JP2001332202A - Chip-on-glass fluorescent display tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm the state of conductive connection between terminal portions of semiconductor elements for driving and a wiring on a substrate through observing from exterior of the substrate. SOLUTION: The COG fluorescent display tube is subjected to conductive connection in exterior of an airtight envelope 11 on a translucent substrate 1, forming a part of the airtight envelope 11 by means of anisotropic conductive materials 13, dispersed uniformly with electroconductive particles in an adhesive between wiring conductors 4 wired, by extending outward from the airtight envelope 11 and a semiconductor element 12 having a metal vamp 12a at the bottom face. Formed on the semiconductor element 12 is a dummy bump 12b, facing which frame-shaped window-cut patterns 15 are formed on the substrate 1. After connecting with the anisotropic conductive materials 13, state of conductive connection between each metal bump 12a of the semiconductor elements 12 and the wiring conductors 4 is confirmed by observing collapsed state of electroconductive particles 13b of the anisotropic conductive materials 13 through its window portion from exterior of the substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor for driving a wiring formed on a light-transmitting substrate forming a part of a hermetic envelope and extending from the inside of the hermetic envelope to the outside. The present invention relates to a chip-on-glass fluorescent display tube in which an element (IC chip) is electrically connected outside the hermetic envelope.

[0002]

2. Description of the Related Art As high-density display is required in a fluorescent display tube, wiring for supplying electricity to the fluorescent display tube is simplified as much as possible, and the outer periphery of the fluorescent display tube is simplified in order to facilitate wiring. A chip-on-glass (CIP) fluorescent display tube (hereinafter abbreviated as a COG fluorescent display tube) in which a driving semiconductor element is mounted on a substrate constituting a part of the device outside the envelope and connected by wiring. What is known is known.

In this type of COG fluorescent display tube, a semiconductor element composed of an IC chip containing a driving circuit is positioned and arranged on a substrate, and a terminal portion (metal bump) of the semiconductor element is provided.
As a method of connecting between the wiring extending from the inside of the envelope to the outside and formed on the substrate, a face-down method of mounting the semiconductor device with the terminal portion of the semiconductor element facing the substrate is adopted. I have.

As the face-down method, there are a method using a conductive adhesive, a method using an anisotropic conductive material, and a method using Au.
Although a direct connection using a bump or the like is known, a face-down method using an anisotropic conductive material directly related to the present invention will be described here.

FIG. 4 is a side sectional view showing an example of a conventional COG fluorescent display tube in which the wiring of the substrate and the terminal of the semiconductor element are connected by using an anisotropic conductive material, and FIG. FIG. 3 is an enlarged view of a connection portion between a wiring and a terminal portion of a semiconductor element.

The COG fluorescent display tube shown in FIG. 4 is based on an insulating and translucent substrate 1 made of glass or the like.
An anode conductor 2 having a predetermined pattern is formed on the inner surface of the substrate 1, and a phosphor layer 3 is formed on the anode conductor 2 in a desired pattern. As shown in FIG. 5, a wiring conductor 4 for supplying electricity to the anode conductor 2 and other electrodes is formed on the inner surface of the substrate 1, and an insulating layer 5 is formed so as to cover the wiring conductor 4. .

[0007] As shown in FIG. 4, a filament-shaped cathode 6 serving as an electron source is stretched over the substrate 1. A control electrode 7 is provided between the cathode 6 and the phosphor layer 3 for controlling acceleration of electrons emitted from the cathode 6 toward the phosphor layer 3.
Is provided. Then, the substrate 1, the frame-shaped side plate 8 and the flat cover plate 9 are integrated via a sealing material 10 such as low-melting frit glass, and a fluorescent light display tube portion having an airtight envelope 11 is formed. Be composed.

As shown in FIG. 4, a part of the substrate 1 is protruded separately from the fluorescent display tube portion and extends outside the hermetic envelope 11, and the substrate 1 on which the semiconductor element 12 is mounted is mounted. The portion 1a is formed. The wiring conductor 4 extends from the inside of the hermetic envelope 11 on the mounting portion 1a.

