JP2602237B2 - Liquid crystal display - Google Patents

Description

The present invention is effective when applied to a wiring technique of a liquid crystal display device, particularly to a wiring technique using a flexible wiring board on which a plurality of terminals are arranged. Technology.

[Conventional technology]

A tape carrier type semiconductor device is used for driving the liquid crystal display device. Tape carrier type semiconductor devices
It is characterized in that it can be made thinner and is suitable for mass production.

The tape carrier type semiconductor device is configured by connecting external terminals (bonding pads) of a semiconductor element to a plurality of internal terminals arranged on the surface of a film substrate (wiring substrate) with a protruding electrode interposed therebetween.

The film substrate is formed in a tape shape, and is configured to have flexibility using an epoxy resin material.

The internal terminals of the film substrate, with wiring interposed,
It is connected to an external terminal connected to a liquid crystal display panel or another external device. The external terminals of this film substrate are
In order to increase the number of pins, a plurality of pins are regularly arranged in a fine size. The external terminals, internal terminals, and wiring of the film substrate are configured by sequentially stacking a copper (Cu) layer, a nickel (Ni) layer, and a gold (Au) layer with an adhesive layer formed of epoxy resin interposed therebetween. .

The external terminals of the film substrate and the liquid crystal display panel or other external devices are connected by thermocompression bonding with conductive rubber containing metal particles interposed in an insulating resin tape.
In this thermocompression bonding, a plurality of external terminals and a liquid crystal display panel or other external devices are connected together by a bonding tool.

In addition, regarding the tape carrier type semiconductor device, for example, Nikkei McGraw-Hill Company, Nikkei Electronics, 1985
December 2, 2002, p291.

The applicant has investigated and found Japanese Utility Model Application Laid-Open No. 62-80368.In Japanese Utility Model Application Laid-Open No. 62-80368, there is a description of mounting an LSI chip on a flexible printed circuit board provided with dummy terminals. There is no disclosure of a configuration in which a flexible printed circuit board is connected to an external device other than a liquid crystal panel, a configuration of an internal terminal that is not connected to an external terminal, and a configuration in which an external terminal is commonly connected.

[Problems to be solved by the invention]

The present inventor has discovered that a connection failure frequently occurs at a connection portion between the tape carrier type semiconductor device and a liquid crystal display panel or another external device. In particular, among the plurality of external terminals arranged on the film substrate, peeling frequently occurs at the outermost terminal. For this reason, there is a problem that the electrical reliability of the liquid crystal display device using the tape carrier type semiconductor device is reduced.

The present inventor considers that the end portion of the bonding tool that performs thermocompression bonding is easily cooled, so that the connection where the outermost terminal on the outermost end is arranged is not sufficiently performed, and connection failure occurs at that portion. I have.

In addition, the present inventor, because the film substrate is formed of a resin material, is easily deformed by thermocompression bonding (is easily warped), and the end of the film substrate, that is, the portion where the outermost terminals are arranged, is deformed. It is considered that since a large stress is generated, a connection failure occurs at that portion. In particular, since the external terminals of the film substrate are regularly arranged at high density with a fine size in order to increase the number of pins, a sufficient bonding area cannot be secured.

An object of the present invention is to provide a technique capable of improving the electrical reliability of a device using a flexible wiring board.

Another object of the present invention is to provide a technique capable of improving the connection strength between an external terminal of a flexible wiring board and an external device.

Another object of the present invention is to provide a technique capable of improving the connection strength between an external terminal electrically connected to a semiconductor element via an internal terminal and a liquid crystal display panel or an external device.

It is another object of the present invention to provide a technique capable of improving the connection strength between an external terminal of a flexible wiring board and an external device and increasing the number of pins of the wiring board.

The above and other objects and novel features of the present invention are as follows.
It will be apparent from the description of this specification and the additional drawings.

[Means for solving the problem]

The outline of a typical invention disclosed in the present application is briefly described as follows.

Of the plurality of external terminals arranged on the flexible wiring board, the terminal arranged at the extreme end or the external terminal arranged near the extreme end is configured as an external terminal that is not electrically connected to the internal terminal. Alternatively, the external terminals are commonly connected and configured with a larger area than the other external terminals, or configured as dummy terminals.

