Patent Grant
11652119
The invention relates to the field of components for detecting electromagnetic radiation and particularly components for detecting electromagnetic radiation in the infrared wavelength ranges.
Thus, the invention refers to a component for detecting electromagnetic radiation and a method for manufacturing such a component.
In the context of applications for detecting weak electromagnetic signals, such as for components for detecting infrared radiation in space, in order to better identify an effective photon signal versus noise, it is known, in particular from document U.S. Ser. No. 10/326,952, that an opaque mask can be placed over certain detection pixels of these components in order to measure a dark current from said covered pixels.
Thus, with such a configuration described by the document U.S. Ser. No. 10/326,952 for determining the dark current and therefore the noise signal, it is possible to identify the relevant signal emanating from this noise.
However, without further information on the configuration of the mask in the document U.S. Ser. No. 10/326,952, other than that it is possible to provide a mask of a reduced thickness of 1 μm with an adequate material (chromium is mentioned), a mask as described in that document is generally made of metal and is relatively thick, i.e. equal to or greater than 1 μm.
Thus, in the case of a detection component according to a given configuration in which the component comprises a support comprising an active layer in which a plurality of electromagnetic radiation detection structures are made, with the support comprising a first surface from which the active layer extends and a second surface, opposite the first surface, by which the support is intended to receive the electromagnetic radiation, and a mask arranged on the second surface, the following phenomena are observed:
In addition, it should be noted that in the case of low-temperature infrared-radiation detection components, due to the thermal conditions to which they are subjected, they may involve substantial risks of deterioration and delamination for relatively thick opaque masks. In such a use, the use of relatively thin opaque masks should make it possible to limit the risks of deterioration and delamination.
The purpose of the invention is to overcome the above drawbacks, at least in part, and thus aims to provide a detection component which, having the configuration in question, is only partially or even not at all subject to the parasitic reflection phenomena present in the prior art. The invention also aims to provide a detection component capable of having an opaque mask that is less sensitive to deterioration and delamination risks when the component is subjected to low temperatures, particularly in the case of detection components intended to operate at said low temperatures.
To that end, the invention relates to a component for detecting electromagnetic radiation in a wavelength range, comprising:
The opaque mask comprises at least a first, a second, and a third metal, and a transparent material with a refractive index less than or equal to 2 within the wavelength range, the first metal having an extinction coefficient km1 greater than or equal to 5nm1, or even 10nm1, and each of the the second and third metals having an extinction coefficient km2/3 strictly less than 5nm2/3, or even less than or equal to 2nm2/3 with nm1 and nm2/3 being the refractive indices of the first and second and third metals in the wavelength range, with the transparent material having an extinction coefficient kt less than or equal to 0.01.
Starting from the second surface of the support, the opaque mask comprises a successive stack of:
and wherein the second metal layer, the transparent layer, and the assembly of metal elements form MIM structures in the wavelength range.
Thus, according to the invention the extinction coefficients km2 and km3 of the second and third metals may satisfy at least one of the following inequalities with regard to the refractive indices nm2 and nm3 of the second and third metals, respectively:
km2/3<5nm2/3,
km2/3≤4nm2/3,km2/3≤2nm2/3.
Such a combination of MIM structures based on “absorbent” metals, that is, metals having an extinction coefficient km2 strictly less than 5nm2, and a reflective layer based on a “reflective” metal, that is, a metal having an extinction coefficient km1 greater than or equal to 5nm1, makes it possible to take advantage of both the blocking properties provided by the first metal and the first layer made of that metal, and the anti-reflection properties afforded by the MIM structure in the wavelength range. Thus, it is possible to provide a thin mask limiting the shading phenomenon that such a mask could cause, with little or no reflection, thus limiting the risks of parasitic reflection in the nearby environment of the detection component and thus the corresponding spurious signals.
In addition, since such an opaque mask can constitute a relatively thin opaque mask compared to the opaque masks of the prior art, such as the one disclosed in the document U.S. Ser. No. 10/326,952, the opaque mask of a component according to the invention entails relatively low risks of deterioration and delamination when the component is subjected to low temperatures.
