A manufacturing method of a transparent circuit layer including a low-resistance circuit

Abstract

The present invention relates to a method for manufacturing a transparent circuit layer including low-resistance lines, comprising the following steps: (1) forming a low-resistance copper film on the surface of a transparent substrate, and then patterning the low-resistance copper film to form a copper circuit; (3) depositing a transparent conductive film covering the low-resistance copper film on the surface of the transparent substrate; characterized in that: after the step (1), step (2) is also carried out, by slightly oxidizing the surface of the copper circuit, a thin oxide layer is formed on the surface of the copper circuit; in the step (3), the formed transparent conductive film is a transparent conductive film with at least an oxygen-deficient state at the bottom layer; after the step (3), step (4) is also carried out, so that the bottom layer of the transparent conductive film reacts with the thin oxide layer, and the bottom layer of the transparent conductive film and the thin oxide layer are tightly bonded together. The present invention can improve the adhesion of the transparent conductive film above the copper line and ensure the reliability of conduction between the copper circuit and the transparent conductive film.

Description

Technical Field

[0001] The present invention relates to the technical field of transparent circuit boards, and particularly relates to a manufacturing method of a transparent circuit layer including a low-resistance circuit. Background Art

[0002] Generally, a transparent glass or plastic film is used as a transparent substrate for a transparent circuit board, and a transparent circuit layer is provided on the transparent substrate. The transparent circuit layer generally includes a transparent electrode and a transparent circuit, which are generally formed by patterning a transparent conductive film plated on the transparent substrate.

[0003] When such a transparent circuit board is applied to high-power products (such as a transparent electrothermal screen or an ultrasonic transducer screen), in order to enable the transparent circuit layer to conduct a large current, a low-resistance circuit is often required to be disposed under the transparent circuit layer. Such a low-resistance circuit generally selects a copper circuit formed by patterning a low-resistance copper film. However, in terms of materials, copper belongs to a metal crystal, while a transparent conductive oxide is generally an ionic crystal. Therefore, when an oxide transparent conductive thin film adheres to the copper circuit, the contact surface between the two is difficult to fuse, resulting in relatively low adhesion. Thus, there is often a problem of poor electrical contact due to film layer peeling.

[0004] Although someone has proposed a method of roughening the surface of the copper circuit to improve the adhesion of the transparent conductive film to solve the above problems, however, due to the low thickness of the copper circuit, this roughening method is difficult to effectively implement. Therefore, this method is difficult to effectively solve the problem of insufficient adhesion of the transparent conductive film on the copper circuit. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a manufacturing method of a transparent circuit layer including a low-resistance circuit, which can improve the adhesion of the transparent conductive film on the copper circuit and ensure the reliability of conduction between the copper circuit and the transparent conductive film. The adopted technical solution is as follows:

[0006] A manufacturing method of a transparent circuit layer including a low-resistance circuit includes the following steps: (1) forming a low-resistance copper film on the surface of a transparent substrate, and then patterning the low-resistance copper film to form a copper circuit; (3) depositing a transparent conductive film covering the low-resistance copper film on the surface of the transparent substrate; characterized in that: after the step (1), step (2) is further performed, by slightly oxidizing the surface of the copper circuit, a thin oxide layer is formed on the surface of the copper circuit; in the step (3), the formed transparent conductive film is a transparent conductive film with at least an oxygen-deficient state at the bottom layer; after the step (3), step (4) is further performed, so that the bottom layer of the transparent conductive film reacts with the thin oxide layer, and the bottom layer of the transparent conductive film and the thin oxide layer are tightly bonded together.

[0007] As a specific solution of the present invention, in the step (1), a low-resistance copper film is first formed on the surface of the transparent substrate by using a magnetron sputtering method or an electroplating method multiple times; then, the low-resistance copper film is etched by a photolithography method to achieve patterning, thereby forming the copper circuit. Specifically, the thickness of the low-resistance copper film can reach more than 1 μm.

[0008] As a preferred solution of the present invention, in the step (2), the copper circuit is heat-treated in a low-pressure oxygen atmosphere environment to form the thin oxide layer.

[0009] As a further preferred solution of the present invention, the oxygen partial pressure of the low-pressure oxygen atmosphere is not greater than 0.1 Pa, the heat treatment temperature is controlled at 150 - 250 °C, and the heat treatment time is 10 - 30 minutes.

[0010] In the step (2), if the formed thin oxide layer is too thin, effective adhesion cannot be formed; if the formed thin oxide layer is too thick, the thin oxide layer cannot be completely reduced, and the finally remaining thin oxide layer will instead affect the conductivity between the copper circuit and the transparent conductive film. As a preferred solution of the present invention, the thickness of the thin oxide layer formed in the step (2) is 1 - 10 nm.

