JP2760846B2 - Liquid crystal display - Google Patents

Description

The present invention relates to an electrode arrangement of an IC (semiconductor integrated circuit) chip mounted on a TAB (tape automated bonding), a glass substrate, or the like.

[Conventional technology]

An active matrix type liquid crystal display device will be described as an example. A thin film transistor (TFT) is used as a switching element of the liquid crystal display device of this system. A liquid crystal display device using the thin film transistor and the pixel electrode as one component of a pixel has a liquid crystal display panel (LCD) in which a plurality of pixels are arranged in a matrix. Each pixel of the liquid crystal display panel is arranged in a TFT drive wiring, that is, an intersection area between two adjacent scanning signal lines and two adjacent video signal lines. The scanning signal lines extend in the horizontal direction and are arranged in a plurality in the vertical direction. on the other hand,
The video signal lines extend in the vertical direction intersecting with the scanning signal lines, and a plurality of video signal lines are arranged in the horizontal direction.

The liquid crystal display panel has a lower substrate in which a thin film transistor, a transparent pixel electrode, and an alignment film are sequentially provided on a lower transparent glass substrate, and a color filter, a common transparent pixel electrode, an alignment film, and the like are sequentially provided on an upper transparent glass substrate. And an upper substrate, a liquid crystal sealed between the alignment films of both substrates, and a sealing member for the liquid crystal provided at a peripheral portion of the panel. The transparent pixel electrode and the thin film transistor are provided for each pixel.

The liquid crystal display panel includes, for example, a TAB on which an IC chip (drive IC chip) for driving the liquid crystal display panel is mounted, and a printed wiring board (PCB) on which the TAB is mounted. A drive wiring input terminal provided on the periphery of the upper glass substrate (on the lower glass substrate larger in size than the upper glass substrate), and a TA
The output-side outer lead of B is electrically connected by an anisotropic conductive film (a film having a property that current flows in the direction perpendicular to the surface but does not flow in the horizontal direction). Further, the input outer lead of the TAB is electrically and mechanically connected to the output terminal of the PCB which is connected to a signal transmitting means external to the liquid crystal display device by soldering. In addition, drive
The electrodes of the IC chip and the inner leads of the TAB are bonded.

In addition, so-called COG (chip-on-glass) in which the driver IC chip is mounted directly on a glass substrate without using TAB
An implementation has also been proposed.

Note that an active matrix liquid crystal display device using a TFT is, for example, "12.5 type active matrix color liquid crystal display employing a redundant configuration", Nikkei Electronics, pp. 193-210, December 15, 1986, Nikkei McGraw-Hill, Inc. Issued, known in.

FIG. 2 is a plan view of an IC chip showing an example of an arrangement of electrodes (pads) of a conventional IC chip for TAB mounting or COG mounting. 1 is an IC chip, 2a and 2b are output side connection pads (electrodes, hereinafter referred to as output pads) of the IC chip 1, 3a,
Reference numeral 3b denotes an input-side connection pad of the IC chip 1 (hereinafter, referred to as an input pad). The IC chip 1 has an elongated rectangular shape in order to reduce the module size of the liquid crystal display device. The output pads 2a and 2b are on one side of the liquid crystal display panel.
They are arranged along the long side. The output pads 2a,
2b is being n / 2 pieces each staggered arrangement in two rows, which is the output pad number is large and the pitch P ₁ is small, the pads on the glass substrate in the connection and COG to TAB inner lead This is a measure to increase the area of the connection portion so that the wire bonding can be easily performed. 3a, 3b the input signal to the IC1, an input pad for power supply, respectively ₁ m, provided _two m, the pitch is P _2. Therefore, the length y of the long side of the IC chip 1 is about n × P ₁ , and the length x of the short side is about m ₁ × P ₂ or m ₂ × P ₂ , whichever is larger.

[Problems to be solved by the invention]

However, the conventional output pads 2a be used staggered as shown in FIG. 2, the pitch P ₁ of 2b so 70~100μm and narrow, bonding wires comrades short, the bonding wire open failure (bonding wire Cutting,
Peeling), and the probability of occurrence of a defect in the inner lead of the TAB (short circuit between the inner leads, impossible bonding) increases.

