JP2013133260A - Low radiation laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low radiation laminate having excellent durability in a high humidity environment.SOLUTION: In the low radiation laminate, a low radiation laminated film is formed on a substrate. The low radiation laminated film has a zinc oxide layer a on the substrate, an Ag layer on the zinc oxide layer a, and a barrier layer on the Ag layer, and has a tin oxide layer as the uppermost layer of the low radiation laminated film and a zinc oxide layer b under the tin oxide layer. The zinc oxide layer a is a c-axis oriented polycrystalline substance, the zinc oxide layer b is a randomly oriented polycrystalline substance, and the tin oxide layer has a packing density of 90-95%.

Description

  The present invention relates to a low-emission laminate used as a window glass, and more particularly to a low-emission laminate having improved moisture resistance.

  In recent years, glass having heat insulating properties and heat shielding properties has been widely used for window glass for buildings or vehicles, and as such glass, low emission glass having a low emission film formed on the glass surface is used. Has been. Many of the low-emission films used for such low-emission glass have a film configuration of a ZnO film, an Ag film, and a ZnO film in order from the glass, and are actually used as low-emission glass for buildings and vehicles. When applied, it is usually applied as a double glazing or laminated glass.

  In the low emission film, the Ag film is an effective film as a functional layer that reflects heat rays. On the other hand, defects such as aggregation are likely to occur due to moisture in the atmosphere, and the low emission film is caused by the generated defects. Peeling, white turbidity, white spots, etc. may occur. As described above, when low-emission glass is used as a double-layer glass or laminated glass, the low-emission glass is simply used after the formation of the low-emission film until the process of forming a multi-layer glass or the process of forming a laminated glass. The plate may be stored for several days to several months, and there is a problem that the above-described defects occur during this storage period.

In order to improve the moisture resistance of the low radiation glass, for example, Patent Document 1 and Patent Document 2 disclose that the internal stress reduction of the uppermost oxide of the low radiation film is effective. As the oxide film, the use of a SnO ₂ film or a ZnO film to which other elements (Al, Si, B, Sn, Mg, Cr, etc.) having an ionic radius smaller than that of Zn ^{2+ in} an oxidized state is used. Patent Document 3 discloses a method of forming a metal oxide thin film such as a crystalline zinc oxide thin film in a gas atmosphere containing carbon dioxide gas in order to obtain an oxide film having low internal stress. . It is said that the metal oxide thin film obtained through this process is densified by aligning the crystal orientation of the film during film formation, and the internal stress of the thin film is reduced.

JP-A-4-357525 JP 2000-052476 A Japanese Patent Laid-Open No. 10-237630

K. Kato, H. Omoto, A. Takamatsu Optimum structure of metal oxide under-layer used in Ag-based multilayer Vacuum Vol. 83 (2009) 606-609 Introduction to X-ray reflectivity method Kenji Sakurai Kodansha Scientific G.G.Stoney The Tension of Metallic Films Deposited by Electrolysis Proceedings of the Royal Society of London.Series A Vol.82 (1909) 172-175

  As described above, in a low emission glass using an Ag film, a zinc oxide film with reduced internal stress is often used as a metal oxide thin film used for the uppermost layer. By using the zinc oxide film, It is possible to suppress the occurrence of defects derived from the Ag film, rather than using a zinc oxide film that does not reduce internal stress.

  As a result of studies by the present inventor, even with a low-emission film having improved moisture resistance using the above-described zinc oxide film, when the film surface is irradiated with light after long-term storage, the film surface looks patchy It was found that this defect occurs.

  Accordingly, an object of the present invention is to obtain a low emission glass having further improved stability during storage.

  As a result of the study by the present inventor, it has been clarified that the aforementioned spotted defects on the film surface are derived from a zinc oxide film formed on a substrate such as glass. Although the deterioration mechanism is unknown, the defect does not cause aggregation or the like unlike Ag, and the thickness of the zinc oxide does not change. As a result of further studies by the present inventors, a zinc oxide film having a random crystal orientation was formed on the upper layer portion of the low-emission film, and a tin oxide film was formed on the zinc oxide film so as to be the outermost layer. It has been found that the above-described defects can be suppressed by forming.

