Reticle pod with coated sensor zone

Abstract

To provide a reticle pod that can form a reflective material for interfacing with a sensor on a process tool without requiring wet coating of the entire reticle pod.SOLUTION: In a reticle pod, the sensor zones 102 of a base plate 100 are formed on the inner pod of a reticle container using a dry coating method. The use of separate zones and a dry coating method to apply these separate zones overcomes the problems of inconsistency and difficulty in cleaning the inner pod of the reticle container or maintaining the reflectivity of the inner pod of the reticle container compared to an inner pod that is fully plated with a material or other wet coating applied material.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 011,581, filed April 17, 2020, the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0002] The present disclosure is directed to forming sensor zones on reticle pods, particularly reticle pods such as extreme ultraviolet (EUV) reticle pods. [Background technology]

[0003] Reticle pods are used to house photolithography masks used during semiconductor processing, such as during extreme ultraviolet (EUV) processing. Reticle pods may include a metal inner pod that is handled and manipulated by one or more tools during processing. Some of the tools may use reflectance to determine the distance of the inner pod from one or more sensors in the tool. Reticle pods are typically cleaned using deionized (DI) water, which can cause oxidation of some materials.

[0004] The inner pod of the reticle pod can be wet coated with chrome to improve reflectivity and appearance and to resist loss of reflectivity due to oxidation caused by DI water cleaning. However, the shape of the reticle pod makes it difficult to wet coat. Summary of the Invention

[0005] The present disclosure is directed to forming sensor zones on reticle pods, particularly reticle pods such as extreme ultraviolet (EUV) reticle pods.

[0006] By selectively applying a reflective coating to individual sensor zones on a reticle pod using a dry coating process, a reflective material can be provided for interfacing with sensors on a process tool without requiring wet coating of the entire reticle pod. Additionally, the reflective coating can be provided to have a desired thickness and strength.

[0007] In one embodiment, the pod includes a base plate having a base plate surface. The base plate surface includes a base plate surface material and a reflective material. The reflective material of the base plate surface is disposed in one or more distinct base plate sensor zones. The pod also includes a cover having a cover surface. The cover surface includes a cover surface material and a reflective material. The reflective material of the cover surface is disposed in one or more distinct cover sensor zones.

[0008] In one embodiment, the pod is an EUV reticle pod. In one embodiment, the pod further includes an outer pod dome and an outer pod door, the pod dome and the pod door configured to encase the base plate and the cover within the pod dome when the door is attached to the pod dome.

[0009] In one embodiment, the reflective material has a spectral reflectance of about 50% to about 70% at a wavelength of 880 nm. In one embodiment, the reflective material includes chromium. In one embodiment, only the reflective material includes chromium.

[0010] In one embodiment, the one or more base plate sensor zones and the one or more cover sensor zones are positioned such that the distance between the pod and the detector can be determined from reading the one or more base plate sensor zones and the one or more cover sensor zones.

[0011] In one embodiment, the base plate surface comprises one of aluminum or nickel, and the cover surface is one of aluminum or nickel.

[0012] In one embodiment, a method of manufacturing a reticle pod includes applying a reflective material to each of one or more individual base plate sensor zones of a base plate of the reticle pod using a dry coating process, and applying a reflective material to each of one or more individual cover sensor zones of a cover of the reticle pod using a dry coating process.

[0013] In one embodiment, the reflective material has a spectral reflectance of about 50% to about 70% at a wavelength of 880 nm.

[0014] In one embodiment, the dry coating process is selected from the group consisting of physical vapor deposition, sputter deposition, chemical vapor deposition, and plasma enhanced chemical vapor deposition.

[0015] In one embodiment, the one or more base plate sensor zones and the one or more cover sensor zones are positioned such that the distance between the pod and the detector can be determined from reading the one or more base plate sensor zones and the one or more cover sensor zones.

