JPH059957B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a wiring board on which electrical components, etc. are mounted, and particularly relates to a structure of a wiring board that allows testing of a plurality of electrical components, etc., individually after mounting them. .

``Prior Art'' Conventionally, electrical parts and the like are mounted on a board on which electric circuits are drawn, and wiring boards with circuits for driving liquid crystal display devices, image sensors, thermal print heads, and other electronic parts have been used. P-boards were commonly used.

This P-board consists of copper wiring formed on an epoxy or glass epoxy resin substrate by etching, etc., and holes drilled on the copper wiring for inserting the feet of electrical components. The legs were inserted and connected to the electrical circuit by soldering.

In the electric circuit installed on this P board, the common wiring part is almost completed before the electric parts are installed, and after the electric parts are installed in layers, the individual electric parts are tested and the connections with the individual electric parts are completed. I was unable to test the section.

Also, when installing an electric circuit on the P-board and driving a specific electronic component, it is necessary to connect the P-board and the electronic component, so the number of connections increases.
New problems have arisen, such as poor connections.

On the other hand, the electric circuit to which the electrical parts are attached is drawn directly on a part of the board that constitutes the electronic parts such as the image sensor, liquid crystal display device, thermal head, etc., and then the electrical parts are attached. The technique is also known. This method is superior in that the number of parts can be reduced compared to the case where a P board is used, and there is no need for a connection part with the electronic parts to be driven.

However, in this method as well, as in the case of P-boards, after the electrical components are mounted on the electrical circuit on the board, each electrical component is tested to see if it is good or bad, and the connections are tested to see if the connections are good or bad when the electrical components are mounted. I couldn't do the test. Furthermore, in order to connect a plurality of electrical components to a common wiring, multilayer wiring is required, complicating the manufacturing process.

FIG. 2 schematically shows a method for manufacturing the multilayer wiring portion of this conventional device.

As shown in FIG. 2A, a common wiring 15 is formed on the substrate 1 using a conductive material (for example, copper, ITO, etc.) by wet etching or the like.

Next, an insulating film is formed in the pattern shown in Figure B. Here, 16 is the common wiring 15 and the branch wiring 1
This is a contact hole for connection with 7.
As shown in the following figure C, a branched wiring 17 is formed, and electrical components are attached to this branched wiring 17.

In order to connect the branched wiring 17 to the common wiring 15 through the contact hole 16 in such a multilayer wiring part, it is necessary to limit the size of the contact hole 16. However, when the number of terminals of the electrical components to be installed increases, or when the number of electrical components increases, the dimensions of the contact hole 16 must be reduced, and contact failure occurs, especially when using the printing method. Forming an insulating layer has the advantage of reducing costs, but has the technical problem of not being able to form contact holes.

"Structure of the Invention" The present invention relates to a novel structure of a wiring board as described above, and in particular, it is a wiring board having some multilayer wiring components, which improves the problems described above.

In other words, a plurality of common wirings are provided on an insulating board, and the configuration is such that wiring branches from the common wiring and electrical components can be attached to these branched wirings, and each individual component can be inspected after the electrical components are mounted. It is something that can be done.

The present invention will be explained below using drawings showing an example.

FIG. 1 shows an example of the method for manufacturing the novel wiring board of the present invention.

A first wiring group 2 is formed of a conductive material on a substrate 1 having an insulating surface. (Figure A) At this time, the first wiring group 2 is a single wiring group for one electrical component 3 (for example, an IC chip), and the first wiring group 2 is connected to the adjacent electrical component. group 2'
is not connected. If electrical components are attached to the first wiring group 2 in this state, each electrical component can be inspected. If it is defective, it is possible to remove the defective electrical component at this stage, attach a new electrical component, and re-inspect. Next, an interlayer insulating film 4 is formed covering at least a portion of this first wiring group (FIG. 3B). Next, a second wiring group 5 is formed over this insulating film 4 with the same pitch and width as the first wiring group, and the first wiring groups 2 and 2' are interconnected to complete a common wiring group. let In this way, a wiring base having a common wiring group and wiring groups branched from the common wiring group can be constructed.

The present invention does not form a common wiring group, that is, a wiring group to which electrical components are connected, which is formed by interconnecting a plurality of wiring groups, from the beginning. A common wiring group is provided by forming one wiring group, then forming an insulating film on the necessary parts, and finally interconnecting one wiring group for one electric component. In particular, this feature allows inspection of electrical components installed in an electrical circuit one by one.