  That is, the present invention is a low radiation laminated body in which a low radiation laminated film is formed on a substrate, and the low radiation laminated film is a low radiation laminated film in which a low radiation laminated film is formed on a substrate. The low emission laminated film has a zinc oxide layer a on the substrate, an Ag layer on the zinc oxide layer a, a barrier layer on the Ag layer, and a tin oxide layer on the uppermost layer of the low emission laminated film. A zinc oxide layer b below the tin oxide layer, the zinc oxide layer a is a c-axis oriented polycrystalline body, and the zinc oxide layer b is a randomly oriented polycrystalline body, The tin oxide layer is a low radiation laminate having a packing density of 90 to 95%.

  Further, the low radiation laminate of the present invention is characterized in that the packing density of the zinc oxide layer b is 95% or more.

  Moreover, the low radiation laminated body of the present invention is characterized in that in the low radiation laminated film, a zinc oxide layer a is formed on the barrier layer, and an Ag layer is formed on the zinc oxide layer a.

  In the low emission laminate of the present invention, a barrier layer having at least one selected from the group consisting of zinc, titanium, niobium, aluminum, tin, nickel, and chromium is formed in the barrier layer. It is characterized by that.

Moreover, this invention is a manufacturing method which manufactures a low radiation | emission laminated body, the process of forming the zinc oxide layer a on a base material using a sputtering method, The process of forming an Ag layer on this zinc oxide layer a , O ₂ gas and CO ₂ to form a zinc oxide layer b in a mixed gas atmosphere containing a gas, the tin oxide layer under a mixed gas atmosphere containing O ₂ gas and CO ₂ gas onto the zinc oxide layer b Forming the step.

In the method for producing a low-emission laminate according to the present invention, the volume of O ₂ gas and the volume of CO ₂ gas in the mixed gas is calculated by [{CO ₂ / (CO ₂ + O ₂ )} × 100]. The volume concentration of CO ₂ gas is less than 50%.

A method of manufacturing a low-E laminate of the present invention is characterized by forming the zinc oxide layer a under O ₂ gas atmosphere.

  According to the present invention, it is possible to obtain a low emission glass excellent in storage stability in a high humidity environment.

Schematic of a sputtering apparatus. The cross-sectional schematic diagram showing one Embodiment of the low radiation film | membrane of this invention. The X-ray-diffraction figure of the zinc oxide layer a and the zinc oxide layer b. (A) Out-of-plane method, (b) In-plane method.

  The present invention is a low radiation laminated body in which a low radiation laminated film is formed on a substrate, and the low radiation laminated film includes at least a zinc oxide layer a, an Ag layer, a zinc oxide layer b, and the zinc oxide layer. a tin oxide layer formed on b;

  The substrate is preferably a transparent substrate (having a light-transmitting property for visible light), and an amorphous material in which a halo peak is observed by an X-ray diffraction method using CuKα rays is used. A material is preferably used. Examples of glass substrates include windows and mirrors for buildings and vehicles, float glass made of soda lime silicate glass used for displays, or manufactured by the roll-out method. Examples include soda-lime silicate glass and alkali-free glass such as alkali-free glass.

  For the plate glass, both colorless and colored can be used, and the shape of the substrate is not limited to a flat plate or a bent plate, and in addition to various tempered glass such as air-cooled tempered glass and chemically tempered glass. Netted glass can also be used. Furthermore, various glass substrates such as borosilicate glass, low expansion glass, zero expansion glass, low expansion crystallized glass, zero expansion crystallized glass, TFT glass, PDP glass, and optical filter base glass are used. be able to.

  Further, examples other than the glass substrate include amorphous resin substrates such as polyethylene terephthalate resin, polycarbonate resin, polycarbonate resin, polyvinyl chloride resin, and polyethylene resin.

  The zinc oxide thin film a is a layer formed on a base material, and is a c-axis oriented hexagonal wurtzite type polycrystal. It is more effective to interpose the zinc oxide thin film a between the Ag layer and the base material, thereby improving the adhesion between the base material and the Ag layer and preventing defects such as peeling of the Ag film. Is possible.

