JP2012015332A - Measuring optical member, mask, exposure device, exposure method, and manufacturing method of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring optical member capable of measuring optical characteristics of a projection optical system in use, a mask, an exposure device, an exposure method, and a method of manufacturing a device.SOLUTION: A measuring optical member 23 comprises a plurality of measuring pattern units 43A, 43B, and 43C having a pattern forming area 44 in which a measuring pattern 46 is formed and non-pattern forming area 45a, 45b, and 45c disposed at positions different from the pattern forming area 44. The non-pattern forming areas 45a, 45b, and 45c are formed under different forming conditions for each of the measuring pattern units 43A, 43B, and 43C.

Description

  The present invention relates to a measurement optical member on which a measurement pattern is formed, and a mask on which a predetermined pattern for projecting an image on a substrate and a measurement pattern are formed. The present invention also relates to an exposure apparatus that performs various measurements using a radiation beam that passes through at least one of a measurement optical member and a mask, an exposure method, and a device manufacturing method that uses the exposure apparatus.

  In general, in an exposure apparatus for manufacturing a microdevice such as a semiconductor integrated circuit, a mask such as a reticle on which a predetermined pattern is formed is illuminated with exposure light, and the exposure light through the mask is applied with a photosensitive material. By irradiating a substrate such as a wafer, a pattern is formed on the substrate. In such an exposure apparatus, in order to reliably form a pattern in each shot area of the substrate, it is important to adjust the optical characteristics of the projection optical system that guides the exposure light through the mask to the substrate to an appropriate state.

  For this reason, a measurement optical member (also referred to as RFM (reticle fiducial mark)) is provided in a mask holding device that holds a mask in an exposure apparatus. In the measurement optical member, a measurement pattern unit having a measurement pattern used for various measurements such as aerial image measurement and baseline check is formed. The shape of the measurement pattern unit is a shape corresponding to the shape of the illumination area formed on the mask (or measurement optical member) by the illumination optical system (see Patent Document 1).

  As an example, in the case of aerial image measurement, the measurement pattern unit of the measurement optical member is disposed in the optical path of the exposure light, and the exposure light via the measurement pattern unit is incident on the projection optical system. Then, the aerial image of the measurement pattern formed by the exposure light incident on the projection optical system is observed, and the optical characteristics of the projection optical system are calculated based on the observation result. As a result, based on the calculated optical characteristics of the projection optical system, the position and shape of the optical member of the projection optical system are adjusted as necessary.

US Patent Application Publication No. 2002 / 0041377A1

  By the way, the reticle used at the time of forming the pattern on the substrate is formed such that the emission rate, which is the ratio of the exposure light emission amount to the projection optical system side with respect to the exposure light incident amount on the reticle, is about 50%. Has been. On the other hand, the injection rate of the measurement pattern unit of the measurement optical member is largely different from the injection rate of the reticle, and is set to approximately 0 (zero)%. That is, the pattern non-formation region where the measurement pattern is not formed in the measurement pattern unit is formed so that the incident exposure light is hardly emitted to the projection optical system side.

  Therefore, when performing measurement using the measurement optical member between the exposure process for one shot area of the substrate and the exposure process for the next shot area, the amount of exposure light incident on the projection optical system is This is greatly reduced compared to the exposure processing for the area. Then, since the optical member of the projection optical system is cooled by a cooling mechanism or the like, the temperature rapidly decreases. As a result, at the time of measurement, the balance between the heat generation amount and the heat dissipation amount in the projection optical system is lost, and the optical member may be displaced or the shape of the optical member may be changed. That is, there is a possibility that the optical characteristics of the projection optical system differ between the shot area exposure processing and the measurement.

  In particular, in an EUV exposure apparatus that uses EUV (Extreme Ultraviolet) light as exposure light, a change in the amount of heat absorbed by the projection optical system during exposure processing to a shot region of the substrate and during measurement using a measurement pattern unit. Becomes prominent.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a measurement optical member, a mask, an exposure apparatus, an exposure method, and a device manufacturing method capable of measuring the optical characteristics of a projection optical system. Is to provide.

  The optical member for measurement according to the first embodiment includes a pattern formation region (44) where the measurement pattern (46) is formed and a pattern non-formation region (where the pattern formation region (44) is located). 45, 45a, 45b, 45c) having a plurality of measurement pattern units (43A, 43B, 43C), and the pattern non-formation regions (45, 45a, 45b, 45c) include the measurement pattern units (43A, 43c). 43B and 43C) are formed under different formation conditions.

  The optical member for measurement according to the second embodiment includes a pattern formation region (44) where the measurement pattern (46) is formed and a pattern non-formation region (positioned at a position different from the pattern formation region (44)). 45c), a measurement pattern unit (43C), a shielding part (60) capable of shielding the radiation beam (EL) incident on the pattern non-formation region (45c), and the shielding part (60). And a driving unit (61) for driving.

  The mask according to the third embodiment is arranged at a position different from the first area (70A) where the predetermined pattern is formed and the first area (70A), and the measurement pattern (46) is formed. A plurality of measurement pattern units (43A, 43B, 43C) having a pattern formation region (44) and a pattern non-formation region (45, 45a, 45b, 45c) arranged at a position different from the pattern formation region (44). ) In which the pattern non-formation regions (45, 45a, 45b, 45c) are different from each other for each of the measurement pattern units (43A, 43B, 43C). The gist is to be formed.

  In an exposure apparatus according to the fourth embodiment, an image of a pattern formed by illuminating a mask (R) on which a predetermined pattern is formed with a radiation beam (EL) emitted from an illumination optical system (15). In the exposure apparatus (11) that projects onto the substrate (W) via the projection optical system (17), a plurality of measurement units in which measurement pattern units (43A, 43B, 43C) having the measurement pattern (46) are formed are formed. When any one of the measurement optical members (23B, 23C, 23D) and the plurality of measurement optical members (23B, 23C, 23D) is arranged in the optical path of the radiation beam (EL) Measurement using a radiation beam (EL) emitted from the measurement pattern unit (43A, 43B, 43C) of any one of the measurement optical members to the projection optical system (17) side. The plurality of measurement pattern units (43A, 43B, 43C) include a pattern formation region (44) in which the measurement pattern (46) is formed and the pattern formation region (44). The pattern non-formation regions (45, 45a, 45b, 45c) are arranged at positions different from those of the pattern non-formation regions (45, 45a, 45b, 45c). , 43B, 43C) are formed under different formation conditions.

  In an exposure apparatus according to the fifth embodiment, an image of a pattern formed by illuminating a mask (R) on which a predetermined pattern is formed with a radiation beam (EL) emitted from an illumination optical system (15). In the exposure apparatus (11) that projects onto the substrate (W) via the projection optical system (17), the pattern formation region (44) on which the measurement pattern (46) is formed and the pattern formation region (44) A measurement optical member (23E) in which a measurement pattern unit (43C) having pattern non-formation regions (45c) arranged at different positions is formed, and the measurement optical arranged in the optical path of the radiation beam (EL) An adjustment device (25) for adjusting the light intensity distribution of the radiation beam (EL) that illuminates the pattern non-formation region (45c) of the member (23E), and the measurement pattern unit (43C) When arranged in the optical path of the radiation beam (EL), a measuring device (50, 50) that uses the radiation beam (EL) emitted from the measurement pattern unit (43C) to the projection optical system (17) side. SE3).

  In the exposure method according to the sixth embodiment, a mask (R) on which a predetermined pattern is formed is illuminated with a radiation beam (EL) emitted from an illumination optical system (15), and the mask (R) is passed through the mask (R). Radiation emitted from the illumination optical system (15) in the exposure method of exposing the substrate (W) by guiding the emitted radiation beam (EL) to the substrate (W) through the projection optical system (17). A measurement pattern unit (43A, 43B, 43C) having a measurement pattern is disposed in the optical path of the beam (EL), and the measurement pattern unit (43A, 43B, 43C) is directed to the projection optical system (17) side. In the case of performing measurement using the emitted radiation beam (EL), the projection optical system (17) in a state before performing measurement using the measurement pattern unit (43A, 43B, 43C). The amount of incident radiation beam (EL) is estimated, and the amount of radiation beam (EL) based on the estimation result is transmitted to the projection optical system (17) via the measurement pattern units (43A, 43B, 43C). The gist is to perform measurement using the radiation beam (EL) incident on the projection optical system (17).

  In addition, in order to explain the aspect of this invention clearly, it demonstrated corresponding to the code | symbol of drawing which shows embodiment, but it cannot be overemphasized that the aspect of this invention is not limited to embodiment.

