Reticle holding system and method of providing a reticle holding system for viewing a reticle

Abstract

A reticle holding system and a method of providing a reticle holding system for viewing a reticle, the reticle holding system comprising an inner cassette and an outer cassette. The inner cassette is configured to receive a reticle having a first identifying feature, the inner cassette comprising: an inner base having a reticle receiving area surrounded by a peripheral area, the reticle receiving area defining a first viewing area correspondingly arranged to allow viewing of the first identifying feature; and an inner cover configured to engage with the peripheral area of the inner base thereby defining an interior for receiving the reticle. The outer cassette is configured to receive the inner base and comprises: an outer base having a second viewing area defined thereon, wherein the second viewing area is viewably aligned with the first viewing area when the outer base receives the inner cassette; and an outer cover configured to engage with the outer base and cover the inner cassette.

Description

[0001] This application is a divisional application of application number 201980005342.3. The original application was entitled "Photomask Holding System" and the original application was filed on October 28, 2019. Technical Field

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 751,736, filed October 29, 2018, which is incorporated herein by reference and forms part of the specification.

[0003] This disclosure relates to containers for storing, conveying, transporting and handling fragile objects such as photomasks and wafers, and more particularly to holding systems for storing, conveying, transporting and holding photomasks. Background Technology

[0004] In the semiconductor industry, due to the increasing requirements for the load accuracy of photomask holders, photomask holders have also been developed to enhance protection against potential environmental hazards.

[0005] For example, new-generation mask holders sometimes have a dual-box structure, comprising an inner box for housing the mask and an outer box for housing the inner box. During transport, the mask may be housed within the inner box. To perform the photolithography process, the outer box can be opened to allow the inner box to be removed. Then, upon arrival at a designated location inside the exposure equipment, the inner box can be opened to use the mask for subsequent exposure processes. Summary of the Invention

[0006] According to one embodiment, one aspect of this disclosure provides a photomask holding system including an inner box and an outer box. The inner box is configured to receive a photomask having a first identification feature, the inner box including: an inner base having a photomask receiving area substantially located at a geometric center and surrounded by a peripheral region, wherein the inner base has a first observation area defined within the photomask receiving area, the first observation area being correspondingly arranged to allow observation of the first identification feature; and an inner cover configured to engage with the peripheral region of the inner base to define an interior for receiving the photomask. The outer box is configured to receive the inner base, the outer box including: an outer base defining a second observation area thereon, wherein, when the outer box receives the inner box, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box.

[0007] According to one embodiment, one aspect of this disclosure provides a photomask holding system including an inner box and an outer box. The inner box is configured to receive a photomask adjacent to a pellicle and having a first identification feature. The inner box includes: an inner base having a photomask receiving area substantially at its geometric center and surrounded by a peripheral region; and an inner cover configured to sealably engage with the peripheral region of the inner base, thereby defining an interior for receiving the photomask. The inner base includes internal optical components hermetically embedded in the photomask receiving area to allow observation of the first identification feature and a portion of the pellicle. The outer box is configured to receive the inner base and includes: an outer base including external optical components, wherein when the outer base receives the inner box, the external optical components are observably aligned with the internal optical components, and a second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box. Attached Figure Description

[0008] To provide a more detailed understanding of the features described above, reference to the embodiments can offer a more specific description of the present case as summarized above. Some embodiments are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only typical embodiments of the present case and are therefore not intended to limit the scope of the present case, as other equivalent embodiments may be recognized.

[0009] Figure 1 A schematic cross-sectional view of a photomask holding system according to some embodiments of the present disclosure is shown;

[0010] Figure 2 A schematic top view of a photomask holding system according to some embodiments of the present disclosure is shown;

[0011] Figure 3 An exploded view of a photomask holding system according to some embodiments of the present disclosure is shown;

[0012] Figure 4 A cross-sectional view of a photomask holding system according to some embodiments of the present disclosure is shown;

[0013] Figure 5 A cross-sectional view of a photomask holding system according to some embodiments of the present disclosure is shown; and

[0014] Figure 6 A top view of a photomask holding system according to some embodiments of the present disclosure is shown.

[0015] However, it should be noted that the accompanying drawings only illustrate exemplary embodiments of the present disclosure and should therefore not be considered as limiting its scope, as the present disclosure may allow for other equivalent embodiments.

[0016] It should be noted that these figures are intended to illustrate the general characteristics of the methods, structures, and / or materials used in some exemplary embodiments and to supplement the written description provided below. However, these figures are not drawn to scale and may not accurately reflect the precise structural or performance characteristics of any given embodiment, and should not be construed as defining or limiting the range of values ​​or characteristics covered by the exemplary embodiments. For example, the relative thickness and location of layers, regions, and / or structural elements may be reduced or enlarged for clarity. The use of similar or identical reference numerals in the various figures is intended to indicate the presence of similar or identical elements or features.

[0017] Explanation of reference numerals in the attached figures:

[0018]

[0019] Detailed Implementation

[0020] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention.

[0021] This disclosure will now be described more fully below with reference to the accompanying drawings, in which exemplary embodiments of the disclosure are illustrated. However, this disclosure may be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. Throughout the document, similar reference numerals refer to similar elements.

[0022] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. Furthermore, when used herein, “comprising” and / or “including” or “including” or “having” and / or “having,” integers, steps, operations, components, and / or components, but does not exclude the presence or addition of one or more other features, regions, integers, steps, operations, components, components, and / or groups thereof.

