JP2533225B2 - How to connect TAB tape - Google Patents

Description

[Detailed Description of the Invention] [Outline] Regarding the connection method of the TAB tape, when connecting the substrate terminal portion of the liquid crystal display panel and the tape terminal portion of the TAB tape, it is possible to replace the TAB tape that has been temporarily connected, and connect it. TAB that connects the tape terminal part of the TAB tape with the conductive film for connection to the substrate terminal part on the glass substrate of the liquid crystal display panel for the purpose of ensuring the quality, reliability and yield of the liquid crystal display panel.
In the tape connecting method, after temporarily connecting the conductive film for connection to either one of the substrate terminal portion or the tape terminal portion by a semi-curing treatment, the terminals are aligned and the conductive film for connection is half-finished again. A TAB tape connection method is configured so that temporary connection is performed by curing treatment, and after the connection state of both terminal portions is inspected and confirmed, the connection conductive film is treated under curing conditions to achieve the main connection state.

[Industrial applications]

The present invention relates to an improvement in a method of connecting a TAB tape to an electrode terminal portion of a liquid crystal display panel or the like.

2. Description of the Related Art In recent years, the development of display devices has been remarkable, and in particular, flat displays have rapidly spread due to their thinness and light weight. Among them, liquid crystal display devices have a low driving voltage and are low in price, so that they are being actively introduced into the field of office automation equipment such as personal computers and word processors.

Since liquid crystal display panels used for these purposes are required to display characters and figures, they are inevitably moving toward large screens, multiple pixels, and high definition, and the number of display line electrodes for liquid crystal display panels is There are some hundreds or more, and it is becoming more and more important to surely connect with the driving circuit and reduce the damage of the expensive liquid crystal display panel.

[Conventional technology]

In general, a liquid crystal display device has two glass substrates on which stripe-shaped transparent electrodes (ITO: In ₂ O ₃ -SnO ₂ ) are formed, both electrode surfaces are opposed to each other, and are orthogonal to each other with a space of about 10 μm. Stick together. Then, when liquid crystal is injected into the gap formed by the two glass panels and a voltage is applied,
The electro-optical effect of the liquid crystal and the polarizing plates disposed on both sides serve as optical switches at the intersections of the two striped electrodes to form pixels, thereby displaying light and dark.

The ends of the striped transparent electrodes form substrate terminal portions, which are appropriately connected to drive circuits so that the intersections of the striped electrodes are drive-controlled during operation.

TAB tape (Tape Auto-mated) is currently the most commonly used method of connecting circuit board terminals to drive circuits.
This is the so-called TAB method using Bonding).

FIG. 3 is a diagram showing an example of connection between the drive electrode substrate terminal portion and the TAB tape. FIG. 3 (a) is a plan view, FIG. 3 (b-1),
(B-2) is a sectional view taken along the line A-A '.

In the figure, 10 is a glass substrate of a liquid crystal display panel, for example, a transparent glass plate having a size of 200 mm × 300 mm and a thickness of 1.1 mm, and 11a to 11g are striped transparent electrodes (ITO: In ₂ O ₃ -S).
nO ₂ ), for example, width 0.27 mm, thickness 100 nm, spacing between adjacent electrodes
The pitch between electrodes is 0.03 mm, that is, about 0.3 mm. 1 is the transparent electrode (IT
Substrate terminal portion formed less than O), in this example, at the same pitch as the stripe-shaped transparent electrodes 11a to 11g, the width is 0.
It is composed of electrode rows 1a to 1g of the terminal portion of the substrate, which are 15 mm and have a space of 0.15 mm.

Reference numeral 20 is a so-called printed wiring board in which a large number of conductor wirings are provided on a flexible thin resin board using a TAB tape. Reference numeral 2 is a tape terminal portion, and the terminal rows 1a to 1g of the board terminal portion and the terminal rows 2a to 2g of the tape terminal portion formed with the same width and at the same interval are provided at the end of the TAB tape. There is. 100 is an IC that drives a liquid crystal display panel with a driver IC mounted on a TAB tape.

