KR20150060536A - Touch sensor - Google Patents

Abstract

A touch sensor in accordance with an embodiment of the present invention comprises: a substrate and an electrode on the substrate, wherein the electrode includes a first diffusion barrier layer formed in contact with the substrate, an interlayer formed on the first diffusion barrier layer, and a second diffusion barrier layer formed on the interlayer. According to the present invention, the touch sensor has an effect of preventing the performance degradation due to corrosion and diffusion of the interlayer by forming the structure of the electrode with the interlayer on the first diffusion barrier layer in contact with the substrate and the second diffusion barrier layer on the interlayer.

Description

[0001]

The present invention relates to a touch sensor.

With the development of computers using digital technology, auxiliary devices of computers are being developed together. Personal computers, portable transmission devices, and other personal information processing devices use various input devices such as a keyboard and a mouse And performs text and graphics processing.

However, as the use of computers is gradually increasing due to the rapid progress of the information society, there is a problem that it is difficult to efficiently operate a product by using only a keyboard and a mouse which are currently playing an input device. Therefore, there is an increasing need for a device that is simple and less error-prone, and that allows anyone to easily input information.

In addition, the technology related to the input device is shifting beyond the level that satisfies the general functions, such as high reliability, durability, innovation, design and processing related technology, etc. In order to achieve this purpose, As a possible input device, a touch screen panel has been developed.

In addition, the market of touch screen panels (TSP) is expanding due to the emergence of smart devices. Such touch panels include electronic notebooks, liquid crystal display devices (LCDs), plasma display panels (PDP) A cathode ray tube (CRT), and the like, and is a tool used by a user to select desired information while viewing the image display apparatus.

Types of touch panel include Resistive Type, Capacitive Type, Electro-Magnetic Type, SAW (Surface Acoustic Wave Type) and Infrared Type. . These various types of touch panels are employed in electronic products in consideration of problems of signal amplification, differences in resolution, difficulty in design and processing technology, optical characteristics, electrical characteristics, mechanical characteristics, environmental characteristics, input characteristics, durability and economical efficiency Currently, the most widely used methods are resistive touch panels and capacitive touch panels.

Electrostatic metal sensors have various types and structures of metals, but ITO (In-Sn-Oxide), which is a transparent conductive metal, has become mainstream due to problems such as visibility. Recently, however, ITO indium has been a cause of cost rises due to the rise in the price of rare earth metals, and ITO also has a high temperature process, which is a disadvantage for use on heat-sensitive substrates. In addition, ITO has a fragile disadvantage that it is weak in brittle. As a result, a sensor made of metal in the form of a mesh (hereinafter referred to as "metal mesh") for use as a metal sensor for other conductive metals has been developed.

The market for metal mesh is expected to expand gradually. However, due to the high integration of devices including touch sensors, the line width of the thin film layers in these devices is further reduced, and the thin film layers are becoming more multilayered. In such an image, many problems arise due to diffusion between the metal wiring and the substrate including silicon. For this reason, attempts have been made to prevent diffusion between metal and silicon.

Currently, metal meshes are being developed as conductive metals such as aluminum (Al), silver (Ag), and copper (Cu). When copper (Cu) is used for the double metal mesh, the electric conductivity is superior to aluminum (Al), and the price is lower than silver (Ag), and it is getting popular spotlight recently.

However, there are difficulties due to the disadvantages of copper. Copper is thermodynamically unstable and easily reacts with the contact material. It is easily oxidized in an oxidizing atmosphere and has a disadvantage of poor adhesion with most insulating materials. In addition, copper is easily corroded and has a problem in improving the visibility of the metal mesh due to the red color inherent in copper. In addition, copper is known to be the best metal to diffusion into the substrate. Therefore, in order to overcome the disadvantages described above, it is common to deposit a barrier metal on the upper or lower part of the copper layer.

