FIELD

{0001 j The present disclosure relates to optica! elements designed to operate in harsh, environments, To accomplish this end, the optical -elements are provided with one or more protective layers to shield the optical element from damage that otherwise would he caused by unprotected exposure to a harsh environment. Such an arrangement is advantageously deployed where the harsh environment is in a vacuum chamber of an apparatus for generating extreme ultraviolet ("EUV") radiation from a plasma created, through discharge or laser ablation of a source material. In this application, the optical elements are used, for example, to collect and direct the radiatkm for utilization outside of the vacuum chamber, e.g., for semiconductor photolithography.

BACKGROUND

[0002] Extreme, ultraviolet light, e.g., .electromagnetic radiation having wavelengths of around 50 nm or less (also sometimes referred to as soft x-rays), and including light at a wavelength of about 13.5 nm, can be used in photolithography processes to produce extremely small features in. substrates such as silicon wafers, [0003] Methods for generating EUV light include converting a target material from a liquid state into a plasma state.. The target material preferabl includes at least one element, e.g., xenon, lithium or tin,, with one or more emission lines in the EUV range. In One such method, often termed laser produced plasma ("LPP"). the required plasma can be produced by using a laser beam to irradiate a target material having the required line-emitting element.

000 ] One LPP technique -involves generating a stream of target material droplets and irradiating at least some of the droplets with laser light pulses. In more theoretical -terms, LPP light sources generate EUV radiation by depositing laser energy ^' into a target material having at least one EUV emitting element, such as xenon (Xe). tin (Sn), or lithium (Li), creating a highly ionized plasma with electron temperatures of several 10's of eV.

[0005] The energetic radiation generated during de-excitation and recombination of these ions is emitted from the plasma in all directions. In one common arrangement, a uear-normai-ineidenee mirror (often termed a "collector mirror" or simply a "collector") is positioned to collect, direct, (and in some arrangements^ focus) the light to a intermediate- location, The- collected light ma then he relayed from the intermediate location to a set of scanner optics and ultimately to a wafer.

[0006} In the EUV portion of the spectrum it is generally regarded as necessary to use reflective optics for the collector. At the wavelengths involved, the collector is advantageously implemented as a multilayer, mirror C'MLM"), As its name implies, this MLM is generally made up of alternating layers of material over a foundation or substrate,

[0007} The optical element must be placed within the vacuum chamber with the plasma to collect and redirect the EUV light. The environment within the chamber is Inimical to the optical element and so limits its useful lifetime, for example, by degrading its reflectivity; it is a high temperature environment. An optical element within the environment may be exposed, to high energy ions or particles of source material. These particles of source material can cause not only physical damage but can also cause localized heating of the MLM surface. The source materials may be- particularly reactive with a material snaking up at least one layer of the MLM. e.g., molybdenum and silicon, so that steps may need to he taken to reduce the potential effects of the reactivity, especially at elevated temperatures, or keep the materials separated. Temperature stability, ion-implantation and diffusion problems may need to be addressed ever, with less reactive source materials, e.g., tin. indium, or xenon.

[0008] Thus, a Collector is an example of the use of an optical element, that must be able to withstand harsh conditions over an extended period of time without

exhibiting appreciable degradation of its optical properties. There are techniques which may be employed to increase optical element lifetime despite these harsh conditions. For example, protective layers or intermediate diffusion barrier layers may be used to isolate the MLM layers from the environment. The collector may be heated to an elevated temperature of, e.g., over 500° C. to evaporate debris from its surface. An etchant may be employed e.g.. a halogen etehant, to etch debris from the collector surfaces and create a. shielding plasma in the vicinity of the reflector surfaces,

[0009] Despite these- techniques., _, there remains a need to extend collector lifetime. With this in mind, applicants disclose arrangements for protecting a optical element operating in a harsh environment designed to extend the useful lifetime of the optical element. SUMMARY

[0010] The following presents a simplified summary of one or more embodiments in order to provide a basic understating of the embodiments. This surriixiary is not an extensive overview of all contemplated embodiments, and is not intended to identify key or critical elements of all embodiments not delineate the scope of any or all embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.