[0016] The present disclosure may be more fully understood from consideration of the following description of various exemplary embodiments in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0017] [Figure 1A] FIG. 2 is a bottom view of a base plate of a reticle pod according to one embodiment. [Figure 1B] FIG. 2 is a bottom view of a cover for a reticle pod according to one embodiment. [Figure 1C] FIG. 1C is a side view of the cover of the reticle pod shown in FIG. [Diagram 2] 1 is a flow chart of a method for manufacturing a reticle pod according to one embodiment. [Diagram 3] FIG. 2 illustrates a reticle pod including an outer pod and an inner pod according to one embodiment. [Figure 4] 1 is a schematic diagram of a reticle pod in an extreme ultraviolet (EUV) tool according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] While the present disclosure is amenable to various modifications and alternative forms, details of which have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the specific exemplary embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

[0019] The present disclosure is directed to forming sensor zones on reticle pods, particularly reticle pods such as extreme ultraviolet (EUV) reticle pods.

[0020] 1A shows a plan view of the bottom of a base plate of a reticle pod according to one embodiment. The base plate 100 forms a portion of the inner pod of the reticle pod. The base plate 100 includes one or more sensor zones 102.

[0021] The base plate 100 includes a base plate surface material that forms a surface of the base plate 100. The base plate surface material can be a material used to form a base plate, such as aluminum, or any other suitable material for the base plate 100 of a reticle pod. The base plate 100 can further include features specifically for manipulating the reticle pod or base plate 100. The base plate surface material can be a coating that is applied to the base plate 100 to form a surface of the base plate 100, such as a nickel coating.

[0022] In one or more embodiments, at least one sensor zone 102 may be provided on the surface of the base plate 100. The sensor zone 102 is a distinct zone made of a reflective material. The sensor zone 102 is a defined area of ​​reflective material formed on a segment of the surface of the base plate 100. The one or more sensor zones 102 cover an area less than the entire surface of the base plate 100. The sensor zone 102 may have any suitable shape for presenting a reflective material to be read by one or more sensors, such as a sensor included in a tool that handles a reticle pod that includes the base plate 100. The sensor zone 102 may include a sensor zone material, which may be a different material than the surrounding base plate material on the surface of the base plate 100. For example, the base plate 100 may be made of aluminum, and the sensor zone material is applied to exposed aluminum material or a nickel coating on the base plate 100 to form the distinct sensor zone 102. In one embodiment, the sensor zone material may be placed in contact with a coating applied to the surface material of the base plate 100 to form the distinct sensor zone 102. In one embodiment, the sensor zones 102 may be applied with a coating made of a different material than the sensor zone material used in the sensor zones 102. In one embodiment, the sensor zones 102 may be applied with a coating that includes at least some of the same materials as the sensor zones 102, but is provided by a different method than a dry coating. For example, a chrome coating may be applied to a chrome surface material for the base plate 100, and the sensor zones 102 are formed by applying additional chrome by a dry coating method, providing chrome at a different density, thickness, and uniformity within those sensor zones 102, as compared to a base plate surface material that is wet coated chrome on nickel.

[0023] The sensor zone 102 may be provided on any portion of the base plate 100 where a sensor may attempt to detect the base plate 100. In one embodiment, the sensor zone 102 is provided on the bottom surface of the base plate 100 and is visible from the bottom of the reticle pod when the base plate 100 is assembled with a cover, such as the cover 150 shown in FIG. 1B and described below. In one embodiment, one sensor zone 102 is included on the base plate 100. In one embodiment, multiple sensor zones 102 are included on the base plate. In one embodiment, the sensor zone 102 is located on the bottom surface of the base plate 100 such that it is not obscured by a cover, such as the cover 150 shown in FIGS. 1B and 1C, when a reticle pod including the base plate 100 is assembled. In the embodiment shown in FIG. 1A, four sensor zones 102 are provided on the base plate 100 and four sensor zones 102 are provided on the bottom surface of the base plate 100.

