JPH03204946A - Substrate connected with ic - Google Patents

Abstract

PURPOSE:To avoid the grade crossing of wirings formed on a substrate by a method wherein out of the input terminals of a plurality of ICs, at least one kind of the terminals for inputting a common input signal are electrically connected in series by the wirings. CONSTITUTION:In ICs, gold bumps are respectively formed at terminal parts, input terminals 12 and 13, 14 and 16, 16 and 17 and 18 and 19 are electrically short-circuited from each other and the terminals other than the terminal 12 or terminals 20 are described as ones which are not terminals for inputting a common signal. The connection method of the ICs with a substrate is performed by a method wherein an ultraviolet curing resin is put on the ICs and after the substrate and the ICs are aligned to each other, the substrate and the ICs are subjected to pressure bonding to each other in a state that they are heated at about 100 deg.C and an ultraviolet irradiation is performed. Wirings 50 are formed and moreover, all the common signal input terminals, which are connected by means of a cascade connection excluding the terminals 20, of the ICs are electrically connected in series. Therefore, there is no need to provide the wirings 50 in a grade crossing and the yield of the formation of the wirings is also significantly risen.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a substrate on which an IC such as a liquid crystal display device or an image sensor is directly mounted.

[Conventional technology]

Driver I for liquid crystal electro-optical devices, image sensors, etc.
Conventionally, C is mounted on a printed circuit board in a packaged state, and connected to a liquid crystal panel or an image sensor main body using an FPC or the like. However, recently, in order to avoid the use of heavy printed circuit boards and to make devices lighter and smaller, methods have been developed in which IC chips are directly mounted on substrates that make up liquid crystal panels, image sensors, etc.
There are also other names such as OG (chip on glass) and COB (chip on board).

Methods for directly mounting an IC chip on a substrate include face-up bonding, in which the input and output terminals of the IC chip face upward, and face-down bonding, in which the input and output terminals of the IC chip face downward. In the case of face-up bonding, the terminals of the IC and the wiring formed on the substrate are usually connected by wire bonding using thin gold wires. In addition, in the case of face-down bonding, a convex bump made of gold or solder is formed on the wiring formed on the board or the terminal part of the IC, and the IC
Electrical connection is being made between the cable and the wiring.

[Problems with conventional technology]

However, when connecting the input/output terminals of the IC and the wiring formed on the substrate by wire bonding, it is obvious that the connection between the IC terminal and the wiring must be made one by one.

Therefore, as the number of terminals on an IC increases, the number of gold wires also increases, which takes a very long time to connect one IC, leading to an increase in production costs. Furthermore, in this method, there are two connection points for each wire: the wiring on the board and the gold wire, and the gold wire and the IC terminal, resulting in poor yield.

In addition, when using the face-down bonding method, since one IC can be connected in one process, it has the advantage that the time required for the process does not change even if the number of IC terminals increases. . However, multiple ICs used in liquid crystal electro-optical devices, image sensors, etc.
When mounted on a board, a cascade connection is performed, and among the input terminals of the plurality of ICs, at least one type of terminal that inputs a common signal is electrically connected in parallel. To explain this using Figure 2,
Wiring (23) and I for inputting common signals to IC
Terminals (26) and (29) of C(21) and (22)
), similarly wire (24) and terminal (27), (30
), the wiring (24) and the terminal (27) to connect the wiring (25) and the terminals (28) and (31), respectively.
, (30), the wiring (23) gets in the way and requires a three-dimensional wiring part (100).

Furthermore, the wiring (23) and (24) get in the way of connecting the wiring (25) and the terminals (28) and (31), requiring three-dimensional wiring. In addition, as a result of three-dimensional wiring, terminals (26), (29), and (27) for manually inputting common signals were installed.
(30), (2nd), and (31) are electrically connected in parallel.

Furthermore, since photolithography or printing methods are usually used to form wiring, the yield is severely reduced when three-dimensional wiring is produced, and the overall device becomes expensive. In addition, an insulating layer is always required for three-dimensional wiring, and a contact hole must be provided by etching a portion of the insulating layer. For this reason, advanced technology and complicated manufacturing processes were required.

[Purpose of the invention]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to avoid three-dimensional intersections of wiring formed on a substrate when a plurality of ICs are connected in cascade to the wiring formed on the substrate.

[Structure of the invention]

In order to achieve the above object, the present invention provides a substrate on which a plurality of wirings are formed and a plurality of ICs are cascade-connected to the wirings, wherein a common input signal is input from input terminals of the plurality of ICs. At least one type of terminal is electrically connected in series by the wiring.

In order to realize the configuration of the present invention, for example, there is a method using an IC that has two terminals for inputting a common signal and the two terminals are electrically short-circuited, or a method in which the input terminal is connected to the board. IC arranged at a certain angle with the formed wiring
A method using an IC that has at least a part of the peripheral part of the IC without input/output terminals,
Alternatively, there are many methods such as using an IC having a terminal interval larger than the width of the wiring formed on the substrate. Hereinafter, the present invention will be explained in detail with reference to Examples.

