Illumination device, exposure apparatus, method for manufacturing article, method for determining shutter abnormality, and shutter abnormality determination program

Abstract

To provide an illumination device that can detect abnormality of a shutter even in the case where fine leakage light of a quantization resolution or less in A / D conversion is generated.SOLUTION: An illumination device has: a light source; a shutter which switches an irradiation state and a light shielding state of light from the light source by inserting / removing a light shielding plate to / from an optical path; a sensor which is arranged on the post stage of the shutter, and detects illuminance of light having passed through the shutter; an offset circuit which applies an offset voltage to a first signal output from the sensor in the light shielding state to obtain a second signal; an A / D conversion part which performs A / D conversion to the second signal to obtain a third signal; and a determination part which determines the presence of abnormality in the light-shielding properties of the shutter on the basis of a result of the A / D conversion.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an illumination device, an exposure device, an article manufacturing method, a shutter abnormality determination method, and a shutter abnormality determination program. [Background technology]

[0002] In a manufacturing process (photolithography process) of a semiconductor device or the like, an exposure apparatus is used to expose a substrate to light. The exposure apparatus includes, for example, an illumination device that is provided with a shutter having a light blocking member that blocks light from a light source and can control the amount of exposure of the substrate by driving the shutter to switch between irradiating and not irradiating the substrate with light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-134829 A Summary of the Invention [Problem to be solved by the invention]

[0004] The shutter may reach an abnormal state where the amount of light cannot be controlled correctly due to various factors such as fatigue accumulation due to acceleration and deceleration during operation, and thermal expansion and contraction due to heat input when blocking illumination light, causing an abnormality in the light blocking member. If an abnormality occurs in the shutter, it is necessary to detect the abnormal state, interrupt the exposure process, and display a message to the user urging them to replace the shutter.

[0005] Patent Document 1 discloses a technique for reducing drift in the sensor output and the effects of electrical noise by accumulating and updating the sensor output for each of multiple shutter blades while the shutter is in a light-shielding state, and comparing the accumulated values ​​between the shutter blades. However, the method of Patent Document 1 cannot detect an abnormality in the shutter even if light leakage occurs in an amount of change in output that is less than the quantization resolution in A / D conversion.

[0006] An object of the present invention is to provide an illumination device that can detect a shutter abnormality even when minute leaked light occurs that is less than the quantization resolution in A / D conversion. [Means for solving the problem]

[0007] In order to solve the above problems, the lighting device is characterized by having a light source, a shutter that switches between an irradiation state and a shading state of light from the light source by inserting and removing a light shielding plate into and from an optical path, a sensor arranged downstream of the shutter and detecting the illuminance of light that has passed through the shutter, an offset circuit that applies an offset voltage to a first signal output from the sensor in the shading state to obtain a second signal, an A / D conversion unit that performs A / D conversion on the second signal to obtain a third signal, and a judgment unit that judges whether or not there is an abnormality in the shading property of the shutter based on the result of the A / D conversion. Effect of the Invention

[0008] According to the present invention, it is possible to provide an illumination device that can detect an abnormality in the shutter even when minute leakage light occurs that is less than the quantization resolution in A / D conversion. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a configuration of an exposure apparatus including an illumination device. [Diagram 2] 1 is a conceptual diagram showing the relationship between the shutter position and the integrated exposure amount. [Diagram 3] 1 is a conceptual diagram showing a configuration of a lighting device according to a first embodiment. [Figure 4] 11 is a flowchart of a process for determining an offset addition value in checking for leak light in the lighting device according to the first embodiment. [Diagram 5] 4 is a flowchart of a leak light checking process in the lighting device according to the first embodiment. [Figure 6] 6 is a diagram showing the relationship between the position of the blade and the A / D converted value of the sensor output in the leakage light confirmation process of the lighting device according to the first embodiment. FIG. [Figure 7] 11 is a diagram illustrating a method for checking leak light from a lighting device according to a second embodiment. [Figure 8] 13 is a flowchart of an exposure process including a leak light confirmation process of the illumination device according to the second embodiment. [Figure 9] 13 is a flowchart of an offset addition value calibration process in the lighting device according to the fourth embodiment. [Figure 10] 13 is a flowchart of a leak light checking process in the lighting device according to the fifth embodiment. [Figure 11] 13 is a diagram showing the relationship between the position of the blade and the A / D converted value of the sensor output in the leakage light confirmation process of the lighting device according to the fifth embodiment. FIG. [Figure 12] FIG. 13 is a diagram showing a history of leakage light measurement values ​​in the leakage light confirmation process in the lighting device according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a lighting device according to the present embodiment will be described in detail with reference to the accompanying drawings. Note that the drawings shown below may be drawn at a scale different from the actual scale in order to facilitate understanding of the present embodiment.