Note that a metal is characterized by an electric permittivity ε=(n+ik)2, where n is the refractive index of said metal and k is the extinction coefficient. Based on this value, it is possible to calculate a skin depth δ at a given wavelength λ using the following equation: δ=λ/(2πk).
The MIM (Metal-Insulator-Metal) structures are horizontal multilayer cavities used in particular for antennas. An MIM structure comprises a first metal layer covered with a transparent layer, generally dielectric, and a metal element, such as a metal bump, preferably made of the same metal as said first metal layer. In the conventional application of such MIM structures, in which cavity resonances that are relatively selective in terms of wavelength are used, the metal of the first metal layer and the assembly of metal elements is a metal having good reflectivity, i.e. a metal for which the extinction coefficient in the wavelength in question is greater than 10 times the refractive index of this same metal at the wavelength in question. More information on such MIM structures can be found in the article published in 2006 by A. P. Hibbins and his co-authors, in the scientific journal “Physical Review B,” Number 74, Pages 073408.
The second and third metals may be identical.
With such a configuration, the absorption rate of the MIM structure is optimized.
The first metal layer may have a thickness hm1 more than 2 times greater than a skin depth δm1 of the first metal in the wavelength range, with the thickness of the first metal layer preferably being more than 4 times greater than the skin depth δm1 of the first metal in the wavelength range.
In this way the opaque mask has a particularly low or even substantially zero transmission rate.
The second metal layer may have a thickness hm2 of between 0.5 times a skin depth δm2 of the second metal in the wavelength range and 4 times the skin depth δm2 of the second metal in the wavelength range, with the thickness of the first metal layer preferably being more than 4 times greater than the skin depth δm1 of the first metal in the wavelength range.
Within a plane substantially parallel to the second surface, the metal elements may have at least one lateral dimension L equal to or less than a value Lm satisfying the following equation:
where Δ0 is a central wavelength within the wavelength range, nd is a refractive index of the transparent material at said central wavelength, hd is a thickness of the transparent layer, and δm2 is a skin depth of the second metal at said wavelength,
the metal elements preferably have a maximum lateral dimension and a minimal lateral dimension within a plane substantially parallel to the second surface, of between 0.75 times said value Lm and 1.25 times the value Lm.
The MIM structures are thus particularly well-suited to the wavelength range.
In the assembly of metal elements, two adjacent metal elements have an inter-barycentric distance between them that is less than or equal to λ0/nd, with λ0 being a central wavelength of the wavelength range and nd being the refractive index of the transparent material in the wavelength range, with the pitch P between two adjacent metal elements in the assembly of metal elements preferably being less than 0.75 times Δ0/nd.
The metal elements of the assembly of metal elements may be arranged periodically with a pitch P between the metal elements of less than Δ0/nd, said pitch P between the metal elements preferably being less than 0.75 times λ0/nd.
The transparent layer may have a thickness of between λ0/4nd and λ0/50nd, inclusively, with λ0 being a central wavelength within the wavelength range and nd being the refractive index of the transparent material in the wavelength range.
The thickness of the transparent layer may be between λ0/4nd and λ0/25nd, inclusively.
Each metal element of the assembly of metal elements may have a thickness in the stacking direction of the opaque mask that is between one times a skin depth δm2 of the third metal in the wavelength range and three times said skin depth δm2 of the second metal, with the thickness of each metal element preferably being between one and a half times the skin depth δm2 of the third metal in the wavelength range and two and a half times said skin depth δm2 of the third metal.
With such parameters of the MIM structures, the reflection rate of the opaque mask is particularly low or even substantially zero.
The opaque mask may be arranged on the second surface of the support to block the electromagnetic radiation for the at least one masked structure and the detection structures adjacent to said at least one masked structure.
With such an arrangement, the potential collection of photo-carriers from the adjacent structures to the masked structure, which could occur as a result of the typical electrical cross-talk between adjacent pixels, is limited.