  The Ag layer is a layer formed on the zinc oxide layer a, and is used as a functional layer that reflects heat rays in the low emission film of the present invention. The thickness of the Ag layer is preferably about 7 to 22 nm. If the Ag layer is less than 7 nm or exceeds 22 nm, the low-emission laminate may not be able to achieve good radiation or good visible light transmittance.

  The zinc oxide layer b is a randomly oriented polycrystal and is formed under the uppermost tin oxide layer. The film thickness of the zinc oxide layer b is not particularly limited, but is preferably 10 to 40 nm.

  Moreover, the diffraction line from the zinc oxide (002) surface is obtained for the zinc oxide layer b by the out-of-plane measurement of the X-ray diffraction method using CuKα rays. In the zinc oxide layer b of the present invention, the maximum peak intensity If (cps: zinc oxide) of the diffraction line is determined by the film thickness (nm) and the maximum peak intensity Is of the halo indicated by the substrate (cps: transparent substrate). The divided number is 0.15 or less. Further, as a result of in-plane measurement of the X-ray diffraction method, the zinc oxide layer b can obtain diffraction lines from zinc oxide (100), (101), (002), (110) planes, etc. From this, it can be seen that zinc oxide b has a random orientation.

  A general zinc oxide thin film produced by sputtering has a columnar structure with c-axis orientation, but the internal stress is reduced compared to the conventional c-axis orientation zinc oxide layer due to the random orientation of the crystal orientation. Become a film. Further, as described above, since the randomly oriented zinc oxide layer is used as the upper layer, it is possible to suppress the penetration of moisture and the like and prevent the Ag layer formed in the lower layer from deteriorating.

The tin oxide layer formed on the zinc oxide layer b is an amorphous film formed on the uppermost layer of the low radiation laminated film, and the filling density is 90 to 95%. Incidentally, the packing density is ₀ the theoretical density _[rho, when the measured density was ρ (ρ / ρ ₀₎ is a value represented by × 100. A tin oxide layer having a filling density in the above range has a lower internal stress than when formed on the zinc oxide layer a, for example, and can suppress the occurrence of defects in the Ag layer formed in the lower layer. .

  The thickness of the tin oxide layer is preferably 5 nm or more. If it is less than 5 nm, it may be difficult to obtain good moisture resistance.

Moreover, the oxidation state of the tin oxide layer may be uniform or non-uniform, and examples thereof include SnO ₂ and SnO _2-x (0 ≦ x <1). When x ≧ 1, the transparency of visible light may be significantly impaired.

  Zinc oxide on a base material that could not be prevented only by suppressing defects in the Ag layer by forming the structural unit in which the tin oxide layer was formed on the zinc oxide b layer in the uppermost layer of the low radiation laminated film It became possible to suppress defects originating in the layer.

  The zinc oxide layer a and the zinc oxide layer b may contain 1 to 10% by weight of at least one of Al, Sn, B, Si, In, Mg and Ga as a composite oxide.

  One of the preferred embodiments of the present invention is a zinc oxide layer a, an Ag layer on the zinc oxide layer a, and a barrier layer on the Ag layer. A low-emission laminated body in which a zinc oxide layer b is formed on the uppermost barrier layer and a tin oxide layer is formed on the zinc oxide layer b.

  When repeating the structural unit consisting of three layers of the zinc oxide layer a, the Ag layer, and the barrier layer two or more times, the zinc oxide layer a to be stacked next may be stacked on the barrier layer, Another layer may be formed between the barrier layer and the zinc oxide layer a to be laminated next. In the above-described structural unit, the upper limit of the number of times of lamination is not particularly limited. However, when used for vehicles and buildings, low radiation that is laminated about 2 to 3 times is considered from the viewpoint of both visibility and low radiation performance. It is preferable to use a laminated film.

  The barrier layer is formed on the Ag layer to prevent the Ag layer from being oxidized when the oxide layer is formed above the Ag layer, and has a thickness of 0.5 to 3 nm. Is preferred. If the film thickness is less than 0.5 nm, the Ag layer may be oxidized, and it is insufficient to protect the Ag layer. On the other hand, if it exceeds 3 nm, the visible light transmittance may be impaired. The barrier layer may be appropriately selected so as not to impair the various properties of the low-emission laminated film. For example, the barrier layer includes at least one selected from the group consisting of Zn, Ti, Nb, Al, Sn, Ni, and Cr. And metal films, alloy films, metal oxide films, metal nitride films, and the like.

