Exposure apparatus and method for manufacturing articles

Abstract

This technology offers advantages in achieving both anti-fogging performance of the optical elements of a projection optical system and measurement accuracy of the substrate position. [Solution] An exposure apparatus for exposing a substrate includes a projection optical system that projects an image of the pattern of a master plate onto the substrate, a supply unit that supplies gas to the space between the projection optical system and the substrate, a measurement unit that measures the position of the substrate, and a control unit that controls the supply of gas by the supply unit so as to change the flow velocity of the gas passing between the measurement unit and the substrate.

Description

Technical Field

[0001] The present invention relates to an exposure apparatus and a method for manufacturing an article.

Background Art

[0002] As one of the apparatuses used in the lithography process in the manufacturing process of liquid crystal panels and semiconductor devices, there is an exposure apparatus that projects the pattern of a reticle illuminated by an illumination optical system onto a substrate to expose the substrate. A resist is applied to the substrate (wafer) used in the exposure apparatus, and contaminants can be generated from the resist by exposure. Such contaminants cloud the optical elements by reacting with impurities such as acids, bases, and organics in the surrounding atmosphere, or impurities such as acids, bases, and organics in the film of the optical elements around the wafer. In particular, the optical element disposed at the lowermost end of the projection optical system is disposed directly above the wafer, so the clouding phenomenon is likely to occur.

[0003] Also, the contaminants that cloud the optical element disposed at the lowermost end of the projection optical system do not come only from the resist. Around the projection optical system, there are drive systems and structures using grease and adhesives that are likely to generate contaminants, or resins and rubbers that are likely to generate contaminants in the parts themselves. The contaminants generated from these are carried by the air conditioning to the vicinity of the wafer and reach the optical element disposed at the lowermost end of the projection optical system, clouding the optical element.

[0004] Clouding of the optical element can cause insufficient exposure amount, uneven illuminance, flare, etc., and can reduce the transfer accuracy of the reticle pattern onto the wafer. Therefore, an air nozzle for blowing off contaminants may be disposed near the optical element of the exposure apparatus. When blowing off contaminants with an air nozzle, generally, it is advantageous to flow a gas at a high flow rate and a large flow rate throughout the space between the wafer and the optical element. For such a gas, for example, clean air, clean dry air, nitrogen gas, etc. are used.

[0005] Patent Document 1 describes a method for flowing a substantially larger flow rate between a wafer and an optical element than the supply flow rate. Specifically, Patent Document 1 describes providing a gas supply port near the projection optical system and arranging a guide plate to guide the gas blown out from the gas supply port between the wafer and the optical element. This guide plate draws in gas from a clean area, straightens the flow, and guides the gas between the wafer and the optical element, allowing the gas to flow at a high velocity and large flow rate.

[0006] Patent Document 2 describes a technique for adjusting the gas flow rate based on the distribution of clouding on the optical element, thereby flowing the maximum possible amount of gas, because simply flowing a high-velocity, high-flow gas between the wafer and the optical element can actually cause contaminants to be drawn in. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-011815 [Patent Document 2] Japanese Patent Publication No. 2023-148841 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, simply flowing gas at high velocity and high flow rate to protect optical elements from contaminants will also flow gas at high velocity and high flow rate into the measurement system downstream of the optical elements. As a result, air fluctuations may occur in the optical path of the measurement system, potentially reducing measurement accuracy. In addition, the high-velocity gas may strike the structure of the measurement system, causing the structure itself to vibrate slightly, which could also reduce measurement accuracy.

[0009] This invention provides a technology that is advantageous in achieving both anti-fogging performance of the optical elements of a projection optical system and measurement accuracy of the substrate position. [Means for solving the problem]

[0010] According to one aspect of the present invention, an exposure apparatus for exposing a substrate is provided, comprising: a projection optical system for projecting an image of a pattern of a master plate onto the substrate; a supply unit for supplying gas to the space between the projection optical system and the substrate; a measurement unit for measuring the position of the substrate; and a control unit for controlling the supply of gas by the supply unit so as to change the flow velocity of the gas passing between the measurement unit and the substrate. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a technology that is advantageous in achieving both anti-fogging performance of the optical elements of a projection optical system and measurement accuracy of the substrate position. [Brief explanation of the drawing]

[0012] [Figure 1] A diagram showing the configuration of an exposure apparatus. [Figure 2] A diagram showing the configuration of an exposure apparatus without a rectifier plate. [Figure 3] A diagram illustrating the size of the gas supply unit. [Figure 4] A diagram illustrating the control of the substrate stage in the exposure sequence. [Figure 5] A diagram showing the configuration of an exposure apparatus equipped with a temperature sensor. [Figure 6] A diagram showing the configuration of an exposure apparatus equipped with an exhaust unit and an exhaust flow rate adjustment unit. [Figure 7] A diagram illustrating the placement of the exhaust section. [Figure 8] A diagram showing the configuration of an exposure apparatus equipped with multiple flow rate adjustment units. [Figure 9] A diagram showing the configuration of an exposure apparatus equipped with multiple flow rate adjustment units. [Figure 10] A diagram showing the overall configuration of the exposure apparatus. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are given the same reference numerals, and duplicate explanations are omitted.