[0011] According to one aspect, the invention, comprises an optical element for reflecting extreme ultraviolet radiation,, the optical element including a stack of alternating layers of at least two dielectric materials a protective layer arranged on an outermost layer of said stack, where the protective lay er comprises- zirconium nitride, ZrN, The protective layer may also, i.e., alternatively, comprise yttrium oxide-, Y3O3. The protective layer may also comprise aluminum oxide, AI1O3 with or without a layer of Si with a naturally occiirring coating of Si(¾. The protective layer may also comprise MoSij with or without a layer -of silicon dioxide, SiCh. The protective layer may also comprise a layer of SIN and a layer of Mo,

10012] The protective layer may also comprise layer Mo and a second layer of

Si with the Si layer having an oute coating of SiCh,

[0013) The optical element may also comprise a substrate, a stack located on the substrate of repeated units of alternating layers of at least two dielectric materials with a at least a subset of the repeated units including an internal protective layer comprising ^• Si _. jN ^' 4. The interna] protective layer may also comprise MoSij. The subset may Include repeated units closer to an external surface of said stack than to the substrate, The optical element may also include an outer protective layer comprising ZrN, The protective layer may also comprise Y2O3,

{00.1.41 In another aspect, the invention comprises apparatus having a source adapted to produce a target of a material in a liquid state, a laser adapted to irradiate said target to change a state of the material from said liquid state to a plasma state to produce BtJV light in an irradiation region, and an optical system adapted to convey said EUV light from said irradiation region to a worfcpiece, in which the optical system comprises an optical element for reflecting extreme ultraviolet radiation, the optical, element comprising alternating layers qf at least two dielectric materials and a protective layer arranged on an outermost layer of said optical element alternating -materials,, wherein the protective coating comprises ZrN. The protective layer may also comprise Y2G3.

(0015] in et another aspect, th invention, comprises a product made using an apparatus which includes a source adapted to produce a target of a material in a liquid state, a laser adapted to irradiate said; target to change a state of the material from said liquid state to a plasma- state to produce EUV light in an irradiation region, and an an optical system adapted to conve said EUV light from said irradiation region to a workpiece, In which the optical system comprises an optical element for reflecting extreme ultraviolet radiation, the optical element comprising alternating layers of at least two dielectric materials- and a protective layer arranged on an outermost layer of said optical element alternating materials, wherein the protective coating, comprises ZrN, The protective layer may also comprise Y2O3,

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows a schematic, not to scale, view of an overall broad conception for a laser-produced plasma EUV light source system according to an aspect of the present invention.

[0017] FIG. 2 is a not-to-seaie diagrammatic cross section through an MLM making up a possible embodiment of the collector 30 of FIG. 1 ,

[0018] FIG. 3 is a no o-scale diagrammatic cross section through an MLM making up another possible embodiment of the collector 30 of FIG. 1 ,

[0019] FIG. 4 is a not-to-scale diagrammatic cross section through an MLM making up another possible embodiment of the collector 30 of FIG. 1.

[0020] FIG. 5 is a not-to-scale diagrammatic cross section through a repeating unit of a stack portion, for a MLM making- up another possible embodiment of the collector 30 of FIG. 1 ,

[0021] FIG. 6 is not-to-scale diagrammatic cross section, through an MLM including the- repeating units of FIG. 5. DETAILED DESCRIPTION

[0022] Various embodiments are now described with reference to the drawings, wherein like reference numerals are use to refer to like elements throughout, in. the following description, for purposes of explanation, numerous specific details are set forth in order to promote a thorough understanding of one or more embodiments. It may be evident in some or all instances, however, that any embodiment described below can be practiced without adopting the specific design details described below, in other instances, well-known structures and devices are shown in block diagram form in order to facilitate description of one or more embodiments..

|0023j With initial reference to FIG. 1 there is shown a schematic view of an exemplary EUV light source, e.g., a laser produced plasma EUV light source 20 according to one aspect of an embodiment of the present invention. As shown , the EUV light source 20 may include a pulsed o continuous laser source 22, which may for example be a pulsed gas discharge CO? laser source producing radiation at 10.6 urn. The pulsed gas discharge€ ⁽ ¾. laser source may have DC or RF excitation operating at high power and high, pulse repetition rate.