Further, among the external terminals to which a power supply and a signal are applied on the flexible wiring board, a terminal outside the external terminal connected to the external device and a terminal outside the external terminal connected to the liquid crystal display panel are used. Connect to the internal terminals by connecting the power supply and the signal to the liquid crystal display panel on the flexible wiring board without using the semiconductor elements on the flexible wiring board without connecting to the internal terminals. An external terminal that is not provided is provided outside the external terminal connected to the internal terminal.

[Action]

According to the above-described means, by providing the terminal outside the external terminal electrically connected to the internal terminal, the connection strength of the external terminal electrically connected to the internal terminal can be improved.

Further, the bonding area of the terminal disposed at or near the outermost end of the wiring board can be increased and the connection strength can be improved, so that connection failure can be reduced. Also,
In the case of a dummy terminal, since it has no function electrically, it does not cause a connection failure even if it is peeled off.

Further, since the area of the terminals other than the terminal arranged at or near the outermost end can be reduced, the number of pins of the wiring board can be increased.

Hereinafter, the configuration of the present invention will be described together with an embodiment in which the present invention is applied to a wiring board of a tape carrier type semiconductor device.

In all the drawings for describing the embodiments, components having the same function are denoted by the same reference numerals, and their repeated description will be omitted.

〔Example〕

(Example I) Example I is a first example of the present invention in which the present invention is applied to a tape carrier type semiconductor device used for driving a liquid crystal display device.

FIG. 2 (plan view) shows a schematic configuration of a liquid crystal display device which is Embodiment I of the present invention. FIG. 1 (enlarged plan view) and FIG. (A cross-sectional view taken along the line III-III in the figure).

The liquid crystal display device has a TF as shown in FIGS. 2 and 3.
At the center of the T liquid crystal panel 11, a display unit 12 in which display elements are arranged in a matrix is provided. TFT LCD panel 1
1 is formed of a transparent glass substrate 11A. Each display element of the display unit 12 mainly includes a pixel electrode for each element, a common pixel electrode common to each element, a liquid crystal LC sealed between the two electrodes, and a thin film transistor (TFT) for selecting the pixel electrode. Have been.

The display section 12 has a terminal 1 on the periphery of the TFT liquid crystal panel 11.
It is driven by the tape carrier type semiconductor device 1 connected via the intermediary 3.

As shown in detail in FIGS. 1 and 3, the tape carrier type semiconductor device 1 has internal terminals (inner terminals) 14 of the wiring pattern 3 formed on the surface of the base film substrate 2.
A, a protruding electrode (bump electrode) 4 is interposed therebetween, and an external terminal (boding pad) of a semiconductor element (semiconductor chip) 5
Are connected.

The base film substrate 2 is formed of a flexible resin material (for example, an epoxy resin material). The base film substrate 2 is obtained by previously cutting a tape-shaped substrate into a predetermined size.

The wiring pattern 3 is provided on the surface of the base film substrate 2 with an adhesive layer (not shown) interposed. The adhesive layer is formed to enhance the adhesiveness between the wiring pattern 3 and the base film substrate 2, and is formed of, for example, an epoxy resin material whose surface is activated by oxygen (O ₂ ) plasma. The adhesive layer may not necessarily be provided when the adhesiveness between the base film substrate 2 and the wiring pattern 3 is good.

External terminals 14B and 14C connected to the terminals 13 of the liquid crystal display panel are provided on the surface of the base film substrate 2 (left side in FIG. 1).
And other external devices such as external terminals 14G and 14H (right side in FIG. 1) connected to a printed wiring board. External terminals 14B and 14C, 14G and 14H are connected to base film substrate 2
Are regularly arranged at high density along the opposing left and right sides.

On the surface of the base film substrate 2, there are provided internal terminals 14A.
A wiring 3A connecting the internal terminal 14A to the external terminal 14G, a wiring 3C connecting the external terminals 14C and 14H, and a wiring 3C not connected to the internal terminal 14A. ing.