1 is a schematic block diagram that shows an exposure apparatus according to a first embodiment. The top view which shows a slit apparatus typically. (A) is a top view which shows typically the optical member for a measurement in 1st Embodiment, (b) is arrow sectional drawing in Fig.3 (a), (c) is an example of the pattern for a measurement in a pattern formation area | region. FIG. The block diagram which shows the principal part of the electrical structure of exposure apparatus. (A) and (b) are timing charts for explaining changes in the heat storage amount and focus position of the projection optical system when a conventional measurement optical member is used. (A) and (b) are timing charts for explaining changes in the heat storage amount and focus position of the projection optical system when the measurement optical member of the first embodiment is used. The top view which shows typically the optical member for a measurement in 2nd Embodiment. The top view explaining a mode that the shielding part of the optical member for measurement shielded the pattern non-formation area | region. The side view which shows typically the principal part of the reticle stage in 3rd Embodiment. The top view which shows typically the relationship between the optical member for a measurement and slit apparatus in 4th Embodiment. The top view which shows typically the reticle in 5th Embodiment. The top view which shows typically the reticle in 6th Embodiment. (A) (b) (c) is sectional drawing which shows typically the pattern non-formation area | region of another embodiment. The flowchart of the manufacture example of a device. The detailed flowchart regarding the board | substrate process in the case of a semiconductor device.

(First embodiment)
Below, one Embodiment of this invention is described based on FIGS. In this embodiment, the direction parallel to the optical axis of the projection optical system is the Z-axis direction, and the scanning direction of the reticle R and wafer W during scanning exposure in a plane perpendicular to the Z-axis direction is the Y-axis direction. The non-scanning direction orthogonal to the scanning direction will be described as the X-axis direction. The rotation directions around the X, Y, and Z axes are also referred to as the θx direction, the θy direction, and the θz direction.

  As shown in FIG. 1, an exposure apparatus 11 according to this embodiment uses extreme ultraviolet light, ie, EUV (Extreme Ultraviolet) light, which is a soft X-ray region having a wavelength of about 100 nm or less, emitted from a light source device 12 as exposure light. It is an EUV exposure apparatus used as an EL. Such an exposure apparatus 11 includes a chamber 13 (a portion surrounded by a two-dot chain line in FIG. 1) whose inside is set to a vacuum atmosphere lower than the atmosphere, and the light source device is connected to the chamber 13 via a connecting portion 14. 12 is connected. In the chamber 13, an illumination optical system 15, a reticle stage 16 that holds the reflective reticle R, a projection optical system 17, and a wafer stage 18 that holds the wafer W are provided.

  The illumination optical system 15 is an optical system that emits the exposure light EL supplied into the chamber 13 from the light source device 12 through the connecting portion 14 to the reticle R side. Similar to the interior of the chamber 13, the illumination optical system 15 includes a casing 19 (a portion surrounded by a solid line in FIG. 1) whose interior is set to a vacuum atmosphere. A plurality of reflection mirrors (not shown) that can reflect the exposure light EL are provided in the housing 19. Then, the exposure light EL sequentially reflected by the respective reflection mirrors is incident on a reflection mirror 20 for folding that is installed in a lens barrel 26 described later, and the exposure light EL reflected by the reflection mirror 20 is on the reticle stage 16 side. Led to.

  The reticle stage 16 is disposed on the object plane side of the projection optical system 17 and includes a first electrostatic chucking holding device 21 for electrostatically chucking the reticle R. The first electrostatic adsorption holding device 21 has a base 22 made of a dielectric material and a plurality of electrode portions (not shown) arranged in the base 22. When a voltage is applied to each electrode unit from a voltage application unit (not shown), a Coulomb force is generated from the substrate 22, thereby causing the adsorption surface 22 a of the substrate 22 (the lower surface in FIG. The reticle R is electrostatically attracted to the surface in the Z direction.

  The reticle stage 16 includes a first light amount sensor SE1 for detecting the light amount of the exposure light EL emitted from the illumination optical system 15, and a reflective measurement mark used for baseline check and aerial image measurement. And the optical member for measurement 23 on which is formed. The first light quantity sensor SE1 is arranged on the −Y direction side (left side in FIG. 1) of the reticle R, and the measurement optical member 23 is arranged on the −Y direction side of the first light quantity sensor SE1. The measurement mark formed on the measurement optical member 23 includes a reticle fiducial mark (RFM), and the measurement surface 23a (the surface on the −Z direction side) of the measurement optical member 23 is held by the first electrostatic adsorption. The reticle R is electrostatically attracted to the apparatus 21 and is located at substantially the same position in the Z-axis direction as the pattern forming surface Ra (the surface on which the predetermined pattern is formed and the surface on the −Z direction side).

  The reticle stage 16 can be moved in the Y-axis direction by driving the reticle side driving device 24. The reticle side driving device 24 can move the reticle R held by the first electrostatic attraction holding device 21 with a predetermined stroke in the Y-axis direction. In addition, the reticle side driving device 24 can finely move the reticle R in the X-axis direction (direction orthogonal to the paper surface in FIG. 1), the Z-axis direction, and the θz direction.

  Between the reticle stage 16 and the lens barrel 26 of the projection optical system 17, a slit device 25 (described in detail in FIG. 2) for adjusting the light intensity distribution of the exposure light EL that illuminates the reticle R is provided. ing. The illumination region formed on the pattern forming surface Ra of the reticle R by the exposure light EL through the slit device 25 is substantially extended in the X-axis direction although its shape or position is corrected by driving the slit device 25. It is formed in an arc shape.

  The projection optical system 17 is an optical system that reduces an image of a pattern formed by illuminating the reticle R with exposure light EL to a predetermined reduction magnification (for example, 1/4 times). Similar to the interior of the chamber 13, the projection optical system 17 includes a lens barrel 26 whose interior is set to a vacuum atmosphere. A plurality of reflection mirrors 27 (six as an example, only one is shown in FIG. 1) are accommodated in the lens barrel 26. These mirrors 27 are supported by the lens barrel 26 via a holding device (not shown). The holding device is driven to move the mirror 27 in the six-degree-of-freedom directions of the X-axis direction, the Y-axis direction, the Z-axis direction, the θx direction, the θy direction, and the θz direction. Then, the exposure light EL that has entered the lens barrel 26 from the reticle R side is sequentially reflected by the mirrors 27, and the exposure surface Wa that is a wafer surface coated with a photosensitive material on the wafer W held on the wafer stage 18. (+ Z direction side surface).

A reflective layer, which is a multilayer film in which molybdenum (Mo) and silicon (Si) are alternately stacked, is formed on the reflective surface of each mirror constituting each optical system 15 and 17.
The temperature of the lens barrel 26 and each mirror 27 of the projection optical system 17 is adjusted to a predetermined temperature by a cooling mechanism (not shown). This cooling mechanism has a flow line (not shown) for flowing a cooling fluid whose temperature is adjusted to a predetermined temperature. As an example, the predetermined temperature is substantially the same as the temperature of the environment where the exposure apparatus 11 is installed.

  The wafer stage 18 includes a second electrostatic chucking holding device 28 for electrostatically chucking the wafer W. The second electrostatic chucking and holding device 28 includes a base 29 made of a dielectric material and a plurality of electrode portions (not shown) disposed in the base 29. When a voltage is applied to each electrode unit from a voltage application unit (not shown), a Coulomb force is generated from the substrate 29, so that the wafer W is statically placed on the suction surface 29 a (surface on the + Z direction side) of the substrate 29. Electroadsorbed. The wafer stage 18 includes a wafer holder (not shown) that holds the second electrostatic chucking holding device 28, and a Z leveling (not shown) that adjusts the position of the wafer holder in the Z-axis direction and the tilt angles around the X-axis and the Y-axis. And built-in mechanism.

  Further, the wafer stage 18 holds a second light amount sensor SE2 for detecting the light amount of the exposure light EL emitted from the projection optical system 17, and a measurement sensor SE3 used at the time of aerial image measurement. The second light quantity sensor SE2 is arranged on the + Y direction side of the wafer W, and the measurement sensor SE3 is arranged on the + Y direction side of the second light quantity sensor SE2. The measurement sensor SE3 is for measuring an image of the measurement mark on the measurement optical member 23 of the reticle stage 16 illuminated with the exposure light EL via the projection optical system 17.