[0011] In a stepper type exposure apparatus using an ultraviolet light lamp for exposure, a shutter (exposure shutter, light shielding plate) is used to control the timing and amount of light irradiation. The shutter is, for example, a rotating body (rotating blade) composed of multiple shutter blades having a light shielding portion that shields the light beam and a light transmitting portion that transmits the light beam. In the exposure apparatus, the shutter is driven from the light shielding state to the light irradiation state and stopped, and when a predetermined exposure time has elapsed and a predetermined exposure amount has been reached, the shutter is driven from the light irradiation state to the light shielding state to end the exposure. Another control method is a method in which the shutter is driven from the light shielding state to the light irradiation state and driven without stopping until it is in the light shielding state by another shutter blade. In this case, the desired exposure amount is obtained by controlling the drive speed. When exposure is completed, the drive stage holding the exposure target is driven to the next exposure area. When the drive of the drive stage is completed, the shutter is driven to be in the light irradiation state again and exposure begins. The exposure apparatus performs exposure processing by repeating this series of operations for a predetermined number of shots.

[0012] The shutter may become abnormal due to various factors such as fatigue caused by acceleration and deceleration during operation, and thermal expansion and contraction caused by heat input when blocking the illumination light, leading to an abnormal state in which the amount of exposure cannot be controlled correctly. If an abnormality occurs in the shutter, it is necessary to detect the abnormal state, interrupt the exposure process, and display a message to the user urging them to replace the shutter.

[0013] When the light-blocking function of the shutter deteriorates, an abnormal state (a state in which light leakage occurs) occurs in which a considerable amount of illumination light passes through when the light is blocked. This abnormal state can be determined by obtaining the illuminance by analog / digital conversion (hereinafter referred to as A / D conversion) of the output of the sensor placed after the shutter after the shutter has been driven to the light-blocking state, and checking whether the illuminance is below a specified illuminance level. However, to prevent false detection, the specified illuminance level takes into account the drift of the sensor output, the A / D conversion accuracy, and electrical noise, and there is a risk that minute amounts of leaked light will be overlooked. Therefore, a means of measuring leaked light with high accuracy is required.

[0014] An object of this embodiment is to provide an illumination device that can detect an abnormality in the shutter even when minute leaked light occurs that is less than the quantization resolution in A / D conversion. EXAMPLES

[0015] FIG. 1 is a diagram showing the configuration of an exposure apparatus 100 that uses an illumination apparatus 50.

[0016] The illumination device 50 includes a lamp 1 that emits light including ultraviolet light for exposure, an elliptical mirror 2 that guides the light from the lamp 1 onto a reticle 61, and a rotary shutter 3 that controls the time for illuminating the reticle 61 with the light from the elliptical mirror 2. The shutter 3 has a plurality of blades 3a that block the light beam, and an area 3b that transmits the light beam is formed between the adjacent blades 3a. Between the elliptical mirror 2 and the shutter 3, a second shutter 30 is provided that can be inserted into and removed from the optical path and completely blocks the illumination light. After passing through the shutter 3, a portion of the light is reflected by a half mirror 5 through a lens 4 and is guided to a sensor 8 for measuring the integrated exposure amount. The sensor 8 detects the illuminance of the light that has passed through the shutter 3. The remaining light that has passed through the half mirror 5 is reflected by a folding mirror 60 and irradiated onto a reticle 61 placed on a reticle stage 62. An image of the pattern formed on the reticle 61 is formed on the substrate 64 by a projection optical system 63 configured to have a conjugate relationship between the reticle 61 and a substrate 64 placed on a substrate stage 65 .

[0017] The shutter 3 is driven by a motor 6, and the rotation of the shutter 3 is detected by an encoder 7. A current driver 10 controls the driving of the motor 6. An FVC (Frequency Voltage Converter) 11 converts a pulse train proportional to the speed of the shutter 3 from the encoder 7 into a voltage. An A / D converter (A / D conversion unit) 12 converts an analog voltage (first signal) proportional to the output from the sensor 8 into digital illuminance data.

[0018] The speed servo amplifier 13 generates an output proportional to the difference between the actual speed of the shutter 3 and the secondary speed command value 24 so that the actual speed of the shutter 3 coincides with the secondary speed command value 24. The multiplier 14 creates the secondary speed command value 24 based on the primary speed command value 21 and gain control data 20 from a controller (control unit) 17. The position counter 15 monitors the rotational position of the shutter 3 and outputs shutter position data 22 to the controller 17.

[0019] The integrated exposure counter 16 counts the output from the A / D converter 12 to monitor the time integral of the illuminance of light incident on the sensor 8 after the operation of opening the shutter 3, and outputs integrated exposure data 23 to the controller 17. The controller 17 controls the operation of the entire illumination device 50, and stores relational expressions and parameters of the shutter drive speed and timing with respect to the integrated exposure. The control system shown in Fig. 1 is an example for realizing the present invention, and does not limit the present invention.

[0020] FIG. 2 is a schematic diagram of the drive state (1) of the shutter 3 and the illuminance (2) during exposure, with the vertical axis representing illuminance and the horizontal axis representing time. First, the shutter 3 starts to move from a state (a) in which it completely blocks the light beam, and the shutter 3 rotates. Even when the shutter 3 starts to rotate, it does not immediately become illuminated by the light beam, and the light blocking state continues until the end of the shutter 3 reaches the end of the light beam (just before b). When the end of the shutter 3 moves beyond the end of the light beam, the light beam begins to pass through, and when the end of the shutter 3 reaches the end on the opposite side of the light beam (c), it becomes completely illuminated.