[0011] As a further preferred solution of the present invention, the thickness of the thin oxide layer formed in the step (2) is 2 - 5 nm.

[0012] As a preferred solution of the present invention, in the step (4), the reaction between the bottom layer of the transparent conductive film and the thin oxide layer is a redox reaction, specifically: the metal atoms of the bottom layer of the transparent conductive film are oxidized by the thin oxide layer, the thin oxide layer is reduced to metallic copper, and the oxygen atoms of the thin oxide layer migrate to the bottom layer of the transparent conductive film to form an interpenetration between the bottom layer of the transparent conductive film and the copper circuit, thereby forming a nanoscale intersolubility layer.

[0013] As a further preferred solution of the present invention, the transparent conductive film is an indium tin oxide thin film; in the step (4), some of the incompletely oxidized indium atoms in the bottom layer of the transparent conductive film migrate to the thin oxide layer. Generally, the indium tin oxide thin film is composed of indium oxide (In2O3) doped with a certain proportion (≈10% by mass) of tin oxide (SnO2).

[0014] As a still further preferred solution of the present invention, in the bottom layer of the transparent conductive film, the atomic number ratio of oxygen to indium is less than 3:2. This makes the indium tin oxide thin film present an oxygen-deficient state.

[0015] As a further preferred embodiment of the present invention, in the step (3), the indium tin oxide thin film is deposited on the transparent substrate by magnetron sputtering. Specifically, the indium tin oxide thin film can be formed by magnetron sputtering using an indium tin oxide target. During the coating process, the oxygen partial pressure in the environment is controlled to be less than 0.002 Pa, whereby an indium tin oxide thin film with an oxygen-deficient state at the bottom layer can be sputtered (the transparency of the indium tin oxide thin film can be observed by the naked eye to be less than 85%, and through XPS testing, the defect of the atomic ratio is generally 1% - 5%).

[0016] As a preferred embodiment of the present invention, in the step (4), the reaction between the bottom layer of the transparent conductive film and the thin oxide layer is caused by irradiating ultraviolet light. Since the thin oxide layer on the surface of the low-resistance copper film is more likely to absorb ultraviolet light and thus react with the thin oxide layer, by irradiating ultraviolet light, especially UVC with a frequency of 280 - 190 nm, it is easier to induce the reaction between the thin oxide layer and the oxygen-deficient bottom layer of the transparent conductive film. The oxygen atoms of the thin oxide layer migrate to the bottom layer of the transparent conductive film, and some of the incompletely oxidized indium atoms in the bottom layer of the transparent conductive film migrate to the thin oxide layer, ultimately forming an interpenetration between the bottom layer of the transparent conductive film and the copper circuit, which can improve the efficiency of the process treatment.

[0017] In order to fully oxidize the thin oxide layer, as a further preferred embodiment of the present invention, in the step (4), after irradiating ultraviolet light, the copper circuit is annealed to cause the reaction between the bottom layer of the transparent conductive film and the thin oxide layer. Thereby, the reaction between the bottom layer of the transparent conductive film and the thin oxide layer can be further promoted, and at the same time, the transparent conductive film is fully oxidized to improve its transparency (> 90%).

[0018] As a further preferred embodiment of the present invention, in the step (4), the copper circuit is annealed in an oxygen or oxygen-containing atmosphere (such as air), the annealing temperature is controlled at 150 - 250 °C, and the treatment time is 10 - 30 minutes.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] In the method for manufacturing the transparent circuit layer of the present invention, first, the surface of the copper circuit is mildly oxidized to form a thin oxide layer on the surface of the copper circuit; then, a transparent conductive film with an oxygen-deficient state at the bottom layer is deposited on the surfaces of the transparent substrate and the thin oxide layer, and the reaction between the bottom layer of the transparent conductive film and the thin oxide layer is caused by irradiating ultraviolet light and other means, so that the oxygen atoms of the thin oxide layer migrate to the bottom layer of the transparent conductive film, the thin oxide layer is reduced to metallic copper, and the metal atoms in the bottom layer of the transparent conductive film are oxidized by the thin oxide layer to form an interpenetration between the bottom layer of the transparent conductive film and the copper circuit, forming a nanoscale intersolubility layer, thereby improving the adhesion of the transparent conductive film on the copper circuit and being beneficial to ensuring the conductivity reliability between the copper circuit and the transparent conductive film. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic flow chart of a method for manufacturing a transparent circuit layer according to a preferred embodiment of the present invention. Embodiment

[0022] As Figure 1 shown, this method for manufacturing a transparent circuit layer including low-resistance lines includes the following steps:

[0023] Step (1): (1-1) A low-resistance copper film 2 with a thickness of more than 1 μm is formed on the surface of a transparent substrate 1 by using a multiple magnetron sputtering method (or electroplating method); (1-2) The low-resistance copper film 2 is etched by using a photolithography method to achieve patterning, and a copper circuit 21 is formed.

