JP2995392B2 - Liquid crystal electro-optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrangement of semiconductor elements for driving a liquid crystal electro-optical device.

[0002]

2. Description of the Related Art A liquid crystal electro-optical device has advantages such as light weight and small power consumption as compared with a conventional display element, and is used in various fields, for example, a calculator, a clock, a word processor, a pocket television, and the like. Have been.

[0003] By the way, the arrangement of semiconductor elements for driving liquid crystal in a liquid crystal electro-optical device was initially mainly mounted on a glass epoxy printed board in the form of a package IC. In this case, the connection between the electrode of the printed circuit board on which the package IC is mounted and the electrode formed on the liquid crystal panel is performed, for example, by FPC (Fle
xible Print Circuit).

Recently, TAB (Tape Automated Bond)
ing) method has also been used. This is a method in which a semiconductor chip having bumps formed on a pad portion is subjected to face-down bonding (ILB: Inner Lead Bonding) on a polyimide film on which wiring is formed of Cu or the like, and further formed on the film and a liquid crystal panel. (OLB: Outer Lead Bonding).

There is also a method of directly mounting a semiconductor chip on a substrate constituting a liquid crystal panel. For example, a wiring for inputting a signal to a semiconductor chip and a wiring for supplying an output signal from the semiconductor chip to an electrode of a display portion of the liquid crystal panel are formed on a substrate constituting a liquid crystal panel, and the wiring and the semiconductor are formed. There is also a method of performing wire bonding with a chip using an Au wire, or a method of forming a bump on a pad portion of an IC chip and performing face-down bonding with the wiring.

[0006]

However, among the above methods, a package IC is mounted on a glass epoxy printed board, and the printed board and the liquid crystal panel are connected to each other by FP.
The method of connection using C has a large package IC and arranges it on a heavy glass epoxy printed circuit board, so not only does not take advantage of the “light” of the liquid crystal electro-optical device, but also the printed circuit board and the liquid crystal. Since the FPC is used to connect the panel, the printed circuit board must be connected to the FPC on the one hand, and the liquid crystal panel must be connected to the FPC on the other hand, which requires twice the number of wires to be connected. Therefore, the yield also decreases.

In addition, the TAB method does not require a printed circuit board on which a semiconductor element for driving a liquid crystal is arranged, and
Although the "lightness" is improved, it is not preferable because the polyimide tape becomes very expensive.

When a semiconductor chip is mounted on a substrate on which a liquid crystal panel is mounted, the product of the production yield of the step of connecting the semiconductor chip to the wiring and the yield of the liquid crystal panel itself is the production yield of the entire liquid crystal electro-optical device. Because
The overall production yield significantly decreases, which is not preferable.

[0009]

Means for Solving the Problems In order to solve the above problems, one of the structures disclosed in the present specification includes first and second structures.
Substrate, a plurality of electrodes provided on the inner surface of each of the substrates, a liquid crystal layer disposed between the first and second substrates, and at least one auxiliary substrate, A plurality of circuits each electrically connected to at least one of the electrodes and supplying a drive signal to the one electrode;
The electrical connection is made by an anisotropic conductive adhesive,
The anisotropic conductive adhesive fixes the auxiliary substrate at a predetermined position corresponding to the electrode, and at the same time, the circuit provided on the auxiliary substrate and the one provided on the inside of one of the substrates. At least one of the first and second substrates is connected to the other electrode so as to form an electrical connection between the one electrode and the circuit to provide a terminal for the one electrode to make an electrical connection. A liquid crystal electro-optical device characterized by projecting from an end face of a substrate.

[0010] In another configuration, at least a first and a second glass substrate, an electrode provided on an inner surface of each of the substrates, a liquid crystal layer disposed between the first and the second substrates, A circuit provided on one auxiliary substrate and electrically connected to the electrode to supply a drive signal to the electrode, wherein the electrical connection includes a circuit provided on the auxiliary substrate, A liquid crystal electro-optical device, comprising: an anisotropic conductive adhesive for connecting the electrode provided on one inner side of the substrate.