Reference numeral 3 is a conductor film for connection, in which a conductive particle, for example, a metal particle 30 such as Ni having a particle diameter of about 10 μm is mixed with a resin that functions as an adhesive, for example, a thermoplastic or semi-thermosetting resin, and a thickness of 0.01 It is made into a film of ~ 0.05mm, and when it is sandwiched between electrode terminals and thermocompression bonded, it conducts in the film thickness direction, but maintains insulation in the film surface direction. For example, it is an anisotropic conductive film. .

Now, for example, the substrate terminal portion 1 of the liquid crystal display panel and the TA
The conductive film 3 for connection is provided between the B tape 20 and the tape terminal portion 2.
The terminal rows 1a to 1g and 2a to 2g are superposed so as to match each other by sandwiching them, and, for example, if they are heated and pressed at 150 ° C. and 20 kg / cm ² , the board terminal portion 1 and the tape terminals are connected via the metal particles 30. The part 2 is electrically connected and mechanically bonded and fixed.

FIG. 4 is a process diagram showing an example of a conventional TAB tape connection method, and specifically shows the connection method of the example shown in FIG. 3 in the order of processes.

First, the conductive film 3 for connection to the substrate terminal portion 1 of the glass substrate 10,
For example, an anisotropic conductive film is temporarily connected. The temporary connection condition may be looser than the main connection condition. next,
The TAB tape 20 is overlapped on the temporarily connected conductive film 3 for connection, and the terminals are aligned. For alignment, for example, the alignment mark on the glass substrate 10 shown in FIG.
41 with the alignment mark 42 on the TAB tape
This can be easily done by the method of matching on the V monitor.

If the main connection is performed under a predetermined curing condition of the conductive film 3 for connection after the alignment is completed, both terminal portions are firmly bonded and fixed. After that, the appearance of the connection part is inspected and non-defective products proceed to the next process, and defective products are discarded.

[Problems to be Solved by the Invention]

However, the electrode width of each of the electrode terminal rows is very narrow at 0.15 mm, and there is a tendency for the electrode width to become further smaller due to future demands for higher definition of display and for colorization. Therefore, ideal connection between the two electrode terminal rows becomes increasingly difficult.

For example, as schematically shown in FIG. 3 (b-1), insulative dust 50 and conductive foreign matter 2 are present between both terminals to cause conduction failure or short circuit failure, or In some cases, the positional deviation as schematically shown in (b-2) may occur, which may cause a conduction failure or a short circuit failure.

In the conventional connection method shown in FIG. 4, even if the appearance is inspected after the main connection and the inconvenience is found, the glass substrate 10 and the TAB tape 20 are firmly adhered to each other, and the When it is attempted to peel it off, the substrate terminal portion 1 of the glass substrate 10 is damaged and cannot be reused, and there is a serious problem that the entire liquid crystal display panel becomes defective and causes a large damage. .

[Means for solving the problem]

The above-mentioned problem is the TAB tape connecting method in which the tape terminal portion 2 of the TAB tape 20 is connected to the board terminal portion 1 on the glass substrate 10 of the liquid crystal display panel by using the conductive film 3 for connection. Alternatively, after temporarily connecting the connecting conductive film 3 to either one of the tape terminal portions 2 by semi-curing treatment, the terminal portions 1 and 2 are aligned and the connecting conductive film 3 is temporarily cured by semi-curing treatment again. Connect and connect both terminals
After the connection state of 1 and 2 is inspected and confirmed, the connection conductive film 3 is treated under curing conditions to obtain the main connection state.
It can be solved by connecting the B tape.

[Action]

According to the method of the present invention, the substrate terminal portion 1 on the glass substrate 10
And the tape terminal portion 2 of the TAB tape 20 with the conductive film 3 for connection.
First, align the parts, make a temporary connection, and inspect the appearance before the main connection. If there is dust 50, foreign matter 60, or misalignment, remove the connection part and remove the new one.
The TAB tape 20 is temporarily connected again by the same procedure, and after the appearance inspection is passed, the main connection is made, so that the final connection failure can be greatly reduced.

〔Example〕

As the glass substrate 10 of the liquid crystal display panel, for example, a transparent glass plate having a size of 200 mm × 300 mm and a thickness of 1.1 mm is used, and a striped pattern made of a mixed oxide of In ₂ O ₃ —SnO ₂ is formed thereon. A transparent electrode (ITO) was formed. The width of the electrode terminal of the board terminal portion 1 formed at the end is 0.15 mm and the thickness is 100 n
m, spacing between adjacent terminals 0.15 mm, that is, the pitch between terminals is 0.3 mm
It is a degree.