[0023] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Furthermore, unless expressly defined herein, terms such as those defined in a general dictionary shall be interpreted as having the same meaning as they have in the relevant art and in the content of this disclosure, and shall not be interpreted as having an idealized or overly formal meaning.

[0024] The following will combine Figures 1 to 6Exemplary embodiments are described below. Detailed description of this disclosure will be given with reference to the accompanying drawings, in which the elements depicted are not necessarily shown to scale. Identical or similar elements will be given the same or similar reference numerals or similar technical terms.

[0025] Figure 1 A schematic cross-sectional view of a photomask holding system according to some embodiments of the present disclosure is shown. For the sake of simplicity and clarity, some details / sub-components of the exemplary system are not explicitly labeled / shown in this figure.

[0026] Reference Figure 1 An exemplary photomask holding system 100 includes an outer casing 1 and an inner casing 2. The inner casing 2 is configured to be received by the outer casing 1. The inner casing 2 is configured to receive a photomask (also called a photomask). In the illustrated embodiment, the inner casing 2 includes an inner base 22 that defines a photomask receiving area 22a. The photomask receiving area 22a is surrounded by a peripheral region 22b. The inner casing 2 also includes an inner cover 21 configured to engage with the peripheral region 22b of the inner base 22, thereby cooperatively forming an internal space to accommodate the photomask R1 when closed. To provide thorough protection for sensitive and fragile contents, in some embodiments, the inner cover 21 and the inner base 22 have electromagnetic interference (EMI) shielding properties. Suitable materials for providing EMI shielding capabilities may include conductive materials such as metals. In some embodiments, a metallic coating (e.g., copper or gold) may be provided on the surface of the inner casing 2. In some embodiments, both the inner cover 21 and the inner base 22 are made of a metallic material, such as aluminum.

[0027] Reference Figure 1 An exemplary outer box 1 is configured to receive an inner box 2. In the illustrated embodiment, the outer box 1 includes an outer base 12 configured to receive an inner base 22 and an outer cover 11. The outer cover is configured to engage with the outer base 12 (and cover the inner box 2). The outer base 12 may have electrostatic dissipation properties. In some embodiments, the outer box 1 may comprise a polymer material mixed with conductive fibers. For example, in some embodiments, one or both of the outer cover 11 and the outer base 12 are made of a resin material embedded with carbon fibers.

[0028] In some embodiments, the inner cover 21 is configured to establish a sealing engagement with the peripheral region 22b of the inner base 22. In some embodiments, the inner cover 21 is configured to establish a pressing engagement with the inner base 22. The pressing engagement is created by pressure from the outer cover 11 when the outer base 12 and the outer cover 11 are closed. In some embodiments, the pressing engagement between the inner cover 21 and the inner base 22 can be formed through an interface between substantially planar metals. Typically, the pressing engagement establishes a sealing closure that prevents dust and moisture from entering the interior space through the contact interface between the upper and lower components of the inner housing 2. In some embodiments, one or both of the inner cover 21 and the inner base 22 may be provided with additional sealing elements (e.g., sealing gaskets or O-rings) at the respective engagement interface areas to further enhance the ability to block environmental contamination.

[0029] Reference Figure 1 The exemplary system has a first observation area Z defined in a photomask accommodating area 22a of an inner substrate 22. l1 This allows observation of the photomask R1. In the illustrated embodiment, the inner base 22 includes a first observation area Z. l1 An internal optical component 221 is included. In some embodiments, the internal optical component 221 may be made of a material that allows infrared, visible, or ultraviolet signals to pass through. Suitable materials for the internal optical component 221 may include glass (e.g., quartz glass), acrylic, transparent plastic, or similar materials. In the illustrated embodiment, the internal optical component 221 may include a piece of quartz glass embedded in the inner base 22 (in the photomask receiving area 22a).

[0030] In this embodiment, the first observation region Z l1 Accordingly, it is designed to allow observation of a first identification feature (e.g., a one-dimensional or two-dimensional barcode) upon receiving a photomask R1 (not explicitly shown in the schematic diagram). In some embodiments, the first identification feature of the photomask R1 is formed facing the first observation area Z. 11 On the surface of the window in the middle.

[0031] The outer base 12 has a second observation area Z 12 Second observation zone Z 12 Arranged to be the first observation area Z of inner box 1 l1 Observable alignment. This allows alignment to be achieved by passing through the second observation zone Z. 12 and the first observation zone Z l1Optical scanning is used to confirm the photomask R1 (such as the state and first identifier of photomask R1) held in the photomask holding system 100. Therefore, the frequency of cell opening can be reduced during semiconductor manufacturing, and the possibility of exposing sensitive precision workpieces to potentially hazardous environmental factors can be minimized.

[0032] In the illustrated embodiment, the outer base 12 has an embedded portion in the second observation area Z. 12 The external optical component 121 is provided. The external optical component 121 may be made of a material that allows infrared, visible, or ultraviolet signals to pass through. Suitable materials for the external optical component 121 may include glass (e.g., quartz glass), acrylic, transparent plastic, or similar materials. In some embodiments, the transmittance value of the external optical component 121 is greater than 80% for optical signals in one or more of the aforementioned spectral ranges. In some embodiments, depending on specific application requirements, the optical components (e.g., external and / or internal optical components) may include concave / convex surfaces.