[0014] FIG. 1 is a schematic view of an exposure apparatus 100 according to an embodiment. In this specification and the drawings, directions are indicated in an XYZ coordinate system with the horizontal plane as the XY plane. Generally, a substrate W to be exposed is placed on a substrate stage 4 such that its surface is parallel to the horizontal plane (XY plane). Therefore, hereinafter, directions orthogonal to each other within the plane along the surface of the substrate W are taken as the X-axis and the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is taken as the Z-axis. Further, hereinafter, directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are referred to as the X-direction, Y-direction, and Z-direction, respectively.

[0015] <First Embodiment> In FIG. 1, the exposure apparatus 100 may include a projection optical system 2, a substrate stage 4, a measurement unit 7, and a control unit 23. The projection optical system 2 may include an optical element 3 located at its lowermost end. The exposure apparatus 100 may further include a gas supply unit 10 (supply unit). The gas supply unit 10 supplies a first gas 40 to the space between the projection optical system 2 (optical element 3 thereof) and the substrate W (wafer) held by the substrate stage 4. The gas supply unit 10 may include a gas supply port 11 and a flow rate adjustment unit 20 that adjusts the supply flow rate of the first gas 40 from the gas supply port 11. The gas supply unit 10 may be fixed to the projection optical system 2 or may be fixed to a base (not shown) in the vicinity thereof.

[0016] The measurement unit 7 is configured to emit measurement light toward the substrate stage 4 and measure the position of the substrate stage 4 or the substrate W. The measurement unit 7 can be, for example, an OAS (Off-axis Alignment Scope) for measuring marks on the substrate. In order to improve the measurement accuracy by the measurement unit 7, it is required to keep the temperature, pressure, and humidity of the atmosphere through which the measurement light passes constant. The measurement unit 7 is arranged at any position where the first gas 40 flows. In FIG. 1, the measurement unit 7 is arranged downstream of the projection optical system 2 with respect to the airflow of the first gas 40, but it may be arranged upstream of the projection optical system 7.

[0017] The gas supply unit 10 may further include a flow rectifying plate 12. The partition wall of the gas supply port 11 and the flow rectifying plate 12 form a first opening 13a at a position farther from the exposure center, and the projection optical system 2 and the flow rectifying plate 12 form a second opening 13b at a position closer to the exposure center. The flow rectifying plate 12 is for aligning the airflow around the gas supply unit 10 in a certain direction, preventing the entrainment of surrounding gas, or aligning the direction of entrainment of surrounding gas, but it is not essential. For example, as shown in FIG. 2, as an example without the flow rectifying plate 12, the lower wall of the gas supply port 11 of the gas supply unit 10 may be extended between the optical element 3 and the substrate stage 4 so as to serve as a flow rectifying plate. Also, in FIGS. 1 and 2, the gas supply port 11 is arranged so as to be located below the projection optical system 2, but the gas supply port 11 may be arranged outside the projection optical system 2, and from that location, the first gas 40 may be configured to be supplied between the optical element 3 and the substrate stage 4.

[0018] The control unit 23 is constituted by, for example, a computer including a CPU (processor) and a memory, is electrically connected to each part in the apparatus, and controls each part in an overall manner. Note that the control unit 23 may be installed at a location different from the room (for example, a clean room) where the exposure apparatus 100 is installed and may be realized as a server apparatus connected to the exposure apparatus 100 via a wired or wireless network.

[0019] Figure 3 shows the gas supply unit 10 as viewed from below the projection optical system 2 (the rectifier plate 12 is not shown). As shown in Figure 3, it is preferable that the size of the gas supply port 11 in the direction perpendicular to the blowing direction of the first gas 40 (X direction) is larger than the irradiation range 61, which is the range in which the laser light is irradiated onto the substrate W via the projection optical system 2. It is even more preferable that this size is larger than the range 62 in which the laser light passes over the first surface 31 of the optical element 3 on the substrate W side.

[0020] The first gas 40 is preferably a clean gas so as not to adversely affect the clouding of the optical element 3. A clean gas means a gas with few impurities such as acids, bases, and organic substances. It is even more preferable that the gas is clean air, which is air from which impurities such as acids, bases, and organic substances have been removed; clean dry air, which is clean air that has been dried; or an inert gas such as nitrogen gas.

[0021] The first gas 40 can be supplied from an air conditioning unit 26, as shown in Figure 10, which will be described later. The air conditioning unit 26 may be located inside or outside the exposure apparatus. The air conditioning unit 26 is equipped with a temperature controller that can adjust the temperature of the first gas 40, and the temperature of the first gas 40 is set to match the ambient (air) temperature between the projection optical system 2 and the substrate stage 4. Alternatively, considering that heat is lost in the piping before reaching the area between the projection optical system 2 and the substrate stage 4, the temperature of the first gas 40 may be set to a temperature slightly higher than the ambient (air) temperature between the projection optical system 2 and the substrate stage 4. An air conditioning unit 5 is located in the space where the gas supply unit 10 is located, and in addition to the first gas 40, a second gas 41 is supplied. At least a portion of the second gas 41 flows between the optical element 3 and the substrate stage 4.

