Exposure apparatus

Abstract

To provide an exposure apparatus capable of executing focus control with high accuracy efficiently.SOLUTION: In an exposure apparatus, a detection member on which a detection pattern for focus detection is formed is held on an optical path of exposure light from a light emitting part to a projection optical system, in a step of detecting a focus position of a projection optical system. The detection pattern has a pattern which has a first end part and a second end part opposing to each other, and light transmission region is formed continuously from the first end part to the second end part such that their opposite directions become a long axis direction. As the position changes along the long axis direction from the first end part toward the second end part of the pattern formed on the detection member, an optical path length of exposure light from the light transmission region to the projection optical system is continuously changed by an optical path adjusting part. An image of the a detection pattern of the detection member held by a holding part is captured by an imaging part. Focus control is executed on the basis of an image of a captured detection pattern.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an exposure apparatus including a projection optical system. [Background technology]

[0002] Exposure apparatuses are used in the process of manufacturing patterns for semiconductor elements, printed circuit boards, liquid crystal substrates, etc. by photolithography. The exposure apparatus irradiates a mask (reticle) on which a pattern is formed with exposure light. The exposure light irradiated onto the mask is then irradiated onto a workpiece by a projection optical system, and the mask pattern is transferred (exposed) onto the workpiece.

[0003] To transfer a mask pattern onto a workpiece with high accuracy, alignment control, which aligns the mask and workpiece, and focus control, which positions the workpiece at the focus position of the projection optical system, are important.

[0004] Patent Document 1 discloses a technique for suppressing a decrease in productivity and a decrease in exposure accuracy caused by focus alignment of an exposure apparatus. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-190654 Summary of the Invention [Problem to be solved by the invention]

[0006] There is a demand for a technology that can efficiently perform focus control of an exposure apparatus with high precision.

[0007] In view of the above circumstances, an object of the present invention is to provide an exposure apparatus that is capable of efficiently executing focus control with high precision. [Means for solving the problem]

[0008] In order to achieve the above object, an exposure apparatus according to one aspect of the present invention comprises a light output unit, a mask stage, a workpiece stage, a projection optical system, a holding unit, an imaging unit, and an optical path length adjustment unit. The light emitting section emits exposure light. The mask stage holds an exposure mask. The workpiece stage holds a workpiece. The projection optical system irradiates the workpiece held on the workpiece stage with the exposure light that is emitted from the light emitting section and transmitted through the exposure mask. During the process of detecting the focus position of the projection optical system, the holding section holds a detection member on which a detection pattern for focus detection is formed, in the optical path of the exposure light from the light output section to the projection optical system. The photographing unit is positioned in the optical path of the exposure light emitted from the projection optical system during the process of detecting the focus position of the projection optical system, and photographs an image of the detection pattern of the detection member held by the holding unit. The detection pattern includes a first pattern having a first end and a second end opposite the first end in a predetermined direction, and in which a light-transmitting region is formed continuously from the first end to the second end so that the predetermined direction is the long axis direction. The optical path length adjustment unit continuously changes the optical path length of the exposure light from the light transmission region to the projection optical system as the position of the first pattern formed on the detection member held by the holding unit changes along the longitudinal axis direction from the first end toward the second end.

[0009] In this exposure apparatus, during the process of detecting the focus position of the projection optical system, a detection member is held in the optical path of the exposure light from the light emitting unit to the projection optical system. Then, the optical path length adjusting unit continuously changes the optical path length of the exposure light from the light transmitting region to the projection optical system as the position of the first pattern formed on the detection member changes along the major axis direction from the first end to the second end. This makes it possible to efficiently detect the focus position of the projection optical system with high accuracy based on the image of the detection pattern captured by the capturing unit. As a result, it becomes possible to perform focus control with high accuracy and efficiency.

[0010] The optical path length adjustment unit may continuously increase the optical path length of the exposure light from the light transmitting region to the projection optical system or continuously decrease the optical path length of the exposure light as the position changes along the major axis direction from the first end to the second end of the first pattern.

[0011] The detection member may be made of a flat plate member on which the detection pattern is formed. In this case, the holding unit may function as the optical path length adjusting unit and hold the detection member obliquely with respect to the optical axis direction such that a distance in the optical axis direction of the exposure light emitted from the light emitting unit from the light transmitting region to the projection optical system changes continuously as a position of the detection member changes from the first end to the second end of the first pattern along the long axis direction.

[0012] The detection member may be made of a flat plate member on which the detection pattern is formed. In this case, the holder may hold the detection member so as to be perpendicular to the optical axis direction of the exposure light emitted from the light emitting unit. Furthermore, the optical path length adjustment unit may include an optical member that is disposed between the detection member and the projection optical system and that continuously changes the optical path length of the exposure light from the light transmitting region to the projection optical system as the position of the optical member changes along the major axis direction from the first end toward the second end of the first pattern.

[0013] The optical member may have an incident surface through which the exposure light emitted from the light-transmitting regions of the first pattern enters, and an exit surface through which the exposure light incident on the incident surface exits toward the projection optical system. In this case, the incident surface may be planar and disposed so as to be perpendicular to the optical axis direction at a position facing the light-transmitting regions of the first pattern. The exit surface may also be planar and disposed obliquely with respect to the optical axis direction so that the distance from the incident surface in the optical axis direction continuously changes as the position of the exit surface changes along the major axis direction of the first pattern.

[0014] The optical member may be formed of a prism having a predetermined refractive index.

[0015] The detection pattern may include a first end side pattern consisting of a light-transmitting region formed based on the position of the first end of the first pattern, and a second end side pattern consisting of a light-transmitting region formed based on the position of the second end of the first pattern.

[0016] The detection pattern may include an intermediate position pattern consisting of a light-transmitting region formed based on a predetermined position along the longitudinal axis direction between the first end and the second end of the first pattern.

[0017] The first pattern may have a rectangular shape extending along the long axis direction.

[0018] The detection pattern may include a plurality of first patterns.

[0019] The detection pattern may include a second pattern having a third end and a fourth end facing each other in a direction perpendicular to the long axis direction of the first pattern, and in which a light-transmitting region is formed continuously from the third end to the fourth end so that the direction perpendicular to the long axis direction of the first pattern is the long axis direction.

[0020] The detection pattern may include a plurality of second patterns.

[0021] The detection member may be made of a flat plate member on which the detection pattern is formed. In this case, the holding unit may hold the detection member so as to be perpendicular to the optical axis direction of the exposure light emitted from the light emitting unit. Furthermore, the optical path length adjusting unit may have a first optical member and a second optical member. The first optical member is disposed between the region of the detection member where the first pattern is formed and the projection optical system, and continuously changes the optical path length of the exposure light from the light-transmitting region of the first pattern to the projection optical system as the position of the first optical member changes along the long axis direction of the first pattern from the first end toward the second end of the first pattern. The second optical member is disposed between the region of the detection member where the second pattern is formed and the projection optical system, and continuously changes the optical path length of the exposure light from the light-transmitting region of the second pattern to the projection optical system as the position of the second optical member changes along the long axis direction of the second pattern from the third end to the fourth end of the second pattern. [Effects of the Invention]

[0022] As described above, according to the present invention, it is possible to efficiently perform focus control with high accuracy. Note that the effects described here are not necessarily limited to those described herein, and may be any of the effects described in this disclosure. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram showing an example of the basic configuration of an exposure apparatus according to a first embodiment of the present invention. [Figure 2] 10A and 10B are schematic diagrams showing an example of the configuration of a detection member used in a process of detecting the focus position of the projection optical system. [Figure 3]10A and 10B are schematic diagrams showing an example of a state in which a detection member is held during a step of detecting the focus position of a projection optical system. [Figure 4] FIG. 10 is a schematic diagram showing an example of a method for holding a detection member that is different from the holding method according to the present invention (a diagram of a comparative example). [Figure 5] 5 is a schematic diagram showing an image of the detection pattern photographed by the detection pattern photographing unit in the comparative example shown in FIG. 4. FIG. [Figure 6] 4 is a schematic diagram showing an image of a detection pattern photographed by a detection pattern photographing unit in the configuration example according to the present invention shown in FIG. 3. FIG. [Figure 7] 4 is a schematic diagram showing an image of a detection pattern photographed by a detection pattern photographing unit in the configuration example according to the present invention shown in FIG. 3. FIG. [Figure 8] FIG. 10 is a schematic diagram showing an example of the configuration during the step of detecting the focus position of the projection optical system 3 according to the second embodiment of the present invention. [Figure 9] FIG. 2 is a schematic diagram showing an example of the configuration of a prism (side view). [Figure 10] FIG. 2 is a bottom view (side view) showing an example of the configuration of a prism. [Figure 11] 10A and 10B are schematic diagrams showing other examples of detection patterns formed on the detection member. [Figure 12] 10A and 10B are schematic diagrams showing other examples of detection patterns formed on the detection member. [Figure 13] 10A and 10B are schematic diagrams showing other examples of detection patterns formed on the detection member. [Figure 14] 10A and 10B are schematic diagrams showing other examples of detection patterns formed on the detection member. [Figure 15] 10A and 10B are schematic diagrams showing other examples of detection patterns formed on the detection member. [Figure 16] 10 is a schematic diagram showing a configuration example of a detection member (detection pattern) according to a third embodiment of the present invention. FIG. [Figure 17] 3A and 3B are schematic diagrams showing configuration examples of a first prism and a second prism. [Figure 18]3A and 3B are schematic diagrams showing configuration examples of a first prism and a second prism. [Figure 19] 3A and 3B are schematic diagrams showing configuration examples of a first prism and a second prism. [Figure 20] 3A and 3B are schematic diagrams showing configuration examples of a first prism and a second prism. [Figure 21] 10A and 10B are schematic diagrams showing other configuration examples of the detection member (detection pattern). DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] First Embodiment [Configuration of exposure equipment] 1 is a schematic diagram showing an example of the basic configuration of an exposure apparatus according to a first embodiment of the present invention. The exposure apparatus 1 has a light output unit 2, a mask stage MS, a workpiece stage WS, a projection optical system 3, a mask stage movement mechanism 5, a workpiece stage movement mechanism 6, a projection optical system adjustment mechanism 7, a detection member holder 8, an optical path length adjustment unit 9, a detection pattern photographing unit 10, and a control device 11.