[0033] In some embodiments, the internal optical component 221 has a lower reflectivity value than the external optical component 121 in the wavelength range between 600 nm and 950 nm. The wavelength range corresponding to the optical component can be in the range of approximately 630 nm to 930 nm. In some embodiments, the reflectivity value of the external optical component 121 relative to the above wavelength range can be less than 15%. In some embodiments, the reflectivity value of the internal optical component 221 relative to the above wavelength range can be less than 0.5%. In some embodiments, the internal optical component 221 may further have an anti-reflection layer. In some embodiments, the internal optical component 221 may further be provided with a layer having EMI shielding properties.

[0034] In some embodiments, the internal optical component 221 can be hermetically mounted in the first observation area Z. l1 For example, the construction of the internal optical component 221 may include a sealing member (e.g., an O-ring) surrounding the light-transmitting component. Typically, the construction of the internal optical component 221 provides a sealing closure that adequately prevents dust and moisture from entering the internal space through the structural interface between the optical component and the inner base. In some embodiments, the optical component 221 may be constructed to achieve an airtight seal.

[0035] In some embodiments with stringent dustproof requirements, the second observation area Z of the outer base 12 The external optical component 121 can also have the same sealing mechanism. However, in applications where internal sealing alone is sufficient, the external optical component 121 can be constructed without a sealing mechanism, thereby reducing structural complexity, weight, and cost.

[0036] Figure 2 A top view of a photomask holding system according to some embodiments of the present disclosure is shown. For the sake of simplicity and clarity, some details / sub-components of the exemplary device are not explicitly labeled / shown in this figure. For example, the inner cover and outer cover are not shown.

[0037] In the illustrated embodiment, in a top view, the photomask R1, inner base 22, and outer base 12 have a generally rectangular planar profile (or top view profile). As shown, the photomask accommodating area 22a of the exemplary inner base 22 is formed approximately at its geometric center.

[0038] Figure 3 An exploded view of a photomask holding system according to some embodiments of the present disclosure is shown. For the sake of simplicity and clarity, some details / sub-components of the exemplary system are not explicitly labeled in this figure.

[0039] An exemplary photomask holding system 300 includes an outer casing 31 and an inner casing 32. The inner casing 32 is configured to be received by the outer casing 31. The inner casing 32 is configured to receive a photomask. In the illustrated embodiment, the inner casing 322 includes an inner base 322 and an inner cover 321. The inner base 322 defines a photomask receiving area 322a. The photomask receiving area 322a is surrounded by a peripheral region 322b. The inner cover 321 is configured to engage with the peripheral region 322b of the inner base 322, thereby cooperatively forming an internal space to accommodate the photomask R3 when closed.

[0040] An exemplary outer box 31 is configured to receive an inner box 32. In the illustrated embodiment, the outer box 31 includes an outer base 312 configured to receive an inner base 322 and an outer cover 311. The outer cover 311 is configured to engage with the outer base 312 and cover the inner box 32.

[0041] In some embodiments, the inner cover 321 is configured to form a sealing engagement with the peripheral region 322b of the inner base 322. For example, the inner cover 321 may be configured to be pressed by the outer cover 311 when closed between the outer base 312 and the outer cover 311.

[0042] In some embodiments, the inner cover 321 and the inner base 322 have electromagnetic interference (EMI) shielding properties, thereby reducing adverse effects on the photomask R3. In some embodiments, suitable materials and construction of the inner cover 321 and the inner base 322 may be similar to those in the foregoing embodiments. In the illustrated embodiment, both the inner cover 321 and the inner base 322 are made of aluminum, for example, using computer numerical control (CNC) machining technology.

[0043] As shown in the figure, a first observation area Z31 is defined in the photomask accommodating area 322a of the inner base 322 to enable observation of the photomask R3. In the illustrated embodiment, the inner base 322 includes two internal optical components 3221, 3222 embedded in the first observation area Z31.

[0044] In the illustrated embodiment, the inner base 322 includes a third identification feature I3 on ​​its bottom side. In some embodiments, the third identification feature I3 may include a two-dimensional barcode such as a quick response code (QR code). In some embodiments, the third identification feature I3 may be a visual graphic feature indicating the orientation of the inner box 32 relative to the outer box 31. For example, the third identification feature I3 may include an asymmetrical pattern.

[0045] The outer base 312 has a second observation area Z defined thereon. 32 When the outer base 312 receives the inner box 31, the second observation area Z 32 The first observation area Z of the inner box 31 can be observably aligned. 31 Thus, it can be easily achieved by traversing the second observation zone Z. 32 and the first observation zone Z 31 The scanning confirms information about the photomask R3 held in the photomask holding system 300 (e.g., the condition or state of the photomask R3 and its first identification feature I1), thereby reducing the number of times the outer casing 32 must be opened. A scanner S (such as...) can be provided. Figure 4 (As shown) the third identification feature I3 of the inner box 32 is scanned by the external optical component 3121 to identify the orientation of the inner box 32. Subsequent adjustments can be made to fine-tune the orientation.

[0046] In the illustrated embodiment, the outer base 312 has an external optical component 3121 embedded in the second observation area Z. 32 The external optical component 3121 may be made of a material that allows infrared, visible, or ultraviolet signals to pass through. In some embodiments, the transmittance of the external optical component 3121 is greater than 80%. The material of the external optical component 3121 may be comparable to that of the external optical components described in the previous embodiments.