10024] The EUV light source 20 also, includes a target delivery system 24 for delivering target material in the form of liquid droplets or a continuous liquid stream. The target material may be made up of tin or a tin compound, although other materials could be used. The target delivery system 24 introduces the target material ^' into the interior of a chamber 26 to an irradiation region 28 where the target material may be irradiated to produce a plasma. In some cases, an electrical charge is placed on the target material to permit the target -material to be steered toward or away from the irradiation region 28. It should be noted that as used herein an irradiation region is a region where target material irradiation may occur, and is an irradiation region even at times when no irradiation is actually occurring,

[0025] Continuing- with FIG. 1. the light source 20 may also include one or more optical elements such as a collector 30. The collector 30 may be a normal incidence reflector, for example, implemented as an MLM, that is, a SiC substrate coated with a Mo Si multilayer with additional thin harrier layers, deposited at each interface to effectively block thermally-induced mterlayer diffusion, The collector 30 may ^' be in the form of a prolate ellipsoid, with an aperture to allow the laser light to pass through and reach the irradiation region 28.· The collector 30. ay be. e.g., in the shape of a ellipsoid that has a first focus at the irradiation region 28 and a second focus at a so-called intermediate point 40 (also called the intermediate ^' focus 40) where the BUV light ma be output from the EUV light source ^' 20 and input to, e.g.. an integrated circuit lithography tool 50 which uses the light, for example, to process a silicon wafer workpiece 52 in a known manner, The silicon wafer workpiece 52 is then additionally processed in a known manner to obtain an integrated circuit device,

|0 26{ As described above, one of th technical challenges in the design of an optical element such as the collector 30 is extending its lifetime. An approach that has been tried to extend collector lifetime is the use of a protective layer made of SiN. This has not been demonstrated to extend collector lifetime sufficiently to prove useful, f 0027] One limitation on collector lifetime is degradation of the coating of the multilayer mirror Caused by bubble formation and delamination under hydrogen attack. One purpose of the protective layer is thus to dissipate the heat that is locally transferred from incident source material (e.g., tin) particles such that the stack does not overheat locally and form blisters. The protective layer has to he thick enough to reduce the heat load received on its surface by the source material particle impact to a Sufficiently low valu when the heat wave has penetrated to the top layers of the Multilayer coating underneath. Therefore, the thickness of the protecti ve layer should preferably be in the range of about .10 nm to about 100 nm, and more preferably be in the range of about 10 nm to about 50 nm, with the lower end of this range being determined by the goal that it be thick enough to reduce the heat load received on its surface and the higher end being determined ^' by the goal of remaining very transparent to 13,5 nm radiation.

(0028} The protective layer materials and structure are chosen such that they are compatible with excited ionic, atomic, and molecular hydrogen and source material, for example, tin. They should dissipate the heat ver we ^' ll without degradation, transmit 13.5 nm EUV light very well and not oxidize unacceptably in the configurations presented. With the protective layer the strong local heating after source material particle impact is dissipated sufficiently within the protective layer so that the stack underneath is at least partially protected from the high-temperature eat wave and therefore does not form blisters, ?

\ Q29) With these goals in mind, ZrN may be used as the material for the protective layer, For this embodiment, the arrangement may have the following structures:

Vacuum

ZrN (protective layer)

Si/Mo (stack)

Substrate

[0030} This arrangement is shown in FIG. 2, which is a not-to-scale diagrammatic cross section through, an MLM making up the collector 30, The collector. 30 is exposed to a vacuum 1.00 in the chamber _. 26. While- referred to as a vacuum here, one of ordinaiy skill in the art will understand -that the vacuum 100 here is a harsh environment, thai is, that ^' it may ^' contain reactive- materials, ions, radicals, -and particles of source material all at elevated temperatures .

(0031] The main body of -the collector 3.0 is an EUV-reflective multilayer coating made up of a repeating stack 1 10 of alternating layers of dielectric material, preferably Si and Mo, made- and configured in a- known manner, arranged on a substrate 120. For example, the stack 1 10 made by made up of a Si/Mb stack of sixty layers, or a. Si/Mo stack, with thin diffusion barrier layers of, e.g. SI3N , between Mo and Si layers, for protection against heat transfer and hydrogen diffusion. For this-and for all embodiments, there may also be a smoothing, layer or interface layer (not shown} between the substrate 120 and the stack 1 10.

