FR3114264A1 - MATERIAL COMPRISING A STACK WITH AN ABSORBENT METALLIC LAYER AND A DIELECTRIC OVERLAYER AND METHOD FOR DEPOSITING THIS MATERIAL - Google Patents

Abstract

The invention relates to a material comprising a substrate (30) coated on one side (29) with a stack of thin layers (14) comprising at least one metallic functional layer (140) and an antireflection coating (160) located above said functional layer (140) opposite said substrate (30) terminates in:- a metallic layer (168), with a physical thickness of said metallic layer (168) which is between 1.0 and 8.0 nm , even between 1.5 and 5.0 nm, even between 1.8 and 2.5 nm; then- a dielectric overlayer (169) which is located over and in contact with said absorbent metallic layer (168). Abstract Figure: Figure 1

Description

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

The invention relates to a material comprising a 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 metallic functional layer, in particular based on 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.

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.

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, 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: an absorbent metallic 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 material comprising 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 based on silver or on a metallic alloy containing silver and at least two antireflection coatings, the said antireflection coatings each comprising at least one dielectric layer, the said functional layer being arranged between the two anti-reflective coatings, said material being remarkable in that said stack, 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 metal 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 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 does not contain nitrogen in order to maximize the effect of oxidation on the absorbent metal layer during the treatment.

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 may for example be TiO ₂ , ZrO ₂ , SiO ₂ , ZnO, SnO ₂ .

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 TiO _x , ZrO _x , SiO _x , SnO _x , with x > 2.

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

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 zinc-based oxide, ZnO, sub-layer which is located under and in contact with said functional layer, with a physical thickness of said zinc-based oxide, ZnO, sub-layer 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 titanium-based oxide dielectric underlayer, TiO₂, which is located under and in contact with said ZnO zinc-based oxide sublayer, with a physical thickness of said titanium-based oxide sublayer, TiO₂, 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 dielectric layer of nitride based on silicon, Si ₃ N ₄ .

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 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 or nitrogen atom. .

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 designates 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 element non-reactive (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. Indeed, it is not desired that such a layer can react at this location, and in particular be oxidized, 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 Si ₃ N ₄ silicon-based nitride dielectric layer does not include zirconium.

Preferably, moreover, said Si ₃ N ₄ silicon-based nitride dielectric layer does not contain 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 spacer gas layer is placed 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 a process for obtaining, or manufacturing, a material comprising 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 based on silver or on a metallic alloy containing silver and two antireflection coatings, the said antireflection coatings each comprising at least one dielectric layer, said functional layer being disposed between the two antireflection coatings, said method comprising the following steps, in order:
- the deposition on one side of said substrate of 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 based on silver or metal alloy containing silver and at least two antireflection coatings, in order to form a material according to the invention, then
- the treatment of said stack of thin layers using a source producing radiation and in particular infrared radiation, in order to treat the stack of thin layers as such.

Said treatment is preferably carried out in an atmosphere not comprising oxygen.

The details and advantageous characteristics of the invention emerge from the following non-limiting examples, illustrated with the aid of the attached figures illustrating:
- 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;
- illustrates double glazing incorporating a stack according to the invention;
- illustrates the resistance per square, in ohms per square, of certain examples of stacks of thin layers as a function of the speed S of travel of the substrate in meters per minute during the treatment illustrated in ;
- 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 ; And
- 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 and as a function of the thickness of the last layer of the stack and of the pressure inside the chamber for depositing 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.

There illustrates a structure of a functional monolayer 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 on a metal alloy containing silver, is disposed between two anti-reflective coatings, the underlying anti-reflective coating 120 located below the functional layer 140 towards the substrate 30 and the overlying anti-reflective coating 160 disposed above the functional layer 140 at the opposite the substrate 30. These two antireflection coatings 120, 160 each comprise at least one dielectric layer 122, 128; 162, 164, 166, 169.

In , 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 anti-reflective 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, as illustrated in : 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 gas layer 15.