The opaque mask may be arranged on the second surface of the support to also block the electromagnetic radiation for the detection structures adjacent to said detection structures adjacent to said at least one masked structure.
With such an arrangement, the potential risk of collecting photo-carriers from the adjacent structures is substantially zero.
The support may have a thickness of less than 10 μm, with the opaque mask extending, on either side of a projection of the masked structure, on the second surface of the support over a distance greater than 15 μm and preferably greater than 30 μm.
The detection structures of the plurality of detection structures may be arranged according to a matrix defining detection structure rows and columns, the opaque mask is arranged to block the electromagnetic radiation for des detection structures of the same row or column.
The invention furthermore relates to a method for manufacturing a component for detecting electromagnetic radiation in a wavelength range, said method comprising the following steps:
the opaque mask being arranged on a portion of the second surface of the support to block the electromagnetic radiation for at least one of the detection structures, called a masked structure,
in which method the opaque mask comprises the first, the second, and the third metal and the material, called a transparent material, with the first metal having an extinction coefficient km1 greater than or equal to 5nm1, or even 10nm1, and each of the second and third metals having an extinction coefficient km2/3 strictly less than 5nm2/3, or even less than or equal to 2nm2/3 with nm1 and nm2/3 being the refractive indices of the first and each of said second and third metals in the wavelength range, the transparent material having an extinction coefficient kt less than or equal to 0.01.
Such a method makes it possible to manufacture a detection component according to the invention and to obtain the associated advantages.
The formation step consists of the following sub-steps:
During the opaque mask formation step, the mask is arranged on the second surface of the support to block the electromagnetic radiation for the at least one masked structure and the detection structures adjacent to said at least one masked structure.
In this way, a component manufactured with such a method provides, in operation, a masked structure that has little or even no exposure to leakage currents that could be generated by the adjacent structures if they are subjected to electromagnetic radiation.
The present invention will be more readily understood from a reading of the description of embodiments, given purely as examples and not intended to limit in anyway, in reference to the appended drawings, in which:
Identical, similar, or equivalent parts of the various figures have the same numerical references so as to facilitate the reading of the various figures.
In an effort to make the figures more legible, the various parts in the figures are not necessarily shown according to a uniform scale.
The various possibilities (variants and embodiments) must be understood as not being exclusive of each other, and may therefore be combined.
Such a detection component 1, according to a main embodiment of the invention, is more specifically intended for the detection of electromagnetic radiation in the infrared wavelength range. Thus, the various values indicated in the embodiments described below refer to this practical application, in which the targeted wavelength range is in a mid-infrared wavelength range, for example a wavelength range of between 2.5 and 3.5 μm. Naturally, based on the disclosure herein, a person skilled in the art is perfectly capable of adapting these values in order to achieve an optimized detection of electromagnetic radiation in a wavelength range other than the infrared, by using such a detection structure 10. Thus, the invention is particularly advantageous in the context of applications for detecting electromagnetic radiation in the infrared wavelength ranges based on the detection components operating at low temperatures, that is, typically less than −100° C. or 173 K, most commonly around 80 K as in the case of HgCdTe-based detectors.
Such a detection component 1 includes:
As shown in
The second metal layer 142, the transparent layer 143, and assembly of metal elements 144 form MIM structures in the wavelength range.
The first metal has an extinction coefficient km1 greater than or equal to 5nm1 and the second metal has an extinction coefficient km2 strictly less than 5nm2, or even less than or equal to 2nm2, with nm1 and nm2 being refractive indices of the first and of the second metal in the wavelength range. Preferably, the first metal has an extinction coefficient km1 greater than or equal to 10nm1.
Note that according to one possibility of the invention, the second metal may have an extinction coefficient km2 that is less than or equal to 4nm2.
In this first embodiment, the first support 110 is a cadmium telluride and zinc CdZnTe, the first support 110 comprising the active layer 120 made of a mercury cadmium telluride, HgCdTe. Each detection structure 121A, 121B, 122, and 123 consists, for example, of a PN photodiode comparable to those implemented in the prior art, which are only shown by their respective volume footprints on the active layer.