Further, the external terminals 14C arranged outside one end of the plural external terminals 14B arranged along one side of the base film substrate 2 have a larger area than the external terminals 14B,
The external terminal 14H disposed outside the end of the external terminal 14G has a larger area than the external terminal 14G.

A signal or power is applied to the external terminal 14B, and similarly, a signal or power is applied to the external terminal 14C. A signal or power is applied to the external terminal 14G.
Signals and power are applied to 4H.

The connection between each of the external terminals 14B and 14C of the base film substrate 2 and the terminal 13 of the liquid crystal display panel, that is, the mounting of the tape carrier type semiconductor device 1 is performed by the bonding layer 8 shown in FIG.
And a bonding tool 9 indicated by a dotted line. This connection or mounting is performed collectively by thermocompression (heating and pressing) (a plurality of outer ends 14B and 14C
In a single thermocompression bonding). The adhesive layer 8 is made of, for example, conductive rubber, that is, an insulating resin tape containing metal particles.

Wiring pattern 3 and internal terminal of base film substrate 2
The 14A and the external terminals 14B, 14C, 14G, and 14H are formed by, for example, sequentially electroplating a nickel (Ni) layer and a gold (Au) layer on a patterned copper (Cu) foil.

As described above, the external terminals 14C and 14H are provided outside the outermost ends of the plurality of external terminals 14B and 14G arranged on the flexible base film substrate 2, respectively, and the external terminals 14C and 14H are connected to the internal terminals 14A. By not doing so, the connection strength of the external terminals 14B and 14G connected to the internal terminals can be improved.

Also, by configuring the external terminal 14C with a larger area than the external terminal 14B and configuring the external terminal 14H with a larger area than the external terminal 14G, the bonding area of the outermost external terminals 14C and 14H can be increased. Since the connection strength can be improved, the connection failure can be reduced. As a result, when the thermocompression bonding is performed, even if the end of the bonding tool 9 is cooled, the connection portions of the external terminals 14B and 14G are not easily peeled off.
As a result, the base film substrate 2
Even when the external terminals 14B and 14G are deformed and a large stress is generated at the ends thereof, the connecting portions of the external terminals 14B and 14G are hardly peeled off.

Also, by reducing the area of the external terminals 14B and 14G, the distance between the external terminals 14B and 14G is reduced, and the external terminals
Since 14B and 14G can be arranged at high density, the number of pins of the base film substrate 2 can be increased.

Semiconductor element 5 mounted on base film substrate 2
The connection between the wiring pattern 3 and the semiconductor element 5 is sealed with a resin material 6. The resin material 6 is formed of an organic resin material such as an epoxy resin.

A predetermined portion of the base film substrate 2 is provided with a positioning hole 7 for attaching to the TFT liquid crystal panel 11. The positioning hole 7 includes a base hole 7a formed in the base film substrate 2 and a conductor hole 7b formed of the same conductive layer as the wiring pattern 3.

(Embodiment II) The present embodiment II is a tape carrier type semiconductor device according to the present invention, in which a plurality of terminals arranged near the end or at the vicinity of the end are connected in common to form a terminal having a large area. This is a second embodiment of the present invention.

FIG. 4 (enlarged plan view) shows a tape carrier type semiconductor device for driving a liquid crystal display device which is Embodiment II of the present invention.

As shown in FIG. 4, the tape carrier type semiconductor device 1
The external terminal 14C having a larger area than the external terminal 14B or the external terminal 14H having a larger area than the external terminal 14B is connected in common to a plurality of external terminals arranged near the outermost end or the outermost end. (A plurality of external terminals surrounded by a dotted line).

Each of the external terminals constituting the external terminals 14C and 14H has substantially the same size as or a slightly different size from the external terminals 14B and 14G.

The external terminals 14B and 14G are connected to the internal terminal 14A via wirings 3A and 3B, respectively, and the external terminals 14C and 14H are connected to the internal terminal 14A via the wiring 3C without being connected to the internal terminal 14A.

The base film substrate 2 configured as described above can obtain substantially the same effects as those of the first embodiment.

