and falls due to gravity, and basically does not need to contact the second end surface Wc2.

[0048] Although it will be described in detail later, after the transfer unit 80 turns the substrate W upside down, again, the holding unit 10 holds a plurality of substrates W horizontally with the first end surface Wc1 of one substrate W facing the first end surface Wc1 of another substrate W. Thereby, both the first main surface Wa and the second main surface Wb of the substrate W can be cleaned with the cleaning liquid L.

[0049] Next, with reference to FIGS. 7 to 10, an example of the operation of the transfer unit 80 will be described. First, with reference to FIG. 7, the loading of a plurality of substrates W-1 and W-2 will be described. First, as shown in FIG. 7(A), the elevating unit 42 lowers the guide plate 40 to the standby position, and in that state, the transfer unit 80 places the substrate W-1 on the holding unit 10. The holding unit 10 holds the substrate W-1 horizontally with the first main surface Wa of the substrate W-1 facing upward. Next, as shown in FIG. 7(B), the rotating unit 20 rotates the substrate W-1 together with the holding unit 10 by 180°. Next, as shown in FIG. 7(C), the transfer unit 80 places the substrate W-2 on the holding unit 10. The holding unit 10 holds a plurality of substrates W-1 and W-2 horizontally with the first end surface Wc1 of the substrate W-1 facing the first end surface Wc1 of the substrate W-2. Both of the plurality of substrates W-1 and W-2 are in a state where the first main surface Wa faces upward. Finally, as shown in FIG. 7(D), the elevating unit 42 raises the guide plate 40 to the cleaning position. In that state, while the rotating unit 20 rotates a plurality of substrates W-1 and W-2 together with the holding unit 10, the nozzle 30 supplies the cleaning liquid L to the upper surfaces of the plurality of substrates W-1 and W-2. After that, with the supply of the cleaning liquid L stopped by the nozzle 30, the rotating unit 20 rotates a plurality of substrates W-1 and W-2 together with the holding unit 10 to shake off the cleaning liquid L remaining on the upper surfaces of the plurality of substrates W-1 and W-2.

[0050] Next, with reference to FIGS. 8 and 9, the vertical inversion of a plurality of substrates W-1 and W-2 will be described. First, as shown in FIG. 8(A), the elevating unit 42 lowers the guide plate 40 to the standby position, and in this state, the conveying unit 80 removes the substrate W-1 from the holding unit 10. Next, as shown in FIG. 8(B), the rotating unit 20 rotates the substrate W-2 together with the holding unit 10 by 180°. Next, as shown in FIG. 8(C), the conveying unit 80 vertically inverts the substrate W-1 and then places the substrate W-1 on the holding unit 10. The holding unit 10 holds a plurality of substrates W horizontally with the first end face Wc1 of the substrate W-1 facing the first end face Wc1 of the substrate W-2. At this time, as shown in FIG. 8(D), the substrate W-1 is in a state where the second main surface Wb faces upward, and the substrate W-2 is in a state where the first main surface Wa faces upward. Next, as shown in FIG. 9(A), the conveying unit 80 removes the substrate W-2 from the holding unit 10. Next, as shown in FIG. 9(B), the rotating unit 20 rotates the substrate W-1 together with the holding unit 10 by 180°. Next, as shown in FIG. 9(C), the conveying unit 80 vertically inverts the substrate W-2 and then places the substrate W-2 on the holding unit 10. The holding unit 10 holds a plurality of substrates W-1 and W-2 horizontally with the first end face Wc1 of the substrate W-1 facing the first end face Wc1 of the substrate W-2. At this time, as shown in FIG. 9(D), both of the plurality of substrates W-1 and W-2 are in a state where the second main surface Wb faces upward. Thereafter, although not shown, the elevating unit 42 raises the guide plate 40 to the cleaning position. In this state, while the rotating unit 20 rotates a plurality of substrates W-1 and W-2 together with the holding unit 10, the nozzle 30 supplies the cleaning liquid L to the upper surfaces of the plurality of substrates W-1 and W-2. Thereafter, with the supply of the cleaning liquid L stopped by the nozzle 30, the rotating unit 20 rotates a plurality of substrates W-1 and W-2 together with the holding unit 10 to shake off the cleaning liquid L remaining on the upper surfaces of the plurality of substrates W-1 and W-2.