Usually, many wiring conductors 4 are arranged on the substrate 1 at a fine pitch in many cases, and the width thereof is often small and shows a high resistance value. For this reason, ITO (Ind
It is difficult to form the wiring conductor 4 using a high-resistance conductive material such as iumTin Oxide).
The wiring conductor 4 is formed by the film.

As shown in FIG. 4 and FIG.
2 has a metal bump 12a made of Au, Ag, Ni, Cu, solder or the like. A plurality of metal bumps 12a are arranged on both sides of the bottom surface of the semiconductor element 12 having a rectangular shape at predetermined intervals to face each other. Each metal bump 12a
It is electrically connected to the wiring conductor 4 via the anisotropic conductive material 13.

The anisotropic conductive material 13 is a sheet-like film in which conductive particles (for example, Au balls having a particle size of about 5 μm) 13b are uniformly dispersed in a thermosetting adhesive 13a such as an epoxy resin. In the case where the wiring conductor 4 of the substrate 1 is electrically connected to the metal bump 12a of the semiconductor element 12, a sheet-shaped anisotropic conductive material 13 is placed on the wiring conductor 4 of the substrate 1, and Then, the semiconductor element 12 is positioned and arranged, and thermocompression bonding is performed from above the semiconductor element 12.

As a result, the anisotropic conductive material 13 is heated and pressed to melt the adhesive 13a, and the conductive particles 13b uniformly dispersed in the adhesive 13a face the wiring conductor 4 facing the conductive material 13b.
By being trapped between the metal bumps 12a, high conductivity is obtained in the thickness direction. Also, regarding the surface direction,
Since the conductive particles 13b are uniformly dispersed to the extent that they do not contact each other and the adhesive 13a is made of a non-conductive material, high insulation properties can be obtained. As a result, the semiconductor device 12
Each metal bump 12a is electrically connected only to the corresponding wiring conductor 4 on the substrate 1 while being mechanically fixed.

As described above, when the anisotropic conductive material 13 is used to connect the wiring conductors (terminals 4a of the wiring) 4 of the substrate 1 and the metal bumps (terminals) 12a of the semiconductor element 12, as shown in FIG. Conductive particles (Au ball) 1 in adhesive 13a
The conduction state is confirmed by observing the degree of collapse of 3b with an optical microscope. The degree of collapse of the conductive particles 13b is an important factor in confirming the conduction state. That is, when the conductive particles 13a in the adhesive 13a are not crushed at all, conduction between the metal bumps 12a of the semiconductor element 12 and the wiring conductors 4 on the substrate 1 becomes incomplete, which may lead to poor conduction. . Further, even when the conductive particles 13b are excessively crushed, when the temperature changes, the conductive particles 13b
b does not return, and the metal bump 12
a and the wiring conductor 4 on the substrate 1 may cause poor conduction. For this reason, the metal bump 12 of the semiconductor element 12
It is preferable that several crushed conductive particles 13b are present between a and the wiring conductor 4 on the substrate 1.

[0014]

However, in the above-mentioned conventional COG fluorescent display tube, when there are many wirings in a compact configuration, a transparent conductive film having a high specific resistance such as ITO is not used, and a low-resistance Al film is used. The wiring conductor 4 is
Formed on top. Then, the wiring conductor 4 is formed of an Al film, and the wiring conductor 4 and the metal bump 12 of the semiconductor element 12 are formed.
Since the anisotropic conductive material 13 is used for the connection between the conductive particles 13a and the conductive particles (Au balls) 13b of the anisotropic conductive material 13 from outside the substrate 1, The degree of collapse could not be observed.

Therefore, in order to check the continuity connection between the wiring conductor 4 on the substrate 1 and each metal bump 12a of the semiconductor element 12, the connection between the wiring conductor 4 and each metal bump 12a of the semiconductor element 12 must be determined. A tedious operation such as conducting a continuity test of the device was indispensable.

Therefore, the present invention has been made in view of the above problems, and a connection state between a terminal portion of a driving semiconductor element and a wiring on a substrate can be observed from outside the substrate. It is another object of the present invention to provide a COG fluorescent display tube in which alignment can be easily confirmed after connection and process management is easy.

