JP5416683B2 - Touch panel sensor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a touch panel sensor having a transparent conductive film and wiring connected to the transparent conductive film.

  The touch panel sensor, used as an input switch integrated with the image display device, is located on the front of the image display device. Due to its ease of use, the touch panel sensor is widely used for bank ATMs, ticket vending machines, car navigation systems, PDAs, and copy machine operation screens. It is used. Examples of the input point detection method include a resistance film method, a capacitance method, an optical method, an ultrasonic surface acoustic wave method, and a piezoelectric method. Of these, the resistive film type and the capacitive type are most widely used because they are not costly and have a simple structure.

  A resistive film type touch panel sensor is roughly divided into an upper electrode, a lower electrode, and a tail part. A transparent conductive film provided on a substrate (for example, a film substrate) constituting the upper electrode, and a lower electrode are provided. The transparent conductive film provided on the board | substrate (for example, glass substrate) to comprise comprises the structure which opposed the spacer. When the film surface of the touch panel sensor having such a configuration is touched with a finger or a pen, the two transparent conductive films are in contact with each other, and current flows through the electrodes at both ends of the transparent conductive film. The touched position is detected by measuring the voltage division ratio due to the resistance.

  In the process of manufacturing the touch panel sensor, the wiring such as the lead wiring for connecting the transparent conductive film and the control circuit and the metal wiring for connecting the transparent conductive film is generally conductive paste such as silver paste or conductive ink. Is formed by printing with an inkjet or other printing method. However, wiring made of pure silver or a silver alloy has poor adhesion to glass, resin, or the like, and also has a problem that the glossiness decreases due to aggregation on the substrate and the color of the display portion decreases. Therefore, high glossiness is required for the wiring, but it is difficult to say that the wiring formed using a conductive paste made of pure silver or a silver alloy has sufficient glossiness.

  On the other hand, it is also conceivable to apply pure Al having a sufficiently low electrical resistivity to the wiring material. However, when pure Al is used as the wiring material, there arises a problem that insulating aluminum oxide is formed between the transparent conductive film and the pure Al film in the touch panel sensor, and electrical conductivity cannot be ensured. Therefore, in order to prevent Al oxidation and ensure electric conductivity, a barrier metal layer made of a refractory metal such as Mo or Ti is used as a base layer by interposing between a transparent conductive film and a pure Al film. A method of using an Al—Nd alloy containing Nd having excellent heat resistance instead of pure Al has been proposed. Further, the applicant of the present invention shows an Al film containing a predetermined amount of Ni and / or Co as an Al film that exhibits low electrical resistance even when directly connected to a transparent conductive film, and that hardly increases in electrical resistance or breaks over time. A Ni / Co alloy film (single-layer wiring material) is disclosed in Patent Document 1.

JP 2009-245422 A

  An object of the present invention is to provide a touch panel sensor having high glossiness and excellent color expression.

  The touch panel sensor of the present invention capable of solving the above problems is a touch panel sensor having a transparent conductive film and a wiring connected to the transparent conductive film, wherein the wiring contains 0.05 to 5 atomic% of a rare earth element, In addition, it has a gist in that it is made of an Al alloy film having a glossiness of 800% or more.

  In a preferred embodiment of the present invention, the wiring is composed of a refractory metal film, the Al alloy film, and a refractory metal film in this order from the substrate side.

  In a preferred embodiment of the present invention, the rare earth element is one or more elements selected from the group consisting of Nd, Gd, La, Y, Ce, Pr and Dy.

  In a preferred embodiment of the present invention, the transparent conductive film is made of indium tin oxide (ITO) or indium zinc oxide (IZO).

  According to the present invention, since an Al alloy film excellent in glossiness is used as the touch panel sensor wiring, a touch panel sensor excellent in color expression can be provided.

  A feature of the present invention is that an Al alloy film containing a rare earth element (hereinafter sometimes abbreviated as an Al-rare earth element alloy film or simply an Al alloy film), which is widely used as a wiring for a touch panel sensor, is used alone. In order to increase the glossiness of the touch panel sensor in which a refractory metal film such as Mo is laminated on and below the Al alloy film, the upper limit of the rare earth element content is 5 atomic%, and the gloss The Al alloy film having a degree of 800% or more is used.

