JPH01169811A - Electrode structure - Google Patents

Abstract

PURPOSE:To connect exterior fitted parts in good performance both in electrical and mechanical terms by providing a non-electrolytic Ni alloy layer containing Sn on a clear conductive film containing Sn. CONSTITUTION:A non-electrolytic Ni alloy layer 15 containing Sn is provided in that region of a clear conductive film 13 containing Sn where at least exterior fitted parts are to be connected. In case these parts are connected with the clear conductive film 13 by soldering, the connection is made through the non- electrolytic Ni layer 15 containing Sn. Therefore, an affinity force acts between the Sn contained in the non-electrolytic Ni layer 15 and Sn contained in the solder. Thereby connections of the clear conductive film 13 with exterior fitted parts by the use of solder can be done with good close contact.

Description

Detailed Description of the Invention (Industrial Application Field) This invention provides a method for connecting external components such as lead wires and electronic components to a transparent conductive film containing tin using, for example, solder. The present invention relates to an electrode structure of a transparent conductive film suitable for electrically and mechanically making good connections.

(Prior Art) As is well known, transparent conductive films are used for display electrodes of liquid crystal display devices,
It is well known that it is used for surface electrodes of solar cells, etc., and is made of a thin film of an alloy of indium oxide and tin oxide (hereinafter sometimes referred to as ITO).

By the way, when using a transparent conductive film such as ITO formed on a transparent substrate such as glass as a display electrode or a surface electrode, electric signals are supplied to the transparent conductive film or via the transparent conductive film. In order to extract electrical signals, it is necessary to connect, for example, a driving circuit, lead wires, etc. (hereinafter, external devices may be referred to as components) to a portion of the transparent conductive film. However, since the transparent conductive film is a metal oxide, there are problems with its conductivity and the connectivity between the transparent conductive film and external components. Various methods of metallization have been proposed in the past.

Among these metallization methods, the method of externally attaching a transparent conductive film by applying electroless nickel to the area where parts are connected is said to be superior in terms of both productivity and cost. Examples of the prior art include those disclosed in the literature (Metal Surface Technology Association, 74th Lecture Conference Proceedings P, 8-9 "Study of electroless plating on transparent conductive crotch").

According to this document, when connecting the ITO film and external components with solder, an electroless plating layer of Ni (nickel)-P (phosphorus) is provided on the IT○ film, and the connection is made through this part. It has been reported that if this is done, the soldering properties will be improved compared to when these are directly connected with solder.

(Problems to be Solved by the Invention) However, the electrode structure disclosed in the above-mentioned document, which includes an electroless plated layer of N1-P on the transparent conductive layer, does not improve the hanging properties and conductivity. However, it could not necessarily be said to be the best one. Furthermore, according to the above-mentioned literature, soldering is easier with a structure that includes an electroless plating layer of N1-B (boron) on a transparent conductive film than with a structure that includes an N1-P layer. It has excellent conductivity, but on the other hand, it has been mentioned that the plating layer peels off from the transparent conductive film due to stress in the plating layer.

As described above, the conventional electrode structure was not satisfactory for connecting external components to a transparent conductive film.

This invention was made in view of these points,
Therefore, an object of the present invention is to provide an electrode structure of a transparent conductive film that can connect external components to the tin-containing transparent conductive film in good electrical and mechanical terms.

(Means for Solving the Problems) In order to achieve this object, according to the present invention, in an electrode structure for connecting an external component to a transparent conductive film containing tin, the transparent conductive film is At least the external part is characterized in that it comprises a tin-containing electroless nickel alloy layer on the area for connecting parts.

In carrying out the present invention, it is preferable that the electroless nickel alloy layer is the aforementioned electroless nickel alloy layer@Ni (nickel)-P (phosphorus) alloy, and that the tin content in this alloy layer is 1 to 2% by weight.

(Function) According to the electrode structure having such a configuration, since there is an affinity between tin contained in the transparent conductive film and tin contained in the electroless nickel alloy layer, the transparent conductive film and the electroless nickel The adhesion between the layers is improved.

Further, when an external component is connected to the transparent conductive film by solder, in the electrode structure of the present invention, the connection is made through an electroless nickel layer containing tin. Therefore, since affinity also exists between the tin contained in the electroless nickel layer and the tin contained in the solder, the soldering properties are improved. As a result, the transparent conductive film and external components can be connected with good adhesion using solder.