[0024] The reflective material used in the sensor zones 102 has a known spectral reflectance selected for use in a detection system of a tool that uses a pod that includes the base plate 100. In some embodiments, the reflective material can have a reflectance that is different from the reflectance of the base plate surface material, such as greater than or less than the reflectance of the base plate surface material. The sensor zones 102 can provide a spectral reflectance at one or more predetermined wavelengths that are within a known, predetermined range such that light reflected by the sensor zones 102 is associated with a particular distance of the inner pod base plate 100 from a fiducial with a tool that uses a reticle, such as an extreme ultraviolet (EUV) tool for processing wafers. As a non-limiting example, the range for the spectral reflectance of each of the sensor zones 102 is between about 57% and about 63% for at least one of the one or more predetermined wavelengths. In one embodiment, each of the sensor zones 102 has a spectral reflectance of between about 57% and about 63% at a wavelength of 880 nm. The sensor zones can include any suitable reflective material that has the desired spectral reflectance properties and can be applied by a dry coating method. The reflective material may be an inert material selected to be non-reactive during processing by the tool. The reflective material may include, by way of non-limiting example, chrome. In one embodiment, only the sensor zone or zones 102 and 152 included in the reticle pod include chrome.

[0025] The reflective material can be provided to the sensor zones 102 by dry coating methods such as physical vapor deposition (PVD), sputter deposition, chemical vapor deposition (CVD), and plasma enhanced chemical vapor deposition (PE-CVD). The resulting sensor zones 102 can have a more durable and uniform coating within those sensor zones 102 as compared to wet coating methods such as plating the entire base plate 100. Improved durability can in turn improve the appearance and maintenance of proper reflectivity for the sensor zones 102.

[0026] Figure IB shows a plan view of the bottom of a reticle pod cover 150 according to one embodiment, and Figure 1C shows a side view of the reticle pod cover 150 shown in Figure IB. The cover 150 includes a sensor zone 152.

[0027] The cover 150 is configured to be bonded to a base plate, such as the base plate 100 shown in FIG. 1A, to form a reticle pod configured to house a reticle. The cover 150 can be configured such that a reticle housing portion 158 is surrounded by the base plate 100. The cover 150 can further include features for manipulating the reticle pod or the cover 150, among other things. The cover 150 can be made of any suitable material, such as aluminum. The surface of the cover 150 is a cover surface material, which can be the material forming the body of the cover 150 or a coating formed thereon, such as nickel.

[0028] In addition to or instead of the sensor zone 152 provided on the base plate 100, one or more sensor zones 102 can be provided on the cover 150. The one or more sensor zones 152 are individual zones that include a reflective material. The one or more sensor zones 152 cover an area that is less than the entire surface of the cover 150. The reflective material can be applied by a dry coating process. The sensor zones 152 can have any suitable shape to present a reflective material that is read by one or more sensors, such as sensors included in a tool that handles a reticle pod that includes the cover 150. The sensor zones 152 can use the same or different reflective material from a sensor zone on a base plate that is used with the cover 150, such as the reflective material of the sensor zone 102 on the base plate 100 shown in FIG. 1A. The one or more sensor zones can be provided on the cover 150 such that the one or more sensor zones can be read by a tool when the cover 150 is combined with a base plate, such as the base plate 100, to form an inner pod of a reticle pod. In one embodiment, the sensor zones 152 are positioned such that they are not obscured by a base plate, such as base plate 100 shown in Figure 1A, when a reticle pod including the base plate and cover 150 is assembled. In the embodiment shown in Figures 1B and 1C, four sensor zones 152 are provided, two of the sensor zones 152 on the bottom surface of extension 154 from side 156 of the cover as seen in Figure 1B, and two more sensor zones on the outward facing side of cover 150 as seen in Figure 1C.

[0029] The reflective material used in the sensor zones 152 has a known spectral reflectance selected for use with a detection system of a tool that uses a pod that includes the cover 150. The reflective material can be an inert material selected to be non-reactive during processing by the tool. The sensor zones 152 can provide a spectral reflectance at one or more predetermined wavelengths that are within a known, predetermined range such that light reflected by the sensor zones 152 is associated with a particular distance of the inner pod cover 150 from a reference with a tool, such as an extreme ultraviolet (EUV) tool for processing wafers using a reticle. As a non-limiting example, the range for the spectral reflectance of each of the sensor zones 152 is between about 57% and about 63% for at least one of the one or more predetermined wavelengths. In one embodiment, each of the sensor zones 152 has a spectral reflectance between about 57% and about 63% at a wavelength of 880 nm. The sensor zones 152 can include any suitable reflective material that has the desired spectral reflectance properties and can be applied by a dry coating method. The reflective material can be an inert material selected to be non-reactive during processing by the tool. The reflective material may include, by way of non-limiting example, chrome, hi one embodiment, only the sensor zone or zones 102 and 152 included in the reticle pod include chrome.

