JPH11352074A - Inspection of connection part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and easily inspect a connection part obtained by making the electrode formed on a flexible substrate in a short strip shape and the electrode formed on a printed circuit board in a short strip shape face each other to connect them under heating and pressure. SOLUTION: A light source is arranged in a state almost crossing the wiring direction of the electrode 4 formed on a flexible substrate 2 and obliquely upward on the side of the connection plate, with respect to the electrode forming surface and the connection part is visually observed from the position 11 facing the light source so as to hold the connection part on the side of the flexible substrate. A shadow is formed along the fine unevenness formed on the surface of the flexible substrate of the connection, part and uneveness is can be visually observed in good contrast in a shading (bright and angle) state from a direction facing opposite the light source through the connection part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a connection between an electrode of a flexible substrate such as a tape carrier package and an electrode of a printed circuit board.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have rapidly penetrated the market, and their applications have been expanding to OA, consumer, and industrial applications. Demand for cost reduction is increasing. Amid such market demands, improving yield has become an issue.
It is an important issue to prevent outflow of a defect caused by a foreign matter to a post-process.

For example, at a connection between an electrode of an input terminal of a tape carrier package, which is a flexible substrate, and an electrode of a printed circuit wiring board, foreign matter is stochastically mixed in, and a short circuit occurs between adjacent electrodes. Or poor connection of the electrodes. If a panel containing foreign matter in the connection between the input terminal of the tape carrier package and the electrode of the printed circuit board is overlooked in the inspection process and becomes defective in the subsequent process, it is disadvantageous not only in terms of manufacturing costs but also in terms of man-hours. Becomes In addition, the discovery of defects after market distribution must of course be prevented. As described above, detection in the previous step is extremely important.

At present, as a method of connecting a tape carrier package connected to a liquid crystal panel and a printed circuit wiring board, a method using soldering and a method using an anisotropic conductive adhesive sheet are known. The former connection method by soldering is a method that has been used in the past, and the electrode of the input terminal of the tape carrier package is exposed even after connection, and the connection part after connection can usually be easily inspected with a microscope. Was.

However, in recent years, the input terminal of the tape carrier package has been miniaturized with the increase in the definition of the liquid crystal panel, and the latter method using an anisotropic conductive adhesive sheet which enables connection at a narrower pitch has been widely used. Became used. FIG. 2 shows the shape of the tape carrier package at this time.
FIG. 3 shows a cross section of the input terminal portion. As shown in FIGS. 2 and 3, the tape carrier package 2
The electrodes 4 of the input terminals 3 are formed on a base film 6. Reference numeral 5 denotes an output terminal of the tape carrier package 2. When connecting to the electrodes of the printed circuit wiring board, both electrode forming surfaces are opposed to each other, and they are bonded by hot pressing through an anisotropic conductive adhesive sheet. Therefore, after the connection, the electrode forming surface is covered with the base film 6.

[0006]

The electrodes 4 of the input terminals 3 of the tape carrier package 2 and the printed circuit wiring board 7
FIG. 4 shows a state of the connection portion after the connection with the electrode 8 of FIG. As shown in FIG. 4, regular irregularities are formed along the electrodes 4 on the surface of the flexible base film 6. In an ordinary microscope, since the light is emitted from a light source at an angle of about 90 degrees with respect to the electrode forming surface of the tape carrier package 2, the contrast of minute irregularities formed on the surface of the tape carrier package 2 is poor, and the connection state is improved. I can't observe. Further, when a foreign matter 10 is interposed between the electrode 4 of the tape carrier package 2 and the electrode 8 of the printed circuit wiring board 7, minute projections formed on the surface of the tape carrier package 2 due to the foreign matter 10 are easily overlooked. And tape carrier package 2
Since it is difficult to directly detect the foreign matter from the side, there is a problem that the foreign matter cannot be determined as a foreign matter-containing product.

The present invention has been made to solve the above-mentioned conventional problems, and has an electrode formed in a strip shape on a flexible substrate and an electrode formed in a strip shape on a printed circuit wiring board are opposed to each other. It is an object of the present invention to provide a method for inspecting a connection portion obtained by connecting with pressure by a simple method, thereby enabling and facilitating an inspection operation.