[0022] The room housing the exposure apparatus 100 is also equipped with an air conditioning system 5. The second gas 41 blown out from the air conditioning system 5 is kept clean by a chemical filter 6 located inside the air conditioning system 5. A clean state for the second gas 41 means that it is kept in a state with few impurities such as acids, bases, and organic matter by the chemical filter 6. However, the chemical filter 6 deteriorates with long-term use, so it cannot keep the second gas 41 clean semi-permanently. Furthermore, if the source of the second gas 41 in the air conditioning system 5 is the air from the cleanroom housing the exposure apparatus 100, the cleanliness of the second gas 41 may depend on the cleanliness of the cleanroom, even after passing through the chemical filter 6. In addition, if the cleanliness of the cleanroom is poor, the deterioration rate of the chemical filter 6 may be accelerated.

[0023] By the time the second gas 41 passes between the optical element 3 and the substrate stage 4, impurities may be mixed into the second gas 41. These impurities could be acids, bases, or organic substances generated from adhesives or greases used in actuators, guides, bearings, etc., for driving the substrate stage 4. Alternatively, the impurities could be acids, bases, or organic substances generated from resins, rubbers, etc., of structures, mounted components, etc. For this reason, it may be difficult to maintain a clean state of the second gas 41. Furthermore, in a configuration where the gas in the space where the gas supply unit 10 is located is circulated and the gas that passes through the chemical filter 6 becomes the second gas 41, the deterioration rate of the chemical filter 6 may be further accelerated due to the influence of contaminants 50 generated from the resist of the substrate W.

[0024] Thus, since the second gas 41 ceases to be clean, one of the roles of the gas supply unit 10 is to prevent the second gas 41 from reaching the optical element 3.

[0025] Next, we will explain the case when the exposure apparatus 100 irradiates the substrate W with laser light via the projection optical system 2 (i.e., when the substrate W is exposed). When the substrate W is irradiated with laser light, contaminants 50 are generated from the substrate W on which the resist is coated. Contaminants 50 are impurities such as acids, bases, and organic matter. The contaminants 50 have components that are generated with a vertically upward velocity, and these reach the optical element 3 via the second gas 41, causing the optical element 3 to become cloudy. Another role of the gas supply unit 10 is to prevent this, and for this purpose, the first gas 40 is blown out to prevent the contaminants 50 from reaching the optical element 3.

[0026] As described above, the factors that cause the optical element 3 to become cloudy can be broadly divided into two categories. One is caused by contaminants 50, which come from directly below the optical element 3. The other is caused by contaminants other than contaminants 50 (impurities), which are carried by the second gas 41 and come from the surrounding area of ​​the optical element 3.

[0027] In this situation, the flow rate of the first gas 40 supplied from the gas supply unit 10 is usually set to a higher flow rate than that of the second gas 41 so that the contaminants 50 can be blown away. This is because the fogging of the optical element 3 tends to progress faster when caused by contaminants 50 than when caused by the second gas 41. When the flow rate adjustment unit 20 adjusts the first gas 40 to a high flow rate, the airflow directly below the measurement unit 7, which is downstream in the direction of the airflow, that is, in the region through which the measurement light from the measurement unit 7 passes, also becomes high speed.

[0028] However, if the airflow in the region through which the measurement light from the measurement unit 7 passes becomes high speed, turbulence is more likely to occur, making it easier to entrain surrounding air and potentially making it difficult to maintain constant temperature, pressure, and humidity. In other words, it may become difficult to maintain high accuracy in the measurement of the measurement unit 7. Furthermore, if the airflow in this region becomes high speed, it may affect the structure of the measurement unit 7 itself with vibrations. For example, the structure of the measurement unit 7 itself may vibrate in the following cases: (a) When the measuring unit 7 itself is vulnerable to external forces and prone to vibration. (b) When a thin cover is provided on the lower surface of the measuring unit 7, and the thin cover vibrates due to the airflow. (c) When there is a protrusion in the structure of the measurement unit 7, and the high-velocity first gas 40 directly hits it, causing it to vibrate.

[0029] In this way, when the structure of the measurement unit 7 itself vibrates, the measurement light also vibrates. As a result, high-precision measurement may become difficult with the measurement unit 7.