  Further, the wafer stage 18 can be moved in the Y-axis direction by the wafer side driving device 30. The wafer-side drive device 30 can move the wafer W held by the second electrostatic chuck holding device 28 with a predetermined stroke in the Y-axis direction. Further, the wafer-side drive device 30 can move the wafer W held by the second electrostatic chuck holding device 28 with a predetermined stroke in the X-axis direction and can finely move it in the Z-axis direction. is there.

  When the pattern of the reticle R is formed on one shot area of the wafer W, the reticle R is moved in the Y-axis direction by driving the reticle side driving device 24 in a state where the illumination optical system 15 forms the illumination area on the reticle R. The projection optical system 17 moves the wafer W along the Y axis direction of the reticle R by moving the wafer side drive device 30 (for example, from the + Y direction side to the −Y direction side) for every predetermined stroke. Are moved synchronously in the Y-axis direction (for example, from the −Y direction side to the + Y direction side) at a speed ratio corresponding to the reduction magnification. When the pattern formation on one shot area is completed, the pattern formation on the other shot areas of the wafer W is continuously performed.

Next, the slit device 25 will be described. FIG. 2 is a plan view showing a schematic configuration when the slit device 25 is viewed from the reticle stage 16 side.
As shown in FIG. 2, the slit device 25 is a device for adjusting the position or shape of the illumination area formed on the pattern forming surface Ra of the reticle R, and is conjugated to the pattern forming surface Ra, that is, the image surface. It is arranged near the position. The slit device 25 includes a fixed blade 35 disposed on the + Y direction side (right side in FIG. 3) and a plurality of sheets (only 12 are illustrated in FIG. 3) disposed on the −Y direction side (left side in FIG. 3). The movable blade 36 is provided. These fixed blades 35 and the movable blades 36 can block at least a part of the exposure light EL incident thereon. The fixed blade 35 is made of a plate material arranged substantially parallel to the XY plane, and is formed so that a portion on the + Y direction side has a substantially arc shape. Each movable blade 36 is arranged in the X-axis direction orthogonal to the Y-axis direction.

  The slit device 25 is provided with a plurality of (in FIG. 3, 12) actuators 37 that individually correspond to each movable blade 36. These actuators 37 are connected to individually corresponding movable blades 36 via rod members 38. The movable blade 36 connected to the driving actuator 37 via the rod member 38 moves forward and backward in the Y-axis direction, which is a direction crossing the optical path of the exposure light EL that illuminates the reticle R. By individually adjusting the position of each movable blade 36 in the Y-axis direction, the shape or position of the illumination area formed on the pattern forming surface Ra can be adjusted.

Next, the measurement optical member 23 will be described. FIG. 3A is a plan view showing a schematic configuration when the measuring optical member 23 is viewed from the lens barrel 26 side.
As shown in FIGS. 3A and 3B, the measurement optical member 23 includes a substantially rectangular parallelepiped base member 40 made of a low thermal expansion member (low thermal expansion glass as an example). The base member 40 may be formed of the same material as the reticle R. A reflective layer 41 that reflects the exposure light EL is formed on the first surface 40a (the surface in the −Z direction, which is the upper surface in FIG. 3B) of the base member 40. In addition, an absorption layer 42 that absorbs the exposure light EL is formed on the upper surface of a region of the reflection layer 41 formed on the first surface 40a that does not reflect the exposure light EL and absorbs the exposure light EL. As an example, the reflective layer 41 is a multilayer film in which molybdenum (Mo) and silicon (Si) are alternately stacked, and reflects most of the incident exposure light EL (about 70% as an example). The absorption layer 42 can be formed of a single thin film using chromium, stainless steel, aluminum, gold, lead, or the like, or a multilayer film in which these are laminated in combination. The absorbing layer 42 is formed on the upper surface of the reflective layer 41 by using a mask or the like to cover a region of the reflective layer 41 formed on the first surface 40a where the exposure light EL is to be reflected. be able to.

  On the measurement surface 23a side of the measurement optical member 23, a plurality (three in the present embodiment) of measurement pattern units 43A, 43B, and 43C arranged in the Y-axis direction are formed. The shape of the measurement pattern units 43A, 43B, and 43C is a shape corresponding to the illumination area of the reticle R or the measurement optical member 23 formed by illumination with the exposure light EL (in the present embodiment, the shape extending substantially in the X-axis direction). Arc). In the present embodiment, the measurement pattern units 43A, 43B, and 43C have different reflectances. The reflectance is the ratio of the reflected light beam reflected by the measurement pattern units 43A, 43B, and 43C to the incident light beam of the exposure light EL that enters the measurement pattern units 43A, 43B, and 43C. Further, the ratio of the amount of reflected light reflected by the measurement pattern units 43A, 43B, and 43C to the amount of incident light of the exposure light EL that enters the measurement pattern units 43A, 43B, and 43C may be used as the reflectance. As the measurement pattern unit has a higher reflectance, the amount of exposure light EL incident on the projection optical system 17 can be increased.

  The measurement pattern units 43A, 43B, and 43C have a configuration in which the pattern formation regions 44 and the pattern non-formation regions 45 (45a, 45b, and 45c) are alternately arranged along the X-axis direction. In the pattern formation region 44, as shown in FIG. 3C, a plurality of types of measurement patterns 46 are formed. The measurement pattern 46 is formed by a plurality of lines extending in various directions and spaces between the lines. Examples of the measurement pattern 46 include a space image measurement pattern and a baseline check pattern.

  The plurality of lines of the measurement pattern 46 are formed by the reflective layer 41 and reflect the exposure light EL. The space between the lines is formed by the absorption layer 42 and absorbs the exposure light EL. In FIG. 3C, a region 46A different from the measurement pattern 46 in the pattern formation region 44 is formed by the reflective layer 41 and is a portion that can reflect the exposure light EL.

  In each of the measurement pattern units 43A, 43B, and 43C, the configurations of the pattern formation regions 44 that constitute them are substantially the same. On the other hand, the pattern non-formation regions 45a, 45b, and 45c are configured under different formation conditions for each of the measurement pattern units 43A, 43B, and 43C.

  Among the measurement pattern units 43A, 43B, and 43C, the formation condition of the pattern non-formation region 45a of the first measurement pattern unit 43A located closest to the −Y direction is the exposure that has entered the pattern non-formation region 45a. This is a condition that almost absorbs light EL. For example, in the pattern non-formation region 45a, the first portion 47A that can reflect the incident exposure light EL toward the projection optical system 17 side is not provided, but the second portion 47B that absorbs the exposure light EL is provided. .

  The formation condition of the pattern non-formation region 45b of the second measurement pattern unit 43B located on the + Y direction side of the first measurement pattern unit 43A is that of the exposure light EL incident on the pattern non-formation region 45b. This is a condition for reflecting the part. For example, the pattern non-formation region 45b has a configuration in which a first portion 47A for emitting the incident exposure light EL to the projection optical system 17 side and a second portion 47B for absorbing the exposure light EL are provided. In this case, the exposure light EL reflected by the first portion 47A out of the exposure light EL incident on the pattern non-formation region 45b enters the projection optical system 17. In other words, it can be said that the formation condition of the pattern non-formation region 45b is such that the reflectance of the incident exposure light EL toward the projection optical system 17 is higher than the reflectance of the pattern non-formation region 45a. . As an example, the area ratio of the first portion 47A in the pattern non-formation region 45b is approximately 50%. As shown in FIG. 3B, the first portion 47A has a reflective layer 41 and reflects the exposure light EL.

  The formation condition of the pattern non-formation region 45c of the third measurement pattern unit 43C located closest to the + Y direction side is that the reflectance of the incident exposure light EL toward the projection optical system 17 side is that of the pattern non-formation region 45b. The conditions are such that the reflectance is higher. For example, the pattern non-formation region 45c has a configuration in which the first portion 47A is provided but the second portion 47B is not provided. That is, the reflectances of the measurement pattern units 43A, 43B, and 43C are different from each other due to the difference in reflectance in the pattern non-formation regions 45a, 45b, and 45c.

  In this embodiment, the measurement pattern units 43A, 43B, and 43C are arranged along the Y-axis direction in the order of reflectivity. However, the measurement pattern units 43C having the highest reflectivity are arranged in the middle. May be. That is, each measurement pattern unit 43A, 43B, 43C may be arbitrarily changed.

