DE102013108218B4 - Process for the production of a transparent IR-reflecting layer system - Google Patents

Abstract

Method for the production of an IR-reflective layer system by means of sputtering, in that on a substrate (S0) the layers of an IR-reflective layer system with a base layer arrangement (GA), comprising at least one base layer, with at least one functional layer arrangement (FA, FA1, FA2), at least one silver-containing functional layer (F) and a seed layer lying under the functional layer, and comprising a cover layer arrangement (DA), comprising at least one cover layer (D1, D2), are deposited, characterized in that the seed layer with a lower seed sublayer containing titanium dioxide (K1) and with an upper partial seed layer containing zinc oxide (K2) is deposited, that the deposition of the lower partial seed layer (K1) from a ceramic, substoichiometric titanium oxide target takes place reactively under an oxygen-containing sputtering atmosphere and that the oxygen content of the total amount of gas in the sputtering atmosphere in the area h is from 1% to 20%.

Description

The invention relates to a method for producing a transparent infrared radiation (IR) reflective layer system which is arranged on a transparent substrate.

Transparent IR-reflecting layer systems, which also include the partially transparent layer systems and which are referred to below as IR-reflecting layer systems, are known as so-called LowE layer systems in thermal insulation glazing. They should prevent the radiation of heat, i.e. have a low energy emission. According to Kirchhoff's law of radiation, this is synonymous with low absorption and high reflection in the infrared radiation (IR) wavelength range of >> 3 µm. According to different applications, either high transmission or a targeted adjustable transmission in the range of global solar radiation (solar energy transmission) is desired, which covers the wavelength ranges of near infrared (NIR) and visible light (VIS) from 300 nm to <3pm (solar energy). Area). The ratio of transmission, limited to the visible light range, relative to energy transmission characterizes the filter effect for visible light and is referred to as selectivity. In building glazing, in climatic regions with predominant energy loss, a high solar energy transmission of the glazing is preferred, which results in a solar energy gain, while in climatic regions in which the energy input through the glazing predominates, a low energy transmission and, associated with this, a high selectivity of the glazing used is beneficial.

In the first case of the versions of the LowE layer system required in thermal insulation glazing, a steep edge in the transition from NIR to IR of the light is desired, which represents a strong decrease in transmission and a strong increase in reflection, with the reflection-transmission edge regularly increasing with the number of functional IR reflective layers becomes steeper. In the second case, which is also referred to as sun protection glazing (LowE-Sun), the transmission is reduced in the entire solar area and / or a color shade of the layer system can be set in a targeted manner. Furthermore, the above-described edge of the decrease in transmission is preferably shifted in the direction of the transition from the visible (VIS) to the near-infrared (NIR) spectral range, which lies at approx. 800 nm.

In general, an IR-reflecting layer system, viewed from the substrate upwards, initially comprises a base layer arrangement, which is used in particular for the adhesion of the system to the glass, the chemical and / or mechanical resistance and / or the adjustment of the optical properties of the system, e.g. the anti-reflective coating.

A functional layer arrangement follows over the base layer arrangement, which comprises the IR reflective layer and, optionally, further layers which support this function and can enable its optical, chemical, mechanical and electrical properties to be influenced. The IR reflective layers consist of a noble metal, usually silver, or a noble metal alloy. Other materials are also used, mostly layers comprising metallic or dielectric nickel or chromium or alloys of both. These materials in turn require an adaptation of the other layers belonging to the layer system. The optional additional layers of the functional layer arrangement include, in particular, blocker layers that prevent or at least significantly reduce diffusion and migration processes in the functional layer and are arranged above and / or below an IR reflective layer, as well as absorbing layers through which the light transmission of the layer system can be adjusted leaves.

An IR-reflecting layer system is closed at the top by a cover layer arrangement which comprises at least one mechanically and / or chemically stabilizing protective layer. The cover layer arrangement usually consists of one or more layers of a dielectric oxide or nitride or oxynitride of a metal and / or a metal mixture and / or a semiconductor. These dielectric materials are considered absorption-free materials, which qualifies them for the described optical function.