[0024] Step (2): Under a low-pressure oxygen atmosphere environment (the oxygen partial pressure of the low-pressure oxygen atmosphere is 0.05 - 0.1 Pa), the copper circuit 21 is heat-treated (the heat treatment temperature is controlled at 150 - 250 °C, and the heat treatment time is 10 - 30 minutes), so that the surface of the copper circuit 21 is mildly oxidized, and a thin oxide layer 3 with a thickness of 2 - 5 nm is formed on the surface of the copper circuit 21.

[0025] Step (3): A transparent conductive film 4 covering the low-resistance copper film 2 is deposited on the surface of the transparent substrate 1, and the transparent conductive film 4 is at least a transparent conductive film 4 with an anoxic bottom layer.

[0026] Step (4): An oxidation-reduction reaction occurs between the bottom layer of the transparent conductive film 4 and the thin oxide layer 3. The metal atoms at the bottom layer of the transparent conductive film 4 are oxidized by the thin oxide layer 3, and the thin oxide layer 3 is reduced to metallic copper. The oxygen atoms of the thin oxide layer 3 migrate to the bottom layer of the transparent conductive film 4 to form an interpenetration between the bottom layer of the transparent conductive film 4 and the copper circuit 21, forming a nanoscale intersolubility layer 5, so that the bottom layer of the transparent conductive film 4 and the thin oxide layer 3 are tightly combined together.

[0027] In this embodiment, in the step (3), an indium tin oxide thin film is deposited on the transparent substrate 1 by using a magnetron sputtering method. Specifically, an indium tin oxide target is used, and the film is formed by magnetron sputtering. During the film deposition process, the oxygen partial pressure in its environment is controlled to be less than 0.002 Pa. Thus, a transparent conductive film 4 with an anoxic bottom layer can be sputtered (the transparency of the transparent conductive film 4 can be observed by the naked eye to be less than 85%, and through XPS testing, the atomic ratio defect is generally 1% - 5%. This indium tin oxide thin film is composed of indium oxide (In2O3) doped with a certain proportion (≈10% by mass) of tin oxide (SnO2). At the bottom layer of the transparent conductive film 4, the number ratio of oxygen atoms to indium atoms is less than 3:2, so that the indium tin oxide thin film presents an anoxic state); in the step (4), some incompletely oxidized indium atoms at the bottom layer of the transparent conductive film 4 migrate to the thin oxide layer 3.

[0028] In this embodiment, in the step (4), step (4-1) causes the bottom layer of the transparent conductive film 4 to react with the thin oxide layer 3 by irradiating ultraviolet light (such as UVC with a frequency of 280-190 nm); and step (4-2) anneals the copper circuit 21 in an oxygen or oxygen-containing atmosphere (such as air) (the annealing temperature is controlled at 150-250° C. and the processing time is 10-30 minutes) so that the bottom layer of the transparent conductive film 4 reacts with the thin oxide layer 3. Since the thin oxide layer 3 on the surface of the low-resistance copper film 2 is more likely to absorb ultraviolet light and thus react with the thin oxide layer 3, irradiating ultraviolet light, especially UVC with a frequency of 280-190 nm, is more likely to induce the thin oxide layer 3 to react with the bottom layer of the oxygen-deficient transparent conductive film 4, and the oxygen atoms of the thin oxide layer 3 migrate to the bottom layer of the transparent conductive film 4, while some incompletely oxidized indium atoms of the bottom layer of the transparent conductive film 4 migrate to the thin oxide layer 3, ultimately forming an interlocking of the bottom layer of the transparent conductive film 4 and the copper circuit 21, which can improve the efficiency of the process. The copper circuit 21 is annealed in air so that the bottom layer of the transparent conductive film 4 reacts with the thin oxide layer 3, thereby further allowing the bottom layer of the transparent conductive film 4 to fully react with the thin oxide layer 3 and fully oxidizing the transparent conductive film 4 to increase its transparency (>90%).

