Equipment for Peltier module, assembly and mask inspection

Abstract

To provide a Peltier module, an assembly and an apparatus for mask inspection.SOLUTION: A Peltier module according to the invention has a plurality of Peltier pellets (122), which is made of a semiconductor material and is arranged between a first plate (121) forming a hot side and a second plate (123) forming a cold side, wherein the first plate (121) and the second plate (123) are each made of a metallic material, and wherein a vacuum seal component (126) is provided on the second plate (123).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims priority from German patent application no. 102023201942.6, filed on March 3, 2023, the contents of which are also incorporated by reference into the present application.

[0002] The present invention relates to a Peltier module, an assembly, and an apparatus for mask inspection. [Background technology]

[0003] In practice, for example, in an optical system designed to operate in the EUV range and equipped with one or more image sensors, it is necessary to efficiently dissipate the heat generated by the image sensors during operation while at the same time avoiding damage to the vacuum present in the optical system. Known approaches involve the use of cooling channels through which a cooling fluid can flow in any case, but this entails limited cooling performance, potentially insufficient setting accuracy for the specified temperature setpoints, and complex handling of the necessary cooling fluid connections under the given vacuum conditions.

[0004] The use of Peltier modules, for example arranged as pellets between two ceramic plates, for active cooling of components or component parts, is also known in principle, with one of the ceramic plates forming the hot side of the Peltier module and the other forming the cold side. However, under vacuum (especially EUV) conditions, the use of such Peltier modules has proven problematic in terms of contamination aspects and can result in insufficient efficiency and cooling performance. However, since the performance of image sensors is largely determined by the operating temperature, for example in mask inspection application scenarios, insufficient cooling will impair the performance of the image sensor or the associated optical system, and maintaining proper operation while maintaining vacuum conditions is very difficult in practice.

[0005] Microlithography is used to manufacture finely structured components, e.g., in integrated circuits or LCDs. The microlithography process is carried out in what is called a projection exposure apparatus, which comprises an illumination device and a projection lens. The image of a mask (= reticle), illuminated by the illumination device, is then projected by the projection lens onto a substrate (e.g., a silicon wafer), which is coated with a photosensitive layer (photoresist) and placed in the image plane of the projection lens in order to transfer the mask structure onto the photosensitive coating of the substrate.

[0006] Unwanted defects on a mask can have a particularly detrimental effect in the lithography process if these defects can be reproduced with each exposure step, thus risking the entire output of a semiconductor component being unusable in a worst-case scenario. Therefore, it is very important to ensure that a mask has sufficient imaging capabilities before it can be used in mass production. Mask inspection tools are used to quickly, easily, and reliably test masks, preferably under conditions similar to those actually present in a projection exposure tool. A mask inspection tool includes an illumination system and a projection lens, which images the illuminated area of ​​the mask onto an image sensor device, such as a CCD camera. Summary of the Invention

[0007] Against the above background, it is an object of the present invention to provide a Peltier module, assembly, and apparatus for mask inspection that allows for efficient dissipation of heat generated during operation while at least partially avoiding the aforementioned problems.

[0008] This object is achieved according to the features of the independent claims.

[0009] According to one aspect, the present invention provides a method for manufacturing a semiconductor device comprising: - a plurality of Peltier pellets made from a semiconductor material and arranged between a first plate forming a hot side and a second plate forming a cold side, the first plate and the second plate are each made of a metallic material; a vacuum seal component is provided on the second plate; Regarding Peltier modules.

[0010] The invention is based on the idea of ​​using Peltier modules for actively cooling image sensors or camera chips, in particular for optical systems designed to operate in the EUV wavelength range with a corresponding vacuum, such as, inter alia, devices for mask inspection, for example by designing the Peltier module to be "metal-based" for this purpose (i.e. by making the plates forming the cold and hot sides of the Peltier module from a metallic material) and further by designing the cold side of the Peltier module or the corresponding plate directly as the "vacuum part" which allows sealing the (EUV) vacuum of the optical system which ultimately receives the image sensor.

[0011] By making the plates that form the hot and cold sides (which receive the Peltier pellet between them) from a metallic material, it is possible to improve the cooling performance (e.g., up to 20 W / cm 2 This allows for extremely high speeds (over 1000km / h) and also allows for direct machining for mounting purposes (especially for targeted adaptation to customer-specific application scenarios).