Next, the control device 50 that controls the exposure apparatus 11 of the present embodiment will be described.
As shown in FIG. 4, the control device 50 is electrically connected to the first light quantity sensor SE1, the second light quantity sensor SE2, and the measurement sensor SE3. The control device 50 detects the light quantity of the exposure light EL emitted to the reticle stage 16 side based on the detection signals from the light quantity sensors SE1 and SE2, and the exposure light EL emitted to the wafer stage 18 side. Detect the amount of light.

  The control device 50 includes a control unit 51 including a CPU, ROM, and RAM (not shown), a reticle side drive circuit 52 for driving the reticle side drive device 24, and a slit for driving the slit device 25. A driving circuit 53 and a wafer side driving circuit 54 for driving the wafer side driving device 30 are provided. Then, the control unit 51 controls driving of the reticle side driving device 24, the slit device 25, and the wafer side driving device 30 via the drive circuits 52 to 54. Although not shown, the control device 50 controls the drive of a holding device (not shown) for each mirror 27 in order to adjust the position and shape of each mirror 27 constituting the projection optical system 17.

  The control unit 51 according to the present embodiment estimates the light amount of the exposure light EL that enters the projection optical system 17 from the reticle R side based on the detection signals from the light amount sensors SE1 and SE2. For example, the control unit 51 has the light quantity of the exposure light EL emitted from the illumination optical system 15 based on the detection signal from the first light quantity sensor SE1 in a state where the first light quantity sensor SE1 is arranged in the optical path of the exposure light EL. (Hereinafter also referred to as the first light quantity) is calculated. The first light amount is the light amount of the exposure light EL that illuminates the reticle R. Further, the control unit 51, based on the detection signal from the second light quantity sensor SE2 in a state where the reticle R is arranged in the optical path of the exposure light EL and the second light quantity sensor SE2 is arranged in the optical path of the exposure light EL, A light amount (also referred to as a second light amount) of the exposure light EL emitted from the projection optical system 17 is calculated. Based on the second light amount and the estimated loss amount of the exposure light EL by the projection optical system 17, the control unit 51 determines the amount of exposure light EL that enters the projection optical system 17 from the reticle R side during the exposure process (hereinafter referred to as the light amount). , Also referred to as third light quantity).

  Note that the estimated loss amount of the exposure light EL by the projection optical system 17 is, for example, the loss amount estimated from the number of mirrors 27 constituting the projection optical system 17 and the reflection characteristics of each mirror 27, This is a loss amount calculated by making the exposure light EL incident on the projection optical system 17 and measuring the amount of the exposure light EL that has passed through the projection optical system 17. Thereby, the control unit 51 can estimate the reflectance of the reticle R from the ratio of the third light quantity to the first light quantity. These calculation results and estimation results can be used when selecting the measurement pattern units (43A, 43B, 43C) to be illuminated. In the present embodiment, the control unit 51 is configured to estimate the third light amount, but is not limited thereto. A light amount sensor may be provided in the optical path between the reticle R and the projection optical system 17 to measure the third light amount. For example, this light quantity sensor is a movable sensor installed in the optical path between the reticle R and the projection optical system 17 when measuring the third light quantity.

  In addition, when the measurement optical member 23 is installed in the optical path of the exposure light EL instead of the reticle R and the measurement sensor SE3 is installed in the optical path of the exposure light EL instead of the wafer W, the control device 50 Based on the detection signal from the measurement sensor SE3, the aerial image of the measurement pattern 46 of the measurement pattern units (43A, 43B, 43C) is measured. Then, the control device 50 calculates the optical characteristics of the projection optical system 17 based on the observation result.

  The exposure apparatus 11 of the present embodiment measures and adjusts the optical characteristics of the projection optical system 17 using the measurement optical member 23 before starting the exposure process on the wafer W and during the exposure process. Yes.

  Therefore, next, an exposure method when performing exposure processing on the wafer W while performing measurement processing using the measurement optical member 23 will be described with reference to timing charts of FIGS. Note that the timing chart shown in FIG. 5 is a timing chart in the case of performing measurement using the measurement optical member having only the first measurement pattern unit 43A. On the other hand, the timing chart shown in FIG. 6 is a timing chart when performing measurement using the measurement optical member 23 of the present embodiment.

  First, a case where measurement is performed using a measurement optical member having only the first measurement pattern unit 43A will be described. Here, as an example of the optical characteristics of the projection optical system 17, the measurement of the position of the aerial image formed by the projection optical system 17, that is, the focus position of the projection optical system 17 will be described as an example.

  As shown in FIGS. 5A and 5B, in order to perform measurement processing using the measurement optical member before the exposure processing to the wafer W is started, the measurement optical member is the reticle side driving device 24. Thus, instead of the reticle R, it is arranged in the optical path of the exposure light EL. At the same time, the measurement sensor SE3 is arranged in the optical path of the exposure light EL by the wafer side driving device 30. In this state, when the exposure light EL is incident on the measurement optical member from the illumination optical system 15, a part of the exposure light EL reflected by the measurement optical member is incident on the measurement sensor SE3 via the projection optical system 17. . That is, the aerial image formed by the exposure light EL entering the first measurement pattern unit 43A formed on the measurement optical member is observed by the measurement sensor SE3 (first timing t11).

  The first measurement pattern unit 43A reflects a very small amount of the exposure light EL incident on the first measurement pattern unit 43A toward the projection optical system 17 side. Therefore, the heat storage amount Pe of the projection optical system 17 whose temperature is adjusted by a cooling mechanism (not shown) is maintained at approximately 0 (zero). As a result, at the first timing t11, the focus position of the projection optical system 17 in the initial state is measured based on the observation result of the measurement sensor SE3.

  When the measurement is performed at the first timing t11, the projection optical system 17 is set so that the focus position of the projection optical system 17 coincides with the best focus position KF corresponding to the installation position of the exposure surface Wa of the wafer W. Adjusted. Specifically, the spacing in the Z-axis direction of each mirror 27 constituting the projection optical system 17 is adjusted by a holding device (not shown) for each mirror 27. At this time, the position of the wafer stage 18 in the Z-axis direction may be adjusted. When the focus position of the projection optical system 17 is adjusted to the best focus position KF, the reticle R is placed in the optical path of the exposure light EL by the reticle side driving device 24 and the wafer W is driven by the wafer side driving device 30. One shot area among the shot areas formed is arranged in the optical path of the exposure light EL. In this state, the exposure light EL is emitted from the illumination optical system 15, whereby the exposure processing for the wafer W is started (second timing t12).

  When the exposure process on the wafer W is started, the reflectance of the exposure light EL on the reticle R is higher than the reflectance of the exposure light EL on the first measurement pattern unit 43A. The amount of light EL increases as compared to the measurement using the first measurement pattern unit 43A. As a result, the heat storage amount Pe of the projection optical system 17 on which the exposure light EL is incident via the reticle R increases with time. That is, the heat storage amount of the lens barrel 26 and each mirror 27 constituting the projection optical system 17 increases. Then, the position of each mirror 27 is displaced, or each mirror 27 itself is slightly deformed, and the focus position of the projection optical system 17 is gradually displaced from the best focus position KF.

  Thereafter, when a substantially constant amount of exposure light EL continues to enter the projection optical system 17 from the reticle R side, a steady state is reached in which the difference between the heat absorption amount of the projection optical system 17 and the heat dissipation amount by the cooling mechanism is constant ( Third timing t13). Then, the heat storage amount Pe of the projection optical system 17 becomes stable, and the focus position of the projection optical system 17 becomes stable.

  In order to perform measurement during the exposure process, the exposure process is temporarily interrupted, and the measurement optical member and the measurement sensor SE3 are installed in the optical path of the exposure light EL instead of the reticle R and the wafer W (fourth). Timing t14). Then, since the reflectance of the first measurement pattern unit 43A of the measurement optical member is lower than that of the reticle R, the exposure light EL that enters the projection optical system 17 via the first measurement pattern unit 43A. Is less than that in the case where the exposure light EL enters the projection optical system 17 via the reticle R. That is, the endothermic amount of the projection optical system 17 is reduced. Therefore, the heat storage amount Pe of the projection optical system 17 cooled by the cooling mechanism gradually decreases as the heat absorption amount of the projection optical system 17 decreases. That is, since the amount of heat stored in the lens barrel 26 and each mirror 27 constituting the projection optical system 17 is also reduced, the position and shape of each mirror 27 gradually returns to the state before the start of the exposure process. As a result, the focus position of the projection optical system 17 gradually approaches the best focus position KF (fifth timing t15). When the measurement is performed at the fifth timing t15, the projection optical system 17 is readjusted so that the focus position of the projection optical system 17 becomes the best focus position KF at the subsequent sixth timing t16. During the readjustment of the projection optical system 17, the reticle R and the wafer W are rearranged in the optical path of the exposure light EL.