[0026] Hereinafter, as shown in FIG. 1, the optical axis direction of the light output unit 2 (the output direction of the exposure light EL) is defined as the Z direction, with the positive side of the Z axis defined as the upper side and the negative side defined as the lower side. Furthermore, the direction perpendicular to the Z direction and extending left and right in the drawing is defined as the X direction, with the positive side of the X axis defined as the right side and the negative side defined as the left side. Furthermore, the depth direction perpendicular to both the Z direction and the X direction and perpendicular to the paper surface is defined as the Y direction, with the positive side of the Y axis defined as the back side and the negative side defined as the front side. Of course, the application of this technology is not limited to the orientation in which the exposure apparatus 1 is disposed.

[0027] The light emitting unit 2 emits the exposure light EL downward. For example, a short arc type mercury lamp is used as the light emitting unit 2. The mercury lamp emits ultraviolet light having wavelengths of, for example, 365 nm (i-line), 405 nm (h-line), 436 nm (g-line), etc. Of course, the configuration is not limited to this, and a lamp that emits light in a wavelength band other than ultraviolet light may also be used. Alternatively, a solid-state light source such as an LED (Light Emitting Diode) or an LD (Laser Diode) may be used.

[0028] The mask stage MS is disposed below the light emitting section 2. The mask stage MS holds an exposure mask (hereinafter simply referred to as a mask) M. In this embodiment, the mask M is disposed so as to be perpendicular to the optical axis direction (Z direction) of the light emitting section 2. A predetermined mask pattern and alignment marks (mask marks) are formed on the mask M. The mask marks are also called mask alignment marks.

[0029] The projection optical system 3 irradiates the exposure light EL emitted from the light emitting unit 2 and transmitted through the mask M onto the workpiece W held on the workpiece stage WS. As a result, an image of the mask pattern formed on the mask M is projected onto the workpiece W. The projection optical system 3 is configured as an imaging optical system having a projection lens. The detailed configuration of the projection optical system 3 is not limited, and any configuration may be adopted.

[0030] The workpiece stage WS holds the workpiece W. In this embodiment, the workpiece W is placed so as to be perpendicular to the optical axis direction (Z direction) of the light emitting part 2.

[0031] The workpiece stage WS has a mounting surface 12 on which the workpiece W is placed. A plurality of vacuum suction holes are formed in the mounting surface 12, and the workpiece W is held by vacuum suction. Note that the specific configuration and method for holding the workpiece W are not limited and may be designed as desired.

[0032] The mask stage movement mechanism 5 linearly moves (translates) the mask stage MS in each of the left-right direction (X direction), depth direction (Y direction), and optical axis direction (Z direction). The mask stage movement mechanism 5 also rotates the mask stage MS around the optical axis direction (Z direction) as the rotation axis direction. The mask stage movement mechanism 5 also tilts (inclines) the mask stage MS with respect to the optical axis direction (Z direction) of the light output unit 2.

[0033] The workpiece stage moving mechanism 6 linearly moves the workpiece stage WS in each of the left-right direction (X direction), depth direction (Y direction), and optical axis direction (Z direction). The workpiece stage moving mechanism 6 also rotates the workpiece stage WS around the optical axis direction (Z direction) as the rotation axis direction. The workpiece stage moving mechanism 6 also tilts the workpiece stage WS with respect to the optical axis direction (Z direction) of the light output unit 2.

[0034] By driving the mask stage moving mechanism 5 and the workpiece stage moving mechanism 6, the relative position of the workpiece W with respect to the mask M can be changed.

[0035] The specific configurations of the mask stage moving mechanism 5 and the workpiece stage moving mechanism 6 are not limited, and any moving mechanism such as a linear stage using a stepping motor or the like, or any rotating mechanism using a gear mechanism or the like may be used.

[0036] Furthermore, the mask stage moving mechanism 5 and the workpiece stage moving mechanism 6 can be configured in any manner that allows the relative positional relationship of the workpiece stage WS with respect to the mask stage MS to be changed.

[0037] For example, only the mask stage moving mechanism 5 may be provided, and only the mask stage MS may be movable. Alternatively, only the workpiece stage moving mechanism 6 may be provided, and only the workpiece stage WS may be movable. Furthermore, the mask stage MS is moved by the mask stage moving mechanism 5 for movement in the left-right direction (X direction), depth direction (Y direction), and optical axis direction (Z direction). The workpiece stage WS is moved by the workpiece stage moving mechanism 6 for rotation about the optical axis direction (Z direction) as the rotation axis direction and tilt (incline) relative to the optical axis direction (Z direction). Such a configuration can also be adopted.

[0038] Alignment marks (workpiece marks) are formed on the workpiece W. The workpiece marks are also called workpiece alignment marks.

[0039] In order to align the mask M with the workpiece W in the rotational directions with the left-right direction (X direction), depth direction (Y direction), and optical axis direction (Z direction) as the rotation axis direction, it is desirable to form three or more mask marks on the mask M. The same number of workpiece marks are formed on the workpiece W corresponding to the three or more mask marks.

[0040] The corresponding mask marks and workpiece marks are formed to have a predetermined positional relationship when the mask M and workpiece W have a desired positional relationship when viewed from the optical axis direction (Z direction). In other words, the mask marks and workpiece marks are formed so that when the exposure light EL is irradiated onto the mask marks from the light output unit 2, the image of the mask mark projected by the projection optical system 3 has a predetermined positional relationship with the workpiece mark. Any positional relationship may be adopted as the predetermined positional relationship.

[0041] The projection optical system adjustment mechanism 7 adjusts the projection optical system 3. For example, the projection optical system adjustment mechanism 7 is driven to adjust the focus position, adjust the imaging magnification, correct distortion, etc. For example, the projection optical system 3 can be adjusted by adjusting, processing, replacing, etc. the position of optical elements such as the projection lens included in the projection optical system 3. The specific configuration of the projection optical system adjustment mechanism 7 is not limited, and any configuration may be adopted.

[0042] The detection member holding unit 8, the optical path length adjusting unit 9, and the detection pattern photographing unit 10 are blocks that operate during the process of detecting the focus position of the projection optical system 3, and will be described in detail later.

[0043] The control device 11 controls the operation of each block of the exposure apparatus 1. The control device 11 has hardware necessary for a computer, such as processors such as a CPU, GPU, and DSP, memories such as ROM and RAM, and storage devices such as HDDs. In this embodiment, the storage unit 13 is configured by a storage device such as a non-volatile memory. Any computer-readable, non-transitory storage medium may be used to realize the storage unit 13.

[0044] The processor of the control device 11 loads the program according to the present technology stored in the storage unit 13 or memory into RAM and executes it, thereby executing an exposure method including an alignment method and a focus control method according to the present technology. Note that the focus control method includes a method for detecting the focus position of the projection optical system 3.

[0045] The control device 11 can be realized by any computer such as a PC (Personal Computer), etc. Of course, hardware such as a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) may also be used.

[0046] In this embodiment, the processor of the control device 11 executes a program according to the present technology, thereby realizing an alignment control unit 14 and a focus control unit 15 as functional blocks.

[0047] The alignment control unit 14 aligns the mask M and the workpiece W. In this embodiment, the mask M held on the mask stage MS is irradiated with exposure light EL, and a mask mark is projected onto the workpiece stage WS by the projection optical system 3. An image of the projected mask mark is captured by an alignment camera (not shown).

[0048] Next, the workpiece W is held on the workpiece stage WS with the emission of the exposure light EL from the light emission unit 2 stopped. Then, the workpiece marks formed on the workpiece W are photographed by an alignment camera. When the images of the mask marks and the workpiece marks are photographed, the alignment control unit 14 moves the alignment camera to a predetermined position.