[0047] In some embodiments, the internal optical component 3221 has a lower reflectance value than the external optical component 3121 in a wavelength range between 600 nm and 950 nm. The wavelength range corresponding to the optical component can be in the range of approximately 630 nm to 930 nm. In some embodiments, the reflectance value of the external optical component 3121 relative to the above wavelength range can be less than 15%. In some embodiments, the reflectance value of the internal optical component 3221 relative to the above wavelength range can be less than 0.5%. In some embodiments, the internal optical component 3221 may further have an anti-reflection layer. The low reflectance value of the internal optical component 3221 can be attributed to the anti-reflection layer.

[0048] In some embodiments, the two internal optical components 3221, 3222 may be hermetically mounted in the first observation area Z31. In some embodiments, the two internal optical components 3221, 3222 may be made of a material that allows infrared, visible, or ultraviolet signals to pass through. In some embodiments, suitable materials for the two internal optical components 3221, 3222 may be equivalent to the materials described in the foregoing embodiments. In some embodiments, the external optical component 3121 may be hermetically mounted in the second observation area Z31. 32 middle.

[0049] Figure 4 and Figure 5 Cross-sectional views and regional cross-sectional views of a photomask holding system according to some embodiments of the present disclosure are shown respectively. For the sake of simplicity and clarity, some details / sub-components of the exemplary system are not explicitly labeled in the figures. In some embodiments, Figure 5 It can be a cut from Figure 4 The cross-sectional view of the region within the dashed box D shown in the figure.

[0050] Figure 4 The image shows a photomask R4 received in a photomask receiving area 422a on an inner base 422. In the illustrated embodiment, a peripheral region 422b of the inner base 422 is press-fitted with an inner cover 421.

[0051] In the illustrated embodiment, the photomask R4 includes a first identification feature I1 (e.g., a two-dimensional barcode), a protective film P disposed near the first identification feature I1, and a protective film frame PF disposed between the photomask R4 and the protective film P. A second identification feature I2 (e.g., ...) Figure 5 The first identification feature I1 (as shown) is disposed on the protective film frame PF. A scanner S can be provided to read the first identification feature I1 through an external optical component 4121. A portion of the protective film P and the protective film frame PF can be observed / inspected (e.g., by an interferometer) through the external optical component 4121 and the internal optical component 4221.

[0052] Reference Figure 5In the illustrated embodiment, the first observation region Z 51 The arrangement is accordingly designed to allow observation of the first identification feature I1 of the photomask R5, the second identification feature I2 of the protective film frame PF, a portion of the protective film P, and a portion of the protective film frame PF when receiving the photomask R5.

[0053] The photomask accommodating region 522a of the inner base 522 has a thickness T522a, which is smaller than the thickness T522b of the peripheral region 522b. The photomask accommodating region 522a includes a stepped profile 522s in its cross-section. In the illustrated figures, the angle of the stepped profile 522s is approximately right-angled; in practical applications, the stepped profile can be adjusted according to specific design requirements. In the illustrated embodiment, the periphery of the photomask R5 is supported above the stepped profile 522s, while the protective film P and the protective film frame PF are projectively surrounded by the stepped profile 522s (e.g., in a top view, the stepped profile 522s surrounds the protective film frame PF). In some embodiments, the stepped profile 522s may projectively overlap with the external optical component 5121.

[0054] In some embodiments, the status (e.g., presence of photomask R5, its serial number, its orientation) of photomask R5 can be detected by scanner S through external optical components 5121 and multiple internal optical components (e.g., component 5221 visible from the current cross-sectional view) without opening the photomask holding system. A third identification feature I3 of inner box 522 can be scanned to identify its serial number and status.

[0055] Figure 6 A top view of a photomask holding system according to some embodiments of the present disclosure is shown. For the sake of simplicity and clarity, some details / sub-components of the exemplary system are not explicitly labeled / shown in this figure. For example, in Figure 6 The inner and outer covers are not shown.

[0056] In the illustrated embodiment, one of the two internal optical components 6221 and 6222 has a larger planar area than the other of the two internal optical components 6221 and 6222. For example, from the illustrated top view, internal optical component 6221 has a larger area than internal optical component 6222.

[0057] In the illustrated embodiment, the internal optical component 6221 is designed to have a larger planar area to allow simultaneous optical channel communication to the protective film P, the second identification feature I2 of the protective film frame PF, and a portion of the protective film frame PF. Conversely, the internal optical component 6222 has a smaller planar area to allow observation of the first identification feature I1. Meanwhile, the external optical component 6121 is observably aligned with the two internal optical components 6221 and 6222, thereby enabling observation of the protective film P, the second identification feature I2 of the protective film frame PF, a portion of the protective film frame PF, and the first identification feature I1.

[0058] In the illustrated embodiment, the external optical component 6121 is configured to allow observation of the third identification feature I3. Thus, the status of elements such as the photomask R6, the protective film P, the protective film frame PF, and information about the identification features I1, I2, and I3 can be confirmed by observing the external optical component 6121, thereby reducing the number of times the outer casing needs to be opened.