[0051] Next, with reference to FIG. 10, the unloading of the plurality of substrates W-1 and W-2 will be described. First, as shown in FIG. 10(A), the lifting unit 42 lowers the guide plate 40 to the standby position. Next, as shown in FIG. 10(B), the conveying unit 80 removes the substrate W-1 from the holding unit 10. Next, as shown in FIG. 10(C), the rotating unit 20 rotates the substrate W-2 together with the holding unit 10 by 180°. Finally, as shown in FIG. 10(D), the conveying unit 80 removes the substrate W-2 from the holding unit 10.

[0052] As shown in FIG. 1, the cleaning device 1 preferably includes a control unit 90. The control unit 90 is, for example, a computer and includes an arithmetic unit 91 such as a CPU (Central Processing Unit) and a storage unit 92 such as a memory. The storage unit 92 stores programs for controlling various processes executed in the cleaning device 1. The control unit 90 controls the operation of the cleaning device 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92.

[0053] Next, with reference to FIG. 11, a method for manufacturing the EUVL mask blank 100 shown in FIG. 13 will be described. The method for manufacturing the EUVL mask blank 100 has steps S101 to S107. For example, a glass substrate 110 shown in FIG. 12 is prepared in advance.

[0054] The glass of the glass substrate 110 is preferably quartz glass containing TiO2. Quartz glass has a smaller linear expansion coefficient and smaller dimensional changes due to temperature changes compared to general soda-lime glass. The quartz glass may contain 80% to 95% by mass of SiO2 and 4% to 17% by mass of TiO2. When the TiO2 content is 4% to 17% by mass, the linear expansion coefficient near room temperature is substantially zero, and almost no dimensional change occurs near room temperature. The quartz glass may contain a third component or impurity other than SiO2 and TiO2.

[0055] The first main surface 110a and the second main surface 110b of the glass substrate 110 are, for example, rectangles with a length of 304 mm and a width of 152 mm. Note that the vertical and horizontal dimensions are not particularly limited.

[0056] Step S101 includes polishing the first main surface 110a and the second main surface 110b of the glass substrate 110. In this embodiment, the first main surface 110a and the second main surface 110b are polished simultaneously by a double-sided polishing machine (not shown), but they may also be polished sequentially by a single-sided polishing machine (not shown). In step S101, the glass substrate 110 is polished while supplying a polishing slurry between the polishing pad and the glass substrate 110.

[0057] As the polishing pad, for example, a urethane-based polishing pad, a non-woven fabric-based polishing pad, or a suede-based polishing pad is used. The polishing slurry includes an abrasive and a dispersion medium. The abrasive is, for example, cerium oxide particles. The dispersion medium is, for example, water or an organic solvent. The first main surface 110a and the second main surface 110b may be polished multiple times with abrasives of different materials or particle sizes.

[0058] Note that the abrasive used in step S101 is not limited to cerium oxide particles, and may be, for example, silicon oxide particles, aluminum oxide particles, zirconium oxide particles, titanium oxide particles, diamond particles, or silicon carbide particles.

[0059] Step S102 includes measuring the surface shape of the first main surface 110a and the second main surface 110b of the glass substrate 110. For measuring the surface shape, for example, a non-contact measuring machine such as a laser interferometer is used so that the surface is not damaged.

[0060] Step S103 includes locally processing the first main surface 110a and the second main surface 110b of the glass substrate 110 to improve flatness with reference to the measurement results of step S102. The first main surface 110a and the second main surface 110b are locally processed in sequence. The sequence may be either first, and is not particularly limited.

