WO2022064129A1

WO2022064129A1 - Method for applying a material comprising a stack with absorbent metallic layer and dielectric topcoat, and this material

Info

Publication number: WO2022064129A1
Application number: PCT/FR2021/051608
Authority: WO
Inventors: Denis Guimard; Johann SKOLSKI; Nadia ZENID
Original assignee: Saint-Gobain Glass France
Priority date: 2020-09-22
Filing date: 2021-09-21
Publication date: 2022-03-31
Also published as: EP4217324A1; FR3114264A1

Abstract

The invention concerns a method for applying a material comprising a substrate (30) coated on one face (29) with a stack of thin layers (14) comprising at least one metallic functional layer (140) and an anti-reflection coating (160) situated above said functional layer (140) on the opposite side from said substrate (30) which finishes with: - a metallic layer (168), said metallic layer (168) having a physical thickness of between 1.0 and 8.0 nm, or even between 1.5 and 5.0 nm, or even between 1.8 and 2.5 nm; and then - a dielectric topcoat (169) which is situated on and in contact with said absorbent metallic layer (168).

Description

DESCRIPTION

METHOD FOR DEPOSITING A MATERIAL COMPRISING A STACK WITH AN ABSORBENT METALLIC LAYER AND A DIELECTRIC OVERLAYER AND THIS MATERIAL

The invention relates to a material and its deposition process, this material comprising a substrate coated on one face with a stack of thin layers with reflection properties in the infrared and/or in solar radiation comprising at least one metallic functional layer , in particular based on silver or on a metal alloy containing silver and at least two antireflection coatings, said antireflection coatings each comprising at least one dielectric layer, said functional layer being placed between the two antireflection coatings.

In this type of stack, the single, or each, metallic functional layer is thus disposed between two antireflection coatings each generally comprising several layers which are each made of a dielectric material of the nitride type, and in particular silicon nitride or aluminum, or oxide. From the optical point of view, the purpose of these coatings which frame the or each metallic functional layer is to "anti-reflect" this metallic functional layer.

It is known from international patent application No. WO 2010/142926 to apply a treatment by radiation after the deposition of a stack comprising a functional layer to reduce the emissivity or improve the optical properties of this stack, by providing in particular an absorbent layer in the terminal layer of the stack. The use of an absorbent terminal layer makes it possible to increase the absorption of radiation by the stack and to reduce the power required for treatment. As the terminal layer oxidizes during treatment and becomes transparent, the optical characteristics of the stack after treatment are interesting (high light transmission can in particular be obtained).

This radiation treatment of the stack does not structurally modify the substrate. As it is essential to have a expression to designate such a treatment of the stack without structural modification of the substrate, it is customary to use the expression "treatment of the stack of thin layers using a source producing radiation" to mean that it is only the stacking that is affected by the processing; even if the substrate is present during the treatment because the stack must be on a support.

It is also known from international patent application No. WO 2016/051069 to apply a radiation treatment after the deposition of a stack comprising a metallic terminal layer consisting of zinc and tin, in Sn _x Zn _y with a ratio of 0.1 < x/y < 2.4 and having a physical thickness between 0.5 nm and 5.0 nm excluding these values.

The treatments are generally carried out by scrolling the substrate through an enclosure. It is desired that the substrate pass as quickly as possible because the productivity of the line increases with the speed but this speed must not be too high for the treatment to actually produce the desired effect. Also, too slow a speed can damage the stack of thin layers.

The invention is based on the discovery of a particular configuration of two layers terminating the stack opposite the substrate which makes it possible to reduce the resistance per square measured after treatment at the same speed of treatment by radiation of the stack according to the techniques known, or to increase the rate of radiation treatment of the stack according to known techniques while maintaining the resistance per square measured after treatment.

An object of the invention is thus to achieve the development of a new type of stack of layers with one or more functional layers, a stack which has, after rapid treatment of the stack by radiation, a low resistance per square ( and therefore low emissivity), high light transmission (and therefore low light absorption), as well as high mechanical durability.

