JPH05274917A - Conductive transparent film of tin oxide - Google Patents

Abstract

PURPOSE:To provide a transparent conductive film of tin oxide having low sheet resistance and high bonding strength. CONSTITUTION:A substrate comprising soda lime glass 1 coated with a SiO2 film is first scribed to a 50mm square and cleaned with a solvent and demineralized water. Then, solution with 25g of SnCl4.H2O dissolved in 150ml of demineralized water is sprayed from an upper level toward to the substrate placed on a heated hot plate, and a transparent conductive film 3 of tin oxide not doped with fluorine is formed thereon to 100nm thickness. Thereafter, solution with 25g of SnCl4.6H2O and 10.58g of NH4F respectively dissolved in demineralized water is sprayed, and a transparent conductive film 4 of tin oxide doped with fluorine is formed to 200nm thickness. Furthermore, the prescribed SnO2 pattern is etched, and a Ni plated layer of 1mum thickness and a Au plated film 6 of 100nm thickness are respectively formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tin oxide transparent conductive film formed on a substrate.

[0002]

2. Description of the Related Art Conventionally, glass substrates having a transparent conductive film of tin oxide have been used in various applications such as solar cells and display devices. The transparent conductive film of tin oxide is, for example, silica coated glass (SC). (G.) A single layer film obtained by forming tin oxide on a substrate by a spray method or a CMD method (Chemical Mist Deposition Method).

In the prior art, the sheet resistance is reduced by doping the tin oxide transparent conductive film with fluorine.

[0004]

However, the substrate having the fluorine-doped tin oxide transparent conductive film can obtain a low sheet resistance value, but has a high adhesive strength of 1 kg / 2 mm □ or more (tin oxide transparent conductive film). Ni and A on the film
It is not possible to obtain (as measured by pulling the lead wire by soldering a lead wire to the surface thereof after plating with u), while having a tin oxide transparent conductive film not doped with fluorine. The substrate can obtain a high adhesive strength of 1 kg / 2 mm □ or more, but there is a problem that the sheet resistance value becomes higher by one digit than the above.

Therefore, an object of the present invention is to provide a tin oxide transparent conductive film having a low sheet resistance and a high adhesive strength by solving the problems of the above-mentioned conventional techniques.

[0006]

Means for Solving the Problems As a result of earnest studies for achieving the above object, the inventors of the present invention have formed a tin oxide transparent conductive film which is not doped with fluorine on a substrate, and formed a fluorine-containing transparent conductive film thereon. The inventors have found that the above-mentioned problems can be solved by forming a tin oxide transparent conductive film into which the above is doped to form a two-layer film, and have reached the present invention.

That is, according to the present invention, a film is formed on a substrate,
It is a two-layer film composed of a tin oxide transparent conductive film not doped with fluorine and a tin oxide transparent conductive film doped with fluorine, and a tin oxide transparent conductive film not doped with fluorine is formed on the substrate side. The present invention provides a characteristic transparent conductive film of tin oxide.

[0008]

According to the tin oxide transparent conductive film of the present invention, first, a fluorine-doped tin oxide transparent conductive film is formed on a substrate, and then a fluorine-doped tin oxide transparent conductive film is formed on this film. It can be obtained by forming a film.

For example, a silica-coated glass substrate (a substrate in which a SiO ₂ coating 2 is formed on a soda lime glass 1)
When the tin oxide transparent conductive film 3 not doped with fluorine and the tin oxide transparent conductive film 4 doped with fluorine are formed on the Ni plated layer 5 and the Au plated layer 6, the Ni plated layer At the interface between 5 and the fluorine-doped tin oxide transparent conductive film 4, a texture structure is formed by crystal grain growth on the surface of the fluorine-doped tin oxide transparent conductive film 4 (FIG. 1), and therefore the surface area is As a result, the bond between Ni and SnO ₂ : F becomes stronger and the bond strength becomes higher. The texture structure increases as the thickness of the tin oxide transparent conductive film increases.