  The low-emission laminate is, for example, used for construction, and has a visible light transmittance of 60% or more, a solar heat gain rate of 0.4 or less, and a vertical emissivity of 0.05 or less in a multilayer glass. Is preferred. Further, when used for vehicles, visibility is strongly required, and at least the visible light transmittance is preferably 70% or more. What is necessary is just to select suitably the film thickness of each layer of a low radiation | emission laminated film, and the number of layers, in order to obtain the said desired value.

  The low emission laminate of the present invention is preferably formed using a vapor deposition process such as sputtering. FIG. 1 will be described in detail in an embodiment described later. In addition to sputtering, electron beam evaporation, ion beam deposition, ion plating, or the like may be used for the evaporation process. In the present invention, various known sputtering methods such as magnetron sputtering, bias sputtering, ECR sputtering, and counter sputtering can be applied.

  The atmosphere gas at the time of film formation may be appropriately selected according to the desired film, and suitable atmosphere gases for each layer will be described later. The upper limit of the pressure of the atmospheric gas during film formation is preferably 1.0 Pa, and the lower limit is not particularly limited, but may be set to 0.1 Pa. When the pressure of the atmospheric gas exceeds 1.0 Pa, the film formation rate is remarkably reduced, so that the production tact may be reduced.

  Moreover, in the zinc oxide layer a layer and the Ag layer of the present invention, if the atmospheric gas pressure exceeds 1.0 Pa, the sputtered particles cannot sufficiently migrate on the substrate, so that the crystallinity of zinc oxide and Ag is low. And low radiation performance may be reduced.

One of the preferred embodiments of the present invention includes a step of forming a zinc oxide layer a on a substrate using a sputtering method, a step of forming an Ag layer on the zinc oxide layer a, and an O ₂ gas. CO ₂ forming a zinc oxide layer b in a mixed gas atmosphere containing a gas, forming a O ₂ gas and CO tin oxide layer under a mixed gas atmosphere containing ₂ gas on the zinc oxide layer b, It is a manufacturing method of the low radiation laminated body which has this.

The zinc oxide layer a is prepared by adjusting the atmospheric gas during film formation by using a Zn target as a target or an alloy target having a metal such as Al, Sn, B, Si, In, Mg and Ga as Zn. can get. The zinc oxide layer a is an underlayer film of the Ag layer. When the c-axis orientation of the zinc oxide is strong and the compressive stress acting on the zinc oxide is high, the lattice mismatch with the Ag layer is reduced, and the conductivity of the Ag layer is reduced. Therefore, it is preferable to form a film in an environment where the O ₂ gas is 100% by volume. Also (see Non-Patent Document 1), no harm in using a mixed gas, O ₂ gas is preferably 80 vol% or more. In the present invention, since a zinc oxide layer having a strong c-axis orientation can be obtained without intentionally heating the substrate, it is not particularly necessary to perform operations such as heating the substrate.

  When forming the Ag layer, it is desirable to exhaust the oxidizing gas in the chamber in order to prevent Ag from being oxidized. At the time of film formation, in order to prevent oxidation, nitridation, and the like of the Ag film and perform stable production, it is preferable that the Ar gas is in an environment of 100% volume. In addition to Ar, a rare gas such as He, Xe, Kr, or Ne can be used. An Ag target is preferably used as the target, and an alloy target to which a different metal such as Pd, Nd, or Au is added in addition to Ag may be used.

  After forming the Ag layer, it is preferable to form a barrier layer on the Ag layer. The barrier layer is preferably formed using a desired metal target, metal oxide target, or the like in an atmosphere that does not contain an oxidizing gas.