[0030] In this embodiment, in order to maintain high-precision measurement by the measurement unit 7, the flow rate of the first gas 40 is adjusted based on the position of the substrate stage 4 and the exposure sequence. The general flow of the exposure sequence in this embodiment is shown below. (a) Wafer load: The substrate W is removed from the substrate storage section and mounted on the substrate stage 4. (b) Focus adjustment and reference position adjustment: Focus adjustment is performed by controlling the Z position of the substrate stage 4 below the projection optical system 2, and then a correction value for the reference value (baseline) representing the distance between the projection optical system 2 and the measurement unit 7 is determined. (c) Measurement: Measurement light 9 is emitted from the measurement unit 7, and the substrate stage 4 is moved below the measurement unit 7 to measure the reference position of the substrate stage 4 and each reference position of the substrate W (at this time, the positional relationship is as shown in Figure 4(b)). (d) Exposure: Exposure light is emitted from the projection optical system 2, and the substrate stage 4 is scanned and moved below the projection optical system 2 to expose the substrate W (at this time, the positional relationship is as shown in Figure 4(a)). (e) Wafer unloading: Remove the substrate W from the substrate stage 4 and return the substrate W to the substrate storage unit. Once (e) is completed, the process may be repeated from (a). The sequence from (a) to (e) may also be performed individually. For example, only (c) measurement may be performed.

[0031] To improve the measurement accuracy of the measurement unit 7, the flow rate adjustment unit 20 adjusts the gas flow rate to satisfy, for example, the following two conditions. (1)(d) The flow rate of the first gas 40 supplied from the gas supply unit 10 during exposure (first flow rate) is equal to or greater than the flow rate in other sequences. (2)(d) The flow rate of the first gas 40 supplied from the gas supply unit 10 during exposure (first flow rate) is greater than (c) the flow rate of the first gas 40 supplied from the gas supply unit 10 during measurement (second flow rate).

[0032] Furthermore, (d) during exposure, it is advantageous to make the flow rate (first flow rate) of the first gas 40 supplied from the gas supply unit 10 faster than the flow velocity of the second gas 41. Therefore, the control unit 23 controls the supply of gas by the gas supply unit 10 so that the flow velocity of the first gas 40 is greater than the flow velocity of the second gas 41 supplied from the air conditioning unit 5.

[0033] In addition, (d) it is preferable that the flow rate of the first gas 40 supplied from the gas supply unit 10 during exposure (first flow rate) be equal to or greater than the moving speed of the substrate stage 4 as it scans during exposure. Therefore, the control unit 23 controls the supply of gas by the gas supply unit 10 so that the flow velocity of the first gas 40 is greater than the scanning speed of the substrate stage 4. The reason for this is that it is necessary to blow away contaminants 50 during the scanning movement of the substrate stage 4, and this is to avoid any interference with that blowing away process.

[0034] (c) The flow rate of the first gas 40 during measurement is preferably set to be smaller than (d) the flow rate of the first gas 40 during exposure, and to have a flow velocity of approximately the same as that of the second gas 41. A flow velocity of approximately the same as that of the first gas 40 and the second gas 41 means a flow velocity difference that does not cause turbulence due to the difference in flow velocities between the first gas 40 and the second gas 41, but rather creates a flow that is close to laminar flow, and does not necessarily have to be perfect laminar flow. For example, if the flow velocity of the second gas 41 is 1 to 2 m / s, it is preferable to set the flow velocity of the first gas 40 in the region below the measurement unit 7 to be approximately 0 to 3 m / s. If the flow is close to laminar flow, it becomes less likely for air from the surrounding atmosphere to be entrained and mixed, and air fluctuations are small, that is, an atmosphere with stable temperature, pressure and humidity can be obtained. Therefore, high measurement accuracy can be obtained by the measurement unit 7. Furthermore, in the case of a weak flow close to laminar flow, only a stable, weak force is applied to the structure of the measurement unit 7, and the strong forces, shocks, and unexpected vectors caused by turbulence are reduced. This is advantageous for the measurement unit 7 in terms of vibration.

[0035] During periods other than the exposure period and the period during which measurements are taken by the measurement unit 7, i.e., during the sequences (a), (b), and (e), the flow rate should be adjusted within the range between the first flow rate and the second flow rate. Also, if measurement (c) is performed independently, the flow rate setting value by the flow rate adjustment unit 20 during that section should be the second flow rate.

[0036] Next, we will explain the timing at which it is preferable for the flow rate adjustment unit 20 to adjust the first gas 40. When the substrate stage 4 transitions from (c) measurement to (d) exposure, it is preferable that the adjustment by the flow rate adjustment unit 20 is completely completed and the flow rate switches within the movement time of the substrate stage 4. It is preferable that the flow rate is changed smoothly during this switch. That is, the control unit 23 controls the flow rate adjustment unit 20 so that the transition between the first flow rate and the second flow rate is continuous or stepwise, for example. However, the flow rate may be changed abruptly during this switch. A preferred switch is that the flow rate is adjusted to the first flow rate before reaching the exposure start position, and switched to the second flow rate before reaching the measurement start position. However, even if the flow rate switch is delayed, the effect of maintaining measurement accuracy and the effect of preventing contaminants 50 from reaching the optical element 3 remain. Also, if the temperature of the first gas 40 changes due to a large change in the flow rate of the first gas 40, it is advisable to set the temperature adjustment value of the air conditioning unit 26 to change according to the change in flow rate. For example, the temperature of the first gas 40 when it reaches below the projection optical system 2 is adjusted to be constant in both the case of the first flow rate and the case of the second flow rate. If it is difficult to predict temperature changes, a temperature sensor 27 may be placed in the gas supply unit 10, as shown in Figure 5, and the air conditioning unit 26 may be used to control the temperature according to the measurement results from the temperature sensor 27.