In another configuration, a first and a second glass substrate, a plurality of electrodes provided on the inner surface of each of the substrates, and a liquid crystal disposed between the first and second substrates are provided. And a semiconductor chip for applying a drive signal to the liquid crystal layer, and at least one glass auxiliary substrate on which electric wiring is formed. The first substrate is provided with a second electrode for providing a terminal of the electrode. Projecting from an end face of the substrate, and the auxiliary substrate is directly attached to the extended portion of the first substrate by an anisotropic conductive adhesive,
The liquid crystal electro-optical device according to claim 1, wherein the electric wiring provided on the auxiliary substrate is electrically connected to the terminal.

In the present invention, the semiconductor chip for driving the liquid crystal of the liquid crystal electro-optical device is mounted on a third substrate different from the first and second pair of substrates constituting the liquid crystal panel. , Wiring on the substrate on which the semiconductor chip is mounted,
The wiring on the substrate constituting the liquid crystal panel is connected.

In the present invention, in order to drive the liquid crystal,
Since a semiconductor chip is used instead of a packaged semiconductor element, a glass-epoxy printed circuit board for mounting the chip is not required. Therefore, the "light" liquid crystal electro-optical device can be used.

Further, in the present invention, since an expensive polyimide tape such as the TAB method is not required, a liquid crystal electro-optical device can be manufactured at low cost.

In the present invention, as a method of connecting the wiring on the substrate on which the semiconductor chip is mounted and the wiring on the substrate constituting the liquid crystal panel, for example, an ultraviolet-curing adhesive mixed with conductive fine particles is applied between the substrates. A method of connecting by irradiating ultraviolet rays while applying pressure, or F
There are a method using PC, a method using anisotropic conductive rubber, and the like. When the FPC is used, it is inevitable that the number of wirings to be connected is twice as large as that described above, but there are advantages of lightness and an increase in yield.

Further, in the present invention, since the substrate constituting the liquid crystal panel and the substrate on which the semiconductor chip is mounted are separately manufactured, after connecting the semiconductor chip to the wiring on the substrate, before connecting to the liquid crystal panel, It is possible to provide a step of performing an electrical test on the connection between the semiconductor chip and the wiring, and as a result, it is not necessary to connect the semiconductor chip to the liquid crystal panel when the connection of the semiconductor chip is not perfect,
Yield increases significantly. Hereinafter, the present invention will be described with reference to examples.

[0017]

【Example】

[Embodiment 1] In this embodiment, the case where wiring on a substrate on which a semiconductor chip is mounted and wiring on a substrate constituting a liquid crystal panel are connected by using conductive fine particles is shown in FIGS. This will be described using (b). FIG. 1A is a schematic diagram of the entire liquid crystal electro-optical device manufactured according to the present embodiment, and FIG. 1B is a connection portion between the liquid crystal panel and a third substrate on which a semiconductor chip for driving a liquid crystal is mounted. It is the schematic of the cross section which shows.

First, a liquid crystal panel is manufactured. First substrate 1
Indium Tin Oxide (ITO) on a 1.1 mm thick soda glass using DC magnetron sputtering method
A film was formed. And using known photolithography
640 stripe-shaped electrodes 9 are formed. And the second
Similarly, as a substrate 2 of IT, an IT
O is deposited to a thickness of 1200 °, and 400 electrodes are produced by photolithography. Thereafter, polyamic acid is applied onto the first and second substrates by using an offset printing method, and heated at 350 ° C. for 3 hours in a clean oven to obtain a polyimide thin film. Then, the surface of the first substrate 1 on which the polyimide thin film was formed was rubbed with a cotton cloth, and then SiO ₂ particles having a diameter of 8 μm were sprayed as spacers. Second substrate 2
An epoxy adhesive was printed on the top using a screen printer. Then, after bonding the first and second substrates,
The liquid crystal was injected by a known vacuum injection method, and the injection port of the liquid crystal was sealed using an ultraviolet curing adhesive. This completes the liquid crystal panel.

Next, the production of the substrate for mounting the IC chip for driving the liquid crystal will be described. The third substrate 3 has a width of 50 mm,
After an ITO film is formed on soda glass having a length of 270 mm and a thickness of 1.1 mm, the wiring 19 is formed by photolithography. Then, Ni plating was performed on the wiring, and Au plating was further performed. The wiring includes a wiring (not shown) for inputting a signal to the semiconductor chip 5 and a wiring for transmitting an output signal from the semiconductor chip 5 to the liquid crystal panel.