[0008]

In order to achieve the above object, a method for inspecting a connection portion according to the present invention comprises an electrode formed in a strip shape on a flexible substrate and a strip shape on a printed circuit wiring board. A method of inspecting the connection portion after facing the electrodes formed on the flexible substrate and connecting them by heat and pressure, the method being substantially orthogonal to the wiring direction of the electrodes formed on the flexible substrate,
And installing a light source obliquely above the flexible substrate side with respect to the electrode forming surface, and inspecting the connection part from a position facing the light source with the connection part on the flexible substrate side interposed therebetween. Features.

When electrodes of a flexible substrate such as a tape carrier package and electrodes of a printed circuit wiring board are connected by heat and pressure, as shown in FIG. A portion having a mark has a convex portion according to the thickness of the electrode, and a portion having no electrode has a concave portion. According to the above configuration of the present invention, when inspecting the appearance of such a connection portion, the light source is disposed substantially orthogonal to the wiring direction of the electrodes on the flexible substrate and obliquely above the flexible substrate side. Therefore, the yin and yang are formed along the minute unevenness on the surface of the flexible substrate at the connection portion, and the unevenness is visually observed with good contrast in a yin and yang (bright and dark) state from the direction facing the light source with the connection portion interposed therebetween. be able to. When a foreign substance is interposed between the electrode of the flexible substrate and the electrode of the printed circuit wiring board, a projection (projection) is formed on the surface of the flexible substrate, which is clearly different from that of the electrode. Therefore, the yin and yang of the portion become irregular, and it can be easily confirmed that foreign matter is mixed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below using embodiments with reference to the drawings.

FIG. 1 is a schematic diagram of an inspection method according to an embodiment of the present invention.

Electrodes (not shown) are formed on the liquid crystal panel 1. After an anisotropic conductive adhesive sheet (not shown) is attached on the electrodes, a flexible tape carrier package 2 is formed. The output terminal 5 and the electrode of the liquid crystal panel 1 face each other, and are aligned and overlapped. Thereafter, heat is applied from the tape carrier package 2 side by a constant-heating bonding tool to electrically connect the electrode of the output terminal 5 of the tape carrier package 2 and the electrode of the liquid crystal panel 1.

Next, the electrodes 8 of the printed circuit wiring board 7 are
An anisotropic conductive adhesive sheet (not shown) is attached, and the input terminals 3 of the tape carrier package 2 and the electrodes 8 of the printed circuit wiring board 7 face each other, are aligned, and are overlapped.
Thereafter, heat and pressure are applied from the side of the tape carrier package 2 with a bonding tool of a constant heating method, and the electrodes 4 of the input terminals 3 of the tape carrier package 2 and the electrodes 8 of the printed circuit wiring board 7 are electrically connected.

After the connection, the connection between the electrode 4 of the tape carrier package 2 and the electrode 8 of the printed circuit board 7 is inspected.

At this time, the light source 9 is installed at a position facing the observer 11 with respect to the connection portion. The position of the light source 9 is set so that the angle φ between the wiring direction of the electrode 4 formed on the tape carrier package 2 and the wiring direction is substantially perpendicular to the plane including the electrode forming surface, that is, φ is preferably 70 to 110 degrees. More preferably, it should be approximately 90 degrees. Light source 9
Is preferably 30 to 60 degrees, more preferably approximately 4 degrees, which is an angle θ formed diagonally above the tape carrier package 2, that is, the surface including the electrode forming surface at the connection portion to be observed.
Be 5 degrees. By arranging the light source at the above-described position, it is possible to observe the yin and yang based on the regular unevenness formed on the tape carrier package 2 at the electrode connection portion with good contrast. In this embodiment, a fluorescent lamp is used as the light source 9.

In the inspection, the light source 9 is placed across the connection to be observed.
The observation is performed by visually observing the surface of the input terminal 3 of the tape carrier package 2 from the direction (the position of the observer 11) facing the camera.

