Method for processing a target supply device, method for manufacturing an electronic device, and inspection method.

Abstract

When baking is performed with the target material already in the tank, there was a problem in that even if the temperature was set above the melting point, the effect of removing residual moisture could not be improved. [Solution] A method for processing a target supply device that supplies a target into a chamber for generating EUV light, the target supply device comprising a tank capable of accommodating a target, a filter housed in the tank, and a nozzle communicating with the tank and capable of discharging a molten target, the method comprising: a first step of heating the tank to a temperature above the melting point of the target before placing the target in the tank; and a second step of placing the target in the tank after the first step.

Description

[Technical Field]

[0001] This disclosure relates to a processing method for a target supply device, a method for manufacturing an electronic device, and a method for inspection. [Background technology]

[0002] In recent years, with the miniaturization of semiconductor processes, the miniaturization of transfer patterns in semiconductor photolithography has been progressing rapidly. Next-generation models will require microfabrication of 10 nm or less. Therefore, the development of semiconductor exposure equipment combining a device for generating extreme ultraviolet (EUV) light with a wavelength of approximately 13 nm with a reduction projection reflective optical system is highly anticipated.

[0003] As for EUV light generation devices, development is progressing on Laser Produced Plasma (LPP) type devices that use plasma generated by irradiating a target material with laser light. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6513106 [Patent Document 2] Summary of Japanese Patent Publication No. 2023-011243

[0005] A method for processing a target supply device according to one aspect of the present disclosure is a method for processing a target supply device that supplies a target into a chamber for generating EUV light, the target supply device comprising a tank capable of accommodating a target, a filter housed in the tank, and a nozzle communicating with the tank and capable of discharging a molten target, the method comprising a first step of heating the tank to a temperature above the melting point of the target before placing the target in the tank, and a second step of placing the target in the tank after the first step.

[0006] A method for manufacturing an electronic device according to one aspect of the present disclosure includes outputting EUV light generated by an EUV light generating apparatus to an exposure apparatus in order to manufacture an electronic device, thereby exposing a photosensitive substrate to EUV light in the exposure apparatus. The EUV light generating apparatus comprises an EUV light generating apparatus comprising: a chamber that generates EUV light by irradiating a supplied target with laser light; a target supplying apparatus for supplying a target into the chamber, the target supplying apparatus comprising: a tank capable of accommodating a target; a filter housed in the tank; and a nozzle communicating with the tank and capable of discharging a molten target, and the target supplying apparatus being subjected to a process including: a first step of heating the tank to a temperature exceeding the melting point of the target before placing the target in the tank; and a second step of placing the target in the tank after the first step.

[0007] A method for manufacturing an electronic device according to one aspect of the present disclosure includes: a chamber that generates EUV light by irradiating a supplied target with laser light; a target supply device that supplies a target into the chamber, the target supply device comprising a tank capable of accommodating a target, a filter housed in the tank, and a nozzle communicating with the tank and capable of discharging a molten target, wherein the target supply device is subjected to a process that includes a first step of heating the tank to a temperature exceeding the melting point of the target before placing the target into the tank, and a second step of placing the target into the tank after the first step; irradiating a mask with EUV light generated by such an EUV light generator to inspect the mask for defects; selecting a mask using the inspection results; and exposing and transferring a pattern formed on the selected mask onto a photosensitive substrate. [Brief explanation of the drawing]

[0008] Some embodiments of this disclosure are described below, merely as examples, with reference to the accompanying drawings. [Figure 1] Figure 1 is a schematic diagram showing the configuration of an LPP-type EUV light generator. [Figure 2] Figure 2 is a cross-sectional view showing the configuration of a target supply device according to a comparative example. [Figure 3] Figure 3 is a main flowchart showing the operation of the target supply device according to the comparative example. [Figure 4] Figure 4 is a flowchart showing the baking processing procedure of the target supply device according to the comparative example. [Figure 5] Figure 5 is a timing chart according to the comparative example. [Figure 6] Figure 6 is a diagram schematically showing the state of the tank before heating according to the comparative example. [Figure 7] Figure 7 is a diagram schematically showing the state of the tank after heating according to the comparative example. [Figure 8] Figure 8 is a flowchart showing the operation of the target supply device according to the first embodiment. [Figure 9] Figure 9 is an example of a timing chart according to the first embodiment. [Figure 10] Figure 10 is a diagram schematically showing the state of the tank after heating according to the first embodiment. [Figure 11] Figure 11 is a flowchart showing an example of the baking processing procedure of the target supply device according to the second embodiment. [Figure 12] Figure 12 is an example of a timing chart according to the second embodiment. [Figure 13] Figure 13 is a diagram showing an example of the use of the baking dedicated chamber. [Figure 14] Figure 14 is a diagram schematically showing the configuration of the exposure apparatus. [Figure 15] Figure 15 is a diagram schematically showing the configuration of the inspection apparatus. Embodiment