(Example III) In Example III, in the tape carrier type semiconductor device, a terminal arranged outside or near the external terminal 14C or 14H was configured as a dummy terminal 14I. It is a third embodiment of the present invention.

FIG. 5 (enlarged plan view) shows a tape carrier type semiconductor device for driving a liquid crystal display device which is Embodiment III of the present invention.

As shown in FIG. 5, the tape carrier type semiconductor device 1
Is an external terminal located near the external terminal 14C or 14H
14I is configured as a dummy terminal that is not electrically connected to the semiconductor element 5 or the liquid crystal display device 11 (has no electrical function). The external terminal 14I has substantially the same size, a slightly larger size, or a slightly smaller size as the external terminal 14B or 14G.

The external terminals 14B and 14G are connected to the internal terminal 14A via wirings 3A and 3B, respectively, and the external terminals 14C and 14H are configured via the wiring 3C without being connected to the internal terminal 14A.

In the base film substrate 2 configured as described above, since the dummy terminals do not have an electrical function, even if the dummy terminals are separated, no connection failure occurs, and substantially the same effects as those of the embodiment I can be obtained. .

As described above, the invention made by the inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and can be variously modified without departing from the gist thereof. Of course.

For example, the present invention is not limited to a base film substrate of a tape carrier type semiconductor device, but can be applied to a flexible printed wiring board on which a plurality of semiconductor devices can be mounted.

The liquid crystal display element has been described as a TFT liquid crystal display element, but it is needless to say that the present invention can be applied to a simple matrix type liquid crystal display element.

〔The invention's effect〕

The effects obtained by the representative inventions among the inventions disclosed in the present application will be briefly described as follows.

Reduces connection failure of terminals on flexible wiring boards,
It is possible to improve electrical reliability and increase the number of pins of the wiring board.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view of a tape carrier type semiconductor device for driving a liquid crystal display device which is Embodiment I of the present invention. FIG. 2 is a plan view showing a schematic configuration of the liquid crystal display device. FIG. 4 is a sectional view taken along the line III-III in FIG. 2, FIG. 4 is an enlarged plan view of a tape carrier type semiconductor device for driving a liquid crystal display device which is Embodiment II of the present invention, FIG. FIG. 5 is an enlarged plan view of a tape carrier type semiconductor device for driving a liquid crystal display device according to Embodiment III of the present invention. In the figure, 1 ... tape carrier type semiconductor device, 2 ... base film substrate, 3A, 3B, 3C ... wiring pattern, 5 ... semiconductor element, 9 ... adhesive layer, 11 ... TFT liquid crystal panel, 14A ...
... internal terminals, 14B, 14C, 14G, 14H ... external terminals.

Claims (6)

(57) [Claims] 1. A liquid crystal display device comprising: a liquid crystal panel; a flexible wiring board on which a semiconductor element for driving the liquid crystal panel is mounted; and an external device connected to the wiring board. The substrate includes a plurality of first external terminals connected to the liquid crystal panel on one of two opposing sides;
A plurality of second external terminals connected to the external device, an internal terminal electrically connected to the semiconductor element, the first external terminal and the upper internal terminal are connected to the other of the two opposing sides. A first wiring, a second wiring connecting the second external terminal and the internal terminal, and a terminal outside the first external terminal and a terminal outside the second external terminal. A liquid crystal display device having a third wiring connected without interposition, wherein the third wiring supplies an arbitrary voltage of the external device to the liquid crystal panel. 2. The liquid crystal display device according to claim 1, wherein the connection between the first substrate and the liquid crystal display panel is made by an adhesive containing conductive particles. 3. The liquid crystal display according to claim 1, wherein an area of said first external terminal connected to said third wiring is larger than other first external terminals. apparatus. 4. The liquid crystal display according to claim 1, wherein an area of said second external terminal connected to said third wiring is larger than other second external terminals. apparatus. 5. The liquid crystal display device according to claim 1, wherein a dummy terminal is provided alongside said first external terminal connected to said third wiring. 6. The liquid crystal display device according to claim 1, wherein a dummy terminal is provided alongside said second external terminal connected to said third wiring.