Adaptive optical element with insertion element

Abstract

The present invention relates to an adaptive optical element (100) for a microlithography projection exposure apparatus (600, 700), comprising a substrate (101), an optically effective surface (102), and at least one solid actuator (103) that flexes or deforms the optically effective surface (102) at least partially. There is at least one hole (104) penetrating at least a portion of the substrate (101). There is an insertion element (105) including at least one solid actuator (103). The insertion element (105) is designed and housed in the hole (104) such that at least one solid actuator (103) is positioned and fixed in a predetermined location within the hole (194).

Description

Technical Field

[0001] This application claims the priority of German Patent Application No. 10 2023 202 339.3 filed on March 15, 2023. The entire disclosure of the said patent application is incorporated herein by reference.

[0002] The present invention relates to an adaptive optical element, particularly an adaptive mirror or lens element, of a microlithographic projection exposure apparatus, which has a substrate, an optically effective surface irradiated with electromagnetic radiation, and at least one solid actuator for at least partially deflecting or deforming the optically effective surface.

Background Art

[0003] Projection exposure apparatuses are used for manufacturing extremely fine structures, particularly semiconductor components or other fine-structured components. The operating principle of this apparatus is generally to produce extremely fine structures on the order of nanometers by reducing and imaging the structures on a mask, a so-called reticle, onto a structured target element, a so-called wafer, provided with a photosensitive material. The minimum dimension of the structures to be manufactured directly depends on the wavelength of the light used. This light is shaped in the illumination optical unit to optimally illuminate the reticle. In recent years, the use of light sources having emission wavelengths of about several nanometers, for example, 1 nm to 120 nm, particularly about 13.5 nm, has been increasing. The above wavelength range is also referred to as the EUV range.

[0004] In addition to using systems operating in the EUV range, commercially established DUV systems having wavelengths of 100 nm to 300 nm, particularly 193 nm, may also be used for manufacturing fine-structured components. Due to the requirement for miniaturization of the structures that can be manufactured, the requirements for optical correction of the systems are also further increasing. In order to improve profitability, the throughput of projection exposure apparatuses in the EUV range or the DUV range has been improving for each new generation. As a result, the thermal load usually increases, and thus the imaging aberration due to heat also increases.

[0005] To at least partially compensate for the above problems and to generally improve image position accuracy and image quality (both in the optical axis, i.e., the direction of light propagation, and in the transverse direction, i.e., the direction perpendicular to the optical axis or the direction of light propagation), it is known that one or more mirrors in an optical system may be specifically designed as adaptive mirrors having at least one actuator, in particular a solid actuator made of a piezoelectric, ferroelectric, electrostrictive, or magnetostrictive material. For example, by applying a voltage to electrodes positioned on both sides of the piezoelectric layer, an electric field of locally varying intensity is generated in the piezoelectric layer. When the piezoelectric layer deforms locally, the optically effective surface of the adaptive element also deforms, and as a result, imaging aberrations can be at least partially compensated by appropriate (and possibly temporally variable) control of the electrodes. Generally, deformation of the optical surface can also be used to further optimize the microlithography imaging process.

[0006] All solid actuators must be fixed to the adaptive optical elements. Adhesives are typically used for this purpose, and in the case of adaptive mirrors, the actuator device is positioned between the mirror substrate and the reflective layer system or intermediate layer and fixed using adhesive. In this case, the adaptive mirror is usually manufactured in layers. The manufacturing of such adaptive optical elements is very complex and prone to errors. Since the solid actuators themselves often have mechanical and electrical tolerances, efforts must be made to compensate for these through the bonding process. Furthermore, the bonding process itself can also lead to deviations due to differences in the amount of adhesive used, differences in adhesive application methods, differences in adhesive gaps, and moisture absorption of the adhesive. Additional moisture absorption or release can also cause the specifications of the solid actuator, and especially the maximum travel, to change over the lifespan of the optical element.

[0007] Such adaptive mirrors are known from the prior art, for example from Patent Documents 1, 2, and 3. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] German Patent Application Publication No. 10 2016 209 847 Specification [Patent Document 2] European Patent No. 1191377 [Patent Document 3] German Patent Application Publication No. 10 2017 208 364 Specification [Overview of the project] [Problems that the invention aims to solve]

[0009] The problem addressed by the present invention is to overcome or at least mitigate the aforementioned drawbacks. [Means for solving the problem]

[0010] This problem is solved by an adaptive optical element having the features described in claim 1. Advantageous configurations, along with favorable improved forms, are described in the dependent claims.