[0009] <Content> 1. Overall description of EUV light generation system 1.1 Configuration 1.2 Operation 2. Target supply device according to the comparative example 2.1 Configuration 2.2 Operation 2.3 Problems 3. Target supply device of the first embodiment 3.1 Configuration 3.2 Operation 3.3 Effects 4. Target supply device of the second embodiment 4.1 Configuration 4.2 Operation 4.3 Effects 5. Variations 6. Others

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. The embodiments described below are examples of the disclosure and are not intended to limit the scope of this disclosure. Furthermore, not all configurations and operations described in each embodiment are necessarily essential to the configurations and operations of this disclosure. The same reference numerals are used for identical components, and redundant descriptions are omitted.

[0011] 1. Overall description of the EUV light generation system 1.1 Configuration Figure 1 schematically shows the configuration of an LPP-type EUV light generation system 11. The EUV light generation device 1 is used together with at least one laser device 3. In this application, the system including the EUV light generation device 1 and the laser device 3 is referred to as the EUV light generation system 11. As shown in Figure 1 and described in detail below, the EUV light generation device 1 includes a chamber 2 and a target supply device 26. The chamber 2 is configured to be sealable. The target supply device 26 includes a target material supply device 40 and a target generation device 50. The target material supply device 40 supplies the target material 27 to the target generation device 50. The target generation device 50 generates the target 27 from the target material 27 and discharges the target 27 into the chamber 2. The target generation device 50 is mounted, for example, so that part of it penetrates the wall of the chamber 2. The target material 27 contains tin. The material for target 27 may also include a combination of tin with terbium, gadolinium, lithium, or xenon.

[0012] The wall of chamber 2 is provided with at least one through-hole. A window 21 is provided in the through-hole. Pulsed laser light 32 output from the laser device 3 passes through the window 21. Inside chamber 2, for example, a laser light focusing optical system 22 and an EUV focusing mirror 23 are arranged. The laser light focusing optical system 22 focuses the pulsed laser light 32 into the plasma generation region 25. The EUV focusing mirror 23 has a spheroidal reflective surface and has first and second focal points. A multilayer reflective film is formed on the surface of the EUV focusing mirror 23, for example, in which molybdenum and silicon are alternately layered. The EUV focusing mirror 23 is arranged such that, for example, its first focal point is located in the plasma generation region 25 and its second focal point is located in the intermediate focal point (IF) 292. A through-hole 24 is provided in the center of the EUV focusing mirror 23. Pulsed laser light 32 passes through the through-hole 24. The pulsed laser light 32 is an example of the "laser light" relating to the technology of this disclosure.

[0013] Furthermore, the EUV light generator 1 includes a connecting section 29 that connects the inside of the chamber 2 to the inside of the external device 6. Inside the connecting section 29, there is a wall 291 in which an aperture 293 is formed. The wall 291 is positioned such that the aperture 293 is located at the second focal position of the EUV focusing mirror 23. The external device 6 is an exposure or inspection device that uses the EUV light generated by the EUV light generator 1.

[0014] Furthermore, the EUV light generation device 1 includes an EUV light generation processor 5, a laser beam propagation direction control unit 34, a laser beam focusing optical system 22, a target recovery unit 28, a gas supply device 31, and a gas exhaust device 30. The laser beam propagation direction control unit 34 includes, for example, optical elements 34A and 34B for defining the propagation direction of the pulsed laser beam 32, and actuators for adjusting the position, orientation, etc., of these optical elements 34A and 34B. The target recovery unit 28 recovers the target 27 discharged by the target generation device 50. The gas supply device 31 supplies inert gas into the chamber 2. The gas exhaust device 30 exhausts the inert gas from the chamber 2.

[0015] 1.2 Operation As shown in Figure 1, the pulsed laser light 32 output from the laser device 3 passes through the laser beam direction control unit 34, through the window 21, and enters the chamber 2. The pulsed laser light 32 travels through the chamber 2 along at least one optical path, is reflected by the EUV focusing mirror 23, and irradiates the target 27.

[0016] The target generation device 50 melts the material of the target 27 and ejects the molten target 27 as a droplet toward the plasma generation region 25 inside the chamber 2. The target 27 is irradiated with at least one pulse contained in the pulsed laser light 32. The target 27 irradiated with the pulsed laser light 32 becomes plasma, and synchrotron radiation 251 is emitted from the plasma. The EUV focusing mirror 23 reflects the EUV light 252 contained in the synchrotron radiation 251 with a higher reflectivity than light in other wavelength ranges. The EUV light 252 reflected by the EUV focusing mirror 23 is focused at the intermediate focusing point 292 and output to the external device 6. Note that multiple pulses contained in the pulsed laser light 32 may be irradiated onto a single target 27.