In particular, in the case of a window-integrated touch sensor, a metal mesh sensor is formed on a glass (SiO ₂ glass) including silicon oxide, where reactivity between copper and silicon (Si) may become a problem. Solubilites of 3d metals in silicon SJ.D. McBrayer, RMSwanson, and TWSigmon, J. Electrochem. Soc., Vol. 133, pp. 1242-1246, 1986, it can be seen that the solubility with silicon (Si) is higher than the other metals in case of copper and nickel (Ni). Furthermore, as the linewidth decreases, a high temperature is generated and the above-mentioned heat can accelerate diffusion. This diffusion causes the resistivity to increase and causes the reliability of the entire circuit as well as the electrode to deteriorate.

Also, diffusion coefficient between copper and nickel is higher than other metals. That is, even at a low temperature, diffusion may occur due to grain boundary diffusion, which may cause performance degradation. Therefore, there is a need for a diffusion preventing film capable of preventing diffusion.

In the present invention, it is confirmed that the diffusion barrier preventing diffusion of the intermediate layer is prevented by disposing a diffusion barrier layer having a melting point of 2000 ° C or more on the electrodes of the touch sensor on the upper and lower portions of the intermediate layer, ≪ / RTI >

Accordingly, one aspect of the present invention is to provide a touch sensor capable of preventing corrosion and degradation of an intermediate layer due to diffusion of a diffusion barrier film.

Another aspect of the present invention is to provide a touch sensor capable of improving operational reliability by preventing performance degradation due to diffusion.

A touch sensor (hereinafter referred to as "first invention") for achieving one aspect of the present invention includes a substrate and electrodes on the substrate; The electrode includes a first diffusion barrier film formed in contact with the substrate, an intermediate layer formed on the first diffusion barrier film, and a second diffusion barrier film formed on the intermediate layer.

In the first invention, the first and second diffusion barrier films are formed of a transition metal.

In the first invention, the first and second diffusion barrier films are formed of a metal having a melting point of 2000 ° C or higher.

The first and second diffusion barrier films may be formed of at least one of manganese (Mn), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium (Hf), tantalum (Ta), tungsten Iridium (Ir), and alloys containing at least one of them.

In the first invention, the first diffusion barrier film and the second diffusion barrier film are formed of the same material.

In the first invention, the first diffusion barrier film and the second diffusion barrier film are formed of different materials.

In the first invention, the intermediate layer is formed of any one selected from the group consisting of copper (Cu), silver (Ag), gold (Au), aluminum (Al), and an alloy containing at least one of these.

In the first invention, the substrate is a window substrate or an insulating film.

In the first invention, the substrate may be at least one selected from the group consisting of polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), polyethylene naphthalate (PEN), polyether sulfone (PES) CO), TAC (Triacetylcellulose) film, polyvinyl alcohol (PVA) film, polyimide (PI) film, polystyrene (PS), biaxially oriented PS And glass or tempered glass.

In the first invention, the line width of the electrode is formed in the range of 1 to 5 mu m.

In the first invention, the thickness of the electrode is in the range of 0.05 to 3 mu m.

In the first invention, the thickness of the first diffusion barrier film is in the range of 1 to 500 nm.

In the first invention, the thickness of the second diffusion barrier film is in the range of 1 to 500 nm.

In the first invention, the thickness of the intermediate layer is in the range of 0.03 to 2 mu m.

In the first invention, the electrode is an electrode pattern or an electrode wiring.

In the first invention, the electrode pattern is formed in a mesh shape.

A display device (hereinafter referred to as "second invention") for achieving another aspect of the present invention includes: a display panel for displaying an image; a housing for housing the display panel; And a touch sensor formed thereon.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention, by forming the intermediate layer on the first diffusion barrier film that contacts the substrate with the structure of the electrode and the second diffusion barrier film on the intermediate layer, it is possible to prevent performance degradation due to corrosion and diffusion of the intermediate layer.

In addition, since the diffusion barrier films disposed on the upper and lower sides of the intermediate layer prevent performance degradation due to diffusion, operational reliability can be improved, and more stable operation of the touch sensor can be achieved.