[0011] The adaptive optical element is characterized in that, in particular, there is at least one hole penetrating at least a portion of the substrate, there is an insert element containing at least one solid actuator, and the insert element is designed and housed in the hole such that at least one solid actuator is positioned in a predetermined location within the hole and preferably fixed by adhesive means. In particular, a hole embodied as an elongated hole provides a space of predetermined dimensions that can accommodate a solid actuator. Therefore, the effect of mechanical displacement of the solid actuator is reduced. Since the configuration, in particular the length of the insert element, determines the position of the solid actuator within the hole, from a process technology viewpoint, housing the actuator is easier with an insert element containing at least one solid actuator. The solid actuator can also be formed as an actuator stack having a plurality of interconnected solid actuator elements. The solid actuator or solid actuator element can be formed from piezoelectric, electrostrictive, magnetostrictive, or ferroelectric material.

[0012] Each of the insertion elements or multiple insertion elements may be formed by a single solid actuator having dimensions that substantially coincide with the depth of the hole in which it is housed, i.e., dimensions that substantially correspond to the depth of the hole. In this case, the solid actuator may also be formed as an actuator stack having multiple interconnected solid actuator elements, as already mentioned above. In this case, the dimensions of the actuator stack preferably coincide with the dimensions of the hole, and in particular its depth.

[0013] Alternatively, the inset element preferably includes at least one spacer connected to at least one solid actuator. In this regard, the spacer may be formed as a printed circuit board or as a flexible substrate. Furthermore, a passage for arranging the electrical connector of the solid actuator may be formed in the spacer. The inset element may include any desired number of spacers. In particular, the inset element may include spacers at both ends or at least one end.

[0014] Furthermore, it is preferable that the insertion element includes multiple solid actuators or multiple actuator stacks, and that two adjacent solid actuators / actuator stacks are connected to each other by spacers. This allows multiple solid actuators to be housed in an adaptive optical element and positioned simply and reproducibly in predetermined locations.

[0015] In this regard, it is advantageous if at least the individual or all spacers are formed to be flexible. This allows for compensation of manufacturing tolerances that may occur during the fabrication of the insert and hole. Furthermore, as a result, the robustness and durability of the insert, and consequently the solid actuator, are increased.

[0016] In this case, it is preferable that the length of the insertion element matches the depth of the hole. Therefore, the length of the insertion element and the position of each solid actuator within the hole can be defined by changing the number and / or dimensions (particularly the length) of the spacers and / or the number and / or dimensions (particularly the longitudinal spread of the hole) of the solid actuators. In one embodiment, it is preferable that the length of the insertion element substantially corresponds to the depth of the hole. In other embodiments, it is advantageous that the length of the insertion element is shorter than the depth of the hole.

[0017] Alternatively or in addition, the insert element may also be formed as a sleeve in which at least one solid actuator is placed. The sleeve may be made of metal and may include an EDM cutout. This facilitates the housing and positioning of the solid actuator or actuator stack within the hole and increases the robustness of the insert element.

[0018] Alternatively or in addition, the insert element may also be formed as a rail or spoke on which at least one solid actuator or a plurality of solid actuators / actuator stacks are mounted spaced apart.

[0019] At least one hole may extend into the substrate as desired. To deform the optically effective surface under sufficient control, it is advantageous that at least one hole extends substantially parallel to the optically effective surface in at least a portion of the substrate.

[0020] However, alternatively, depending on the embodiment of the adaptive optical element, particularly the optically effective surface, it may be advantageous if at least one hole extends tangentially to the optically effective surface in at least a portion of the substrate. Similarly, multiple holes may be formed radially with respect to the optically effective surface.

[0021] In this regard, it is advantageous that the profile of at least one hole at least partially coincides with the contour of the substrate or optically effective surface.

[0022] To simplify the supply of the bonding means to the inner surface of the hole, and thus to simplify the fixing of the insertion element and / or the solid actuator, it is preferable that at least one access hole fluidly connected to at least one hole is provided for feeding the bonding means into the hole. The bonding means is preferably formed as an adhesive consisting of or containing an epoxy resin. Further, it is preferable that the number of access holes present coincides with the number of solid actuators or the number of actuator stacks.