[0017] The EUV photogeneration processor 5 oversees the control of the entire EUV photogeneration system 11. For example, the EUV photogeneration processor 5 controls the timing at which the target 27 is output via the target supply device 26. Furthermore, the EUV photogeneration processor 5 controls, for example, the oscillation timing of the laser device 3, the direction of propagation of the pulsed laser beam 32, and the focusing position of the pulsed laser beam 32. The EUV photogeneration processor 5 also states that the various controls described above are merely examples, and other controls may be added as needed.

[0018] 2. Target supply device according to comparative example 2.1 Configuration Figure 2 shows the configuration of a target supply device 26 according to a comparative example. In the target supply device 26, the target generation device 50 includes a target generation processor 51, a droplet supply unit 52, an inert gas supply unit 53, an exhaust device 54, and a temperature control processor 55.

[0019] The target generation processor 51 controls the target generation device 50. The droplet supply unit 52 includes a melting tank 61, a heater 62, a nozzle 63, a piezoelectric element 64, a filter 65, and a temperature control processor 55. The melting tank 61 is a tank that melts the target material 27 (hereinafter referred to as target material 27A) and contains the molten target 27. The melting tank 61 has a large tank 61A and a small tank 61B which has a smaller capacity than the large tank 61A. The target material supply device 40 is connected to the large tank 61A, and the small tank 61B is located downstream of the large tank 61A. A nozzle 63 is located downstream of the small tank 61B. The melting tank 61 is provided with heaters 62 in both the large tank 61A and the small tank 61B. The heaters 62 are jacket-type heaters, for example, that are attached by wrapping them around the outer circumference of the melting tank 61. The molten tank 61 is heated by the heater 62, and the target material 27A inside the molten tank 61 is melted. The molten tank 61 is an example of a "tank" related to the technology of this disclosure. The molten tank 61 will be referred to simply as tank 61 below.

[0020] The filter 65 is housed in the tank 61. For example, the filter 65 is positioned near the boundary between the large tank 61A and the small tank 61B. The molten target 27 flows from the large tank 61A through the filter 65 into the small tank 61B and the nozzle 63. A heater 62 is also provided around the nozzle 63. The filter 65 removes impurities contained in the target 27. The filter 65 is made of a porous material and, as will be described later, for example, has a configuration in which multiple filter layers with different pore sizes are stacked (see Figure 6). The impurities are particles, including tin oxide, contained in the molten target 27.

[0021] A piezoelectric element 64 is positioned near the nozzle hole in the nozzle 63. A piezoelectric power supply 66 is connected to the piezoelectric element 64 to supply driving power to the piezoelectric element 64. The target generation processor 51 inputs a drive signal of a preset driving frequency to the piezoelectric element 64 via the piezoelectric power supply 66. The piezoelectric element 64 vibrates the nozzle 63 in response to the input drive signal. The target 27 that flows into the nozzle hole becomes columnar due to the pressure difference between the pressure in the tank 61 and the pressure in the chamber 2. When the nozzle 63 vibrates in this state, the columnar target 27 is broken into droplets, and the target 27 is discharged into the chamber 2 as droplets.

[0022] A heater power supply 67 is connected to the heater 62 to supply power for driving the heater 62. The heater 62 is also equipped with a temperature sensor 68, which inputs the measured temperature to the temperature control processor 55.

[0023] The temperature control processor 55 controls the temperature of the tank 61 and nozzle 63 via the heater power supply 67 and temperature sensor 68. Based on the temperature measured by the temperature sensor 68, the temperature control processor 55 controls the operation of the heater 62 via the heater power supply 67. This controls the temperature of the tank 61 and nozzle 63. The temperature control processor 55 can also individually control the heaters 62 provided in, for example, the large tank 61A, the small tank 61B, and the nozzle 63.

[0024] The primary function of heater 62 is to melt the target 27 for EUV light generation, but heater 62 is also used for baking the filter 65. In the tank 61, moisture may adhere to and remain not only inside the filter 65 but also on the inner walls of the tank 61. This residual moisture reacts with the tin contained in the molten target 27 to produce tin oxide. Tin oxide may clog the nozzle holes of nozzle 63, and if the nozzle holes are clogged, the discharge rate of the target 27 discharged as droplets by nozzle 63 may decrease. Baking is a process of heating the temperature inside the tank 61, including the filter 65, in order to gasify the residual moisture and discharge it outside the tank 61. Baking is an example of a "process applied to a target supply device" according to the technology of this disclosure.

[0025] The inert gas supply unit 53 supplies inert gas into the tank 61. The inert gas supply unit 53 is, for example, a gas cylinder, and contains high-pressure noble gases such as argon and helium as pressurized gases. The inert gas supply unit 53 is connected to the large tank 61A via a supply pipe 71. A pressure regulator 72 is located on the supply pipe 71. The pressure regulator 72 adjusts the gas pressure supplied from the inert gas supply unit 53.