[0049] The alignment control unit 14 detects the positions of the mask mark and the workpiece mark based on the images of the mask mark and the images of the workpiece mark taken by the alignment camera.

[0050] Furthermore, the alignment control unit 14 controls the mask stage moving mechanism 5 and the workpiece stage moving mechanism 6 based on the detected positions of the mask marks and the workpiece marks, and aligns the mask M and the workpiece W so that they have a desired positional relationship. Specifically, the mask stage moving mechanism 5 and the workpiece stage moving mechanism 6 are controlled so that the mask marks and the workpiece marks have a predetermined positional relationship. In this way, the mask M and the workpiece W are aligned.

[0051] The focus control unit 15 controls the focus of the mask pattern projected (imaged) onto the workpiece W. Specifically, the focus control unit 15 controls the projection optical system adjustment mechanism 7, the mask stage moving mechanism 5, and the workpiece stage moving mechanism 6 so that the workpiece W is positioned at the focus position of the projection optical system 3.

[0052] In this embodiment, focus control involves a step of detecting the focus position of the projection optical system 3. Also, focus control involves a step of adjusting the focus position of the projection optical system 3 by driving the projection optical system adjustment mechanism 7. For example, the focus position is adjusted after the focus position of the projection optical system 3 is detected. Alternatively, the focus position detection step may be performed again after the focus position is adjusted.

[0053] Furthermore, as focus control, a process is executed in which the relative positional relationship between the mask stage MS and the workpiece stage WS in the optical axis direction (Z direction) is adjusted by driving the mask stage moving mechanism 5 and the workpiece stage moving mechanism 6. Of course, the control is not limited to this.

[0054] In addition, functional blocks that perform various controls related to exposure are configured in the control device 11, but are not shown in the figure. In addition, dedicated hardware such as an IC (integrated circuit) may be used as appropriate to realize each functional block.

[0055] Once the alignment of the mask M and the workpiece W and focus control are complete, the exposure process for the workpiece W begins, and the exposure light EL is emitted from the light emitting unit 2. The exposure light EL emitted from the light emitting unit 2 is irradiated onto the workpiece W, which is coated with resist, via the mask M, on which a mask pattern is formed, and the projection optical system 3. As a result, the mask pattern is projected onto the workpiece W and exposed.

[0056] [Process for detecting the focus position of the projection optical system] The process of detecting the focus position of the projection optical system 3 will be described with reference to FIGS.

[0057] Fig. 2 is a schematic diagram showing an example of the configuration of a detection member 17 used in the process of detecting the focus position of the projection optical system 3. Fig. 3 is a schematic diagram showing an example of a state in which the detection member 17 is held in the process of detecting the focus position of the projection optical system 3.

[0058] 1 operate during the process of detecting the focus position of the projection optical system 3. Note that in FIG. 3, the detection member holding unit 8, the optical path length adjusting unit 9, and the detection pattern photographing unit 10 are indicated using the same reference numerals.

[0059] During the process of detecting the focus position of the projection optical system 3, the detection member holding unit 8 holds a detection member 17, on which a detection pattern DP for focus detection is formed, in the optical path of the exposure light EL from the light output unit 2 to the projection optical system 3. In this embodiment, the detection member 17 is made of a flat plate member on which the detection pattern DP is formed. The detection member holding unit 8 corresponds to one embodiment of a holder according to the present invention.

[0060] As shown in FIG. 2, the detection pattern DP includes a first pattern 21 having a first end 18 and a second end 19 opposite the first end 18 in a predetermined direction, and in which a light-transmitting region 20 is formed continuously from the first end 18 to the second end 19 so that the predetermined direction is the long axis direction.

[0061] In this embodiment, the detection pattern DP is composed of one first pattern 21. The first pattern 21 is rectangular, extends along the long axis direction, and has two long sides that face each other in the short axis direction. The first pattern 21 also extends along the short axis direction and has two short sides that face each other in the long axis direction.

[0062] In this embodiment, the two short sides are the first end 18 and the second end 19. The present invention can be applied without limiting which of the two short sides is the first end 18 (second end 19). In this embodiment, the left short side in FIG. 2 will be described as the first end 18, and the right short side as the second end 19.

[0063] The light-transmitting region 20 is typically configured as an opening that penetrates the detection member 17. However, the present invention is not limited to this, and the opening may be filled with a light-transmitting material.

[0064] The optical path length adjustment unit 9 continuously changes the optical path length of the exposure light EL from the light transmission region 20 to the projection optical system 3 as the position of the first pattern 21 formed on the detection member 17 held by the detection member holding unit 8 changes along the long axis direction from the first end 18 to the second end 19. The optical path length adjustment unit 9 corresponds to one embodiment of the optical path length adjustment unit according to the present invention.

[0065] Specifically, the optical path length adjustment unit 9 continuously increases or decreases the optical path length of the exposure light EL from the light transmission region 20 to the projection optical system 3 as the position changes along the longitudinal axis direction from the first end 18 to the second end 19 of the first pattern 21.

[0066] 3 illustrates a state in which detection member 17 is held by detection member holding portion 8. When detection member 17 held by detection member holding portion 8 is viewed from above along the optical axis direction (Z direction), detection member 17 is held so that the long axis direction of first pattern 21 is parallel to the left-right direction (X direction).

[0067] Detecting member 17 is held so that first end 18 of first pattern 21 is located on the left side and second end 19 is located on the right side. Furthermore, as shown in Fig. 3, detecting member 17 is held obliquely with respect to the optical axis direction (Z direction) so that second end 19 of first pattern 21 is located above first end 18 in the optical axis direction (Z direction).

[0068] That is, in this embodiment, the detection member holding portion 8 holds the detection member 17 at an angle to the optical axis direction (Z direction) so that as the position changes along the longitudinal axis direction from the first end 18 to the second end 19 of the first pattern 21, the distance in the optical axis direction (Z direction) of the exposure light emitted from the light emitting portion 2 from the light transmitting region 20 to the projection optical system 3 changes continuously.

[0069] This makes it possible to continuously increase the optical path length of the exposure light EL from the light transmitting region 20 to the projection optical system 3 at each position from the first end 18 to the second end 19.

[0070] In this manner, in this embodiment, the detection member holding unit 8 also functions as the optical path length adjusting unit 9. The detection member holding unit 8 holds the detection member 17 at an angle with respect to the optical axis direction (Z direction), so that the optical path length of the exposure light EL from the light transmitting region 20 to the projection optical system 3 is continuously increased at each position from the first end 18 to the second end 19.

[0071] The detection pattern photographing unit 10 is disposed in the optical path of the exposure light EL emitted from the projection optical system 3 during the process of detecting the focus position of the projection optical system 3, and photographs an image of the detection pattern DP of the detection member 17 held by the detection member holding unit 8. The detection pattern photographing unit 10 corresponds to one embodiment of the photographing unit according to the present invention.

[0072] An imaging device capable of capturing two-dimensional images is typically used as the detection pattern capturing unit 10. For example, a digital camera equipped with an image sensor such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal-Oxide Semiconductor) sensor can be used.

[0073] 3 schematically illustrates the position of the image sensor of the detection pattern photographing unit 10. As shown in Fig. 3, the detection pattern photographing unit 10 is disposed at a position where it can photograph the image of the detection pattern DP projected by the projection optical system 3, with the image sensor being perpendicular to the optical axis direction (Z direction).

[0074] For example, during the process of detecting the focus position of the projection optical system 3, the mask stage MS and workpiece stage WS are moved to positions out of the optical path of the exposure light EL by driving the mask stage moving mechanism 5 and the workpiece stage moving mechanism 6. Then, a detection member holding unit 8 (optical path length adjusting unit 9) that holds a detection member 17 shown in FIG. 3, and a detection pattern photographing unit 10 are placed in the optical path of the exposure light EL.

[0075] Alternatively, the mask stage MS may function as the detection member holding unit 8. The detection member 17 may be disposed at an angle to the optical axis direction (Z direction) by the mask stage MS. Alternatively, a portion for holding the detection member 17 may be configured in a part of the mask stage MS that is different from the part that holds the mask M. Then, during the step of detecting the focus position of the projection optical system 3, the mask stage MS may be moved, and the detection member 17 may be disposed in the optical path of the exposure light EL.

[0076] Furthermore, a detection pattern photographing unit 10 may be installed at a predetermined position on the workpiece stage WS. Then, during the process of detecting the focus position of the projection optical system 3, the workpiece stage WS may be moved and the detection pattern photographing unit 10 may be positioned in the optical path of the exposure light EL. Any other configuration may be adopted.

[0077] Fig. 4 is a schematic diagram showing an example of a method for holding the detection member 17 that is different from the holding method according to the present invention. Fig. 4 is a diagram created to facilitate understanding of the present invention, and hereinafter the example shown in Fig. 4 may be referred to as a comparative example.

