TWI399449B - Method of fabricating transparent conductive film - Google Patents

Description

Transparent conductive film manufacturing method

The present invention relates to a method of fabricating a conductive film, and more particularly to a method of fabricating a transparent conductive film.

With the gradual maturity of semiconductor technology, transparent conductive films have been widely used in electronic devices in various fields. For example, a pixel electrode for maintaining a display voltage in a liquid crystal display panel, a counter electrode, and a sensing electrode in a touch panel are all fields in which a transparent conductive film is applied. Most of the material of the transparent conductive film is composed of a metal oxide of indium tin or indium zinc. Metal oxides of this type can have both light penetrability and electrical conductivity at a certain optical thickness.

The following description will be made by taking a touch panel as an example. FIG. 1 is a schematic diagram of a touch panel. Referring to FIG. 1 , the touch panel 100 is composed of a carrier substrate 102 , a first transparent conductive film 104 , a second transparent conductive film 106 , and a plurality of spacers 108 . The first transparent conductive film 104 is disposed on the hard carrier substrate 102, and the spacers 108 and the second transparent conductive film 106 are sequentially disposed thereon. The first transparent conductive film 104 and the second transparent conductive film 106 are generally composed of a PET film (polyethylene terephthalate film, PET film) coated with a transparent conductive film.

The pressing action of the user causes the second transparent conductive film 106 to touch the first transparent conductive film 104 to generate a corresponding touch signal. because Therefore, the carrier substrate 102 must have certain mechanical strength and physical properties to prevent the touch action of the touch panel 100 from generating a wrong touch signal or a signal error caused by human error. For example, the carrier substrate 102 is often a glass substrate or a rigid plastic substrate such as polycarbonate.

Since the glass substrate can withstand a relatively high temperature, when the glass is used as the carrier substrate 102, the first transparent conductive film 104 is, for example, a transparent conductive film directly plated on the glass substrate. However, the texture of the glass substrate is liable to be broken, and the touch panel 100 is also increased in weight.

Hard plastic substrates such as polycarbonate are light in weight and easy to mold, but cannot withstand the high temperatures of the sputtering process. Therefore, when a polycarbonate (PC) substrate is used as the carrier substrate 102, the first transparent conductive film 104 must be a PET film coated with a transparent conductive film. Moreover, the PET film coated with the transparent conductive film needs to be additionally subjected to a film process to adhere the PET film to the rigid plastic substrate. Therefore, the bonding process of the PET film and the substrate causes an increase in production cost and a decrease in yield due to the filming process. As a result, not only will the cost of production increase, but the thickness of the touch panel 100 itself will also increase, resulting in a lower transmittance of visible light.

The present invention provides a method for fabricating a transparent conductive film to solve the problem that a rigid plastic substrate cannot be applied to a conventional transparent conductive film sputtering process.

The present invention provides a method of fabricating a transparent conductive film comprising the steps described below. First, a reaction chamber is provided, wherein the reaction chamber has One less target and at least one heating device. Then, a plasma is generated in the reaction chamber, and the plasma is located above the target. Then, the plasma is heated from a standby temperature to a working temperature by using a heating device, and a hard plastic substrate is passed over the plasma at a specific rate, wherein the target particles after being struck by the plasma are deposited by sputtering. A transparent conductive film is formed on the rigid plastic substrate.

In an embodiment of the invention, the standby temperature is from 0 ° C to 200 ° C.

In one embodiment of the invention, the above operating temperature is from 0 °C to 450 °C.

In an embodiment of the present invention, before the hard plastic substrate passes over the plasma, the manufacturing method further includes performing a pre-treatment process on the rigid plastic substrate. The pretreatment process is, for example, coating a layer of material having a thickness of several tens of nanometers on a rigid plastic substrate, the composition of which includes chromium, ruthenium, osmium oxide or a combination thereof.

In an embodiment of the invention, before the hard plastic substrate passes over the plasma, the manufacturing method further comprises performing a pre-heat treatment on the rigid plastic substrate. For example, the preheat treatment process temperature is from 70 ° C to 130 ° C.

In an embodiment of the invention, the hard plastic substrate is made of polycarbonate (PC).

In an embodiment of the invention, the material of the target material comprises a metal oxide of indium tin or indium zinc which is composed of different proportions.

In an embodiment of the invention, the higher the operating temperature, the faster the specific rate.

The invention passes through a reaction chamber when the rigid plastic substrate passes through the reaction chamber. Instant heating, this momentary high temperature environment will help to improve the conductivity and physical properties of the transparent conductive film. In addition, the time during which the rigid plastic substrate passes through the reaction chamber may also vary with the temperature of the reaction chamber to avoid deformation of the plastic substrate. In this way, the present invention provides a method of fabricating a transparent conductive film on a rigid plastic substrate.