As described, the term “layer arrangement” generally includes more than one layer, but also includes the fact that a layer arrangement only consists of a single layer that realizes the respective function. The assignment of individual layers to the basic, functional, top or further layer arrangement is not to be carried out clearly in every case, since each layer has an influence on the neighboring layers as well as on the entire system. In general, a layer is assigned based on its function.

For example, those layers are generally assigned to a base layer arrangement which primarily represent a mediator between the substrate and the further layer sequence. Further layers of the base layer arrangement can also influence the properties of the layer system as a whole, such as anti-reflective layers or protective layers.

In addition to the IR reflective layer, the functional layer arrangement also includes layers that directly influence its properties, such as blocker layers to suppress diffusion processes of adjacent layers into the IR reflective layer or such as mediator layers that serve to adhere or adjust electrical and optical settings of the adjacent layer.

Layers of the top layer arrangement close off the layer system at the top and, like the base layer arrangement, can functionally affect the entire system.

A so-called single-low-E constructed in this way can be supplemented by inserting one (double-low-E) or several further functional layer arrangements which are constructed by coupling or middle layer arrangements on the first functional layer arrangement. The above considerations must also be used as a basis for the assignment of a layer to the middle layer arrangement. The respective sequence of individual layers and layer arrangements can be modified either within a layer arrangement or in the sequence of layer arrangements in such a way that special requirements arising from the application or the manufacturing process can be met.

Thus, in the course of the production of the layer system, different temperature loads occur in already applied layer sequences, which are caused by an energy input associated with the deposition or by different treatment steps of deposited layers. As the relevant state of the art, the WO 2014/028283 A2 and the US 2008/0220261 A1 to watch.

In addition, IR-reflecting layer systems for hardening and / or reshaping the substrate are often subjected to annealing processes. In this case, they have such a layer sequence with layer properties that allow a substrate carrying the layer system to be subjected to a heat treatment and changes in the optical, mechanical and chemical properties of the layer system that occur within defined limits. Depending on the application of a coated substrate, its layer system is exposed to different climatic conditions in the tempering process in different time regimes.

Due to such temperature loads, there are various processes that change the reflectivity of the IR reflective layer and the transmission of the layer system, in particular the diffusion of components of other layers into the IR reflective layer and vice versa and, as a result, oxidation processes in the IR reflective layer.

To avoid such diffusion and oxidation processes, a blocker layer is inserted on one or both sides of the IR reflective layer, which serves as a buffer for the diffusing components. These blocker layers are structured and arranged according to the temperature load that occurs and protect the sensitive, often very thin, IR reflective layer or the IR reflective layers from the influence of neighboring layers. By inserting one or more blocker layers, in particular color shifts in the layer system and the increase in the sheet resistance of the layer system as a result of the tempering process are reduced.

In particular, NiCr or NiCrOx layers, which enclose the IR-reflecting silver layers or protect them at least on one side, are known as blocking layers of temperable layer systems. However, the blocker layers lead to a reduction in the conductivity of the silver layer and thus to a reduction in the IR reflection. If a silver layer with a sheet resistance of approx. 5 Ohm / Sq. deposited and embedded in two NiCrOx layers, this embedding can increase the sheet resistance by approx. 1.5 Ohm / Sq. lead to 6.5 Ohm / Sq. A reduction in the sheet resistance with the same thickness of the functional layer is achieved by depositing a seed layer directly below the functional layer. Zinc oxide is used as a seed layer for common IR-reflecting layer systems. So is from the US 2006/0 159 932 A1 a Low-E coating is known in which at least one zinc oxide-containing layer is arranged adjacent to the IR-reflecting layer.

Titanium oxide, which is used as an anti-reflective layer, can also serve as a seed layer at the same time ( US 2008/0220261 A1 ). However, the reduction in sheet resistance reaches a limit from a thickness of approx. 8 nm.

In addition, it was found that the reflection and transmission properties of the layer system are also influenced by diffusion processes emanating from the glass. In order to influence this, a barrier layer is often inserted below the functional layer arrangement, which is intended to reduce the diffusion of sodium ions of the glass into the layer system. With such a barrier layer, quality problems can also be reduced which can be traced back to undefined initial states in the raw glass, ie fluctuating chemical composition of the glass, in particular with regard to its sodium content. In addition, cause others Influences on glass, such as corrosion or marks from the suction cups used to handle the glass, which often cannot be determined by visual checks and cannot be removed by conventional cleaning, undesirable changes in the properties of the layer system. A particular disadvantage of such glass influences is that their effects on the properties of the layer system only become visible after the tempering process.