Then, a semiconductor chip 5 for driving a liquid crystal having an Au bump formed on the pad portion is connected. In this connection method, an ultraviolet curable adhesive is dropped on a semiconductor chip using a dispensing method, the wiring is aligned with the bump, and then heated to 150 ° C. while applying a pressure of 95 g per bump. For 3 minutes. By this method, a necessary number of semiconductor chips and wirings were connected to both the common electrode side and the data electrode side.

Here, an electrical test was performed on the connection of the semiconductor chips. Then, with respect to all the semiconductor chips arranged on the substrate, the liquid crystal panels are connected only to those that are completely connected. In this embodiment, as the method, first, the conductive fine particles 6 and the conductive fine particles 6 are slightly placed on the wiring formed on the first substrate 4 of the liquid crystal panel which is not overlapped with the second substrate. After applying the ultraviolet curing adhesive 8 mixed with the small fine particles 7 by a dispensing method, the wiring on the liquid crystal panel where the adhesive is applied and the wiring on the substrate on which the semiconductor chip is mounted are overlapped so as to face each other. Ultraviolet rays were irradiated for 3 minutes while applying a pressure of about 2.4 kg / cm ² . The conductive fine particles 6 used here are obtained by subjecting polystyrene particles having a diameter of 7.5 μm to Au plating at 1000 μm. The fine particles 7 slightly smaller than the conductive fine particles 6 are SiO ₂ particles having a diameter of 5 μm. The mixing ratio of the ultraviolet curing adhesive 8, the conductive fine particles 6, and the fine particles 7 is 107: 14: 4 by weight. After this, -30
A heat shock test was carried out at 70 ° C. and 70 ° C. (1 hour each), but no defect was found as in the case immediately after connection.

When connecting the wiring of the liquid crystal panel to the wiring on the substrate on which the semiconductor chip is mounted, it is possible to use only the conductive fine particles.
A more reliable connection can be obtained by using different kinds of fine particles.

The liquid crystal electro-optical device manufactured in this embodiment does not require a glass epoxy printed circuit board because the semiconductor chip is mounted on the glass substrate, and is very light.
Further, since the substrate on which the semiconductor chip is mounted and the substrate constituting the liquid crystal panel are separate, only those in which the semiconductor chip is completely connected can be connected to the liquid crystal panel, thereby significantly increasing the manufacturing yield. .

Further, in this embodiment, since only one connection point is required for connection of one wiring, the process can be simplified and the production yield increases as compared with the case where FPC is used.

[Embodiment 2] When connecting a liquid crystal panel manufactured in exactly the same manner as in Embodiment 1 and a substrate on which a semiconductor chip is mounted, as shown in FIG. 2, the substrate connected to the common electrode side of the liquid crystal panel. And a substrate connected to the data electrode side of the liquid crystal panel at the intersection 10 using an ultraviolet curing adhesive, thereby providing a liquid crystal panel having excellent mechanical strength as compared with the first embodiment. An optical device could be manufactured.

In the present embodiment, what can be bonded at the intersection 10 is that the substrate on the common electrode side of the liquid crystal panel and the substrate on which the semiconductor chip connected to the data electrode side substrate is mounted form the same plane. Further, the data electrode side substrate of the liquid crystal panel and the substrate on which the semiconductor chip connected to the common electrode side substrate is mounted form the same plane.
Therefore, as shown in FIG. 3, one substrate 18 can be bonded so as to straddle one substrate constituting the liquid crystal panel and the substrate on which the semiconductor chip is mounted, thereby further increasing the mechanical strength. be able to.

In FIG. 3, the substrate 18 is shown only between one of the two substrates on which the semiconductor chip is mounted and the substrate 1, but the other substrate and the substrate on which the semiconductor chip is mounted are shown. 2 is provided in the same manner.

Since the substrate 18 is used as a reinforcing material for a connecting portion between the liquid crystal panel and the substrate on which the semiconductor chip is mounted, its material is not particularly specified. It is sufficient that the shape can also serve as a reinforcing material, and there is no particular designation.