[0061] For local processing, at least one selected from, for example, the GCIB (Gas Cluster Ion Beam) method, the PCVM (Plasma Chemical Vaporization Machining) method, the polishing method using magnetic fluid, and the polishing using a rotary polishing tool is used.

[0062] Step S104 includes performing finish polishing on the first main surface 110a and the second main surface 110b of the glass substrate 110. In the present embodiment, the first main surface 110a and the second main surface 110b are polished simultaneously by a double-sided polishing machine (not shown), but may be polished sequentially by a single-sided polishing machine (not shown). In step S104, the glass substrate 110 is polished while supplying a polishing slurry between the polishing pad and the glass substrate 110. The polishing slurry contains an abrasive. The abrasive is, for example, colloidal silica particles.

[0063] Step S105 includes forming the conductive film 140 shown in FIG. 13 on the second main surface 110b of the glass substrate 110. The conductive film 140 is used to adsorb the EUVL mask to the electrostatic chuck of the exposure apparatus. The conductive film 140 is formed of, for example, chromium nitride (CrN). As a method for forming the conductive film 140, for example, a sputtering method is used.

[0064] Step S106 includes forming the multilayer reflective film 120 shown in FIG. 13 on the first main surface 110a of the glass substrate 110. The multilayer reflective film 120 reflects EUV. The multilayer reflective film 120 is, for example, a laminate of a high refractive index layer and a low refractive index layer alternately stacked. The high refractive index layer is formed of, for example, silicon (Si), and the low refractive index layer is formed of, for example, molybdenum (Mo). As a method for forming the multilayer reflective film 120, for example, a sputtering method such as an ion beam sputtering method or a magnetron sputtering method is used.

[0065] Step S107 includes forming an absorption film 130 shown in FIG. 13 on the multilayer reflective film 120 formed in step S106. The absorption film 130 absorbs EUV. The absorption film 130 may be a phase shift film and may shift the phase of EUV. The absorption film 130 is formed of, for example, a single metal, alloy, nitride, oxide, oxynitride, etc. containing at least one element selected from tantalum (Ta), chromium (Cr), ruthenium (Ru), iridium (Ir), palladium (Pd). As a method for forming the absorption film 130, for example, a sputtering method is used.

[0066] Note that steps S106 to S107 are performed after step S105 in this embodiment, but may be performed before step S105.

[0067] By the above steps S101 to S107, the EUVL mask blank 100 shown in FIG. 13 is obtained. The EUVL mask blank 100 has a conductive film 140, a glass substrate 110, a multilayer reflective film 120, and an absorption film 130 in this order. Note that the EUVL mask blank 100 may include another film in addition to the conductive film 140, the glass substrate 110, the multilayer reflective film 120, and the absorption film 130.

[0068] For example, the EUVL mask blank 100 may further include a low reflection film. The low reflection film is formed on the absorption film 130. Thereafter, an opening pattern 131 is formed on both the low reflection film and the absorption film 130. The low reflection film is used for inspecting the opening pattern 131 and has lower reflection characteristics than the absorption film 130 with respect to inspection light. The low reflection film is formed of, for example, TaON or TaO. As a method for forming the low reflection film, for example, a sputtering method is used.

[0069] Furthermore, the EUVL mask blank 100 may further include a protective film. The protective film is formed between the multilayer reflective film 120 and the absorption film 130. The protective film protects the multilayer reflective film 120 so that the multilayer reflective film 120 is not etched when etching the absorption film 130 to form the opening pattern 131 in the absorption film 130. The protective film is formed of, for example, Ru, Si, Rh, or TiO2. As a method for forming the protective film, for example, a sputtering method is used.