[Example 1] In this example, a case where a liquid crystal electro-optical device having an IC mounted on a substrate is manufactured will be explained using FIG. 1. first,
1,500 ITO films, which are transparent conductive films, are deposited on a pair of soda glass substrates (1) and (2), and electrodes (3) are formed by photolithography. Then, gold plating (4) was performed only on the ITO electrodes around the substrate. Then, a polyimide film (5) is formed as a liquid crystal alignment film by an offset printing method. The method for forming this alignment film is to apply an NMP solution of polyamic acid onto the substrate, and then
It was obtained by heat treatment at 250°C for 3 hours.

Next, a rubbing process is performed on the alignment film forming surfaces of the pair of substrates. Then, polystyrene particles (6) having a diameter of 5.5 μm were scattered on one of the substrates. This spraying method uses 30 mg of polystyrene particles with IPA (isopropyl alcohol).
0.51! , and after applying ultrasonic waves and stirring well, spraying was performed using a nozzle. Furthermore, an epoxy adhesive (7) was printed on the other substrate by a screen printing method, and the pair of substrates were bonded together.

A nematic liquid crystal (80%
) was injected, and the injection port was sealed using ultraviolet curing resin.

Then, polarizing plates (9) and (10) were attached to the outside of the substrate.

After that, on the gold-plated wiring formed around the substrate, 6 IC0Is are placed on the scanning electrode side and 8 IC0Is are placed on the signal electrode side.
) was cascaded. The appearance of the gold-plated wiring section is as shown in Fig. 3. Furthermore, the IC uses an IC with gold bumps formed on the terminal section, and input terminals 02) and (13) in Fig. 3 are used. , (lJ (15)
, QE) GQ7), 08) G09) Ha? ! An IC that is mechanically shorted is used. Furthermore, in FIG. 3, among the terminals shown in the figure, the terminals other than the terminals 021 to QΦ are not terminals for inputting common signals.

In addition, the connection method is to place ultraviolet curing resin on the IC (the surface where the terminal is present), and after aligning the board and IC,
A method was used in which the substrate and IC were pressed together while heated to 0° C., and then irradiated with ultraviolet rays. After all the ICs were connected, they were connected to the drive circuit, and the liquid crystal electro-optical device was completed.

In this embodiment, as shown in FIG.
, and as mentioned earlier input terminals 021 and 0
3), 04) and planes are electrically shorted, so all cascade-connected ICs except C'l)
The common signal input terminals of are electrically connected in series.

Therefore, the wiring shown in FIG. 3 does not need to have three-dimensional intersections, which greatly increases the yield.

[Embodiment 2] In this embodiment, a case where the present invention is applied to an image sensor will be described.

A part of the sensor is manufactured by forming a light shielding layer, a photoelectric conversion layer, and an electrode on a glass substrate. At this time, the electrode is formed not only as a part of the sensor but also as a wiring for connecting the IC.

All the wiring in the portion to which the IC is connected is formed of the constituent material of the electrode.

Thereafter, the IC and wiring were connected in the same manner as in Example 1 using an IC having gold bumps in the terminal portion. However, in this embodiment, the heating temperature when connecting the IC is 150°C.

In this state, the state of the part where the IC is connected is shown in the fourth section.
As shown in the figure. The IC used in this example has terminals (32) and (3).
Since the arrangement direction of (3) and (34) is deviated by an angle of θ from the direction of the wiring (35) on the board, (32), (
33) and (34) are electrically connected in series for all ICs, eliminating the need for three-dimensional crossing of the wiring (35) formed on the substrate. However, among the terminals shown in Fig. 4, (32), (33), (
It is assumed that terminals other than 34) are not terminals for inputting common signals.

[Example 3] Terminal arrangement as shown in Fig. 5 ((36), (37)
, (38) is a common signal input terminal) was used in the image sensor of Example 2. In this case, I.C.
common signal input wiring (40
) is shown in Figure 5, and (3
6), (37), and (38) are electrically connected in series for all ICs, so it was possible to avoid three-dimensional crossing of wiring.

(Effects) As described above, when multiple ICs are cascade-connected on wiring formed on a substrate by using the present invention, wiring for supplying common signals input to multiple ICs is There is no need for three-dimensional intersection, the yield of the COO or COB method can be significantly improved, and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 schematically shows a cross section of a liquid crystal electro-optical device. FIG. 2 shows a conventional connection between wiring formed on a substrate and terminals of an IC. FIGS. 3, 4, and 5 show how wiring formed on a substrate and terminals of an IC are connected according to the present invention.

Claims (1)

[Claims] 1. A board on which a plurality of wirings are formed and a plurality of ICs are cascade-connected to the wirings, and among the input terminals of the plurality of ICs, at least one type of terminal inputting a common input signal is A board to which an IC is connected, characterized by being electrically connected in series by wiring.