[Embodiment 3] This embodiment will be described with reference to FIG. The wiring on the liquid crystal panel manufactured in the same manner as in Example 1 was connected to the wiring on the third substrate on which the semiconductor chip was mounted using the FPC 11. In this method, the electrode 1 on one of the substrates 12 constituting the liquid crystal panel is used.
3 and a Cu wiring 15 formed on the FPC 11 are connected by an anisotropic conductive film 14. When connecting,
A pressure of 30 kg / cm ² was applied at 200 ° C. to perform thermocompression bonding for 8 seconds.
Further, the wiring 16 on the substrate on which the semiconductor chip is
The Cu wiring 15 formed on the PC 11 was similarly connected. In the present embodiment, since the FPC is used, the number of wirings to be connected is twice as large as the number of wirings to be connected.
As in Example 2, a light-weight liquid crystal electro-optical device having a high yield could be manufactured.

[0030]

As described above, by using the present invention, a liquid crystal electro-optical device which is lightweight, inexpensive, and has a high yield can be manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a cross section of an entire liquid crystal electro-optical device according to an embodiment and a connection portion.

FIG. 2 is a diagram schematically illustrating the entire liquid crystal electro-optical device according to the embodiment.

FIG. 3 is a diagram schematically illustrating the entire liquid crystal electro-optical device according to the embodiment.

FIG. 4 is a view schematically showing a cross section of a connection portion of the liquid crystal electro-optical device according to the embodiment.

[Explanation of symbols]

 1, 2, 3 ... substrate 5 ... semiconductor chip 6 ... conductive fine particles 7 ... fine particles 8 ... ······· UV curing adhesive 11 ······· FPC

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/1345 H05K 1/14 H05K 3/36

Claims (6)

(57) [Claims] A liquid crystal is interposed between a first substrate and a second substrate.
In the liquid crystal electro-optical device, the first auxiliary substrate on which the first semiconductor chip and the wiring are arranged
Has a plate, the said first arranged the wiring on the substrate and the first auxiliary group
With the wiring arranged on the board, the conductive fine particles were mixed
The first semiconductor chip is electrically connected by an ultraviolet curable adhesive, and the first semiconductor chip is located outside an end surface of the first substrate.
Placed on the first auxiliary substrate so as to be located on the side
Cage, wherein the first auxiliary substrate is the second substrate and the substantially same Ippei
A liquid crystal electro-optical device characterized by being a plane . A liquid crystal interposed between the first and second substrates.
A liquid crystal electro-optical device, comprising: a first auxiliary substrate on which a first semiconductor chip and a wiring are arranged;
A second auxiliary substrate on which a plate, a second semiconductor chip and wiring are arranged
And a wiring disposed on the first substrate and the first auxiliary substrate.
The wiring arranged on the board is a purple mixed with conductive fine particles.
A wiring , which is electrically connected by an external line curing adhesive and is disposed on the second substrate, and the second auxiliary substrate;
The wiring arranged on the board is a purple mixed with conductive fine particles.
The first semiconductor chip is electrically connected by an external curing adhesive, and the first semiconductor chip is located outside an end surface of the first substrate.
Placed on the first auxiliary substrate so as to be located on the side
And wherein the second semiconductor chip is located outside an end surface of the second substrate.
Placed on the second auxiliary substrate so as to be located on the side
Cage, wherein the first auxiliary substrate is the second substrate and the substantially same Ippei
The second auxiliary substrate is substantially flush with the first substrate.
A liquid crystal electro-optical device characterized by being a plane . 3. The method according to claim 1, wherein the reinforcing material is the first material.
An auxiliary substrate and an outer substrate provided on the outer surface of the second substrate.
The liquid crystal electro-optical device characterized in that it is. 4. The method according to claim 2, wherein the reinforcing material is the first material.
An auxiliary substrate and an outer surface of the second substrate or the second substrate
Provided in contact with the auxiliary substrate and the outer surface of the first substrate.
The liquid crystal electro-optical device, characterized in that it is. 5. The liquid crystal electro-optical device according to claim 1, wherein the first auxiliary substrate has substantially the same thickness as the second substrate. 6. The method according to claim 2, wherein the first auxiliary substrate and the first auxiliary substrate are provided.
And the second auxiliary substrate are the second substrate and
And a liquid crystal electro-optical device having substantially the same thickness as the first substrate .