[0029] Table 1 shows the adhesion test and comparison of three samples, Sample AA, Sample B1, and Sample B2, obtained by the various steps of the present invention, using the cross-grid test method; wherein, Sample A is a control sample, which does not adopt step (2) but directly jumps to steps (3) and (4) after copper plating in step (1); Sample B1 is prepared according to steps (1)-(3) without adopting step (4); and Sample B2 is prepared according to steps (1)-(4). From the experimental results in the table, it can be seen that Sample B2, which has undergone the above-mentioned complete steps (1)-(4), exhibits the optimal adhesion of 0 / ASTM grade, indicating that the above-mentioned method can effectively improve the adhesion of the transparent conductive film 4 on the low-resistance copper film 2.

[0030] Table 1:

[0031]

[0032] The following is a detailed introduction to the 100-grid test method:

[0033]

[0034] In addition, it should be noted that for the specific embodiments described in this specification, the names of their respective parts and the like may be different. Any equivalent or simple changes made to the structure, features, and principles described according to the inventive concept of this invention patent are included within the protection scope of this invention patent. Those skilled in the technical field to which this invention pertains can make various modifications, supplements, or use similar ways of substitution to the specific embodiments described, as long as they do not deviate from the structure of this invention or exceed the scope defined by this claims, they should all fall within the protection scope of this invention.

Claims

1. A method for manufacturing a transparent circuit layer including a low-resistance circuit, comprising the following steps: (1) forming a low-resistance copper film on the surface of a transparent substrate, and then patterning the low-resistance copper film to form a copper circuit; (3) depositing a transparent conductive film covering the low-resistance copper film on the surface of the transparent substrate; characterized in that: After the step (1), step (2) is further carried out. By mildly oxidizing the surface of the copper circuit, a thin oxide layer is formed on the surface of the copper circuit; in the step (3), the formed transparent conductive film is a transparent conductive film with at least an oxygen-deficient state at the bottom layer; after the step (3), step (4) is further carried out to cause a redox reaction between the bottom layer of the transparent conductive film and the thin oxide layer. The metal atoms at the bottom layer of the transparent conductive film are oxidized by the thin oxide layer, the thin oxide layer is reduced to metallic copper, and the oxygen atoms of the thin oxide layer migrate to the bottom layer of the transparent conductive film to form an interpenetration between the bottom layer of the transparent conductive film and the copper circuit, forming a nanoscale intersolubility layer, so that the bottom layer of the transparent conductive film and the thin oxide layer are tightly bonded together.

2. The manufacturing method of a transparent circuit layer including a low-resistance circuit according to claim 1, characterized in that: In the step (2), the copper circuit is heat-treated in a low-pressure oxygen atmosphere environment to form the thin oxide layer; wherein, the oxygen partial pressure of the low-pressure oxygen atmosphere is not greater than 0.1 Pa, the heat treatment temperature is controlled at 150-250 °C, and the heat treatment time is 10-30 minutes.

3. A method for manufacturing a transparent circuit layer including a low-resistance line according to claim 1, characterized in that: The thickness of the thin oxide layer formed in the step (2) is 1-10 nm.

4. The manufacturing method of a transparent circuit layer including a low-resistance circuit according to claim 3, wherein: The thickness of the thin oxide layer formed in the step (2) is 2-5 nm.

5. A method for manufacturing a transparent circuit layer including a low-resistance line according to claim 1, characterized in that: The transparent conductive film is an indium tin oxide thin film. In the step (3), the indium tin oxide thin film is deposited on the transparent substrate by magnetron sputtering; in the step (4), some of the incompletely oxidized indium atoms at the bottom layer of the transparent conductive film migrate to the thin oxide layer.

6. The manufacturing method of a transparent circuit layer including a low-resistance circuit according to claim 5, characterized in that: At the bottom layer of the transparent conductive film, the atomic number ratio of oxygen to indium is less than 3:

2.

7. A method for manufacturing a transparent circuit layer including a low-resistance line according to any one of claims 1-4, characterized in that: In the step (4), the bottom layer of the transparent conductive film and the thin oxide layer are caused to react by irradiating ultraviolet light.

8. A method for manufacturing a transparent circuit layer including a low-resistance line according to claim 7, characterized in that: In the step (4), after irradiating ultraviolet light, the bottom layer of the transparent conductive film and the thin oxide layer are caused to react by annealing the copper circuit.

9. A method for manufacturing a transparent circuit layer including a low-resistance line according to claim 8, characterized in that: In the step (4), the copper circuit is annealed in an oxygen or oxygen-containing atmosphere environment, the annealing temperature is controlled at 150-250 °C, and the treatment time is 10-30 minutes.

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