[0030] The reflective material can be provided to the sensor zones 152 by dry coating methods such as physical vapor deposition (PVD), sputter deposition, chemical vapor deposition (CVD), and plasma enhanced chemical vapor deposition (PE-CVD). The resulting sensor zones 152 can have a more durable and uniform coating within those sensor zones 152 as compared to wet coating methods such as plating the entire cover 150. Improved durability can in turn improve the appearance and maintenance of proper reflectivity for the sensor zones 152.

[0031] Cover 150 can include additional features for the function of the reticle pod it is contained in. For example, cover 150 can include a reticle receiving portion 154 ominous portion of an interior space configured to receive a reticle, such as a photolithography mask.

[0032] 2 shows a flow chart of a method for manufacturing a reticle pod according to one embodiment. The method 200 includes providing a base plate 202, optionally coating the base plate 204, applying a reflective material to one or more sensor zones on the base plate using a dry coating method 206, providing a cover 208, optionally coating the cover 210, and applying a reflective material to one or more sensor zones on the cover using a dry coating method 212. Some embodiments of the method may also include a polishing step in which the one or more sensor zones are polished to achieve a desired spectral reflectance.

[0033] At 202, a base plate can be provided. The base plate is a formed base plate for use in a reticle pod. The base plate can be any material suitable for a reticle pod base plate, such as, by way of non-limiting example, aluminum. The base plate provided at 202 can include all of the features of a completed base plate at the time the base plate is provided at 202, such as walls defining a reticle receiving portion, a reticle support, features for engaging a cover, features for engaging automation in a tool that uses or manipulates the reticle, etc.

[0034] At 204, the base plate may optionally be coated. The coating may be any suitable coating applied to the base plate, such as a coating that improves appearance, provides wear resistance, provides an inert surface compatible with use in a processing tool, or any other desired function of such a coating. The coating applied at 204 may be by a wet coating process, such as plating, or any other coating method that involves immersing the base plate in a liquid. At 204, one or more such coatings may be applied to the base plate. One of the coatings applied to the base plate at 204 may be nickel.

[0035] In some embodiments, a reflective material can be applied to one or more discrete locations on the base plate to form the sensor zones at 206 using a dry coating method. The dry coating method can be any method that does not involve applying a liquid to the base plate during coating. The dry coating method can be, by way of non-limiting examples, physical vapor deposition (PVD), sputter deposition, chemical vapor deposition (CVD), and plasma-enhanced chemical vapor deposition (PE-CVD). The sensor zone or zones to which the reflective material is applied at 206 are discrete zones, and these discrete zones constitute less than the entire surface of the base plate. The sensor zone or zones can be defined, for example, through a mask applied during deposition by the dry coating method, the mask allowing deposition only on the sensor zone or zones.

[0036] The reflective material applied to the base plate at 206 has a known spectral reflectance selected for use with a detection system of a tool that uses the pod that includes the base plate. The reflective material can be an inert material selected to be non-reactive during use of the reticle pod in the tool. The reflective material can include, by way of non-limiting example, chrome. The reflective material can be applied to the sensor zones such that the sensor zones provide a spectral reflectance at one or more predetermined wavelengths that are within a known, predetermined range such that light reflected by the sensor zones is associated with a particular distance of the inner pod base plate from a fiducial using a tool, such as an extreme ultraviolet (EUV) tool for performing processing using the reticle. By way of non-limiting example, the range for the spectral reflectance of each of the sensor zones is between about 50% and about 70% for at least one of the one or more predetermined wavelengths. In one embodiment, each of the sensor zones has a spectral reflectance of between about 50% and about 70% at a wavelength of 880 nm.

[0037] At 208, a cover is provided. The cover is a cover formed for a reticle pod. The cover can be any material suitable for a reticle pod cover, such as, by way of non-limiting example, aluminum. The cover provided at 208 can include all the features of a finished cover at the time the cover is provided at 208, such as walls defining a reticle receiving portion, features for engaging with a base plate, features for engaging with automation in a tool that uses the reticle, etc.