Naturally, while each detection structure 121A, 121B, 122, and 123 is a PN photodiode in this first embodiment, the invention is not limited to this sole type of detection structure. Thus, the component may, for example, comprise another type of photodiode, such as a PiN photodiode (i.e. a photodiode having an intrinsic area made between an N area and a P area), a zener diode, or a barrier diode, without the scope of the invention being exceeded.
The support 110 may have a thickness between 1 and 20 μm, preferably between 5 and 15 μm. Thus, the support can therefore have a thickness of 10 μm, for example.
The second surface of the support 110 may comprise an anti-reflective coating 130 according to the customary practice of a person skilled in the art, in the context of the detection components 1 from the prior art. Note that in the present embodiment, as shown in
The opaque mask 140 is arranged on the second surface of the support 110 to block the electromagnetic radiation for at least one of the masked detection structures. In order to perfect such a block, as shown partially in
As part of an application of the invention in the near infrared and mid-infrared, the first metal layer 141 may be made of gold Au, aluminum Al, or copper Cu, or even an alloy of two metals, or even an alloy of these three metals.
Note that, especially if the first metal is gold Au a bonding layer of a few nanometers may be provided between the second surface of the support 110 and the first metal layer 141. Such a bonding layer may be made of Titanium Ti or nickel Ni for the first metal, which is gold Au.
The first metal layer 141 preferably has a thickness hm1 more than 2 times greater than a skin depth δm1 of the first metal in the wavelength range, with the thickness of the first metal layer 141 preferably being greater than or equal to 4 times skin depth δm1 of the first metal in the wavelength range. Note also that the thickness of the first metal layer is preferably less than 10δm1.
In other words, thickness hm1 of the first metal layer preferably satisfies the inequality 2δm1<hm1<10δm1 and, in a particularly advantageous way, satisfies the following inequality:
4δm1≤hm1<2δm1 (2)
For instance, thickness hm1 may be substantially equal to 4δm1. In the event that the first metal is gold Au, gold having a refractive index of 1.24, an extinction coefficient of 15.7, and therefore a skin depth δm1 of 25 nm at a wavelength of 2.5 μm, a first metal layer 141 with a thickness of 100 nm is therefore obtained.
As part of an application of the invention in the near infrared and mid-infrared, the second metal layer 142 may be made of titanium Ti or platinum Pt or tungsten W or even an alloy of titanium and tungsten.
The second metal layer 142 has a thickness hm2 of between a 0.5 times a skin depth δm2 of the second metal in the wavelength range, and 4 times the skin depth δm2 of the second metal in the wavelength range. In other words, the thickness of the second metal layer 142 satisfies the following equation:
0.5δm2≤hm2≤2δm2 (3)
For example, thickness hm2 may be on the order of the skin depth of the second metal. In the event that the second metal is titanium Ti, the titanium Ti has, at a wavelength of 2.5 μm, a refractive index nm2 of 4.36 and an extinction coefficient km2 of 3.19, and therefore a skin depth δm2 of the titanium of 130 nm, a second metal layer 141 on the order of 130 nm, that is, between 100 nm and 160 nm, is therefore obtained.
The transparent layer 143 is made of a material, called a transparent material, with a refractive index equal to or less than 2 in the wavelength range and having an extinction coefficient kt less than or equal to 0.01 in the wavelength range. In a typical configuration of the invention, the layer of transparent material is made of a dielectric material, such as a silicon dioxide SiO2, alumina Al2O3, and magnesium fluoride MgF2. As a variant, the layer of the transparent material 143 may be made of a conductive oxide, such as an indium tin oxide, more commonly known by the acronym ITO, a zinc oxide, more commonly known by the acronym ZnO, and an aluminum-doped zinc oxide, more commonly known by the acronym AZO. The assembly of these materials has an extinction coefficient kt less than or equal to 0.01 in the wavelength range.
