Light source apparatus, exposure apparatus, and article manufacturing method

Abstract

The invention provides a light source apparatus, an exposure apparatus, and an article manufacturing method. The light source device includes: an element array in which a plurality of light emitting elements are arranged, in which the plurality of light emitting elements include: a first light emitting element; and a second light-emitting element having a temperature characteristic different from a temperature characteristic of the first light-emitting element, the temperature characteristic indicating a relationship between an element temperature and a peak wavelength, and the first light-emitting element and the second light-emitting element are arranged according to a temperature non-uniformity in the element array.

Description

Technical Field

[0001] This disclosure relates to a light source device, an exposure device, and a method for manufacturing an article. Background Technology

[0002] An exposure apparatus is used to transfer a pattern formed in a master print onto a substrate. The apparatus uses light to illuminate the master print via an illumination optics system and projects the image of the pattern onto the substrate via a projection optics system. Traditionally, mercury lamps have been used as the exposure light source, but in recent years, they are expected to be replaced by light-emitting diodes (LEDs) as light-emitting elements. LEDs have high energy efficiency and long lifespan because the time from the flow of current through the circuit configured to control light emission to the stable light output is shorter, thus unlike mercury lamps, they do not require continuous illumination.

[0003] Because the brightness of a single LED is lower than that of a mercury lamp, an LED array consisting of multiple LEDs is required as a light source. The higher the integration level of the LED array or the higher the input power, the greater the total heat generated by the LED array. As the temperature of an LED increases, the following phenomenon occurs: the peak wavelength or dominant wavelength of its emission wavelength characteristics shifts towards a longer wavelength (temperature dependence). Therefore, when temperature non-uniformity occurs among multiple LEDs due to individual control of their current values, a change in the peak wavelength will occur (wavelength non-uniformity).

[0004] Japanese Patent Application Publication No. 2024-035053 discloses a surface-emitting device in which multiple light-emitting elements are arranged in a plane. The surface-emitting device in Japanese Patent Application Publication No. 2024-035053 includes a first light-emitting element arranged on the periphery and a second light-emitting element arranged inside it, and the first and second light-emitting elements output light beams with different peak wavelengths. This reduces color inhomogeneity.

[0005] When multiple LEDs are used as the light source in an exposure apparatus, wavelength non-uniformity caused by temperature dependence affects illumination consistency and resolution. Therefore, it is necessary to reduce wavelength non-uniformity. However, the technology disclosed in Japanese Patent Application Publication No. 2024-035053 cannot reduce wavelength non-uniformity. Summary of the Invention

[0006] This disclosure provides a technique that helps reduce wavelength non-uniformity caused by temperature non-uniformity among multiple light-emitting elements.

[0007] This disclosure provides a light source device in its first aspect, comprising: an element array in which a plurality of light-emitting elements are arranged, wherein the plurality of light-emitting elements includes: a first light-emitting element; and a second light-emitting element having a temperature characteristic different from that of the first light-emitting element, the temperature characteristic indicating the relationship between element temperature and peak wavelength, and the first light-emitting element and the second light-emitting element are arranged according to temperature non-uniformity in the element array.

[0008] This disclosure provides, in a second aspect, an exposure apparatus comprising: an illumination optics system configured to illuminate a master image using light from a light source device defined in the first aspect; and a projection optics system configured to project a pattern of the master image illuminated by the illumination optics system onto a substrate.

[0009] This disclosure provides a method for manufacturing an article in its third aspect, comprising: exposing a substrate using an exposure apparatus defined in the second aspect; and developing the exposed substrate, wherein an article is manufactured from the developed substrate.

[0010] The features of this disclosure will become clear from the following description of embodiments with reference to the accompanying drawings. The following embodiments are described by way of example. Attached Figure Description

[0011] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present disclosure and, together with the textual description, serve to explain the principles of the embodiments.