[0026] The exhaust device 54 exhausts the gas from the tank 61. An opening 77 is provided in the wall of the large tank 61A, and an exhaust pipe 73 is attached to the opening 77. The exhaust device 54 is connected to the large tank 61A via the exhaust pipe 73. The target generation processor 51 controls the pressure inside the tank 61 by controlling the pressure regulator 72 and the exhaust device 54. The target generation processor 51 also discharges residual moisture that has been gasified by baking to the outside of the tank 61 through the exhaust device 54.

[0027] The target material supply device 40 includes a supply tank 41, a material discharge mechanism 42, a load lock chamber 43, a material supply pipe 44, a liquid level sensor 45, and a supply control processor 46. The supply control processor 46 controls each part of the target material supply device 40.

[0028] The replenishment tank 41 contains the target material 27A. The target material 27A is a solid, and for example, it is spherical. The material discharge mechanism 42 has a measuring instrument for measuring the amount of target material 27A to be replenished. Based on instructions from the replenishment control processor 46, the material discharge mechanism 42 discharges the measured amount of target material 27A from the replenishment tank 41 into the load lock chamber 43.

[0029] The load lock chamber 43 is located downstream of the material discharge mechanism 42 and is connected to the large tank 61A via the material supply pipe 44. The load lock chamber 43 temporarily holds one replenishment amount of target material 27A discharged from the material discharge mechanism 42. Based on instructions from the replenishment control processor 46, the load lock chamber 43 replenishes the stored target material 27A to the large tank 61A. The pressure in the load lock chamber 43 is regulated by the control of a pressure regulator 72 and an exhaust device 54 via the material supply pipe 44, an exhaust pipe 73, and a valve (not shown).

[0030] The liquid level sensor 45 detects the liquid level of the molten target 27 in the large tank 61A. The liquid level sensor 45 is, for example, rod-shaped and positioned so that its longitudinal direction is aligned with the height direction of the large tank 61A. The liquid level sensor 45 outputs a detection signal to the replenishment control processor 46 when the liquid level of the molten target 27 exceeds a preset target position. The replenishment control processor 46 determines that replenishment of the target material 27A is unnecessary when a detection signal is input, and conversely, determines that replenishment is necessary when the liquid level drops and the input of the detection signal is interrupted.

[0031] When the target 27 is discharged from the nozzle 63, the liquid level of the target 27 in the large tank 61A drops. The replenishment control processor 46 replenishes the target material 27A into the large tank 61A via the replenishment tank 41 and the load lock chamber 43 when it determines that replenishment is necessary to maintain the liquid level of the target 27 in the large tank 61A above the target position.

[0032] 2.2 Operation Figure 3 is the main flowchart showing the operation of the EUV light generation system 11. Figure 4 is a flowchart showing the baking process of the filter 65. Figure 5 is a timing chart corresponding to the flowcharts in Figures 3 and 4. In Figure 5, Figure 5(A) shows the change in temperature T in the tank 61 over time, and Figure 5(B) shows the change in pressure PT in the tank 61 over time. Figure 5(C) shows the change in pressure PC in the chamber 2 over time.

[0033] In step ST100 of Figure 3, when a start command is received, the EUV photogeneration processor 5 starts the EUV photogeneration system 11. Immediately after startup, as shown in Figure 5, the pressure PC in the chamber 2 and the pressure PT in the tank 61 are equal to atmospheric pressure P. atm Similarly, the pressure in the load lock chamber 43 is also atmospheric pressure P. atm That is the case.

[0034] In this state, the EUV light generation processor 5 moves to step ST110 and commands the target supply device 26 to load the target material 27A. Based on this command, the target supply device 26 loads a predetermined amount of target material 27A from the replenishment tank 41 into the empty large tank 61A through the control of the material discharge mechanism 42 and the load lock chamber 43.

[0035] In step ST120, the EUV photogeneration processor 5 instructs the target supply device 26 to supply and exhaust inert gas to the tank 61. This initiates the supply of inert gas from the inert gas supply unit 53 to the tank 61. In parallel with the supply of inert gas, the exhaust device 54 exhausts the inert gas to maintain the pressure PT inside the tank 61. The supply of inert gas reduces the oxygen concentration inside the tank 61. The inert gas is supplied to suppress the formation of oxides through oxidation reactions with residual moisture adhering to the surface of the target material 27A during baking, and to promote the gasification of residual moisture adhering to the filter 65 and the inner wall surface inside the tank 61.

[0036] The EUV light generation system 11 proceeds to step ST130 after step ST120. In step ST130, the filter 65 is baked.