The different optically effective layer systems are often deposited by means of sputtering, which enables the production of suitable individual layers, even with only very small layer thicknesses, whose composition and properties can, as is known, be set very well and reproducibly by means of the target materials, the type of sputtering and the sputtering parameters.

For example, the US 2003/0 049 464 A1 an IR-reflecting layer system produced by means of sputtering, in which a zinc oxide layer is arranged on a base layer-supported TiO _x (1≤x≤2) below the functional layer. Optically effective, in particular IR-reflecting layer systems are often subjected to various heat treatments, for example tempering processes for hardening and / or deforming the coated substrate. In this case, they have such a layer sequence with layer properties that allow changes in the optical, mechanical and chemical properties of the layer system that occur during a heat treatment to be kept within defined, narrow limits. Depending on the application of a coated substrate, its layer system is exposed to different climatic conditions in the tempering process in different time regimes.

It is the object of the invention to provide a method for producing such an IR-reflective layer system which increases the IR reflection of the known layer systems and thus reduces their emissivity, while maintaining the tempering ability achievable with the layer system, in particular with regard to transmission and color stability.

A method according to claim 1 is proposed to achieve the object. The dependent claims describe advantageous configurations.

It was found that with the two-part seed layer according to the invention and titanium dioxide as an essential component of its lower seed sub-layer, a further reduction in the sheet resistance of the functional layer beyond the previous limit can be achieved.

The lower partial seed layer is deposited according to the invention by means of reactive sputtering with a flow of oxygen to the working gas from a ceramic, substoichiometric titanium oxide. The proportion of oxygen in the total amount of gas in the sputtering atmosphere is in the range from 1% to 20%, in a preferred embodiment in the range from 1% to 10%.

In the description, a layer containing titanium dioxide or another material should be understood to be such a material composition that the essential component determining the electro-optical characteristics is the named material. This includes the fact that it may contain technologically-related impurities or technologically-related admixtures that are useful for process control during deposition or, e.g. during cathode sputtering, for target production. Such impurities or technological admixtures are mostly in the range of less than 1%, but can also amount to a few percent.

It was possible to reduce the sheet resistance of the functional layer by adding the titanium dioxide layer by up to 10%. The modification of the layer system can also be applied to layer systems to be tempered. An increased effect was even observed here. For example, tempered layer systems according to the invention have a sheet resistance which is up to 20% lower than that of a conventional layer system. The comparison of the achievable values of the sheet resistance refers to functional layers of the same material and the same thickness due to the thickness dependency of the sheet resistance.

With the seed layer according to the invention, the known IR-reflecting layer systems can be modified without a relevant change in the other optical performance indicators of the layer system. Good emissivity values were achieved for IR-reflecting layer systems which, according to an embodiment of the invention, comprise a functional layer with silver and an upper partial seed layer with zinc oxide.

As described above, in a further embodiment of the invention the seed layer can be omitted, for example in a low-e-sun layer system, if the functional layer arrangement also has a blocker layer under the functional layer.

A seed layer is regularly deposited under the IR-reflecting functional layer in order to positively influence the reflective properties of the functional layer and its adhesion. The seed layer is in the sense of a layer A seed layer is inserted, which influences the layer structure of the functional layer during the deposition in such a way that the desired, low sheet resistance is achieved. The optimal layer thickness is determined through tests or simulations. The optimal layer thicknesses can also be determined for the partial layers of the seed layer according to the invention, depending on the materials used in the layer system, by experiments or simulations. To solve the problem, layer thicknesses of the lower partial seed layer have been found to be significantly below those of the dielectric layers in the base layer arrangement. According to one embodiment of the invention, in particular for layer systems with a silver functional layer and zinc oxide partial seed layer, they are in the range from 1 nm to 18 nm, preferably d = 1-15 nm, as advantageous.

According to a further embodiment, the seed layer according to the invention makes it possible to protect the functional layer from undesired deterioration with only one blocker layer arranged above the functional layer. Optionally, the layer system can be protected against influences from the substrate in the known manner by a barrier layer formed in the base layer arrangement.