[0012] Figure 1 It is a diagram showing the arrangement of the light source device;

[0013] Figure 2 It is a graph showing the temperature-peak wavelength characteristics of the light-emitting element;

[0014] Figure 3 It is a diagram used to illustrate the arrangement of multiple light-emitting elements in an element array;

[0015] Figure 4A and Figure 4B It is a diagram showing the arrangement of the component array;

[0016] Figure 5 It is a diagram used to illustrate the heat sink flow path and the arrangement of multiple light-emitting elements in a component array; and

[0017] Figure 6 This is a diagram showing the arrangement of the exposure apparatus. Detailed Implementation

[0018] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claims. Multiple features are described in the embodiments, but not all of these features are necessary, and these features can be appropriately combined. Furthermore, in the drawings, the same or similar constructions are given the same reference numerals, and redundant descriptions thereof will be omitted.

[0019] <First Embodiment>

[0020] Figure 1 This diagram illustrates the arrangement of the light source device 10 according to the first embodiment. The light source device 10 may include: an element array 3 of a plurality of light-emitting elements 1 arranged in a matrix, a power supply 4, and a controller 7. Each of the plurality of light-emitting elements 1 is formed by an LED. The light emission amount of the element array 3 in this embodiment is variable.

[0021] Since the radiant energy of a single light-emitting element 1 is less than that of a mercury lamp, multiple light-emitting elements 1 are required. These multiple light-emitting elements 1 are arranged in a matrix. The number of light-emitting elements 1 can be, for example, approximately 1000, but is not limited to a specific number. Figure 1 As shown, for convenience, multiple light-emitting elements 1 are arranged in a 6×6 matrix. Here, the horizontal direction corresponds to rows, and the vertical direction corresponds to columns. Figure 1 In this configuration, multiple light-emitting elements 1 are arranged in a square matrix, but are not limited to this arrangement. For example, multiple light-emitting elements 1 can be arranged in a zigzag pattern. Each of the multiple light-emitting elements 1 can be a UV-LED (ultraviolet light-emitting diode) element that emits ultraviolet light. If each of the multiple light-emitting elements 1 is a UV-LED element, the nominal emission peak wavelength is, for example, 365nm, 385nm, 405nm, etc.

[0022] Multiple light-emitting elements 1 are interconnected via leads 2 to form a circuit. Figure 1 In the example shown, the light-emitting elements 1 in each row are connected in series via leads 2, and each row is connected in parallel to the power supply 4. When current flows through the circuit, each light-emitting element 1 outputs light. Figure 1 In the example shown, when current is supplied from the power supply 4 to the light-emitting elements 1 in each column via lead 2, each light-emitting element 1 emits light. At this time, each of the multiple light-emitting elements 1 may generate heat. Typically, the package type of the element array 3 with this arrangement is also called Chip On Board (COB). COB has the advantage of being able to integrate a large number of light-emitting elements (LED chips) and thus provide a large amount of light.

[0023] The controller 7 can be formed by a general-purpose or dedicated computer installed with a program, or formed by a combination of all or some of these components. The controller 7 can include, for example, a processor 8 and a memory 9. The processor 8 determines the current values supplied to the respective rows of the element array 3 and drives the power supply 4. In Figure 1 the arrangement shown, the power supply 4 cannot drive the plurality of light-emitting elements 1 in the element array 3 individually, but can drive the plurality of light-emitting elements 1 to emit light row by row.

[0024] The LED used as a light-emitting element has temperature dependence, wherein the peak wavelength or main wavelength of the light emitted from the LED changes according to the element temperature of the LED. The plurality of light-emitting elements 1 can include a first light-emitting element A, a second light-emitting element B, and a third light-emitting element C having different temperature characteristics (temperature-peak wavelength characteristics), which indicate the relationship between the element temperature and the peak wavelength. Figure 2 is a graph showing the temperature-peak wavelength characteristics of the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C. In Figure 2 it, the abscissa represents the temperature of the light-emitting element (LED), and the ordinate represents the peak wavelength of the light-emitting element. According to Figure 2 , the peak wavelengths of the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C at a reference temperature (e.g., 23 °C) are λA, λB, and λC, respectively.