Note that the material of the transparent layer 143 preferably has a refractive index less than or equal to 1.5, which is particularly the case for silicon dioxide SiO2, alumina Al2O3, and magnesium fluoride MgF2.
The transparent layer 143 may have a thickness Epd of between λ0/4nd and λ0/50nd, inclusively, with λ0 being a central wavelength within the wavelength range and nd being the refractive index of the transparent material 143 in the wavelength range. In other words, thickness Epd of the transparent layer 143 may satisfy the following inequalities:
For instance, thickness Epd of the transparent layer 143 may be equal to λ0/10nd.
In the same way, the transparent layer 143 may have a thickness Epd of between λ0/4nd and λ0/25nd, inclusively.
The assembly of the metal elements 144 is arranged on third layer 143 and is made of the second metal. Each metal element 144 of said assembly occurs in the form of a metal bump that may assume, for example, a square or circular shape or even a hexagonal shape, according to a projection onto the second surface of the support 110.
Each metal element 144 preferably has, in a plane parallel to the second surface, at least one lateral dimension Lem such that, for the metal elements 144 having a square projection onto the second surface of the support, a length of one side of said square, for the metal elements 144 having a circular projection onto the second surface of the support, a diameter of said circle, which is preferably less than or equal to a value Lm satisfying the following equation:
where λ0 is a central wavelength of the wavelength range, nd is a refractive index of the transparent material at said central wavelength, hd is the thickness of the transparent layer, and δm2 is the skin depth of the second metal at said central wavelength.
Note that, in a particularly advantageous way, the metal elements 144 have a maximum lateral dimension and a minimal lateral dimension in the plane substantially parallel to the second surface, both of which are between 0.75 times the value Lm and 1.25 times the value Lm.
According to a first possibility of the invention, the metal elements may have a non-periodic arrangement with a spacing between two adjacent metal elements preferably having a pitch P that is less than or equal to λ0/nd, where λ0 is a central wavelength of the wavelength range and nd is the refractive index of the transparent material in the wavelength range. In a particularly advantageous way, the pitch P between the two adjacent metal elements 144 in the assembly of the metal elements 144 is less than 0.75 times λ0/nd.
According to a second possibility of the invention, the metal elements 144 may have a periodic arrangement with a lattice pitch P that is less than or equal to λ0/nd, the lattice pitch preferably being less than 0.75 times λ0/nd. Note that according to this second possibility, the metal elements may be arranged in a square lattice with the lattice pitch P.
Note that in the case of a second non-noble metal such as Titanium Ti in order to limit the risk of oxidizing, according to a possibility not shown, a passivation layer of a few nanometers may be deposited on the metal elements 144. For instance, for a second metal consisting of titanium Ti the metal elements 144 may be covered with a passivation layer of silicon nitride SiN, or zinc sulfide ZnS at a thickness of between 5 and 30 nm. Such a passivation layer may therefore have a thickness of 10 nm, for example.
In addition, when selecting the first and second metals and the transparent material for applications of a detection component 1 cooled to a relatively low temperature, i.e. typically less than −100° C. or 173 K, these materials may be chosen to have comparable thermal expansion coefficients. According to this possibility, the first metal may be platinum Pt the second metal titanium Ti and the transparent material may be an amorphous silicon dioxide a-SiO2 these materials having a thermal expansion coefficient on the order of 9.10−6 K−1.
As a variant to the present embodiment, the metal elements may be made of a third metal. According to this variant, the third metal, as in the case of the second metal, is chosen so as to have an extinction coefficient km3 that is less than or equal to 2nm3, with nm3 being the refractive index of the third metal in the wavelength range. Thus, as part of an application of the invention in the near infrared and mid-infrared, the third metal may be titanium Ti, or platinum Pt, or tungsten W, or even an alloy of titanium and tungsten.