Further, since there is no fluorine at the interface between the SiO ₂ film and the tin oxide transparent conductive film which is not doped with fluorine, it has a high adhesive strength, but the fluorine formed on this film is doped. If the film thickness of the formed tin oxide transparent conductive film is too thick, the fluorine contained in this film will exist at the interface, and the adhesive strength will be reduced.

On the other hand, when the film thickness of the fluorine-doped tin oxide transparent conductive film is thin, the sheet resistance is slightly higher than that of the conventional single-layer film made of only fluorine-doped tin oxide transparent conductive film. By increasing the thickness of the tin oxide transparent conductive film that is doped with fluorine, the fluorine spreads to the tin oxide transparent conductive film that is not doped with fluorine, so that a sheet resistance equivalent to that of the conventional single layer film can be obtained. Like

Therefore, the film thickness of the fluorine-doped tin oxide transparent conductive film and the fluorine-doped tin oxide transparent conductive film in the tin oxide transparent conductive film of the present invention are the same as those of the fluorine-doped tin oxide transparent conductive film. To a thickness such that the fluorine does not spread to the tin oxide transparent conductive film which is not doped with fluorine and the fluorine does not reach the interface between the tin oxide transparent conductive film which is not doped with fluorine and the SiO ₂ coating. It suffices to do so, and by forming the above-mentioned two-layer film with such a film thickness, it becomes possible to have both high adhesive strength and low sheet resistance.

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

[0014]

Example 1 First, a silica-coated glass substrate (a ready-made glass substrate in which the surface of soda lime glass was coated with a SiO ₂ film having a thickness of 100 nm) was scribed in a 50 mm square and washed with a solvent and pure water. Meanwhile, pure water 1
25 g of SnCl ₄ .6H ₂ O was dissolved in 50 ml to prepare a raw material liquid I for producing a transparent conductive film of tin oxide, and the raw material liquid I was
Spraying was performed from above the substrate placed on a hot plate heated to ℃ to form a SnO ₂ film having a film thickness of 100 nm and not doped with fluorine.

Next, to 150 ml of pure water, SnCl ₄ .6H ₂ O was added.
And 25 g of NH ₄ F and 10.58 g of NH ₄ F are dissolved to prepare a raw material liquid II for forming a transparent conductive film of tin oxide, and the raw material liquid II is sprayed in the same manner as described above to form a fluorine-doped SnO ₂ film having a film thickness of 50 nm. Was deposited. Next, a photoresist is uniformly applied to the substrate, prebaked at 120 ° C. for 30 minutes, and then irradiated with ultraviolet rays in accordance with a predetermined mask (2 mm □ pattern) to dissolve and remove the unirradiated resist to remove SnO ₂
The membrane was partially exposed.

Next, this substrate was pre-baked at 150 ° C. for 30 minutes, zinc powder was evenly dispersed on the substrate, and then the substrate was placed in an etching solution (HCl + FeCl ₃ ) to expose the exposed SnO ₂
The film was removed. After that, the resist was peeled off with a solvent to form a SnO ₂ pattern having a predetermined mask shape.

The sheet resistance of the obtained substrate was measured, and the results are shown in Table 1.

[0018]

[Table 1]

Next, selective electroless Ni plating was applied to the above substrate to form a Ni plating layer having a film thickness of 1 μm, and further substitutional electroless Au plating was applied to form an Au plating layer having a film thickness of 100 nm. Next, an L-type lead wire was soldered on the Au plated layer, and an adhesive strength test was performed by pulling the lead wire. The results are also shown in Table 1.

[0020]

[Example 2] A tin oxide transparent conductive film with a plated layer was prepared in the same manner as in Example 1 except that the raw material liquid II for preparing a tin oxide transparent conductive film was sprayed to form a SnO ₂ film having a thickness of 100 nm. A glass substrate was prepared, and the same measurement and test as in Example 1 were performed during that period, and the results are also shown in Table 1.

[0021]

[Example 3] A tin oxide transparent conductive film with a plated layer was prepared in the same manner as in Example 1 except that the raw material liquid II for preparing a tin oxide transparent conductive film was sprayed to form a SnO ₂ film having a thickness of 400 nm. A glass substrate was prepared, and the same measurement and test as in Example 1 were performed during that period, and the results are also shown in Table 1.