An object of the present invention is to provide a pad (electrode) arrangement of an IC chip that enables highly reliable connection.

[Means for solving the problem]

In order to solve the above-mentioned problem, the pad arrangement of the IC chip of the present invention is such that at least one output pad of the rectangular IC chip is provided along two long sides of the IC chip on the surface of the IC chip. It is characterized by being arranged in a column.

Further, the electrode arrangement of the IC chip of the present invention is further described in the above 2nd.
The corresponding pads are connected by wiring on the long sides.

[Action]

The pad arrangement of the IC chip of the present invention is such that the output pad is an IC pad.
Since they are arranged along the two long sides of the chip, the pitch of the output pads can be increased, and a highly reliable connection can be made.

Further, by connecting the corresponding pads on the two long sides by wiring, even if the connection of one of the output pads is cut off, there is no problem, and a highly reliable connection can be made.

Other objects and features of the present invention will become apparent from the following description with reference to the drawings.

〔Example〕

3 (a) to 3 (c) are schematic plan views of an IC chip showing pad arrangement of the IC chip according to the present invention in comparison with the conventional arrangement. (C) in the conventional pad arrangement shown also only along one long side of the IC chip 1 is output pad 2 is provided as shown in Figure 2, smaller pitch P _1, the reliability of the connection descend. In the pad arrangement of the first example of the present invention shown in FIG. 1A, the output pads 2 are provided along the two long sides of the IC chip 1, so that every other output wiring 4 can be connected. And the pitch of the output pad 2 is doubled (2P ₁ )
Can be In the pad arrangement of the second example of the present invention shown in FIG. 2B, output pads are provided on two long sides (one can be used as an inspection pad), and the corresponding output pads on the two long sides are connected to each other. because it is connected by wires (not shown), either no problem if expired one connection of the output pad, the pitch is reduced and P ₁ is a bonding wire or TAB inner lead is open to the output lines 4 This is effective when the connection is easy (this method is called a double-sided lead connection method).

FIG. 1 shows an embodiment of the present invention for mounting TAB or COG.
FIG. 3 is a plan view of the IC chip showing a pad arrangement of the mounting IC chip. 1 is an IC chip, 2a and 2b are output pads of the IC chip 1, 3a and 3b are input pads of the IC chip 1, 5a is an output pad connected to the output pad 2a, and 5b is an output pad
Output pads connected to 2b, 6 are output pads 2a and 5
a, and pad-to-pad connection wiring for connecting 2b and 5b, P ₁ is the pitch of the pitch of the output pads 2a and _{5b, 2P 1 (2 × P} 1) is output pad 2a (or 2b). That is, in this embodiment, the output pads 2a and 2b connected to the even-numbered (or odd-numbered) output wirings (or the inner leads of the TAB) on the substrate to which the output pads of the IC chip are to be connected are the ICs. On the surface of the chip 1, they are alternately arranged in one row along two long sides. The output pads 5a corresponding to the output pads 2a are arranged in a zigzag arrangement with 2b inside 2b along the long side opposite to 2a. The output pads 5b corresponding to the output pads 2b are staggered with 2a inside 2a along the long side opposite to 2b. Output pads corresponding to the two long sides, that is, pads 2a and 5a, and 2b and 5b
Are connected by the wiring 6. Note that the wiring 6 may be formed on the surface of the IC chip 1 or may be formed inside.

FIG. 4 shows an IC chip according to the present invention shown in FIG.
FIG. 7 is a plan view showing a state in which chip bonding (COG mounting) is performed on a lower transparent glass substrate 7 of an active matrix liquid crystal display device using T. Reference numeral 8 denotes an upper transparent glass substrate provided on the lower transparent glass substrate 7. When the method shown in FIG. 3A is used, the pads 2a and 2b of the IC chip shown in FIG.
Connected to. The input pads 3a and 3b in FIG. 1 are connected to the input wirings 9a and 9b in FIG. 4 by wire bonding. Inspection pads 10a and 10b are used to check the connection state and IC failure after the connection between the IC chip 1 and the wiring 4 of the lower transparent glass substrate 7 is completed. Reference numeral 11 denotes an input pad 4a provided on the lower transparent glass substrate 7 (below the IC chip 1) and a test pad 10b, and a wiring for connection between the pads connecting the 4b and 10a, and 12 denotes an outside of the liquid crystal display device. Connected to the input wirings 9a and 9b.