[0059] In some embodiments, the external optical components may projectively overlap with the two internal optical components. In the illustrated embodiment, the two internal optical components 6221, 6222 are arranged to completely overlap (e.g., projectively cover) the external optical component 6121. In such an embodiment, the planar area of ​​the external optical component is equal to or greater than that of the internal optical components 6221, 6222. For example, in the illustrated top view, the planar area of ​​the external optical component 6121 is greater than the internal area of ​​the two internal optical components. In some embodiments, certain portions of the two internal optical components may not overlap with the external optical components. In such embodiments, the planar area of ​​the external optical component may be smaller than the planar area of ​​the two internal optical components.

[0060] In the illustrated embodiment, the internal optical components 6221 and 6222 are arranged near the third identification feature I3. This arrangement reduces the planar area of ​​the external optical component 6121 (which overlaps with the internal optical components 6221 and 6222), thereby enhancing the structural strength of the outer base 612. In some embodiments, the internal optical components 6221 and 6222 are arranged away from the third identification feature I3. In these embodiments, the outer base 612 may have one or more additional external optical components (not shown) corresponding to the positions of the third identification feature I3 and the internal optical components 6221 and 6222, respectively.

[0061] In some embodiments, the entire bottom surface of the outer base can be designed as a second observation area. For example, an external optical component may occupy the entire bottom of the outer base.

[0062] In the top view shown, the external optical component 6121 has a generally rectangular planar profile. The length direction D along the rectangular profile of the external optical component 6121... L The third identification feature I3 is arranged between the two internal optical components 6221 and 6222. In some embodiments, the planar contours of the internal optical components 6221 and 6222 and the external optical component 6121 may include one or more arc-shaped portions.

[0063] The placement, materials, and planar profile of optical components (e.g., optical component 6121) can take into account various factors, such as weight distribution, structural integrity, and the overall weight limits of the device components. As shown in this embodiment, the external optical component 6121 is arranged toward the geometric center of the outer base 622. For example, in the x and y directions, the distance between the geometric center of the external optical component 6121 and the center of the outer base 622 is typically less than half the distance between the center of the outer base 622 and the outer edge of the outer base 622. Such a layout helps to maintain better overall balance while preserving the structural integrity of the outer base 622. Moreover, such a layout helps to reserve the peripheral area of ​​the base component (e.g., the outer base 622) for other functional components such as sealing and latching mechanisms.

[0064] In the illustrated embodiment, the distance D from the geometric center 6121c of the outer optical component 6121 to the axis of symmetry A1 of the outer base 612 is less than 30% of the length L of the rectangular profile of the outer base 612. In some embodiments, the distance D may be shorter than 30% of the width W of the rectangular profile of the outer base 612. In some embodiments, the distance D may be approximately 76 mm; the length L may be approximately 270 mm; and the width W may be approximately 260 mm.

[0065] In some embodiments, the distance from the geometric center 6121c to the axis of symmetry A2 of the outer base 612 is less than 30% of the length L and / or width W of the rectangular outline of the outer base 612.

[0066] Furthermore, the layout of the optical components (e.g., optical component 6121) can help preserve the central area of ​​the base member (e.g., outer base 622) for use with other functional components, such as support mechanisms. As shown in this embodiment, the outer optical component 6121 is projectively offset from the geometric center of the outer base 622.

[0067] In the illustrated embodiment, the distance D from the geometric center 6121c of the outer optical component 6121 to the axis of symmetry A1 of the outer base 612 is greater than 10% of the length L and / or width W of the rectangular profile of the outer base 612. In some embodiments, the distance from the geometric center 6121c to the axis of symmetry A2 is greater than 10% of the length L and / or width W. In some embodiments, the geometric center 6121c may be located in the central region of the outer base 612.

[0068] In the illustrated embodiment, the inner base 622 further includes additional internal optical components (e.g., optical ports 62a) disposed outside the first observation area Z31. Similarly, the outer base may be further provided with additional external optical components disposed corresponding to the additional optical ports 62a of the inner housing. The additional external optical components may be observably aligned with the additional internal optical components 62a accordingly. In some embodiments, the number of external optical components (e.g., optical ports 6121) is less than the number of internal optical components (e.g., ports 6121, 6122, 62a).

[0069] Therefore, one aspect of this disclosure provides a photomask holding system, including an inner box and an outer box. The inner box is configured to receive a photomask having a first identification feature. The inner box includes: an inner base having a photomask receiving area substantially at its geometric center, the photomask receiving area being surrounded by a peripheral region; and an inner cover configured to engage with the peripheral region of the inner base, thereby defining an interior for receiving the photomask. The inner base has a first observation area defined in the photomask receiving area, the first observation area being correspondingly arranged to allow observation of the first identification feature. The outer box is configured to receive the inner base, the outer box including: an outer base defining a second observation area thereon, wherein, when the outer base receives the inner box, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box.

[0070] In some embodiments, the inner box is also configured to receive a photomask with a pellicle arranged near the first identification feature; the first observation area of ​​the inner base is correspondingly arranged to allow observation of the first identification feature and a portion of the pellicle.

[0071] In some embodiments, the inner base includes two internal optical components hermetically embedded in the first observation area to observe the first identification feature and a portion of the protective film, respectively; wherein, the outer base includes an external optical component embedded in the second observation area and observably aligned with the two internal optical components.

[0072] In some embodiments, one of the two internal optical components has a larger planar area than the other of the two internal optical components.

[0073] In some embodiments, the inner box is further configured to receive a photomask with a protective film, and a protective film frame is disposed between the photomask and the protective film, the protective film being adjacent to the first identification feature; the internal optical components having a large planar area are configured to allow observation of a portion of the protective film frame.