[0022]

[Example 4] A tin oxide transparent conductive film with a plated layer was prepared in the same manner as in Example 1 except that the raw material liquid II for preparing a tin oxide transparent conductive film was sprayed to form a SnO ₂ film having a thickness of 700 nm. A glass substrate was prepared, and the same measurement and test as in Example 1 were performed during that period, and the results are also shown in Table 1.

[0023]

[Comparative Example 1] S by the raw material liquid I for producing a transparent conductive film of tin oxide
A tin oxide transparent conductive film with a plated layer was formed in the same manner as in Example 1 except that the SnO ₂ film having a thickness of 150 nm was formed by using the raw material liquid II for forming the tin oxide transparent conductive film without forming the nO ₂ film. A glass substrate having the above was prepared, and the same measurement and test as in Example 1 were performed during that time, and the results are also shown in Table 1.

[0024]

[Comparative Example 2] S by the raw material liquid I for producing a transparent conductive film of tin oxide
A tin oxide transparent conductive film with a plated layer was formed in the same manner as in Example 1 except that the SnO ₂ film having a film thickness of 200 nm was formed by using the raw material liquid II for forming the tin oxide transparent conductive film without forming the nO ₂ film. A glass substrate having the above was prepared, and the same measurement and test as in Example 1 were performed during that time, and the results are also shown in Table 1.

[0025]

[Comparative Example 3] S by the raw material liquid I for producing a transparent conductive film of tin oxide
A tin oxide transparent conductive film with a plated layer was formed in the same manner as in Example 1 except that the SnO ₂ film having a film thickness of 500 nm was formed by using the raw material liquid II for forming the tin oxide transparent conductive film without forming the nO ₂ film. A glass substrate having the above was prepared, and the same measurement and test as in Example 1 were performed during that time, and the results are also shown in Table 1.

[0026]

[Comparative Example 4] S by the raw material liquid I for producing a transparent conductive film of tin oxide
A tin oxide transparent conductive film with a plated layer was formed in the same manner as in Example 1 except that the SnO ₂ film having a thickness of 800 nm was formed by using the raw material liquid II for forming the tin oxide transparent conductive film without forming the nO ₂ film. A glass substrate having the above was prepared, and the same measurement and test as in Example 1 were performed during that time, and the results are also shown in Table 1.

As can be seen from Table 1, when the thickness of the SnO ₂ film is 150 to 200 nm (Example 1, Example 2, Comparative Example 1, Comparative Example 2), the adhesive strength is two-layer film (implemented). The values of Examples 1 and 2) are higher than those of the monolayer films (Comparative Examples 1 and 2), indicating that the adhesive strength is improved. On the other hand, a film thickness of 500 to 800 nm (Example 3, Example 4,
In the case of Comparative Examples 3 and 4), no significant difference was observed between the bilayer film (Examples 3 and 4) and the monolayer film (Comparative Examples 3 and 4). Regarding the sheet resistance, the two-layer film (Examples 1 to 4) and the single-layer film (Comparative Examples 1 to 4) showed almost the same value.

[0028]

The thickness of SnO ₂ film [Example 5] not doped with SnO ₂ film and the fluorine doped with fluorine, the following tests were performed to examine the relationship between the peel point in adhesion strength test.

[0029] First, a SnO ₂ film and fluorine in the silica-coated glass substrate is not doped with fluorine by forming a SnO ₂ film doped. The thickness of these SnO ₂ films is as shown in Table 2. Next, a 1.0 μm thick Ni plating layer was formed on the fluorine-doped SnO ₂ film, and a 0.1 μm thick Au plating layer was further formed thereon.

[0030]

[Table 2]

Next, a lead wire is soldered to the surface of the Au plating layer of each of the above-mentioned substrates, and peeling is caused by pulling the lead wire, and the relationship between the peeled portion and the pulling force is shown in FIGS. Is shown in the graph. In the graphs of FIGS. 3 to 8, when the glass substrate is peeled off due to the hollow portion and the shaded portion is peeled at the boundary between the Ni plating layer and the SnO ₂ film which is not doped with fluorine, The part is a case where the SiO ₂ film and the SnO ₂ film not doped with fluorine are separated from each other.