[0037] Even when the substrate stage 4 moves from (b) focus adjustment and reference position adjustment to (c) measurement, it is preferable that the adjustment by the flow rate adjustment unit 20 is completed and the flow rate is switched within the movement time of the substrate stage 4.

[0038] <Second Embodiment> Referring to Figure 6, the exposure apparatus 100 according to the second embodiment will be described. In the second embodiment, the same reference numerals are used for components that are the same as those in the first embodiment described above, and their descriptions are omitted. Matters not specifically mentioned in the following description will follow the description of the first embodiment described above.

[0039] In Figure 6, the exposure apparatus 100 further comprises an exhaust unit 70 and an exhaust flow rate adjustment unit 81. The exhaust unit 70 has an exhaust port 71 that exhausts gas from the space between the optical element 3 and the measuring unit 7. In the second embodiment, the flow rate of the first gas 40 is adjusted by the flow rate adjustment unit 20, similar to the first embodiment, and the exhaust flow rate is adjusted accordingly by the exhaust flow rate adjustment unit 81.

[0040] The exhaust section 70 not only discharges pollutants 50 blown away by the first gas 40 from the gas supply section 10, but also functions to rectify the high-speed flow of the first gas 40. For this reason, the exhaust section 70 is positioned downstream of the gas supply section 10, as shown in Figure 6. Furthermore, it is preferable to position the exhaust section 70 between the optical element 3 and the measurement section 7. The reasons for this are as follows:

[0041] The first reason is to reduce the amount of pollutants 50 that reach the measurement unit 70. As shown in Figure 7(a), if the exhaust unit 70 is located between the optical element 3 and the measurement unit 7, the pollutants 50 blown away by the first gas 40 will be partially sucked in through the exhaust port 71, thus reducing the amount that reaches the measurement unit 7.

[0042] The second reason is to improve the anti-fogging performance for the optical element 3. When the substrate stage 4 moves below the measurement unit 7, the flow rate of the first gas 40 is set to the second flow rate by the flow rate adjustment unit 20, which reduces the flow velocity and the force that blows away the contaminants 50. However, as shown in Figure 7(b), because the exhaust unit 70 is positioned, even if there are contaminants 50 remaining on the substrate W, those contaminants 50 are sucked in by the exhaust port 70, so the amount of contaminants 50 that reach the optical element 3 is reduced.

[0043] Thirdly, by drawing in the first gas 40 before it reaches below the measuring unit 7, the flow of the first gas 40 can be more easily slowed down. This makes it easier to reduce the flow rate adjustment range of the first gas 40 compared to the first embodiment.

[0044] Next, a preferred exhaust flow rate adjustment value for the exhaust section 70 will be described. The exhaust flow rate adjustment value is preferably 50% or more of the flow rate adjustment value of the first gas 40, and more preferably greater than or equal to the flow rate adjustment value of the first gas 40. This is to rectify the high-speed flow of the first gas 40 as described above. If the flow rate adjustment value of the first gas 40 becomes large, the flow may become blocked because the space between the optical element 3 and the substrate W is narrow. To reduce this flow blockage, the exhaust flow rate adjustment value may be set to a magnitude related to the flow rate adjustment value of the first gas 40. Furthermore, in order to reduce this flow blockage, when the first gas 40 is adjusted to a first flow rate, it is preferable that the exhaust flow rate adjustment is completed before the adjustment to the first flow rate is completed. However, this is not essential.

[0045] <Third Embodiment> The exposure apparatus 100 according to the third embodiment will be described with reference to Figures 8 and 9. In the third embodiment, the same reference numerals are used for components that are the same as those in the first and second embodiments described above, and their descriptions are omitted. Matters not specifically mentioned in the following description will follow the descriptions of the first and second embodiments described above.

[0046] In the third embodiment, the flow rate adjustment unit 20 includes multiple flow rate adjustment units. Although the exhaust unit 70 and exhaust flow rate adjustment unit 81 shown in the second embodiment are not depicted in Figures 8 and 9, they may be included.

[0047] In the example shown in Figure 8, the flow rate adjustment unit 20 may include a first flow rate adjustment unit 20a and a second flow rate adjustment unit 20b. In one example, the first flow rate adjustment unit 20a sets the gas flow rate to a first flow rate, and the second flow rate adjustment unit 20b sets the gas flow rate to a second flow rate. Each of the first flow rate adjustment unit 20a and the second flow rate adjustment unit 20b can control the gas output ON / OFF (under the control of the control unit 23 described later). Alternatively, the second flow rate adjustment unit 20b may always flow gas at a second flow rate, and the first flow rate adjustment unit 20a may set the gas flow rate such that the total flow rate of gas from the first flow rate adjustment unit 20a and the gas from the second flow rate adjustment unit 20b equals the first flow rate. The first flow rate adjustment unit 20a can then control the gas output ON / OFF (under the control of the control unit 23).