[0021] When light transmission begins, the sensor 8 outputs an analog voltage according to the illuminance of the light. The analog voltage is converted into digital illuminance data via the A / D converter 12. The exposure amount can be measured by integrating this illuminance data. Then, when the desired exposure amount is reached, the shutter 3 starts to be driven to block the light.

[0022] The drive for blocking light starts the drive of the shutter 3 from a state where the light beam is completely transmitted, and the shutter 3 rotates. When the end of the light beam reaches the end of the shutter 3, the light beam gradually begins to be blocked (e), and when it reaches the end on the opposite side of the light beam (f), the light beam is completely blocked. The exposure amount is accumulated until the complete light blocking state is reached, and the final accumulated exposure amount is determined. In other words, the exposure amount that is set controls the length of time from when the shutter 3 reaches a position where the light beam is completely irradiated until it starts to be driven to the light blocking state.

[0023] Fig. 3 shows an extracted block diagram relating to A / D converter 12 of embodiment 1 of lighting device 50. As shown in Fig. 3, an analog signal based on the illuminance of light output from sensor 8 is input to A / D converter 12, and an A / D conversion value 27 output from A / D converter 12 is also input to controller 17 in parallel with integrated exposure amount counter 16. Controller 17 derives offset value (offset voltage) 26 based on the A / D conversion value output from A / D converter 12, and outputs it to offset adder (offset circuit) 25. Offset adder 25 adds offset value 26 to the input to A / D converter 12 to obtain a second signal.

[0024] Here, a flowchart of the process of determining the offset addition value will be described with reference to the flowchart of Fig. 4. At least one step in the flowchart of Fig. 4 can be executed by the controller 17. In step S101, the controller 17 turns on the power of the lamp 1, which is a light source. In step S102, the controller 17 drives the shutter 3 so as to block the light from the lamp 1. In step S103, the controller 17 sets an initial value of the offset value to be given to the A / D converter 12 in response to requests such as stable operation of the electric circuit. In step S104, in this state (a state in which no light is incident on the sensor 8), the controller 17 reads out an A / D conversion value that is an output from the A / D converter 12 based on the output from the sensor 8.

[0025] In step S105, if the A / D converted value is 0, the process proceeds to step S106, and if the A / D converted value is not 0, the process proceeds to step S107. In step S106, the controller 17 changes the offset value to be output to the offset adder 25 by a small amount to the positive side, and the process returns to step S104. Step S107 is a state in which the A / D conversion value has changed to equal to or greater than 1. Here, the controller 17 changes the offset value to be output to the offset adder 25 by a small amount to the negative side.

[0026] In step S 108 , the controller 17 reads out an A / D converted value which is an output from the A / D converter 12 based on the output from the sensor 8 . In step S109, if the A / D conversion value becomes 0 (if the output from sensor 8 becomes an applied voltage that is a predetermined amount smaller than the voltage at which the A / D conversion value changes from 0 to 1), proceed to step S110, and if the A / D conversion value is 1 or greater, return to step S107. In step S110, the controller 17 determines the offset value 26 as the offset addition value. In this manner, the offset addition value used in the leak light confirmation process is determined.

[0027] Next, a flowchart of the leakage light checking process will be described with reference to Fig. 5. In the flowchart of Fig. 5, at least one step can be executed by the controller 17. In step S201, the controller 17 turns on the power of the lamp 1, which is a light source. In step S202, the controller 17 drives the shutter 3 so as to block the light from the lamp 1. In step S203, the controller 17 sets the offset addition value as the offset value 26. In step S 204 , the controller 17 reads out an A / D converted value which is an output from the A / D converter 12 based on the output from the sensor 8 . In step S205, if the A / D converted value is 0, the process proceeds to step S206, and if not, the process proceeds to step S207. In step S206, the controller (determination unit) 17 determines that there is no leak light for the blade of the shutter 3 for which leak light has been confirmed, and ends the process. In step S207, the controller 17 determines that there is light leakage for that blade of the shutter 3 for which light leakage has been confirmed, and ends the process.

[0028] With reference to Fig. 6, let us consider the relationship between the rotational position (1) of the shutter 3 and the measured illuminance (A / D converted value) (2), (3) when an abnormality such as a hole occurs in blade C of the shutter 3 composed of three blades A, B, and C. Fig. 6(2) shows the case where the process of adding the offset addition value described in Fig. 5 as the offset value 26 is not performed, and Fig. 6(3) shows the case where the process of adding the offset addition value described in Fig. 5 as the offset value 26 is performed.

[0029] When checking for light leakage after each blade has been driven to its light-shielding position, if the level (illuminance) of the leakage light from blade C is equal to or lower than the quantization resolution, and offset value 26 is not added by offset adder 25, A / D conversion value C1 will remain 0 and no abnormality can be detected. In contrast, by adding the offset addition value to the leakage light level as offset value 26 (FIG. 6(3)), A / D conversion value C2 will become 1 only for blade C with an abnormality, making it possible to detect a light leakage abnormality.