[0032] interposed etween the vacuum 100 and the stack 110 is a protective layer 130 exposed to the vacuum 00 and between the vacuum 100 and the stack 110. As described, the protective layer 130 must be thick enough to stop hydrogen ions and radicals from diffusing into the MLM structure. At the same time, the- protective layer 130. must be thin enough that it is sufficiently transparent to EUV radiation. Typically an overall thickness of the protective layer 130 Irs the range of about 1 Onm to about 50 nm satisfies both of these criteria,

0033] A preferred -material ^" or the protective layer 130 in the embod-imentof FIG, 2 is ZrN. ZrN has. been found to be much more, stable than SiN in the source environment it is preferable that a protective laye 1-00 made of ZrN have a thickness in the. range of about 10 urn to about 30. nm, more preferably in the range of about 1.0 nm to about 20 nm. These dimensions are illustrative only and are not limitations on the scope of the invention.

[0034] Another preferred material for the. protective layer 130 in. the embodiment of FIG. 2 is Y2O3. Yttria oxide also has properties that permit it to be stable in the source en vironment. For this embodiment, the arrangement, may have the following structures;

Vacuum

Y;;Oi. (protective layer)

Si/Mo (stack)

Substrate

{0035] It is preferable thai a protective layer 100 made of Υ. ¾ have a thickness in the range of about 10 mn to about 30 nm, m ore preferably w the range of about 10 nm to about 20 nm. These dimensions are illustrative only and are not limitations on the scope of the in vention

[0036] A Oj ma also be used as the material for the protective layer 130. For this embodiment, the arrangement may have the following structures:

Vacuum

AI2O3 (protective layer)

Si/Mo (stack)

Substrate

[0037] It is preferable that a protective layer 130 made of b<¾ have a thickness in the range of about 10 nm to about 30 i n , more preferably in th -range of about 10 nm to about 20 nm, These dimensions are illustrative only and a e not limitations on the scope of the invention.

[0038] Such a protective layer may additionally include a Si sublayer with a

Si<¾ coating developing naturally through oxidation. This -would result in the following structure:

Vacuum

S¾¾ (coating)

Si (sublayer)

A >! (sublayer)

Si/Mo (stack)

Substrate

[0039] The Si sublayer pre erably has a thickness in the range of about 10 nm to about 20· -nm, The Si sublayer will develop a natural oxide coating having a thickness in the range of about 1 am to about 2 ran, These dimensions are illustrative only nd are not limitations on the scope of the invention,.

[0040] As farther regards materials, Mo has a known resistance to hydrogen ernbrit ement. This property makes Mo a suitable protective layer material except that Mo i the sowce-.eiwfconme is unstable because, it is susceptible to oxidation, i.e.., it will form molybdenum oxide. This creates the problem that molybdenum oxide has much higher EUV absorption than Mo so that, the molybdsnuin oxide wiii absorb an unacceptable quantity of the generated radiation it is supposed to reflect. This limits the usefulness of Mo as a material for the protective layer. However, the use of a composite protective layer made up of a sublayer of Mo and a sublayer of another material cap exploit the resistance of Mo to hydrogen embrittlement white minimizing the negative effects of Mo oxidation.

f 0041] Accordingly, in this embodiment, a SIN protective layer is overcoated with an additional thin layer of Mo. The resul ts in the f l lowing structure:

Vacuum

Mo (sublayer)

Si.N (sublayer))

Si/Mo (stack)

Substrate

[0042] This arrangement is shown in FIG. 3, which is a not-to-scale diagrammatic cross section through an MLM making up the collector 30. Interposed between the vacuum 1 0 and the stack 1 10 is a composite protective layer 1 0 made up of n Mo sublayer- 150 exposed to the vacuum 100 and a SIN sublayer 160 between the Mo ..sublayer 1.50 and the stack 1 10. in this arrangement the Mo sublayer 120 will protect SiN sublayer 130 from degradation, while SIM sublayer 130 protects stack 1 10 from hydrogen attack and blister formation.