In the particular configuration according to the invention, it is proposed to finish the stack, opposite the face of the substrate which carries it, with two layers: a metallic, absorbent layer, then a dielectric overlayer comprising oxygen so that this dielectric overlayer can both:

- constitute an oxygen reservoir to allow the oxidation of the absorbent metal layer located just below during the heat treatment;

- contributing to the mechanical durability of the stack;

- and contribute to obtaining a high light transmission, as well as obtaining a homogeneity of appearance, both in transmission and in reflection.

The subject of the invention is thus, in its broadest sense, a process for depositing a material according to claim 1. The dependent claims present advantageous versions.

The method comprises: a)- the deposition on one face of said glass substrate, of the stack of thin layers, then b)- the treatment of said stack of thin layers using a source producing radiation and in particular radiation infrared, and preferably the treatment of said stack of thin layers using a source producing laser radiation.

The material comprises a glass substrate, coated on one side with a stack of thin layers with reflection properties in the infrared and/or in solar radiation comprising at least one, or even just one, metallic functional layer, in particular base of silver or metal alloy containing silver and at least two antireflection coatings, said antireflection coatings each comprising at least one dielectric layer, said functional layer being placed between the two antireflection coatings, said material being remarkable in that , before the treatment of step b), said stack deposited in step a), opposite said substrate, ends starting from the substrate by:

- an absorbent metal layer, with a physical thickness of said metal layer which is between 1.0 and 8.0 nm, or even between 1.5 and 5.0 nm, or even between 1.8 and 2.5 nm; then

- a dielectric overlayer comprising oxygen, which is located on and in contact with said absorbent metallic layer with a physical thickness of said dielectric overlayer which is between 1.5 and 40.0 nm, or even between 2.6 and 35.0 nm, or even between 5.6 and 30.0 nm.

Said treatment of step b) is preferably carried out in an atmosphere not comprising oxygen.

Said dielectric overlayer is thus located on and in contact with said absorbent metal layer and the stack does not include any other layer further from the surface of the substrate than said dielectric overlayer comprising oxygen.

Said dielectric overlayer comprising oxygen preferably has a physical thickness which is between 5.6 and 25.0 nm, or even between 6.6 and 20.0 nm, or even between 7.6 and 15.0 nm, in order to increase mechanical durability.

Said absorbent metal layer preferably comprises at least one element chosen from Sn, Zn, Ti, In, Nb; it may consist of Sn, or Zn or Ti, or In, or Nb or a mixture of Sn and Zn, or a mixture of Sn and In.

Said dielectric overlayer preferably comprises at least one element chosen from Sn, Zn, Ti, Si, Zr.

Preferably, said dielectric overlayer is an oxide dielectric overlayer, or consisting of oxide of one or more elements, in order to maximize the oxidation effect on the absorbent metal layer during the treatment; as usual, "oxide" means that the layer (here the overlayer) does not contain nitrogen.

In a variant, this dielectric overlayer consists of an oxide having a composition which is the stable stoichiometry of the metallic element present or of the metallic elements present if there are several. It can be for example TiCh, ZrC, SiC, ZnO, SnC.

In another variant, this dielectric overlayer consists of an oxide having a composition which is over-stoichiometric in oxygen with respect to the stable stoichiometry of the metallic element present or of the metallic elements present if there are several. It can be for example TiOx, ZrO _x , SiO _x , SnO _x , with x > 2.

Preferably, this dielectric overlayer does not consist of an oxide having a composition which is substoichiometric in oxygen with respect to the stable stoichiometry of the metallic element present or of the metallic elements present if there are several.

In a variant, said antireflection coating located under said metallic functional layer and/or said antireflection coating located above said metallic functional layer comprises a dielectric layer comprising nitrogen, preferably a dielectric layer of silicon-based nitride.