[0023] When the insertion element is accommodated in at least one hole, in order to prevent the absorption or release of liquid, that is, to form a closed system, it is preferable that all holes (i.e., access holes and holes) are sealed liquid-tightly and / or air-tightly. For example, this can be achieved by sealing means, particularly by a closure or plug made of glass, for example.

[0024] Alternatively, a stable system can also be formed by the presence of at least one media opening fluidly connected to at least one hole for feeding gas, particularly air, or fluid into the hole. By supplying a constant air flow or gas flow, the humidity in the adaptive optical element can be kept constant. In this case, it is particularly preferable that at least two media openings fluidly connected to the hole are present in each hole. If a spacer is present, it can also have recesses for media guidance.

[0025] To reduce the mechanical stress in the substrate, a notch can be formed in the substrate adjacent to the openings in the substrate, that is, the holes, the access holes that may be present, and the media openings. This also reduces the effects such as the shrinkage of the adhesive or the expansion of the adhesive or the substrate.

[0026] At least one hole or at least one of the holes can be formed as a blind hole or as a through hole penetrating the substrate. The first part of the hole may be formed as a blind hole, and the second part of the hole may be formed as a through hole.

[0027] In particular, it is advantageous if there are multiple holes that are spaced apart from each other and penetrate at least a portion of the substrate, and each hole accommodates an inserted element containing at least one solid actuator. In this case, the direction of extension of the holes can be formed as desired within the substrate.

[0028] Furthermore, to form the actuator grid, it is preferable that there be a first layer having a plurality of first holes containing inserted elements, and a second layer adjacent to the first layer having a plurality of second holes containing inserted elements, and that the extending direction of the first holes is offset from the extending direction of the second holes. This allows for flat, particularly controllable, deformation of the optically effective surface. In this case, it is preferable that the extending direction of the first holes is perpendicular to the extending direction of the second holes.

[0029] Further features, characteristics, and advantages of the present invention will be described in more detail below with reference to the accompanying drawings, based on modified embodiments. In this regard, all of the features described above and below are advantageous individually or in any desired combination. The modified embodiments described below are merely examples and do not limit the subject matter of the present invention. [Brief explanation of the drawing]

[0030] [Figure 1a] This shows a schematic diagram of a microlithography projection exposure system designed for EUV operation. [Figure 1b] A schematic diagram of a microlithography projection exposure system designed for DUV operation is shown. [Figure 2] A schematic diagram of an exemplary first embodiment of an adaptive optical element in the form of an adaptive mirror is shown. [Figure 3] A schematic diagram of a second exemplary embodiment of an adaptive optical element in the form of an adaptive mirror is shown. [Figure 4] A schematic diagram of a third exemplary embodiment of an adaptive optical element in the form of an adaptive mirror is shown. [Figure 5] A schematic diagram of a fourth exemplary embodiment of an adaptive optical element in the form of an adaptive mirror is shown. [Figure 6]A schematic diagram of a fifth exemplary embodiment of an adaptive optical element in the form of an adaptive mirror is shown. [Modes for carrying out the invention]

[0031] Figure 1a shows a schematic diagram of an exemplary projection exposure apparatus 600 designed for EUV operation in which the present invention can be implemented, i.e., in which the actuator 100 according to the present invention can be used. However, the present invention can also be used in other nanopositioning systems.

[0032] As shown in Figure 1a, the illumination system of the projection exposure apparatus 600 designed for EUV includes a field-of-view facet mirror 603 and a pupil facet mirror 604. Light from a light source unit including a plasma light source 601 and a collector mirror 602 is directed to the field-of-view facet mirror 603. A first telescopic mirror 605 and a second telescopic mirror 606 are positioned in the optical path downstream of the pupil facet mirror 604. A deflection mirror 607 is positioned downstream of the optical path, which directs the incident radiation to the object field of view on the object plane of the projection lens, which includes six mirrors 651-656. At the location of the object field of view, a reflective structure-supported mask 621 is positioned on the mask stage 620 and imaged onto the image plane using a projection lens, where a substrate 661 coated with a photosensitive layer (photoresist) is located on the wafer stage 660. One or more of the mirrors of the projection exposure apparatus 600 designed for EUV may be formed as an adaptive optical element 100 according to the present invention.