  However, the readjustment of the projection optical system 17 is performed based on the measurement result at the fifth timing t15. Therefore, even at the sixth timing t16 when the focus position of the projection optical system 17 is actually adjusted, the heat storage amount Pe of the projection optical system 17 changes between the fifth timing t15 and the sixth timing t16. Therefore, the focus position of the projection optical system 17 is slightly different from the best focus position KF.

  When the exposure process is resumed from the sixth timing t16, the amount of exposure light EL that enters the projection optical system 17 increases again. For this reason, the heat storage amount Pe of the projection optical system 17 increases with time, and as a result, the focus position of the projection optical system 17 is displaced so as to be separated from the best focus position KF again. Therefore, even if the optical characteristics of the projection optical system 17 using the measurement optical member are measured during the exposure process, and the optical characteristics of the projection optical system 17 are corrected based on the measurement results, There is a possibility that the optical characteristics of the projection optical system 17 gradually change from the best state.

Next, a case where measurement is performed using the measurement optical member 23 of the present embodiment will be described.
As shown in FIGS. 6A and 6B, when measuring the projection optical system 17 using the measurement optical member 23 before the start of the exposure process, the measurement optical member is measured by the reticle side driving device 24. 23 is arranged in the optical path of the exposure light EL. At this time, since the exposure light EL is not incident on the projection optical system 17 in the state before the measurement, the first measurement pattern unit 43A having the lowest reflectance among the measurement pattern units 43A to 43C is exposed. It arrange | positions to the optical path of light EL (1st timing t21). At the same time, the measurement sensor SE3 is arranged in the optical path of the exposure light EL by the wafer side driving device 30. When the focus position of the projection optical system 17 is adjusted based on the measurement result here, the reticle R and the wafer W are respectively arranged in the optical path of the exposure light EL, and the exposure process is started (second timing t22). . It is assumed that the shape, light intensity, light amount, etc. of the exposure light EL do not change before and after the timing t22.

  Then, since the reflectance of the reticle R is higher than the reflectance of the first measurement pattern unit 43A, the heat storage amount Pe of the projection optical system 17 increases with the passage of time, and the focus position of the projection optical system 17 changes to the time. Displaces over time. Then, the exposure process is temporarily interrupted at the third timing t23 when the difference between the heat absorption amount of the projection optical system 17 and the heat dissipation amount by the cooling mechanism becomes constant and the focus position of the projection optical system 17 is stable. Then, the focus position of the projection optical system 17 is measured. At this time, before the measurement optical member 23 and the measurement sensor SE3 are arranged in the optical path of the exposure light EL, the reflectance of the reticle R used during the exposure process is estimated using the light quantity sensors SE1 and SE2. . Based on the estimation result, the measurement pattern unit closest to the reflectance of the reticle R (for example, the second measurement pattern unit 43B) is selected from the measurement pattern units 43A to 43C. Then, the selected second measurement pattern unit 43B and measurement sensor SE3 are arranged in the optical path of the exposure light EL. At this time, the third measurement pattern unit 43C may be selected depending on the shape of the pattern formed on the reticle R, that is, the reflectance of the reticle R.

  Then, unlike the case where only the first measurement pattern unit 43A is provided, the amount of exposure light EL incident into the projection optical system 17 is the same as that during measurement using the second measurement pattern unit 43B and the reticle R. Almost the same as the exposure processing used (fourth timing t24). Further, the heat storage amount Pe and the focus position of the projection optical system 17 hardly change before and after the third timing t23. Therefore, in the present embodiment, the focus position of the projection optical system 17 during the exposure process is measured more accurately. Then, the deviation amount between the current focus position and the best focus position KF is measured by the control unit 51 of the control device 50, and the projection optical system 17 is readjusted based on the measurement result (fifth timing t25).

  Thereafter, when the measurement optical member 23 and the measurement sensor SE3 are retracted out of the optical path of the exposure light EL, and the reticle R and the wafer W are rearranged in the optical path of the exposure light EL, the exposure process is resumed. At this time, since the steady state of the heat storage amount Pe of the projection optical system 17 is continued, the focus position of the projection optical system 17 is not displaced from the best focus position KF. Even if the focus position is displaced, the amount of displacement is very small compared to the case where the measurement optical member having only the first measurement pattern unit 43A is used. Therefore, a pattern having a more appropriate shape is formed on the wafer W after the fifth timing t25.

Therefore, in this embodiment, the following effects can be obtained.
(1) The measurement optical member 23 of the present embodiment includes a plurality of measurement pattern units 43A to 43C having different reflectivities. Then, by arranging an appropriate measurement pattern unit in the optical path of the exposure light EL according to the situation, the optical characteristic (focus position as an example) of the projection optical system 17 can be appropriately measured.

  (2) Before the start of the exposure process, the amount of exposure light EL incident on the projection optical system 17 from the reticle R side is 0 (zero). For this reason, at the time of measurement before the start of the exposure process, the first measurement pattern unit 43A having the lowest reflectance is arranged in the optical path of the exposure light EL, and the projection optical system 17 is used by using the first measurement pattern unit 43A. The optical characteristics are measured. Therefore, the optical characteristics of the projection optical system 17 before the start of exposure can be accurately measured.

  (3) When measurement is performed during the exposure process, a measurement pattern unit having a reflectance closest to the reflectance of the reticle R used during the exposure process is arranged in the optical path of the exposure light EL. Therefore, fluctuations in the heat storage amount Pe of the projection optical system 17 during exposure processing and measurement can be suppressed as much as possible, and fluctuations in the optical characteristics (for example, the focus position) of the projection optical system 17 can be suppressed as much as possible. it can. Therefore, the optical characteristics of the projection optical system 17 during the exposure process can be measured more accurately.

  (4) Further, the improvement in the measurement accuracy of the optical characteristics of the projection optical system 17 during the exposure process has improved the correction accuracy of the optical characteristics of the projection optical system 17 based on the measurement results. Therefore, it is possible to improve the pattern formation accuracy on the wafer W after the restart of the exposure process.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment differs from the first embodiment in the configuration of the measurement optical member. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  As shown in FIGS. 7 and 8, the measurement optical member 23 </ b> A of this embodiment includes one measurement pattern unit 43 </ b> C. The pattern non-formation region 45c of the measurement pattern unit 43C has the first portion 47A that can reflect the exposure light EL, but does not have the second portion 47B that cannot reflect the exposure light EL. In addition, the measurement optical member 23A moves the shield 60 forward and backward in the Y-axis direction, which is a direction crossing the optical path of the exposure light EL that illuminates the reticle R, and the shield 60 disposed on the measurement surface 23a side. The drive part 61 is provided. The shield 60 can shield each pattern non-formation region 45c of the measurement pattern unit 43C and absorbs the incident exposure light EL. The drive unit 61 is electrically connected to the control device 50 of the exposure apparatus 11. Then, the driving unit 61 drives the shielding unit 60 to move in accordance with a driving signal input from the control device 50.

  For example, at the time of measurement before the exposure process, the drive unit 61 arranges the shielding unit 60 on the most + Y direction side (see FIG. 8). Then, the exposure light EL hardly enters the pattern non-formation region 45c of the measurement pattern unit 43C. Further, the drive unit 61 adjusts the position of the shielding unit 60 in the Y-axis direction based on the reflectance of the reticle R used for the exposure process during measurement with the exposure process interrupted. That is, the measurement optical member 23A of the present embodiment adjusts the amount of the exposure light EL incident on the pattern non-formation region 45c of the measurement pattern unit 43C to move from the measurement pattern unit 43C to the projection optical system 17 side. The amount of reflected exposure light EL can be adjusted.

Therefore, in this embodiment, the following effects can be obtained.
(5) In the measurement optical member 23A of the present embodiment, by driving the drive unit 61, the incident amount of the exposure light EL to the projection optical system 17 side via the measurement pattern unit 43C is appropriate depending on the situation. Adjusted to Therefore, it is possible to appropriately measure the optical characteristics (for example, the focus position) of the projection optical system 17.

  (6) Before the start of the exposure process, the amount of exposure light EL that enters the projection optical system 17 from the reticle R side is 0 (zero). Therefore, at the time of measurement before the start of the exposure process, the optical characteristics of the projection optical system 17 are measured in a state where the entire pattern non-formation region 45c of the measurement pattern unit 43C is covered by the shielding unit 60. Therefore, the optical characteristics of the projection optical system 17 before the start of exposure can be accurately measured.