10943] As described, typically the overall thickness of the protective layer 130 is in the range of about lOnm to about 50 um to stop hydrogen ions and radicals from diffusing into the MLM structure while remaining transparent to EUV radiation, it is preferable that the Mo sublayer 150 have a thickness thai ^' is small enough that reflectivity loss through oxidation of the Mb is acceptable. In a preferred embodiment, the Mo Sublayer 1 SO has a thickness in. the range of about 3 nm to about 10 urn, and even more preferably about 3 mn. The SiN sublayer 160 preferably has a thickness in the range -of about 10 am to about 20 nm. These dimensions are illustrative only and are not limitations on the scope of the invention,

[0Θ44] According to another aspect of the present invention, an MLM is provided, with a composite protective layer thai include a t in layer of Si over a layer .of

Mo. The thin Si layer develops a natural oxide that protects the Mo layer from oxidation. According to this embodiment of the invention, the resulting arrangement may thus have the following, structure:

Vacuum

SiC (coating)

Si (sublayer)

Mo (sublayer)

Si/Mo (stack)

Substrate

[0045] This arrangement is shown in FIG. 4, which is a not-to-seaie

diagrammatic cross section through an MLM making up the collector 30, As in FIG, 3, tHe main body of the collector 30 is a repeating ^' stack. 1.10 of alternating layers of dielectric material, _, preferably Si and Mo. .made and configured in a known manner, arranged on a substrate 120, Interposed between the vacuum 100 and the stack 1.10 is a composite protective layer 140, In the arrangement of FIG, 4, the composite protective layer .140 is made up of an Si. sublayer 170 exposed to the vacuum 100 and aft Mo sublayer 180. between the Si sublayer 170 and the stack 110. The Si sublayer 170 develops a Si(½ coating 190 that protects the Mo layer from oxidation,

[0046] As described, typically the overall thickness of the protective layer 130 Is in the range of about lOnm to about 50 nm to stop hydrogen ions and radicals from diffusing into the MLM structure while remaining transparent to EIJV radiation. It is preferable that the Si sublayer i 70 have a thickness of about 2 nm to about 4 nm. The Mo sublayer I SO preferably has a thickness in the range of about 10 nm to about 20 run. The Si<¾ coating _. 1 _. 90 will have a thickness in the range of about i nm to about 2 nm. These dimensions are illustrative only and are not limitations on the scope of the invention.

[0047] The protective layer 130 may also be made up of a compound that includes Mo. One candidate fo a material for protective layer 130 is molybdenum didlieide, MoSb, MoSij is a hard and oxidation resistant material with a high melting point (— 2030° C) which has outstanding stability at high temperatures, (since Mo and 3 1

Si are in equilibrium, according to the phase diagram). It is also a good barrier to chemical attack and likely also to hydrogen difTusion. It ha& a high thermal conductivity. Its transparency for 13.S am EUV radiation is very high, For example, high temperature multilayer coatings based on MoS¾/Si stacks have shown excellent high temperature and long-term stability properties.

[0048] Si2 layers can be deposited in a highly dispersed way with almost amorphous layer growth. This is a significant advantage compared to the micro- crystalline growth of thick Mo layers.

[00.49] According to this embodiment, of the invention, the resulting

arrange meat ^' may thus have the following structure:

MoSij (protective layer)

Si/Mo (stack)

Substrate

[0050] The MoSij protective layer preferably has a thickness in th range of

^• about 20 nm to about 30 ran. These dimensions are illustrative only and are not.

limitations on. the scope of the invention,

jOOSl] The Mo.S.2 protective layer could also be provided with a SiCfe protective coating. According to this ^' embodiment of the invention, the resulting- arrangement may thus have the following structure:

Si0 ₂ (coating)

MoSi ₂ (protective layer)

Si/Mo (stack)

Substrate

[0052] The SiCb protective coating preferably has a thickness in the range of abotit 1 nm to about 3 nm. The MoSij protective layer preferably has a thickness in the rang of about 20 nm to about 3D run. These diinensions are illustrative only and are not limitations ^' on the scope of the invention.