[0037] In step ST130, the vacuuming of tank 61 and chamber 2 as in step ST131 in Figure 4 is initiated. To prevent backflow from chamber 2 to tank 61, the vacuuming of chamber 2 and tank 61 is initiated simultaneously, or the vacuuming of chamber 2 is initiated before that of tank 61. In the example shown in Figure 5, the vacuuming of tank 61 and chamber 2 are initiated simultaneously. The vacuuming of tank 61 is performed by the exhaust device 54 of the target supply device 26. The pressure PT inside tank 61 is equal to atmospheric pressure P. atm The pressure is reduced from to PT1. PT1 is, for example, 1 Pa (see Figure 5). Even after the tank 61 has been evacuated, the supply of inert gas to the tank 61 and the exhaust by the exhaust device 54 continue. The chamber 2 is evacuated by the gas exhaust device 30 under the control of the EUV photogenerating processor 5. As shown in Figure 5, the pressure PC inside the chamber 2 is reduced to atmospheric pressure P atm This process reduces the pressure from PC1 to PC1. PC1 is, for example, 1E-4Pa.

[0038] In tank 61, the gas that escapes to the upstream side of filter 65 is exhausted by exhaust device 54 through exhaust pipe 73 provided in opening 77. Meanwhile, chamber 2 is depressurized by vacuum. Therefore, the gas that escapes to the downstream side of filter 65 flows into chamber 2 through nozzle 63 and is exhausted by gas exhaust device 30. This makes it possible to discharge the moisture that has been vaporized by baking from both the upstream and downstream sides of tank 61. In this state, heating of tank 61 in step ST132 is started.

[0039] In step ST132, the target supply device 26 drives the heater 62 to start heating the tank 61. When heating, for example, only the heater 62 of the large tank 61A is driven. Of course, the heater 62 of the smaller tank 61B may also be driven to heat from both the upstream and downstream sides of the filter 65. When the heating of the tank 61 is started, as shown in FIG. 5, the temperature T of the tank 61 starts to rise from the normal temperature Tr. The temperature T of the tank 61 is heated to T bake up to. The baking temperature T bake is set to a temperature exceeding, for example, the melting point T melt of the target material 27A in order to eliminate as much residual moisture in the tank 61 as possible. When the target material 27A is tin, as shown in FIG. 5, T melt is 232°C, and the baking temperature T bake is set to, for example, 300°C. The baking temperature T bake is determined in consideration of the heat-resistant temperature of the components of the tank 61. That is, if the heat-resistant temperature is T max , the baking temperature T bake is, T melt <T bake <T max set within the range of.

[0040] When the heating of the tank 61 is started, the target supply device 26 monitors the temperature T of the tank 61 in step ST133. When the temperature T reaches the baking temperature T bake = 300°C (Y in step ST133), it proceeds to step ST134 and starts measuring the baking time Bt. The baking time Bt is set to about 24 hours, for example, starting from the time when the tank 61 reaches the baking temperature T bake . By this baking, the residual moisture in the tank 61 is gasified and discharged outside the tank 61.

[0041] When the baking time Bt has elapsed (Y in step ST134), the target supply device 26 proceeds to step ST135 and strengthens the vacuum of the tank 61. In step ST135, the target supply device 26 reduces the pressure PT in the tank 61 from PT1 to PT2 through the exhaust device 54, as shown in Figure 5. PT2 is, for example, 1E-4Pa, similar to PC1 in chamber 2.

[0042] If the target supply device 26 determines in step ST136 that the pressure PT in the tank 61 has reached PT2, it proceeds to step ST137. In step ST137, the target supply device 26 sets the temperature T of the tank 61 to the baking temperature T bake From the melting point T melt The cooling process begins to lower the temperature until it reaches the melting point T. Then, in step ST138, the target supply device 26 checks that the temperature T of the tank 61 is at the melting point T. melt If it is determined that the temperature has dropped to the melting point T, the process determines that step ST130 is complete and returns to step ST140 in Figure 3. After baking, the temperature T of tank 61 is set to the melting point T. melt By lowering the temperature to a certain level (steps ST137 and ST138), the lifespan of the heater 62 can be extended.

[0043] In step ST140, the target supply device 26 starts replenishment control of the target material 27A in preparation for EUV light generation. During replenishment control, the target supply device 26 replenishes the target material 27A so that the liquid level of the molten target 27 in the tank 61 is maintained at the target position. In the comparative example, since there is a step ST110 in which the target material 27A is added before baking in step ST130, the molten target 27 is already present in the tank 61 immediately after baking. Based on the detection signal from the liquid level sensor 45, the target supply device 26 determines whether replenishment is necessary and replenishes the target material 27A if necessary.

[0044] Furthermore, in step ST140, the EUV light generation processor 5 increases the pressure PT in the tank 61 in preparation for EUV light generation. Specifically, the target supply device 26 increases the supply amount of inert gas via the pressure regulator 72, raising the pressure PT in the tank 61 to PT3. PT3 is, for example, 10 MPa. This creates a pressure difference between the tank 61 and the chamber 2, making it possible to discharge the target 27 from the nozzle 63.