Preferably, said anti-reflective coating located under said functional layer comprises towards said substrate:

- a sub-layer of zinc-based oxide, ZnO, which is located under and in contact with said functional layer, with a physical thickness of said sub-layer of zinc-based oxide ZnO which is between 0, 3 and 9.0 nm, even between 1.0 and 7.0 nm, even between 1.5 and 5.0 nm; and

- a dielectric sub-layer of titanium-based oxide, TiOz, which is located under and in contact with said sub-layer of zinc-based oxide ZnO, with a physical thickness of said sub-layer of oxide at titanium base, TiOz, which is between 10.0 and 50.0 nm, or even between 15.0 and 45.0 nm, or even between 20.0 and 45.0 nm.

Preferably, said anti-reflective coating located above said functional comprises, opposite said substrate and under said absorbent metal layer:

- a layer of zinc-based oxide, ZnO, with a physical thickness of said layer of zinc-based oxide ZnO which is between 2.0 and 10.0 nm, or even between 2.0 and 8.0 nm, or even between 2.5 and 5.4 nm; and

- a silicon-based nitride dielectric layer, SisN/j.

In a specific variant, said antireflection coating located above said functional layer further comprises a dielectric intermediate layer located between said ZnO zinc-based oxide overlayer and said silicon-based nitride dielectric layer, this dielectric intermediate overlayer being oxidized and preferably comprising a titanium oxide.

Said stack comprises a single metallic functional layer or may comprise two metallic functional layers, or three layers metallic functional layers, or four metallic functional layers; the metallic functional layers in question here are continuous layers.

Said metallic functional layer, or each metallic functional, preferably has a physical thickness which is between 7.2 and 22.0 nm, or even between 9.0 and 16.0 nm, or even between 10.6 and 14.4 nm , or even between 9.5 and 12.4 nm. The range of 7.2 and 9.5 nm, or even of 7.2 and 8.5 nm may be particularly appropriate for a stack with a single metallic functional layer and high light transmission.

A metallic functional layer comprises, preferably, predominantly, at least 50% in atomic percentage, at least one of the metals chosen from the list: Ag, Au, Cu, Pt; one, several, or each, metallic functional layer is preferably silver.

By “metallic layer” within the meaning of the present invention, it should be understood that the formulation of the composition of the layer does not contain oxygen or nitrogen.

By "absorbing layer" within the meaning of the present invention, it should be understood that the layer is a material having an n/K ratio over the entire visible wavelength range (from 380 nm to 780 nm) between 0 and 5 excluding these values and having an electrical resistivity in the bulk state (as known in the literature) greater than 10' ⁵ Ω.cm.

It is recalled that n designates the real refractive index of the material at a given wavelength and k represents the imaginary part of the refractive index at a given wavelength; the ratio n/k being calculated at a given wavelength identical for n and for k.

By "metallic absorbent layer" within the meaning of the present invention, it should be understood that the layer is absorbent as indicated above and that the formulation of the composition does not contain any oxygen atom, nor any atom of nitrogen.

As usual, by "dielectric layer" within the meaning of the present invention, it should be understood that from the point of view of its nature, the layer is "non-metallic", that is to say that it comprises oxygen or nitrogen, or both. In the context of the invention, this term means that the material of this layer has an n/k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. It is recalled that n denotes the real refractive index of the material at a given wavelength and the coefficient k represents the imaginary part of the refractive index at a given wavelength, or absorption coefficient; the ratio n/k being calculated at a given wavelength identical for n and for k.

By "in contact" is meant in the sense of the invention that no layer is interposed between the two layers considered.

By "based on" is meant within the meaning of the invention that for the composition of this layer, the reactive elements oxygen, or nitrogen, or both if they are both present, are not considered and the non-reactive element (eg silicon or zinc) which is indicated as constituting the base, is present at more than 85 atomic % of the total non-reactive elements in the layer. This expression thus includes what is commonly referred to in the technique under consideration as "doping", whereas the doping element, or each doping element, may be present in a quantity ranging up to 10 atomic %, but without the total dopant does not exceed 15 atomic % of the non-reactive elements.

In a particular variant, said antireflection coating located under said functional layer does not include any layer in the metallic state. In fact, it is not desirable for such a layer to be able to react at this location, and in particular to oxidize, during the treatment.