As can be seen from FIGS. 3 and 4, when the thickness of the fluorine-doped SnO ₂ film is small (the thickness of the fluorine-doped SnO ₂ film is 0 or 400 Å), the Ni plating layer 5 is used. The adhesion strength between the fluorine-doped SnO ₂ film 4 and the fluorine-doped SnO ₂ film 4 is low because a texture structure is not formed at the interface (FIG. 2), while the adhesion strength between the fluorine-undoped SnO ₂ film and the SiO ₂ film is However, since there is no fluorine at the interface, it is high as in the case of the SnO ₂ single layer film not doped with fluorine. Therefore, the interface or the thickness of SnO ₂ film is thinner doped with fluorine, the case of not forming the SnO ₂ film doped with fluorine, and SnO ₂ films most part doped with Ni plating layer and fluorine Peeling occurred.

As can be seen from FIGS. 5 and 6, when the thickness of the fluorine-doped SnO ₂ film is 1000 or 2000 angstroms, the total thickness of the SnO ₂ film is 1800.
Approximately 2800 angstroms, a texture structure is formed to some extent at the interface between the Ni plating layer 5 and the fluorine-doped SnO ₂ film 4 (FIG. 1).
Therefore, the adhesive strength at the interface increases. on the other hand,
The adhesive strength at the interface between the fluorine-undoped SnO ₂ film and the SiO ₂ coating is as high as that of the fluorine-undoped SnO ₂ single-layer film because there is no fluorine at the interface. Therefore, peeling occurred from both the interface between the Ni plating layer and the fluorine-doped SnO ₂ film and the interface between the fluorine-undoped SnO ₂ film and the SiO ₂ film.

As can be seen from FIGS. 7 and 8, when the film thickness of the fluorine-doped SnO ₂ film is large (the film thickness of the fluorine-doped SnO ₂ film is 4000 or 7000 Å), the Ni plating layer and Since the texture structure is formed at the interface with the fluorine-doped SnO ₂ film, the adhesive strength at the interface is high, but the fluorine of the fluorine-doped SnO ₂ film is different from the fluorine-undoped SnO ₂ film. Since it exists even at the interface with the SiO ₂ coating, the adhesive strength at this interface becomes low. Therefore, most of the peeling occurred at the interface between the SnO ₂ film not doped with fluorine and the SiO ₂ film.

Further, SnO not doped with fluorine
_{For the two-} layer film, the fluorine-doped SnO ₂ single-layer film, and the two-layer film consisting of a fluorine-undoped SnO ₂ film and a fluorine-doped SnO ₂ film, the adhesion strength and SnO 2 The relationship with the film thickness of the _two films as a whole is shown in the graph of FIG.

As can be seen from FIG. 9, in the case of a fluorine-undoped SnO ₂ single layer film, since fluorine does not exist at the interface between the fluorine-undoped SnO ₂ film and the SiO ₂ film, the film thickness is The higher the thickness, the higher the adhesive strength (the thicker the film, the more the texture structure is formed). Also, in the case of a SnO ₂ single layer film doped with fluorine, the adhesive strength was low because of the presence of fluorine at the interface, but the adhesive strength increased as the film thickness increased, as described above.

On the other hand, SnO not doped with fluorine
_In the case of a two-layer film composed of two films and a fluorine-doped SnO ₂ film, when the fluorine-doped SnO ₂ film has a certain thickness, SnO that is not fluorine-doped is used.
_Since there is no fluorine at the interface between the ₂ film and the SiO ₂ film,
It had a high adhesive strength as in the case of the SnO ₂ single layer film not doped with fluorine. However, when the thickness exceeds a certain level, fluorine comes to exist at the interface, so that the adhesive strength is reduced to the same as that of the SnO ₂ single layer film doped with fluorine.