[0017]

In order to achieve the above object, the invention according to claim 1 is to extend from inside of the hermetic envelope to outside on a light-transmitting substrate forming a part of the hermetic envelope. The space between the wiring conductor that has been output and wired and the driving semiconductor element having a metal bump on the bottom surface is formed outside the hermetic envelope by an anisotropic conductive material in which conductive particles are uniformly dispersed in an adhesive. In the chip-on-glass fluorescent display tube conductively connected with the above, a dummy bump made of a metal material that does not contribute to driving of the semiconductor element is formed on the semiconductor element, and a metal bump is formed on the substrate facing the dummy bump. A frame-shaped window cutout pattern is formed, and the degree of collapse of the conductive particles of the anisotropic conductive material can be observed from outside the substrate through a window cutout portion of the window cutout pattern. .

According to a second aspect of the present invention, in the COG fluorescent display tube according to the first aspect, the dummy bumps are formed at four corners of a bottom portion of the semiconductor element, and the window-opening patterns face each of the dummy bumps. It is characterized by being formed on the glass substrate.

The third aspect of the present invention is the first aspect of the present invention,
In the G fluorescent display tube, the dummy bumps are formed to have substantially the same shape as the outer shape of the metal bumps, and the window cutout portion of the window cutout pattern is formed to have the same shape as the outer shape of the dummy bumps.

[0020]

FIG. 1 is a side sectional view showing an embodiment of a COG fluorescent display tube according to the present invention, and FIG. 2 is a partially enlarged plan view of a wiring conductor and a windowed pattern in the configuration of FIG.

The COG fluorescent display tube of this embodiment has the same configuration as the COG fluorescent display tube shown in FIGS. 4 and 5 except for the configuration described below, and a description thereof will be omitted.

In the COG fluorescent display tube of the present embodiment, as shown in FIG. 1, a dummy bump 12b which does not contribute to driving of the semiconductor element 12 is provided on the bottom of the semiconductor element 12, as shown in FIG. . Dummy bump 12
b indicates that the metal bump 12
It is provided outside the metal bumps 12a in parallel with the arrangement of "a". The dummy bump 12b has substantially the same shape as the outer shape of the metal bump 12a (for example, 50 × 80 μm, 100 × 100 μm).
m). The dummy bumps 12b are formed on at least one of the bottom surfaces of the semiconductor element 12.
Provided at the location. However, in order to more reliably monitor the conductive connection state between the wiring conductor 4 of the substrate 1 and each of the metal bumps 12a of the semiconductor element 12, four corners of the bottom surface of the semiconductor element 12, preferably at both sides, at a predetermined pitch. The semiconductor element 12 is arranged in parallel with the arrangement of the plurality of metal bumps 12a to be arranged.
The dummy bumps 12b are provided at the four corners of the bottom surface of the dummy bump 12b.

On the substrate 1, a frame-shaped window opening pattern 15 made of a metal material is formed so as to face the dummy bump 12b. Note that the dummy bumps 12b are
In the case of being provided at the four corners of the bottom surface of the above, a window opening pattern 15 is formed on the substrate 1 so as to face each dummy bump 12b. The window opening portion of the window opening pattern 15 corresponds to the outer shape of the surface of the dummy bump 12b (the semiconductor element 12 corresponding to the terminal portion).
Of the metal bump 12a). Further, it is preferable that the window opening pattern 15 is formed in the same step with the same metal material as the wiring conductor 4 on the substrate 1. For example, the window opening pattern 15 can be formed simultaneously with the wiring conductor 4 in a frame shape with an Al thin film having a thickness of about 1.0 μm.

When the COG fluorescent display tube having the above structure is completed, each metal bump 12a of the semiconductor element 12 is formed.
And the wiring conductor 4 of the substrate 1 corresponding to each metal bump 12a
Is observed. This conductive state is observed by observing conductive particles (Au balls) 13b dispersed in the adhesive 13a of the anisotropic conductive material 13 which can be seen in the window opening pattern 15 from the outside of the substrate 1 having translucency. Particle 13b
Is determined based on the degree of collapse.