{00S3J Similar coatings could be done with MojC, NbC or NbSi ₂ in place of

MoSk Another candidate is Mo.jC (molybdenum carbide). Other candidates would be the corresponding niobium compounds. bSi> and NbC. Other carbides or faorides like SiC, ZrC, Zr B _¾ B ₄ C. which are highly transparent. at 13.5 nm could also be considered as a material,

[0054] The stack 110 -may also include internal protective layers as part of some or all of the repeating units (Si/Mo or Si/b/MQ/b) making up the stack 1 10. These internal protective layers may be .used instead, of the protecti ve layer on the exterior of th stack. Thus, the stack 1 10, instead, of having alternating units of Si and Mo for a Si/Mo repeating unit, or equivalent!y a Mo/Si arrangement, would have an. arrangement of Mo/p/Si/p for a repeating unit, with ^M p" representing an internal protective layer. Tins is shown in FIG. 5, which shows a repeating unit 200 made up of a layer of 210 of Mo or Si a layer 220 made up of the other of Mo or Si, and intervening internal protective layer 230. The internal protective layer 230 could be part of each repeating unit 200 or in several outermost repeating units 200 of the stack HO. The interna! protective layer 230 could also prevent hydrogen diffusion and reduces penetration by tin ions and dissipates heat. Since the internal protective 230 is at least in. the outer repeating units of the stack 1 10 it can be sacrificed like the other sublayers,

[0055] Suitable materials for the internal protective layer 230 would be Si ₃ N having a thickness of about 0.8 nm and MoSi ₂ having a thickness of about 1 am. Si ₃ and MoSij layers are presently preferred because of their high stability. Protective layer materials could also be SiC, SiB¾ B ₄ C, NbS¾ Mo and 3N. These layers are all fairly transparent to. EUV radiation at 13.5 nm and serve as barriers for hydrogen diffusion, ion penetration and heat propagation. In most cases the layer growth is amorphous or nearly amorphous.

f00S6] The protecti ve layer thickness is preferably in the range of about 0.4 nm to about 1.2 arn since the preferred thickness of entire repeating unit 200 is about 7 am for a highly reflective multilayer coating for 13.5 nm. The internal protective layer 230 preferably occurs- at least once and more preferably twice in each repeating unit 200, especially in the outer repeating units 200.

[0057] These types of multilayer coatings are compatible with coatin layer erosion. The collector lifetime is extended by the fact thai the essentia! properties of the stack do not change when the sacrificial layers are lost due to erosion, even if this erosion does not occur uniformly.

[0058] If this approach is used, instead of depositing sixty 60 repeating units

200 as the stack, which is sufficien t in case of a coating which is not subject to erosion, it is preferable to use stack with the number of repeating units 200 being in the range of about eighty to about two thousand, This is depicted in FIG 6. which shows the stack 110 made up of repeating un its 200, with the solid dots indicating repetition of no fixed number of repeating units. 00S9] One example would be a stack with about five hundred periods, with each of the periods (or at least the outermost periods) having the structure:

Mo (layer)

S13 (protective layer)

Si (layer)

S15 4 (protective layer)

[0060] In this arrangement, the outmost Mo layer preferably has. a thickness of 3 u , the Si layer preferably has a thickness of 3.5 nra, and the S ^T 4 rotective layers have a thickness of about .8 nm. These dimensions are illustrative only and are not limitations on the scope of the invention.

[0061) Another example would be a stack with about five hundred periods, with each of the periods (or at least the outermost periods) having the structure:

Mo (layer)

MoSij (protective layer)

Si (layer)

MoSia (protective layer)

[0062 j In his arrangement, the outmost Mo layer preferably has a thickness ^' of 3 ma, the Si layer preferably has a thickness of 3,5 nm, and the MoSi ₂ protective layers have a thickness of about 1 am. These dimensions are illustrative only and are not limitations on the scope of the invention.

[0063] It will be apparent to one of ordinary skill in the art that the various protective layers described above can be -applied Using ^' any one of a umbe of known processes such as magnetron sputtering. I t will also be apparent to one of ord inary skill in the art that one or more adhesion layers may included in the disclosed arrangements in. a known manner, for example betwee the substrate and the stack or between the protective layer and the stack. These adhesion layers may be. made, out of any one of number of known materials such as amorphous silicon.

[0064] The above descriptio includes examples of one or more embodiments, it is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either th -detailed description or the claims, such term is intended to be inclusive m a manner similar to the term "comprising" as "comprising" is construed when employed as a transitional word in a claim. Furthermore, although elements of the described aspects and/or embodiments may be described, or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly ^• stated. Additionally, all or a portion of any aspect and/or embodiment may be utilized with ail or a portion of any other aspect and/or embodiment, unless stated otherwise,