The seed layer according to the invention also leads to a reduction in emissivity in the case of IR-reflecting layer systems with more than one functional layer arrangement. For this purpose, at least one of the functional layer arrangements, for example the lower one, has the partial seed layer made of titanium dioxide. Alternatively, further or all functional layer arrangements can be designed in this way.

To protect the IR-reflecting layer system from atmospheric influences or deterioration during its use, the cover layer arrangement can comprise a silicon-based protective layer which is formed as a mixed layer of a sequence of silicon oxynitride and silicon nitride above it. Such a protective layer also brings about, in particular, a significant improvement in the mechanical resistance of the layer system and in the scratch resistance and the adhesion of the cover layer arrangement. In this case, the mixed layer can be designed both as a gradient layer and as consisting of sub-layers, the sub-layers, for example, directly adjoining one another. Such a cover layer arrangement can furthermore be supplemented by at least one metal oxide or metal mixed oxide layer located below the silicon oxynitride, for example containing zinc stannate or tin oxide.

It also proves to be advantageous if an IR-reflective according to the invention can be supplemented by an uppermost layer which closes off the layer system at the top and which, according to an embodiment, consists of titanium dioxide and can further improve the abrasion resistance of the system. In addition, titanium dioxide, like silicon nitride as the uppermost area of the protective layer, is highly refractive, so that its optical effect can be adjusted to a negligible extent depending on its layer thickness.

To produce an optically effective layer system, the layers of the base layer arrangement and the functional layer arrangement or the functional layer arrangements with an intermediate layer arrangement are deposited one after the other by means of sputtering, for example by means of magnetron sputtering, on a substrate.

• 1 ein IR-reflektierendes Schichtsystem mit einer Funktionsschicht und einer erfindungsgemäßen Keimschicht
• 2 IR-reflektierendes Schichtsystem gemäß 1 mit einer alternative Ausgestaltung der Deckschichtanordnung und
• 3 ein IR-reflektierendes Schichtsystem mit zwei Funktionsschichten und einer erfindungsgemäßen Schutzschicht.

The invention will be explained in more detail below on the basis of exemplary embodiments. The accompanying drawing shows in

• 1 an IR-reflecting layer system with a functional layer and a seed layer according to the invention
• 2 IR-reflecting layer system according to 1 with an alternative embodiment of the cover layer arrangement and
• 3 an IR-reflecting layer system with two functional layers and a protective layer according to the invention.

1 As an IR-reflecting layer system, it represents a single-low-E layer system in which the one functional layer arrangement is directly below FA of the layer system that consists of two partial seed layers K1 , K2 existing seed layer is arranged.

1. a) Grundschichtanordnung GA mit Si3N4, 15-30 nm, als einzige Grundschicht, alternativ auch SiOxNy, oder zwei Grundschichten übereinander;
2. b) eine Funktionsschichtanordnung FA aus
   • - Ti02, 1-15 nm, als untere Keimteilschicht K1 der Keimschicht,
   • - ZnO, 7-10 nm, als obere Keimteilschicht K2 der Keimschicht,
   • - Ag, 12-15 nm, als Funktionsschicht F und
   • - eine Blockerschicht B aus einer Nickel und Chrom enthaltenden Verbindung oder einem unterstöchiometrischen Oxid, Nitrid oder Oxinitrid davon, im Ausführungsbeispiel: NiCrOx, 0,5-3 nm;
3. c) eine Deckschichtanordnung DA aus
   • - SnO2, 15-20 nm, als erste Deckschicht D1, und
   • - Si3N4, 20-45 nm, als zweite Deckschicht D2.

On a washed substrate S0 From 4 mm float glass, the following layers are applied by magnetron sputtering to produce the single-low-E layer system:

1. a) Base layer arrangement GA with Si3N4, 15-30 nm, as the only base layer, alternatively also SiOxNy, or two base layers on top of each other;
2. b) a functional layer arrangement FA out
   • - Ti02, 1-15 nm, as the lower partial seed layer K1 the germ layer,
   • - ZnO, 7-10 nm, as the upper partial seed layer K2 the germ layer,
   • - Ag, 12-15 nm, as a functional layer F. and
   • - a blocker layer B. from a compound containing nickel and chromium or a substoichiometric oxide, nitride or oxynitride thereof, in the exemplary embodiment: NiCrOx, 0.5-3 nm;
3. c) a cover layer arrangement THERE out
   • - SnO2, 15-20 nm, as the first top layer D1 , and
   • - Si3N4, 20-45 nm, as a second top layer D2 .