(Example) Examples of the electrode structure of the present invention will be described below. The electrode structure of the present invention is suitable for application to various devices including a transparent conductive film, such as display devices such as liquid crystal display devices and plasma discharge display devices, and in particular, solar cells. However, the electrode structure of the present invention will be explained below using a liquid crystal display device as an example.

In a liquid crystal display device, the alignment direction of the liquid crystal is changed, and
In order to enable humans to see this change, at least one of the substrates has an electrode made of a transparent conductive film. FIG. 1 is a sectional view roughly showing a portion of such a substrate.

In FIG. 1, 11 indicates, for example, a glass substrate. A transparent conductive film indicated by 13 is formed on this glass substrate 11. This transparent conductive film 13 may be, for example, the already explained IT○ film or a tin-containing film such as 5n02 (NE
SA membrane), etc. can be mentioned. still,
In a display device, most of the area of this transparent conductive film 13 is used for display, or on the other hand, it is necessary to supply electric signals for driving the liquid crystal to this transparent conductive film 13, so the transparent conductive film 13 is used for display purposes. Appropriate areas other than those used for display on the film 13 are used for connecting external components such as driving ICs and signal lines. In the electrode structure of the present invention, an electroless nickel alloy layer 15 containing tin is formed on at least the external region of the transparent conductive film 13 used for connecting components.

As the electroless nickel alloy for the tin-containing electroless nickel alloy layer 15, a nickel-phosphorus alloy or a nickel-boron alloy, which are known as typical electroless nickel alloys, can be used.

It has been found that such an electroless nickel alloy layer containing tin has good adhesion to the transparent conductive film below this layer, and also has good soldering properties. According to the inventor's detailed experiments, when the tin content in the electroless nickel alloy layer 15 of the nickel-phosphorous alloy is less than 1% by weight, the internal stress of this alloy layer is low; It was found that although the adhesion of the alloy layer to the transparent conductive film was good, on the other hand, the ability to hang onto the alloy layer was poor. Furthermore, if the tin content in the electroless nickel alloy layer 15 of the nickel-phosphorous alloy is greater than 2% by weight, the solderability to this alloy layer will be good, but the internal stress of this alloy layer will be high. It was found that this alloy layer peeled off from the transparent conductive film. These results show that when the tin content in the tin-containing nickel alloy layer 15 is 1 to 2% by weight, the connection between the external component and the transparent conductive film can be made well to the extent that there is no practical problem. It has been found that a particularly good connection can be achieved when the content is 1.2 to 1.5% by weight.

Next, in order to deepen the understanding of the electrode structure of the present invention, an example of a method for forming the electrode structure of the embodiment will be explained with reference to the flowchart of the manufacturing process shown in FIG. It should be noted that the numerical conditions, equipment used, chemicals used, etc. described in the following explanation are merely for illustrative purposes, and therefore, the present invention is limited only to the numerical conditions, equipment used, and chemicals used as described below. Please understand that this is not the case.

An IT'O film 13 as a transparent conductive film is formed on a glass substrate 11 by a conventionally known method 1 (FIG. 2, step 21). The IT○ film 13 in this example had a film thickness of about 1500 mm and a sheet resistance of 15 Ω/hole.

Next, a mask is formed on the ITO film 1 and the film 3 so as to expose only the area for connecting the parts 8 to the outside of the IT○ film 13. Such a mask can be constructed using, for example, a masking tape provided for electroless plating or a photoresist pattern.

Next, pretreatment for the formation of an electroless nickel alloy layer is
This is done as described below.

For the purpose of degreasing the area to be electroless plated, the ITO-coated substrate is immersed in an organic solvent such as acetone and heated for 10 minutes at room temperature.
Cleaning with one ultrasonic wave is performed under frequency division conditions (FIG. 2, step 22).

Next, the surface of the IT○ film 13 was coated with conditioner (10%
The IT○ film surface is roughened by immersing it in a hydrochloric acid solution for 1 minute. Next, this rough surface was coated with a sensitizer (SnCβ2
solution) for 3 minutes to adsorb tin ions Sn2+ on the ITO film surface (steps 23 and 24).

Next, in order to replace Sn2+ with palladium ion Pd2+, the glass substrate 11 with an ITO film is attached to an actihat (Pd2+).
dCρ2 solution) for 3 minutes (step 25).

In this way, palladium is selectively deposited on a predetermined region of the IT○ film 13 on the glass substrate 11.