[0012] The design of the second plate forming the cold side as a "vacuum part" is realized according to the invention by using a suitable vacuum-compatible material (e.g., aluminum, Al) and by the fact that the vacuum seal components (i.e., preparation of the vacuum seal, e.g., by incorporating a groove for an O-ring seal) are already provided on the associated second plate forming the cold side. In an embodiment of the invention, the second plate already forms the mounting interface for the respective image sensor or image sensor carrier and for this purpose may be configured with, for example, one or more fastening holes for fastening the image sensor carrier.

[0013] The Peltier module according to the invention can also be used in embodiments, in particular in the sense of closed-loop temperature control, for example to achieve active cooling of an image sensor below ambient temperature.

[0014] According to one embodiment, the material of the second plate is ultra-high vacuum or 10 -5 The material is suitable for operation at sub-pascal partial pressures.

[0015] In an embodiment, the material of the second plate may be a material suitable for operation at a partial pressure of less than 10 Pascals, preferably less than 5 Pascals. -7 It may also be a material suitable for operation at sub-Pascal partial pressures. In particular, the material of the second plate may be, for example, an EUV-compatible aluminum (Al) and / or stainless steel alloy.

[0016] According to one embodiment, the second plate is designed as a mounting interface for an image sensor or an image sensor carrier.

[0017] According to one embodiment, the second plate has at least one fastening contour, in particular at least one fastening hole, for fastening the image sensor carrier.

[0018] Furthermore, the present invention further provides: a Peltier module having a plurality of Peltier pellets made from a semiconductor material and arranged between a first plate forming a hot side and a second plate forming a cold side, the first plate and the second plate each being made from a metallic material; an image sensor carrier and / or an image sensor fixed to the second plate; The present invention also relates to an assembly comprising:

[0019] According to one embodiment, a Peltier module is designed with the aforementioned features.

[0020] According to one embodiment, a heat dissipation block is disposed on the first plate for dissipating heat generated during hot side operation.

[0021] According to one embodiment, a vacuum seal between the vacuum present in the region of the image sensor and the ambient atmosphere present in the region of the hot side is provided by a second plate.

[0022] According to one embodiment, a closed loop control unit is also provided for controlling the temperature of the image sensor, in particular a temperature below ambient temperature can also be achieved.

[0023] The invention further relates to an apparatus for inspecting a mask, the mask being illuminated in a lithography process in a projection exposure apparatus for exposing a wafer, the apparatus comprising an illumination system, a projection lens and a sensor arrangement with at least one image sensor, wherein a Peltier module with the aforementioned characteristics is provided for cooling the at least one image sensor.

[0024] According to one embodiment, the mask is designed to operate in reflection at operating wavelengths below 30 nm.

[0025] Further configurations of the invention are evident from the description and the dependent claims.

[0026] The present invention will now be described in more detail based on preferred exemplary embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0027] [Figure 1] 1 shows a schematic diagram of a possible configuration of an assembly according to the invention with a Peltier module in principle. [Figure 2] 1 shows a schematic diagram of the structure of an apparatus for mask inspection which is possible in principle as a possible application scenario of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 1 shows, merely schematically, one possible configuration of an assembly 100 comprising a Peltier module according to the invention in one embodiment of the invention.

[0029] 1, the Peltier module according to the invention firstly comprises, in a manner known per se, a number of Peltier pellets 122 made of a semiconductor material (for example bismuth telluride, Bi2Te3) and arranged between a first plate 121 forming the hot side of the Peltier module and a second plate 123 forming the cold side of the Peltier module. According to the invention, the first plate 121 and the second plate 123 are made of a metallic material, in particular aluminium (Al).

[0030] "120" refers to a heat dissipation block mechanically coupled to the first plate 121 forming the hot side, through which heat generated during operation of the hot side is dissipated to the outside. The second plate 123 forming the cold side is, according to the invention, designed as a mounting interface for the image sensor carrier 124 and for this purpose has fixing holes 128 corresponding to appropriate positions in the illustrated embodiment. "125" refers to the image sensor supported by the image sensor carrier 124, or the camera chip that in certain application scenarios is located in the (EUV) vacuum of the optical system.