The present invention will be explained in detail with reference to Examples below.

Example 1 This example shows an example in which the present invention is applied to a liquid crystal display device.

FIG. 3 shows an outline of the method for manufacturing the substrate of this example.

In this example, blue plate glass was used as the substrate 1 used. Since this glass substrate also serves as a cell of a liquid crystal display device as will be described later, highly flat glass was used.

An ITO (indium oxide, tin) conductive film is formed on this glass substrate by a well-known sputtering method, evaporation method, etc., and the ITO film is used as electrodes in a matrix configuration for the liquid crystal display area that occupies most of the substrate 1. 6 was patterned, and a first electrode group 7 constituting a liquid crystal display drive circuit was simultaneously formed on the remaining end of the substrate.

In this example, the electrode 6 and the first electrode group 7 were formed by wet etching.

FIG. 3A shows a schematic diagram of the vicinity of the end of the substrate 1 in this state, and although only two first electrode groups 7 are shown, many more are provided.

At this time, the first wiring group 7 is not yet connected to any other wiring portion and is in an independent state.

Next, a chip 9 of an integrated circuit for driving a liquid crystal display device is directly face-down bonded to the electrical component connecting portion 8 of the first wiring group 7. At this time, the adhesive between the chip 9 and the substrate 1 was cured by using an ultraviolet curing type adhesive at a temperature of 150°C, applying a press pressure of about 3 kg, and irradiating ultraviolet rays with a wavelength of 365 nm for 3 minutes.
This state is shown in FIG. 3B. In this state, the first electrode group 7 is independently provided for one chip 9.

At this time, the independent first electrode group 7 is used as an extraction terminal for inspection to inspect the integrated circuit chip 9 for driving the liquid crystal display device and the face-down bonding connection portion. If it is a good product or the connection part is good, it is good, but if it is a defective product or the connection part is defective, the chip 9 that has been bonded once is removed, another chip is attached, and the test is performed again.

By doing so, it was possible to improve the manufacturing yield of the liquid crystal display device.

Next, the interlayer insulating film 10 of the multilayer wiring portion was formed in the necessary portions by screen printing. The material used was epoxy resin, which was printed to a thickness of 40 to 50 μm in the shape shown in FIG. 3C, and baked at 180° C. for 30 minutes.

By using the shape of the interlayer insulating film of the multilayer interconnection part as in this embodiment, there is no contact hole, so it is possible to have a large margin during printing.

Further, the pattern of this interlayer insulating film may have the shapes shown in FIGS. 4A to 4C.

In other words, it is sufficient that the interlayer insulating film is provided in the minimum required portion.

Further, after the step of forming the interlayer insulating film is completed, the step of mounting the integrated circuit chip 9 and the step of inspecting it may be performed.

Next, the independent first
A second wiring group 11 connected to the wiring group 7 is formed, and the first wiring group 7 is connected to each other to form a common wiring. This situation is shown in FIG. 3D.

This second wiring group 11 is made by printing copper paste according to the pattern by screen printing method, and then
It was formed by baking at 180°C for 20 minutes.

Furthermore, a protective film was formed on the entire surface near the edges of these substrates.

In this way, it was possible to complete a wiring board having an electrical circuit on a glass substrate and having electrical components mounted thereon.

The other substrate is manufactured using almost the same process as this substrate, and after both substrates are subjected to the necessary processing for a liquid crystal display device, the two substrates 1 are stacked, and a spacer is inserted between them to keep the gap distance constant. The outer periphery was sealed to complete the liquid crystal cell, and liquid crystal material was injected into the space to complete the liquid crystal display device.

In this embodiment, the patterning of the electrode 6 on the substrate 1 of the liquid crystal display device may be performed by a conventionally known etching method, but the patent application filed by the present applicant in 1983-
Patterning may be performed using an excimer laser as described in No. 18602.

In this case, since a wet process is not used, the process cost and material cost can be reduced.

Further, in this case, the first wiring group 7 may also be formed by a printing method like the second wiring group 11.

Example 2 This example describes a case where the configuration of the present invention is applied to an image sensor.

