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KR-20260065935-A - Method for fixing a MEMS micromirror unit and a MEMS micromirror unit

KR20260065935AKR 20260065935 AKR20260065935 AKR 20260065935AKR-20260065935-A

Abstract

The present invention relates to a method for fixing a MEMS micromirror unit (100) within an upper assembly (200) having at least one receptacle (210) for a MEMS micromirror unit (110), such as used in a projection exposure device (1) for photolithography, for example. The present invention also relates to a MEMS micromirror unit (100) having a configuration advantageous for this purpose. The present invention comprises: a) introducing the MEMS micromirror unit (100) into the receptacle (210); b) aligning the MEMS micromirror unit (100) with respect to the receptacle (210); c) applying an axial tensile force greater than a subsequent preloading force to an interface element (120) of the MEMS micromirror unit, thereby causing longitudinal extension of the interface element (120); and d) fixing a preloading element (300) at a predefined longitudinal position on the interface element (120). and e) a step of reducing and removing axial tensile force. The preloading element (300) does not come into contact with the receptacle (210) prior to the reduction of the axial tensile force, thereby preventing the complete failure of longitudinal extension of the interface element (120), and as a result, the preloading force is maintained on the interface element (120), and said preloading force can be used to fix the MEMS micromirror unit (100) within the receptacle (210).

Inventors

  • 하웁 마르쿠스
  • 비크 헤어만

Assignees

  • 칼 짜이스 에스엠테 게엠베하

Dates

Publication Date
20260511
Application Date
20240906
Priority Date
20230915

Claims (14)

  1. A method for fixing a MEMS micromirror unit (100) within a higher assembly (200) having at least one receptacle (210) for the MEMS micromirror unit (100), wherein the MEMS micromirror unit (110) comprises a MEMS mirror array structure (110) and an axially elongated interface element (120), wherein the interface element has a lateral range smaller than that of the MEMS mirror array structure (100) such that the MEMS mirror array structure (110) protrudes laterally beyond the interface element (120), and a preloading element (300) is axially preloaded between the MEMS mirror array structure (110) and the preloading element (300) by means of a preloading element (300) fixed at a predetermined longitudinal position while the interface element (120) is inserted into the receptacle (210), and thereby fixable to the interface element (120) at a predetermined longitudinal position, and thereby the MEMS In a method in which a micromirror unit (100) is fixed within a receptacle (210), a) a step of introducing a MEMS micromirror unit (100) into a receptacle (210); b) A step of aligning the MEMS micromirror unit (100) with respect to the receptacle (210); c) a step of applying an axial tensile force greater than the subsequent preloading force to the interface element (120); d) fixing a preloading element (300) at a predefined longitudinal position on an interface element (120); and e) A method characterized by including a step of reducing and eliminating axial tensile force.
  2. In paragraph 1, A method characterized in that, to perform the method, the MEMS micromirror unit (100) operates only at the interface element (120) in an end region spaced apart from the MEMS mirror array structure (110).
  3. In paragraph 1 or 2, A method characterized in that, when applying an axial tensile force (91) and to maintain preloading, an axial spring element (130) integrated within an interface element (120) between a MEMS mirror array structure (110) and a predefined longitudinal position (125) is tensile with a predefined spring stiffness.
  4. In paragraph 3, A method for applying an axial tensile force (91), which involves taking action adjacent to a spring element (130) and/or a preloading element (300) being fixed at a predefined longitudinal position (125) adjacent to the spring element (130).
  5. In any one of paragraphs 1 through 4, A method characterized by having no contact between the preloading element (300) and the receptacle (210) when fixing the preloading element (300).
  6. In any one of paragraphs 1 through 5, A method characterized by the bayonet capture portion (121) or screw joint being operated to secure a preloading element (300) at a predefined longitudinal position (125) on an interface element (120).
  7. In any one of paragraphs 1 through 6, A method characterized in that, to define an angular orientation around the longitudinal axis of an interface element (120) and/or a position with respect to this longitudinal axis, a MEMS micromirror unit (110) engages with a suitable tooth portion (213), preferably a Hirt tooth portion (313), in a receptacle (310).
  8. In any one of paragraphs 1 through 7, A method characterized by providing a compensation part to define the axial position of a MEMS mirror array structure (110) relative to a receptacle (210) and/or to adjust the preloading force between the MEMS mirror array structure (110) and the receptacle (210) and/or between the receptacle (210) and the preloading element (300).
  9. In any one of paragraphs 1 through 8, A method characterized by the ring-shaped seal (330) being arranged between the MEMS micromirror unit (100) and the receptacle (210), wherein the seal is pressed by preloading between the MEMS micromirror unit (100) and the receptacle (210).
  10. In any one of paragraphs 1 through 9, A method characterized in that the step of introducing a MEMS micromirror unit (100) into a receptacle (210) is performed by a tool (400) that can be connected to the MEMS micromirror unit (100) by interlocking in a manner that, in an initial state, can be guided through the receptacle (210) and connected to the end of an interface element (120) spaced apart from the MEMS mirror array structure (110).
  11. A MEMS micromirror unit (100) for fixing within an upper assembly (200) having at least one receptacle (210) for the MEMS micromirror unit (100), wherein the MEMS micromirror unit (100) comprises a MEMS mirror array structure (110) that protrudes laterally beyond an elongated interface element (120), A MEMS micromirror unit characterized in that, between a MEMS mirror array structure (110) and a predefined longitudinal position (125), an axial spring element (130) is integrated within an interface element (120) having a predefined spring stiffness, and the interface element (120) is designed to fix a preloading element (300) at a predefined longitudinal position so that the interface element (120) is axially preloaded between the MEMS mirror array structure (110) and the preloading element (300) while inserted into a receptacle (210) and while the preloading element (300) is fixed at a predefined longitudinal position, and in this manner, the MEMS micromirror unit (100) is fixed within the receptacle (210).
  12. In Paragraph 11, A MEMS micromirror unit characterized by having a bayonet capture portion (121) or a screw joint provided to secure a preloading element (300) at a predefined longitudinal position (125) on an interface element (120).
  13. In Article 11 or Article 12, A MEMS micromirror unit (100) is characterized by having a tooth portion (213), preferably a Hirt tooth portion (313), for defining an angular orientation and/or position within a receptacle (210).
  14. In any one of paragraphs 11 through 13, A MEMS micromirror unit characterized by having a ring-shaped seal between a MEMS micromirror unit (100) and a receptacle (210), wherein the seal is pressed by preloading between the MEMS micromirror unit (100) and the receptacle (210).