With such a structure of the functional layer arrangement, a sheet resistance of the deposited silver layer of 4.3 ohms / sqr was achieved, for example, with a 13 nm thick TiO2 layer. After tempering, the value decreased to 2.8 Ohm / sqr, which is a reduction of approx. 10% or 24% after tempering compared to the layer systems without partial seed layer T1 corresponds to.

Alternatively, the cover layer arrangement THERE as the lowest layer and thus directly adjacent to the functional layer arrangement FA instead of SnO2 have a first layer of zinc stannate or other of the known cover layer arrangements.

The top layer arrangement THERE The embodiment variants described above can further comprise a third cover layer as the top layer of the layer system, which consists of TiO2 with a thickness in the range 1-6 nm.

• - SnO2, 15-20 nm, als untere Deckschicht D1,
• - SiOxNy, 5-15 nm, als erste Teilschutzschicht T1, mit 0,1-25 % 02 im Reaktivgas und
• - Si3N4, 10-45 nm, als zweite Teilschutzschicht T2 und
• - Ti02, 1-6 nm, als optionale dritte Teilschicht T3.

The embodiment according to 2 differs from the one previously described by the structure of the cover layer arrangement THERE . This consists of a protective layer arrangement SA, which consists of three partial protective layers T1 , T2 , T3 exists, as well as an underlying lower cover layer D1 made of titanium dioxide.

• - SnO2, 15-20 nm, as the lower cover layer D1 ,
• - SiOxNy, 5-15 nm, as the first partial protective layer T1 , with 0.1-25% 02 in the reactive gas and
• - Si3N4, 10-45 nm, as a second partial protective layer T2 and
• - Ti02, 1-6 nm, as an optional third sub-layer T3 .

For the structure of the basic and functional layer arrangements, refer to the explanations 1 refer.

• d) Grundschichtanordnung GA mit Si3N4, 15-30 nm, als einzige Grundschicht, alternativ auch SiOxNy, oder zwei Grundschichten übereinander;
• e) erste Funktionsschichtanordnung FA1 aus
  • - Ti02, 1-15 nm, als untere Keimteilschicht K1,
  • - ZnO, 7-10 nm, als obere Keimteilschicht K2,
  • - Ag, 12-15 nm, als Funktionsschicht F und
  • - eine Blockerschicht B aus einer Nickel und Chrom enthaltenden Verbindung oder einem unterstöchiometrischen Oxid, Nitrid oder Oxinitrid davon, im Ausführungsbeispiel: NiCrOx, 0,5-3 nm;
• a) ZnSnO3, alternativ SnO2, 40-90 nm, als einzige Zwischenschicht der Zwischenschichtanordnung ZA;
• b) zweite Funktionsschichtanordnung FA2,
• f) erste Funktionsschichtanordnung FA1 aus
  • - ZnO, 7-10 nm, als einteilige Keimschicht K,
  • - Ag, 12-15 nm, als Funktionsschicht F und
  • - eine Blockerschicht B aus einer Nickel und Chrom enthaltenden Verbindung oder einem unterstöchiometrischen Oxid, Nitrid oder Oxinitrid davon, im Ausführungsbeispiel: NiCrOx, 0,5-3 nm;
• g) eine Deckschichtanordnung DA aus
  • - SnO2, alternativ ZnSnO3, 15-20 nm, als erste Deckschicht D1, und
  • - Si3N4, 20-45 nm, als zweite Deckschicht D2.