  (7) When measurement is performed during the exposure process, the amount of exposure light EL incident on the projection optical system 17 side via the reticle R used during the exposure process is measured via the measurement pattern unit 43C. The position of the shielding unit 60 in the Y-axis direction is adjusted so that the amount of exposure light EL incident on the projection optical system 17 side matches or approaches. In such a state, the optical characteristics of the projection optical system 17 are measured using the measurement optical member 23A. Therefore, fluctuations in the heat storage amount Pe of the projection optical system 17 during exposure processing and measurement can be suppressed as much as possible, and fluctuations in the optical characteristics of the projection optical system 17 can be suppressed as much as possible. Therefore, the optical characteristics of the projection optical system 17 during the exposure process can be measured more accurately.

  (8) Further, by improving the measurement accuracy of the optical characteristics of the projection optical system 17 during the exposure process, the correction accuracy of the optical characteristics of the projection optical system 17 based on the measurement results is improved. Therefore, it is possible to improve the pattern formation accuracy on the wafer W after the restart of the exposure process.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the first and second embodiments in that it includes a plurality of measurement optical members. Therefore, in the following description, parts different from the first and second embodiments will be mainly described, and the same reference numerals are given to the same or corresponding member configurations as those of the first and second embodiments. A duplicate description will be omitted.

  As shown in FIG. 9, the reticle stage 16 of the present embodiment holds a plurality (three in this embodiment) of measurement optical members 23B, 23C, and 23D. These measurement optical members 23B to 23D are juxtaposed on the −Y direction side of the reticle R, and the measurement surfaces of the measurement optical members 23B to 23D are substantially in the same position as the pattern formation surface Ra of the reticle R in the Z-axis direction. Is located. Further, the measurement optical members 23B to 23D have measurement pattern units having different reflectances. As an example, the measurement optical member 23B includes the first measurement pattern unit 43A, and the measurement optical member 23C positioned on the −Y direction side of the measurement optical member 23B includes the second measurement pattern unit 43B. In addition, the measurement optical member 23D located on the −Y direction side of the measurement optical member 23C has a third measurement pattern unit 43C.

  In the exposure apparatus 11 of the present embodiment, when measuring the optical characteristics of the projection optical system 17, the measurement optical members 23B to 23D, that is, the measurement pattern units 43A to 43C used according to the previous conditions are appropriate. Selected. Therefore, in the present embodiment, it is possible to obtain substantially the same effects as the effects (1) to (4) of the first embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. Note that the fourth embodiment is different from the second embodiment in that it does not have a shielding part and a driving part. Therefore, in the following description, portions different from the first to third embodiments will be mainly described, and the same reference numerals are given to the same or corresponding member configurations as the first to third embodiments. A duplicate description will be omitted.

  As shown in FIG. 10, the measurement optical member 23E of the present embodiment includes one measurement pattern unit 43C. The pattern non-formation region 45c of the measurement pattern unit 43C has the first portion 47A that can reflect the exposure light EL, but does not have the second portion 47B that cannot reflect the exposure light EL.

  Then, when the measurement optical member 23E is disposed in the optical path of the exposure light EL, the control device 50 moves each movable blade 36 of the slit device 25 individually in the Y-axis direction, so that each pattern non-formation region The amount of exposure light EL incident on 45c is adjusted. As a result, the amount of exposure light EL that enters the projection optical system 17 via the measurement pattern unit 43C is adjusted. At the time of measurement of the measurement optical member 23E in the present embodiment, the slit device 25 can perform the same function as the shielding unit 60 in the second embodiment. Therefore, in the present embodiment, effects substantially equivalent to the effects (5) to (8) of the second embodiment can be obtained.

In FIG. 10, the illustration of the fixed blade 35 of the slit device 25 is omitted for convenience of understanding the description.
(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment is different from the first embodiment in that a plurality of measurement pattern units are formed on the reticle R. Therefore, in the following description, parts different from the first to fourth embodiments will be mainly described, and the same reference numerals are given to the same or corresponding member configurations as those of the first to fourth embodiments. A duplicate description will be omitted.

  As shown in FIG. 11, the reticle R of this embodiment includes a substantially rectangular parallelepiped base member made of a low thermal expansion member (low thermal expansion glass as an example). A reflective layer that reflects the exposure light EL is formed on the first surface side of the base member. In addition, an absorption layer is formed in a region of the first surface that absorbs the exposure light EL. As an example, the reflective layer is a multilayer film in which molybdenum (Mo) and silicon (Si) are alternately stacked.

  On the pattern forming surface Ra side of the reticle R, a first region 70A (a region surrounded by a broken line in FIG. 11) where a predetermined pattern is formed, and a substantially square annular shape located outside the first region 70A. A second region 70B is formed. In the second region 70B, a plurality of (three in the present embodiment) measurement pattern units 43A, 43B, and 43C having different reflectances are formed. As an example, the first measurement pattern unit 43A is formed in the second region 70B on the + Y direction side of the first region 70A. Further, in the second region 70B, the second measurement pattern unit 43B is formed on the −Y direction side of the first region 70A, and the second measurement pattern unit 43B in the −Y direction in the second region 70B. On the side, a third measurement pattern unit 43C is formed.

  When performing measurement using the measurement pattern unit, an appropriate measurement pattern unit is selected according to the conditions before and after the measurement. At the time of measurement, the illumination area formed by the slit device 25 may have the same shape as before and after the measurement. Therefore, in this embodiment, it is possible to obtain substantially the same effects as the effects (1) to (4) of the first and third embodiments.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment is different from the fifth embodiment in that one measurement pattern unit is formed on the reticle R. Therefore, in the following description, parts different from the first to fifth embodiments will be mainly described, and the same reference numerals are given to the same or corresponding member configurations as those of the first to fifth embodiments. A duplicate description will be omitted.

  As shown in FIG. 12, a measurement pattern unit 43C is formed in the second region 70B of the reticle R of the present embodiment. At the time of measurement by the projection optical system 17, the measurement pattern unit 43C is disposed in the optical path of the exposure light EL. In this measurement, the amount of exposure light incident on each pattern non-formation region 45c of the measurement pattern unit 43C is adjusted by the slit device 25. For example, the control device 50 individually adjusts the position of each movable blade 36 of the slit device 25 in the Y-axis direction, so that the amount of exposure light EL that enters the projection optical system 17 via the measurement pattern unit 43C. Can be adjusted. Therefore, in this embodiment, it is possible to obtain substantially the same effects as the effects (5) to (8) of the second and fourth embodiments.

In addition, you may change each said embodiment into another embodiment as follows.
In each of the fourth and sixth embodiments, an adjustment device that adjusts the amount of exposure light EL incident on each pattern non-formation region 45c of the measurement pattern unit 43C is optically coupled to the pattern formation surface Ra of the reticle R. You may arrange | position in the vicinity of a conjugate position.

  In each of the first, third, and fifth embodiments, the absorption layers 42 having different thicknesses may be formed in the pattern non-formation regions 45 (45a to 45c) of the measurement pattern units 43A to 43C. For example, FIG. 13A shows a pattern non-formation region 45a of the measurement pattern unit 43A, and FIG. 13B shows a pattern non-formation region 45b of the measurement pattern unit 43B. (C) shows the pattern non-formation region 45c of the measurement pattern unit 43C. In the pattern non-formation region 45a and the pattern non-formation region 45b, the absorption layer 42 is formed on the upper surface of the reflection layer 41, and the absorption layer 42 is not formed in the pattern non-formation region 45c. Is formed. Moreover, the thickness of the absorption layer 42 formed in the pattern non-formation region 45b is thinner than the thickness of the absorption layer 42 formed in the pattern non-formation region 45a of the measurement pattern unit 43A.

  For this reason, part of the exposure light EL that enters the pattern non-formation region 45 b reaches the reflection layer 41, is reflected by the reflection layer 41, and enters the projection optical system 17. Thereby, the reflectance of exposure light EL by the pattern non-formation area | region 45b can be made higher than the reflectance of exposure light EL by the pattern non-formation area | region 45a. As an example, the thickness of the absorption layer 42 in the pattern non-formation region 45b is approximately 50% of the thickness of the absorption layer 42 in the pattern non-formation region 45a. The thinner the absorption layer 42, the smaller the amount of exposure light EL absorbed by the absorption layer 42, and the more amount of exposure light EL reflected by the reflective layer 41. For this reason, the light quantity of the exposure light EL which enters into the projection optical system 17 can be increased. In addition, the thickness of the absorption layer 42 formed in the pattern non-formation area | region 45 (45a-45c) is not limited to these combinations. In addition, if the reflectance of the reticle R used for the exposure process is known in advance, an absorption layer 42 having a thickness that provides a reflectance equal to this reflectance may be formed in the pattern non-formation region.