The above and other objects, features, and advantages of the present invention will become more apparent from the description of the appended claims.

Since the plastic substrate itself has a low temperature range, the transparent conductive film cannot be directly applied to the plastic substrate by conventional sputtering. Therefore, the application range of the plastic substrate is greatly limited. For this reason, the present invention proposes a method for producing a transparent conductive film which can directly form a transparent conductive film on a rigid plastic substrate and which has a good conductive property. In addition, such a manufacturing method does not cause the rigid plastic substrate to be deformed or damaged by heat.

2 is a top view showing a manufacturing process of a transparent conductive film according to an embodiment of the present invention, and FIG. 3 is a side view showing a manufacturing process of a transparent conductive film according to an embodiment of the present invention. Referring to FIG. 2 and FIG. 3 simultaneously, the method for fabricating the transparent conductive film of the present embodiment includes the steps described below. First, a reaction chamber 200 is provided in which the reaction chamber 200 has at least one target 210 and at least one heating device 220. The material of the target 210 may include metal oxides of indium tin or indium zinc in different proportions, of course, the material of the target 210 is also Other conductive materials may be selected, and the invention is not limited thereto.

In one embodiment, the composition ratio of indium tin metal in the target 210 to the composition ratio of the indium zinc metal may be adjusted according to different processes or product requirements. For example, the ratio of the tin metal component in the target 210 may be 2 to 15%. However, the above composition ratios are for illustrative purposes only and are not intended to limit the scope of the invention.

Then, a plasma 230 is generated in the reaction chamber 200, and the plasma 230 is generated, for example, above the target 210. The plasma 230 is composed of, for example, particles of a charged gas molecule, a gas atom, an electron, or the like. The particles in the plasma 230 have a certain amount of energy that can strike the surface of the target 210 such that particles on the surface of the target 210 are detached from the body of the target 210 by bombardment of the plasma 230. These particles detached from the target 210 will be deposited on the surface of another material by sputtering to achieve the effect of sputtering. In the present embodiment, after the plasma 230 is generated in the reaction chamber 200, the plasma 230 is first maintained in a standby state. At this time, the standby temperature in the reaction chamber 200 is, for example, about 0 ° C to 200 ° C.

Next, the plasma 230 is heated from the standby temperature to an operating temperature by the heating device 220, and a hard plastic substrate 300 is passed over the plasma 230. At this time, the plasma 230 strikes the target 210 to detach the particles on the surface of the target 210 and deposits on a rigid plastic substrate 300 by sputtering to form a transparent conductive film 310. In this step, the reaction chamber 200 will be heated to an operating temperature of about 0 ° C to 450 ° C.

In the present embodiment, the heating device 220 primarily heats the plasma 230 such that the plasma 230 and the particles struck from the target 210 have higher energy at the same time. In this way, it will be beneficial for the target 210 to be struck. The particles are capable of forming a transparent conductive film 310 having better mechanical strength and physical properties on the rigid plastic substrate 300.

In general, the transparent conductive film 310 has preferable physical properties such as a low conductive resistance. Therefore, in the present embodiment, the particles struck by the target 210 obtain higher energy by the action of the instantaneous heating to form the transparent conductive film 310 having better conductivity. In addition, in this embodiment, the rigid plastic substrate 300 is passed over the plasma 230 at a specific rate V instead of being fixedly placed above the plasma 230, so that the rigid plastic substrate 300 is not deformed by excessive heat. In other words, in this embodiment, a transparent conductive film 310 can be formed on the rigid plastic substrate 300 before the rigid plastic substrate 300 is deformed.

It is worth mentioning that the specific rate V of the rigid plastic substrate 300 through the plasma 230 is actually related to the control of the operating temperature conditions of the environment. As the operating temperature is higher, the specific rate V of the rigid plastic substrate 300 through the plasma 230 needs to increase. Conversely, the hard plastic substrate 300 can pass through a specific rate V above the plasma 230 to be relatively slow. The rigid plastic substrate 300 can be disposed, for example, on a vehicle to change the specific rate V of the rigid plastic substrate 300 through the plasma 230 by the speed of the console.

In the present embodiment, in order to monitor the temperature change in the reaction chamber 200, for example, a temperature sensing device 240 may be disposed in the reaction chamber 200. The temperature sensing device 240 can be a thermocouple rod that projects into the interior of the reaction chamber 200 to sense temperature changes in the plasma 230. Of course, the temperature sensing device 240 may also be other temperature sensing devices, and the present invention is not limited thereto. In addition, this embodiment is an example in which the operating temperature is set at 0 ° C to 450 ° C, but in other cases. The operating temperature in the example can also vary with different needs. In summary, the higher the ambient operating temperature, the higher the energy obtained by the plasma 230. The conductivity of the transparent conductive film 310 will also be significantly improved, but it is limited by the low heat resistance of the rigid plastic substrate 300 itself. Therefore, in the manufacturing method of the embodiment, the operating temperature of the environment must be controlled within an appropriate range, and it is not suitable for unrestricted temperature rise.