As described above, according to the COG fluorescent display tube of this embodiment, the dummy bumps 12b which do not contribute to the driving of the semiconductor element 12 are provided on the bottom surface of the semiconductor element 12, and have a light-transmitting property facing the dummy bumps 12b. Since the window opening pattern 15 is formed on the substrate 1, the window opening portion of the window opening pattern 15 can be uniformly dispersed in the adhesive 13 a of the anisotropic conductive material 13 by looking through the window opening portion of the window opening pattern 15 from outside the substrate 1 with an optical microscope. The degree of crushing of the conductive particles (Au ball) 13b to be performed can be observed.

When the dummy bumps 12b and the metal bumps 12a have substantially the same shape as the outer shapes of the dummy bumps 12b and the window bumps 15b, the outer shape of the dummy bumps 12b is substantially the same as the outer shape of the dummy bumps 12b. Since the pressure is applied by the anisotropic conductive material under substantially the same conditions as between the metal bumps 12a and the wiring conductors 4, the conductive particles 13b of the anisotropic conductive material 13 visible in the window opening portion of the window opening pattern 15 are crushed. By conducting the representative observation, it is possible to confirm the conductive connection state between each metal bump 12a of the semiconductor element 12 and the wiring conductor 4 of the substrate 1.

Further, in addition to the above configuration, the semiconductor device 12
Dummy bumps 12b are provided at the four corners of the bottom surface of the semiconductor element 12 so as to surround the metal bumps 12a, and a window pattern 15 is formed on the substrate 1 so as to face the dummy bumps 12b. Even when the semiconductor element 12 is mounted obliquely, the conductive connection state of all the metal bumps 12a of the semiconductor element 12 to the wiring conductor 4 is changed from the windowed portions of the four windowed patterns 15 to the conductive particles of the anisotropic conductive material 13. It can be confirmed by observing the degree of collapse of 13b. Moreover, since the dummy bumps 12b and the window-forming patterns 15 have substantially the same shape as the outer shape of the metal bumps 12a, the semiconductor element 12 is mounted on the substrate 1 so that the outer shape of each dummy bump 12b matches the outer shape of each of the window-opening patterns 15.
The semiconductor element 12 is positioned above the substrate 1.
It can be aligned to the exact position above. After the connection using the anisotropic conductive material 13, the wiring conductor 4
It can be confirmed whether or not the connection between the semiconductor device 12 and each metal bump 12a is made at a correct position. Then, as described above, the conductive particles 13 of the anisotropic conductive material 13
Since the degree of collapse of b can be monitored from the outside of the substrate 1 through the window opening portion of the window opening pattern 15, there is also an advantage that process control is easy.

By the way, the COG constructed as described above
In the fluorescent display tube, a continuity test of each wiring conductor 4 formed on the substrate 1 is performed before the semiconductor element 12 is mounted. This continuity test is performed by applying a test pin to the terminal portion 4a of the wiring conductor 4 immediately below the metal bump 12a, so that the terminal portion 4a of the wiring conductor 4 conductively connected to the metal bump 12a of the semiconductor element 12 is connected to the test pin. Being hurt by
There is a possibility that a connection failure may occur due to chipping.

Therefore, in the COG fluorescent display tube of the present embodiment, the inspection terminal portion 4b is integrally formed for each wiring conductor 4. Specifically, as shown in FIG.
Are extended inwardly of the semiconductor element 12 from the front ends of the terminal portions 4a of the wiring conductors 4 facing the metal bumps 12a of the semiconductor element 12, and are integrally formed. Note that the inspection terminal portion 4b only needs to have an area large enough to allow inspection by contact with the inspection pin, and its shape is not limited.

When the inspection of each wiring conductor 4 is performed in the inspection step before the mounting of the semiconductor element 12, each wiring conductor 4
The inspection is performed by applying an inspection pin to the inspection terminal portion 4b. Thus, the surface of the terminal portion 4a of each wiring conductor 4 electrically connected to the metal bump 12a of the semiconductor element 12 via the anisotropic conductive material 13 is not damaged by the inspection pin, and the terminal portion 4a of the wiring conductor 4 is not damaged. Can be kept smooth, and connection failure of each wiring conductor 4 can be eliminated.