[0033] The present invention can also be used in a DUV apparatus, as shown in Figure 1b. In principle, a DUV apparatus is set up in the same way as the EUV apparatus described above, as shown in Figure 1a, and mirrors and lens elements can be used as optical elements in a DUV apparatus. The light source of the DUV apparatus emits radiation in the wavelength range of 100 nm to 300 nm.

[0034] The DUV lithography apparatus 700 shown in Figure 1b has a DUV light source 701. For example, an ArF excimer laser emitting radiation 702 in the DUV region of 193 nm can be provided as the DUV light source 701. A beam shaping and illumination system 703 guides the DUV radiation 702 to a photomask 704. The photomask 704 is embodied as a transmissive optical element and can be placed outside the system 703. The photomask 704 has a structure that is reduced and imaged onto a wafer 706, etc., by a projection system 705. The projection system 705 includes a plurality of lens elements 707 and / or mirrors 708 for imaging the photomask 704 onto the wafer 706. In this case, the individual lens elements 707 and / or mirrors 708 of the projection system 705 can be arranged symmetrically with respect to the optical axis 709 of the projection system 705. It should be noted that the number of lens elements 707 and mirrors 708 in the DUV lithography apparatus 700 is not limited to the number shown. The number of lens elements 707 and / or mirrors 708 provided may be increased or decreased. In particular, the beam shaping and illumination system 703 of the DUV lithography apparatus 700 includes multiple lens elements 707 and / or mirrors 708. Furthermore, the mirrors are generally curved on the front side for beam shaping purposes. The air gap 710 between the last lens element 707 and the wafer 706 can be replaced with a liquid medium having a refractive index > 1. The liquid medium can be, for example, high-purity water. Such a configuration is also called immersion lithography and has high photolithographic resolution. The adaptive optical element 100 according to the present invention can be used to deform the mirrors or lens elements of the DUV lithography apparatus 700, in particular its projection system 705.

[0035] Figure 2 shows an optical element 100 according to the present invention, formed as an adaptive mirror for a microlithography projection exposure apparatus 600, 700, and having a substrate 101 and an optically effective surface 102 irradiated with electromagnetic radiation. At least one hole 104 is formed in the substrate 101, which accommodates an insertion element 105. The insertion element 105 includes a plurality of solid actuators 103, each having a plurality of interconnected solid actuator elements stacked vertically, in this case a series-connected actuator stack of five. The solid actuators 103 are formed as piezoelectric actuators, but may be formed from electrostrictive, magnetostrictive, or ferroelectric materials. Two solid actuators 103 or actuator stacks are each connected to one another by spacers 106, and together with additional spacers 106 formed at the ends, form the insertion element 105 in this embodiment. The hole 104 is formed as a blind hole in this embodiment, but may also be formed as a through hole penetrating the substrate 101. In this case, the length of the insertion element 105 may be influenced or defined by the number and / or dimensions of the solid actuators / actuator stacks 103 used (particularly their lengths along the longitudinal spread of the hole 104) and / or the number and / or dimensions of the spacers 106 (particularly their lengths along the longitudinal spread of the hole 104). In this case, the length of the insertion element 105 is preferably equal to the depth of the hole 104, and in this embodiment, the sum of the length of the insertion element 105 and the length of the sealing means 115 that seals the hole 104 is approximately equal to the depth of the hole 104.

[0036] The spacer 106 can be rigid or flexible, and may be formed in particular as a printed circuit board or a flexible substrate. The electrical connector 114 of the solid actuator 103 can also be introduced into a through-opening (not shown in detail) formed in the spacer 106. As shown in Figure 3, the insertion element 105 is fixed to the inner wall of the hole 104 by adhesive means 113, i.e., adhesive. In this case, it is preferable that the adhesive means 113 be added through an access hole 107 that is fluidly connected to the hole 104.