[0038]

[Embodiment 6] A substrate having a tin oxide transparent conductive film similar to that of Embodiment 5 is used, and a fluorine-doped SnO ₂ single-layer film, a fluorine-doped SnO ₂ single-layer film, and a fluorine-doped SnO ₂ single-layer film. For each of the two-layer film consisting of a non-doped SnO ₂ film and a fluorine-doped SnO ₂ film,
The relationship between the sheet resistance and the film thickness of the entire SnO ₂ film was investigated, and the results are shown in the graph of FIG.

As can be seen from FIG. 10, in all cases, the thicker the film thickness, the lower the sheet resistance. In addition, both the SnO ₂ film not doped with fluorine and the SnO ₂ film doped with fluorine were used. layer film is lower than the SnO ₂ monolayer film not doped with fluorine had a similar sheet resistance and SnO ₂ monolayer film doped fluorine.

[0040]

The tin oxide transparent conductive film of the present invention comprising a two-layer film of a tin oxide transparent conductive film doped with fluorine and a tin oxide transparent conductive film not doped with fluorine is 1 kg / 2 mm.
□ In addition to having a high adhesive strength as described above, it has a sheet resistance equivalent to that of a single-layer film of a fluorine-doped tin oxide transparent conductive film.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a tin oxide transparent conductive film (two-layer film) on which a texture structure is formed.

FIG. 2 is a side sectional view showing an example of a tin oxide transparent conductive film (two-layer film) in which a texture structure is not formed.

FIG. 3 is a graph showing peeling points in an adhesive strength test of a substrate having a SnO ₂ single layer film not doped with fluorine.

FIG. 4 SnO ₂ film not doped with fluorine (1000
FIG. 3 is a graph showing the peeling points in an adhesive strength test of a substrate having a two-layer film composed of a SnO ₂ film (400 angstrom) doped with Å) and fluorine.

FIG. 5: SnO ₂ film not doped with fluorine (1000
FIG. 3 is a graph showing peeling points in an adhesive strength test of a substrate having a two-layer film made of a SnO ₂ film (1000 angstrom) doped with Å) and fluorine.

FIG. 6 SnO ₂ film not doped with fluorine (1000
FIG. 3 is a graph showing peeling points in an adhesive strength test of a substrate having a two-layer film made of a SnO ₂ film (2000 angstroms) doped with angstrom) and fluorine.

FIG. 7: SnO ₂ film without fluorine doping (1000
FIG. 3 is a graph showing peeling points in an adhesive strength test of a substrate having a two-layer film made of a SnO ₂ film (4000 angstroms) doped with Å) and fluorine.

FIG. 8: SnO ₂ film not doped with fluorine (1000
FIG. 3 is a graph showing peeling points in an adhesive strength test of a substrate having a two-layer film made of a SnO ₂ film (7000 angstrom) doped with Å) and fluorine.

FIG. 9 is a SnO ₂ single layer film not doped with fluorine;
6 is a graph showing the relationship between the adhesive strength and the film thickness of a fluorine-doped SnO ₂ single layer film, and a two-layer film composed of a fluorine-undoped SnO ₂ film and a fluorine-doped SnO ₂ film.

FIG. 10 shows a fluorine-doped SnO ₂ single-layer film, a fluorine-doped SnO ₂ single-layer film, and a _two- layer film including a fluorine-undoped SnO ₂ film and a fluorine-doped SnO ₂ film. 5 is a graph showing the relationship between the sheet resistance and the film thickness of FIG.

[Explanation of symbols]

1 soda lime glass 2 SiO ₂ coating 3 Fluorine-doped tin oxide transparent conductive film 4 Fluorine-doped tin oxide transparent conductive film 5 Ni plating layer 6 ‥‥‥ Au plating layer

Claims (1)

[Claims] 1. A two-layer film comprising a tin oxide transparent conductive film which is formed on a substrate and which is not doped with fluorine and a tin oxide transparent conductive film which is doped with fluorine, wherein the substrate side is doped with fluorine. A transparent tin oxide conductive film, characterized in that a transparent tin oxide conductive film is formed.