Input terminal 3 of tape carrier package 2
When the electrodes 4 of the printed circuit board 7 are connected to the electrodes 8 of the printed circuit wiring board 7 by heat and pressure, as shown in FIG. Protrusions are formed correspondingly, and conversely, recesses are formed in portions without the electrodes 4. Therefore, according to the above-described method, the light illuminates the light source 9 obliquely from above, so that the light hits the light source side at the top of the projection, and the contour of the top of the projection is bright when viewed from the observer side, and the bottom of the projection is The part becomes a shadow, and the unevenness can be easily confirmed in a yin-yang (light and dark) state, and the quality of the connection can be determined. Further, as shown in FIG. 4, when a foreign substance 10 is interposed between the electrode 4 of the tape carrier package 2 and the electrode 8 of the printed circuit board 7, the electrode is provided on the surface of the input terminal 3 of the tape carrier package 2. Since a projection (projection) that is clearly different from the one is formed, the state of the yin and yang (bright and dark) becomes irregular unlike the others, and the foreign matter 10
Can be easily confirmed to be present. Thereby, it can be determined as a foreign matter-containing product.

The present invention is not limited to the above embodiment. For example, as the light source 9, an incandescent lamp, a halogen lamp, a fluorescent lamp, a mercury lamp, a xenon lamp, or the like can be appropriately selected and used depending on the situation.

[0019]

As described above, according to the method for inspecting a connection portion according to the present invention, the light source is disposed substantially orthogonal to the wiring direction of the electrodes on the flexible substrate and obliquely above the flexible substrate side. Since it is installed, the yin and yang are formed along the minute unevenness formed on the surface of the flexible substrate at the connection portion, and the unevenness is visually observed from the direction facing the light source across the connection portion in a state of yin and yang (bright and dark). Observation can be made with good contrast. When foreign matter is present at the connection part, a convex portion (projection) is formed on the surface of the flexible substrate, which is clearly different from that of the electrode, so that the yin and yang of the part becomes irregular, and the foreign matter is removed. It can be easily confirmed that they are mixed. As a result, since it can be immediately determined that the product is a foreign matter-containing product in the inspection process, it is possible to suppress the occurrence of defects in the subsequent process. This has the effect of reducing manufacturing costs and improving the reliability of market quality, and is extremely useful in practice.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an example of a method for inspecting a connection portion between an input terminal electrode of a tape carrier package and an electrode of a printed circuit wiring board according to an embodiment of the present invention.

FIG. 2 is a plan view of the tape carrier package before hot pressing.

FIG. 3 is a partially enlarged cross-sectional view of the tape carrier package before hot pressing.

FIG. 4 is a partially enlarged cross-sectional view of a connecting portion after hot pressing.

[Description of Signs] 1 LCD panel 2 Tape carrier package 3 Input terminal of tape carrier package 4 Electrode of input terminal of tape carrier package 5 Output terminal of tape carrier package 6 Base film of tape carrier package 7 Printed circuit wiring board 8 Printed circuit Electrode of wiring board 9 Light source 10 Foreign matter 11 Observer

Claims (5)

[Claims] 1. An electrode formed in a strip shape on a flexible substrate and an electrode formed in a strip shape on a printed circuit wiring board are opposed to each other and connected by heat and pressure, and then the connection portion is inspected. A method comprising: disposing a light source substantially orthogonal to a wiring direction of an electrode formed on the flexible substrate and obliquely above the flexible substrate side with respect to an electrode forming surface; An inspection method of the connection portion, wherein the connection portion is inspected from a position facing the light source with the connection portion on the conductive substrate side interposed therebetween. 2. The method according to claim 1, wherein the light source is an incandescent lamp, a halogen lamp, a fluorescent lamp, a mercury lamp, or a xenon lamp. 3. The method according to claim 1, wherein the flexible substrate constitutes a liquid crystal display device. 4. The inspection method for a connection part according to claim 1, wherein the light source is installed at a position of 30 to 60 degrees with respect to the electrode forming surface in the connection part. 5. The method according to claim 5, wherein the light source is connected to the connecting portion by a distance of 70 to 70 with respect to a wiring direction of an electrode formed on the flexible substrate.
The method for inspecting a connection part according to claim 1, wherein the connection part is installed at a position of 110 degrees.