Process for the treatment of metal oxide or nitride thin films.

[0001] The present invention relates to a method for treating a thin layer containing one or more metal oxides, nitrides, oxynitrides, acid carbides, more specifically, a transparent substrate. In particular, it relates to a method for producing such a layer, which is deposited directly on the glass or by interposing another layer by a method using a vacuum.

[0002] The present invention also relates to applying this method to the manufacture of windowpanes.

[0003] [Problems to be Solved by Conventional Techniques and Inventions] At present, for the purpose of manufacturing window glass, which is positioned as "functionality", it is thin on at least a part of a generally composed base material. Laminations of layers or thin layers are deposited to impart optical properties such as antireflection properties, infrared light properties (low emissivity), and / or electrical conductivity properties to the window glass. Layers containing metal oxides and / or nitrides are most commonly used, eg as dielectrics on either side of the low radiation layer of silver or doped metal oxides, or have high and low reflectance. Used as an interfering film with alternating laminates of oxides or nitrides.

[0004] However, there is a problem with the chemical and / or physical reliability of these films or their laminates, which is a monolithic windowpane where the coating substrate is exposed directly to attack from the ambient atmosphere. It becomes serious when it is used for. Further, even when the base material is to be formed as a part of a multiple window glass (double window glass, laminated window glass), it is exposed to attacks by various handlings in various manufacturing processes of the window glass.

[0005] For example, as described in the document "" Ion-based methods for optical thin film deposition "(Journal of Material Science; JP Martin, 21 (1986) 1-25)", IDA (Ion-Assisted) is used as an experimental technique. Deposition) is known, and it is possible to modify the structure of a thin oxide layer by depositing using an ion beam. This method deposits layers by evaporation while exposing the layers to oxygen or argon ion bombers throughout during deposition. Bomberdment makes it possible to increase consolidation and bondability to carry substrates, but this phenomenon has not yet been fully explained. However, this type of assisted deposition is very complex to implement and is actually only applicable to very small size substrates, the problem is that one is the ion beam and the other is very local. It is a matter of convergence of particles that evaporate from a target source and generate a layer on the substrate.

[0006] In addition, French patent application EPO-A-0328257 describes a technique for depositing an oxide layer by cathode sputtering, the purpose of which is to accelerate the deposition rate by the following operations: first in an inert atmosphere. The metal layer is transformed into a metal oxide layer by depositing the metal layer with a suitable metal target in and then exposing it to an ion source capable of generating a plasma of oxidizing ions. Therefore, this ion source contributes to the chemical oxidative change in this case, and the intended use is essentially optical glass, not window glass.

[0007] Here, an object of the present invention is to develop a method for treating a thin layer containing one or more metal oxides, nitrides, oxynitrides, or acid carbides, and the layers are chemically and / or physically. An object of the present invention is to provide a treatment method that can be carried out on an industrial scale without being restricted by the above-mentioned drawbacks, that is, the size of the base material. An object of the present invention is a layer of one or more metal oxides, nitrides, nitrides, or acid carbides deposited on a transparent substrate, in particular glass, in particular a magnetic field, and preferably oxygen and. / Or the provision of a method of treating by a cathode sputtering technique utilizing a reactive atmosphere in the presence of nitrogen, which method involves exposing the deposited layer to a "low energy" ion beam.

[Means and Effects for Solving Problems] The "low energy" ion beam referred to in the present invention is selected so as to limit the sputtering of the layer formed under the collision of the ions of the beam as much as possible. It should be understood that the beam has different parameters. Of course, this concept should take into account the inherent sputtering rates for each material of interest.

[0009] The treatment according to the invention makes it possible to improve the physical and / or chemical durability of these layers in particular, and this improvement can be specifically linked to an increase in the index of refraction. The layers treated by the present invention, in particular, have less surface wrinkles than standard layers deposited by cathodic sputtering, which can be explained by both the formation and the specific "smoothing" of the surface. This latter property can further suitably promote good bonding and good wetting of layers later deposited on such treated layers.

[0010] We surprisingly use cathode sputtering, a deposition technique that is perfectly suited to the industrial requirements for the production of large glazings of any size, and further relate treatment with ion beams. Reached the intended purpose. It is possible to completely separate the deposition process and the ion beam processing process. Therefore, this separation eliminates all the problems that arise in the auxiliary deposition method, making it easy to carry out the process as long as the deposition is carried out with industrially established techniques and the ion beam processing is carried out continuously on the same device. To do.