  That is, according to the examination results of the present inventors, (a) the glossiness of the wiring film has a great influence on the color of the touch panel sensor, and the crystal grain size of the Al alloy film constituting the wiring material (details) In the case where the maximum value of the constant tangent diameter called the Feret diameter is large or the density of the particle diameter is small, the glossiness of the Al alloy film decreases, and as a result, the color of the touch panel sensor is expressed. (A) In detail, the glossiness of the Al alloy film is almost determined by the size and density of the above-mentioned particle size immediately after the film formation, and even if heat treatment (annealing) is performed after the film formation, It has been found that almost no change is observed, and (c) it is effective to appropriately control the film forming conditions (preferably the temperature and Ar gas pressure during sputtering) in order to achieve high glossiness. did. Furthermore, the rare earth element content in the Al alloy film is also closely related to the glossiness of the Al alloy film, and (d) the glossiness tends to increase as the rare earth element content increases. If added in a large amount, the color of the touch panel sensor is impaired due to the problem of etching residue, so it is effective to control the upper limit to 5 atomic%. (E) Thus, the glossiness and the content of rare earth elements It is found that an Al alloy film appropriately controlled can be used alone as a material for touch panel sensor wiring, or can be used as a laminated material in which a refractory metal film such as Mo is laminated at the upper limit. The present invention has been completed.

  Thus, the glossiness of the Al-rare earth alloy film used in the present invention is 800% or more. Thereby, the glossiness of the touch panel sensor is also increased. The higher the glossiness, the better, preferably 805% or more. The upper limit of the glossiness of the Al alloy film is not specified, but the conditions for ensuring the desired glossiness (details such as the content of rare earth elements contained in the Al alloy film and the production conditions of the Al alloy film will be described later). Is about 840%. The glossiness of the Al alloy film is a value measured by the method described in Examples described later.

  The Al alloy film used in the present invention contains 0.05 to 5 atom% of rare earth elements, and the balance is Al and inevitable impurities. In the present invention, there is no feature in the composition of the Al alloy film used, and the Al alloy film containing rare earth elements has heat resistance and is known to be used as a wiring material. From the viewpoint of providing a material suitable for a touch panel sensor, an Al alloy film in which glossiness and rare earth element content are appropriately controlled has not been disclosed so far. The lower limit of the rare earth element content is determined in order to effectively exert the heat resistance effect, while the upper limit is determined in order to ensure the lower limit of glossiness defined in the present invention. It is. That is, as shown in the examples described later, the glossiness of the Al alloy film is closely related to the content of the rare earth element, and when the Al alloy film is produced under the same conditions, the higher the content of the rare earth element is, Although the glossiness of the Al alloy film also tends to increase, if the rare earth element content becomes too high, a new problem of etching residue occurs and the color is impaired, so the upper limit was set to 5 atomic%. Moreover, if it is in the said range, the electrical resistance of wiring can also be restrained low.

  As the rare earth element used in the present invention, an element obtained by adding Sc (scandium) and Y (yttrium) to a lanthanoid element (a total of 15 elements from La of atomic number 57 to Lu of atomic number 71 in the periodic table). Groups. In the present invention, these elements can be used alone or in combination of two or more. The rare earth element content is a single amount when contained alone, and when two or more kinds are contained, Total amount. Preferred rare earth elements are one or more elements selected from the group consisting of Nd, Gd, La, Y, Ce, Pr, and Dy.

  In the present invention, as the wiring material, the above-described Al alloy film may be used alone, or a material in which a refractory metal film is laminated on the upper and lower sides of the Al alloy film may be used. As described above, the refractory metal film is widely used as an underlayer of the Al alloy film in order to prevent the oxidation of Al. In the present invention, Mo, Ti, Cr, W, or an alloy thereof is used. Can do. The composition of the refractory metal films disposed above and below the Al alloy film may be the same or different at the top and bottom.

  A preferable thickness when the Al alloy film is used alone is about 150 to 600 nm. Further, when the Al alloy film is used as a laminated structure with a refractory metal film, a preferable total thickness (a refractory metal film + Al alloy film + a refractory metal film) is generally 210 to 800 nm. The preferable thickness of the Al alloy film is about 150 to 600 nm, and the preferable thickness of the refractory metal film is about 30 to 100 nm.

  In the present invention, in order to obtain an Al alloy film whose glossiness is appropriately controlled, it is preferable to appropriately control the sputtering conditions in addition to using an Al alloy film containing a predetermined rare earth element. That is, in the present invention, it is recommended to form an Al alloy film by sputtering from the viewpoint of thinning and homogenizing the alloy components in the film and controlling the amount of added elements easily. It is preferable to control the film forming temperature to about 250 ° C. or lower and the Ar gas pressure to about 15 mTorr or lower. Moreover, it is preferable to control the substrate temperature at the time of sputtering to about 250 ° C. or lower. This is because the higher the substrate temperature and the film formation temperature, the more easily the sputtered particles move on the substrate surface, which causes a coarse crystal grain size to be formed, resulting in a decrease in gloss. In addition, when the Ar gas pressure is increased, the collision frequency between the sputtered particles and the Ar gas pressure is increased, so that the energy when the sputtered particles reach the substrate is lowered and the density of the crystal grains is lowered. This is because the degree decreases.