  In the first, third, and fifth embodiments, the pattern non-formation regions 45 (45a to 45c) of the measurement pattern units 43A to 43C do not reflect the exposure light EL among the first surface, Although the absorption layer 42 is formed in the region that absorbs the exposure light EL, the present invention is not limited to this. An absorption layer 42 is formed on the upper surface of the reflection layer 41, and the absorption layer 42 in the region that reflects the exposure light EL is removed from the formed absorption layer 42, thereby exposing the reflection layer 41 and reflecting the exposure light EL. You may comprise. Further, the reflective layer 41 may be formed on the absorption layer 42. At this time, by forming the reflective layer 41 in the region that reflects the exposure light EL, or by removing the reflective layer 41 in the region that absorbs the exposure light EL without reflecting the exposure light EL after forming the reflective layer 41, A configuration in which the absorption layer 42 is exposed may be used. Further, the reflection layer 41 and the absorption layer 42 may be individually formed on the first surface 40 a of the base member 40. A reflective layer 41 is formed in a region of the first surface 40a of the base member 40 that reflects the exposure light EL, and the exposure light EL is not reflected on the first surface 40a of the base member 40 without reflecting the exposure light EL. An absorption layer 42 may be formed in the absorption region.

  In each of the first, third, and fifth embodiments, when the control device 50 stores in advance the reflectance of the reticle R used for the exposure process, measurement using the measurement pattern units 43A to 43C is performed. It is not necessary to estimate the reflectance of the reticle R using the light quantity sensors SE1 and SE2 before. In this case, a measurement pattern unit arranged in the optical path of the exposure light EL is selected based on information on the reticle R stored in a storage unit (not shown) of the control device 50.

  Similarly, in each of the second, fourth, and sixth embodiments, when the control device 50 stores in advance the reflectance of the reticle R used for the exposure process, the measurement pattern units 43A to 43C are stored. Prior to the measurement used, it is not necessary to estimate the reflectance of the reticle R using the light quantity sensors SE1 and SE2. In this case, the positions of the movable blades 36 and the shielding unit 60 of the slit device 25 in the Y-axis direction are adjusted based on information on the reticle R stored in a storage unit (not shown) of the control device 50.

  In each of the first, third, and fifth embodiments, the measurement pattern units 43A to 43C used for measurement may be selected by an operator using an operation unit (not shown).

  Similarly, in each of the second, fourth, and sixth embodiments, the positions of the movable blades 36 and the shielding unit 60 of the slit device 25 in the Y-axis direction at the time of measurement using the measurement pattern unit 43C are illustrated. It may be selected by an operator operating using a non-operating unit.

In each of the first, third, and fifth embodiments, the measurement pattern unit may be provided with any plural types (for example, five types) other than three having different reflectances.
In each embodiment, the measurement pattern 46 formed in one measurement pattern unit may be arranged along the circumferential direction. However, the plurality of measurement patterns 46 may be equally spaced along the circumferential direction.

  In each of the first, third, and fifth embodiments, the second portion 47B of the pattern non-formation regions 45a to 45c in each of the measurement pattern units 43A to 43C uses the exposure light EL that has entered the second portion 47B. It may be configured to reflect or diffuse in a direction different from the projection optical system 17.

In the second embodiment, the shielding unit 60 may be configured to reflect or diffuse the exposure light EL incident on the shielding unit 60 in a direction different from the projection optical system 17.
Regarding the exposure method when performing exposure processing on the wafer W while performing measurement using the measurement optical member 23 of the present embodiment, the test wafer W is used before the fifth timing t25, and after the timing t25. In addition, a wafer W for device manufacture may be used. Thereby, the wafer W for device manufacture can form a circuit pattern when the focus position of the projection optical system 17 is set to the best focus position KF.

  If a measurement pattern unit closest to the reflectance of the reticle R (for example, the second measurement pattern unit 43B) is known in advance, measurement is performed using this measurement pattern unit at timing t21. The focus position of the projection optical system 17 may be adjusted based on the measurement result. Thereby, when the exposure process is started at the timing t22, the displacement amount by which the focus position of the projection optical system 17 is displaced can be reduced.

  In each embodiment, the exposure apparatus 11 manufactures a reticle or mask used in not only a microdevice such as a semiconductor element but also a light exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, and an electron beam exposure apparatus. Therefore, an exposure apparatus that transfers a circuit pattern from a mother reticle to a glass substrate or a silicon wafer may be used. The exposure apparatus 11 is used for manufacturing a display including a liquid crystal display element (LCD) and the like, and is used for manufacturing an exposure apparatus that transfers a device pattern onto a glass plate, a thin film magnetic head, and the like. It may be an exposure apparatus that transfers to a wafer or the like, and an exposure apparatus that is used to manufacture an image sensor such as a CCD.

In each embodiment, the light source device 12 includes, for example, g-line (436 nm), i-line (365 nm), KrF excimer laser (248 nm), F ₂ laser (157 nm), Kr ₂ laser (146 nm), Ar ₂ laser (126 nm) Or the like. The light source device 12 amplifies the infrared or visible single wavelength laser light oscillated from the DFB semiconductor laser or fiber laser, for example, with a fiber amplifier doped with erbium (or both erbium and ytterbium). Alternatively, a light source capable of supplying harmonics converted into ultraviolet light using a nonlinear optical crystal may be used.

In each embodiment, a transmissive optical member for measurement may be used for the exposure apparatus 11 that uses the transmissive reticle R.
In each embodiment, the exposure apparatus 11 may be embodied as a step-and-repeat apparatus. In this case, the shape of the measurement pattern units 43A to 43C may be substantially the same as that of the first region 70A in which a predetermined pattern is formed on the reticle R.

  In each embodiment, the shape of the measurement pattern units 43 </ b> A to 43 </ b> C may be any shape as long as the shape is substantially the same as the illumination area formed on the reticle R or the like. For example, when the illumination area formed on the reticle R or the like is rectangular, the shape of the measurement pattern units 43A to 43C may be rectangular.

  Next, an embodiment of a microdevice manufacturing method using the device manufacturing method by the exposure apparatus 11 of the embodiment of the present invention in the lithography process will be described. FIG. 14 is a flowchart showing a manufacturing example of a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, or the like).

  First, in step S101 (design step), function / performance design (for example, circuit design of a semiconductor device) of a micro device is performed, and pattern design for realizing the function is performed. Subsequently, in step S102 (mask manufacturing step), a mask (reticle R or the like) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S103 (substrate manufacturing step), a substrate (a wafer W when a silicon material is used) is manufactured using a material such as silicon, glass, or ceramics.

  Next, in step S104 (substrate processing step), using the mask and substrate prepared in steps S101 to S104, an actual circuit or the like is formed on the substrate by lithography or the like, as will be described later. Next, in step S105 (device assembly step), device assembly is performed using the substrate processed in step S104. Step S105 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary. Finally, in step S106 (inspection step), inspections such as an operation confirmation test and a durability test of the microdevice manufactured in step S105 are performed. After these steps, the microdevice is completed and shipped.

FIG. 15 is a diagram illustrating an example of a detailed process of step S104 in the case of a semiconductor device.
In step S111 (oxidation step), the surface of the substrate is oxidized. In step S112 (CVD step), an insulating film is formed on the substrate surface. In step S113 (electrode formation step), an electrode is formed on the substrate by vapor deposition. In step S114 (ion implantation step), ions are implanted into the substrate. Each of the above steps S111 to S114 constitutes a pretreatment process at each stage of the substrate processing, and is selected and executed according to a necessary process at each stage.

  When the above-mentioned pretreatment process is completed in each stage of the substrate process, the posttreatment process is executed as follows. In this post-processing process, first, in step S115 (resist formation step), a photosensitive material is applied to the substrate. In step S116 (exposure step), the circuit pattern of the mask is transferred to the substrate by the lithography system (exposure apparatus 11) described above. Next, in step S117 (development step), the substrate exposed in step S116 is developed to form a mask layer made of a circuit pattern on the surface of the substrate. Subsequently, in step S118 (etching step), the exposed member other than the portion where the resist remains is removed by etching. In step S119 (resist removal step), the photosensitive material that has become unnecessary after the etching is removed. That is, in step S118 and step S119, the surface of the substrate is processed through the mask layer. By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the substrate.