[0011] It is also possible to simultaneously carry out layer deposition and its treatment with an ion beam. With respect to the process, this is a little more difficult to achieve, but easier to implement than evaporation-type deposition techniques, because the sputtering method uses a material source of a properly sized target near the substrate to be coated. To do. Therefore, good convergence between the particles emanating from the target and the ions emanating from the beam and reaching the coated substrate is likely to be obtained. This at the same time enables the effectiveness of ion beam treatment over the entire layer thickness, which should be guaranteed as wide a range as possible.

[0012] Here, one of the preferred embodiments of the present invention comprises depositing layers in a continuous manner and having at least one of the continuous deposition steps followed by at least one step of ion beam treatment. It consists of. Preferably, deposition and ion beam treatment can be performed alternately and regularly. If the desired final thickness is at least about 30 nanometers, a series of continuous deposits is determined or desired to deposit layers, preferably on the order of 5-30 nanometers, more preferably 15-20 nanometers. If the final thickness of the is thinner, it can be determined to be on the order of 5 nanometers, and then these continuous deposits can be switched to ion beam treatment. In this way it is possible to optimize the effectiveness of the ion beam and make the layers as dense as possible. In practice, the thickness deposited during each of the continuous steps, the regularity of the beam, the nature of the layer, the final thickness of the layer, the desired physical and mechanical performance, and the industrial requirements are properly considered. In general, each treatment time with an ion beam is preferably less than 30 minutes, more preferably 1-10 minutes.

[0013] Further, if a pretreatment such as exposing a bare base material to an ion beam before deposition is performed, the adhesion between the layer and the base material can be improved. The characteristics of the ion beam are very important. For the deposition of oxides, oxynitrides and acid carbides, it is preferable to use a beam in which at least some of the ions are oxidizing, such as ionized oxygen. However, especially in the case of nitride deposition, at least some of the ions can be, for example, a beam of ionized argon or ionized nitrogen.

[0014] The energy of the so-called "low energy" beam is low enough not to oversputter the layer to be treated, as described above, and at the same time the layer can be effectively made highly durable by the impact of ions. Should be high enough. Also, the energy value should match the thickness of the layer with which the ion beam collides, and the ease of sputtering of the material forming the layer. Specifically, the energy value of the ion when colliding with the layer is preferably 500 electron volt (eV) or less, more preferably 200 eV or less, specifically 200 to 50 eV, and particularly about 80 to 100 eV. is there.

Similarly, the ion density of the ion beam is preferably about 1 to several milliamperes / cm.²Is adjusted to be. Specifically, the method of the present invention can be applied to a layer of titanium oxide or tantalum oxide, a layer of zinc oxide or tin oxide, a layer of silicon oxide or silicon nitride, or a layer of titanium nitride. Also, an object of the present invention includes providing a device for carrying out this method, the device being at least one electrode with a suitable target, at least one ion beam source such as an ion gun, and only one. Alternatively, a sputtering container divided into two is provided. In the case of separate containers, the pressure and atmosphere conditions of each container can be selected slightly differently or exactly the same.

The substrate can be movably attached to the target and gun, the substrate is continuously coated with a thin layer by sputtering from the target and then processed by the beam generated by the beam source. Can be done. As described above, the device for carrying out the present invention includes, for example, a container in which cathodes and ion guns are alternately arranged, and the base material moves in a linear, continuous, and horizontal state with respect to the device. When deposition and beam processing are performed simultaneously, the cathode with the target and the ion beam source are placed in an appropriate state with respect to the substrate so that the particles and the ions of the beam emitted from the target converge appropriately.

[0017] The present invention also aims to produce a layer that is hard or durable and / or dense and / or particularly less wrinkled on the surface than a layer deposited by mere cathode sputtering. Therefore, these layers can be used in the manufacture of window glass. Other objects of the invention will become apparent from examples (but not limited to) aspects of the invention and the accompanying figures.

[Example] All of the examples are 15 × 10 cm using a cathode sputtering apparatus using a reactive atmosphere containing oxygen and a magnetic field.²It involves the continuous deposition of thin layers based on titanium oxide, tantalum oxide, tin oxide and silicon oxide on a transparent silicon sodium calcium glass substrate of the size of. The targets to be sputtered are titanium, tantalum, tin, or doped silicon, respectively, and the vertical cathode is 210 mm long x 90 mm wide. The glass substrate can be mounted on a rotary conveyor and can move vertically, allowing alternating sputtering deposition of the target and ion beam treatment of the deposited layer, with the beam perpendicular to the substrate. It is fired from an ion gun (sold under the trade name Commenwealth Mark II by Commenwealth Scientific) placed in. This type of gun fires a beam of oxygen ions in this case, and the ion density measured 15 cm from the source is about 1.2 mA / cm.²Is. During the process, the substrate is placed approximately 14 cm from the beam launch point.