[0030] In the first embodiment, the presence or absence of light leakage is determined based on the A / D converted value changing from 0 to 1, but the present invention is not limited to this. The presence or absence of light leakage is determined based on whether the value after A / D conversion, which is the minimum change amount that can be recognized by the quantization resolution of the A / D converter 12, has changed by "1" from a reference value ("0" in the first embodiment). This is the same for the embodiments described below. EXAMPLES

[0031] An illumination device according to a second embodiment will be described with reference to Figs. 7 and 8. Differences from the first embodiment will be described, and descriptions of the same configurations as the first embodiment will be omitted. If normal exposure control is performed with the offset addition value added as offset value 26 to the output of sensor 8, the value read by sensor 8 is not evaluated directly but the value after the addition operation is evaluated, which leads to a decrease in accuracy in exposure control. Therefore, in the lighting device of embodiment 2, controller 17 outputs the offset addition value to offset adder 25 as offset value 26 only when leak light is confirmed, and does not output the offset addition value to offset adder 25 at the timing of normal exposure processing.

[0032] First, a flowchart of an exposure process in an exposure apparatus including an illumination apparatus 50 according to the second embodiment will be described with reference to Fig. 7. At least one step in the flowchart of Fig. 7 can be executed by the controller 17. In step S301, the controller 17 drives the shutter 3 to the light transmitting position. In step S302, the controller 17 powers on the lamp 1. In step S303, the controller 17 drives the shutter 3 to the light blocking position. After step S303 is executed, the processes of steps S304 and S309 are started in parallel. In step S309, reticle stage 62 and substrate stage 65 are driven to align reticle 61 with substrate 64. After step S309 is executed, the process waits for the completion of step S307 of the other parallel process, and then proceeds to step S310. In step S304, the offset addition value is added to the output from the sensor 8 as the offset value 26.

[0033] In step S305, the controller 17 reads out an A / D converted value for the value obtained after adding the output from the sensor 8 to the offset addition value. In step S306, if the A / D converted value in step S305 is greater than 0, the process proceeds to step S308, and if it is 0, the process proceeds to step S307. In step S308, the controller 17 determines that there is light leakage for that blade of the shutter 3 for which light leakage has been confirmed, and ends the process.

[0034] In step S307, the controller 17 determines that there is no leakage light for the blade of the shutter 3 for which leakage light has been confirmed, and returns the offset value 26 to the initial value in order to terminate the leakage light confirmation process and return to normal exposure processing, and proceeds to step S310. Here, returning the offset value to the initial value does not correspond to an offset addition value set for the purpose of checking for leakage light, but corresponds to returning to an offset value, if any, added by the offset adder 25 before checking for leakage light. An example of such an offset value is one that is set for stable operation of the control circuit and does not cause output to become unstable due to minute noise generated by various causes such as temperature, electromagnetic interference, and fluctuations in power supply voltage.

[0035] In step S310, the controller 17 drives the shutter 3 to the light transmitting position. In step S311, the controller 17 integrates the illuminance of the light detected by the sensor 8 and exposes the substrate until a desired exposure amount is reached. In step S312, the controller 17 drives the shutter 3 to the light blocking position. In step S313, if there is a next exposure process, the process returns to steps S309 and S304, and if there is no next exposure process, the process ends.

[0036] The flow of the process of checking leakage light from the shutter 3 in an exposure apparatus including an illumination device will be described with reference to Fig. 8. In Fig. 8, (1) indicates the rotational position of the shutter 3, and (2) indicates the illuminance (A / D converted value) detected by the sensor 8. At time t0 when blade A of shutter 3 is in the light blocking position, controller 17 outputs the offset addition value to offset adder 25 as offset value 26 to check for light leakage. Since blade A has no abnormalities such as cracks, maintains its light blocking properties, and there is no light leakage, the A / D converted value (A3) obtained by A / D converting the signal to which the offset addition value is added by offset adder 25 to the output of sensor 8 remains 0. At time t1 after the predetermined period of light leakage check has ended, controller 17 stops outputting the offset addition value to offset adder 25 as offset value 26.

[0037] In exposure apparatus 100, while in the light-shielded state, reticle stage 62 and / or substrate stage 65 move to align the position of reticle 61 with the position of substrate 64 for the next exposure processing step. After the position of reticle 61 and the position of substrate 64 are aligned for the next exposure processing step, driving of shutter 3 starts at time t2. Driving of shutter 3 stops at time t3 when irradiation state between blades A and B is reached, and exposure to substrate 64 is continued until a predetermined amount of exposure is completed.

[0038] Driving of the shutter 3 starts at time t4, and stops at time t5 when the light is blocked by the blades B. Thereafter, in the exposure apparatus, the reticle stage 62 and / or the substrate stage 65 start to move so as to align the position of the reticle 61 with the position of the substrate 64 for the next exposure processing step.

[0039] Here, at time t6, controller 17 outputs the offset addition value to offset adder 25 as offset value 26 to check for light leakage. For the predetermined time (from time t6 to time t7), blade B has no abnormalities such as cracks, so the light blocking properties are maintained and there is no light leakage, and the A / D converted value (B3) obtained by A / D converting the signal to which the offset addition value is added by offset adder 25 to the output of sensor 8 remains 0. At time t7 after the predetermined time of checking for light leakage has been completed, controller 17 stops outputting the offset addition value to offset adder 25 as offset value 26.