Description

Method for fixing a MEMS micromirror unit and a MEMS micromirror unit This patent application claims priority to German patent application DE 10 2023 208 979.3 filed on September 15, 2025, by reference, the contents of which are incorporated herein in their entirety (“Incorporated by reference”). The present invention relates to a method for fixing a MEMS micromirror unit to a superordinate assembly having at least one receptacle for the MEMS micromirror unit, such as that used in semiconductor technology devices. The present invention further relates to a MEMS micromirror unit advantageously configured to carry out the method. In the prior art, a device for semiconductor technology is understood to be a device used for manufacturing or testing microstructured component parts or components required for this purpose. An example of such a device is a photolithographic projection exposure device. Photolithography is used to manufacture microstructured components, such as integrated circuits, for example. The projection exposure device used in the process includes an illumination system and a projection system. An image of a mask (also referred to as a reticle) illuminated by the illumination system is projected onto a substrate coated with a photosensitive layer, for example, a silicon wafer, to reduce the size of the image, and is aligned within the image plane of the projection system using the projection system to transfer the mask structure to the photosensitive coating of the substrate. Generally, for a projection lithography device designed for an illumination system, particularly for the EUV range, i.e., exposure wavelengths of 5 nm to 30 nm, two facet mirrors are arranged in the beam path between the actual exposure radiation source and the mask to be illuminated, and the mirrors allow for the homogenization of radiation in a manner essentially corresponding to the principle of a fly's eye condenser. The facet mirror closer to the beam path of the exposure radiation source is often the so-called field facet mirror, and the other facet mirror is the so-called pupil facet mirror. It is known that, in order to enable the generation of different intensity and/or incident angle distributions during illumination of a mask, at least one of the two facet mirrors—particularly the facet of the field facet mirror—is formed from one or more micromirrors that are individually electromechanically pivotable. The same is disclosed, for example, correspondingly in WO 2012/130768 A2. To enable the achievement of individual micromirrors of small size, it is a known practice to design a group of micromirrors in the form of a MEMS mirror array, that is, a mirror array manufactured by a microelectromechanical system (MEMS). In a MEMS mirror array, a plurality of small mirror elements are each mounted so as to be individually movable relative to a common base. For each mirror element, at least one actuator is provided, enabling the mirror element to be adjusted according to a predefined degree of freedom. The mirror elements can frequently pivot around two axes extending perpendicularly to each other and parallel to the base, and in this case, sufficient actuators are subsequently provided to enable the mirror elements to pivot precisely around these axes independently of each other. For each individual mirror element, a sensor is also provided, which can enable the position of the mirror element to be determined relative to the base, so that the alignment of the mirror can be monitored. A particularly advantageous embodiment for the mirrors of a MEMS mirror array is described in DE 10 2015 204 874 A1. A method for manufacturing a micromirror or MEMS mirror array comprising a plurality of such micromirrors is disclosed in DE 10 2015 220 018 A1, with further details regarding possible configurations of the micromirrors. To form a facet mirror for a projection exposure device, a plurality of MEMS mirror arrays are fixed to an upper assembly in a dense planar grid array. For this purpose, the MEMS mirror array is designed as a MEMS micromirror unit, which, in addition to the actual MEMS mirror array, also has an interface element, and the unit can be fixed to the upper assembly by means of this interface. In order for the MEMS mirror array to be arranged at small distances from each other for the stated purpose of use and to have the precise positioning and alignment required in the inserted and fixed state within the assembly, individual mirror elements of the MEMS micromirror unit need to be positioned and aligned with high precision with respect to their interface elements. Simultaneously, the insertion, alignment, and fixation of the MEMS micromirror unit within the upper assembly must be performed in such a manner that the sensitive microelectromechanical system is not damaged, which generally means that the microelectromechanical system must not be touched during mounting. Furthermore, once alignment is performed, it must