FIGS. 5 (a) and 5 (b) correspond to FIGS. 3 (b) and 1
It is a figure which shows the characteristic of the both-sides lead connection system by the pad arrangement | positioning shown in the figure. (A) is a plan view and (b) is a cross-sectional view. Even if the bonding wire 13a connected to the input pad 4a of the output wiring 4 is broken, there is a bonding wire 13b connected to the pad 10a, so that it is electrically connected to the output stage in the IC through the wiring 6 connecting the pads 2a and 5a. And redundancy can be achieved.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it is needless to say that various changes can be made without departing from the scope of the present invention.

〔The invention's effect〕

As described above, according to the pad arrangement of the IC chip of the present invention, even if the pad interval in the IC becomes narrow, the output wiring can be connected every other line, so that the pitch is doubled and the tolerance is increased, Connection reliability can be improved. Further, by adopting the double-sided lead connection method, a redundant design is possible even in an environment resistant to fear of lead breakage, and connection reliability is improved.

[Brief description of the drawings]

FIG. 1 is a plan view of an IC chip showing one embodiment of a pad arrangement of an IC chip of the present invention, FIG. 2 is a plan view of an IC chip showing one example of a pad arrangement of a conventional IC chip, FIG. (A)
(C) is a plan view of the IC chip showing the pad arrangement of the IC chip according to the present invention in comparison with the conventional method, and FIG. 4 is a chip bonding of the IC chip according to the present invention on a glass substrate of a liquid crystal display device. A plan view showing the situation, FIG. 5 (a),
(B) is a diagram showing the features of the double-sided lead connection system according to the present invention. DESCRIPTION OF SYMBOLS 1 ... IC chip, 2a, 2b ... Output pad 3a, 3b ... Input pad 4 ... Output wiring 5a, 5b ... Output pad 6 ... Wiring for connection between pads 7 ... Lower transparent glass substrate 8 Upper transparent glass substrate 4a, 4b Input pad for output wiring 9a, 9b Input wiring 10a, 10b Pad for inspection 11 Connection wiring between pads on substrate 12 FPC 13a 13b ...... bonding wire n ...... number m ₁ of the output pads, m ₂ ...... pitch P ₂ ...... input pad having P ₁ ...... output pad of the input pads pitch x ...... IC chip short of Side length y ... Length side of IC chip

Claims (2)

(57) [Claims] An upper glass substrate, a lower glass substrate having a size larger than the upper glass substrate, and a liquid crystal sealed and sealed between the two substrates.
A display unit comprising a TFT array; and the TF provided on the lower glass substrate outside the upper glass substrate.
It has a plurality of output wirings to T, and a rectangular IC chip for driving the TFT connected to the output wiring by chip-on-glass mounting, and a plurality of output pads of the IC chip are provided. On the surface of the IC chip, at least one row is arranged along each of two long sides of the IC chip, and output pads electrically connected to one output wiring are divided into a plurality of portions. Liquid crystal display device. 2. An upper glass substrate, a lower glass substrate having a size larger than the upper glass substrate, and a liquid crystal sealed and sealed between the two substrates.
A display unit comprising a TFT array; and the TF provided on the lower glass substrate outside the upper glass substrate.
It has a plurality of output wirings to T, and a rectangular IC chip for driving the TFT connected to the output wiring by chip-on-glass mounting, and a plurality of output pads of the IC chip are provided. Output pads, which are arranged in a plurality of rows in a staggered manner along two long sides of the IC chip on the surface of the IC chip and electrically connected to one output wiring, are divided into respective sides of the two long sides. Wherein the output pads corresponding to each other on the two long sides are connected by IC internal wiring.