[0040] Thereafter, a process similar to that from time t1 to time t5 is carried out from time t7 to time t11, and at time t11, the shutter 3 reaches a position where the blade C blocks light. At time t12, the controller 17 outputs an offset addition value to the offset adder 25 as an offset value 26 in order to check for leaking light. Because the blade C has a reduced light blocking ability due to a crack or the like, causing light leakage, the A / D conversion value (C3) obtained by A / D converting the signal to which the offset addition value is added by the offset adder 25 to the output of the sensor 8 becomes 1. This causes the controller 17 to determine that there is an abnormality in the blade C. At time t13, after the predetermined period of checking for leaking light has ended, the controller 17 stops outputting the offset addition value to the offset adder 25 as the offset value 26. In this way, in the lighting device of this embodiment, the offset addition value is added to the detection signal of the sensor 8 only when a leakage light anomaly is detected, so that highly accurate leakage light anomaly detection can be achieved without affecting the control accuracy of the light irradiation amount (exposure amount). EXAMPLES

[0041] A lighting device according to Example 3 will be described. In Example 3, a method of determining an offset addition value differs from Example 1. Hereinafter, a description of the same configuration as Example 1 will be omitted, and a method of determining an offset addition value in a lighting device 50 according to Example 3, which differs from the lighting device of Example 1, will be described.

[0042] Since the output of sensor 8 generally contains noise, when the output of A / D converter 12 is near the boundary between 0 and 1, the output of A / D converter 12 may switch between 0 and 1 over time, resulting in an indefinite value. If the instantaneous A / D converted value when light leakage is confirmed in a normal blade is used for judgment, there will be no difference from an abnormal state, and it may not be possible to achieve highly accurate light leakage detection.

[0043] Therefore, when determining the offset addition value, the A / D conversion result is read out multiple times, and the offset value when the average value becomes smaller than a predetermined specified value (first threshold) is set as the offset addition value. Furthermore, when checking for light leakage, instead of determining whether it is normal or abnormal based on a single A / D conversion readout value, the A / D conversion value is read out multiple times, and if the average value is equal to or greater than a specified value (second threshold), it is determined that there is a light leakage abnormality, thereby making it possible to prevent erroneous determinations. EXAMPLES

[0044] Over the long term, the output level of the sensor 8 may drift. If the sensor value drifts, this may affect the A / D conversion results, making it difficult to measure leakage light correctly. For this reason, the offset addition value must be calibrated periodically. Calibration of the offset addition value must be performed in a state where light entering the shutter 3 is completely blocked. For this reason, the second shutter 30 provided before the shutter 3 as shown in FIG. 1 is closed to achieve a state where light entering the shutter 3 is completely blocked, and the offset addition value is calibrated.

[0045] The calibration of the offset addition value can be performed without reducing the productivity of the apparatus by performing the calibration during non-illumination in parallel with the timing during replacement of the substrate 64, rather than during the exposure process in the exposure sequence. A flowchart of the calibration process of the offset addition value is shown in FIG. 9. At least one step in the flowchart of FIG. 9 can be executed by the controller 17.

[0046] First, the calibration process of the offset addition value is started at a timing when the exposure process is not being performed. First, in step S401, the controller 17 confirms that the shutter 3 is in a light blocking state. Next, in step S402, the controller 17 puts the second shutter 30 into a light blocking state. In step S403, the controller 17 sets the offset value 26 to an initial value, and the process proceeds to step S404. In step S404, the controller 17 checks for leakage light. The leakage light check may be performed by reading out the A / D converted values ​​multiple times and calculating the average value, as described in the third embodiment.

[0047] In step S405, the controller 17 compares the average value of the A / D converted values ​​obtained in step S404 with a predetermined specified value. If the obtained average value is smaller than the specified value, the process proceeds to step S406. If the obtained average value is equal to or larger than the specified value, the process proceeds to step S407. In step S406, the controller 17 increases the offset value 26, and the process returns to step S404. In step S407, the controller 17 decreases the offset value 26. In step S408, the controller 17 checks for leaking light. The leaking light check may be performed by reading out the A / D converted values ​​multiple times and calculating the average value, as described in the third embodiment.

[0048] In step S409, the controller 17 compares the average value of the A / D conversion values ​​obtained in step S408 with a predetermined specified value. If the obtained average value is equal to or less than the specified value, the process proceeds to step S410. If the obtained average value is greater than the specified value, the process returns to step S407. In step S410, the controller 17 determines the offset value 26 as the new offset addition value. In step S411, the controller 17 drives the second shutter 30 to the irradiating state, and ends the offset calibration process.

[0049] Here, the specified value used in the determination in step S405 and step S409 is set as a value greater than 0 and less than 1 with respect to the average value of the acquired multiple A / D converted values ​​when the A / D converted value in a state without leaking light is 0. Also, the specified values ​​used in the determination in step S405 and step S409 may be the same or different. The condition for performing calibration has been exemplified as being such that the second shutter 30 preceding the shutter 3 is closed to completely block light entering the shutter 3, but the present invention is not limited to this, and calibration may also be performed with the lamp 1, which is the light source, turned off. EXAMPLES

[0050] In the lighting devices of the previous embodiments, the offset value 26 to be added to the sensor 8 when leak light is checked is determined in advance as an offset addition value, but in this embodiment, the offset value 26 is changed when leak light is checked. A specific method of checking for leak light in the lighting device of this embodiment will be described with reference to Fig. 10. At least one step in the flowchart of Fig. 10 can be executed by the controller 17.