[0074] In some embodiments, the second identification feature is disposed on the protective film frame; the internal optical components having a large planar area are configured to allow observation of the second identification feature.

[0075] In some embodiments, the inner base includes a third identification feature; the external optical components are configured to allow observation of the third identification feature.

[0076] In some embodiments, the external optical component has a rectangular planar profile; the third identification feature is arranged between the two internal optical components along the length of the rectangular profile of the external optical component.

[0077] In some embodiments, the external optical components projectively overlap the two internal optical components.

[0078] In some embodiments, the planar area of ​​the external optical component is larger than the planar area of ​​the two internal optical components.

[0079] In some embodiments, the inner base further includes additional internal optical components arranged outside the first observation area; the outer base further includes additional external optical components arranged outside the second observation area; the number of external optical components is less than the number of internal optical components.

[0080] In some embodiments, the thickness of the photomask accommodating region of the inner base is less than the thickness of the peripheral region, and the photomask accommodating region includes a step profile in its cross-section.

[0081] In some embodiments, the inner base includes electromagnetic interference (EMI) shielding features.

[0082] In some embodiments, the outer base has a substantially rectangular planar profile; the outer optical component has a substantially rectangular planar profile; and a distance from the geometric center of the outer optical component to the axis of symmetry of the outer base is less than 30% of the length of the rectangular profile of the outer base.

[0083] In some embodiments, the internal optical component has a lower reflectance value than the external optical component in the wavelength range of 600 nm to 950 nm.

[0084] In some embodiments, the reflectivity of the external optical component is less than 15%; the reflectivity of the internal optical component is less than 0.5%.

[0085] In some embodiments, the transmittance value of the external optical component is greater than 80%.

[0086] Therefore, one aspect of this disclosure provides a photomask holding system, including an inner box and an outer box. The inner box is configured to receive a photomask adjacent to a pellicle and having a first identification feature. The inner box includes: an inner base having a photomask receiving area substantially at its geometric center and surrounded by a peripheral region; and an inner cover configured to sealably engage with the peripheral region of the inner base, thereby defining an interior for receiving the photomask. The inner base includes two internal optical components hermetically embedded in the photomask receiving area to allow observation of the first identification feature and a portion of the pellicle, respectively. The outer box is configured to receive the inner box and includes: an outer base including external optical components, wherein when the outer base receives the inner box, the external optical components are observably aligned with the two internal optical components, and a second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box.

[0087] In some embodiments, the inner box is further configured to receive a photomask with a protective film adjacent to the first identification feature, and a protective film frame is disposed between the photomask and the protective film; the one of the two internal optical components having the larger planar area is configured to allow observation of a portion of the protective film frame.

[0088] In some embodiments, the second identification feature is disposed on the protective film frame; the internal optical components having a large planar area are configured to allow observation of the second identification feature.

[0089] In some embodiments, the inner base includes a third identification feature; the outer optical assembly is configured to allow observation of the third identification feature; the outer optical assembly has a rectangular planar profile; and the third identification feature is arranged between the two inner optical assemblies along the length of the rectangular profile of the outer optical assembly.

[0090] The embodiments shown and described above are merely examples. Many details, such as other features of the radiation measurement panel and device, are frequently found in the art. Therefore, not many such details have been shown or described. Even though many features and advantages of the present technology, as well as details of structure and function, have been set forth in the foregoing description, this disclosure is merely illustrative and changes may be made in details, particularly in terms of shape, size, and the arrangement of the various parts within the scope of the principles, up to and including the full scope defined by the broad meaning of the terms used in the claims. Therefore, it will be understood that the above embodiments can be modified within the scope of the claims.

Claims

1. A photomask holding system, characterized in that, include: An inner box configured to receive a photomask having a first identifying feature, the inner box comprising: an inner base having a photomask receiving area surrounded by a peripheral region, wherein the inner base has a first observation area defined within the photomask receiving area; and an inner cover configured to engage with the peripheral region of the inner base to define an interior for receiving the photomask; and An outer box configured to receive the inner box, the outer box comprising: an outer base having a second observation area, wherein, when the outer base receives the inner base, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box. The first observation area is configured with two internal optical components to allow the first identification feature to be observed from one of the two internal optical components. The second observation area is configured with an external optical component, and the geometric center of the external optical component is projected off from the geometric center of the outer base and off from the geometric center of the internal optical component. The projection of the internal optical component overlaps the external optical component, and the planar profile of the external optical component includes one or more arc-shaped portions.

2. The photomask holding system as described in claim 1, characterized in that, The photomask has a protective film. The first observation area is configured with two internal optical components to allow observation of the first identification feature and a portion of the protective film, respectively. The second observation area is configured with the external optical components, and the geometric center of the external optical components is projected off from the geometric center of the outer base and off from the geometric center of the two internal optical components. The two internal optical components are projected to overlap the external optical components.

3. A photomask holding system, characterized in that, include: An inner box configured to receive a photomask having a first identifying feature, the inner box comprising: an inner base having a photomask receiving area surrounded by a peripheral region, wherein the inner base has a first observation area defined within the photomask receiving area; and an inner cover configured to engage with the peripheral region of the inner base to define an interior for receiving the photomask; and An outer box configured to receive the inner box, the outer box comprising: an outer base having a second observation area, wherein, when the outer base receives the inner base, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box. The first observation area is configured with two internal optical components to allow the first identification feature to be observed from one of the two internal optical components. The second observation area is configured with an external optical component, and the geometric center of the external optical component is projected off from the geometric center of the outer base and off from the geometric center of the internal optical component. The internal optical component partially overlaps with the external optical component.