[0038] Optionally, at 210, the cover is coated. The coating can be any suitable coating applied to the cover, such as a coating that improves appearance, provides wear resistance, provides an inert surface compatible for use in processing with a reticle, or any other desired function of such a coating. The coating applied at 210 can be a wet coating process, such as plating, or any other coating method that includes immersing the cover in a liquid. At 210, one or more such coatings can be applied to the cover. The one or more coatings applied to the cover at 210 can be the same coating as the coating applied to the base plate at 204. The one or more coatings applied to the cover at 210 can include one or more coatings that are different from the one or more coatings applied to the base plate at 204. One of the coatings applied at 210 can be nickel.

[0039] In some embodiments, a reflective material can be applied to one or more discrete locations on the cover to form the sensor zones at 212 using a dry coating method. The dry coating method can be any method that does not involve applying a liquid to the cover during coating. The dry coating method can be, by way of non-limiting examples, physical vapor deposition (PVD), sputter deposition, chemical vapor deposition (CVD), and plasma-enhanced chemical vapor deposition (PE-CVD). The sensor zone or zones to which the reflective material is applied at 212 are discrete zones, and these discrete zones constitute less than the entire surface of the cover. The sensor zone or zones can be defined, for example, through a mask applied during deposition by the dry coating method, the mask allowing deposition only on the sensor zone or zones.

[0040] The reflective material applied to the cover at 212 has a known spectral reflectance selected for use with a detection system of a tool that uses the pod that includes the cover. The reflective material can be an inert material selected so as not to react when a reticle is in use. The reflective material can include, as a non-limiting example, chrome. The reflective material can be applied to the sensor zones such that the sensor zones provide a spectral reflectance at one or more predetermined wavelengths that are within a known, predetermined range to allow light reflected by the sensor zone to be associated with a particular distance of the inner pod base plate from a fiducial using a tool, such as an extreme ultraviolet (EUV) tool for performing processing using the reticle. As a non-limiting example, the range for the spectral reflectance of each of the sensor zones is between about 50% and about 70% for at least one of the one or more predetermined wavelengths. In one embodiment, each of the sensor zones has a spectral reflectance of between about 50% and about 70% at a wavelength of 880 nm. In some cases, the sensor zones may be polished to achieve a desired spectral reflectance.

[0041] The base plate and cover processed during method 200 can be used as an inner pod of a reticle pod for housing a reticle, for example, to house a photolithography mask used for extreme ultraviolet (EUV) processing of a wafer.

[0042] 3 illustrates a reticle pod including an outer pod and an inner pod according to one embodiment. Reticle pod 300 includes inner pod 302, which includes a cover 304 and a base plate 306. Reticle pod 300 further includes outer pod 308, which includes an outer pod dome 310 and an outer pod door 312. Reticle pod 300 can be used to enclose a reticle 316. Reticle 316 can be any suitable reticle, such as, by way of non-limiting example, a photolithography mask used in processing wafers using extreme ultraviolet (EUV).

[0043] The inner pod 302 includes a cover 304 and a base plate 306. The cover 304 and the base plate 306 are configured to be joined together. The cover 304 and the base plate 306 together define an interior space sized and shaped to accommodate a reticle, for example a photolithography mask used in extreme ultraviolet (EUV) processing of a wafer. In some embodiments, at least one of the cover 304 and the base plate 306 each include one or more sensor zones 314 that are individual zones that include a reflective material. In some embodiments, both the cover 304 and the base plate 306 each include one or more of the sensor zones 314. The sensor zones 314 can be sensor zones 102 and 152 as described above. In the view shown in FIG. 3, the sensor zones 314 along the sides of the cover 304 are visible, with other zones obscured by other components from the perspective of FIG. 3. Other sensor zones 304 may be provided on the sides or bottom not visible in the perspective view of Figure 3, such as at the locations of sensor zones 102 and 152 shown in Figures 1A and 1B. Reflective material may be applied to the sensor zones of cover 304 and base plate 306 by a dry coating process. Cover 304 may be, for example, cover 150 as described above and shown in Figure 1B. Base plate 306 may be, for example, base plate 100 as described above and shown in Figure 1A.