[0051] In this embodiment, checking for leak light in the illumination device is started after the exposure process is completed and the shutter 3 has been driven to the light blocking state, similarly to the previous embodiments. In step S501, the controller 17 drives the shutter 3 to a light blocking state. In step S502, the controller 17 sets the offset value 26 to a predetermined initial value. In step S503, the controller 17 performs leakage light measurement. In step S504, controller 17 determines whether the A / D conversion value is smaller than 1. If the A / D conversion value is smaller than 1, the process proceeds to step S505, and if the A / D conversion value is 1 or greater, the process proceeds to step S506 with offset value 26 at that time as the first voltage. That is, if the A / D conversion value (digital value that is the third signal) is 1 or has changed from 0 to 1, the process proceeds to S506.

[0052] In step S505, the controller 17 increases the offset value 26, and the process returns to step S503. In step S506, the controller 17 compares the first voltage with a predetermined specified value (third threshold value). If the first voltage is smaller than the specified value, the process proceeds to step S508, and if the first voltage is equal to or greater than the specified value, the process proceeds to step S507. In step S508, the controller 17 determines that there is a light leakage abnormality, and ends the light leakage confirmation process. In step S507, the controller 17 determines that there is no light leakage abnormality, resets the offset value 26 to its initial value, and ends the light leakage confirmation process.

[0053] The flow of the process for checking leakage light from the shutter 3 in an exposure apparatus including an illumination apparatus of this embodiment will be described with reference to Fig. 11. In Fig. 11, (1) indicates the rotational position of the shutter 3, and (2) indicates the illuminance (A / D converted value) detected by the sensor 8. In Fig. 11(2), the vertical axis indicates the output of the sensor 8 corresponding to the illuminance, and the numbers 0, 1, and 2 on the vertical axis indicate the digital values ​​after the output of the sensor 8 is A / D converted by the A / D converter 12.

[0054] This shows an example in which, of the three blades, blade C has an abnormality in the form of a hole. In normal blades A and B which are free of cracks or the like, the offset values ​​26 for the addition process required for the A / D conversion value to become 1 are A4 and B4, respectively. In contrast, in blade C which has an abnormality in the form of a hole, the first voltage for the addition process required for the A / D conversion value to become 1 is C4. It can be seen that the first voltage C4 in blade C is smaller than the first voltages A4 and B4 in normal blades A and B.

[0055] The specified value in step S506 in Fig. 10 is experimentally determined and set in advance in consideration of various conditions. For example, the specified value in step S506 is set to a value smaller than A4 and B4 of the first voltages in normal blades A and B shown in Fig. 11 and larger than C4 of the first voltage in blade C where a hole abnormality has occurred. Therefore, if the first voltage obtained by the process of FIG. 10 is smaller than the preset value in step S506, it can be determined that an abnormality has occurred in the blade, making it possible to detect an abnormality in leakage light with high accuracy. EXAMPLES

[0056] Since the output value of the sensor 8 is determined by the size of the hole in the blade of the shutter 3, the leakage light tends to increase over time due to damage to the blade. In the illumination device of this embodiment, the offset value 26 (first voltage) obtained in the leakage light confirmation process in the fifth embodiment is used to aim at leakage light confirmation that detects leakage light abnormalities in the shutter blades before they occur.

[0057] In this embodiment, the change over time (history) of the first voltage for each shutter blade obtained in the light leakage confirmation process shown in the fifth embodiment is monitored, and trend management is performed, thereby making it possible to detect light leakage anomalies in the shutter blades before they occur.

[0058] As shown in Fig. 12, the controller 17 performs a leakage light confirmation process for each exposure process to measure the first voltage, stores the obtained first voltage for each shutter blade, and acquires a time-varying characteristic amount of the first voltage for each shutter blade. If the time-varying characteristic amount is greater than a predetermined threshold, it is determined that the leakage light anomaly is progressing in a worsening direction, and outputs the presence of an anomaly. In this case, even if it is determined that there is no leakage light anomaly by comparing the first voltage obtained in the fifth embodiment with the specified value (third threshold), by trend management of the time-varying change, it is possible to recognize that there is a tendency for leakage light anomaly, and to prevent losses in the exposure process, for example.

[0059] Here, for example, in the leakage light confirmation process performed for each exposure process of the exposure device, the first voltage may be compared with the first voltage in the leakage light confirmation process performed immediately before, and the amount of change may be used as a time-varying characteristic value. The presence or absence of a tendency of leakage light anomaly may be determined by comparing this time-varying characteristic value with a predetermined threshold value. Alternatively, the presence or absence of a tendency of leakage light anomaly may be determined by comparing the amount of change in the first voltage in the leakage light confirmation process obtained at regular intervals with a predetermined threshold value as a time-varying characteristic value. Alternatively, the presence or absence of a tendency of leakage light anomaly may be determined based on the time-varying average value of the first voltage obtained in multiple adjacent (consecutive) leakage light confirmation processes.