1 is a plan view showing a touch sensor according to an exemplary embodiment of the present invention.
2 is a cross-sectional view taken along line I-I 'of Fig.
3 is an enlarged view of the area "A" in Fig. 2.
FIG. 4 is a graph showing the temperature-dependent diffusion coefficient of a diffusion barrier metal film according to an exemplary embodiment of the present invention. FIG.
5 is an exploded perspective view showing a display device including a touch sensor according to an exemplary embodiment of the present invention.
FIG. 6 is a graph comparing changes in sheet resistance of an electrode manufactured according to an embodiment of the present invention and a comparative example.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages, and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms "one side,"" first, ""first,"" second, "and the like are used to distinguish one element from another, no. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view showing a touch sensor according to an exemplary embodiment of the present invention, FIG. 2 is a sectional view taken along line I-I 'of FIG. 1, and FIG. 3 is an enlarged view of an area labeled "A" of FIG. For ease of illustration, FIG. 2 shows a portion of the touch sensor.

1 and 2, a touch sensor 1 according to an exemplary embodiment of the present invention includes a substrate 10, a first mesh electrode 110, a first mesh electrode 110, And a second mesh electrode 120 formed in a crossed mesh shape. The first electrode wiring 150 and the second electrode wiring 160 connected to the first mesh electrode 110 and the second mesh electrode 120 may be extended. The first and second electrode wirings 150 and 160 may be formed in a bezel region which is a non-display region.

The first mesh electrode 110 and the first electrode wiring 150 may be formed integrally with the second mesh electrode 120 and the second electrode wiring 160 may be formed integrally with the mesh electrodes 110 and 120, A connection electrode may be additionally provided between the wirings 150 and 160 to connect them. Here, the first mesh electrode 110 may be an X-axis electrode, and the second mesh electrode 120 may be a Y-axis electrode.

Thus, the first and second mesh electrodes 110 and 120 are collectively referred to as electrode patterns, and the first and second electrode wires 150 and 160 are collectively referred to as electrode wires. The electrode pattern and the electrode wiring are collectively referred to as an electrode 100. The touch sensor 1 may be formed on a window substrate or on an insulating film according to a method of arranging the electrodes 100.

The substrate 10 of the present invention may be formed of a material having transparency to allow the user to recognize the supporting force for supporting the electrode 100 and the image provided by the display.

The substrate 10 may be formed of a material selected from the group consisting of polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), polyethylene naphthalate (PEN), polyether sulfone (PES), cyclic olefin polymer (TAC), polyvinyl alcohol (PVA) film, polyimide (PI) film, polystyrene (PS), biaxially oriented PS (BO resin containing K resin) Reinforced glass, and the like, but the present invention is not limited thereto.

The line width and the thickness of the electrode pattern of the electrode 100 may be different from each other. For example, the line width of the electrode pattern may be in the range of 1 to 5 mu m, and the thickness may be in the range of 0.05 to 3 mu m. The thickness of the electrode wiring may be greater than or equal to the thickness of the electrode pattern.

3, the touch sensor 1 includes an electrode 100 formed on a substrate 10, and the electrode 100 includes a first diffusion barrier film 310 formed on the substrate 10, An intermediate layer 350 on the first diffusion barrier layer 310 and a second diffusion barrier layer 320 formed on the intermediate layer 350.

The intermediate layer 350 may be formed of any one selected from the group consisting of copper (Cu), gold (Au), silver (Ag), aluminum (Al), and an alloy including at least one of these. Here, the intermediate layer 350 is illustratively illustrated in terms of cost and copper in terms of conductivity.

The first and second diffusion barrier layers 310 and 320 may be formed of a transition metal. Also, the first and second diffusion barrier films 310 and 320 can be formed by selectively selecting transition metals having a melting point of 2000 ° C or higher. For example, the first and second diffusion barrier layers 310 and 320 may be formed of at least one of manganese (Mn), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium (Hf), tantalum (W), iridium (Ir), and alloys containing at least one of them.