[0070] As shown in FIG. 14, the EUVL mask 101 is obtained by forming an opening pattern 131 in the absorption film 130 of the EUVL mask blank 100. For forming the opening pattern 131, a photolithography method and an etching method are used. Therefore, the resist film used for forming the opening pattern 131 may be included in the EUVL mask blank 100.

[0071] By the way, during the manufacturing process of the EUVL mask blank 100, the glass substrate 110 or various functional films formed on the glass substrate 110 may be cleaned. Cleaning using a chemical reaction with an acid or an alkali, cleaning using a physical action, or cleaning using a combination thereof is performed. The cleaning using a physical action is ultrasonic cleaning, scrub cleaning, or two-fluid cleaning. In two-fluid cleaning, the cleaning liquid L and a gas are mixed and sprayed.

[0072] The cleaning of the glass substrate 110 or the cleaning of various functional films formed on the glass substrate 110 is performed, for example, using the cleaning apparatus 1 shown in FIG. 1. The cleaning using the cleaning apparatus 1 is preferably performed at least one of between step S104 and S105, between step S105 and S106, between step S106 and S107, and after step S107. Also, the cleaning using the cleaning apparatus 1 may be performed on the low-reflection film, the hard mask film, or the protective film.

[0073] As described above, the cleaning apparatus, the cleaning method, and the method for manufacturing a mask blank for EUVL according to the present disclosure have been described. However, the present disclosure is not limited to the above embodiments and the like. Within the scope described in the claims, various changes, modifications, substitutions, additions, deletions, and combinations are possible. Naturally, these also belong to the technical scope of the present disclosure.

Description of Reference Numerals

[0074] 1 Cleaning apparatus 10 Holding unit 20 Rotating unit 30 Nozzle F Liquid film L Cleaning liquid W Substrate Wc1 First end face Wc2 Second end face Wc3 Third end face Wc4 Fourth end face

Claims

1. A holding part that horizontally holds a plurality of substrates; A rotating part that rotates a plurality of the substrates together with the holding part; One or more nozzles that form a liquid film of a cleaning liquid on the upper surfaces of the plurality of substrates held by the holding part; Comprising; The upper surface of each of the substrates is a rectangle having a pair of long sides and a pair of short sides, Each of the substrates has a first end face and a second end face along the long side of the rectangle, and a third end face and a fourth end face along the short side of the rectangle, The holding part is a cleaning device that horizontally holds a plurality of the substrates with the first end face of one of the substrates facing the first end face of another of the substrates.

2. Comprising a transport part that transports the substrate, The transport part has a pair of clamping parts that support the substrate with the third end face and the fourth end face of the substrate therebetween. The cleaning device according to Claim 1.

3. The transport part has a pressing part that presses the substrate, facing the second end face and not facing the first end face. The cleaning device according to Claim 2.

4. The transport part turns the substrate upside down while arranging the pressing part obliquely below or below the second end face of the substrate, After the transport part turns the substrate upside down, again, the holding part horizontally holds a plurality of the substrates with the first end face of one of the substrates facing the first end face of another of the substrates. The cleaning device according to Claim 3.

5. Comprising a guide plate that guides the cleaning liquid horizontally from the upper surface of the substrate held by the holding part toward the side opposite to the rotation center line of the holding part, The rotating part rotates the holding part and the guide plate about the same rotation center line at the same rotation speed. The cleaning device according to Claim 1.

6. Comprising a lifting part that raises and lowers the guide plate. The cleaning device according to Claim 5.

7. A cleaning head including a vibration surface that contacts the liquid film and an ultrasonic vibrator that vibrates the vibration surface, A moving part that moves the cleaning head in a horizontal direction perpendicular to the rotation center line of the holding part, Comprising. The cleaning device according to Claim 5.

8. A cleaning method including cleaning the substrate using the cleaning device according to any one of Claims 1 to 7.

9. A method for manufacturing an EUVL mask blank including cleaning a glass substrate or a functional film formed on the glass substrate using the cleaning device according to any one of Claims 1 to 7.

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