In a particular variant, said antireflection coating located under said functional layer does not include any absorbent layer. In fact, it is not desirable for such a layer to be able to react at this location, and in particular to oxidize, during the treatment.

It is all the more surprising to achieve the properties targeted by the invention for these two previous variants because similar properties are sometimes obtained in the prior art with these two previous variants.

Preferably, said S13N4 silicon-based nitride dielectric layer does not include zirconium.

Preferably moreover, said dielectric layer of nitride based on silicon SI-3N4 does not comprise oxygen. The present invention also relates to multiple glazing comprising a material according to the invention, and at least one other glass substrate, the substrates being held together by a frame structure, said glazing providing a separation between an exterior space and a interior space, in which at least one intermediate gas layer is arranged between the two substrates.

Each substrate can be clear or colored. One of the substrates at least in particular can be made of glass colored in the mass. The choice of the type of coloring will depend on the level of light transmission and/or the colorimetric appearance sought for the glazing once its manufacture is complete.

A substrate of the glazing, in particular the carrier substrate of the stack, can be curved and/or tempered after the deposition of the stack. It is preferable in a multiple glazing configuration for the stack to be arranged so as to be turned towards the side of the spacer gas layer.

The glazing may also be triple glazing consisting of three sheets of glass separated two by two by a gas layer. In a triple glazing structure, the carrier substrate of the stack can be on face 2 and/or face 5, when it is considered that the incident direction of the sunlight passes through the faces in increasing order of their number. .

The present invention also relates to the material for implementing the process for obtaining, or manufacturing, according to the invention, that is to say the material of step a), before step b ) treatment.

The details and advantageous characteristics of the invention emerge from the following non-limiting examples, illustrated using the attached figures illustrating:

- [fig. 1] illustrates a structure of a functional monolayer stack according to the invention, the functional layer being deposited directly on a blocking underlayer and directly under a blocking overlayer, the stack being illustrated during the treatment using a source producing radiation;

- [fig. 2] illustrates double glazing incorporating a stack according to the invention;

- [fig. 3] illustrates the resistance per square, in ohms per square, of some examples of stacks of thin layers as a function of the running speed S of the substrate in meters per minute during the treatment illustrated in FIG. 1;

- [fig. 4] illustrates the light absorption LA, in percent, of certain examples of stacks of thin layers as a function of the running speed S of the substrate in meters per minute during the treatment illustrated in FIG. 1; and

- [fig. 5] illustrates the light absorption LA, in percent, of certain examples of stacks of thin layers as a function of the running speed S of the substrate in meters per minute during the treatment illustrated in FIG. 1 and as a function of the thickness of the last layer of the stack and the pressure inside the deposition chamber of this layer.

In FIGS. 1 and 2, the proportions between the thicknesses of the various layers or of the various elements are not strictly observed in order to facilitate their reading.

FIG. 1 illustrates a structure of a functional single-layer stack 14 according to the invention deposited on a face 11 of a transparent glass substrate 10, in which the single functional layer 140, in particular based on silver or an alloy metal containing silver, is disposed between two antireflection coatings, the underlying antireflection coating 120 located below the functional layer 140 in the direction of the substrate 30 and the overlying antireflection coating 160 disposed above the functional layer 140 opposite the substrate 30. These two antireflection coatings 120, 160 each comprise at least one dielectric layer 122, 128; 162, 164, 166, 169.

In FIG. 1, the functional layer 140 is located indirectly on the underlying anti-reflective coating 120 and indirectly under the overlying anti-reflective coating 160: there is an under-blocking layer 130 located between the underlying anti-reflective coating 120 and the functional layer 140 and an overblocking layer 150 located between the functional layer 140 and the antireflection coating 160.

Such a stack of thin layers can be used in a multiple glazing 100 creating a separation between an exterior space ES and an interior space IS; this glazing may have a double glazing structure, such as illustrated in FIG. 2: this glazing then consists of two substrates 10, 30 which are held together by a frame structure 90 and which are separated from each other by an intermediate layer of gas 15.

In figure 2, the incident direction of the sunlight entering the building is illustrated by the double arrow, on the left.