[0037] In this embodiment, each solid actuator stack 103 is assigned an access hole 107 connected to a hole 104. In this embodiment, both the hole 104 and the access hole 107 are sealed at least fluidly by sealing means 115, for example, glass or steel closures or plugs. Particularly preferably, the plugs have substantially the same coefficient of thermal expansion (CTE). The solid actuator 103 can have any desired direction of operation. In this embodiment, there is a solid actuator 103 that enables operation in the direction normal to the optically effective surface 102. However, it is also possible to use a solid actuator 103 that operates parallel to the optically effective surface 102 or a solid actuator 103 that operates in any direction. The deflection of the solid actuator 103 causes deformation of at least a portion of the substrate 101 and, consequently, the optically effective surface 102. In addition to the holes 103, notches 111 are also present in the substrate 101 to counteract material stress. Furthermore, at least a portion, but preferably all, of the inner walls of the pores are covered with a protective layer 112 that absorbs light in the UV wavelength range.

[0038] From a process technology perspective, the insertion element 105 facilitates inserting the solid actuators 103 into the holes 104 and setting the position of each solid actuator / actuator stack 103 within the holes 104 to a predetermined position. Additionally, the holes 104 can compensate for mechanical misalignment of individual solid actuators 103, and therefore of the actuator stack. Furthermore, the insertion element 105 facilitates actuator replacement in the adaptive optical element 100.

[0039] Alternatively, the insertion element 105 may also be formed as a sleeve housing a solid actuator 103 or a solid actuator 103 and a spacer 106. Alternatively, the insertion element 105 may also be formed as a rail or spoke to which at least one solid actuator / solid actuator stack 103 and optionally at least one spacer 106 are attached. Additionally, the insertion element 105 may be formed from exactly one solid actuator 103 or exactly one actuator stack. The exemplary embodiment shown in Figure 3 preferably has a plurality of holes 104 extending into the substrate, to which the insertion element 105 is housed and fixed in at least some of the holes 104.

[0040] Figure 3 shows an exemplary second embodiment of an adaptive optical element 100 in the form of an adaptive mirror. A notable feature is that the access hole 107 is open. Nevertheless, in order to maintain a constant humidity level within the adaptive optical element 100, at least one medium opening, preferably multiple medium openings 108, are present to supply air, gas, or fluid to the hole. In this embodiment, the spacer 106 also has a through-opening (not shown in more detail) for guiding the medium flow along the hole 104. In the exemplary embodiment shown in Figure 3, the length of the insertion element 105 corresponds at least substantially to the depth of the hole. However, the hole 104 may optionally be sealed by a sealing means 115.

[0041] In the exemplary embodiments shown in Figures 2 and 3, at least one hole 104 extends parallel to the optically effective surface 102. Figure 4 shows an embodiment in which there are multiple holes 104, and the holes 104 penetrate the substrate 101 in a linear manner, forming an angle other than 180° with the optically effective surface 102. Insertion elements 105 (not shown in detail), each having at least one solid actuator 103, are housed in each hole 104. Furthermore, the holes 104 may also be designed tangentially to a point on the optically effective surface 102, and to penetrate linearly through a region of the mirror body 101. In this regard, it is advantageous if the point substantially corresponds to the center of the longitudinal spread of the hole 104.

[0042] An exemplary embodiment shown in Figure 5 illustrates an adaptive optical element 100 having a plurality of holes 104 that penetrate and are spaced apart from each other in at least a portion of the mirror substrate. Insertion elements 105 (not shown in detail) are housed in the holes 104 or at least some of the holes 104. The individual insertion elements 105 may all be formed similarly, or they may differ in the number and / or dimensions of the solid actuator stacks 103 and / or the number and / or dimensions of the spacers 106.

[0043] The exemplary embodiment shown in Figure 6 differs in that it has a first layer 109 having a plurality of first holes 104a in which the insertion elements 105 are housed, and a second layer 110 adjacent to the first layer 109 having a plurality of second holes 104b in which the insertion elements 105 are housed, and that the extending direction of the first holes 104a is offset from the extending direction of the second holes 104b, and in this embodiment is perpendicular to the second holes 104b. There may also be three or more layers on the substrate 101. In that case, the extending directions may correspond to each other or may differ from each other.