The first diffusion barrier layer 310 and the second diffusion barrier layer 320 may be formed of the same material. The first diffusion barrier layer 310 and the second diffusion barrier layer 320 may be formed of the same material, And may be formed of different materials.

Here, the transition metal having a low melting point has solubility as the temperature is increased, so that the copper ion can diffuse into the transition metal. Here, as the electrodes 100 are becoming highly integrated, the line width and the lamination thickness are becoming thinner. According to this trend, the electrode 100 generates more heat, and the generated heat may increase the probability of diffusion due to an increase in the solubility of the electrode materials forming the electrode 100.

Accordingly, the above-described diffusion may deteriorate the performance of the electrode 100 and deteriorate the reliability of the touch sensor 1. Therefore, it is possible to prevent diffusion by using a metal having a strong heat resistance as the diffusion barrier films 310 and 320.

As described above, the intermediate layer 350 is interposed between the first and second diffusion barrier films 310 and 320 having a melting point of 2000 ° C or higher, so that the copper ions in the intermediate layer 350 can be prevented from diffusing into the contact material.

Therefore, the first and second diffusion barrier layers 310 and 320 may be formed to have a predetermined thickness in order to prevent diffusion of copper ions in the intermediate layer 350. For example, the first diffusion barrier layer 310 may have a thickness ranging from 1 to 500 nm. Also, the thickness of the second diffusion barrier layer 320 may be in the range of 1 to 500 nm. The thickness of the intermediate layer 350 interposed between the first diffusion barrier layer 310 and the second diffusion barrier layer 320 may be in the range of 0.03 to 2 μm. Here, when the thickness of the intermediate layer is 0.03 탆 or less, the crystallinity is deteriorated and the metal resistivity of the intermediate layer becomes high, and a thickness of 2 탆 or more is difficult to be formed by a deposition process by a general sputtering.

Diffusion between metal layers can be divided into surface diffusion, grain boundary diffusion, and bulk diffusion. The type of diffusion is not limited to any particular one but is most likely to occur at the interface between the dissimilar metals and may then be diffused through grain boundaries.

In addition, there is a diffusivity that indicates the degree of diffusion of each metal, and there is a large difference in value depending on the type of metal.

The transfer of the above material can be expressed as in Fick's law,

Where D is the diffusion coefficient, dc is the concentration change, and dx is the position change.

Thus, the degree of diffusion is proportional to D, and the lower the diffusion coefficient, the lower the probability of occurrence of diffusion.

FIG. 4 is a graph showing the temperature-dependent diffusion coefficient of a diffusion barrier metal film according to an exemplary embodiment of the present invention. FIG. To avoid redundant description, a description will be made with reference to Figs. 1 to 3.

First, the diffusion coefficient can be expressed by the Arrhenius equation.

Where D is the reaction rate constant, T is the absolute temperature, R is the gas constant, D ₀ is the frequency coefficient or frequency factor, and Ea is the activation energy. Where the unit of D ₀ is equal to the rate constant unit.

Referring to FIG. 4, although a reaction occurs due to a collision between molecules of a bonding metal, that is, between molecules, only a collision with energy of a minimum value Ea among molecules can cause a reaction. The ratio of the number of impacts with energy above Ea is expressed by exp (-Ea / RT) approximately by the Boltzmann distribution. That is, when the logarithm of the reaction rate is plotted against the reciprocal of the absolute temperature, it becomes a straight line, and the activation energy Ea and the frequency factor D ₀ can be obtained from the slope and the intercept of this straight line.

Therefore, the lower the D ₀ value inherent to the material, the lower the D value. That is, the higher the melting point, the higher the Ea value and the less diffusing occurs.