The steps up to this point are conventionally known pretreatment steps for electroless plating, and palladium acts as a catalyst in electroless nickel alloy plating and contributes to the precipitation of nickel alloy. In the above-mentioned embodiment, separate solutions for the sensitizer and the activator are used, but a colloidal one-component type solution obtained by mixing these two solutions may also be used.

Next, electroless di-y-Kel alloy plating on the transparent conductive film, shown as step 26 in FIG. 2, is performed as described below.

The electroless plating bath used in this example was independently adjusted by the inventor, and consisted of 0.025 mol/I2 sodium stannate, 0.434 mol/I! Sodium citrate, 0.1 mol/β nickel sulfate, 0
．． 7 mol/β ammonium chloride and 0.072 mol/
Contains β sodium hypophosphite. Then, the pH of the plating bath was adjusted to 9 using ammonia water, and the plating solution was heated while stirring so that the temperature reached 90'C.

The pretreated ITO film-coated glass substrate is immersed in the plating bath adjusted as described above. As a result, ITO
Nickel alloy was deposited on the exposed portion of the film at a rate of about 1000λ/min, and an electroless nickel alloy layer 15 containing tin could be formed on the ITO crotch.

When this electroless nickel alloy layer 15 was analyzed using conventional chemical analysis, it was found to be an alloy containing 1.2% by weight of tin, 90.2% by weight of nickel, and 8.6% by weight of phosphorus. I understand.

Note that this invention is not limited to the embodiments described above.

In the above example, an electroless nickel-phosphorus alloy with tin added is provided on a transparent conductive film. However, an electroless nickel alloy with tin added to a nickel-boron alloy Even when the layer is provided on a transparent conductive film,
The adhesion between the two is improved as in the example. Therefore,
Since it becomes possible to reduce the thickness of the nickel-boron electroless alloy layer containing tin, it becomes possible to reduce the internal stress of this film as a result. This also makes it possible to alleviate the problems encountered when using a nickel-boron electroless alloy layer.

(Effects of the Invention) As is clear from the above description, the electrode structure of the present invention has a tin-containing electroless nickel alloy layer on a tin-containing transparent conductive film. There is an affinity between the tin contained in the film and the tin contained in the electroless nickel alloy layer, so the adhesion between the transparent conductive film and the electroless nickel layer is improved compared to conventional ones. .

Furthermore, when external components are connected to the transparent conductive film by soldering, there is an affinity between the tin contained in the electroless nickel alloy layer and the tin contained in the solder. The wetting of the solder to the layer 'i is improved.

Therefore, it is possible to provide an electrode structure of a transparent conductive film that can connect external components to the tin-containing transparent conductive film in good electrical and mechanical terms.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing an example of the electrode structure of the present invention, and FIG. 2 is a diagram showing the main flow of the manufacturing process for forming the electrode structure of the present invention. 11... Base 13... Transparent conductive film containing tin 15... Electroless nickel alloy layer containing tin. Patent applicant Oki Electric Industry Co., Ltd. 1 Glass substrate 15: Tin-containing electroless nickel alloy layer 13: Tin-containing transparent conductive film Cross-sectional diagram showing the electrode structure of this invention November 7, 1963 1-7-12 Toranomon, Minato-ku, Tokyo Name (029) Oki Electric Industry Co., Ltd. Representative Nobumitsu Kosugi 4 Agent 170 ffi (988) 5563
Address: 905 Ikebukuro White House Building, 1-20-5 Higashiikebukuro, Toshima-ku, Tokyo Contents of Drawing 7 Amendment Figure 2 of the drawing will be corrected as shown in the attached correction drawing. Diagram 3 showing the manufacturing process of the electrode structure of this invention Indication of Procedural Amendment 1 Case 1985 Patent Application No. 205507 1-7-12 Toranomon, Minato-ku, Tokyo Name (029) Oki Electric Industry Co., Ltd. Representative Nobumitsu Kosugi 4 agents 〒+70 2! (988)5563 address
56, 1-20 Higashiikebukuro, Toshima-ku, Tokyo Target of amendment Contents of amendment to drawing 7 attached to procedural amendment submitted on November 7, 1988

Claims (2)

[Claims] (1) An electrode structure characterized in that an electroless nickel alloy layer containing tin is provided on at least a region for connecting an external component of a transparent conductive film containing tin. (2) The electroless nickel alloy layer is made of Ni (nickel)
The electrode structure according to claim 1, characterized in that the electrode structure is made of a P (phosphorus) alloy, and the tin content in the alloy layer is 1 to 2% by weight.