Thus, in a practical example of this first embodiment, for a wavelength range centered around a central wavelength Δ0 of 2.7 μm, the opaque mask 140 may have the following properties:
The simulations of such an opaque mask 140 conducted by the inventors using the Rigorous Coupled-Waves Analysis (RCWA) show that such a mask has, as shown in
In order to demonstrate the small variation in the reflectivity R of such an opaque mask 140 with the angle of incidence of the electromagnetic radiation λ,
One can thus see that in the wavelength range going from 2.45 μm to 3.1 μm, the reflectivity remains below 0.02, and this regardless of the polarization and incidence of the electromagnetic radiation.
In addition, it is possible to optimize the opaque mask 140 to obtain a larger wavelength range for which the reflectivity remains below 5%. For instance, if we take the opaque mask 140 from the previous example, in which the metal elements 144 have a lateral dimension Lem equal to 500 nm, a thickness hem equal to 225 nm, and a lattice pitch P of 1.1 μm, and the transparent layer 143 has a thickness hd of 140 nm, it is possible to obtain, in keeping with the inventors' simulations, a variation of the reflectivity 211 as illustrated in
In addition, it is possible to optimize the opaque mask 140 to obtain a larger wavelength range for which the reflectivity remains below 5%. For instance, if we take the opaque mask 140 from the previous example, in which the metal elements 144 have a lateral dimension Lem equal to 500 run, a thickness hem equal to 225 nm, and a lattice pitch P of 1.1 μm, and the transparent layer 143 has a thickness hd of 140 nm, it is possible to obtain, in keeping with the inventors' simulations, a variation of the reflectivity 214 as illustrated in
According to the invention, and to avoid any optical leakage in the masked structure, which could originate from diffraction phenomena associated with the edges of the opaque mask 140, it is possible to arrange the opaque mask 140 on the second surface of the support 110 to block the electromagnetic radiation λ for the at least one masked structure and certain detection structures adjacent to the said at least one masked structure. Such a possibility also makes it possible to limit the leakage current phenomena which may occur in such a detection component 1 between the detection structures, and which could therefore interfere with the noise signal measured by the masked structure.
To illustrate this phenomenon, as shown in
It is therefore clear that, for a support 110 made of cadmium telluride and zinc CdZnTe, with a thickness of 10 μm, i.e. with a ratio of the support thickness to the refractive index of 7.5, the directly adjacent structures and the structures that are adjacent to them must also be covered by the opaque mask 140 to achieve an absorption of less than 0.1%.
Thus, in keeping with the calculations made by the inventors, it is possible, in the case of a detection component 1 comprising a support that is 10 thick and with an opaque mask 140 extending on either side of a projection of the masked structure on the second surface over a distance greater than 30 μm (that is, two adjacent pixels of 15 μm per side), for a distance greater than 15 μm, this absorption remains less than 0.1%. With this same support thickness, for such a distance greater than 15 μm (that is, a single adjacent pixel of 15 μm per side), this absorption remains under 0.15%.
According to the first example shown in
According to the second preferred example shown in
A detection component 1 according to this first embodiment may be made using a method comprising the following steps:
Note that the step for forming assembly of metal elements 144 may comprise a sub-step for depositing a fourth layer of the second metal with a thickness hem, and a localized etching sub-step, for example by optical lithography, to only keep the parts of the fourth layer corresponding to the metal elements 144.
According to a first and a second variant of this main embodiment of the invention, illustrated in
In such an arrangement, with metal element 144 being part of both the first MIM structure 151, in accordance with the teaching of this document and the main embodiment, as well as the second MIM structure 152, in accordance with these first and second variants, a stacking of the resonant cavities of these first and second MIM structures 151, 152 is achieved. The cavities corresponding to the second MIM structures 152 have lateral dimensions that are less than or equal to those corresponding to the first MIM structures 151, since the lateral dimensions of the cavities of the second MIM structures 152 correspond to the lateral dimensions of the portions of the fourth transparent layer 145.