[0031]

As is apparent from the above description, in the COG fluorescent display tube of the present invention, a dummy bump is provided on the bottom of a semiconductor element, and a window opening pattern is formed on a light-transmitting substrate facing the dummy bump. Because of the configuration, the semiconductor device is observed from the outside of the substrate by observing the window opening portion of the window opening pattern with an optical microscope and observing the degree of collapse of the conductive particles uniformly dispersed in the adhesive of the anisotropic conductive material. The conductive connection state between each metal bump of the element and the wiring conductor of the substrate can be confirmed.

If the dummy bumps and the metal bumps have substantially the same outer shape and the window cutout pattern is formed to have substantially the same shape as the outer shape of the surface of the dummy bumps, the space between the dummy bump and the window cutout is the same as that between the metal bump and the wiring conductor. Since it is compressed by the anisotropic conductive material under substantially the same conditions, by observing the degree of crushing of the conductive particles of the anisotropic conductive material which can be seen in the window opening portion of the window opening pattern, each metal of the semiconductor element can be observed. The conductive connection state between the bump and the wiring conductor of the substrate can be confirmed.

In addition to the above structure, if dummy bumps are provided at four corners of the bottom surface of the semiconductor element so as to surround the metal bumps of the semiconductor element, and a window pattern is formed on the substrate so as to face these dummy bumps, The conductive connection state of all the metal bumps of the element to the wiring conductor can be confirmed by observing the degree of collapse of the conductive particles of the anisotropic conductive material from the windowed portions of the four windowed patterns. In addition, since the dummy bumps and the window-opening pattern have substantially the same shape as the outer shape of the metal bumps, the semiconductor elements are arranged on the substrate such that the outer shape of each dummy bump matches the outer shape of each window-out pattern. Can be aligned to the exact position of Further, after the connection using the anisotropic conductive material, it is possible to confirm whether or not the connection between the wiring conductor of the substrate and each metal bump of the semiconductor element is made at a correct position. Further, as described above, the degree of crushing of the conductive particles of the anisotropic conductive material can be monitored from the outside of the substrate through the window opening pattern.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a COG fluorescent display tube according to the present invention.

FIG. 2 is a partially enlarged plan view of a wiring conductor and a windowless pattern in the configuration of FIG. 1;

FIG. 3 is a side sectional view showing another embodiment of the COG fluorescent display tube according to the present invention.

FIG. 4 is a side sectional view showing an example of a conventional COG fluorescent display tube in which wiring of a substrate and terminal portions of a semiconductor element are connected using an anisotropic conductive material.

5 is an enlarged view of a connection portion between a wiring on a substrate and a terminal portion of a semiconductor element in the configuration of FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 4 ... Wiring conductor, 4a ... Terminal part, 4b ... Inspection terminal part, 11 ... Hermetic enclosure, 12 ... Semiconductor element, 12a
... metal bumps (terminals), 12b ... dummy bumps, 13
... anisotropic conductive material, 13a ... adhesive, 13b ... conductive particles,
15 ... Pattern without window.

Claims (3)

[Claims] 1. A driving device having a wiring conductor extending from the inside of the hermetic envelope to the outside and wired on a light-transmitting substrate forming a part of the hermetic envelope, and a metal bump on a bottom surface portion. A chip-on-glass fluorescent display tube electrically connected between the semiconductor element and the outside of the hermetic envelope by an anisotropic conductive material in which conductive particles are uniformly dispersed in an adhesive material; A dummy bump made of a metal material that does not contribute to driving of the semiconductor element is formed, and a frame-shaped window-opening pattern made of a metal material is formed on the substrate facing the dummy bump. A chip-on-glass fluorescent display tube, wherein the degree of crushing of the conductive particles of the anisotropic conductive material can be observed through a window portion of the window pattern. 2. The semiconductor device according to claim 1, wherein the dummy bumps are formed at four corners of a bottom surface of the semiconductor element, and the window-opening pattern is formed on the glass substrate so as to face each of the dummy bumps. Item 7. A chip-on-glass fluorescent display tube according to item 1. 3. The dummy bump is formed to have substantially the same shape as the outer shape of the metal bump, and the window cutout portion of the window cutout pattern is formed to have substantially the same shape as the outer shape of the dummy bump. 3. The chip-on-glass fluorescent display tube according to 1 or 2.