[0025] Referring to Figure 3 , an example of the arrangement of the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C in the element array 3 will be described. Figure 3 is a diagram schematically showing the light-emitting surface in the element array 3. The element array 3 can have: a central region 31 including the center of the light-emitting surface of the element array 3, a first peripheral region 32 surrounding the central region 31, and a second peripheral region 33 surrounding the first peripheral region 32. The second peripheral region 33 is located at the outermost periphery of the element array 3. Note that only one peripheral region surrounding the central region 31 can be defined without distinguishing between the first peripheral region 32 and the second peripheral region 33. The first peripheral region 32 can also be divided into multiple regions.

[0026] According to Figure 2 the characteristics shown, when current flows through the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C (during power-on), the temperatures (average temperatures) of the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C are TA, TB, and TC, respectively. Note that TA < TB < TC. In other words, if current flows when the temperatures of the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C are TA, TB, and TC, respectively, the light beams output from the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C have the same wavelength.

[0027] The element array 3, which integrates light-emitting elements, exhibits the following trend: the temperature of the region surrounded by more heat-generating elements (light-emitting elements) is higher. For example, the temperature of the central region 31 is higher than that of the first peripheral region 32, and the temperature of the first peripheral region 32 is higher than that of the second peripheral region 33. In this way, when temperature non-uniformity (temperature distribution) occurs in the element array 3, wavelength non-uniformity may occur among the multiple light-emitting elements.

[0028] To prevent this, in this embodiment, the light-emitting elements are arranged according to the temperature non-uniformity (temperature distribution) in the element array 3. That is, light-emitting elements with longer peak wavelengths at the reference temperature are arranged in the low-temperature region, while light-emitting elements with shorter peak wavelengths at the reference temperature are arranged in the high-temperature region. More specifically, as... Figure 3 As shown, a first light-emitting element A, having a peak wavelength λA at a reference temperature, is arranged in the second peripheral region 33. A second light-emitting element B, having a peak wavelength λB at the reference temperature, is arranged in the first peripheral region 32. Furthermore, a third light-emitting element C, having a peak wavelength λC at the reference temperature, is arranged in the central region 31. Thus, the peak wavelengths of the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C can be made consistent during energization.

[0029] In this manner, in the example above, among the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C, the third light-emitting element C, which has the shortest peak wavelength at the reference temperature, is arranged in the central region 31. The second light-emitting element B, which has the second shortest peak wavelength at the reference temperature, is arranged in the first peripheral region 32, while the first light-emitting element A, which has the longest peak wavelength at the reference temperature, is arranged in the second peripheral region 33.

[0030] Note that if the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C are UV-LEDs, they are preferably configured to have the following temperature-wavelength characteristics: the peak wavelength during energization falls within a predetermined allowable range (e.g., 366 nm ± 2 nm). Alternatively, the predetermined allowable range is more preferably, for example, 366 nm ± 1 nm.

[0031] In the example above, the following situation is described: the multiple light-emitting elements 1 include three light-emitting elements with different temperature characteristics. Conversely, when the multiple light-emitting elements 1 include only two light-emitting elements with different temperature characteristics (e.g., first light-emitting element A and second light-emitting element B), only the central region and the peripheral region are defined, without distinguishing between the first peripheral region 32 and the second peripheral region 33. In this case, one of the first light-emitting elements A and the second light-emitting element B, which has a shorter peak wavelength at the reference temperature, is arranged in the central region, while the other is arranged in the peripheral region.

[0032] Using the above arrangement, even when there is temperature non-uniformity in the element array 3 during power-on, wavelength non-uniformity between multiple light-emitting elements can be reduced.

[0033] <Second Embodiment>

[0034] Figure 4A and Figure 4B This is a diagram showing the arrangement of the element array 3 according to the second embodiment. Figure 4A This is a schematic diagram of the cross-section of element array 3 when viewed from the x-direction, and Figure 4B This is a schematic diagram of the element array 3 when viewed from the z-direction. Multiple light-emitting elements 1 are arranged in a matrix along the x and y directions on the base 21.