However, it can also be envisaged that in this double glazing structure, one of the substrates has a laminated structure.

A first series of examples was produced on the basis of the stacking structure 14 illustrated in FIG. 1 with, starting from the surface 11 of the substrate 10, with a thickness of 4 mm, only the following layers, in this order:

- a dielectric layer of titanium dioxide, TiC 122 with a physical thickness of 24 nm, deposited from a titanium target in an atmosphere of 6.25% oxygen on the total of argon and oxygen and under a pressure of 2×10′ ³ mbar;

- a zinc-based oxide layer, ZnO 128, with a physical thickness of 4 nm, deposited from a ZnO ceramic metal target, in an argon atmosphere and under a pressure of 2.10' ³ mbar ;

- a metallic functional layer 140 based on silver, and more precisely here on silver, with a physical thickness of 13.5 nm, deposited from a silver metallic target, in an argon atmosphere and under a pressure of 8.10 ³ mbar;

- an overblocking layer 150, metallic, in titanium, with a physical thickness of 0.7 nm, deposited from a titanium target, in an argon atmosphere and under a pressure of 8× ^{10 −3} mbar;

- a dielectric layer of zinc-based oxide, ZnO 162, with a physical thickness of 4.0 nm, deposited from a ZnO ceramic target, in an argon atmosphere and under a pressure of 2.10' ³ mbar;

- a dielectric layer of titanium dioxide, TiOz 164 with a physical thickness of 12 nm, deposited from a titanium target in an atmosphere of 6.25% oxygen on the total of argon and oxygen and under a pressure of 2.10 ³ mbar;

- a silicon-based nitride dielectric layer, SisN/i, 166 with a physical thickness of 25 nm, deposited from a silicon target doped with aluminum, 92% by weight silicon and 8% by weight aluminum in an atmosphere of 45% nitrogen on the total of nitrogen and argon and under a pressure of ^2.10'3 mbar;

- a metallic layer 168, absorbent, in Sn _x Zn _y , with a physical thickness of 2 nm, deposited from a metallic target containing 50% by weight of tin and 50% by weight of zinc in an atmosphere of 'argon and under a pressure of 2.10' ³ mbar.

The Sn and Zn elements each have a ratio 0<n/k<5 over the entire visible wavelength range and an electrical resistivity in the bulk state which is greater than 10' ⁵ Ω.cm.

Silver also has a ratio of 0<n/k<5 over the entire visible wavelength range, but its electrical resistivity in the bulk state is less than 10' ⁵ Q.cm.

In this first series, the stack described in the preceding paragraph constitutes a reference (“Ref >> in the figures); this reference is based on examples 2 and 3 of international patent application No. WO 2016/051069.

In this first series, an example 1 ("Ex. 1 >> in the figures) was produced further comprising a dielectric overlayer 169, in ZrC, with a thickness of 10 nm, which is located on and in contact with the metallic absorbent layer 168 and which is deposited from a zirconium metallic target, in an atmosphere containing 28.5% oxygen on the total of argon and oxygen and under a pressure of 2× ^{10 −3} mbar.

FIG. 3 illustrates along the ordinate the resistance per square, Rsq, in ohms per square of the reference stack and of example 1 thus deposited, this resistance per square being measured after a laser treatment.

This laser treatment consisted here of a scrolling of the substrate 10 coated with the stack 14 on one side at a speed S varying from 7 meters per minute to 13 meters per minute under a laser line 20 with a continuous beam of a length wavelength of 973.1 nm, 0.06 mm wide, 11.20 mm long and total power of 453 W, with the laser line directed almost perpendicular to the face 11 (with an inclination of 7°) and in the direction of the stack 14, that is to say by arranging the laser line above the stack, as visible in FIG. 1 (the arrow straight black illustrating the orientation of the emitted light), at a distance of 114 mm from the face 11 .

This curve shows that there is an interest in using a dielectric overlayer 169 of zirconium oxide, ZrCh, because the square resistance of the stack tends to be lower in the usual speed range, from 7 to 12 m. /minute.