[0045] Then, in step ST150, the EUV light generation processor 5 starts ejection control to eject the target 27 as a droplet into the chamber 2 by vibrating the nozzle 63. In step ST160, the EUV light generation processor 5 generates EUV light by injecting pulsed laser light 32 from the laser device 3 into the chamber 2 based on a trigger signal from the external device 6. In step ST170, EUV light generation continues as long as a trigger signal is input from the external device 6.

[0046] 2.3 Challenges In the comparative example target supply device 26, baking is performed with the target material 27A placed in the tank 61. Therefore, the baking temperature T bake The melting point T melt There was a problem in that even when the temperature was set above a certain level, the effect of removing residual moisture could not be improved. This problem will be explained with reference to Figures 6 and 7. Figure 6 shows the state of the tank 61 before heating in baking, and Figure 7 shows the state of the tank 61 after heating. Figures 6(A) and 7(A) are overall views of the tank 61, and Figures 6(B) and 7(B) are enlarged views of a portion centered on the filter 65. For convenience, the heater 62 and liquid level sensor 45, etc., are omitted in Figures 6 and 7.

[0047] The filter 65 has a structure in which, for example, three types of porous materials with different pore sizes, filter layers 65A to 65C, are stacked, with the pore size decreasing towards the nozzle 63. For example, filter layers 65A and 65B are shirasu porous glass filters, and filter layer 65C is a microchannel plate. Also, for example, a gap G is formed between filter layer 65B and filter layer 65C.

[0048] As shown in Figure 6, residual moisture 81 adheres to the inner wall of the tank 61, the gaps in the spherical target material 27A, and the pores inside the filter 65. The introduced target material 27A is deposited on the upper surface of the filter 65. In this state, when the tank 61 is heated, the residual moisture 81 inside the tank 61 gasifies and becomes bubbles. As shown in Figure 7, above the filter 65, the residual moisture 81 adhering to the inner wall of the tank 61 is discharged from the exhaust pipe 73. The residual moisture 81 inside the filter 65 also melts when the temperature T of the tank 61 reaches its melting point T. melt Until it reaches its limit, the material passes through the gaps in the target material 27A, above the filter 65, and is discharged from the exhaust pipe 73.

[0049] However, the temperature T of tank 61 is the melting point T melt When the baking temperature reaches T, the target material 27A melts, and as shown in Figure 7, the molten target 27 covers the top surface of the filter 65. In addition, some of the molten target 27 enters the inside of the filter 65 and clogs the pores of the filter 65. As a result, although the residual moisture 81 inside the filter 65 escapes to the bottom of the filter 65 and is discharged from the nozzle 63, it cannot escape to the top of the filter 65 and is not discharged from the exhaust pipe 73. In other words, in order to improve the discharge effect of residual moisture 81, the baking temperature T bake melting point T melt Even when the temperature is raised above a certain level, in the comparative example, the melted target 27 blocks the discharge path above the filter 65. Therefore, in the comparative example, there was a problem in that the intended discharge effect regarding the discharge of residual moisture 81 could not be obtained.

[0050] 3. Target supply device of the first embodiment 3.1 Configuration The configuration of the target supply device 26 in the first embodiment is the same as that of the target supply device 26 in the comparative example, with only the processing procedure related to baking differing. Therefore, the description of the target supply device 26 will be omitted, and only the differences in the processing procedure will be explained.

[0051] 3.2 Operation Figure 8 is a flowchart showing the baking procedure of the first embodiment. In the baking procedure of the comparative example shown in Figure 3, the target material 27A is added before the baking in step ST130. In contrast, in the procedure of the first embodiment shown in Figure 8, step ST110, in which the target material 27A is added after the baking in step ST130, is performed. Otherwise, it is the same as the comparative example.

[0052] Figure 9 is a timing chart corresponding to the processing procedure shown in Figure 8. The only difference between the timing chart shown in Figure 9 and the timing chart of the comparative example shown in Figure 5 is the order of step ST110; everything else is the same. In Figure 8, steps ST132 to ST135 included in step ST130 are an example of the "first step" relating to the technology of this disclosure, and step ST110 is an example of the "second step" relating to the technology of this disclosure.

[0053] 3.3 Effects Figure 10 is a diagram illustrating the effects of the first embodiment, showing the state of the tank 61 after heating in baking, and corresponds to Figure 7 of the comparative example. Figure 10(A) shows the entire tank 61, similar to Figure 7(A), and Figure 10(B) is a magnified view of a portion of the tank 61 centered on the filter 65, similar to Figure 7(B).