[0035] The half-angle of light emitted from the multiple light-emitting elements 1 is approximately 60 to 70°. Considering that the numerical aperture NA of a typical flat panel display projection optics system is approximately 0.1 (equivalent to an angle of approximately 5.7°), this is a very large angular distribution. Therefore, in order to capture the light flux emitted from the multiple light-emitting elements 1 without loss through the downstream optical system, a condenser 23 can be arranged directly above each of the multiple light-emitting elements 1 to collimate the emitted light flux. The condenser 23 is equipped with a collimating lens corresponding to the light-emitting element 1. Figure 4B In the diagram, the intersection of the alternating long and short dashed lines represents the optical axes of each collimating lens included in the condenser 23.

[0036] In UV-LED elements, only about 30% to 50% of the input power is usable as the desired light, and the remainder is converted into heat. Therefore, a cooler 24 is provided to suppress temperature variations among the multiple light-emitting elements 1. The cooler 24 is, for example, a liquid-cooled heat sink. In this case, the cooler 24 has a heat sink flow path arranged to flow past each of the multiple light-emitting elements 1, and coolant flows through this heat sink flow path. Coolant adjusted to a predetermined temperature is supplied to the heat sink flow path from the supply unit 25. As the coolant flows through the heat sink flow path, it absorbs the heat transferred from the light-emitting elements 1 via the base 21, thereby cooling the light-emitting elements 1. The coolant that has absorbed heat from the light-emitting elements 1 is recovered via a recovery unit 26. The recovered coolant is cooled by an adjustment unit (not shown) and supplied back to the cooler 24.

[0037] Cooling-related parameters (cooling conditions) include the coolant flow rate and the coolant temperature. Increasing the coolant flow rate or decreasing the coolant temperature improves cooling performance and allows for the removal of more heat from the light-emitting element 1. Typically, the coolant temperature is set close to the ambient temperature (room temperature) of the light source device 10. Since the room temperature in cleanrooms used for manufacturing semiconductors / FPDs is typically around 22°C to 24°C, this temperature range can include either ambient temperature or room temperature.

[0038] Figure 5 An example of a heat sink flow path 41 forming a cooler 24 is shown. The heat sink flow path 41 is arranged to meander near each of the plurality of light-emitting elements 1, for example, from the upper left position to the lower left position in the element array 3. One end of the heat sink flow path 41 at the upper left position in the element array 3 is fluidly connected to the supply unit 25, and the other end of the heat sink flow path 41 at the lower left position in the element array 3 is fluidly connected to the recovery unit 26. Figure 5 In the heat sink flow path 41 shown, the area comprising the top two rows of a 6×6 matrix of multiple light-emitting elements 1 is defined as the upstream region 51, the area comprising the bottom two rows is defined as the downstream region 53, and the area comprising the middle two rows between the upstream and downstream regions is defined as the midstream region 52. Note that only the upstream region 51 and the downstream region 53 may be defined, without the midstream region 52. As the coolant flows from the upstream region 51 to the midstream region 52 and then to the downstream region 53, the temperature of the coolant flowing through the heat sink flow path 41 increases.

[0039] according to Figure 2 As shown, during energization, the temperature of the first light-emitting element A is TA, the temperature of the second light-emitting element B is TB (above TA), and the temperature of the third light-emitting element C is TC (above TB). Therefore, in the second embodiment, as... Figure 5As shown, a first light-emitting element A, having a peak wavelength λA at a reference temperature, is arranged in the upstream region 51. A second light-emitting element B, having a peak wavelength λB at the reference temperature, is arranged in the midstream region 52. Furthermore, a third light-emitting element C, having a peak wavelength λC at the reference temperature, is arranged in the downstream region 53. Thus, the peak wavelengths of the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C can be made consistent during energization.

[0040] In this way, in the example above, among the first light-emitting element A, the second light-emitting element B, and the third light-emitting element C, the light-emitting element with the longest peak wavelength at the reference temperature is arranged in the upstream region of the flow path, the light-emitting element with the second longest peak wavelength is arranged in the midstream region of the flow path, and the light-emitting element with the shortest peak wavelength is arranged in the downstream region of the flow path.