In order to improve the adhesion between the transparent conductive film 310 and the rigid plastic substrate 300, the present embodiment may perform a pre-treatment process on the rigid plastic substrate 300 before performing the above-described process steps. The process includes forming a pretreatment layer (not shown) on the surface of the rigid plastic substrate 300. The material of the pretreatment layer (not shown) includes chromium, ruthenium, iridium oxide or a combination thereof. Of course, the material of the pretreatment layer (not shown) is not limited thereto, and other materials may be selected as the pretreatment layer (not shown) in other process steps.

In addition, before the rigid plastic substrate 300 passes through the reaction chamber 200, the present embodiment can further perform a pre-heat treatment on the rigid plastic substrate 300, and the process temperature of the pre-heat treatment is, for example, 70 ° C to 130 ° C. When the pre-heat treated rigid plastic substrate 300 passes over the plasma 230, the particle temperature of the target 210 that is struck is closer to the temperature of the rigid plastic substrate 300. As a result, not only the mechanical strength of the transparent conductive film 310 can be increased, but also the physical properties of the overall transparent conductive film 310 can be significantly assisted. It is to be noted that the material of the rigid plastic substrate 300 of the present embodiment is, for example, polycarbonate. Therefore, the process temperature of the pre-heat treatment is, for example, not more than 130 ° C to prevent deformation of the rigid plastic substrate 300. In addition, the material of the rigid plastic substrate 300 may also be polymethacrylate (PMMA) or polyparaphenylene. Materials such as ethyl dicarboxylate (PET), triacetate (TAC), and polyamidamine (PI). If the hard plastic substrate 300 is made of other materials, the process temperature of the preheat treatment may be changed.

Furthermore, before the hard plastic substrate 300 is processed, most of the pre-baking process is performed on the substrate, and then placed in a vacuum chamber to help effectively remove the surface moisture. . In addition, before the hard plastic substrate 300 is subjected to coating processing, an activation process may be performed on the surface thereof, for example, a plasma process is performed to activate the surface of the rigid plastic substrate 300. Of course, the manufacturing method of the present invention is not limited to the above-described pre-processing steps.

In general, the lower substrate of the touch panel is generally subjected to a filming process in which a plastic film (for example, a PET film) coated with a conductive film is attached to the rigid plastic substrate 300. . Possible problems with this filming process: In addition to the problem that the conductive film is easily peeled off, the yield of the product may also decrease during the filming process. Compared with the conventional design, the touch panel of the present invention can not only remove the additional film process, but also greatly improve the process yield, and at the same time, the rigid plastic substrate 300 forming the transparent conductive film 310 of the embodiment is applied. Not only can the touch panel have better transmittance, but also the easy processing and light weight characteristics of the rigid plastic substrate 300 can help to compensate for the shortcomings of the glass substrate.

The transparent conductive film 310 obtained by the present embodiment has good physical properties, and particularly the conductive stability is also remarkably improved. According to the manufacturing method of the present embodiment, the degree of crystallization of the ITO film formed on the PC substrate can be comparable to the degree of crystallization of the ITO film formed on the glass substrate, and Achieve good characteristics. 4 is a view showing a comparison of crystallinity of a transparent conductive film according to an embodiment of the present invention. Referring to FIG. 4, a diffraction curve 410 represents an X-ray crystal diffraction pattern of an ITO film formed on a PC substrate according to the fabrication method of the present embodiment, and a diffraction curve 420 represents a conventional method for forming on a glass substrate. X-ray crystal diffraction pattern of ITO film. In general, since the temperature resistance of the glass substrate is good, the degree of crystallization of the ITO film on the glass is remarkably better than that of the plastic material. Therefore, the peak of the ITO film at the diffraction angle of each feature is remarkable as shown by the diffraction curve 420. As can be seen from Fig. 4, the ITO film produced by the manufacturing method of the present embodiment is also quite remarkable at the peak of the diffraction angle of each feature. Therefore, FIG. 4 can further explain that the production method of the present embodiment can produce an ITO film having a good degree of crystallinity.

In addition, the transparent conductive film 310 can also achieve high reliability in terms of temperature resistance and weather resistance. For example, the general touch panel requires that the resistance change rate of the transparent conductive film 310 can be less than 25% after 72 to 240 hours at 80 ° C or 60 ° C and 90% relative humidity. Therefore, the rigid plastic substrate 300 having the transparent conductive film 310 formed by using the embodiment will also have better signal transmission quality on the touch panel. Of course, the rigid plastic substrate 300 on which the transparent conductive film 310 is formed in the embodiment is not limited to being applied to the touch panel.