[0019] In the following example, at least 0.7 mA / cm of energy of 60 eV or less before performing any processing.²The base material was pretreated by exposing the base material to an oxygen ion beam having an ion density of 1 for 1 minute. For the evaluation of the chemical and physical durability of the layers treated according to the present invention, these layers are subjected to two types of tests in the smallest example, a test to evaluate the wear resistance of the layers known as the taper test. Served. This is done using a grindstone in which the abrasive particles are embedded in an elastomer. This tester is manufactured by Taber Instrument of the United States and is a standard wear tester of model 174. The grindstone is CS10F and the load is 500 grams. The layer is exposed to 650 rotations. Abrasion is the reflection of light with a wavelength of 550 nm R_LIt is measured by the gradual decrease of.

A test known as the HCl test involves immersing a substrate coated in an aqueous HCl solution at a concentration of 1 mol / liter and heating to 100 ° C. until the layer deteriorates. This is also R_LIt is expressed by the decrease of. The results of some of these tests are summarized in the attached figure. In addition, the surface state of the layer was analyzed with an electron microscope. Here, the wrinkles on the surface in an area of 1 micron square can be quantified by the root mean square or the root mean square of the fluctuation, and expressed in angstrom units.

【0021】<u style="single">Example 1</u>60eV energy and 0.7mA / cm²The substrate was pretreated with a beam of ion density. Three consecutive deposits at 15 nm were performed to deposit a layer of titanium oxide with a thickness of 45 nm. Each deposition was carried out under the following conditions.

[0022] -Pressure: 0.264 Pa (2 x 10)^-3Thor) Atmosphere: Argon / oxygen, oxygen 15% by volume Power supply: 2.4 watts / cm²After each of these deposits, treatment with an oxygen ion beam was performed under the following conditions. Energy of ions colliding with the layer: 84eV Ion density: 1.2mA / cm²-Treatment time: The layer obtained for 5 minutes is dense, the refractive index is 2.45, which is a significant increase, and TiO of the same thickness deposited under the same conditions except that the ion beam is not treated.₂Layer (hereinafter referred to as "standard") had a refractive index of 2.37. The surface roughness was fairly small, with the root mean square of wrinkles reaching only 14 angstroms (1.4 nanometers), while the standard layer reached 35 angstroms (3.5 nanometers).

[0023] FIGS. 1 and 2 show standard TiO.₂The results of the taper test and the HCl test for the layer (curve C1) and example 1 (curve C2) are shown below. In Fig. 1, the abscissa is the rotation speed of the wear tester, and the ordinate is the light reflection value R._L%. In Figure 2, the abscissa is time and the ordinate is R._LIs the value of. These figures clearly show that the layer of Example 1 is significantly more resistant to mechanical wear and acid attack than the standard layer.

【0024】<u style="single">Example 2</u>Under the same pretreatment conditions, 6 consecutive deposits and 6 beam treatments were performed alternately to deposit a titanium oxide layer with a thickness of 900 nm. The layers treated in this way were dense, with a refractive index of 2.52 and a standard layer of the same thickness at 2.37. The wrinkles were also significantly reduced, with the root mean square surface wrinkles being only 2.6 angstroms (0.26 nanometers), while the standard layer was 35 angstroms (3.5 nanometers) squared.

【0025】<u style="single">Example 3</u>The energy is adjusted to 45eV and the ion density is 1.4mA / cm.²The base material was pretreated using the beam of. A 15 nm thick titanium oxide layer was then deposited, each with 3 consecutive deposits at 5 nm and 3 ion beam treatments alternately under the same conditions as in the previous example. Standard TiO of the same thickness deposited by cathode sputtering without ion beam treatment for chemical resistance₂Evaluated by performing an HCl test compared to the layer.

After 8 minutes, the standard layer completely collapsed and the measured R_LWas the same as that of bare glass. In contrast, the layers treated according to the present invention were durable and did not completely disintegrate after 2 hours (R after 2 hours)._LIs 9.3%).<u style="single">Example 4</u>A 25 nm tantalum oxide layer was deposited as a single deposit. The deposition was carried out under the following conditions.

[0027] -Pressure: 0.264 Pa (2 x 10)^-3Thor) Atmosphere: Argon / Oxygen, Oxygen 30% by volume Power supply: 1.45 watts / cm²After this deposition, treatment with an oxygen ion beam was performed under the following conditions. Energy of ions colliding with the layer: 84eV Ion density: 1.2mA / cm²-Treatment time: 5 minutes The treatment layer was dense. The root mean square of surface wrinkles was 1.9 angstroms (0.19 nm), and the root mean square of tantalum pentoxide of the same thickness deposited by the same method, except untreated, was 4.1 angstroms (0.41 nm).