4. The photomask holding system as described in claim 3, characterized in that, The photomask has a protective film. The first observation area is configured with two internal optical components to allow observation of the first identification feature and a portion of the protective film, respectively. The second observation area is configured with the external optical components, and the geometric center of the external optical components is projected off from the geometric center of the outer base and off from the geometric center of the two internal optical components. The two internal optical components partially overlap the external optical components.

5. A photomask holding system, characterized in that, include: An inner box configured to receive a photomask having a first identifying feature, the inner box comprising: an inner base having a photomask receiving area surrounded by a peripheral region, wherein the inner base has a first observation area defined within the photomask receiving area; and an inner cover configured to engage with the peripheral region of the inner base to define an interior for receiving the photomask; and An outer box configured to receive the inner box, the outer box comprising: an outer base having a second observation area, wherein, when the outer base receives the inner base, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box. The first observation area is configured with two internal optical components to allow the first identification feature to be observed from one of the two internal optical components. The second observation area is configured with an external optical component, and the projections of the external optical component and the internal optical component are offset from the geometric center of the outer base, while the projections of the internal optical component overlap the external optical component.

6. The photomask holding system as described in claim 5, characterized in that, The photomask has a protective film. The first observation area is configured with two internal optical components to allow observation of the first identification feature and a portion of the protective film, respectively. The second observation area is configured with the external optical components, and the geometric center of the external optical components is projected off from the geometric center of the outer base and off from the geometric center of the two internal optical components. The two internal optical components are projected to overlap the external optical components.

7. A photomask holding system, characterized in that, include: An inner box configured to receive a photomask having a first identifying feature, the inner box comprising: an inner base having a photomask receiving area surrounded by a peripheral region, wherein the inner base has a first observation area defined within the photomask receiving area; and an inner cover configured to engage with the peripheral region of the inner base to define an interior for receiving the photomask; and An outer box configured to receive the inner box, the outer box comprising: an outer base having a second observation area, wherein, when the outer base receives the inner base, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box. The first observation area is configured with two internal optical components to allow the first identification feature to be observed from one of the two internal optical components. The second observation area is configured with an external optical component, and the projection of the internal optical components overlaps with the external optical component. The outer base has a rectangular outline and an axis of symmetry. The distance from the geometric center of the external optical component to the axis of symmetry is less than 30% of the length of the rectangular outline, or the distance from the geometric center of the external optical component to the axis of symmetry is less than 30% of the width of the rectangular outline.

8. The photomask holding system as described in claim 7, characterized in that, The photomask has a protective film, and the first observation area is configured with two internal optical components to allow observation of the first identification feature and a portion of the protective film, respectively, and both internal optical components project onto the overlapping external optical components.

9. A photomask holding system, characterized in that, include: An inner box configured to receive a photomask having a first identifying feature, the inner box comprising: an inner base having a photomask receiving area surrounded by a peripheral region, wherein the inner base has a first observation area defined within the photomask receiving area; and an inner cover configured to engage with the peripheral region of the inner base to define an interior for receiving the photomask; and An outer box configured to receive the inner box, the outer box comprising: an outer base having a second observation area, wherein, when the outer base receives the inner base, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box. The first observation area is configured with two internal optical components to allow the first identification feature to be observed from one of the two internal optical components. The second observation area is configured with an external optical component, and the projection of the internal optical components overlaps with the external optical component. The outer base has a rectangular outline and an axis of symmetry. The distance from the geometric center of the external optical component to the axis of symmetry is greater than 10% of the length of the rectangular outline, or the distance from the geometric center of the external optical component to the axis of symmetry is greater than 10% of the width of the rectangular outline.

10. The photomask holding system as described in claim 9, characterized in that, The photomask has a protective film, and the first observation area is configured with two internal optical components to allow observation of the first identification feature and a portion of the protective film, respectively, and both internal optical components project onto the overlapping external optical components.

11. A photomask holding system, characterized in that, include: An inner box configured to receive a photomask having a first identifying feature, the inner box comprising: an inner base having a photomask receiving area surrounded by a peripheral region, wherein the inner base has a first observation area defined within the photomask receiving area; and an inner cover configured to engage with the peripheral region of the inner base to define an interior for receiving the photomask; and An outer box configured to receive the inner box, the outer box comprising: an outer base having a second observation area, wherein, when the outer base receives the inner base, the second observation area is observably aligned with the first observation area of ​​the inner box; and an outer cover configured to engage with the outer base and cover the inner box. The first observation area is configured with two internal optical components and the second observation area is configured with one external optical component. The first identification feature of the photomask can be confirmed by optical scanning of the external optical component and one of the two internal optical components.

12. The photomask holding system as described in claim 11, characterized in that, The photomask has a protective film. The first observation area is equipped with two internal optical components and the second observation area is equipped with an external optical component. The first identification feature of the photomask and a part of the protective film can be confirmed by optical scanning of the external optical component and the two internal optical components.

13. The photomask holding system as described in claim 11 or 12, characterized in that, The optical scan is performed in a wavelength range between 600 nm and 950 nm, and the internal optical component has a lower reflectivity value than the external optical component.