[0041] In the example above, a situation is described where the plurality of light-emitting elements 1 includes three light-emitting elements having different temperature characteristics from each other. Conversely, when the plurality of light-emitting elements 1 includes only two light-emitting elements (e.g., first light-emitting element A and second light-emitting element B) having different temperature characteristics from each other, the matrix of the plurality of light-emitting elements 1 is defined only by two flow regions (i.e., upstream region and downstream region). In this case, one of the first light-emitting elements A and the second light-emitting element B, which has a longer peak wavelength at the reference temperature, is arranged on the upstream side of the flow path, while the other is arranged on the downstream side of the flow path.

[0042] Using the above arrangement, even when there is temperature non-uniformity (temperature distribution) in the element array 3 due to the temperature change of the coolant, the wavelength non-uniformity between multiple light-emitting elements can be reduced.

[0043] <Third Embodiment>

[0044] Figure 6The arrangement of an exposure apparatus 400 according to a third embodiment is shown. The exposure apparatus 400 is an exposure apparatus using a light source device 10 according to the first or second embodiment described above. The exposure apparatus 400 may include, for example, a light source device 10, a shutter device 420, an illumination optics system 430, a master plate holder 440, a projection optics system 450, and a substrate holder 460. The illumination optics system 430 may include an i-line band filter 432. The master plate holder 440 holds the master plate 442. The master plate holder 440 may be positioned by a master plate positioning mechanism (not shown), thereby positioning the master plate 442. The substrate holder 460 holds the substrate 462. The substrate 462, to which resist (photosensitive material) has been applied by a resist application device, is supplied to the exposure apparatus 400. The substrate holder 460 may be positioned by a substrate positioning mechanism (not shown), thereby positioning the substrate 462. The shutter device 420 is arranged such that it can block the light flux in the optical path between the light source device 10 and the original holder 440. Blocking the light flux can be achieved by stopping the emission of light from the LEDs in the light source device 10. The illumination optics system 430 illuminates the original 442 with light from the light source device 10. The projection optics system 450 projects the pattern of the original 442 illuminated by the illumination optics system 430 onto a substrate 462, thereby exposing the substrate 462. Using this exposure, a latent image pattern is formed in the resist applied to the substrate 462. This latent image pattern is developed by a developing apparatus (not shown), thereby forming a resist pattern on the substrate 462.

[0045] The projection optical system 450 uses an imaging optical system. Therefore, if the peak wavelength of the multiple light-emitting elements 1 changes in the light source device 10, the pattern imaging performance on the substrate 462 deteriorates because the refractive index of the lens changes according to the wavelength. Furthermore, the i-band filter 432 cuts off the peak wavelength of the light from the light source device 10 to a wavelength width according to the lens performance. Therefore, if wavelength inhomogeneity occurs in the light source device, the peak wavelength of the composite light diffuses, and the illuminance decreases. For example, when the half-width of the i-band filter 432 is 10 nm, if a 1 nm wavelength shift occurs, approximately 10% of the light is cut off.

[0046] To prevent degradation of the imaging performance of the projection optical system 450, the wavelength variation among the multiple light-emitting elements 1 in the light source device is preferably less than ±1 nm. The light source device 10 uses LEDs instead of UV lamps. Therefore, in an optical system designed for UV lamps, considering the wavelength of the UV lamp, the wavelength during power-on is preferably within the range of 366 nm ± 1 nm.

[0047] By using the light source device according to the first or second embodiment described above, excellent resolution and illuminance can be achieved.

[0048] <Example of Article Manufacturing Method>

[0049] The article manufacturing method according to embodiments of this disclosure is applicable to the manufacture of articles, such as micro-devices or elements having microstructures, like semiconductor devices. The article manufacturing method according to this embodiment includes a step of forming a latent pattern in a photosensitizer applied to a substrate using the aforementioned exposure apparatus (the step of exposing the substrate), and a step of developing the substrate on which the latent pattern was formed in the previous step. The manufacturing method also includes other known steps (oxidation, film formation, deposition, doping, planarization, etching, resist removal, dicing, bonding, encapsulation, etc.). The article manufacturing method of this embodiment is superior to conventional methods in at least one aspect of article performance, quality, productivity, and production cost.