Such a situation makes it possible in a first approach to increase the solar factor at constant functional layer thickness, or even in a second approach to reduce the thickness of the functional layer to increase the solar factor even more without modifying the square resistance previously obtained. .

FIG. 4 illustrates the ordinate of the light absorption, LA, in percent, of the reference stack and of Example 1 thus deposited. Before the laser treatment, the LA light absorption of the reference was 24.5% and that of Example 1 was 23.0%. The laser treatment caused the decrease in light absorption LA and this decrease is greater for example 1 than for the reference, whatever the scrolling speed. It is therefore possible to increase the running speed of the substrate, and thus increase productivity.

A second series of three examples was produced on the basis of the structure of the reference stack with, in addition, a dielectric overlayer 169, in ZrC, which is located on and in contact with the metallic absorbing layer 168:

- for example 2 ("Ex. 2" in the figures) with a thickness of 10 nm, and deposited from a metallic zirconium target, in an atmosphere of 28.5% oxygen on the total of argon and oxygen and under a pressure of 5.10 ³ mbar;

- for example 3 with a thickness of 2 nm, and deposited from a metallic zirconium target, in an atmosphere containing 28.5% oxygen on the total of argon and oxygen and under a pressure of 2.10' ³ mbar;

- for example 4 with a thickness of 2 nm, and deposited from a target metallic zirconium, in an atmosphere of 28.5% oxygen on the total of argon and oxygen and under a pressure of ^5.10'3 mbar.

All these examples have been the subject of the same laser treatment as before,

Figure 5 illustrates the light absorption LA of the reference and examples 1 and 2, measured as before. The light absorption of example 2 is similar to that of example 1, even slightly lower for higher substrate running speeds. The resistance per square of example 2 is otherwise identical to that of example 1 at the same frame rate.

The scratch resistance was tested with a "Scratch Hardness Test 413" test machine from the company ERICHSEN: a Van Laar hard metal tip with a diameter of 0.55 mm equipped with a tungsten carbide tip is moved and loaded with a weight on the substrate at a given speed. The visibility through the area tested by the tip is noted as a function of the load.

It was found on the one hand that for high loads, of 3 Newtons and 5 Newtons, examples 1 to 4 all show a less visible scratch than the reference and on the other hand that examples 1 and 2 show a scratch less visible than that of examples 3 and 4.

A third series of examples was carried out to test the following layers, deposited as before, at the end of the same stack:

Table 1

For Example 5, the same metal target, 50% by weight of tin and 50% by weight of zinc, was used for the two layers terminating the stack, but the dielectric overlayer 169 was deposited not in an atmosphere of pure argon as for the absorbent metal layer 168, but in an atmosphere of 14 argon and % oxygen. For example 6, the dielectric overlayer 169 was deposited from a TiCh ceramic target, in an argon atmosphere containing approximately 6% oxygen.

For example 7, the dielectric overlayer 169 was deposited from a silicon target at 92% by weight silicon and 8% by weight aluminum, in an argon atmosphere containing approximately half of argon and half oxygen.

For Example 8, which is a counter-example without an absorbent metal layer 168, the dielectric overlayer 169 was deposited in an atmosphere of ¼ argon and % oxygen.

For example 9, which is a counter-example with a dielectric overlayer 169 which does not comprise any oxide, the dielectric overlayer 169 was deposited from a silicon target with 92% by weight of silicon and 8% by weight of aluminum in an atmosphere of 45% nitrogen on the total of nitrogen and argon.

The resistance per square, Rsq, in ohms per square of the stacks as well as the light absorption LA, in percent, were measured as before, after identical laser treatment, at different speeds S and these data are summarized in Table 2 below.