  The glossiness of the Al alloy film (immediately after) formed under the above-mentioned preferred sputtering conditions is as high as 800% or more, and such high glossiness is maintained as it is regardless of the conditions of the subsequent heat treatment (annealing). The This is largely different from the reflectance that is strongly influenced by the state of the Al alloy film after heat treatment (such as crystal grain size and density). In the touch panel manufacturing process, it is generally exposed to a thermal history of about room temperature to about 250 ° C., but even if the annealing temperature exceeds the above range, for example, heat treatment is performed at 300 ° C., the Al alloy after the heat treatment is used. The glossiness of the film is maintained at a high level of 800% or more (see Examples described later). However, considering the heat resistance of the resin, the preferred heat treatment temperature is about 150-230 ° C.

  In the present invention, there is the greatest feature in defining the glossiness of the Al alloy film used for the wiring connected to the transparent conductive film, and other configurations are not particularly limited, and are commonly used in the field of touch panel sensors. The configuration can be adopted.

  For example, a resistive film type touch panel sensor can be manufactured as follows. That is, after a transparent conductive film is formed on a substrate, resist coating, exposure, development, and etching are sequentially performed, and then an Al alloy film (in the case of a single structure), a refractory metal film, an Al alloy film, a high melting point A metal film (in the case of a laminated structure) is sequentially formed, resist coating, exposure, development, and etching are performed to form a wiring, and then an insulating film or the like that covers the wiring is formed to form an upper electrode. be able to. Further, after forming a transparent conductive film on the substrate, photolithography is performed in the same manner as the upper electrode, and then, as in the case of the upper electrode, an Al alloy film (in the case of a single structure) or a refractory metal film, A wiring composed of an Al alloy film and a refractory metal film (in the case of a laminated structure) is formed, then an insulating film covering the wiring is formed, and a micro dot spacer is formed to form a lower electrode. it can. Then, the touch panel sensor can be manufactured by laminating the upper electrode, the lower electrode, and the tail portion separately formed.

  The said transparent conductive film is not specifically limited, As a typical example, what consists of indium tin oxide (ITO) or indium zinc oxide (IZO) can be used. In addition, as the substrate (transparent substrate), for example, glass, polycarbonate, or polyamide can be used as a commonly used substrate. For example, the substrate of the lower electrode that is a fixed electrode is made of glass. And a polycarbonate film or the like can be used for the substrate of the upper electrode that needs flexibility.

  The touch panel sensor of the present invention can also be used as a touch panel sensor such as a capacitive method or an ultrasonic surface acoustic wave method in addition to the resistive film method.

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by the following examples, and can be implemented with modifications within a range that can be adapted to the above and the following points, They are all included in the technical scope of the present invention.

Example 1
A non-alkali glass plate (thickness 0.7 mm, diameter 4 inches) is used as a substrate, and the surface thereof is subjected to DC magnetron sputtering, as shown in Table 1 below, and the type and content of rare earth elements (unit is atomic%) Then, Al alloy films (thicknesses are both about 500 nm) having different balances: Al and inevitable impurities were formed. Before film formation, the atmosphere in the chamber is once set to an ultimate vacuum of 3 × 10 ⁻⁶ Torr, and then a disk-type target having the same component composition as each Al alloy film and having a diameter of 4 inches is used. As shown in FIG. 1, the film formation temperature and the Ar gas pressure were varied. The sputtering conditions other than these are as follows. Next, the Al alloy after film formation was heat-treated at various annealing temperatures shown in Table 1 for 30 minutes in a nitrogen atmosphere. In Table 1, “-” means no heating (that is, room temperature). In addition, the composition of the formed Al alloy film was confirmed by inductively coupled plasma (ICP) mass spectrometry.
(Sputtering conditions)
Ar gas flow rate: 30sccm
・ Sputtering power: 260W
・ Substrate temperature: Room temperature

  Using the Al alloy film obtained as described above, the 60 ° specular gloss was measured based on JIS K7105-198. The glossiness is expressed as a value (%) when the glossiness of the glass surface having a refractive index of 1.567 is defined as 100.