[0044] The outer pod 308 is configured to house the inner pod 302 within an interior space defined by an outer pod dome 310 and an outer pod door 312. The outer pod dome can be secured to the outer pod door 312 to enclose the interior space and house the inner pod 302, for example, during transport and handling of the reticle pod 300. The outer pod dome 310 and the outer pod door 312 can each include or be made entirely of one or more polymeric materials.

[0045] 4 shows a schematic diagram of a reticle pod in an extreme ultraviolet (EUV) tool according to one embodiment. In the embodiment shown in FIG. 4, an inner pod 400 is placed in a tool 402.

[0046] Inner pod 400 may be any suitable inner pod, such as inner pod 302, or an inner pod that includes base plate 100 and cover 150. Inner pod 400 includes multiple sensor zones 404.

[0047] The tool 402 may be any suitable tool that is handled or operated on the inner pod 400. As a non-limiting example, the tool 402 may be an extreme ultraviolet (EUV) tool that uses a reticle, such as a photolithography mask. The tool 402 may be in a vacuum chamber, and the inner pod 400 is removed from the outer pod (not shown) and placed in the tool 402 in the vacuum chamber. During use of the reticle in the tool 402, a cover may be removed from a base plate of the inner pod 400 to expose the reticle contained within the inner pod 400. The tool 402 includes a light source 406 and a detector 408. The light source 406 and the detector 408 are positioned such that light provided by the light source 406 may be reflected by the sensor zone 404 toward the detector 408, and light detected at the detector 408 may determine a distance to the inner pod 400. The light source may provide light at one or more predetermined wavelengths, including, as a non-limiting example, 880 nm. The sensor zones 404 of the inner pod 400 can provide a spectral reflectance at one or more predetermined wavelengths that are within a known, predetermined range to allow light detected at the detector 408 to be associated with a particular distance of the inner pod 400. As a non-limiting example, the range for the spectral reflectance of each of the sensor zones 404 is between about 50% and about 70% for at least one of the one or more predetermined wavelengths. In one embodiment, each of the sensor zones 404 has a spectral reflectance of between about 50% and about 70% at 880 nm.

[0048] Aspects: It is understood that any of the embodiments 1-9 can be combined with any of the embodiments 10-16.

[0049] Aspect 1. A base plate having a base plate surface, the base plate surface comprising a base plate surface material; a cover having a cover surface, the cover surface including a cover surface material; one or more discrete sensor zones, each of the sensor zones including a reflective material, the one or more discrete sensor zones disposed on one or both of the base plate surface and the cover surface; A pod equipped with

[0050] Aspect 2. The pod of aspect 1, wherein the pod is an EUV reticle pod.

[0051] Aspect 3. The pod of aspect 2, further comprising an outer pod dome and an outer pod door, the pod dome and the pod door configured to encase the base plate and the cover within the pod dome when the door is attached to the pod dome.

[0052] Aspect 4. The pod of any one of Aspects 1 to 3, wherein the reflective material has a spectral reflectance of about 50% to about 70% at a wavelength of 880 nm.

[0053] Aspect 5. The pod of any one of aspects 1-4, wherein the reflective material has a reflectance different from the reflectance of the base plate surface material.

[0054] Aspect 6. The pod of any one of Aspects 1-5, wherein the reflective material includes chromium.

[0055] Aspect 7. The pod of aspect 6, wherein only the reflective material includes the chrome.

[0056] Aspect 8. A pod described in any one of aspects 1 to 7, wherein the one or more sensor zones are positioned such that the distance between the pod and a detector can be determined from reading the one or more sensor zones.

[0057] Aspect 9. A pod described in any one of aspects 1 to 8, wherein the base plate surface comprises one of aluminum or nickel, and the cover surface is one of aluminum or nickel.

[0058] Aspect 10. A pod described in any one of aspects 1 to 9, wherein each of the base plate surface and the cover surface includes one or more of the individual sensor zones.

[0059] Embodiment 11. A method of manufacturing a reticle pod, comprising: applying a reflective material to each of one or more individual sensor zones on one of a base plate of the reticle pod or a cover of the reticle pod using a dry coating process; A method comprising:

[0060] Aspect 12. The method of aspect 11, wherein the reflective material has a spectral reflectance different from the spectral reflectance of the base plate and the spectral reflectance of the cover.