  DESCRIPTION OF SYMBOLS 11 ... Exposure apparatus, 15 ... Illumination optical system, 16 ... Reticle stage as a mask holding apparatus, 17 ... Projection optical system, 23, 23A-23E ... Optical member for measurement, 25 ... Slit apparatus as adjustment apparatus, 36 ... Light-shielding Movable blades as a part, 37 ... actuator, 41 ... reflective layer, 42 ... absorbing layer, 43A to 43C ... pattern unit for measurement, 44 ... pattern formation region, 45, 45a-45c ... pattern non-formation region, 46 ... for measurement Pattern, 47A ... 1st part, 47B ... 2nd part, 50 ... Control apparatus (estimation apparatus, selection apparatus) which comprises a measuring device, 60 ... Shielding part, 61 ... Drive part, 70A ... 1st area | region, 70B ... 1st 2 regions, EL ... exposure light as a radiation beam, R ... reticle as a mask, SE3 ... measurement sensor used for aerial image measurement constituting the measurement apparatus, W ... Wafer as a plate.

Claims (20)

A plurality of measurement pattern units having a pattern formation region in which a measurement pattern is formed and a pattern non-formation region arranged at a position different from the pattern formation region;
The measurement optical member, wherein the pattern non-formation region is formed under different formation conditions for each of the measurement pattern units. The pattern non-formation region is formed so that a ratio of a first portion that reflects an incident radiation beam and a second portion that absorbs or diffuses the radiation beam is different for each measurement pattern unit. The optical member for measurement according to claim 1. The plurality of measurement pattern units are respectively formed in portions where an absorption layer that absorbs a radiation beam is laminated on a reflection layer that reflects the radiation beam.
2. The measurement optical member according to claim 1, wherein the pattern non-formation region is formed so that the thickness of the absorption layer is different for each measurement pattern unit. A measurement pattern unit having a pattern formation region in which a measurement pattern is formed and a pattern non-formation region arranged at a position different from the pattern formation region;
A shielding part capable of shielding a radiation beam incident on the non-patterned region;
An optical member for measurement, comprising: a drive unit that drives to move the shielding unit. A first region in which a predetermined pattern is formed;
A plurality of measurement pattern units having a pattern formation region arranged at a position different from the first region and having a measurement pattern formed thereon and a pattern non-formation region arranged at a position different from the pattern formation region are formed. A second region,
The mask in which the pattern non-formation region is formed under different formation conditions for each of the measurement pattern units. The pattern non-formation region is formed so that a ratio of a first portion that reflects an incident radiation beam and a second portion that absorbs or diffuses the radiation beam is different for each measurement pattern unit. The mask according to claim 5, wherein the mask is characterized. The second region is configured by laminating an absorption layer that absorbs a radiation beam on a reflection layer that reflects the radiation beam,
The mask according to claim 5, wherein the pattern non-formation region is formed such that the thickness of the absorption layer is different for each measurement pattern unit. In an exposure apparatus that projects an image of a pattern formed by illuminating a mask on which a predetermined pattern is formed with a radiation beam emitted from an illumination optical system onto a substrate via a projection optical system,
An optical member for measurement according to any one of claims 1 to 3,
When any one of the plurality of measurement pattern units is arranged in the optical path of the radiation beam, a radiation beam emitted from the any one measurement pattern unit to the projection optical system side is used. An exposure apparatus, comprising: In an exposure apparatus that projects an image of a pattern formed by illuminating a mask on which a predetermined pattern is formed with a radiation beam emitted from an illumination optical system onto a substrate via a projection optical system,
An optical member for measurement according to claim 4,
A measurement device for measuring using a radiation beam emitted from the measurement pattern unit to the projection optical system side when the measurement pattern unit is disposed in an optical path of the radiation beam;
An exposure apparatus comprising: a control device that controls the driving unit of the optical member for measurement. An estimation device for estimating the amount of radiation beam incident on the projection optical system;
The controller is
When the measurement device performs measurement using the measurement optical member,
The exposure apparatus according to claim 9, wherein the drive unit is controlled based on an estimation result obtained by the estimation apparatus in a state before measurement by the measurement apparatus is started. In an exposure apparatus that projects an image of a pattern formed by illuminating a mask on which a predetermined pattern is formed with a radiation beam emitted from an illumination optical system onto a substrate via a projection optical system,
A mask holding device that holds the mask according to any one of claims 5 to 7,
When any one of the plurality of measurement pattern units is disposed in the optical path of the radiation beam, the radiation beam emitted from the one measurement pattern unit to the projection optical system side is An exposure apparatus comprising: a measuring apparatus that uses and measures. In an exposure apparatus that projects an image of a pattern formed by illuminating a mask on which a predetermined pattern is formed with a radiation beam emitted from an illumination optical system onto a substrate via a projection optical system,
A plurality of measurement optical members on which a measurement pattern unit having a measurement pattern is formed;
When any one of the plurality of measurement optical members is disposed in the optical path of the radiation beam, the measurement pattern unit of any one of the measurement optical members is moved to the projection optical system side. A measuring device for measuring using the emitted radiation beam,
The plurality of measurement pattern units each have a pattern formation region where a measurement pattern is formed and a pattern non-formation region arranged at a position different from the pattern formation region,
The exposure apparatus according to claim 1, wherein the pattern non-formation region is formed under different formation conditions for each of the measurement pattern units. An estimation device for estimating the amount of radiation beam incident on the projection optical system;
9. The apparatus according to claim 8, further comprising: a selection device that selects a measurement pattern unit to be arranged in an optical path of a radiation beam from the plurality of measurement pattern units based on an estimation result by the estimation device. The exposure apparatus according to any one of Items 11 and 12. In an exposure apparatus that projects an image of a pattern formed by illuminating a mask on which a predetermined pattern is formed with a radiation beam emitted from an illumination optical system onto a substrate via a projection optical system,
A measurement optical member on which a measurement pattern unit having a pattern formation region in which a measurement pattern is formed and a pattern non-formation region disposed at a position different from the pattern formation region;
An adjusting device for adjusting the light intensity distribution of the radiation beam that illuminates the pattern non-formation region of the measurement optical member disposed in the optical path of the radiation beam;
And a measurement device that performs measurement using the radiation beam emitted from the measurement pattern unit to the projection optical system side when the measurement pattern unit is disposed in the optical path of the radiation beam. Exposure device. An estimation device for estimating the amount of radiation beam incident on the projection optical system;
The exposure apparatus according to claim 14, further comprising a control device that controls the adjustment device based on a result of estimation by the estimation device. The adjustment device includes a light shielding unit capable of shielding a part of the radiation beam emitted from the illumination optical system, and an actuator for moving the light shielding unit in a direction crossing an optical path of the radiation beam. The exposure apparatus according to claim 14 or 15. An exposure that exposes the substrate by illuminating the mask on which the predetermined pattern is formed with a radiation beam emitted from an illumination optical system, and guiding the radiation beam through the mask to the substrate through the projection optical system. In the method
A measurement pattern unit having a measurement pattern is arranged in the optical path of the radiation beam emitted from the illumination optical system, and measurement is performed using the radiation beam emitted from the measurement pattern unit to the projection optical system side. in case of,
Estimating the amount of radiation beam incident on the projection optical system in a state before measurement using the measurement pattern unit,
A radiation beam having a light quantity based on the estimation result is incident on the projection optical system via the measurement pattern unit,
An exposure method, wherein measurement is performed using a radiation beam incident on the projection optical system. When measurement is performed using any one measurement pattern unit among a plurality of measurement pattern units having different emission rates, which are ratios of the emission amount of the radiation beam toward the projection optical system with respect to the incident amount of the radiation beam In
Of the plurality of measurement pattern units, the measurement pattern unit having the emission rate corresponding to the incident amount of the radiation beam to the projection optical system in the previous state is disposed in the optical path of the radiation beam. The exposure method according to claim 17, characterized in that: When performing measurement using the measurement pattern unit,
18. The exposure method according to claim 17, wherein a light intensity distribution of the radiation beam incident on the measurement pattern unit is adjusted based on an incident amount of the radiation beam to the projection optical system in a previous state. . In a device manufacturing method including a lithography process,
17. The device manufacturing method using the exposure apparatus according to claim 8 in the lithography process.

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