The zinc oxide layer b is formed in an atmosphere containing a gas such as CO ₂ or CO using a Zn target as a target or an alloy target having a metal such as Al, Sn, B, Si, In, Mg and Ga in Zn. It is preferable to form by. By using these gases, it is possible to reduce the crystallinity of zinc oxide without reducing the packing density of the film and to make the zinc oxide have a random orientation. As the atmospheric gas, CO ₂ gas is useful in terms of safety and cost, and CO calculated by [{CO ₂ / (CO ₂ + O ₂ )} × 100] of the volume of O ₂ gas and the volume of CO ₂ gas. _It is preferable to form a film in a mixed gas atmosphere in which the volume concentration of the _two gases is less than 50% and 1% by volume or more. Even if the film is formed at 50% by volume or more, a good film can be obtained, but the film may not be sufficiently oxidized and may have a large absorption. Moreover, crystallinity may not fully fall that it is less than 1 volume%.

Although the tin oxide layer is formed on the zinc oxide layer b by using an Sn target as a target or an alloy target having a metal such as Zn or In as Sn, a film with reduced internal stress is obtained. By forming a film in an atmosphere containing CO ₂ gas as in the case of the zinc oxide layer b, it is possible to obtain an amorphous film with further reduced internal stress. When forming the tin oxide film, it is preferable to form the CO ₂ gas at less than 50% by volume and at least 20% by volume. Even if the film is formed at 50% by volume or more, a good film can be obtained, but the film may not be sufficiently oxidized and may have a large absorption. Further, if it is less than 20% by volume, reduction of internal stress may be insufficient.

Example 1
A low emission laminate in which thin films are laminated in the order of ZnAlO / Ag / ZnAl / ZnAlO / Ag / ZnAl / ZnAlO / Ag / ZnAl / ZnAlO / SnO ₂ on the transparent substrate 3 is schematically shown in FIG. It was produced using a DC magnetron sputtering apparatus having a structure. As the transparent substrate 3, soda lime silicate glass was used.

  First, after setting the target in the chamber and holding the transparent base material 3 on the base material holder 2, the inside of the vacuum chamber 8 was evacuated using the vacuum pump 5. After evacuation, the atmosphere gas at the time of sputtering film formation was introduced into the vacuum chamber 8 from the gas introduction tube 7 and the gas flow rate was adjusted by a mass flow controller (not shown). The pressure in the vacuum chamber 8 was adjusted by the open / close valve 6 and the output power of the DC power source was 1 kW.

  Next, the substrate holder 2 was transported onto the transport roll 12 and passed next to the target 1. The passing speed at this time was manipulated and adjusted so that a desired film thickness was obtained for each layer. Moreover, the said low radiation | emission laminated body was obtained by conveying the front of the target 1 which desires the transparent base material 3 suitably. In addition, the substrate was not intentionally heated.

  In addition, a ZnAl (Al 2 wt% -containing Zn) target is used as the upstream target 1 for preparing the zinc oxide layer a and the zinc oxide layer b, an Ag target is used as the downstream target 1, and a downstream target is used for preparing the barrier layer. 1 was a ZnAl (Al 4 wt% -containing Zn) target, and an Sn target was installed on the most downstream target 1. The film forming conditions for each layer are described below.

First, a ZnAlO film was formed as a first zinc oxide layer a on the substrate. The atmospheric gas introduced into the vacuum chamber 8 had an O ₂ flow rate of 100% by volume, a pressure of 0.3 Pa, and a film thickness of 35 nm.

Next, a first Ag layer was formed. First, after evacuating the O ₂ gas in the vacuum chamber 8 in which the Ag target is installed, Ar gas is introduced into the vacuum chamber 8 from the gas introduction pipe 7 while being controlled by the mass flow controller, and the pressure is set to 0.3 Pa. It was. The output power of the DC power source was 0.4 kW. The Ag layer had a thickness of 10 nm.

  Next, a ZnAl layer was formed as a first barrier layer. Ar gas was introduced into the vacuum chamber 8 from the gas introduction pipe 7 while being controlled by a mass flow controller, and the pressure was set to 0.5 Pa. The output power of the DC power source was set to 0.12 kW. The film thickness of the ZnAl layer was 2.7 nm.

Next, a ZnAlO thin film was formed on the ZnAl layer as the second zinc oxide layer a. At this time, the O ₂ flow rate was 100% by volume, the pressure was 0.3 Pa, and the film thickness was 75 nm.