By using a transition metal having a melting point of 2000 ° C or higher at which the diffusion barrier films 310 and 320 melt above and below the intermediate layer 350 formed of copper, the performance of the electrode 100 due to diffusion can be prevented .

5 is an exploded perspective view showing a display device including a touch sensor according to an exemplary embodiment of the present invention. Here, the display device including the touch sensor 1 will be described with reference to Figs. 1 to 4 in order to avoid redundant explanations.

5, a display device 5 according to an exemplary embodiment of the present invention includes a display panel 550, a housing 570 housing the display panel 550, And a touch sensor 1 disposed therein. Wherein the touch sensor 1 comprises an electrode 100 and the electrode 100 comprises first and second diffusion barrier layers 310 and 320 and between the first and second diffusion barrier layers 310 and 320 And an intermediate layer 350 interposed in the intermediate layer 350.

As an exemplary embodiment of the present invention, the display device 5 includes various information providing devices such as a television, a navigation system, a computer monitor, a game machine, and a mobile phone. The mobile phone is illustratively shown here for ease of explanation.

The display panel 5 can display an image. The display panel 5 is not particularly limited and includes, for example, an organic light emitting display panel, a liquid crystal display panel, a plasma display panel, A display panel, an electrophoretic display panel, and an electrowetting display panel.

The housing 570 can house the display panel 550. Although the housing including one member is illustrated as an example in the drawing, the housing 570 may be formed by combining two or more members. In addition, the housing 570 can further contain a circuit board on which a plurality of active elements (not shown) and / or a plurality of passive elements (not shown) are mounted in addition to the display panel 550. Depending on the type of the display device 5, a power source (not shown) such as a battery may be further housed.

The touch sensor 1 is disposed on the display panel 550 and may be coupled to the housing 570 to configure the outer surface of the display device 1 together with the housing 570. At this time, the display panel 550 may be coupled to the touch sensor 1.

The touch sensor 1 includes a display area in which an image generated in the display panel 550 is displayed on a plane, and a non-display area adjacent to at least a part of the display area. The non-display area may be formed at the edge of the display area.

The touch sensor 1 can display an image displayed on the display device 5 and input a command through a touch. At this time, the command is transmitted to the control unit through the touch, and the transfer signal is transmitted through the electrode 100 of the touch sensor 1. At this time, the performance of the electrode 100 must be excellent in order to transmit the transmission signal.

Since the copper used as the electrode 100 has high solubility, copper ions can be diffused into the bonding metals to which the silicon ions of the bonding substrate 10 are bonded. The diffusion of copper ions causes the performance of the electrode 100 to deteriorate, which may result in deterioration of the performance of the display device 5.

However, the display device 5 including the touch sensor 1 according to the exemplary embodiment of the present invention has the first and second diffusion barrier films 310 and 320 and the first and second diffusion barrier films 310 and 320, The diffusion of copper ions can be prevented by forming the intermediate layer 350 formed of copper.

Accordingly, corrosion of the electrode 100 and deterioration of the performance of the electrode 100 can be prevented by preventing the diffusion of copper ions, thereby making it possible to operate the touch sensor 1 more stably.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Example

A Ta layer was deposited to a thickness of 20 nm on a PET film having a thickness of 100 mu m by DC pulsed sputtering, and then a Cu layer as an intermediate layer was deposited to a thickness of 100 nm on the Ta layer, A Ta layer was deposited to a thickness of 60 nm to prepare a sample.

Comparative Example

A Ni layer was deposited to a thickness of 20 nm on a PET film having a thickness of 100 mu m using DC pulsed sputtering, a Cu layer as an intermediate layer was deposited on the Ni layer to a thickness of 100 nm, Ni layer was deposited to a thickness of 60 nm to prepare a sample.

The samples prepared through the above Examples and Comparative Examples were measured for initial sheet resistance using a 4-point probe, placed in a chamber, and after one week under environmental reliability conditions of 85 ° C and 85% humidity, The change in sheet resistance was measured, and the results are shown in Table 1 below.