The shift system according to 3 differs from that after 1 by a further one, between the functional layer arrangement and the base layer arrangement GA according to 1 inserted functional layer arrangement. In order from the substrate S0 upwards are the lower functional layer for differentiation FA1 and the one above it with FA2 designated. In the exemplary embodiment shown, only the lower of the two functional layer arrangements has FA1 , FA2 the two-part seed layer according to the invention. The upper functional layer arrangement comprises a one-piece seed layer K made of ZnO. Both functional layer arrangements FA1 and FA2 are through an interlayer arrangement ZA separated from each other. This results in the following IR-reflecting layer system:

• d) base layer arrangement GA with Si3N4, 15-30 nm, as the only base layer, alternatively also SiOxNy, or two base layers on top of each other;
• e) first functional layer arrangement FA1 out
  • - Ti02, 1-15 nm, as the lower partial seed layer K1 ,
  • - ZnO, 7-10 nm, as the upper partial seed layer K2 ,
  • - Ag, 12-15 nm, as a functional layer F. and
  • - a blocker layer B. from a compound containing nickel and chromium or a substoichiometric oxide, nitride or oxynitride thereof, in the exemplary embodiment: NiCrOx, 0.5-3 nm;
• a) ZnSnO3, alternatively SnO2, 40-90 nm, as the only interlayer of the interlayer arrangement ZA ;
• b) second functional layer arrangement FA2 ,
• f) first functional layer arrangement FA1 out
  • - ZnO, 7-10 nm, as a one-piece seed layer K ,
  • - Ag, 12-15 nm, as a functional layer F. and
  • - a blocker layer B. of a compound containing nickel and chromium or a substoichiometric oxide, nitride or oxynitride thereof, in the exemplary embodiment: NiCrOx, 0.5-3 nm;
• g) a cover layer arrangement THERE out
  • - SnO2, alternatively ZnSnO3, 15-20 nm, as the first top layer D1 , and
  • - Si3N4, 20-45 nm, as a second top layer D2 .

Also the double-low-E layer system of the 3 can in addition to the functional layer arrangement according to the invention FA one or more of the too 1 or 2 have described layers or layer arrangements. Also the interlayer arrangement ZA can consist of more than one layer.

List of reference symbols

S0

Substrate

GA

Base layer arrangement

FA, FA1, FA2

Functional layer arrangement

ZA

Interlayer arrangement

S.

Protective layer

THERE

Top layer arrangement

K

one-piece seed layer

F.

Functional layer

B.

Blocker layer

K1, K2

Seed sublayer

T1, T2, T3

Partial protective layer

D1, D2

Top layer

Claims (6)

Method for the production of an IR-reflective layer system by means of sputtering, in that on a substrate (S0) the layers of an IR-reflective layer system with a base layer arrangement (GA), comprising at least one base layer, with at least one functional layer arrangement (FA, FA1, FA2), at least one silver-containing functional layer (F) and a seed layer lying under the functional layer, and comprising a cover layer arrangement (DA), comprising at least one cover layer (D1, D2), are deposited, characterized in that the seed layer with a lower seed sublayer containing titanium dioxide (K1) and with an upper partial seed layer containing zinc oxide (K2) is deposited, that the deposition of the lower partial seed layer (K1) from a ceramic, substoichiometric titanium oxide target takes place reactively under an oxygen-containing sputtering atmosphere and that the oxygen content of the total amount of gas in the sputtering atmosphere is in the area ch is from 1% to 20%. Procedure according to Claim 1 , the proportion of oxygen in the total amount of gas in the sputtering atmosphere being in the range from 1% to 10%. Method for producing an IR-reflecting layer system according to one of the preceding claims, characterized in that the lower partial seed layer (K1) is deposited with a layer thickness in the range of d = 1-18 nm, preferably d = 1-15 nm. Method for producing an IR-reflecting layer system according to one of the preceding claims, characterized in that only one blocker (B) is deposited in the functional layer arrangement (FA, FA1, FA2), which blocker is arranged above the functional layer (F). Method for producing an IR-reflecting layer system according to one of the preceding claims, characterized in that at least one further functional layer arrangement (FA1, FA2) is deposited between the cover layer arrangement (DA) and the functional layer arrangement (FA1, FA2), each functional layer arrangement (FA1, FA2) is connected to an adjacent functional layer arrangement (FA1, FA2) by an intermediate layer arrangement (ZA) with at least one intermediate layer. Process for the production of an IR-reflecting layer system according to Claim 5 , characterized in that two functional layer arrangements (FA1, FA2) are deposited each with a structure according to one of the preceding claims.

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