[0078] 4, the detection member 17 is held so as to be perpendicular to the optical axis direction (Z direction). That is, the detection member 17 is held so that the first end 18 and the second end 19 of the first pattern 21 are at the same position in the optical axis direction (Z direction).

[0079] 4, the detection pattern photographing unit 10 is disposed so that the image sensor of the detection pattern photographing unit 10 is disposed at the focus position of the projection optical system 3. That is, in the comparative example shown in FIG. 4, the rectangular first pattern 21 and the image sensor of the detection pattern photographing unit 10 are in a conjugate positional relationship via the projection optical system 3.

[0080] Fig. 5 is a schematic diagram showing an image 23 of the detection pattern DP captured by the detection pattern capturing unit 10 in the comparative example shown in Fig. 4. In Fig. 5, the captured first pattern 21 is shown in black.

[0081] 4, the first pattern 21 of the detection member 17 and the image sensor of the detection pattern photographing unit 10 are in a conjugate positional relationship via the projection optical system 3. Therefore, the light transmitting region 20 of the first pattern 21 is photographed as a well-focused, blur-free image.

[0082] 6 and 7 are schematic diagrams showing images 23 of the detection pattern DP captured by the detection pattern capturing unit 10 in the configuration example according to the present invention shown in Fig. 3. In the configuration shown in Fig. 3, the detection member 17 is disposed obliquely with respect to the optical axis direction (Z direction). That is, the first pattern 21 is disposed so that its position in the optical axis direction (Z direction) continuously changes from the first end 18 to the second end 19.

[0083] This causes the optical path length of the exposure light EL from the light-transmitting region 20 to the projection optical system 3 to increase continuously at each position from the first end 18 to the second end 19 of the first pattern 21. As a result, the images of the light-transmitting region 20 at each position from the first end 18 to the second end 19 of the first pattern 21 are formed at different positions in the optical axis direction (Z direction) by the projection optical system 3.

[0084] At each position from the first end 18 to the second end 19 of the first pattern 21, at the position where the image sensor of the detection pattern photographing unit 10 is positioned at the position where the light-transmitting region 20 is imaged, the image of the light-transmitting region 20 is photographed as a well-focused, blur-free image.

[0085] On the other hand, at each position from the first end 18 to the second end 19 of the first pattern 21, at positions where the position where the light-transmitting region 20 is imaged is misaligned with the position of the image sensor of the detection pattern photographing unit 10, the image of the light-transmitting region 20 is photographed as an out-of-focus, blurred image.

[0086] At each position from the first end 18 to the second end 19 of the first pattern 21, the greater the deviation between the position where the light-transmitting region 20 is imaged and the position of the image sensor of the detection pattern photographing unit 10, the greater the amount of blurring of the image of the light-transmitting region 20.

[0087] In other words, at each position from the first end 18 to the second end 19 of the first pattern 21 that is conjugate with the image sensor of the detection pattern photographing unit 10 via the projection optical system 3, the image of the light-transmitting region 20 is photographed as a well-focused, blur-free image.

[0088] On the other hand, at each position from the first end 18 to the second end 19 of the first pattern 21 that is not in a conjugate positional relationship with the image sensor of the detection pattern photographing unit 10 via the projection optical system 3, the image of the light-transmitting region 20 is photographed as an out-of-focus, blurred image.

[0089] At each position from the first end 18 to the second end 19 of the first pattern 21, the greater the deviation from the position conjugate with the image sensor of the detection pattern photographing unit 10, the greater the amount of blurring of the image of the light-transmitting area 20.

[0090] 6, the image captured is the most focused and blur-free image at the center in the long axis direction (coincident with the X direction) of the first pattern 21 of the detection member 17. The amount of blur in the image increases as the image moves away from the focused portion to the left and right.

[0091] In the example shown in Fig. 7, the image of the portion slightly shifted to the left from the center in the long axis direction (coincident with the X direction) of the first pattern 21 of the detection member 17 is captured as the most focused and blur-free image. The amount of blur in the image increases as the image moves further to the left or right from the focused portion. Note that in Figs. 6 and 7, the images of the blurred portions are shown schematically.

[0092] In this way, in the configuration example of the present invention shown in Figure 3, it is possible to obtain the image 23 of the detection pattern DP captured by the detection pattern capturing unit 10 as an image containing information about the focus position of the projection optical system 3.

[0093] The image 23 of the detection pattern DP is output to the focus control unit 15. Then, the focus control unit 15 detects the focus position of the projection optical system 3 and executes focus control.

[0094] For example, a process for adjusting the focus position of the projection optical system 3 is performed by driving the projection optical system adjustment mechanism 7 based on the detected focus position. Also, a process for adjusting the relative positional relationship between the mask stage MS and the workpiece stage WS in the optical axis direction (Z direction) is performed by driving the mask stage movement mechanism 5 and the workpiece stage movement mechanism 6. Focus control makes it possible to transfer the mask pattern onto the workpiece W with high precision.

[0095] [Example of focus control based on an image of the detection pattern] For example, when the configuration of the comparative example shown in Figure 4 is realized by calibration or the like, the holding position of the detection member 17 in the optical axis direction (Z direction), the adjustment parameters of the projection optical system 3, and the position of the detection pattern shooting unit 10 are acquired and stored as reference information.

[0096] For example, the reference information for the holding position of the detection member 17 is the same as the reference information for the holding position of the mask M when the exposure process is performed. The reference information for the adjustment parameters of the projection optical system 3 is the same as the reference information for the adjustment parameters of the projection optical system 3 when the exposure process is performed. The reference information for the position of the detection pattern photographing unit 10 is the focus position of the projection optical system 3 when the adjustment parameters are set to the reference information.

[0097] 3, the detection member 17 is held at an angle so that the center portion of the first pattern 21 of the detection member 17 coincides with the reference information for the holding position of the detection member 17. The adjustment parameters of the projection optical system 3 and the position of the detection pattern photographing unit 10 are set to the reference information when the comparative example shown in FIG.

[0098] In the process of detecting the focus position of the projection optical system 3, the focus control unit 15 analyzes the image 23 of the detection pattern DP and detects the pixel that is most in focus. For example, the most in-focus area in the image 23 of the detection pattern DP is detected, and the pixel at the center of that area is detected as the pixel that is most in focus. However, this is not limiting, and any analysis technique may be used to detect the pixel that is most in focus.

[0099] For example, in the area where the first pattern 21 is photographed, frequency analysis, differentiation processing, etc. are performed on the pixel values (brightness values) of a plurality of pixels aligned along the long axis direction of the first pattern 21. For example, the pixel showing the highest peak value is detected as the pixel that is best in focus. Of course, other image analysis methods, etc. may also be employed.

[0100] To detect the pixel with the best focus, any image analysis technique may be used, such as image size conversion, shape recognition, matching using a model image of an object, edge detection, or projective transformation. Furthermore, any machine learning algorithm may be used, such as a deep neural network (DNN), a recurrent neural network (RNN), or a convolutional neural network (CNN). The application of the machine learning algorithm may be performed on any process within the present disclosure.

[0101] For example, let us assume that the focus position of the projection optical system 3 is in an ideal state, with no errors occurring due to aging, the effects of heat, or the like. In this case, in the image 23 of the detection pattern DP captured by the detection pattern capturing unit 10, the central portion of the first pattern 21 is captured as the most focused, blur-free image. In other words, the pixel at which the central portion of the first pattern 21 is captured is detected as the most focused pixel.

[0102] If the focus position of the projection optical system 3 deviates from the ideal state, the detected most focused pixel will deviate from the pixel at which the central portion of the first pattern 21 is captured. Therefore, it is possible to detect the deviation of the focus position of the projection optical system 3 from the ideal state based on the difference between the position of the detected most focused pixel and the position of the pixel at which the central portion of the first pattern 21 is captured. In other words, it is possible to calculate the amount of deviation of the focus position of the projection optical system 3 as position information in the optical axis direction (Z direction).

[0103] For example, the correlation between the difference between the position of the pixel that is detected as being most in focus by calibration or the like and the position of the pixel where the central part of the first pattern 21 is photographed, and the amount of deviation of the focus position of the projection optical system 3 may be stored in table information or the like. Then, the amount of deviation of the focus position of the projection optical system 3 may be detected by referring to the table information or the like.

[0104] Alternatively, the amount of deviation in the focus position of the projection optical system 3 may be calculated based on the difference between the position of the detected pixel that is most in focus and the position of the pixel where the central part of the first pattern 21 is photographed, the size of the pixel (pixel size), the tilt angle of the detection member 17, etc.

[0105] Of course, an image 23 of the detection pattern DP may be input to a trained model trained by a machine learning algorithm, and the trained model may output information on the amount of deviation of the focus position of the projection optical system 3, or on the focus position of the projection optical system 3 itself.