Table 2

For all these examples, the low speed value generates the low value of the square resistance range and the low value of the light absorption range; the high speed value generates the high value of the square resistance range and the high value of the light absorption range; the resistance per square increasing substantially constantly over the indicated range as a function of speed and the light absorption increasing substantially constantly over the entire indicated range as a function of speed. These examples 5 to 7 also show the advantage of using an oxide dielectric overlayer 169 because the square resistance of the stack tends to be lower in the usual speed range, from 7 to 12 m/minute and the Light absorption also tends to be lower. For example 8, without an absorbent metal layer 168, the treatment with the source producing the radiation does not produce a sufficient effect on the sheet resistance of the stack: the sheet resistance of 2.5 ohms per square is reached from a speed of 5 meters per minute, which is too slow. For example 9, with dielectric overlayer 169 not comprising oxygen, the light absorption remains much too high, whatever the speed, meaning that the oxidation effect on the absorbing metal layer 168 during the treatment at using the source producing the radiation is not achieved.

The present invention is described in the foregoing by way of example. It is understood that the person skilled in the art is able to make different variants of the invention without departing from the scope of the patent as defined by the claims.

Claims

1. Method for obtaining a material comprising a substrate (10), glass, coated on one side (11) with a stack of thin layers (14) with reflection properties in the infrared and / or in the radiation sunglasses comprising at least one, or even just one, metallic functional layer (140), in particular based on silver or on a metallic alloy containing silver, and two antireflection coatings (120, 160), the said antireflection coatings each comprising at at least one dielectric layer (128, 162), said functional layer (140) being placed between the two antireflection coatings (120, 160), said method comprising: a)- depositing on one face (11) of said glass substrate (10) , of a stack of thin layers (14) with reflection properties in the infrared and/or in solar radiation comprising at least one, or even just one, metallic functional layer (140), in particular based on silver or metal alloy containing silver and at least two coatings antireflection coatings (120, 160), said antireflection coatings each comprising at least one dielectric layer (128, 162), said functional layer (140) being placed between the two antireflection coatings (120, 160), then b) - the treatment of said stack of thin layers (14) using a source producing radiation and in particular infrared radiation, characterized in that said stack deposited in step a), opposite said substrate (30), ends , starting from the substrate, by:

- an absorbent metal layer (168), with a physical thickness of said absorbent metal layer (168) which is between 1.0 and 8.0 nm, or even between 1.5 and 5.0 nm, or even between 1.8 and 2.5 nm; then

- a dielectric overlayer (169) comprising oxygen, which is located on and in contact with said absorbent metal layer (168) with a physical thickness of said dielectric overlayer (169) which is between 1.5 and 40.0 nm , or even between 2.6 and 35.0 nm, or even between 5.6 and 30.0 nm.

2. Method according to claim 1, wherein in step b) said treatment is carried out in an atmosphere not comprising oxygen.

3. A method according to claim 1 or 2, wherein said metallic functional layer (140) has a physical thickness which is between 7.2 and 22.0 nm, or even between 9.0 and 16.0 nm, or even between 10.6 and 14.4 nm.

4. Method according to any one of claims 1 to 3, in which said dielectric overlayer (169) comprising oxygen has a physical thickness which is between 5.6 and 25.0 nm, or even between 6.6 and 20, 0 nm, or even between 7.6 and 15.0 nm.

5. Method according to any one of claims 1 to 4, wherein said absorbent metal layer (168) comprises at least one element chosen from Sn, Zn, Ti, In, Nb.

6. Method according to any one of claims 1 to 5, wherein said dielectric overlayer (169) comprises at least one element chosen from Sn, Zn, Ti, Si, Zr.

7. Method according to any one of claims 1 to 6, wherein said dielectric overlayer (169) consists of oxide of one or more elements.

8. Method according to any one of claims 1 to 7, wherein said antireflection coating (120) located under said metallic functional layer (140) and/or said antireflection coating (160) located above said metallic functional layer (140) has a dielectric layer comprising nitrogen, preferably a silicon nitride dielectric layer.

9. Material for carrying out the method according to any one of claims 1 to 8.

10. Multiple glazing comprising a material obtained by implementing the method according to any one of claims 1 to 8, and at least one other glass substrate (30), the substrates (10, 30) being held together by a frame structure (90), said glazing providing a separation between an exterior space (ES) and an interior space (IS), in which at least one spacer layer of gas (15) is arranged between the two substrates.