14. The photomask holding system as described in claim 11 or 12, characterized in that, The optical scan is performed in a wavelength range between 600 nm and 950 nm, and the reflectivity of the external optical component relative to the aforementioned wavelength range is less than 15%.

15. The photomask holding system as described in claim 11 or 12, characterized in that, The transmittance of the external optical component is greater than 80%.

16. The photomask holding system as described in claim 1, 3, 5, 7, or 9, characterized in that, The second observation area is aligned with the first observation area, and the first identification feature of the photomask can be confirmed by optical scanning of one of the external optical components and one of the internal optical components.

17. The photomask holding system as described in claim 1, 3, 5, 7, 9, or 11, characterized in that, A third identification feature is provided on the bottom side of the inner base, and the third identification feature of the inner base can be confirmed by optical scanning of the external optical components.

18. The photomask holding system as described in claim 2, 4, 6, 8, or 10, characterized in that, The second observation area is aligned with the first observation area, and the first identification feature of the photomask and a portion of the protective film can be confirmed by optical scanning of the external optical components and the two internal optical components, respectively.

19. The photomask holding system as described in claim 2, 4, 6, 8, 10, or 12, characterized in that, The photomask has a second identification feature, and the second identification feature can be observed by one of the internal optical components of the protective film. The second observation area is aligned with the first observation area. The first identification feature and the second identification feature of the photomask can be confirmed by optical scanning of the external optical component and the two internal optical components, respectively.

20. The photomask holding system as described in claim 2, 4, 6, 8, 10, or 12, characterized in that, The photomask has a second identification feature, and the larger of the two internal optical components can observe a portion of the protective film and the second identification feature. The second observation area is aligned with the first observation area. The portion of the protective film of the photomask and the second identification feature can be confirmed by optical scanning of the larger of the two internal optical components and the external optical components.

21. A method for providing an observation mask with a mask holding system, the mask holding system comprising an inner box for housing the mask and an outer box for housing the inner box, wherein, The inner box includes an inner base for receiving the photomask, and the outer box includes an outer base for receiving the inner base, characterized in that the method includes: Two internal optical components are configured on the inner base, and the projection of the internal optical components is offset from the geometric center of the inner base, so as to allow a first identification feature of the photomask to be observed through one of the two internal optical components; and An external optical component is configured on the outer base, and the geometric center of the external optical component is projected off from the geometric center of the outer base and the geometric center of the inner base, and the projection of the inner optical component overlaps with the external optical component, so as to allow the first identification feature of the photomask to be confirmed by optical scanning of the external optical component and one of the two inner optical components.

22. The method for observing the photomask as described in claim 21, characterized in that, include: The internal optical component is partially overlapped with the external optical component, and the partial overlap means that the first identification feature can be observed from the external optical component through the internal optical component.

23. The method for observing the photomask as described in claim 21, characterized in that, include: When a third identification feature is provided on the bottom side of the inner base, the third identification feature of the inner base can be confirmed by optical scanning of the external optical components.

24. The method for observing the photomask as described in claim 21, characterized in that, This includes: when the outer base has a rectangular outline and an axis of symmetry, the distance from the geometric center of the external optical component to the axis of symmetry is less than 30% of the length of the rectangular outline, or the distance from the geometric center of the external optical component to the axis of symmetry is less than 30% of the width of the rectangular outline.

25. The method for observing the photomask as described in claim 21, characterized in that, This includes situations where the outer base has a rectangular profile and an axis of symmetry, and the distance from the geometric center of the outer optical component to the axis of symmetry is greater than 10% of the length of the rectangular profile, or the distance from the geometric center of the outer optical component to the axis of symmetry is greater than 10% of the width of the rectangular profile.

26. The method for observing the photomask as described in claim 21, characterized in that, include: When the photomask has a protective film and a second identification feature disposed on a protective film frame, another internal optical component is projected off-center from the geometric center of the inner base to allow observation of the second identification feature; and, the external optical component is configured on the outer base, and the geometric center of the external optical component is offset off-center from the geometric center of the outer base and the two internal optical components, and the two internal optical components are projected to overlap the external optical component, so as to allow confirmation of a portion of the protective film of the photomask and the second identification feature by optical scanning of the external optical component and the other internal optical component.

27. The method for observing the photomask as described in claim 21, characterized in that, include: When the photomask has a protective film and a second identification feature disposed on a protective film frame, the two internal optical components are offset from the geometric center of the inner base to allow observation of the first identification feature and the second identification feature respectively; and the external optical components are configured on the outer base, and the geometric center of the external optical components is projected off from the geometric center of the outer base and the geometric center of the two internal optical components, and the projections of the two internal optical components overlap the external optical components, so as to allow the first identification feature and the second identification feature of the photomask to be confirmed respectively by optical scanning of the external optical components and the two internal optical components.

28. The method for observing the photomask as described in claim 21, characterized in that, include: When the photomask has a protective film, the two internal optical components are projected off-center from the geometric center of the inner base to allow observation of the first identification feature and a portion of the protective film, respectively; and the external optical components are configured on the outer base, with the geometric center of the external optical components projected off-center from the geometric center of the outer base and off-center from the geometric centers of the two internal optical components, and the two internal optical components projecting overlap with the external optical components, to allow confirmation of the first identification feature of the photomask and a portion of the protective film by optical scanning of the external optical components and the two internal optical components.

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