[0048] In the example shown in Figure 9, the flow rate adjustment unit 20 may include a first flow rate adjustment unit 20a, a second flow rate adjustment unit 20b, and a third flow rate adjustment unit 20c. Each of the first flow rate adjustment unit 20a, the second flow rate adjustment unit 20b, and the third flow rate adjustment unit 20c can control the total gas flow rate by controlling the gas output ON / OFF. For example, the second flow rate adjustment unit 20b and the third flow rate adjustment unit 20c each set a gas flow rate such that the sum of the gas flow rates from both is a second flow rate. The first flow rate adjustment unit 20a sets a gas flow rate such that the sum of the gas flow rates from the first flow rate adjustment unit 20a, the second flow rate adjustment unit 20b, and the third flow rate adjustment unit 20c each is a first flow rate. Each of the first flow rate adjustment unit 20a, the second flow rate adjustment unit 20b, and the third flow rate adjustment unit 20c can control the gas output ON / OFF (under the control of the control unit 23). In this way, the adjustment resolution of the gas flow rate can be increased according to the number of flow rate adjustment systems in the flow rate adjustment unit 20, and a variety of gas flow rates can be achieved.

[0049] <Embodiment of an exposure apparatus> Figure 10 shows the overall configuration of the exposure apparatus 100. The exposure apparatus 100 may include an illumination optical system 21, a master plate stage 22, a projection optical system 2, a substrate stage 4, and a control unit 23. The illumination optical system 21 uses light from a light source 24 (e.g., a laser light source) to illuminate the master plate M held by the master plate stage 22. The projection optical system 2 projects a pattern image from the master plate M onto the substrate W held by the substrate stage 4. This transfers the pattern to the resist coated on the substrate W. The substrate stage 4 and the master plate stage 5 move by scanning in response to commands from the control unit 23.

[0050] The air conditioning unit 26 is equipped with piping components for supplying the first gas 40 to the gas supply unit 10 through the flow rate adjustment unit 20, supplying, for example, clean air or nitrogen gas to the gas supply unit 10. The space in which the gas supply unit 10 is located is supplied with the second gas 41 from the air conditioning device 5. The source of the second gas 41 may be the air from the cleanroom, making it difficult to maintain a completely clean state. Furthermore, the space in which the gas supply unit 10 is located contains the drive system and structure of the substrate stage 4, or the components themselves, which use grease, adhesives, resins, rubber, etc., which are prone to generating contaminants, making it difficult to maintain a completely clean state.

[0051] As described in the first to third embodiments, the gas supply unit 10 is positioned in or near the projection optical system 2 and supplies the first gas 40 between the lowest optical element 3 of the projection optical system 2 and the substrate stage 4. The gas supply unit 10 supplies the first gas 40 to protect the optical element 3 from contaminants 50 and contaminated second gas 41 generated from the substrate W while the substrate W is held by the substrate stage 4. This prevents or slows down fogging of the optical element 3.

[0052] During exposure using the projection optical system 2, the control unit 23 controls the flow rate adjustment unit 20 so that the flow rate (first flow rate) of the first gas 40 supplied from the gas supply unit 10 is equal to or greater than the flow rate during other sequences. On the other hand, during measurement using the measurement unit 7, the control unit 23 controls the flow rate adjustment unit 20 so that the flow rate (first flow rate) of the first gas 40 supplied from the gas supply unit 10 is less than the flow rate of the first gas 40 supplied from the gas supply unit 10 during exposure. For example, the control unit 23 controls the flow rate adjustment unit 20 so that the flow velocity of the first gas 40 supplied from the gas supply unit 10 is about the same as the flow velocity of the second gas 41 from the air conditioning unit 5. This makes it possible to maintain high accuracy in the measurement by the measurement unit 7.