[0106] The focus control unit 15 drives the projection optical system adjustment mechanism 7, for example, so that the focus position of the projection optical system 3 is in an ideal state. Alternatively, among the positions from the first end 18 to the second end 19 of the first pattern 21, the position in the optical axis direction (Z direction) that is in a positional relationship conjugate with the image sensor of the detection pattern photographing unit 10 is stored, and the mask stage MS is moved so that the mask M is placed at that position. Then, the workpiece stage WS is moved so that the workpiece W is placed at the position of the image sensor of the detection pattern photographing unit 10.

[0107] Alternatively, any focus control may be performed so that the workpiece W is positioned at the focus position of the projection optical system 3 that projects the mask pattern irradiated with the exposure light EL. Highly accurate focus control can be performed based on information about the detected focus position of the projection optical system 3.

[0108] As described above, in the exposure apparatus 1 according to this embodiment, during the process of detecting the focus position of the projection optical system 3, the detection member 17 is held in the optical path of the exposure light EL from the light emitting unit 2 to the projection optical system 3. Then, the optical path length adjusting unit 9 continuously changes the optical path length of the exposure light EL from the light transmitting region 20 to the projection optical system 3 as the position of the first pattern 21 formed on the detection member 17 changes along the major axis direction from the first end 18 to the second end 19. This makes it possible to efficiently detect the focus position of the projection optical system 3 with high accuracy based on the image of the detection pattern DP captured by the detection pattern capturing unit 10. As a result, it becomes possible to perform focus control efficiently with high accuracy.

[0109] One possible method for focus alignment (focus calibration) of the exposure apparatus 1 is to arrange the detection member 17 so that it is perpendicular to the high axis direction, and measure the image and light amount of the detection pattern DP projected by the projection optical system 3. That is, in the configuration of the comparative example shown in Fig. 4, one possible method is to detect the focus position by observing the detection pattern DP projected by the projection optical system 3.

[0110] In this method, it is necessary to photograph and measure the detection pattern DP projected by the projection optical system 3 while moving a camera that photographs the detection pattern DP projected by the projection optical system 3 and a sensor that measures the amount of light of the detection pattern DP projected by the projection optical system 3 along the optical axis direction (Z direction). Therefore, the detection process of the projection optical system 3 takes time, which reduces productivity.

[0111] In the detection process of the projection optical system 3 according to the present invention, there is no need to move the detection pattern photographing unit 10 along the optical axis direction (Z direction), and it is possible to detect the focus position of the projection optical system 3 based on the image 23 of the detection pattern DP photographed at once by the detection pattern photographing unit 10. This makes it possible to achieve high productivity.

[0112] Furthermore, in the detection process of the projection optical system 3 according to the present invention, it is possible to detect the focus position of the projection optical system 3 with high accuracy by analyzing the image 23 of the detection pattern DP captured by the detection pattern capturing unit 10.

[0113] That is, by implementing the present invention, it is possible to provide an exposure apparatus 1 that is advantageous in terms of focus positioning (focus calibration), and it is possible to improve productivity and exposure accuracy.

[0114] It is also possible to detect the tilt of the mask stage MS or workpiece stage WS by analyzing the detection pattern DP image 23. For example, if an unintended tilt occurs in the mask stage MS or workpiece stage WS, it becomes possible to detect and correct the tilt.

[0115] In this embodiment, a rectangular pattern is used as an example of the first pattern 21 formed as the detection pattern DP. The shape and size of the first pattern 21 are not limited, and any pattern in which the light-transmitting region 20 is formed continuously from the first end 18 to the second end 19 can be used. For example, an elliptical pattern or the like may be used as the first pattern 21.

[0116] The width (size in the minor axis direction) of the first pattern 21 is not limited either, but it is also possible to set the width of the first pattern 21 based on the resolution of the projection optical system 3 (lenses that make up the projection optical system 3). For example, the width of the first pattern 21 is set to be approximately the same size as the resolution of the projection optical system 3 (lenses that make up the projection optical system 3), or slightly larger. This makes it possible to easily detect the pixel that is most in focus, and improves the detection accuracy of the focus position.

[0117] The length (size in the major axis direction) of the first pattern 21 is also not limited. For example, the first pattern 21 may be formed with a length that covers the area onto which the mask pattern is projected during the exposure process. However, without being limited thereto, the first pattern 21 may be formed with a length that is shorter than the area onto which the mask pattern is projected during the exposure process.

[0118] For example, if the range in which the focus position of the projection optical system 3 varies is specified, the first pattern 21 may be formed with a length that allows the variation in the focus position to be detected.

[0119] <Second embodiment> An exposure apparatus according to a second embodiment of the present invention will be described. In the following description, descriptions of parts that have the same configuration and action as those in the exposure apparatus 1 described in the above embodiment will be omitted or simplified.

[0120] In the first embodiment, the detection member holding portion 8 also functions as an optical path length adjustment portion 9, and by arranging the detection member 17 at an angle to the optical axis direction (Z direction), the optical path length of the exposure light EL from the light transmission region 20 to the projection optical system 3 is continuously increased at each position from the first end 18 to the second end 19 of the first pattern 21.

[0121] FIG. 8 is a schematic diagram showing an example of the configuration during the process of detecting the focus position of the projection optical system 3 according to the second embodiment.

[0122] As shown in Figure 8, in the exposure device 25 of this embodiment, the detection member holding unit 8 holds the detection member 17 so that it is perpendicular to the optical axis direction (Z direction) of the exposure light EL emitted from the light emitting unit 2.

[0123] In this embodiment, the detection member 17 shown in FIG. 2 is held by the detection member holding section 8 in the same orientation (posture) as in the comparative example shown in FIG.

[0124] Also, as shown in Figure 8, in this embodiment, the optical path length adjustment unit 9 is an optical element that is arranged between the detection element 17 and the projection optical system 3, and that continuously changes the optical path length of the exposure light EL from the light-transmitting region 20 to the projection optical system 3 as its position changes along the longitudinal axis direction from the first end 18 to the second end 19 of the first pattern 21.

[0125] In this embodiment, the optical member is constituted by a prism 26 having a predetermined refractive index, which is greater than 1.0, which is the refractive index of a vacuum.

[0126] 9 and 10 are schematic diagrams showing configuration examples of the prism 26. Fig. 9 is a side view of the prism 26 as seen from the front side along the depth direction (Y direction). This side view is a side view of the prism 26 as seen from the minor axis direction of the first pattern 21 of the detection member 17.

[0127] 10 is a bottom view of the prism 26 as seen from below along the optical axis direction (Z direction). This bottom view is a bottom view of the prism 26 as seen from the thickness direction of the detection member 17.

[0128] As shown in Figure 9, the prism 26 has an incident surface 27 onto which the exposure light EL emitted from the light-transmitting region 20 of the first pattern 21 is incident, and an exit surface 28 from which the exposure light EL incident on the incident surface 27 is emitted toward the projection optical system 3.

[0129] The incident surface 27 has a planar shape and is disposed so as to be perpendicular to the optical axis direction (Z direction) at a position facing the light transmitting region 20 of the first pattern 21. In this embodiment, the incident surface 27 of the prism 26 abuts against the detection member 17. However, the present invention is not limited to this configuration, and the prism 26 may be disposed at a distance from the detection member 17.

[0130] The exit surface 28 has a planar shape and is arranged obliquely with respect to the optical axis direction (Z direction) so that the distance in the optical axis direction (Z direction) from the entrance surface 27 changes continuously as the position changes along the long axis direction of the first pattern 21.

[0131] In this embodiment, the exit surface 28 is configured so that the distance from the entrance surface 27 continuously increases along the longitudinal direction of the first pattern 21 from the first end 18 side of the first pattern 21 toward the second end 19 side.

[0132] Therefore, as shown in Figures 9 and 10, the prism 26 is configured so that its size, i.e., thickness, in the optical axis direction (Z direction) increases from the first end 18 side toward the second end 19 side along the long axis direction of the first pattern 21.

[0133] The direction from the first end 18 side to the second end 19 side of the first pattern 21 is the direction from the left side to the right side in FIGS.

[0134] By disposing the prism 26 between the detection member 17 and the projection optical system 3, it is possible to continuously increase the optical path length of the exposure light EL from the light-transmitting region 20 to the projection optical system 3 at each position from the first end 18 to the second end 19 of the first pattern 21. In other words, it is possible to change the optical path length, similar to the configuration shown in FIG.

[0135] As a result, it is possible to achieve the same effects as those described in the first embodiment, and it is possible to perform focus control efficiently with high accuracy. For example, in cases where it is difficult to secure the space for arranging the detection member 17 at an angle, the arrangement of the prism 26 described in the second embodiment is effective. On the other hand, in cases where it is difficult to secure the space for arranging the prism 26, the configuration of holding the detection member 17 at an angle, described in the first embodiment, is effective.

[0136] [Examples of variations in detection components (detection patterns)] 11 to 15 are schematic diagrams showing variations of the detection pattern DP formed on the detection member 17. FIG.

[0137] The detection pattern DP shown in FIG. 11 includes a first end-side pattern 30 and a second end-side pattern 31 in addition to the first pattern 21.