  Furthermore, the etching residue was evaluated using the aluminum alloy film obtained by forming the film as described above. Specifically, the Al alloy film is immersed in a mixed acid etching solution (phosphoric acid: nitric acid: acetic acid: water = 70: 2: 10: 18) heated to 40 ° C., which corresponds to an etching completion time + 50% time. Time (overetching time) etching was performed. The glass surface after the etching was observed with an optical microscope (magnification 1000 times) and SEM (magnification 30,000 times), and no etching residue was observed by either observation. The etching residue was observed only by SEM observation. The result was Δ, and the case where etching residue was observed not only by SEM observation but also by optical microscope was marked by ×. In this example, “◯” or “Δ” is judged as good etching property.

  For the sample in which a pure Al film was formed instead of the Al alloy film, the glossiness and etching residue were measured in the same manner as described above.

  These results are also shown in Table 1. Table 1 shows the results of the glossiness after the heat treatment (annealing), and it has been confirmed that this value is almost the same as the glossiness immediately after film formation (before annealing).

  In Table 1, No. 4 to 18 are examples of Al alloy films containing Nd as a rare earth element. It can be seen that when the sputtering conditions and the annealing temperature are all the same, the glossiness tends to increase with an increase in the amount of Nd [for example, when the annealing temperature is room temperature (−), no. 4, 5, 6, 7, 17, 18]. Moreover, although an etching residue comes to be observed when the amount of Nd increases, it was within the acceptable range within the upper limit (5 atomic%) defined in the present invention. The glossiness is also closely related to the sputtering conditions, and the film-forming temperature or Ar gas pressure is no. 11 or No. As for the glossiness of 14, the desired glossiness (800% or more) was not obtained. Furthermore, no. Nos. 7, 15, and 16 are examples in which an Al alloy film containing 0.6 atomic% of Nd is sputtered under the same conditions and only the heat treatment temperature is changed [No. No. 7 annealing temperature = room temperature, No. 7 No. 15 annealing temperature = 150 ° C. However, regardless of the heat treatment temperature, the glossiness is almost the same (about 820%), and it was found that the glossiness is hardly affected by the heat treatment.

  From the above experimental results, in order to ensure a predetermined glossiness, the upper limit of the Nd amount is 5 atomic%, and the sputtering temperature is controlled to 250 ° C. or less and the Ar gas pressure to 15 mTorr or less. It was confirmed to be effective.

  In Table 1, No. 19 to 24 are examples using Al alloy films containing rare earth elements other than Nd. All of these were prepared by including the rare earth element content defined in the present invention and controlling the sputtering conditions within the preferable range of the present invention, so that the glossiness was controlled within the range of the present invention. Further, it has been confirmed by experiments that the same experimental results as those of Nd described above are observed when the rare earth elements other than Nd are used (not shown in Table 1).

  From these results, it is highly expected that a touch panel sensor with high glossiness can be provided by using the Al-rare earth element alloy film of the present invention.

  In contrast, no. 1-3 are examples of pure Al containing no rare earth element, and although the sputtering conditions were controlled within the preferred range of the present invention, they could not be controlled within the gloss range defined in the present invention. .

Claims (6)

In the touch panel sensor having a transparent conductive film and a wiring connected to the transparent conductive film,
The wiring is an Al alloy film containing 0.05 to 5 atomic% of a rare earth element, and has a 60 ° specular gloss specified by JIS K7105-198 and a gloss of the glass surface with a refractive index of 1.567. A touch panel sensor comprising an Al alloy film of 800% or more when the degree is 100% . The touch panel sensor according to claim 1, wherein the Al alloy film is formed by a sputtering method in which a film formation temperature during sputtering is controlled to 250 ° C. or less and an Ar gas pressure is controlled to 15 mTorr or less. The wire comprises, in order from the substrate side, and the refractory metal film, and the Al alloy film, a touch panel sensor of claim 1 or 2 in which is composed of a refractory metal film. The rare earth element, touch panel sensor according Nd, Gd, La, Y, Ce, to any one of claims 1 to 3 is one or more elements selected from the group consisting of Pr and Dy. The transparent conductive film, a touch panel sensor according to any one of claims 1-4 made of indium tin oxide (ITO) or indium zinc oxide (IZO). It is a manufacturing method of the touch panel sensor in any one of Claims 1 and 3-5,
A method of manufacturing a touch panel sensor, comprising forming an Al alloy film having a glossiness of 800% or more by controlling a film forming temperature during sputtering to 250 ° C. or less and an Ar gas pressure to 15 mTorr or less.