[0061] Aspect 13. The method of any one of Aspects 11-12, wherein the reflective material has a spectral reflectance of about 50% to about 70% at a wavelength of 880 nm.

[0062] Aspect 14. The method of any one of aspects 11 to 13, wherein the one of the base plate or the cover includes a surface material, and the reflective material has a reflectivity different from the reflectivity of the surface material.

[0063] Embodiment 15. The method of any one of embodiments 11-14, further comprising applying a coating to said one of the base plate and the cover.

[0064] Example 16. The method of any one of Examples 11 to 15, wherein the dry coating process is selected from the group consisting of physical vapor deposition, sputter deposition, chemical vapor deposition, and plasma-enhanced chemical vapor deposition.

[0065] Aspect 17. A method according to any one of aspects 11 to 16, wherein the one or more base plate sensor zones and the one or more cover sensor zones are positioned such that the distance between the pod and the detector can be determined from reading the one or more base plate sensor zones and the one or more cover sensor zones.

[0066] Aspect 18. A method according to any one of aspects 11 to 17, further comprising applying the reflective material to each of one or more individual sensor zones on the base plate of the reticle pod or the cover of the reticle pod using the dry coating process.

[0067] The examples disclosed in this application should be considered in all respects as illustrative and not restrictive. The scope of the disclosure is indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalence of the claims are intended to be embraced therein.

Claims

1. a base plate having a base plate surface, the base plate surface including a base plate surface material; a cover having a cover surface, the cover surface including a cover surface material; one or more discrete sensor zones, each of the sensor zones including a reflective material, the one or more discrete sensor zones disposed on one or both of the base plate surface and the cover surface; A pod equipped with

2. The pod of claim 1 , wherein the pod is an EUV reticle pod.

3. 3. The pod of claim 2, further comprising an outer pod dome and an outer pod door, the pod dome and the pod door configured to encase the base plate and the cover within the pod dome when the door is attached to the pod dome.

4. The pod of claim 1 , wherein the reflective material has a spectral reflectance of about 50% to about 70% at a wavelength of 880 nm.

5. The pod of claim 1 , wherein the reflective material has a reflectivity different than a reflectivity of the base plate surface material.

6. The pod of claim 1 , wherein the reflective material comprises chrome.

7. The pod of claim 6 , wherein only the reflective material comprises the chrome.

8. The pod of claim 1 , wherein the one or more baseplate sensor zones are positioned such that a distance between the pod and a detector can be determined from reading the one or more sensor zones.

9. The pod of claim 1 , wherein the base plate surface comprises one of aluminum or nickel and the cover surface is one of aluminum or nickel.

10. The pod of claim 1 , wherein the base plate surface and the cover surface each include one or more of the individual sensor zones.

11. 1. A method of manufacturing a reticle pod, comprising: applying a reflective material to each of one or more individual sensor zones on one of a base plate of the reticle pod or a cover of the reticle pod using a dry coating process; A method comprising:

12. The method of claim 11 , wherein the reflective material has a spectral reflectance that is different from a spectral reflectance of the base plate and a spectral reflectance of the cover.

13. The method of claim 11 , wherein the reflective material has a spectral reflectance of about 50% to about 70% at a wavelength of 880 nm.

14. The method of claim 11 , wherein the one of the base plate or the cover includes a surface material, and the reflective material has a reflectivity different from a reflectivity of the surface material.

15. The method of claim 11 , further comprising applying a coating to said one of said base plate and said cover.

16. The method of claim 11 , wherein the dry coating process is selected from the group consisting of physical vapor deposition, sputter deposition, chemical vapor deposition, and plasma enhanced chemical vapor deposition.

17. The method of claim 11 , wherein the one or more sensor zones are positioned such that a distance between the pod and a detector can be determined from reading the one or more base plate sensor zones and the one or more cover sensor zones.

18. The method of claim 11 , further comprising applying the reflective material to each of one or more individual sensor zones on the base plate of the reticle pod or the cover of the reticle pod using the dry coating process.

19. The method of claim 18 , further comprising polishing the reflective material to achieve a desired reflectivity at the one or more individual sensor zones.

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