[0138] The first end-side pattern 30 is a pattern made up of a light-transmitting region formed based on the position of the first end 18 of the first pattern 21. The first end-side pattern 30 can also be said to be a pattern formed to indicate the position of the first end 18 of the first pattern 21.

[0139] The second end-side pattern 31 is a pattern consisting of a light-transmitting region formed based on the position of the second end 19 of the first pattern 21. The second end-side pattern 31 can also be said to be a pattern formed to indicate the position of the second end 19 of the first pattern 21.

[0140] 11, a rectangular pattern extending in a direction perpendicular to the long axis direction of the first pattern 21, i.e., along the short axis direction of the first pattern 21, is formed as the first end-side pattern 30. The size of the first end-side pattern 30 in the long axis direction (the short axis direction of the first pattern 21) is smaller than the size of the first pattern 21 in the long axis direction.

[0141] As shown in Figure 11, the first end-side pattern 30 is formed so that the position of the left long side of the first end-side pattern 30 is equal to the position of the first end 18 of the first pattern 21 in the longitudinal axis direction of the first pattern 21.

[0142] 11, the second end-side pattern 31 is formed to have the same shape and size as the first end-side pattern 30. That is, the second end-side pattern 31 is made of a rectangular pattern extending along the minor axis direction of the first pattern 21.

[0143] As shown in Figure 11, the second end side pattern 31 is formed so that the position of the right long side of the second end side pattern 31 is equal to the position of the second end 19 of the first pattern 21 in the long axis direction of the first pattern 21.

[0144] By forming the first end side pattern 30 and the second end side pattern 31, it becomes possible to easily detect the positions of the first end 18 and the second end 19 of the first pattern 21 with high accuracy in the image 23 of the detection pattern DP as exemplified in Figure 6, etc.

[0145] That is, it is possible to easily detect with high accuracy the pixel corresponding to the first end 18 of the first pattern 21 and the pixel corresponding to the second end 19 of the first pattern 21. As a result, it is possible to easily detect with high accuracy the position between the first end 18 and the second end 19 to which the most focused pixel corresponds. As a result, it is possible to improve the detection accuracy of the focus position of the projection optical system 3.

[0146] The detection pattern DP shown in FIG. 12 includes a first pattern 21, a first end-side pattern 30, and a second end-side pattern 31, as well as an intermediate position pattern 33.

[0147] The intermediate position pattern 33 is a pattern consisting of a light-transmitting region formed based on a predetermined position along the longitudinal direction between the first end 18 and the second end 19 of the first pattern 21. The intermediate position pattern 33 can also be said to be a pattern formed to indicate a predetermined position between the first end 18 and the second end 19 of the first pattern 21.

[0148] 12, three intermediate position patterns 33 are formed, each having the same shape as the first end side pattern 30 and the second end side pattern 31. The three intermediate position patterns 33 are arranged at equal intervals between the first end side pattern 30 and the second end side pattern 31. The number, positions, etc. of the intermediate position patterns 33 are not limited and may be designed arbitrarily.

[0149] By forming the intermediate position pattern 33, it becomes possible to easily detect with high accuracy the position between the first end 18 and the second end 19 to which the most focused pixel corresponds in the image 23 of the detection pattern DP as exemplified in Fig. 6 etc. As a result, it becomes possible to improve the detection accuracy of the focus position of the projection optical system 3.

[0150] The shapes, sizes, etc. of the first end-side pattern 30, the second end-side pattern 31, and the intermediate position pattern 33 may be designed arbitrarily. For example, a circular pattern may be formed so that the center position is the same as a predetermined position from the first end 18 to the second end 19.

[0151] For example, a circular pattern whose center is located at the same position as the first end 18 may be formed as the first end side pattern 30. Also, a circular pattern whose center is located at the same position as the second end 19 may be formed as the second end side pattern 31. Also, a circular pattern whose center is located at the same position as a predetermined position between the first end 18 and the second end 19 may be formed as the intermediate position pattern 33.

[0152] Of course, the first end-side pattern 30, the second end-side pattern 31, and the intermediate position pattern 33 may be formed in different shapes or sizes. Furthermore, when multiple intermediate position patterns 33 are formed, these multiple intermediate position patterns 33 may be formed in different shapes or sizes.

[0153] The detection pattern DP shown in Fig. 13 includes a plurality of first patterns 21. In the example shown in Fig. 13, the plurality of first patterns 21 having the same shape are formed so as to be aligned at equal intervals along the minor axis direction of the first patterns 21. In the major axis direction of the first patterns 21, the first end portions 18 of the plurality of first patterns 21 are aligned at the same position. Furthermore, the second end portions 19 of the plurality of first patterns 21 are also aligned at the same position. The detection pattern shown in Fig. 13 can also be said to be a line and space pattern.

[0154] By forming a plurality of first patterns 21, it becomes possible to detect the most focused pixel in the image of each first pattern 21 in the image 23 of the detection pattern DP as exemplified in Fig. 6 etc. Based on the positions of these detected most focused pixels, it becomes possible to detect the focus position of the projection optical system 3 with high accuracy.

[0155] The detection pattern DP shown in FIG. 14 includes three first end-side patterns 30a to 30c and three second end-side patterns 31a to 31c in addition to the plurality of first patterns 21 shown in FIG.

[0156] The three first end-side patterns 30a to 30c are formed so as to connect, along the minor axis direction, the first end portions 18 of two adjacent first patterns 21. In this example, the first end-side pattern 30a is formed so as to connect the first end portion 18 of the first pattern 21 formed second from the top in the figure to the first end portion 18 of the first pattern 21 formed third from the top in the figure.

[0157] Furthermore, the first end-side pattern 30b is formed so as to connect the first end 18 of the first pattern 21 formed fourth from the top in the figure to the first end 18 of the first pattern 21 formed fifth in the figure. Furthermore, the first end-side pattern 30c is formed so as to connect the first end 18 of the first pattern 21 formed sixth from the top in the figure to the first end 18 of the first pattern 21 formed seventh in the figure.

[0158] As shown in Figure 14, the second end side pattern 31a is formed so as to connect the second end 19 of the first pattern 21 formed first from the top in the figure to the second end 19 of the first pattern 21 formed second in the figure.

[0159] In addition, the second end side pattern 31b is formed so as to connect the second end 19 of the first pattern 21 formed third from the top in the figure to the second end 19 of the first pattern 21 formed fourth in the figure. In addition, the second end side pattern 31c is formed so as to connect the second end 19 of the first pattern 21 formed fifth from the top in the figure to the second end 19 of the first pattern 21 formed sixth in the figure.

[0160] In this way, it is also possible to form the detection pattern DP including the first pattern 21, the first end-side pattern 30, and the second end-side pattern 31 in a so-called unicursal form. Because it is a unicursal form, it is possible to easily form the detection pattern DP.

[0161] The detection pattern DP shown in FIG. 15 includes three first patterns 21, one first end-side pattern 30, one second end-side pattern 31, and one intermediate position pattern 33.

[0162] The three first patterns 21 have the same shape and are formed so as to be aligned at equal intervals along the minor axis direction of the first patterns 21. In the major axis direction of the first patterns 21, the first end portions 18 of each of the multiple first patterns 21 are aligned at the same position. In addition, the second end portions 19 of each of the multiple first patterns 21 are also aligned at the same position.

[0163] 15, the first end-side pattern 30 is formed to connect the first end portions 18 of the three first patterns 21 along the minor axis direction. The second end-side pattern 31 is formed to connect the second end portions 19 of the three first patterns 21 along the minor axis direction. The intermediate position pattern 33 is formed to connect the central portions of the three first patterns 21 along the minor axis direction.

[0164] 15 is a pattern in which a cross-shaped pattern intersecting at the center of a rectangular frame is formed inside the pattern. In this way, it is possible to adopt detection patterns DP having various shapes.

[0165] 11 to 15 can be used in both the first and second embodiments. That is, it can be applied to both the case where the detection member holder 8 functions as the optical path length adjuster 9 and holds the detection member 17 at an angle to the optical axis direction (Z direction), and the case where a prism 26 is used as the optical path length adjuster 9.

[0166] <Third embodiment> 16 is a schematic diagram showing an example of the configuration of a detection member 17 (detection pattern DP) according to the third embodiment of the present invention. The detection pattern DP shown in FIG. 16 includes three first patterns 21 and three second patterns 35.

[0167] The three first patterns 21 have the same shape and are formed so as to be aligned at equal intervals along the minor axis direction of the first patterns 21. In the major axis direction of the first patterns 21, the first end portions 18 of each of the multiple first patterns 21 are aligned at the same position. In addition, the second end portions 19 of each of the multiple first patterns 21 are also aligned at the same position.

[0168] The second pattern 35 has a third end 36 and a fourth end 37 that face each other in a direction perpendicular to the long axis direction of the first pattern 21 (the short axis direction of the first pattern 21), and is a pattern in which a light-transmitting region 38 is formed continuously from the third end 36 to the fourth end 37 so that the direction perpendicular to the long axis direction of the first pattern 21 (the short axis direction of the first pattern 21) is the long axis direction.