[0053] <Embodiment of Article Manufacturing Method> The article manufacturing method according to an embodiment of the present invention is suitable for manufacturing articles such as microdevices, semiconductor devices, and elements having a microstructure. The article manufacturing method of this embodiment includes the steps of forming a latent image pattern on a photosensitive agent coated on a substrate using the above-described exposure apparatus (a step of exposing the substrate) and developing the substrate on which the latent image pattern was formed in the above step. Furthermore, this manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method of this embodiment is advantageous over conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0054] The disclosures herein include at least the following technologies: (Item 1) An exposure apparatus for exposing a substrate, A projection optical system that projects an image of the pattern of the original plate onto the substrate, A supply unit that supplies gas to the space between the projection optical system and the substrate, A measuring unit for measuring the position of the substrate, A control unit controls the supply of gas by the supply unit so that the flow velocity of the gas passing between the measurement unit and the substrate changes, An exposure apparatus characterized by having the following features. (Item 2) The exposure apparatus according to item 1, characterized in that the control unit controls the supply of gas by the supply unit so that the flow velocity of the gas passing between the measurement unit and the substrate changes in accordance with the progress of the exposure sequence. (Item 3) The exposure apparatus according to item 2, characterized in that the control unit controls the supply of gas by the supply unit so that the gas flow velocity between the measurement unit and the substrate is smaller than the flow velocity during the exposure period during the period in which the measurement unit performs measurements. (Item 4) The aforementioned supply unit is A gas supply port for blowing out the gas supplied to the aforementioned space, It includes a flow rate adjustment unit that adjusts the flow rate of gas blown out from the gas supply port, The control unit controls the flow rate adjustment unit to change the flow velocity of the gas passing between the measurement unit and the substrate. An exposure apparatus according to any one of items 1 to 3, characterized by the features described above. (Item 5) The control unit, During the exposure period, the flow rate adjustment unit is controlled so that the flow rate of the gas blown out from the gas supply port becomes the first flow rate. During the period in which the measurement unit performs the measurement, the flow rate adjustment unit controls the flow rate of the gas blown out from the gas supply port to a second flow rate that is smaller than the first flow rate. The exposure apparatus according to item 4, characterized by the features described herein. (Item 6) The aforementioned supply unit is A gas supply port for blowing out the gas supplied to the aforementioned space, It includes a plurality of flow rate adjustment units that adjust the flow rate of gas blown out from the gas supply port, The control unit changes the flow velocity of the gas passing between the measuring unit and the substrate by individually controlling the plurality of flow rate adjustment units. An exposure apparatus according to any one of items 1 to 3, characterized by the above. (Item 7) The control unit, During the exposure period, the plurality of flow rate adjustment units are controlled so that the flow rate of the gas blown out from the gas supply port becomes the first flow rate. During the period in which the measurement unit performs the measurement, the plurality of flow rate adjustment units are controlled so that the flow rate of the gas blown out from the gas supply port becomes a second flow rate which is smaller than the first flow rate. The exposure apparatus according to item 6, characterized by the features described therein. (Item 8) The exposure apparatus according to item 5, further comprising an exhaust unit for discharging gas from the aforementioned space. (Item 9) The aforementioned exhaust section is With respect to the airflow of the gas supplied by the supply unit, an exhaust port is provided at a position downstream of the projection optical system and upstream of the measurement unit to exhaust gas from the space, It includes an exhaust flow rate adjustment unit that adjusts the exhaust flow rate from the exhaust port, The control unit controls the exhaust flow rate adjustment unit according to the gas supply flow rate from the supply unit. The exposure apparatus according to item 8, characterized by the features described above. (Item 10) The exposure apparatus according to item 9, characterized in that the control unit controls the exhaust flow rate adjustment unit so that the exhaust flow rate from the exhaust port is greater than the flow rate of gas blown out from the gas supply port. (Item 11) The exposure apparatus according to item 9 or 10, characterized in that the exhaust flow rate adjustment by the exhaust flow rate adjustment unit is completed before the adjustment to the first flow rate by the flow rate adjustment unit is completed. (Item 12) The exposure apparatus according to item 5, characterized in that the control unit controls the flow rate adjustment unit so that the flow rate of the gas blown out from the gas supply port is within the range between the first flow rate and the second flow rate during periods other than the exposure period and the period during which the measurement unit performs measurements. (Item 13) The exposure apparatus according to item 5, characterized in that the control unit controls the flow rate adjustment unit so that the transition between the first flow rate and the second flow rate is continuous or stepwise. (Item 14) The exposure apparatus according to any one of items 1 to 13, characterized in that the measuring unit is located downstream of the projection optical system with respect to the gas flow supplied by the supply unit. (Item 15) The exposure apparatus according to any one of items 1 to 13, characterized in that the measuring unit is positioned upstream of the projection optical system with respect to the gas flow supplied by the supply unit. (Item 16) The exposure apparatus according to any one of items 1 to 15, characterized in that the control unit controls the supply of gas by the supply unit so that the flow velocity of the gas supplied from the supply unit and passing through the space is greater than the flow velocity of the gas supplied from the air conditioning unit that provides air conditioning for the room in which the exposure apparatus is housed and passing through the space. (Item 17) The stage has a stage that holds and moves the substrate, The exposure apparatus according to any one of items 1 to 16, characterized in that the control unit controls the supply of gas by the supply unit so that the flow velocity of the gas supplied from the supply unit and passing through the space is greater than the scanning speed of the stage. (Item 18) A step of exposing a substrate using an exposure apparatus described in any one of items 1 to 17, The process of developing the exposed substrate, A method for manufacturing an article, characterized by including a developed substrate and manufacturing an article from the developed substrate.