In , 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 has been produced on the basis of the stacking structure 14 illustrated in with, starting from surface 11 of substrate 10, 4 mm thick, only the following layers, in this order:
- a dielectric layer of titanium dioxide, TiO ₂ 122 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, TiO ₂ 164 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, Si ₃ N ₄ , 166 with a physical thickness of 25 nm, deposited from a silicon target doped with aluminum, at 92% by weight of silicon and 8 % by weight of aluminum in an atmosphere containing 45% nitrogen out of the total 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 of 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 bulk state electrical resistivity is less than 10 ^-5 Ω.cm.

In this first series, the stack described in the previous 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 ZrO ₂ , with a thickness of 10 nm, which is located on and in contact with the metal absorbent layer 168 and which is deposited from a metal target made of zirconium, in an atmosphere containing 28.5% oxygen on the total of argon and oxygen and under a pressure of 2.10 ^-3 mbar.

There 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 laser treatment.

This laser treatment consisted here of a scrolling of the substrate 10 at a speed S varying from 7 meters per minute to 13 meters per minute under a laser line 20 with a continuous beam with a wavelength of 973.1 nm, 0.06 mm wide, 11.20 mm long and with a total power of 453 W, with the laser line oriented almost perpendicular to the face 11 (with an inclination of 7°) and in the direction of the stack 14, i.e. by placing the laser line above the stack, as seen in (the right black arrow illustrating the orientation of the emitted light), at a distance of 114 mm from face 11.

This curve shows that there is an advantage in using an overlayer of zirconium oxide 169 because the resistance per square 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. .

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

Three other examples were made on the basis of the structure of the reference stack with, in addition, a dielectric overlayer 169, in ZrO ₂ , 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 containing 28.5% oxygen on the total 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 zirconium metal 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 metallic zirconium target, in an atmosphere containing 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,

There illustrates the light absorption LA of the reference and of Examples 1 and 2, measured as above. The light absorption of Example 2 is similar to that of Example 1, or 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 running speed.

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 and charged of 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.

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 (10)

Material comprising a glass substrate (10), coated on one side (11) with a stack of thin layers (14) with reflection properties in the infrared and/or in solar radiation comprising at least one, or even a single , metallic functional layer (140), in particular based on silver or on a metal alloy containing silver and at least two 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), characterized in that said stack, 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, even between 1.5 and 5.0 nm, even between 1.8 and 2.5 nm; Then
- a dielectric overlayer (169) comprising oxygen, which is located on and in contact with said absorbing 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. Material according to Claim 1, in which the said metallic functional layer (140) has a physical thickness which is between 7.2 and 22.0 nm, even between 9.0 and 16.0 nm, even between 10.6 and 14.4nm. Material according to Claim 1 or 2, in which the said dielectric overlayer (169) comprising oxygen has a physical thickness which is between 5.6 and 25.0 nm, even between 6.6 and 20.0 nm, even between 7.6 and 15.0 nm. Material according to any one of Claims 1 to 3, in which the said absorbent metallic layer (168) comprises at least one element chosen from among Sn, Zn, Ti, In, Nb. Material according to any one of Claims 1 to 4, in which the said dielectric overlayer (169) comprises at least one element chosen from among Sn, Zn, Ti, Si, Zr. Material according to any one of claims 1 to 5, wherein said dielectric overlayer (169) does not include nitrogen. Material according to any one of claims 1 to 6, 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) comprises a layer dielectric comprising nitrogen, preferably a silicon nitride dielectric layer. Multiple glazing comprising a material according to any one of claims 1 to 7, 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 intermediate gas layer (15) is arranged between the two substrates. Process for obtaining a material comprising a glass substrate (10), coated on one face (11) with 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, metal functional layer (140), in particular based on silver or on a metal alloy containing silver, and two antireflection coatings (120, 160), said antireflection coatings each comprising at least one dielectric layer (128, 162), said functional layer (140) being disposed between the two anti-reflective coatings (120, 160), said method comprising the following steps, in order:
- the deposition on one side (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 on a metallic alloy containing silver and at least two antireflection coatings (120, 160), in order to form a material according to any one of claims 1 to 7, then
- the treatment of said stack of thin layers (14) using a source producing radiation and in particular infrared radiation. A method according to claim 9, wherein said treatment is carried out in an atmosphere not comprising oxygen.