[0044] The adaptive optical element 100 in Figures 5 and 6 is illustrated in a highly simplified manner. The features shown in Figures 2, 3, and 4 are also applicable to the exemplary embodiments shown in Figures 5 and 6. [Explanation of Symbols]

[0045] 100 Adaptive Mirrors 101 circuit board 102 Optically Effective Surface 103 Solid Actuator 104 holes 104a 1st hole 104b 2nd hole 105 Insertion element 106 Spacer 107 Access Ports 108 Media opening 109 1st layer 110 2nd layer 111 Notch 112 Protective layer 113 Adhesion means 114 Electrical connector 115 sealing means 600 Projection Exposure System 601 Plasma light source 602 Collector Mirror 603 Field of View Faceted Mirror 604 Eye Facet Mirror 605 First Telescopic Mirror 606 Second Telescopic Mirror 607 Polarizing Mirror 620 Mask Stage 621 Masks 651 Mirror (Projection Lens) 652 Mirror (Projection Lens) 653 Mirror (Projection Lens) 654 Mirror (Projection Lens) 655 Mirror (Projection Lens) 656 Mirror (Projection Lens) 660 wafer stage 661 Coated substrate 700 DUV lithography system 701 DUV light source 702 DUV radiation / beam path 703 Beam shaping and illumination systems (DUV) 704 Photomask 705 Projection system 706 wafers 707 Lens element 708 Mirror 709 Optical axis

Claims

1. An adaptive optical element (100) of a microlithography projection exposure apparatus (600, 700), A substrate (101) and Optically effective surface (102) and At least one solid actuator (103) that bends or deforms the optically effective surface (102) at least partially, and An adaptive optical element (100) having, characterized in that there is at least one hole (104) penetrating at least a portion of the substrate (101), there is an insertion element (105) including at least one solid actuator (103), and the insertion element (105) is designed and housed in the hole (104) such that the at least one solid actuator (103) is positioned and fixed in a predetermined position within the hole (194).

2. The adaptive optical element (100) according to claim 1, wherein the insertion element (105) includes at least one spacer (106) connected to the at least one solid actuator (103).

3. The adaptive optical element (100) according to claim 1 or 2, wherein the insertion element (105) includes a plurality of solid actuators (103), and two adjacent solid actuators (103) are connected to each other by spacers (106).

4. An adaptive optical element (100) according to claim 2 or 3, characterized in that at least the individual spacers (106) are formed to be flexible.

5. An adaptive optical element (100) according to any one of claims 1 to 4, characterized in that the length of the insertion element (105) is equal to the depth of the hole (104).

6. An adaptive optical element (100) according to any one of claims 1 to 5, characterized in that the insertion element (105) is formed as a sleeve on which the at least one solid actuator (103) is disposed.

7. An adaptive optical element (100) according to any one of claims 1 to 5, wherein the insertion element (105) is formed as a rail to which the at least one solid actuator is attached.

8. An adaptive optical element (100) according to any one of claims 1 to 7, characterized in that the at least one hole (104) extends substantially parallel to the optically effective surface (102) in at least a portion of the substrate (101).

9. An adaptive optical element (100) according to any one of claims 1 to 8, characterized in that the at least one hole (104) extends tangentially with respect to the optically effective surface (102) in at least a portion of the substrate (101).

10. An adaptive optical element (100) according to any one of claims 1 to 9, characterized in that at least one access hole (107) is fluidly connected to at least one hole (104) for supplying adhesive means to the hole (104).

11. An adaptive optical element (100) according to any one of claims 1 to 10, characterized in that the holes (104, 107) are sealed in a liquid-tight and / or airtight manner.

12. An adaptive optical element (100) according to any one of claims 1 to 10, characterized in that a medium opening (108) fluid-connected to at least one hole (104) is present for supplying gas or fluid to the hole (104).

13. An adaptive optical element (100) according to any one of claims 1 to 12, characterized in that at least one hole (104) or at least one of the holes (104) is formed as a blind hole.

14. An adaptive optical element (100) according to any one of claims 1 to 12, characterized in that at least one hole (104) or at least one of the holes (104) is formed as a through hole penetrating the substrate (101).

15. An adaptive optical element (100) according to any one of claims 1 to 14, characterized in that a plurality of holes (104) are present, spaced apart from each other and penetrating at least a portion of the substrate (101), and an insertion element (105) including at least one solid actuator (103) is housed in each of the holes (104).

16. An adaptive optical element (100) according to any one of claims 1 to 15, characterized in that there is a first layer (109) having a plurality of first holes (104a) in which insertion elements (105) are housed, and a second layer (110) adjacent to the first layer (109) having a plurality of second holes (104b) in which insertion elements (105) are housed, and the extending direction of the first holes (104a) is offset from the extending direction of the second holes (104b).

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