On the other hand, the TAB tape 20 is provided with the terminal rows 1a to 1g of the substrate terminal section 1 and the terminal rows 2a to 2g of the tape terminal section 2 formed at the same width and at the same intervals at the ends. .

The required positions of the board terminal portion 1 and the tape terminal portion 2 are, for example, the alignment marks 41 and the marks shown in FIG.
42, for example, 0.2φ ring (for example, ITO on the substrate side
On the other hand, a metal conductor) is formed on the TAB tape side.

Other details are the same as those shown in the plan view of FIG. 3 (a), and detailed description thereof will be omitted. However, FIG. 3 shows a part of the whole, and in general, several 100 terminals are arranged on the substrate side and a plurality of tapes having several tens terminals are generally used on the TAB tape side.

An anisotropic conductive film (for example, a thermoplastic conductive film) is used as the connecting conductive film 3.

FIG. 1 is a process chart showing an embodiment method of the present invention, and specifically shows the connection method of the present invention when the above-mentioned embodiment members are used in the order of steps.

First, the conductive film 3 for connection to the substrate terminal portion 1 of the glass substrate 10,
For example, the anisotropic conductive film is temporarily connected. Temporary connection conditions, for example, 140 ° C., under pressure of 10 kg / cm ^2. 2 to
Heat for 3 seconds to make the connection. For such pressurization / heating, for example, a known wedge type (in this example, a length of 50 m
It is possible to use a heating head with a width of 3 mm and a width of 3 mm to heat 60 to 80 terminals together)).

Next, the tape terminal portion 2 of the TAB tape 20 is superposed and aligned on the conductive film 3 for connection which is temporarily connected to the substrate terminal plate 1 of the glass substrate 10. For alignment, for example, the third
Alignment mark 41 and TAB on the glass substrate 10 shown
The alignment mark 42 on the tape can be matched on the TV monitor with a microscope.

After completing the alignment, make the temporary connection. The temporary connection condition may be, for example, according to the above-mentioned temporary connection condition. After the temporary connection and the temporary connection, the glass substrate 10 and the TAB tape 20 are temporarily fixed, and the connection resistance is still high, but it cannot be easily removed.

In this state, a visual inspection, for example, a microscopic inspection is performed, and a successful connection is made. The connection conditions are, for example, heating at 20 ° C. for 20 seconds while applying pressure of 140 ° C. and 20 kg / cm ² . For this connection, for example, a known constant heater having a heating head similar to that for temporary connection may be used.

If it fails the visual inspection, the glass substrate 10
Apply 100g of force between the TAB tapes 20 to peel them off.
In this way, the one in the temporarily connected state is peeled off from the glass
The ten board terminal portions 1 are not damaged, and such temporary connection conditions may be experimentally obtained in advance. In addition, after the tape is peeled off, the remains of the conductive film 3 for connection may remain on the substrate terminal portion 1.
It may be removed with methyl ethyl ketone or other suitable solvent. As shown in the figure, the wiped glass substrate 10 returns to the previous step and the steps of temporary connection of the conductive film for connection 3 and the following steps are repeated.

On the other hand, for products that have passed the visual inspection and have been connected, the visual inspection is performed, for example, in the same manner as the visual inspection, and those that have passed are regarded as good products and proceed to the next process, and defective products are discarded.

In the above-described embodiment, first, the case where the conductive film 3 for connection is temporarily connected to the substrate terminal portion of the glass substrate 10, that is, a so-called single supply method is illustrated and described.
It goes without saying that the method of the present invention can be applied in the same manner to the case of the so-called TAB tape reel supply system in which the conductive film 3 for connection is temporarily connected to the tape terminal portion 0 of 0.

FIG. 2 is a diagram showing the relationship between tensile peel strength and heating temperature, where the vertical axis represents tensile peel strength and the horizontal axis represents heating temperature. A known push-pull gauge, for example, was used to measure the tensile peel strength. The sample used and the connection method are the same as those described in detail in the embodiment of FIG.