[0060] According to the light leakage confirmation processing method for the lighting device of this embodiment, it is possible to detect an escalating tendency toward a light leakage anomaly at an early stage before a light leakage anomaly is actually detected, and to detect a light leakage anomaly with even higher accuracy.

[0061] [Production method] The method for manufacturing an article according to this embodiment is suitable for manufacturing articles such as microdevices, such as semiconductor devices, and elements having a microstructure. The method for manufacturing an article according to this embodiment includes a step of forming a latent image pattern in a photosensitive agent applied to a substrate using exposure apparatus 100 including illumination apparatus 50 described above (a step of exposing the substrate to light). The method for manufacturing an article according to the present embodiment also includes a step of developing the substrate on which the latent image pattern is formed. Furthermore, the method for manufacturing an article according to this embodiment includes other well-known manufacturing steps (oxidation, film formation, deposition, doping, planarization, etching, photosensitive agent stripping, dicing, bonding, packaging, etc.) performed on the developed substrate.

[0062] The method for manufacturing an article according to this embodiment is advantageous in at least one of the performance, quality, productivity, and production costs of the article, as compared to conventional methods.

[0063] [Other Examples] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-mentioned embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0064] The disclosure of this embodiment includes the following configuration, method, and program. (Configuration 1) A light source; a shutter that switches between an illumination state and a light blocking state of light from the light source by inserting and removing a light blocking plate into and from an optical path; a sensor disposed downstream of the shutter and configured to detect the illuminance of light passing through the shutter; an offset circuit that applies an offset voltage to a first signal output from the sensor in the light-shielded state to obtain a second signal; an A / D conversion unit that performs A / D conversion on the second signal to obtain a third signal; and a determination unit that determines whether or not there is an abnormality in the light blocking property of the shutter based on a result of the A / D conversion. (Configuration 2) 2. The lighting device according to claim 1, further comprising a control unit that controls the offset voltage based on the result of the A / D conversion. (Configuration 3) 3. The lighting device according to claim 1, wherein the determination unit determines whether or not there is an abnormality in the light blocking property of the shutter based on a change of 1 in the value of the third signal in the light blocking state. (Configuration 4) 4. The illumination device according to configuration 3, wherein the determination unit determines whether or not there is an abnormality in the light blocking property of the shutter based on the third signal changing from 0 to 1 in the light blocking state. (Configuration 5) 5. The illumination device according to any one of configurations 1 to 4, wherein the offset circuit applies the offset voltage only when the shutter is in the light blocking state. (Configuration 6) The lighting device described in configuration 2, characterized in that, in the light-blocking state where there is no leakage light, the control unit determines the offset voltage based on the fact that an average value of the third signal obtained by multiple A / D conversions is smaller than a first threshold value. (Configuration 7) The lighting device according to any one of configurations 1 to 6, wherein the determination unit performs the determination based on a comparison, in the light-blocking state, between an average value of the third signal obtained by multiple A / D conversions and a second threshold value. (Configuration 8) 3. The lighting device according to claim 2, wherein the control unit calibrates the offset voltage when lighting is not performed. (Configuration 9) a second shutter that is insertable into and removable from the optical path and switches between an illumination state and a light blocking state of the light from the light source; 9. The illumination device according to configuration 8, wherein the calibration is performed while the second shutter is in the light blocking state. (Configuration 10) 9. The illumination device according to claim 8, wherein the calibration is performed while the light source is turned off. (Configuration 11) The lighting device described in configuration 2, wherein the control unit gradually increases the offset voltage in the light-blocking state until the third signal changes, and determines that there is an abnormality in the light-blocking property of the shutter if the offset voltage at that time, which is a first voltage, is smaller than a third threshold value. (Configuration 12) the control unit, in the light-blocking state, gradually increases the offset voltage until the third signal changes, sets the offset voltage at that time as a first voltage, and stores a history of the first voltage; 12. The illumination device according to configuration 11, wherein the determination unit determines whether or not there is an abnormality in the light blocking ability of the shutter based on the history. (Configuration 13) 13. The illumination device according to configuration 11 or 12, wherein the determination unit determines an abnormality in the light blocking ability of the shutter based on an amount of change in the first voltage over a series of times. (Configuration 14) 14. The lighting device according to any one of configurations 1 to 13, wherein the shutter is configured by a rotating blade having a plurality of blades. (Configuration 15) An exposure apparatus that projects an image of a reticle pattern onto a substrate and exposes the substrate, comprising: An exposure apparatus comprising an illumination device according to any one of configurations 1 to 14. (Method 1) exposing the substrate using the exposure apparatus according to configuration 15; developing the exposed substrate; producing an article from the developed substrate; A method for producing an article, comprising: (Method 2) A method for determining an abnormality in a shutter in an illumination device including a light source, a shutter that switches between an irradiation state and a blocking state of light from the light source by inserting and removing a light blocking plate into and from an optical path, and a sensor that is disposed downstream of the shutter and detects light that has passed through the shutter, comprising: applying an offset voltage to a first signal output from the sensor in the light-blocking state to obtain a second signal; performing A / D conversion on the second signal to obtain a third signal; and determining whether or not there is an abnormality in the light blocking property of the shutter based on a result of the A / D conversion. (Method 3) The shutter abnormality determination method according to Method 2, further comprising a step of controlling the offset voltage based on the result of the A / D conversion. (Method 3) The shutter abnormality determination method according to Method 2 or 3, wherein the determining step includes a step of determining whether or not there is an abnormality in the light blocking property of the shutter based on a change in the value of the third signal by 1. (Method 4) The shutter abnormality determination method according to Method 3, wherein the determining step includes a step of determining whether or not there is an abnormality in the light blocking property of the shutter based on a change of the third signal from 0 to 1. (program) A shutter abnormality determination program that, when executed by a processor, causes the processor to execute each step of any one of methods 2 to 4. [Explanation of symbols]