[0054] In the first embodiment, baking is performed before the target material 27A is placed in the tank 61. Therefore, in the first embodiment, the baking temperature T bake The melting point T meltEven when the temperature is raised above this level, the top surface of the filter 65 does not become covered with the molten target 27, as shown in Figure 7 of the comparative example. Furthermore, no portion of the molten target 27 enters the interior of the filter 65 and clogs its pores. As a result, during baking, a drainage path for residual moisture 81 escaping to the top of the filter 65 is ensured. Baking temperature T bake The higher the value, the more the residual moisture 81 is gasified. The first embodiment, compared to the comparative example, has a baking temperature T bake The melting point T melt Raising the temperature above a certain level is highly effective in removing residual moisture 81. As a result, clogging of the nozzle holes caused by the formation of tin oxide due to residual moisture 81 is suppressed compared to the comparative example, and the decrease in the discharge speed of the target 27 is also suppressed.

[0055] 4. Target supply device of the second embodiment 4.1 Configuration The configuration of the target supply device 26 in the second embodiment is the same as that of the comparative example and the target supply device 26 in the first embodiment, with only the processing procedure related to baking differing. Therefore, the description of the target supply device 26 will be omitted, and only the differences in the processing procedure will be explained.

[0056] 4.2 Operation In the processing procedure of the second embodiment, the difference from the first embodiment is that after baking, in which the tank 61 is heated, the target material 27A is added while maintaining the temperature T of the tank 61. That is, in the second embodiment, as shown in Figure 11, in step ST130, there are no steps ST137 and ST138 in which the temperature T of the tank 61 is lowered. Therefore, as shown in the timing chart of Figure 12, the temperature T of the tank 61 is the baking temperature T bake This state is maintained. In the second embodiment, in this state, the loading of the target material 27A in step ST110 in Figure 8 and the subsequent processes related to EUV light generation are performed.

[0057] 4.3 Effects According to the second embodiment, when the temperature T of the tank 61 is the melting point Tmelt Since EUV light generation is performed at a temperature exceeding 5, the risk of poor melting of the target material 27A in the tank 61 can be suppressed more than in the first embodiment.

[0058] 5. Variations In each of the embodiments described above, the target supply device 26 is baked while mounted in the chamber 2 for generating EUV light. However, as shown in Figure 13, the target supply device 26 may also be baked while mounted in a dedicated baking chamber 86. The dedicated baking chamber 86 has, for example, a gas supply device 31 and a gas exhaust device 30, but does not have an EUV focusing mirror 23 and a laser light focusing optical system 22. After baking, the baked target supply device 26 is placed back into the chamber 2. When baking is performed with the target supply device 26 mounted in the chamber 2, as in each of the embodiments described above, the dedicated baking chamber 86 is unnecessary. On the other hand, using the dedicated baking chamber 86 as in the modified example is convenient, for example, when baking multiple target supply devices 26 at once in a single dedicated baking chamber 86.

[0059] 6. Others Figure 14 schematically shows the configuration of the exposure apparatus 6A connected to the EUV light generator 1. The EUV light generator 1 shown in Figure 14 is equipped with a target supply device 26 that has been baked using the processing method of the embodiment described above. In Figure 14, the exposure apparatus 6A, as an external device 6, includes a mask irradiation unit 108 and a workpiece irradiation unit 109. The mask irradiation unit 108 illuminates the mask pattern on the mask table MT via a reflective optical system using EUV light incident from the EUV light generator 1. The workpiece irradiation unit 109 images the EUV light reflected by the mask table MT onto a workpiece (not shown) placed on the workpiece table WT via a reflective optical system. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist. The exposure apparatus 6A exposes the workpiece with EUV light reflecting the mask pattern by synchronously moving the mask table MT and the workpiece table WT in parallel. By transferring a device pattern onto a semiconductor wafer through the exposure process described above, an electronic device can be manufactured.

[0060] Figure 15 schematically shows the configuration of the inspection device 6B connected to the EUV light generator 1. The EUV light generator 1 shown in Figure 15 is equipped with a target supply device 26 that has been baked using the processing method of the embodiment described above. In Figure 15, the inspection device 6B as an external device 6 includes an illumination optical system 103 and a detection optical system 106. The EUV light generator 1 outputs EUV light to the inspection device 6B as an inspection light source. The illumination optical system 103 reflects the EUV light incident from the EUV light generator 1 and irradiates the mask 105 placed on the mask stage 104. The mask 105 here includes mask blanks before a pattern is formed. The detection optical system 106 reflects the EUV light from the illuminated mask 105 and forms an image on the light-receiving surface of the detector 107. The detector 107, having received the EUV light, acquires an image of the mask 105. The detector 107 is, for example, a TDI (time delay integration) camera. The image of the mask 105 obtained through the above process is used to inspect for defects in the mask 105, and the inspection results are used to select a mask suitable for the manufacture of an electronic device. Then, the pattern formed on the selected mask is exposed and transferred onto a photosensitive substrate using the exposure apparatus 6A to manufacture the electronic device.