  Next, a second Ag layer was formed in the same manner as the first Ag layer.

  Next, a second barrier layer was formed in the same manner as the first barrier layer.

Next, a ZnAlO thin film was formed on the ZnAl layer as the third zinc oxide layer a. At this time, the O ₂ flow rate was 100% by volume, the pressure was 0.3 Pa, and the film thickness was 74 nm.

Next, a third Ag layer was formed. After exhausting the O ₂ gas in the vacuum chamber 8 in which the Ag target was installed, Ar gas was introduced into the vacuum chamber 8 from the gas introduction pipe 7 while being controlled by the mass flow controller, and the pressure was set to 0.3 Pa. . The output power of the DC power source was 0.4 kW. The Ag layer had a thickness of 14 nm.

  Next, a third barrier layer was formed in the same manner as the second barrier layer.

Next, a ZnAlO thin film was formed as zinc oxide b. At this time, Ar gas in the vacuum chamber 8 was exhausted, and then O ₂ and CO ₂ gas were introduced from the gas introduction pipe 7. The gas flow rate is controlled by a mass flow controller (not shown), the CO ₂ flow rate ratio [{CO ₂ / (O ₂ + CO ₂ )} × 100] is 20% by volume, the pressure is 0.3 Pa, and the film thickness is The thickness was 35 nm.

Next, a tin oxide layer was formed. At this time, O ₂ and CO ₂ gas in the vacuum chamber 8 were exhausted, and then O ₂ and CO ₂ gas were introduced from the gas introduction pipe 7. The gas flow rate was controlled by a mass flow controller (not shown), and the CO ₂ flow rate ratio [{CO ₂ / (O ₂ + CO ₂ )} × 100] was set to 45% by volume. The pressure in the vacuum chamber 8 during film formation was adjusted to 0.3 Pa by the opening / closing valve 6, and the film thickness was 10 nm.

Comparative Example 1
Example except that the atmosphere gas at the time of film formation was changed to 100% O ₂ flow ratio instead of the zinc oxide layer b and the atmosphere gas at the time of film formation of the zinc oxide layer a and the tin oxide layer was changed to 100% O ₂ flow ratio. A low emission laminate was obtained by the same procedure as in 1.

Comparative Example 2
Instead of the zinc oxide layer b, a low-emission laminate was obtained in the same procedure as in Example 1 except that the zinc oxide film a was obtained with the O ₂ flow rate ratio of 100% as the atmospheric gas during film formation.

  Each evaluation method is described below.

(1) X-ray diffraction The crystal structure of the zinc oxide thin film was evaluated by an X-ray diffraction method using CuKα rays. The orientation in the vertical direction relative to the substrate was evaluated using the out-of-plane method, and the orientation in the horizontal direction relative to the substrate was evaluated using the in-plane method.

  FIG. 3 shows X-ray diffraction patterns of the zinc oxide layer a and the zinc oxide layer b. The figure shows that the zinc oxide layer a has a c-axis oriented polycrystalline structure, while the zinc oxide layer b has a randomly oriented polycrystalline structure.

(2) Packing density When the theoretical density of the tin oxide thin film was ρ ₀ , and the measured density was ρ, the value represented by (ρ / ρ ₀ ) × 100 was taken as the packing density. The theoretical density ρ ₀ of the tin oxide thin film is 7.077 g / cm ³ (adopted in the value published in JCPDS card number 03-1114), and the measured density ρ is a critical angle measured by the X-ray reflectivity method. It is obtained by analyzing this. The density measurement by the X-ray reflectivity method is introduced in detail in Non-Patent Document 2, and can be derived by a general-purpose analysis program attached to the XRD measurement apparatus (RINT-UltimaIII manufactured by Rigaku). Table 1 shows the packing density of the zinc oxide layer a, the zinc oxide layer b, and the tin oxide layer.

(3) Internal stress The internal stress of the thin film was evaluated by the cantilever method. This method is a method for determining the internal stress of the film by measuring the amount of change in the warpage of the substrate before and after film formation. In order to perform this evaluation, the base material was a microsheet glass of 8 cm × 10 cm × 0.1 mmt, and a zinc oxide thin film and a tin oxide thin film were formed under the same conditions as in Example 1 and Comparative Examples 1 and 2. However, only one end of the glass substrate was fixed to the substrate holder 2.