Initial sheet resistance (Moh / ㅁ) 1st floor sheet resistance (Moh / ㅁ) The sample of the example (Ta / Cu / Ta) 301.5333 290.8 The comparative sample (Ni / Cu / Ni) 312.3333 347.6

Referring to FIG. 6, which is a graph comparing the sheet resistance changes of the electrodes manufactured according to Table 1 and the Examples and Comparative Examples, changes in sheet resistance under environmental reliability conditions of 85 ° C. and 85% In the case of the Cu / Ni sample, the rate of change in sheet resistance was increased by about 11%, because the Ni layer could not effectively prevent diffusion of Cu ions. On the other hand, in the case of Ta / Cu / Ta sample, the first-order sheet resistance decreases rather than the initial sheet resistance. This is because the Ta layer completely prevents the diffusion of Cu ions and prevents the diffusion of Cu ions. In addition, under the environmental reliability condition of 85 ° C and 85% humidity, Cu crystals become larger and grain boundaries are reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It will be apparent that modifications and improvements can be made by those skilled in the art.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: touch sensor 5: display device
10: substrate 100: electrode
110: first mesh electrode 120: mesh electrode
150: first electrode wiring 160: second electrode wiring
310: first diffusion barrier film 320: second diffusion barrier film
350: intermediate layer 550: display device
570: housing

Claims (17)

Board; And
An electrode on the substrate; / RTI >
The electrode
A first diffusion barrier film formed in contact with the substrate,
An intermediate layer formed on the first diffusion barrier film,
And a second diffusion barrier film formed on the intermediate layer.
The method according to claim 1,
Wherein the first and second diffusion barrier films are formed of a transition metal.
The method according to claim 1,
Wherein the first and second diffusion barrier layers are formed of a metal having a melting point of 2000 ° C or higher.
The method according to claim 1,
The first and second diffusion barrier films may be formed of at least one of manganese (Mn), niobium (Nb), molybdenum (Mo), ruthenium (Ru), hafnium (Hf), tantalum (Ta), tungsten (W), iridium And an alloy including at least one of these.
The method according to claim 1,
Wherein the first diffusion barrier film and the second diffusion barrier film are formed of the same material.
The method according to claim 1,
Wherein the first diffusion barrier film and the second diffusion barrier film are formed of different materials.
The method according to claim 1,
Wherein the intermediate layer is formed of any one selected from the group consisting of copper (Cu), silver (Ag), gold (Au), aluminum (Al), and an alloy containing at least one of the foregoing.
The method according to claim 1,
Wherein the substrate is a window substrate or an insulating film.
The method according to claim 1,
The substrate may be formed of at least one selected from the group consisting of polyethylene terephthalate (PET), polycarbonate (PC), polymethylmethacrylate (PMMA), polyethylene naphthalate (PEN), polyether sulfone (PES), cyclic olefin polymer (COC), triacetylcellulose ) Film, a polyvinyl alcohol (PVA) film, a polyimide (PI) film, polystyrene (PS), biaxially oriented PS (BO resin containing K resin) A touch sensor formed of any one selected from the group consisting of:
The method according to claim 1,
Wherein the line width of the electrode is in the range of 1 to 5 mu m.
The method according to claim 1,
Wherein the thickness of the electrode is in the range of 0.05 to 3 mu m.
The method according to claim 1,
Wherein the thickness of the first diffusion barrier film is in the range of 1 to 500 nm.
The method according to claim 1,
Wherein the second diffusion barrier film has a thickness ranging from 1 to 500 nm.
The method according to claim 1,
Wherein the thickness of the intermediate layer is in the range of 0.03 to 2 mu m.
The method according to claim 1,
Wherein the electrode is an electrode pattern or an electrode wiring.
16. The method of claim 15,
Wherein the electrode pattern is formed in a mesh shape.
A display panel for displaying an image;
A housing for housing the display panel; And
A touch sensor disposed on the display panel and formed according to claim 1; .

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