A first conductive film 12 patterned in a predetermined manner on a substrate 1, a semiconductor layer 13 for photoelectric conversion, and a second conductive film 14 are formed on the substrate 1 of a sensor array using a conventionally known technique. An electric circuit for driving the sensor array is provided near the end. For this purpose, a pattern of the first wiring group is formed using copper paste by a screen printing method.

At this time, the first wiring group 7 and the first wiring group 7 of the sensor array
The conductive film or the second conductive film is aligned and partially connected.

Next, this printed board is baked to harden the copper paste and form wiring. The temperature at this time is preferably 200° C. or lower to the extent that the material used in the sensor is not affected.

Next, after forming an interlayer insulating film 10 covering at least a portion of this first wiring group 7 in the same manner as in Example 1, an IC 9 for driving an image sensor is face-down bonded to the first wiring group 7. The IC 9 and the connection portion between the IC 9 and the first wiring group 7 were inspected.

At this time, the connection between the IC chip 9 and the substrate 1 was temporarily bonded, and the IC was inspected and if there were no defects, the bonding was completed. If there were any defects, the IC chip 9 was removed and the connection was made again to achieve complete bonding. .

By doing this, it is possible to eliminate the possibility of accidental removal of the first wiring group at the same time when removing a defective IC chip, and it is possible to further improve manufacturing yield. Summer.

Thereafter, printing of a second wiring group, printing of a protective film, etc. were performed under the same conditions as in Example 1 to complete an image sensor.

It goes without saying that the present invention can be widely applied to other electrical and electronic components, but as shown in Examples 1 and 2 above, COG (chip-on-glass),
Applying technology such as COB (chip on board) to the mounting of IC chips directly on a substrate has made it possible to achieve remarkable effects in reducing manufacturing costs and manufacturing processes.

〔effect〕

By having the configuration of the present invention, it is possible to inspect the electrical components installed in the electrical circuit before the manufacturing is completed, which was impossible in the past, and determine whether the components are good or defective, thereby improving the yield of the product. I was able to improve it significantly.

Also, is it possible to completely eliminate contact holes that connect common wiring and branch wiring?
Since the size can be increased, there is a margin for alignment accuracy in the manufacturing process.

Furthermore, since there is a margin in the alignment accuracy of the wiring, all wiring can be done by screen printing, making it possible to significantly reduce the manufacturing cost.

[Brief explanation of drawings]

FIGS. 1 and 3 schematically show the manufacturing process of the present invention. Figure 2 shows the multilayer wiring section of a conventional wiring board. FIG. 4 shows an example of the pattern of the interlayer insulating film of the present invention. 1... Board, 2, 7... First wiring group, 5, 1
DESCRIPTION OF SYMBOLS 1... Second wiring group, 10... Interlayer insulating film, 9...
...IC chip.

Claims (1)

[Claims] 1. A step of forming a plurality of first wirings for supplying input signals to a plurality of electrical components on a substrate having an insulating surface, and forming an insulating layer covering at least a portion of the first wirings. forming a common wiring by forming a plurality of second wirings on and extending from the insulating layer and electrically connecting to the first wiring; 2. Wiring on an insulating substrate characterized by having a step of mounting an electrical component on a predetermined position on the substrate and inspecting the electrical component or the connection part of the electrical component before forming the second wiring and completing the common wiring. Formation method. 2. The method for forming wiring on an insulating substrate according to claim 1, wherein the first wiring, the second wiring, and the insulating layer are all formed by a printing method. 3. In claim 1, the first wiring is formed by a method using photolithography, and the second wiring and the insulating layer are formed by printing, on an insulating substrate. Wiring formation method. 4. A step of forming a plurality of first wirings for providing input signals to a plurality of electrical components on a substrate having an insulating surface, and a step of forming an insulating layer covering at least a portion of the first wirings, forming a plurality of second wirings on and extending from the insulating layer, and forming a common wiring by electrically connecting with the first wiring; Before forming the wiring and completing the common wiring, there are two steps: temporarily fixing the electrical components in a predetermined position on the board, inspecting the electrical components or the connections of the electrical components, and completely mounting the electrical components. A method for forming wiring on an insulating substrate, comprising: 5. The method for forming wiring on an insulating substrate according to claim 4, wherein the first wiring, the second wiring, and the insulating layer are all formed by a printing method. 6. The insulating material according to claim 4, wherein the first wiring is formed by a method using photolithography, and the second wiring and the insulating layer are formed by a printing method. A method of forming wiring on a board.