  When a thin film is formed under such conditions, warpage occurs in the base material in accordance with internal stress generated in the thin film, and as introduced in Non-Patent Document 3, the internal stress of the thin film is obtained from the amount of warpage. . Table 1 shows internal stresses of the zinc oxide layer a, the zinc oxide layer b, and the tin oxide layer.

(4) Moisture resistance of the low-radiation laminate The transparent substrate on which the thin-film laminate is formed is held for 8 weeks in an environment of a temperature of 30 ° C. and a relative humidity of 90%, and is 20 cm square (20 cm × 20 cm = 400 cm ² ). The number of defects having a diameter of 0.3 mm or more generated in the region was measured. The number of samples was 3.

  Table 1 shows the relationship between the test period and the number of defects in Example 1 and Comparative Examples 1 and 2. From Table 1, after 8 weeks in Comparative Example 1, the average number of defects is as large as 10, and defects appearing patchy when light is applied to the film surface. In the desired high durability low radiation laminate, There wasn't. In Comparative Example 2, the number of defects decreased compared to Comparative Example 1, but the number of defects increased with time, and when the film surface was exposed to light, defects appearing in spots were also generated. It was not a low-radiation laminate having sufficient durability.

  On the other hand, in Example 1, in addition to the decrease in internal stress of the tin oxide layer, the orientation of the zinc oxide layer is random. When the moisture resistance test was conducted, the average number of defects was 1 or less even after 8 weeks had passed, there was almost no change in the number of defects over time, no patchy defects were generated, and the storage stability was excellent. It was found to be a low emission laminate.

DESCRIPTION OF SYMBOLS 1 Target 2 Base material holder 3 Base material 4 Magnet 5 Vacuum pump 6 On-off valve 7 Gas introduction tube 8 Vacuum chamber 9 Power cord 10 Power source 11 Backing plate 12 Transport roll 13 Zinc oxide layer a
14 Ag layer 15 Barrier layer 16 Zinc oxide layer b
17 Tin oxide layer 18 Multilayer film

Claims (7)

A low-emission laminated film in which a low-emission laminated film is formed on a substrate, the low-emission laminated film comprising a zinc oxide layer a on the substrate, an Ag layer on the zinc oxide layer a, and the Ag layer A barrier layer, a tin oxide layer as an uppermost layer of the low radiation laminated film, a zinc oxide layer b as a lower layer of the tin oxide layer, and the zinc oxide layer a is a c-axis oriented polycrystal The zinc oxide layer b is a randomly oriented polycrystalline body, and the tin oxide layer has a filling density of 90 to 95%. The low-radiation laminate according to claim 1, wherein a filling density of the zinc oxide layer b is 95% or more. 3. The low radiation laminated body according to claim 1, wherein in the low radiation laminated film, a zinc oxide layer a is formed on the barrier layer, and an Ag layer is formed on the zinc oxide layer a. . The said barrier layer has at least one chosen from the group which consists of zinc, titanium, niobium, aluminum, tin, nickel, and chromium, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The low-emission laminate described in 1. A manufacturing method for manufacturing the low-emission laminate according to any one of claims 1 to 4, wherein the zinc oxide layer a is formed on a substrate using a sputtering method, and the zinc oxide layer forming a Ag layer on a, forming an O ₂ gas and CO zinc oxide layer b under a mixed gas atmosphere containing ₂ gas, the O ₂ gas and CO ₂ gas onto the zinc oxide layer b And a step of forming a tin oxide layer under a mixed gas atmosphere. The mixed gas has a volume concentration of CO ₂ gas calculated by [{CO ₂ / (CO ₂ + O ₂ )} × 100] of the volume of O ₂ gas and the volume of CO ₂ gas is less than 50%. The manufacturing method of the low radiation laminated body of Claim 5 characterized by the above-mentioned. The method for producing a low-emission laminate according to claim 5 or 6, wherein the zinc oxide layer a is formed in an O ₂ gas atmosphere.

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