[0050] According to this disclosure, a technique is provided that is beneficial for reducing wavelength non-uniformity caused by temperature non-uniformity among multiple light-emitting elements.

[0051] While this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be interpreted in the broadest possible sense to cover all such variations and equivalent structures and functions.

Claims

1. A light source apparatus comprising: an element array in which a plurality of light emitting elements are arranged, wherein the plurality of light emitting elements include: a first light emitting element; and a second light emitting element having a temperature characteristic different from that of the first light emitting element, the temperature characteristic indicating a relationship between an element temperature and a peak wavelength, and the first light emitting element and the second light emitting element are arranged in accordance with temperature inhomogeneity in the element array.

2. The light source apparatus according to claim 1, wherein the element array includes a central region and a peripheral region surrounding the central region, the central region including a center of a light emitting surface of the element array, and one of the first light emitting element and the second light emitting element having a shorter peak wavelength at a reference temperature is disposed in the central region, and the other is disposed in the peripheral region.

3. The light source apparatus according to claim 1, wherein the plurality of light emitting elements further include a third light emitting element having a temperature characteristic different from that of each of the first light emitting element and the second light emitting element, the element array has a central region, a first peripheral region surrounding the central region, and a second peripheral region surrounding the first peripheral region, the central region including a center of a light emitting surface of the element array, and among the first light emitting element, the second light emitting element, and the third light emitting element, a light emitting element having a shortest peak wavelength at a reference temperature is disposed in the central region, a light emitting element having a second shortest peak wavelength at the reference temperature is disposed in the first peripheral region, and a light emitting element having a longest peak wavelength at the reference temperature is disposed in the second peripheral region.

4. The light source apparatus according to claim 1, further comprising: a cooler having a flow path arranged so as to flow through a vicinity of each of the plurality of light emitting elements, and a coolant flowing through the flow path, wherein one of the first light emitting element and the second light emitting element having a longer peak wavelength at a reference temperature is disposed on an upstream side of the flow path, and the other is disposed on a downstream side of the flow path.

5. The light source apparatus according to claim 1, further comprising: a cooler having a flow path arranged so as to flow through a vicinity of each of the plurality of light emitting elements, and a coolant flowing through the flow path, wherein the plurality of light emitting elements further include a third light emitting element having a temperature characteristic different from that of each of the first light emitting element and the second light emitting element, and Among the first light emitting element, the second light emitting element, and the third light emitting element, the light emitting element having the longest peak wavelength at a reference temperature is arranged in an upstream region of the flow path, the light emitting element having the second longest peak wavelength at a reference temperature is arranged in a middle region of the flow path, and the light emitting element having the shortest peak wavelength at a reference temperature is arranged in a downstream region of the flow path.

6. The light source device according to claim 1, wherein In a state where the first light emitting element and the second light emitting element are arranged in accordance with temperature unevenness in the element array, a difference between a peak wavelength of the first light emitting element and a peak wavelength of the second light emitting element during energization falls within a predetermined allowable range.

7. The light source device according to claim 6, wherein Each of the plurality of light emitting elements is a UV-LED element that emits ultraviolet light, and A wavelength variation between the plurality of light emitting elements is ±1 nm or less.

8. The light source device according to claim 6, wherein Each of the plurality of light emitting elements is a UV-LED element that emits ultraviolet light, and The predetermined allowable range is a range of 366 nm ± 2 nm.

9. The light source device according to claim 7, wherein The predetermined allowable range is a range of 366 nm ± 1 nm.

10. An exposure apparatus comprising: an illumination optical system configured to irradiate a original plate with light from the light source device defined in any one of claims 1 to 9; and a projection optical system configured to project a pattern of the original plate irradiated by the illumination optical system onto a substrate.

11. An article manufacturing method comprising: exposing a substrate using the exposure apparatus defined in claim 10; and developing the exposed substrate, wherein an article is manufactured from the developed substrate.

12. The article manufacturing method according to claim 11, wherein the substrate is a substrate for manufacturing a semiconductor device.

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