[0055] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0056] 100: Exposure device, 2: Projection optical system, 4: Substrate stage, 7: Measurement unit, 10: Gas supply unit, 11: Gas supply port, 20: Flow rate adjustment unit

Claims

1. An exposure apparatus for exposing a substrate, A projection optical system that projects an image of the pattern of the original plate onto the substrate, A supply unit that supplies gas to the space between the projection optical system and the substrate, A measuring unit for measuring the position of the substrate, A control unit controls the supply of gas by the supply unit so that the flow velocity of the gas passing between the measurement unit and the substrate changes, An exposure apparatus characterized by having the following features.

2. The exposure apparatus according to claim 1, characterized in that the control unit controls the supply of gas by the supply unit so that the flow velocity of the gas passing between the measurement unit and the substrate changes in accordance with the progress of the exposure sequence.

3. The exposure apparatus according to claim 2, characterized in that the control unit controls the supply of gas by the supply unit so that the gas flow velocity between the measurement unit and the substrate is smaller than the flow velocity during the exposure period during the period in which the measurement unit performs measurements.

4. The aforementioned supply unit is A gas supply port for blowing out the gas supplied to the aforementioned space, It includes a flow rate adjustment unit that adjusts the flow rate of gas blown out from the gas supply port, The control unit controls the flow rate adjustment unit to change the flow velocity of the gas passing between the measurement unit and the substrate. The exposure apparatus according to feature 1.

5. The control unit, During the exposure period, the flow rate adjustment unit is controlled so that the flow rate of the gas blown out from the gas supply port becomes the first flow rate. During the period in which the measurement unit performs the measurement, the flow rate adjustment unit controls the flow rate of the gas blown out from the gas supply port to a second flow rate that is smaller than the first flow rate. The exposure apparatus according to feature 4.

6. The aforementioned supply unit is A gas supply port for blowing out the gas supplied to the aforementioned space, It includes a plurality of flow rate adjustment units that adjust the flow rate of gas blown out from the gas supply port, The control unit changes the flow velocity of the gas passing between the measuring unit and the substrate by individually controlling the plurality of flow rate adjustment units. The exposure apparatus according to feature 1.

7. The control unit, During the exposure period, the plurality of flow rate adjustment units are controlled so that the flow rate of the gas blown out from the gas supply port becomes the first flow rate. During the period in which the measurement unit performs the measurement, the plurality of flow rate adjustment units are controlled so that the flow rate of the gas blown out from the gas supply port becomes a second flow rate that is smaller than the first flow rate. The exposure apparatus according to feature 6.

8. The exposure apparatus according to claim 5, further comprising an exhaust unit for discharging gas from the aforementioned space.

9. The aforementioned exhaust section is With respect to the airflow of the gas supplied by the supply unit, an exhaust port is provided at a position downstream of the projection optical system and upstream of the measurement unit to exhaust gas from the space, It includes an exhaust flow rate adjustment unit that adjusts the exhaust flow rate from the exhaust port, The control unit controls the exhaust flow rate adjustment unit according to the gas supply flow rate from the supply unit. The exposure apparatus according to feature 8.

10. The exposure apparatus according to claim 9, characterized in that the control unit controls the exhaust flow rate adjustment unit so that the exhaust flow rate from the exhaust port is greater than the flow rate of gas blown out from the gas supply port.

11. The exposure apparatus according to claim 9, characterized in that the exhaust flow rate adjustment by the exhaust flow rate adjustment unit is completed before the adjustment to the first flow rate by the flow rate adjustment unit is completed.

12. The exposure apparatus according to claim 5, characterized in that the control unit controls the flow rate adjustment unit so that the flow rate of the gas blown out from the gas supply port is within the range between the first flow rate and the second flow rate during periods other than the exposure period and the period during which the measurement unit performs measurements.

13. The exposure apparatus according to claim 5, characterized in that the control unit controls the flow rate adjustment unit so that the transition between the first flow rate and the second flow rate is continuous or stepwise.

14. The exposure apparatus according to claim 1, characterized in that the measuring unit is located downstream of the projection optical system with respect to the gas flow supplied by the supply unit.

15. The exposure apparatus according to claim 1, characterized in that the measuring unit is positioned upstream of the projection optical system with respect to the gas flow supplied by the supply unit.

16. The exposure apparatus according to claim 1, characterized in that the control unit controls the supply of gas by the supply unit so that the flow velocity of the gas supplied from the supply unit and passing through the space is greater than the flow velocity of the gas supplied from the air conditioning unit that provides air conditioning for the room in which the exposure apparatus is housed and passing through the space.

17. The stage has a stage that holds and moves the substrate, The exposure apparatus according to claim 1, characterized in that the control unit controls the supply of gas by the supply unit so that the flow velocity of the gas supplied from the supply unit and passing through the space is greater than the scanning speed of the stage.

18. A step of exposing a substrate using an exposure apparatus according to any one of claims 1 to 17, The process of developing the exposed substrate, A method for manufacturing an article, characterized by including a developed substrate and manufacturing an article from the developed substrate.

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