[0061] Processors such as the EUV photogeneration processor 5, the target generation processor 51, the temperature control processor 55, and the replenishment control processor 46 may be physically configured in hardware form to perform the various processes included in this disclosure. For example, the processor may be a computer including a memory storing control programs that define the various processes, and a processing unit that executes the control programs. The control programs may be stored in a single memory, or they may be divided and stored in multiple physically separate memories, and the various processes may be defined by the control program as a collection of these memories. The processing unit may be a general-purpose processing unit such as a CPU (Central Processing Unit), or a purpose-specific processing unit such as a GPU (Graphical Processing Unit).

[0062] Furthermore, the processor may be programmed in software form to perform the various processes included in this disclosure. For example, the processor may have functions for performing the various processes implemented in a dedicated device such as an ASIC (Application Specific Integrated Circuit) or a programmable device such as an FPGA (Field Programmable Gate Array).

[0063] The various processes included in this disclosure may be performed by one computer, one dedicated device, or one programmable device, or by the cooperation of multiple computers, multiple dedicated devices, or multiple programmable devices located physically separately. The various processes may be performed by at least two combinations of one or more computers, one or more dedicated devices, and one or more programmable devices.

[0064] The above description is intended to be illustrative and not restrictive. It will therefore be apparent to those skilled in the art that modifications can be made to the embodiments of this disclosure without departing from the claims.

[0065] It will also be apparent to those skilled in the art that the embodiments of this disclosure may be used in combination. Unless otherwise specified, terms used herein and throughout the claims should be interpreted as “non-limiting.” For example, terms such as “includes,” “have,” “equip,” and “possess” should be interpreted as “not excluding the existence of components other than those described.” Also, the modifier “one” should be interpreted as “at least one” or “one or more.” Furthermore, the term “at least one of A, B, and C” should be interpreted as “A,” “B,” “C,” “A+B,” “A+C,” “B+C,” or “A+B+C,” and should also be interpreted as including combinations of these with anything other than “A,” “B,” and “C.”

Claims

1. A processing method for a target supply device that supplies a target into a chamber for generating EUV light, The target supply device is A tank capable of accommodating the aforementioned target, A filter housed in the aforementioned tank, A nozzle that communicates with the tank and is capable of discharging the molten target, Equipped with, A first step is to heat the tank to a temperature above the melting point of the target before placing the target into the tank, A second step is to place the target into the tank after the first step, A method for processing a target supply device that includes a target supply device.

2. A processing method for a target supply device according to claim 1, In the first and second steps, the inside of the tank is evacuated.

3. A processing method for a target supply device according to claim 2, Exhaust is released from the aforementioned nozzle.

4. A processing method for a target supply device according to claim 3, The tank has an opening in its wall, and exhaust is also discharged from this opening.

5. A processing method for a target supply device according to claim 1, The target supply device is processed while mounted in the chamber.

6. A processing method for a target supply device according to claim 1, After the first step, the second step is performed after the temperature of the tank has been reduced.

7. A processing method for a target supply device according to claim 1, After the first step, the second step is performed while maintaining the temperature of the tank.

8. A processing method for a target supply device according to claim 1, The target is tin, and the temperature above its melting point is 300°C or less.

9. A processing method for a target supply device according to claim 1, Before the first step, an inert gas is supplied into the tank.

10. A method for manufacturing electronic devices, A chamber that generates EUV light when a supplied target is irradiated with laser light, A target supply device for supplying the target into the chamber, comprising a tank capable of containing the target, a filter housed in the tank, and a nozzle communicating with the tank and capable of discharging the molten target, wherein the target supply device is subjected to a process including a first step of heating the tank to a temperature exceeding the melting point of the target before placing the target into the tank, and a second step of placing the target into the tank after the first step, The EUV light generated by the EUV light generator is output to the exposure device. To manufacture an electronic device, expose a photosensitive substrate to the EUV light in the exposure apparatus. A method for manufacturing electronic devices including

11. A method for manufacturing electronic devices, A chamber that generates EUV light when a supplied target is irradiated with laser light, A target supply device for supplying the target into the chamber, comprising a tank capable of containing the target, a filter housed in the tank, and a nozzle communicating with the tank and capable of discharging the molten target, wherein the target supply device is subjected to a process including a first step of heating the tank to a temperature exceeding the melting point of the target before placing the target into the tank, and a second step of placing the target into the tank after the first step, The EUV light generated by the EUV light generator is irradiated onto the mask to inspect for defects in the mask. Using the results of the above inspection, select a mask. The pattern formed on the selected mask is exposed and transferred onto a photosensitive substrate. A method for manufacturing electronic devices including

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