[0169] 16, in this embodiment, three first patterns 21 are formed in an area H1 in the upper half of the detection member 17 in the drawing. Also, three second patterns 35a to 35c are formed in an area H2 in the lower half of the detection member 17 in the drawing.

[0170] The three second patterns 35a to 35c have the same shape and are rectangular with their major axes aligned in the minor axis direction of the first pattern 21. The three second patterns 35a to 35c are formed so as to be aligned at equal intervals along the major axis direction of the first pattern 21.

[0171] The second pattern 35a on the left side of the figure is formed based on the positions of the first ends 18 of the three first patterns 21, and also functions as the first end-side pattern 30 shown in Figure 12 and other figures. The second pattern 35c on the right side of the figure is formed based on the positions of the second ends 19 of the three first patterns 21, and also functions as the second end-side pattern 31 shown in Figure 12 and other figures. The second pattern 35b in the center is formed based on the position of the center part of the three first patterns 21, and also functions as the intermediate position pattern 33 shown in Figure 12 and other figures.

[0172] In this embodiment, two types of prisms are arranged as the optical path length adjuster 9 for the detection member 17 shown in Fig. 16. Specifically, as schematically shown in Fig. 16, in the upper half region H1 in the figure where three first patterns 21 are formed, first prisms whose thickness increases along the long axis direction of the first patterns 21 are arranged.

[0173] On the other hand, in the lower half region H2 in the figure where three second patterns 35 are formed, second prisms with a larger thickness are arranged along the long axis direction of the second patterns 35 (the short axis direction of the first patterns 21).

[0174] 17 to 20 are schematic diagrams showing configuration examples of the first prism 41 and the second prism 42. FIG. FIG. 17 is a diagram of the first prism 41 and the second prism 42 when viewed from the left side of the detection member 17 shown in FIG. FIG. 18 is a diagram of the first prism 41 and the second prism 42 when viewed from the upper side of the detection member 17 shown in FIG. FIG. 19 is a diagram of the first prism 41 and the second prism 42 when viewed from the right side of the detection member 17 shown in FIG. FIG. 20 is a diagram of the first prism 41 and the second prism 42 when viewed from the lower side of the detection member 17 shown in FIG.

[0175] The first prism 41 has a shape approximately equal to that of the prism 26 shown in Figure 9, and has an entrance surface 43 which is planar and arranged perpendicular to the optical axis direction (Z direction), and an exit surface 44 which is planar and arranged obliquely to the optical axis direction (Z direction).

[0176] The second prism 42 also has a shape approximately the same as that of the prism 26 shown in Figure 9, and has an entrance surface 45 that is planar and arranged perpendicular to the optical axis direction (Z direction), and an exit surface 46 that is planar and arranged obliquely to the optical axis direction (Z direction).

[0177] The first prism 41 and the second prism 42 are connected to each other so that the inclination directions (directions in which the thickness of the prisms changes) of the exit surfaces 44 and 46 are perpendicular to each other. The inclination angles of the exit surfaces 44 and 46 of the first prism 41 and the second prism 42 are different.

[0178] The first prism 41 is disposed between the region H1 where the first pattern 21 of the detection member 17 is formed and the projection optical system 3, and corresponds to one embodiment of a first optical member that continuously changes the optical path length of the exposure light EL from the light-transmitting region 20 of the first pattern 21 to the projection optical system 3 as the position changes along the long axis direction of the first pattern 21 from the first end 18 of the first pattern 21 toward the second end 19 of the first pattern 21.

[0179] The second prism 42 is disposed between the region H2 where the second pattern 35 of the detection member 17 is formed and the projection optical system 3, and corresponds to one embodiment of a second optical member that continuously changes the optical path length of the exposure light EL from the light-transmitting region 38 of the second pattern 35 to the projection optical system 3 as its position changes along the long axis direction of the second pattern 35 from the third end 36 to the fourth end 37 of the second pattern 35.

[0180] As shown in Fig. 17, when the first prism 41 and the second prism 42 are viewed from the left side of the detection member 17 shown in Fig. 16, the first prism 41 is visible on the left side and the second prism 42 is visible on the right side. Furthermore, with regard to the first prism 41, an exit surface 44 extending toward the rear and downward can be seen. With regard to the second prism 42, an exit surface 46 can be seen to be inclined toward the right and upward.

[0181] As shown in Fig. 18, when the first prism 41 and the second prism 42 are viewed from the top side of the detection member 17 shown in Fig. 16, the first prism 41 is visible on the front side and the second prism 42 is visible on the back side. Furthermore, with regard to the first prism 41, it appears that the light exit surface 44 is inclined upward and to the right. With regard to the second prism 42, the side surface with the greatest thickness is visible.

[0182] As shown in Fig. 19, when the first prism 41 and the second prism 42 are viewed from the right side of the detection member 17 shown in Fig. 16, the first prism 41 is visible on the right side and the second prism 42 is visible on the left side. The side of the first prism 41 where the thickness is greatest is also visible. The second prism 42 has an exit surface 46 that is tilted upward and to the left.

[0183] 20, when the first prism 41 and the second prism 42 are viewed from the bottom side of the detection member 17 shown in FIG. 16, the second prism 42 is visible on the near side, and the first prism 41 is hidden by the second prism 42. Furthermore, with respect to the second prism 42, an exit surface 46 extending toward the rear and downward side is visible.

[0184] In this manner, in this embodiment, a first pattern 21 and a second pattern 35 are formed whose long axis directions are perpendicular to each other, and the optical path length of the exposure light EL to the projection optical system 3 is continuously changed at different positions in the long axis direction in each pattern.

[0185] This makes it possible to detect the focus position of the projection optical system 3 in each of two different directions (the long axis direction of the first pattern 21 and the long axis direction of the second pattern 35) based on the images of the first pattern 21 and the second pattern 35 captured by the detection pattern capturing unit 10.

[0186] This enables focus control with even higher accuracy. Also, based on information on the focus position in two directions, it becomes possible to correct aberrations such as astigmatism of the projection optical system 3, thereby further improving exposure accuracy. Note that correction of aberrations such as astigmatism of the projection optical system 3 can be performed by adjusting the projection optical system 3 using the projection optical system adjustment mechanism 7, for example.

[0187] 21 is a schematic diagram showing another configuration example of the detection member 17 (detection pattern DP). The detection pattern DP shown in FIG.

[0188] The three first patterns 21 have the same shape and are formed so as to be aligned at equal intervals along the minor axis direction of the first patterns 21. In the major axis direction of the first patterns 21, the first end portions 18 of each of the multiple first patterns 21 are aligned at the same position. In addition, the second end portions 19 of each of the multiple first patterns 21 are also aligned at the same position.

[0189] 21, the second pattern 35 on the left side in the drawing is formed so as to connect the first end portions 18 of the three first patterns 21 along the minor axis direction. The second pattern 35 also functions as the first end portion side pattern 30 in FIG. 12 etc.

[0190] The second pattern 35 on the right side in the figure is formed so as to connect, along the minor axis direction, the second end portions 19 of the three first patterns 21. The second pattern 35 also functions as the second end portion side pattern 30 shown in FIG.

[0191] The two second patterns 35 in the center of the figure are formed so as to connect, along the minor axis direction, portions of the three first patterns 21 at predetermined positions between the first end 18 and the second end 19. The two second patterns 35 also function as intermediate position patterns 33 shown in FIG. 2 and other figures.

[0192] The first prism 41 and the second prism 42 described with reference to FIGS. 16 to 20 may be disposed on the detection member 17 shown in FIG. 21 to adjust the optical path length.

[0193] In the present disclosure, the "region where the first pattern is formed" includes a region where at least a part of the first pattern 21 is formed. Also, the "region where the second pattern is formed" includes a region where at least a part of the second pattern 35 is formed.

[0194] Therefore, the upper half region H1 of the detection member 17 shown in Fig. 21 is included in the "region where the first pattern is formed," and the lower half region H2 of the detection member 17 shown in Fig. 21 is included in the "region where the second pattern is formed."

[0195] In this way, a first prism 41 that continuously changes the optical path length of the exposure light EL in the major axis direction of the first pattern 21 may be arranged in a region where at least a part of the first pattern 21 and at least a part of the second pattern 35 are both present. Also, a second prism 42 that continuously changes the optical path length of the exposure light EL in the major axis direction of the second pattern 35 may be arranged in a region where at least a part of the first pattern 21 and at least a part of the second pattern 35 are both present.

[0196] Even when such a configuration is adopted, it is possible to detect the focus position of the projection optical system 3 in each of the major axis directions of the first pattern 21 and the second pattern 35, enabling highly accurate focus control. It is also possible to correct aberrations of the projection optical system 3.

[0197] 11, 12, 14, and 15, all or part of the first end-side pattern 30, the second end-side pattern 31, and the intermediate position pattern 33 can be regarded as the second pattern 35. Therefore, the detection member 17 on which these detection patterns DP are formed can also be used in the third embodiment.