[0065] 1. UV lamp for exposure (light source) 3 Shutter 8 Light sensor 12 A / D converter (A / D conversion section) 16 Accumulated exposure measurement counter 17 Controller (control unit, judgment unit)

Claims

1. A light source; a shutter that switches between an illumination state and a light blocking state of light from the light source by inserting and removing a light blocking plate into and from an optical path; a sensor disposed downstream of the shutter and configured to detect the illuminance of light passing through the shutter; an offset circuit that applies an offset voltage to a first signal output from the sensor in the light-shielded state to obtain a second signal; an A / D conversion unit that performs A / D conversion on the second signal to obtain a third signal; and a determination unit that determines whether or not there is an abnormality in the light blocking property of the shutter based on a result of the A / D conversion.

2. The lighting device according to claim 1 , further comprising a control unit that controls the offset voltage based on the result of the A / D conversion.

3. 2 . The illumination device according to claim 1 , wherein the determination unit determines whether or not there is an abnormality in the light blocking property of the shutter based on a change of 1 in the value of the third signal in the light blocking state.

4. 4. The illumination device according to claim 3, wherein the determination unit determines whether or not there is an abnormality in the light blocking property of the shutter based on a change of the third signal from 0 to 1 in the light blocking state.

5. 2. The illumination device according to claim 1, wherein the offset circuit applies the offset voltage only when the shutter is in the light blocking state.

6. The lighting device according to claim 2 , wherein the control unit determines the offset voltage based on the fact that, in the light-blocking state in which there is no leakage light, an average value of the third signal obtained by multiple A / D conversions is smaller than a first threshold value.

7. The lighting device according to claim 1 , wherein the determination unit performs the determination in the light-blocking state based on a comparison between an average value of the third signal obtained by performing the A / D conversion a plurality of times and a second threshold value.

8. The lighting device according to claim 2 , wherein the control unit calibrates the offset voltage when no illumination is present.

9. a second shutter that is insertable into and removable from the optical path and switches between an illumination state and a light blocking state of the light from the light source; 9. The illumination device according to claim 8, wherein the calibration is performed while the second shutter is in the light blocking state.

10. 9. The lighting device according to claim 8, wherein the calibration is performed while the light source is turned off.

11. 3. The lighting device according to claim 2, wherein the control unit gradually increases the offset voltage in the light-blocking state until the third signal changes, and determines that there is an abnormality in the light-blocking property of the shutter if the offset voltage, which is a first voltage at that time, is smaller than a third threshold value.

12. the control unit, in the light-blocking state, gradually increases the offset voltage until the third signal changes, sets the offset voltage at that time as a first voltage, and stores a history of the first voltage; The illumination device according to claim 11 , wherein the determination unit determines whether or not there is an abnormality in the light blocking ability of the shutter based on the history.

13. The illumination device according to claim 11 , wherein the determination unit determines whether or not there is an abnormality in the light blocking ability of the shutter based on an amount of continuous change in the first voltage.

14. 2. The lighting device according to claim 1, wherein the shutter is constituted by a rotating blade having a plurality of blades.

15. An exposure apparatus that projects an image of a reticle pattern onto a substrate and exposes the substrate, comprising: An exposure apparatus comprising the illumination device according to claim 1 .

16. exposing the substrate using the exposure apparatus according to claim 15; developing the exposed substrate; producing an article from the developed substrate; A method for producing an article, comprising:

17. A method for determining an abnormality in a shutter in an illumination device including a light source, a shutter that switches between an irradiation state and a blocking state of light from the light source by inserting and removing a light blocking plate into and from an optical path, and a sensor that is disposed downstream of the shutter and detects light that has passed through the shutter, comprising: applying an offset voltage to a first signal output from the sensor in the light-blocking state to obtain a second signal; performing A / D conversion on the second signal to obtain a third signal; and determining whether or not there is an abnormality in the light blocking property of the shutter based on a result of the A / D conversion.

18. 18. The shutter abnormality determination method according to claim 17, further comprising the step of controlling the offset voltage based on the result of the A / D conversion.

19. 18. The shutter abnormality determination method according to claim 17, wherein the determining step includes a step of determining whether or not there is an abnormality in the light blocking property of the shutter based on a change of the value of the third signal by 1.

20. 20. The shutter abnormality determination method according to claim 19, wherein the determining step includes a step of determining whether or not there is an abnormality in the light blocking property of the shutter based on a change of the third signal from 0 to 1.

21. A shutter abnormality determination program which, when executed by a processor, causes the processor to execute each step of the method according to any one of claims 17 to 20.

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