【0028】<u style="single">Example 5</u>Energy is 45eV and ion density is 1.4mA / cm²The substrate was pretreated for 1 minute using the beam of. Tin Oxide SnO₂A layer with a final thickness of 30 nm was deposited by three consecutive deposits of 23 nm each under the following conditions.

[0029] -Pressure: 0.2Pa (1.5 x 10)^-3Thor) Atmosphere: Argon / Oxygen, Oxygen 69% by volume Power supply: 0.9 watts / cm²After each deposition, treatment with an oxygen ion beam was performed under the following conditions. Energy of ions colliding with the layer: 84eV Ion density: 1.9mA / cm²-Treatment time: The layer obtained for 3 minutes was cured to a very remarkable degree and showed exceptional chemical resistance. This layer and standard SnO with a thickness of 30 nm deposited in the sputtering process without ion beam treatment.₂The layer was subjected to an HCl test. The whole standard layer collapsed after 30 minutes, but the layer according to the invention showed no significant evidence of collapse even after 48 hours.

The tin oxide layer, which is known to have a high sputtering rate, is more likely to be reatomized (resputtered) because a layer of only 30 nm was finally obtained after three depositions at 23 nm. Should be noted. Here, for an ion beam of the same energy (84 eV), it has been confirmed that the action of resputtering with more or less treated layers is due to the substance in question. Limited resputtering produces no significant adverse results other than the cost of the raw material, and the tin oxide cost in this example is not unreasonable.

【0031】<u style="single">Example 6</u>The base material was pretreated in the same manner as in Example 5. Then, using high frequency, under the following conditions, 30 nm tin oxide SnO doped with boron (several%)₂Was deposited in a single operation. Pressure: 0.2Pa (1.5 × 10)^-3Thor) Atmosphere: Argon / Oxygen, 30% by volume of oxygen Power supply: 2.6 watts / cm²After each deposition, treatment with an oxygen ion beam was performed under the following conditions.

-Energy of ions colliding with the layer: 60 eV-Ion density: 2.2 mA / cm²-Treatment time: 5 minutes It was found that the layer treated in this way was more durable, especially chemical resistant, specifically alkali resistant.

【0033】<u style="single">Example 7</u>The base material was pretreated in the same manner as in Example 6. Boron-doped 20 nm thick silicon oxide SiO in the same manner as above₂Layers were deposited by two consecutive deposits every 20 nm. Every two deposits were treated with an oxygen ion beam under the same conditions as in Example 6. Again, the durability of the layer was significantly improved.

[0034] Mass spectrometric measurement was performed by a SIMS device (secondary ion mass spectrometry). One is a 40 nm thick boron-doped SiO deposited by a single operation without the treatment shown in Figure 4.₂The other is the layer of Example 7 in FIG. In FIGS. 3 and 4, the abscissa is the micron thickness of the layer in question. The ordinates represent the intensity of secondary ions, expressed in collisions, measured per second in the usual way.

[0035] In the figure, the curve of Si corresponds to the silicon content in the oxide. In Figure 3, it is clear that the Si curve has a certain deflection in the middle of the layer thickness, which is a kind of interface (some interface) between the layers deposited in each of the two continuous deposits. interface) indicates that there is. Unlike this, Figure 4 does not show this type of deflection.

[0036] Thus, this is a proof that the layers deposited and treated according to the present invention can be structurally modified and retain their treated traces, at least in the shallow layers of the interface during continuous deposition. Yes (the curves of Aluminum Al and Tungsten W indicate that impurities are simply present in the sputtering vessel, which would not appear using other types of depositors).

[0037] In summary, the method according to the invention is one or more metal oxides, nitrides, oxynitrides without imposing constraints that make it impractical in application to continuous production on large size substrates. It makes it possible to significantly improve the durability of thin layers containing acid carbides. This hardening is probably due to a combination of the phenomenon of densification within the thickness of the layer and the surface modification of the layer, such as smoothness.

[0038] Further, since this method can be optimized independently by performing the deposition operation and the ion beam treatment independently, the flexibility of implementation is higher than that of the method of performing the deposition and the ion beam at the same time. Extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1] FIG. 1 is a graph showing the results of a taper wear test.

FIG. 2 is a graph showing the results of an HCl test.

FIG. 3 is an ion beam-treated SiO.₂It is a mass spectrum of a layer.

FIG. 4 is SiO not treated with an ion beam.₂It is a mass spectrum of a layer.