In the figure, the solid line indicates the case of pulse heater heating with a pressure of 10 kg / cm ² and a heating time of 3 seconds, and the peel strength is 50 g up to about 145 ° C.
It is around, and when it exceeds 150 ℃, some 200g will come out. In the case of this example (thermoplastic anisotropic conductive film), it was confirmed that the peeling strength can be peeled and regenerated up to a tensile peeling strength of about 130 g, and if it is about 50 g or more, it will not easily peel off and it will be There is no hindrance to the work. As a result,
The temporary connection condition may be set to a value such as 140 ° C to 150 ° C, 10 kg / cm ² , and 2 to 3 seconds.

On the other hand, the solid line is pressure 20kg / cm ² , heating time 15 seconds,
The broken line indicates the case of constant heater heating with a pressure of 20 kg / cm ² and a heating time of 25 seconds. In both cases, the tensile peel strength is 300 g or more and the connection strength is extremely high. Therefore, peel regeneration is impossible. Although not shown here, in order to obtain a sufficiently low stable connection resistance, in this example
You can set values such as 140 ℃, 20kg / cm ² , 20 seconds.

As described above, the defect of the liquid crystal display panel due to the TAB tape connection has reached several% in the related art, but in the above-mentioned embodiment, it is greatly improved to about 0%.

In the present embodiment, the case of electrical connection between the electrode terminal row of the terminal portion of the liquid crystal display panel and the electrode terminal row of the TAB tape terminal portion was shown, but the present invention is not limited to this.
It goes without saying that the present invention can also be applied to a method of connecting other products for the same purpose.

Moreover, the above-mentioned temporary connection conditions and main connection conditions are for the conductive film for connection (anisotropic conductive film) used in the examples, and therefore, the present invention is not limited to this and the conductive film for connection used Similarly, the optimum connection conditions may be determined by measuring and evaluating the three types. The conductive film 3 for connection is not limited to the anisotropic conductive film described above, and may be applied to the case of pressure-bonding connection using another conductive film or a connection resin as long as it conforms to the gist of the method of the present invention. Of course.

〔The invention's effect〕

As described above, according to the present invention, the substrate terminal portion 1 on the glass substrate 10 and the tape terminal portion 2 of the TAB tape 20 are
Firstly, the conductive film 3 for connection is sandwiched between them, and then they are aligned and temporarily connected to each other, and an external appearance inspection is performed before the main connection.
If there is any foreign matter 60, or if there is a misalignment, peel off the connection part and reconnect the new TAB tape 20 temporarily in the same procedure, and after passing the appearance inspection, make the final connection, so the final connection failure is large. The production yield of the liquid crystal display panel is greatly improved, and it greatly contributes to the quality improvement and the price reduction of the liquid crystal display device.

[Brief description of drawings]

FIG. 1 is a process diagram showing an embodiment method of the present invention, FIG. 2 is a diagram showing a relationship between tensile peel strength and heating temperature, and FIG. 3 is a diagram showing a connection example of a drive electrode substrate terminal portion and a TAB tape. FIG. 4 is a process drawing showing an example of a conventional TAB tape connection method. In the figure, 1 is a substrate terminal portion, 2 is a tape terminal portion, 3 is a conductive film for connection, 10 is a glass substrate, and 20 is a TAB tape.

Claims (3)

(57) [Claims] 1. A TAB tape for connecting a tape terminal portion (2) of a TAB tape (20) with a conductive film (3) for connection to a substrate terminal portion (1) on a glass substrate (10) of a liquid crystal display panel. In the connection method, the connection conductive film (3) is semi-cured on either one of the substrate terminal portion (1) or the tape terminal portion (2) for temporary connection, and then both terminal portions (1, The connection of (2) and the temporary connection by the semi-curing treatment of the conductive film for connection (3) are performed again, then the connection state of both terminal portions (1, 2) is inspected and confirmed, and then the conductive film for connection. It is characterized in that the main connection state is obtained by treating (3) under curing conditions.
How to connect TAB tape. 2. Alignment of both terminal portions (1, 2),
The alignment mark (41) made of a transparent conductive film provided on the substrate terminal portion (1) and the alignment mark (42) made of a metal conductor provided on the tape terminal portion (2). How to connect the TAB tape described in 1. 3. The method of connecting a TAB tape according to claim 1, wherein the temporary connection conditions are a pressing force of 10 kg / cm ² , a heating time of 2 to 3 seconds, and a heating temperature of 140 to 150 ° C.