As discussed below in reference to
Thus, taking the first variant of this first embodiment shown in
Note, in addition, that in this first variant the portion of the fourth transparent layer 145 and the portion of the fifth metal layer 146 extend corresponding the metal element 144 and, thus, have lateral dimensions that are identical to those of said metal element 144. The respective thickness of the fourth transparent layer 145 and of the fifth metal layer may be determined in a similar way to the thickness of the third transparent layer 143 and of the metal elements 144, respectively, and may be adjusted to optimize the wavelength range. Thus, if according to one possibility of this first variant the fourth transparent layer 145 may have a thickness identical to that of the third transparent layer 143, it is also perfectly conceivable that the fourth transparent layer 145 can have a greater thickness than that of the third transparent layer 143, with the latter preferably remaining greater than or equal to λ0/50nd or even λ0/25nd.
Thus, according to an embodiment example of this first variant, the opaque mask 140 may have the following properties:
It can be seen from this graph that such a first variant (curve 232) makes it possible to achieve a relatively extensive wavelength range, since it goes from approximately 9.50 μm to approximately 13 μm, compared to a wavelength range obtained for an opaque mask 140 according to the main embodiment (curve 231), which goes from about 10.2 μm to about 10.8 μm.
A detection component 1 according to this first variant of the main embodiment may be made by means of a manufacturing method that differs from a method for manufacturing a detection component 1 according to the first main embodiment in that, when assembly of the metal elements 144 is being made, there is a step for forming the fourth transparent layer 145 and the fifth metal layer 146 on a metal layer made of the third metal intended to form the metal elements 144, and a step for localized etching of the fifth metal layer 146, of the fourth transparent layer 145, and of the metal layer made of the third metal in order to laterally delimit the metal elements, the portions of the fourth transparent layer 145, and the portions of the fifth metal layer 146.
According to the second variant of the main embodiment of the invention, shown in
So, a detection component 1 according to this second variant of the first embodiment differs from a detection component 1 according to the first variant of the first embodiment in that, for each metal element 144, the portion of the corresponding fourth transparent layer 145 and the portion of the corresponding fifth metal layer 146 have lateral dimensions that are less than that of the said metal element 144.
The method for manufacturing a detection component 1 according to this second variant of the first embodiment differs from the method for manufacturing a detection component 1 according to the first variant of the first embodiment in that the step for localized etching of the fifth metal layer 146, of the fourth transparent layer 145, and of the metal layer made of the third metal is conducted in two parts, one for a local etching of the fourth transparent layer 145 and of the fifth metal layer, and the other for a local etching of the layer of the third metal. Such a local etching in two parts provides, for each metal element 144, a portion of the fourth transparent layer 145 and a portion of the fifth metal layer 146 with smaller dimensions than those of the fourth transparent layer.
Note that if, in the first embodiment of the invention and in the first and second variants of the first embodiment, the second metal layer 142 and the metal elements 144 are made of the second metal, it is still conceivable that opaque mask 140 may comprise a third metal and that the metal elements may be made of the third metal, without exceeding the scope of the invention. Such a third metal will then have an extinction coefficient km3 strictly less than 5nm3, or even less than or equal to 2nm3, where nm3 is the refractive index of the third metal in the wavelength range. Likewise, if, in the first and second variants of the main embodiment, the fourth transparent layer 145 is made of the transparent material, it is also conceivable, and without exceeding the scope of the invention, that the fourth transparent layer 145 may be made of a second transparent material, with the understanding that the second material will have a refractive index less than or equal to 2 in the wavelength range. Similarly, if, in the first and second variants of the main embodiment, the fifth metal layer 146 is made of the second metal, it is also conceivable, and without exceeding the scope of the invention, that fifth metal layer 146 may be made of a fourth metal. Such a fourth metal will then preferably have an extinction coefficient km4 strictly less than 5nm4, or even less than or equal to 2nm4, where nm4 is the refractive index of the fourth metal in the wavelength range.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19 15735 | Dec 2019 | FR | national |
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| Number | Date | Country |
|---|---|---|
| WO 2019004319 | Jan 2019 | WO |
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| Number | Date | Country | |
|---|---|---|---|
| 20210199863 A1 | Jul 2021 | US |