[0198] In addition, the specific configuration of the first pattern 21 and the second pattern 35, the specific configuration of the first prism 41 and the second prism 42, the specific arrangement method of the first prism 41 and the second prism 42, etc. can be designed arbitrarily.

[0199] <Other embodiments> The present invention is not limited to the above-described embodiment, and various other embodiments can be realized.

[0200] The optical path length adjustment unit 9 may have a configuration in which the image sensor of the detection pattern photographing unit 10 is arranged tilted with respect to the optical axis direction (Z direction).

[0201] In the above, rectangular patterns have been given as examples of the first pattern 21 and the second pattern 35. Of course, this is not limiting, and any pattern in which a light-transmitting region is formed continuously from the first end 18 to the second end 19 can be adopted as the first pattern 21. Also, any pattern in which a light-transmitting region is formed continuously from the third end 36 to the fourth end 37 can be adopted as the second pattern 35. For example, various shapes that can define the major axis direction, such as an elliptical shape or a polygonal shape, can be adopted.

[0202] By performing exposure using the exposure apparatus according to the present invention, it is possible to manufacture various substrates on which predetermined patterns are formed as components, such as electrical circuit elements, optical elements, MEMS, recording elements, sensors, or molds. Examples of the electric circuit element include volatile or non-volatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, as well as semiconductor elements such as LSI, CCD, image sensor, and FPGA. Examples of the mold include a mold for imprinting.

[0203] The configurations of the exposure apparatus, control device, detection member, detection pattern, detection member holder, optical path length adjuster, detection pattern photographing unit, etc., as well as alignment control, focus control, adjustment of optical path length, detection of focus position of the projection optical system, etc., described with reference to the drawings are merely one embodiment and can be modified as desired without departing from the spirit of the present invention. In other words, any other configurations, processing flows, algorithms, etc. for implementing the present invention may be adopted.

[0204] In this disclosure, terms such as "approximately" are used as appropriate to facilitate understanding of the explanation. However, there is no clear difference between using and not using terms such as "approximately." In other words, in this disclosure, concepts that define shape, size, positional relationship, state, etc., such as "center," "middle," "equal," "same," "orthogonal," and "parallel," include concepts such as "substantially center," "substantially central," "substantially equal," "substantially the same," "substantially orthogonal," and "substantially parallel."

[0205] In the present disclosure, expressions using "more than," such as "greater than A" and "smaller than A," are expressions that comprehensively include both concepts that include equivalent to A and concepts that do not include equivalent to A. For example, "greater than A" is not limited to cases that do not include equivalent to A, but also includes "A or greater." Furthermore, "smaller than A" is not limited to "less than A," but also includes "A or less." When implementing the present invention, specific settings and the like can be appropriately adopted from the concepts included in "greater than A" and "smaller than A" so as to achieve the effects described above.

[0206] It is also possible to combine at least two of the features of the present technology described above. That is, the various features described in each embodiment may be arbitrarily combined without distinction between the embodiments. Furthermore, the various effects described above are merely examples and are not limiting, and other effects may also be achieved. [Explanation of symbols]

[0207] DP: Detection pattern EL: exposure light H1: Area where the first pattern is formed H2: Area where the second pattern is formed M... exposure mask (mask) MS...Mask Stage W…Work WS...Work Stage 1, 25... exposure equipment 2...Light emitting part 3...Projection optical system 8...Detection member holding portion 9...Optical path length adjustment section 10...Detection pattern photographing unit 17...Detection member 18...First end 19...Second end 20...Light-transmitting region of first pattern 21...First pattern 23...Image of detection pattern 26...Prism 27...Incidence plane 28...Exit surface 30...First end side pattern 31...Second end pattern 33...Intermediate position pattern 35...Second pattern 36...Third end 37...Fourth end 38...light transmitting area of second pattern 41...First Prism 42...Second Prism 43... Entrance surface of first prism 44...Output surface of first prism 45... Entrance surface of second prism 46...Exit surface of second prism

Claims

1. a light emitting section that emits exposure light; a mask stage for holding an exposure mask; a work stage for holding the work; a projection optical system that irradiates the workpiece held on the workpiece stage with the exposure light that has been emitted from the light emitting unit and transmitted through the exposure mask; a holding unit that holds a detection member on which a detection pattern for focus detection is formed, in an optical path of the exposure light from the light exit unit to the projection optical system during the step of detecting a focus position of the projection optical system; an imaging unit that is disposed in an optical path of the exposure light emitted from the projection optical system during the step of detecting a focus position of the projection optical system, and that captures an image of the detection pattern of the detection member held by the holding unit; Optical path length adjustment unit Equipped with the detection pattern includes a first pattern having a first end and a second end facing the first end in a predetermined direction, in which a light transmitting region is continuously formed from the first end to the second end such that the predetermined direction is a major axis direction; The optical path length adjusting unit continuously changes the optical path length of the exposure light from the light transmitting region to the projection optical system as the position of the first pattern formed on the detection member held by the holding unit changes along the long axis direction from the first end toward the second end. Exposure equipment.

2. 2. The exposure apparatus according to claim 1, The optical path length adjusting unit continuously increases or decreases the optical path length of the exposure light from the light transmitting region to the projection optical system as the position of the first pattern changes along the long axis direction from the first end to the second end. Exposure equipment.

3. 2. The exposure apparatus according to claim 1, the detection member is made of a flat plate member on which the detection pattern is formed, The holding unit functions as the optical path length adjusting unit, and holds the detection member obliquely with respect to the optical axis direction so that as the position of the detection member changes from the first end portion to the second end portion of the first pattern along the long axis direction, the distance in the optical axis direction of the exposure light emitted from the light emitting unit from the light transmitting region to the projection optical system changes continuously. Exposure equipment.

4. 2. The exposure apparatus according to claim 1, the detection member is made of a flat plate member on which the detection pattern is formed, the holding portion holds the detection member so as to be perpendicular to an optical axis direction of the exposure light emitted from the light emitting portion, The optical path length adjusting unit is disposed between the detection member and the projection optical system, and has an optical member that continuously changes the optical path length of the exposure light from the light transmitting region to the projection optical system as the position of the first pattern changes along the major axis direction from the first end toward the second end. Exposure equipment.

5. 5. The exposure apparatus according to claim 4, the optical member has an incident surface through which the exposure light emitted from the light-transmitting region of the first pattern enters, and an exit surface through which the exposure light incident on the incident surface exits toward the projection optical system, the incident surface has a planar shape and is disposed so as to be perpendicular to the optical axis direction at a position facing the light transmitting region of the first pattern, The exit surface has a planar shape and is disposed obliquely with respect to the optical axis direction so that the distance in the optical axis direction from the entrance surface changes continuously as the position of the exit surface changes along the major axis direction of the first pattern. Exposure equipment.

6. 6. The exposure apparatus according to claim 5, The optical member is composed of a prism having a predetermined refractive index. Exposure equipment.

7. 2. The exposure apparatus according to claim 1, The detection pattern includes a first end-side pattern formed with the position of the first end of the first pattern as a reference and consisting of a light-transmitting region, and a second end-side pattern formed with the position of the second end of the first pattern as a reference and consisting of a light-transmitting region. Exposure equipment.

8. 8. The exposure apparatus according to claim 7, The detection pattern includes an intermediate position pattern formed with a light-transmitting region based on a predetermined position along the long axis direction between the first end and the second end of the first pattern. Exposure equipment.

9. 2. The exposure apparatus according to claim 1, The first pattern has a rectangular shape extending along the long axis direction. Exposure equipment.

10. 2. The exposure apparatus according to claim 1, The detection pattern includes a plurality of first patterns. Exposure equipment.

11. 2. The exposure apparatus according to claim 1, The detection pattern includes a second pattern having a third end and a fourth end facing each other in a direction perpendicular to the long axis direction of the first pattern, and a light transmitting region formed continuously from the third end to the fourth end such that the direction perpendicular to the long axis direction of the first pattern is the long axis direction. Exposure equipment.

12. 12. The exposure apparatus according to claim 11, The detection pattern includes a plurality of second patterns. Exposure equipment.

13. 2. The exposure apparatus according to claim 1, the detection member is made of a flat plate member on which the detection pattern is formed, the holding portion holds the detection member so as to be perpendicular to an optical axis direction of the exposure light emitted from the light emitting portion, The optical path length adjustment unit a first optical member that is disposed between an area of the detection member where the first pattern is formed and the projection optical system, and that continuously changes the optical path length of the exposure light from the light transmission area of the first pattern to the projection optical system as the position of the first optical member changes along the major axis direction of the first pattern from the first end toward the second end of the first pattern; a second optical member that is disposed between an area of the detection member where the second pattern is formed and the projection optical system, and that continuously changes the optical path length of the exposure light from the light transmission area of the second pattern to the projection optical system as the position of the second pattern changes along the major axis direction of the second pattern from the third end toward the fourth end of the second pattern. Exposure equipment.

Images