[0031] In the assembly according to the present invention, the second plate 123 providing the cold side of the Peltier module functions as a "vacuum part" where the necessary seal is achieved between the EUV vacuum present in the area of ​​the image sensor 125 and the ambient atmosphere present on the hot side. Additionally, the second plate 123 providing the cold side of the Peltier module also functions as a mounting interface to which the image sensor 125 or the associated image sensor carrier 124 is directly mechanically fastened (e.g., using fastening screws and / or adhesive).

[0032] As a result, the image sensor 125 is thus actively cooled during operation of the associated optical system, while avoiding damaging (EUV) vacuums present in the optical system or on the side of the image sensor.

[0033] The optical system is in particular an apparatus for mask inspection, the configuration of which, in principle, is explained in the following text with reference to the merely schematic diagram of FIG.

[0034] 2, an apparatus 200 for mask inspection comprises an illumination system 210 and a projection lens 220, where light from a light source (not shown in FIG. 2) enters the illumination system 210 and impinges on a mask 230 arranged in the object plane of the projection lens 220, and the illuminated area of ​​the mask 230 is imaged by the projection lens onto a sensor device 240. The sensor device 240 may in particular comprise an image sensor provided according to the invention with a Peltier module for heat dissipation or active closed-loop temperature control, as described above with reference to FIG.

[0035] To predict the imaging result that will be obtained on the mask when a lithographic process is performed in a projection exposure apparatus, first a measurement of the intensity distribution that is obtained on the mask in an apparatus for mask inspection or with a sensor arrangement according to Fig. 2 is made, whereby the same wavelength is preferably used in the mask inspection system that is also used during the lithographic process in the projection exposure apparatus.

[0036] While the present invention has been described based on particular embodiments, numerous variations and alternative embodiments will be apparent to those skilled in the art, for example, by combining and / or substituting features of the particular embodiments. Accordingly, it will be apparent to those skilled in the art that such variations and alternative embodiments are also encompassed by the present invention, the scope of which is limited only in the sense of the appended claims and their equivalents. [Explanation of symbols]

[0037] 120 Heat dissipation block 121 First Plate 122 Peltier pellets 123 Second Plate 124 Image Sensor Carrier 125 Image sensor or camera chip 128 fixing hole 200 Mask inspection equipment 210 Lighting System 220 projection lens 230 Mask 240 Sensor Device

Claims

1. a plurality of Peltier pellets (122) made of a semiconductor material and arranged between a first plate (121) forming a hot side and a second plate (123) forming a cold side; the first plate (121) and the second plate (123) are each made of a metallic material; a vacuum seal component (126) is provided on said second plate (123); characterised in that the second plate (123) is designed as a mounting interface for an image sensor (125) or an image sensor carrier (124), Peltier module.

2. The material of the second plate (123) is 10 -5 10. A Peltier module according to claim 1, characterized in that the material is suitable for operation at partial pressures below pascals.

3. 2. A Peltier module according to claim 1, characterized in that the second plate (123) has at least one fixing contour for fixing the image sensor carrier (124).

4. 2. The Peltier module according to claim 1, characterized in that the second plate (123) has at least one fixing hole (128) for fixing the image sensor carrier (124).

5. a Peltier module made of a semiconductor material and having a plurality of Peltier pellets (122) arranged between a first plate (121) forming a hot side and a second plate (123) forming a cold side, the first plate (121) and the second plate (123) each being made of a metallic material; an image sensor carrier (124) and / or an image sensor (125) fixed to the second plate (123); Equipped with a vacuum seal between the vacuum present in the region of the image sensor (125) and the ambient atmosphere present in the region of the hot side is provided by the second plate (123); An assembly (100).

6. Assembly according to claim 5, characterized in that the Peltier module is designed according to claim 1 or 2.

7. 6. The assembly according to claim 5, characterized in that a heat dissipation block (120) is arranged on the first plate (121) for dissipating heat generated on the hot side during operation.

8. 6. The assembly according to claim 5, further comprising a closed-loop control unit for controlling the temperature of the image sensor (125).

9. 1. An apparatus for inspecting a mask, the mask (230) being illuminated in a lithography process in a projection exposure apparatus for exposing a wafer, the apparatus (200) comprising an illumination system (210), a projection lens (220) and a sensor device with at least one image sensor (125), the Peltier module according to claim 1 being provided for cooling the at least one image sensor (125).

10. 10. The apparatus of claim 9, wherein the mask (230) is designed for reflective operation at operating wavelengths below 30 nm.

Images