FIG. 5 shows a touch panel according to an embodiment of the present invention. Referring to FIG. 5 , the touch panel 500 includes a rigid plastic substrate 300 , a transparent conductive film 310 , a transparent conductive film 510 , and a plurality of spacers 520 . The transparent conductive film 310 is formed, for example, by the above-described process, and is directly disposed on the rigid plastic substrate 300. The transparent conductive film 510 is disposed on the rigid plastic substrate 300 and transparent Above the conductive film 310, the spacer 520 is located between the transparent conductive film 510 and the transparent conductive film 310. The transparent conductive film 510 is composed of a PET film coated with a conductive film.

In the present embodiment, the transparent conductive film 310 is a conductive oxide film formed directly on the rigid plastic substrate 300, instead of being formed on the PET film and then attached to the rigid plastic substrate 300. Therefore, the thickness of the touch panel 500 is reduced by at least one film thickness of the PET film compared to the conventional design. In addition, in the process of the touch panel 500, it is not necessary to attach the PET film to the rigid plastic substrate 300, so that no additional problems are caused by the coating process. In other words, the process yield of the touch panel 500 can be further improved.

In summary, when the rigid plastic substrate is subjected to a process of instantaneously heating the reaction chamber while passing through the target, a transparent conductive film having better physical properties and mechanical strength can be obtained. At the same time, the control of the traveling speed of the trolley can also prevent the rigid plastic substrate from being deformed due to overheating of the reaction chamber. Therefore, the method for fabricating the transparent conductive film of the present invention can form a transparent conductive film having good physical properties, and can also prevent deformation or damage of the rigid plastic substrate.

Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100, 500‧‧‧ touch panel

102‧‧‧Loading substrate

104‧‧‧First transparent conductive film

106‧‧‧Second transparent conductive film

108, 520‧‧‧ spacers

200‧‧‧reaction chamber

210‧‧‧ Target

220‧‧‧ heating device

230‧‧‧ Plasma

240‧‧‧Temperature sensing device

300‧‧‧hard plastic substrate

310‧‧‧Transparent conductive film

410, 420‧‧‧ diffraction curve

510‧‧‧Transparent conductive film

V‧‧‧Specific rate

FIG. 1 is a schematic diagram of a touch panel.

2 is a top view showing a manufacturing process of a transparent conductive film according to an embodiment of the present invention.

3 is a side view showing a manufacturing process of a transparent conductive film according to an embodiment of the present invention.

4 is a view showing a comparison of crystallinity of a transparent conductive film according to an embodiment of the present invention.

FIG. 5 is a touch panel according to an embodiment of the present invention.

200‧‧‧reaction chamber

210‧‧‧ Target

220‧‧‧ heating device

230‧‧‧ Plasma

240‧‧‧Temperature sensing device

300‧‧‧hard plastic substrate

310‧‧‧Transparent conductive film

V‧‧‧Specific rate

Claims (11)

A method for fabricating a transparent conductive film, comprising: providing a reaction chamber having at least one target and at least one heating device; generating a plasma in the reaction chamber, the plasma being located above the target; And using the heating device to raise the plasma from a standby temperature to an operating temperature, and passing a hard plastic substrate through the plasma at a specific rate, wherein the target particles after being struck by the plasma will be splashed The radiation method is deposited on the rigid plastic substrate to form a transparent conductive film. The method for producing a conductive film according to claim 1, wherein the standby temperature is 0 ° C to 200 ° C. The method for producing a conductive film according to claim 1, wherein the operating temperature is from 0 ° C to 450 ° C. The method for fabricating a conductive film according to claim 1, wherein before the hard plastic substrate passes over the plasma, a pretreatment process is performed on the hard plastic substrate. The method for fabricating a conductive film according to claim 4, wherein the pretreatment process comprises forming a surface pretreatment layer on a surface of the rigid plastic substrate. The method for fabricating a conductive film according to claim 5, wherein the material of the surface pretreatment layer comprises chromium, antimony, cerium oxide or a combination thereof. The manufacturer of the conductive film as described in claim 1 The method further comprises: pre-heat treating the hard plastic substrate before the hard plastic substrate passes over the plasma. The method for producing a conductive film according to claim 7, wherein the preheat treatment has a process temperature of 70 ° C to 130 ° C. The method for producing a conductive film according to claim 1, wherein the hard plastic substrate is made of polycarbonate, polymethacrylate, polyethylene terephthalate, triacetate or polyarylene. amine. The method for fabricating a conductive film according to claim 1, wherein the material of the target comprises a metal oxide composed of indium tin or indium zinc in different proportions. The method for fabricating a conductive film according to claim 1, wherein the higher the operating temperature, the faster the specific rate, and the lower the operating temperature, the slower the specific rate.